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Red Hat Developer Toolset 2.x User Guide

1. 4 Some newer library features are statically linked into applications built with Red Hat Developer Toolset to support execution on multiple versions of Red Hat Enterprise Linux This adds a small additional security risk as normal Red Hat Enterprise Linux errata would not change this code If the need for developers to rebuild their applications due to such an issue arises Red Hat will signal this via a security erratum Developers are strongly advised not to statically link their entire application for the same reasons gfortran v Example 3 5 Compiling a Fortran Program on the Command Line Consider a source file named hello f with the following contents fa To compile this source code on the command line by using the gfortran compiler from Red Hat Developer Toolset type program hello prine seio Would end program hello Y SS scl enable devtoolset 2 gfortran o hello hello f lt This creates a new binary file called hello in the current working directory 3 3 3 Running a Fortran Program When gfortran compiles a program it creates an executable binary file To run this program on the command line change to the directory with the executable file and type A gt Z file name M Red Hat Developer Toolset 2 x User Guide Example 3 6 Running a Fortran Program on the Command Line hello Hello World 3 4 Additional
2. scl enable devtoolset 2 strace program argument Replace program with the name of the program you want to analyze and argument with any command line options and arguments you want to supply to this program Alternatively you can run the utility on an already running process by using the p command line option followed by the process ID scl enable devtoolset 2 strace p process id Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset strace as default scl enable devtoolset 2 bash rraumm To verify the version of strace you are using at any point type the following at a shell prompt which strace Red Hat Developer Toolset s strace executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset strace strace V 8 2 1 Redirecting Output to a File By default strace prints the name of each system call its arguments and the return value to standard error output To redirect this output to a file use the o command line option followed by the file name 56 Chapter 8 strace scl enable devtoolset 2 strace o file_name program argument Replace file_name with the name of the file Exampl
3. stapsh Serves as a remote shell for SystemT ap stap prep Determines and if possible downloads the kernel information packages that are required to run SystemT ap stap merge Merges per CPU files This script is automatically executed when the stap utility is executed with the b command line option stap report Gathers important information about the system for the purpose of reporting a bug in SystemT ap 10 1 Installing SystemTap In Red Hat Developer Toolset SystemTap is provided by the devtoolset 2 systemtap package and is In order to place instrumentation into the Linux kernel SystemT ap may also require installation of additional packages with debugging information To determine which packages to install run the stap prep utility as follows scl enable devtoolset 2 stap prep Note that if you execute this command as the root user the utility automatically offers the packages for installation For more information on how to install these packages on your system see the Red Hat Enterprise Linux SystemTap Beginners Guide 10 2 Using SystemTap To execute any of the tools that are part of SystemT ap type the following at a shell prompt scl enable devtoolset 2 tool option N o Red Hat Developer Toolset 2 x User Guide are distributed with SystemT ap For example to run the stap tool to build an instrumentation module type scl enable devtoolset 2 stap option argument Note that you can
4. 6 Red Hat Developer Toolset 2 x User Guide A 3 3 2 Compatibility Changes Changes Since Red Hat Enterprise Linux 5 9 A 4 Changes in elfutils A 4 1 Changes Since Red Hat Developer Toolset 1 1 A 4 2 Changes Since Red Hat Enterprise Linux 6 4 A 4 3 Changes Since Red Hat Enterprise Linux 5 9 A 5 Changes in dwz A 5 1 Changes Since Red Hat Developer Toolset 1 1 A 6 Changes in GDB A 6 1 Changes Since Red Hat Developer Toolset 1 1 A 6 2 Changes Since Red Hat Enterprise Linux 6 4 New Features Compatibility Changes A 6 3 Changes Since Red Hat Enterprise Linux 5 9 New Features A 7 Changes in strace A 7 1 Changes Since Red Hat Enterprise Linux 6 4 and 5 9 A 8 Changes in SystemT ap A 8 1 Changes Since Red Hat Developer Toolset 1 1 A 9 Changes in OProfile A 9 1 Changes Since Red Hat Developer Toolset 1 1 A 9 2 Changes Since Red Hat Enterprise Linux 5 9 A 10 Changes in Valgrind A 10 1 Changes Since Red Hat Developer Toolset 1 1 A 10 2 Changes Since Red Hat Enterprise Linux 5 9 lt NWDWOZZO TOATTAMVADWDSY 120 120 120 120 121 121 122 122 122 122 125 125 129 130 130 133 133 133 133 134 134 134 135 135 135 Table of Contents Red Hat Developer Toolset 2 x User Guide Preface 1 Document Conventions This manual uses several conventions to highlight certain words and phrases and draw attention to specific pieces of information Liberation Fonts set is also used in HTML editions if the set is install
5. After purchasing a Red Hat subscription this is where you go to activate it Note that the Activate a New Subscription section requires you to enter your Red Hat login and password Support Essentials Here you can find a list of articles and group discussions viewable by new posts most popular and recent comments as well as the most recent Red Hat errata Security Red Hat releases errata to address bugs provide enhancements or to fix security vulnerabilities With each erratum an advisory is supplied to give the details of the issues being fixed as well as how to obtain and install the required software packages This section has information about the errata including Checking the security update policy and lifetime for all Red Hat products Getting the latest security updates for Red Hat products Getting notified of new security updates 86 Chapter 15 Accessing the Customer Portal Finding out if a specific CVE affects a Red Hat product Reporting a security vulnerability How we measure security vulnerabilities Security Response Team mission and standards of service Support This is where all the information regarding Red Hat support can be found including links for Support Cases Support Programs Product Life Cycles Supported Environments Help amp Assistance Site Help 15 3 The Connect Menu Knowledgebase Groups PLAN CONNECT Videos Tech Briefs k Source Support Cases Figure
6. New catch load and catch unload commands have been added These commands allow you to stop execution of a debugged program when a shared library is loaded or unloaded A new command enable count has been added This command allows you to auto disable a breakpoint after several hits A new command info vtbl has been added This command allows you to show the virtual method tables for C and Java objects 127 Red Hat Developer Toolset 2 x User Guide Anew command explore has been added It supports two subcommands explore value and explore type and allows you to recursively explore values and types of expressions Note that this command is only available with Python enabled GDB Anew command dprintf location format args has been added This command allows you to create a dynamic printf type breakpoint which performs a printf like operation and then resumes program execution New set print symbol and show print symbol commands have been added These commands allow you to control whether GDB attempts to display the symbol if any that corresponds to addresses it prints This functionality is enabled by default but you can restore the previous behavior by running the set print symbol off command New set breakpoint condition evaluation and show breakpoint condition evaluation commands have been added These commands allow you to control whether breakpoint conditions are evaluated by GDB the host option or by gdbserver the target o
7. Reference Architectures contains a list of whitepapers that detail technical case studies of solutions that have been built tested and bench marked by senior Red Hat engineers They explain the capabilities and limitations of a given solution as well as detailed notes on how to implement the solution Evaluations amp Demos You can download free evaluations of various Red Hat products from here including Red Hat Enterprise Linux Red Hat Enterprise Virtualization Red Hat Storage Appliance and JBoss Enterprise Middleware evaluations 85 Red Hat Developer Toolset 2 x User Guide Certified Hardware This section has information on what systems components and peripherals Red Hat Enterprise Linux 6 5 and 4 support 15 2 The Deploy Menu E S gt Getting Started Downloads PLAN DEPLOY h Activate a New Subscription Support Essentials Security Support Figure 15 2 The Deploy Menu In the Deploy menu are resources needed to deploy a development project This includes Getting Started The Getting Started page has links to information to help get up and running with Red Hat subscriptions including product registration information accessing your resources and engaging in global support It also has links to a Red Hat Welcome Kit and a Quick Guide to Red Hat Support Downloads Here is where you can download all that Red Hat offers with descriptions of what each entails Activate a New Subscription
8. For example to display a list of optimizations that were enabled by the 02 option but had no effect when compiling a file named foo c type gcc 02 fopt info missed foo c New floop nest optimize Option A new command line option f loop nest optimize has been added This option enables an experimental ISL based loop nest optimizer a generic loop nest optimizer that is based on the Pluto optimization algorithms and that calculates a loop structure optimized for data locality and paralelism Hot and Cold Attributes on Labels The hot and cold function attributes can now also be applied to labels Hot labels tell the compiler that the execution path following the label is more likely than any other execution path and cold labels convey the opposite meaning These attributes can be used in cases where builtin expect cannot be used for instance with a computed goto or asm goto A 2 1 3 Debugging Enhancements DWARFA DWARF4 is now used as the default debugging data format when generating debugging information T o get the maximum benefit from this new debugging representation use the latest version of Valgrind elfutils and GDB included in this release New gsplit dwarf Option A new command line option gsplit dwarf has been added This option tells the compiler driver to separate as much DWARF debugging information as possible into a separate output file with the dwo file extension and allows the build system to avoid linking
9. Source section requires you to enter your Red Hat login and password Support Cases This is where users can view all their support cases make changes or view any updates Note that the Support Cases section requires you to enter your Red Hat login and password Chapter 16 Contacting Global Support Services Chapter 16 Contacting Global Support Services Unless you have a Self Support subscription when both the Red Hat Documentation website and Customer Portal fail to provide the answers to your questions you can contact Global Support Services GSS 16 1 Gathering Required Information Several items of information should be gathered before contacting GSS Background Information Ensure you have the following background information at hand before calling GSS Hardware type make and model on which the product runs Software version Latest upgrades Any recent changes to the system An explanation of the problem and the symptoms Any messages or significant information about the issue raummmm If you ever forget your Red Hat login information it can be recovered at Diagnostics The diagnostics report for Red Hat Enterprise Linux is required as well This report is also known as a sosreport and the program to create the report is provided by the sos package To install the sos package and all its dependencies on your system type the following at a shell prompt as root yum install so
10. kill or k for short command line option scl enable devtoolset 2 memstomp kill program argument The use of the kill option is especially recommended if you are analyzing a multi threaded program the internal implementation of backtraces is not thread safe and running the memstomp utility on a multi threaded program without this command line option can therefore produce unreliable results Additionally if you have compiled the analyzed program with the debugging information or this debugging information is available to you you can use the debug info or d command line option to produce a more detailed backtrace scl enable devtoolset 2 memstomp debug info program argument For detailed instructions on how to compile your program with the debugging information built in the Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset memstomp as default scl enable devtoolset 2 bash 63 Red Hat Developer Toolset 2 x User Guide Example 9 1 Using memstomp In the current working directory create a source file named employee c with the following contents include lt stdio h gt include lt string h gt define BUFSIZE 80 int main int argc char argv char employee BUFSIZE John Doe
11. opcontrol 1 opgprof 1 ophelp 1 opimport 1 opreport 1 Manual pages for various tools distributed with OProfile provide more information on their respective usage To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 2 man tool Online Documentation Linux 5 describes in detail how to install configure and start using OProfile on this system 74 Chapter 12 OProfile See Also the Red Hat Enterprise Linux system version of OProfile and the version distributed in the previous release of Red Hat Developer Toolset and memory management problems such as the use of uninitialized memory improper allocation and freeing of memory and the use of improper arguments in system calls executable 75 Red Hat Developer Toolset 2 x User Guide Chapter 13 Dyninst The Dyninst library provides an application programming interface API for instrumenting and working with user space executables during their execution It can be used to insert code into a running program change certain subroutine calls or even remove them from the program and serves as a valuable debugging and performance monitoring tool The Dyninst API is also commonly used along with SystemT ap to allow non root users to instrument user space executables Red Hat Developer Toolset is distributed with Dyninst 8 0 13 1 Installing Dyninst In Red Hat Developer Toolset the Dyninst library is provide
12. yt This happens atomically even in a multi threaded execution of the program In particular even though the transaction can load x and y and store to y all these memory accesses are virtually executed as one indivisible step Note that in line with the C 11 memory model programs that use transactions must be free of data races Transactions are guaranteed to be virtually executed serially in a global total order that is determined by the transactional memory implementation and that is consistent with and contributes to the happens before order enforced by the rest of the program that is transaction semantics are specified based on the C 11 memory model see the draft specification linked above Nonetheless if a program is not data race free then it has undefined behavior For example a thread can first initialize some data and then make it publicly accessible by code like this init data transaction atomic data public true data public is initially false Another thread can then safely use the data for instance transaction atomic if data public use data However the following code has a data race and thus results in undefined behavior transaction atomic temp copy data if data public use temp Here copy data races with init data in the initializing thread because this can be executed even if data public is not true Another example for data races is one thread accessing a variable x transac
13. ANH have been added for real and complex arguments and AT AN Y X now serves as an alias for AT AN2 Y X The BLOCK construct has been implemented A 2 2 2 4 6 Fortran 2008 Compatibility The implementation of the ASYNCHRONOUS attribute in GCC is now compatible with the candidate draft of TS 29113 Technical Specification on Further Interoperability with C A 2 2 2 4 7 Fortran 77 Compatibility When the GNU Fortran compiler is issued with the fno sign zero option the SIGN intrinsic now behaves as if zero were always positive A 2 2 3 ABI Compatibility This section describes compatibility between the Red Hat Developer Toolset compilers and the system compilers at the application binary interface ABI level A 2 2 3 1 C ABI Because the upstream GCC community development does not guarantee C 11 ABI compatibility across major versions of GCC the same applies to use of C 11 with Red Hat Developer Toolset Consequently using the std c 11 option is supported in Red Hat Developer Toolset 2 0 only when all C objects compiled with that flag have been built using the same major version of Red Hat Developer Toolset The mixing of objects binaries and libraries built by the Red Hat Enterprise Linux 5 or 6 system toolchain GCC using the std c 0x or std gnu 0x flags with those built with the std c 11 or std gnu 11 flags using the GCC in Red Hat Developer Toolset is explicitly not supported As later major versions of
14. Resources A detailed description of the GNU Compiler Collections and its features is beyond the scope of this book For more information see the resources listed below Installed Documentation gcc 1 The manual page for the gcc compiler provides detailed information on its usage with few exceptions g accepts the same command line options as gcc To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 2 man gcc gfortran 1 The manual page for the gfortran compiler provides detailed information on its usage To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 2 man gfortran C Standard Library Documentation Documentation on the C standard library can be optionally installed by typing the following at a shell prompt as root yum install devtoolset 2 libstdc docs Once installed HT ML documentation is available at opt rh devtoolset 2 root usr share doc devtoolset 2 libstdc docs 4 8 1 html index html Online Documentation information on gfortran s usage See Also Red Hat Enterprise Linux system version of the GNU Compiler Collection and the version distributed 36 Chapter 3 GNU Compiler Collection GCC in the previous release of Red Hat Developer Toolset as well as information about the language ABI and debugging compatibility and Fortran 37 Red Hat Developer Toolset 2 x
15. amp redhat Red Hat Developer Toolset 2 x User Guide Installing and Using Red Hat Developer Toolset Edition 1 Jaromir Hradilek Jaromir Hradilek Jacquelynn East Matt Newsome Red Hat Developer Toolset 2 x User Guide Installing and Using Red Hat Developer Toolset Edition Jarom r Hrad lek Red Hat Engineering Content Services jhradilek redhat com Jacquelynn East Red Hat Engineering Content Services jeast redhat com Matt Newsome Red Hat Software Engineering mnewsome redhat com Legal Notice Copyright 2013 Red Hat Inc This document is licensed by Red Hat under the Creative Commons Attribution ShareAlike 3 0 Unported License If you distribute this document or a modified version of it you must provide attribution to Red Hat Inc and provide a link to the original If the document is modified all Red Hat trademarks must be removed Red Hat as the licensor of this document waives the right to enforce and agrees not to assert Section 4d of CC BY SA to the fullest extent permitted by applicable law Red Hat Red Hat Enterprise Linux the Shadowman logo JBoss MetaMatrix Fedora the Infinity Logo and RHCE are trademarks of Red Hat Inc registered in the United States and other countries Linux is the registered trademark of Linus Torvalds in the United States and other countries Java is a registered trademark of Oracle and or its affiliates XFS is a trademark of Silicon Graphics International Corp or its subsidiar
16. distributed with GCC 4 8 which provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version and the version included in Red Hat Developer Toolset 1 1 Below is a comprehensive list of new features and compatibility changes in this release A 2 1 Changes Since Red Hat Developer Toolset 1 1 The following features have been added since the release of GCC included in Red Hat Developer Toolset 1 1 A 2 1 1 Caveats Aggressive Loop Optimizations The loop optimizer of GCC has been improved to use language constraints in order to derive bounds for the number of iterations of a loop The bounds are then used as a guide to loop unrolling peeling and loop exit test optimizations The optimizations assume that the loop code does not invoke undefined behavior by for example causing signed integer overflows or making out of bound array accesses For example consider the following code fragment unsigned int foo unsigned int data data 128 for int fd 0 fd lt 128 fd data data fd fd 0x02000001 error return data data 0 j 93 Red Hat Developer Toolset 2 x User Guide When the value of the fd variable is 64 or above the fd 0x02000001 operation overflows which is invalid in both C and C for signed integers In the example above GCC may generate incorrect code or enter an infinite loop To fix this error use the appropriate casts when converting between signed and
17. errors The error pass2 7stap manual page documents pass 2 elaboration errors The error pass3 7stap manual page documents pass 3 translation errors The error pass4 stap manual page documents pass 4 compilation errors The error pass5 7stap manual page documents pass 5 execution errors The error process tracking 7stap manual page documents user space process tracking errors The error reporting 7stap manual page documents how to report SystemT ap bugs The scripting language used by SystemT ap now supports the operator Users can use this operator to match regular expressions The preprocessor used by the stap utility now supports an experimental macro facility Users can use the following construct to define new macros Qdefine name parameter body Refer to the PREPROCESSOR MACROS section of the stap 1 manual page for more information on how to use this feature The backtrace related tapset functions have been improved and standardized A 9 Changes in OProfile Red Hat Developer Toolset 2 0 is distributed with OProfile 0 9 8 which provides a number of a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version and the version included in Red Hat Developer Toolset 1 1 Below is a comprehensive list of new features in this release A 9 1 Changes Since Red Hat Developer Toolset 1 1 The following features have been added since the release of OProfile include
18. files with debugging information In order to be useful this option requires a debugger capable of reading dwo files such as the version of GDB included in Red Hat Developer Toolset 2 0 95 Red Hat Developer Toolset 2 x User Guide rraumm elfutils SystemTap and Valgrind do not support the dwo files A 2 1 4 C Changes Experimental C Features from an Upcoming Standard g now supports a new command line option std c 1y This option can be used for experimentation with features proposed for the next revision of the standard that is expected around 2014 Currently the only difference from std c 11 is support for return type deduction in normal New thread_local Keyword g now implements the C 11 thread local keyword In comparison with the GNU _ thread keyword thread local allows dynamic initialization and destruction semantics See the next item for dynamic initialization issues Dynamic Initialization of Thread local Variables The C 11 and OpenMP standards allow thread local and thread private variables to have dynamic that is runtime initialization To support this any use of such a variable goes through a wrapper function that performs necessary initialization When the use and definition of the variable are in the same translation unit this overhead can be optimized away but when the use is in a different translation unit there is significant overhead even if the variable does not act
19. foo return 0 attribute target sse4 2 int foo return 1 attribute target arch atom int foo return 2 When the function foo is executed the result returned depends upon the architecture where the 98 Changes in Version 2 0 New RTM and HLE Intrinsics Support for the Intel RTM and HLE intrinsics built in functions and code generation has been added and can be enabled by using the mrtm and mhle command line options This is done via intrinsics for Restricted Transactional Memory RTM and extensions to the memory model for Hardware Lock Elision HLE For HLE two new flags can be used to mark a lock as using hardware elision ATOMIC HLE ACQUIRE Starts lock elision on a lock variable The memory model in use must be _ ATOMIC ACQUIRE or stronger _ ATOMIC HLE RELEASE Ends lock elision on a lock variable The memory model must be _ ATOMIC RELEASE or stronger For example consider the following code fragment while atomic exchange n amp lockvar 1 ATOMIC ACQUIRE ATOMIC HLE ACQUIRE mm pause work with the acquired lock atomic clear amp lockvar _ ATOMIC RELEASE ATOMIC HLE RELEASE The new intrinsics that support Restricted Transactional Memory are unsigned _xbegin void Attempts to start a transaction If it succeeds this function returns XBEGIN STARTED otherwise it returns a status value indicating why the transaction could not be st
20. has been added This function can be used to look up a global symbol GDB values in Python are now callable if the value represents a function A new module gdb types has been added A new module gdb printing has been added New commands info pretty printers enable pretty printer anddisable pretty printer have been added A new gdb parameter directories function call is now available A new function gdb newest frame has been added This function can be used to return the newest frame in the selected thread The gdb InferiorThread class now supports a new name attribute Support for inferior events has been added Python scripts can now add observers in order to be notified of events occurring in the process being debugged GDB commands implemented in Python can now be put in the gdb COMMAND_USER command class The maint set python print stack on off command has been removed and replaced by set python print stack A new class gdb printing FlagEnumerationPrinter has been added This class can be used to apply f lag enum style pretty printing to enums The gdb 1ookup symbol function now works correctly when there is no current frame The gdb Symbol object now has an additional attribute line This attribute holds the line number in the source at which the symbol was defined The gdb Symbol object now has an additional attribute needs frame and a new method value The needs frame attribute indicates whether the symbol requires a fram
21. is for SystemT ap probes the sys sdt h header file You can set a breakpoint by using the new probe pstap or probe stap options and inspect the probe arguments by using the new probe arg family of convenience variables The symbol reloading option has been deleted gdbserver now supports ST DIO connections for example Changes in Version 2 0 gdb target remote ssh myhost gdbserver hello GDB is now able to print flag enums In a flag enum all enumerator values have no bits in common when pairwise AND ed When GDB prints a value whose type is a flag enum GDB shows all the constants for example for enum E ONE 1 TWO 2 gdb print enum E 3 1 ONE TWO The file name part of a linespec now matches trailing components of a source file name For example break gcc expr c 1000 now sets a breakpoint in the build gcc expr c file but not in build libcpp expr c The info proc and generate core file commands now work on remote targets connected to gdbserver The command info catch has been removed The Ada specific catch exception and catch assert commands now accept conditions at the end of the command The info static tracepoint marker command now works on native targets with an in process agent GDB can now set breakpoints on inline functions The gdb index section has been updated to include symbols for inline functions By default GDB now ignores older gdb index sections until their gdb index sectio
22. its usage To display the manual page for the version included in Red Hat Developer Toolset type 44 Chapter 6 dwz scl enable devtoolset 2 man dwz See Also ELF files 45 46 Red Hat Developer Toolset 2 x User Guide Part IV Debugging Tools Chapter 7 GNU Debugger GDB Chapter 7 GNU Debugger GDB The GNU Debugger commonly abbreviated as GDB is a command line tool that can be used to debug programs written in various programming languages It allows you to inspect memory within the code being debugged control the execution state of the code detect the execution of particular sections of code and much more Red Hat Developer Toolset is distributed with GDB 7 6 This version is more recent than the version included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements including improved support for Python scripting ambiguous line specifications and tracepoints as well as improved inferior control commands and handling of C debugee executables For a detailed list of 7 1 Installing the GNU Debugger In Red Hat Developer Toolset the GNU Debugger is provided by the devtoolset 2 gdb package and is 7 2 Preparing a Program for Debugging Compiling Programs with Debugging Information To compile a C program with debugging information that can be read by the GNU Debugger make sure the gcc compiler is run with the g option To do so on the command line use a command in the following
23. john example com char name BUFSIZE 0 char surname BUFSIZE 0 char email size_t length Extract the information memccpy name employee BUFSIZE length strlen name memccpy surname employee length BUFSIZE length strlen surname email employee length Compose the new entry strcat employee surname strcpy employee name strcat employee email Print the result puts employee return 0 Compile this program into a binary file named employee by using the following command scl enable devtoolset 2 gcc rdynamic g o employee employee c To identify erroneous function calls with overlapping memory regions type 64 scl enable devtoolset 2 memstomp debug info employee memstomp 0 1 4 successfully initialized for process employee pid 14887 strcat dest 0x7fff13afc265 src 0x7fff13afc269 bytes 21 overlap for employee 14887 0 strcpy 0 strcpy 0 Exit 0 strcat employee c 26 main 0 libc start main 0 _start John john example comDoe Chapter 9 memstomp 9 3 Additional Resources A detailed description of memstomp and its features is beyond the scope of this book For more information see the resources listed below Installed Documentation memstomp 1 The manual page for the memstomp utility provides detailed information about its usage To display the manual page for the version
24. of task and application life cycle management plug ins has been updated from version 3 4 to 3 9 This update includes an enhanced task focused interface and task editing a new Jenkins Hudson connector enhanced Bugzilla and Trac connectors EPUB authoring tools A new EGit plug in has been added This plug in includes an Eclipse Team provider based on JGit a Git implementation written entirely in Java and adds support for the Git revision control system to the Eclipse user interface by introducing the History and Synchronize views Compare and Quick Diff menu items and various wizards to make it easier for developers to use this plug in New GCov integration has been added to allow the user to visualize GCov output in both summarized form and in file editors As well graphing capabilities for the data have been added New GProf integration has been added to allow the user to view profiling information such as execution time and call graphs As well graphing capabilities for the data have been added A new SystemTap integration plug in has been added This plug in includes an editor for the stp files with the autocomplete feature the Probe view with a list of probes that are available on the system the Function view with a list of functions that are available on the system and can be used in 92 Changes in Version 2 0 Stp scripts As well this plug in includes integration for running SystemT ap scripts and viewing the res
25. oprofiled 144 Revision History ranlib overview binutils readelf Red Hat Customer Portal see Customer Portal Red Hat Developer Toolset scl see Software Collections size overview binutils stap 145 Red Hat Developer Toolset 2 x User Guide stap merge staprun stapsh strace documentation Additional Resources installation Installing strace overview strace usage Using strace version About Red Hat Developer Toolset strace strings overview binutils usage Using Other Binary Tools strip overview binutils usage Using Other Binary Tools support Red Hat Developer Toolset About Red Hat Developer Toolset SystemTap documentation Additional Resources 146 Revision History Valgrind documentation Additional Resources version 147
26. option is now enabled by default When a fatal error occurs GNU Fortran now attempts to print a backtrace to standard error before aborting the execution of the program To disable this behavior use the fno backtrace option GNU Fortran no longer supports the use of the M command line option to generate Makefile dependencies for the module path To perform this operation use the J option instead To significantly reduce the number of warnings the Wconversion command line option now only 111 Red Hat Developer Toolset 2 x User Guide displays warnings when a conversion leads to information loss and a new command line option Wconversion extra has been added to display warnings about other conversions The Wconversion option is now enabled with Wall A new command line option Wunused dummy argument has been added This option can be used to display warnings about unused dummy arguments and is now enabled with Wall Note that the Wunused variable option previously also warned about unused dummy arguments The COMMON default padding has been changed Previously the padding was added before a variable Now it is added after a variable to increase the compatibility with other vendors as well as to help to obtain the correct output in some cases Note that this behavior is in contrast with the behavior of the falign commons option GNU Fortran no longer links against the 1ibgfortranbegin library The MAIN assembler symbol is the act
27. or archive files strings Displays printable character sequences in files strip Discards all symbols from object files 4 1 Installing binutils In Red Hat Developer Toolset binutils are provided by the devtoolset 2 binutils package and are 4 2 Using the GNU Assembler To produce an object file from an assembly language program run the as tool as follows Chapter 4 binutils scl enable devtoolset 2 as option o object file source file This creates an object file named object file in the current working directory Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset as as default scl enable devtoolset 2 bash rraauA To verify the version of as you are using at any point type the following at a shell prompt which as Red Hat Developer T oolset s as executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset as as v 4 3 Using the GNU Linker To create an executable binary file or a library from object files run the 1d tool as follows scl enable devtoolset 2 ld option o output file object file This creates a binary file named output file in the current working
28. time the breakpoint is reached To execute next three lines of code type gdb step 3 13 b sum This allows you to verify the current value of the sum variable before it is assigned to b gdb print sum 3 2 7 9 Additional Resources A detailed description of the GNU Debugger and all its features is beyond the scope of this book For more information see the resources listed below Online Documentation reference material See Also Red Hat Enterprise Linux system version of the GNU Debugger and the version distributed in the previous release of Red Hat Developer Toolset with overlapping memory regions that are not allowed by various standards 54 Chapter 7 GNU Debugger GDB 55 Red Hat Developer Toolset 2 x User Guide Chapter 8 strace strace is a diagnostic and debugging tool for the command line that can be used to trace system calls that are made and received by a running process It records the name of each system call its arguments and its return value as well as signals received by the process and other interactions with the kernel and prints this record to standard error output or a selected file Red Hat Developer Toolset is distributed with strace 4 7 8 1 Installing strace In Red Hat Enterprise Linux the strace utility is provided by the devtoolset 2 strace package and is 8 2 Using strace To run the strace utility on a program you want to analyze type the following at a shell prompt
29. to extend your runtime limits for stack memory Compile time has been significantly improved For example the improvement may be noticeable when 110 Changes in Version 2 0 working with programs that use large array constructors To improve code generation and diagnostics the fwhole file compile flag is now enabled by default and can be used with a newly supported fwhole program flag To disable it use the deprecated fno whole file flag A new command line option M is now supported Similarly to gcc this option allows you to generate Makefile dependencies Note that the cpp option may be required as well The finit real command line option now supports snan as a valid value This allows you to initialize REAL and COMPLEX variables with a signaling NaN not a number and requires you to enable trapping for example by using the f fpe trap command line option Note that compile time optimizations may turn a signaling NaN into a quiet NaN A new command line option fcheckz has been added This option accepts the following arguments The fcheck bounds option is equivalent to the fbounds check command line option The fcheck array temps option is equivalent to the fcheck array temporaries command line option The fcheck do option checks for invalid modification of loop iteration variables The fcheckzrecursive option checks for recursive calls to subroutines or functions that are not marked as recursive The fcheck pointer o
30. to those files A new command line option F has been added to the obj dump tool This option can be used to include file offsets in the disassembly A new command line option c has been added to the readelf tool This option can be used to allow string dumps of archive symbol index The i386 port now supports the SSE5 instruction set A new command line option p has been added to the readelf tool This option can be used to allow string dumps of sections A 3 3 2 Compatibility Changes Changes Since Red Hat Enterprise Linux 5 9 The following compatibility changes have been made since the release of binutils included in Red Hat Enterprise Linux 5 9 The as needed command line option has been adapted to link in a dynamic library in the following two cases 1 if the dynamic library satisfies undefined symbols in regular objects and 2 if the dynamic library satisfies undefined symbols in other dynamic libraries unless the library is already found in a DT NEEDED entry of one of the libraries that are already linked A 4 Changes in elfutils Red Hat Developer Toolset 2 0 is distributed with elfutils 0 155 which provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version and the version included in Red Hat Developer Toolset 1 1 Below is a comprehensive list of new features in this release A 4 1 Changes Since Red Hat Developer Toolset 1 1 The following features have been added s
31. transactions Furthermore relaxed transactions are likely to be executed with less performance but this depends on the implementation and available hardware GCC verifies these restrictions statically at compile time for example the requirements on code allowed to be called from within atomic transactions This has implications for when transactions call functions that are defined within other compilation unit source file or within libraries To enable such cross compilation unit calls for transactional code the respective functions must be marked to contain code that is safe to use from within atomic transactions Programmers can do so by adding the transaction_safe function attribute to the declarations of these functions and by including this declaration when defining the function In turn GCC then verifies that the code in these functions is safe for atomic transactions and generates code accordingly If the programmer does not follow these constraints and or steps compile time or link time errors occur Note that within a compilation unit GCC detects automatically whether a function is safe for use within transactions and the attributes therefore typically do not need to be added See the draft specification linked above for further details GCC s transactional memory support is designed in such a way that it does not decrease the performance of programs that do not use transactions nor the performance of nontransactional code except du
32. unsigned types to avoid overflows for instance data data fd uint32 t fd 0x02000001U ok If necessary this optimization can be turned off by using the new command line option fno aggressive loop optimizations A 2 1 2 General Improvements and Changes New Local Register Allocator GCC 4 8 features a new Local Register Allocator LRA which replaces the 26 year old reload pass and improves the quality of generated code The new local register allocator is meant to be simpler easier to debug and does a better job of register allocation AddressSanitizer A fast memory error detector called AddressSanitizer has been added and can be enabled by using the fsanitize address command line option It augments memory access instructions in order to detect use after free and out of bound accesses to objects on the heap ThreadSanitizer A fast data race detector called ThreadSanitizer has been added in GCC 4 8 The option to enable this feature is fsanitize thread Compiling Extremely Large Functions Many scalability bottlenecks have been removed from GCC optimization passes As a consequence it is now possible to compile extremely large functions with smaller memory consumption in less time New Og Optimization Level A new general optimization level Og has been introduced This optimization level addresses the need for fast compilation and a superior debugging experience while providing a reasonable level of runtim
33. utility now provides improved support for decoding of arguments for various system calls In addition a number of new system calls are supported A 8 Changes in SystemTap Red Hat Developer Toolset 2 0 is distributed with SystemTap 2 1 which provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version and the version included in Red Hat Developer Toolset 1 1 Below is a comprehensive list of new features in this release A 8 1 Changes Since Red Hat Developer Toolset 1 1 The following features have been added since the release of SystemT ap included in Red Hat Developer Toolset 1 1 SystemTap has been updated to provide experimental support for Dyninst based probing in the user space Users can now execute the stap utility with the dyninst command line option to instrument their own programs without the need to acquire root privileges SystemT ap is now distributed with a number of manual pages that provide a detailed explanation of common errors The error buildid stap manual page documents build id verification failures The error dwarf 7stap manual page documents common DWARF debuginfo quality problems The error fault 7stap manual page documents memory access faults The error inode uprobes 7stap manual page documents current limitations of inode uprobes 133 Red Hat Developer Toolset 2 x User Guide The error passi1 7stap manual page documents pass 1 parsing
34. 068 1790 35 total 8 3 Additional Resources A detailed description of strace and its features is beyond the scope of this book For more information see the resources listed below Installed Documentation 59 Red Hat Developer Toolset 2 x User Guide strace 1 The manual page for the strace utility provides detailed information about its usage To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 2 man strace See Also 60 with overlapping memory regions that are not allowed by various standards Chapter 9 memstomp Chapter 9 memstomp memstomp is a command line tool that can be used to identify function calls with overlapping memory regions in situations when such an overlap is not permitted by various standards It intercepts calls to overlap it displays a detailed backtrace to help you debug the problem Similarly to Valgrind the memstomp utility inspects applications without the need to recompile them However it is much faster than this tool and therefore serves as a convenient alternative to it Red Hat Developer Toolset is distributed with memstomp 0 1 4 61 Red Hat Developer Toolset 2 x User Guide Table 9 1 Function Calls Inspected by memstomp Function Description memcpy Copies n bytes from one memory area to another and returns a pointer to the second memory area memccpy Copies a maximum of n bytes from one memory area to another a
35. 15 3 The Connect Menu The Connect menu allows you to connect to the industry s best engineers and collaborate with industry peers This includes Knowledgebase The Knowledgebase contains a large number of whitepapers on a variety of topics which can serve as another source of documentation for your project Note that the Knowledgebase section requires you to enter your Red Hat login and password Groups This section allows users to join a group to collaborate on the documents They can also create and comment on discussions to interact with other customers Red Hat support staff and certified engineers Note that the Groups section requires you to enter your Red Hat login and password Videos A number of videos on how to get vital solutions useful tips product demonstrations and inside information can be accessed from here You can also rate and comment on all of the videos 87 88 Red Hat Developer Toolset 2 x User Guide Tech Briefs Tech briefs provide practical advice to help solve real world problems with Red Hat products Each tech brief provides a detailed use case covering best practices how to instructions or detailed discussions on how to use Red Hat technology effectively and are reviewed and tested by Red Hat engineers Source This is the kernel source browser and contains links to all the kernel sources broken into each individual patch unlike the kernel srpm which is shipped as one big patch Note that the
36. 2 Using strace 32 33 34 34 34 35 36 36 36 36 38 38 39 40 40 41 41 41 42 42 42 43 43 44 44 44 44 45 46 47 47 47 47 48 48 49 51 51 51 51 52 52 53 54 54 54 56 56 56 Table of Contents 8 2 1 Redirecting Output to a File 8 2 2 Tracing Selected System Calls 8 2 3 Displaying Time Stamps 8 2 4 Displaying a Summary 8 3 Additional Resources Installed Documentation See Also Chapter 9 memstomp uS ai Sie GS e BS Mate MON UA a ee 9 1 Installing memstomp 9 2 Using memstomp 9 3 Additional Resources Installed Documentation See Also Part V Performance Monitoring T 0018 Chapter LO cSystemT aps oet ERE REP neice dk beck eee ES use e Ro een e ttem UR RS 10 1 Installing SystemT ap 10 2 Using SystemT ap 10 3 Additional Resources Installed Documentation Online Documentation See Also Ghapter 11 Valgrind cupi ei o bct tttm fl 11 1 Installing Valgrind 11 2 Using Valgrind 11 3 Additional Resources Installed Documentation Online Documentation See Also Chapter12 OProfile ss 222 0006 tel dea dX de iua ea ina id ela 12 1 Installing OProfile 12 2 Using OProfile 12 3 Additional Resources Installed Documentation Online Documentation See Also Chapter 13 Dyhlnst toris won Era etti NC cR ette de Rs WR dp BA a a Rd a aa 13 1 Installing Dyninst 13 2 Using Dyninst 13 2 1 Using Dyninst with SystemT ap 13 22 Using Dyninst as a Stand alone Application 13 3 Addi
37. BMI2 and LZCNT march bdver2 and mtune bdver2 Optimization for AMD Opteron processors code named Piledriver march btver1 and mtune btver1 Optimization for AMD family 14 processors code named Bobcat march bdver1 and mtune bdver1 Optimization for AMD family 15h processors code named Bulldozer Support for various processor specific intrinsics and instructions is now available through the command Table A 2 Support for Processor specific Intrinsics and Instructions mavx2 Support for Intel AVX2 intrinsics built in functions and code generation mbmi2 Support for Intel BMI2 intrinsics built in functions and code generation mlzcnt Implementation and automatic generation of builtin clz using the lzcnt instruction mfma Support for Intel FMA3 intrinsics and code generation mfsgsbase Enables the generation of new segment register read write instructions through dedicated built ins mrdrnd Support for the Intel rdrnd instruction mf16c Support for two additional AVX vector conversion instructions mtbm Support for TBM Trailing Bit Manipulation built in functions and code generation mbmi Support for AMD s BMI Bit Manipulation built in functions and code generation mcrc32 Support for crc32 intrinsics mmovbe Enables the use of the movbe instruction to implement builtin bswap32 and builtin bswap64 mxop mfma4 and Support for the XOP FMA4 and LWP instruction sets for the AMD Orochi mlwp proce
38. Enterprise Linux 6 4 The following features have been added since the release of binutils included in Red Hat Enterprise Linux 6 4 The GNU Assembler no longer requires double ampersands in macros A new compress debug sections command line option has been added to enable compression of DWARF debug information sections in the relocatable output file Compressed debug sections are currently supported by the readelf objdump and gold tools but not by 1d Support for bundle align mode bundle lock and bundle unlock directives for x86 targets has been added On x86 architectures the GNU Assembler now allows rep bsf rep bsr andrep ret syntax Changes Since Red Hat Enterprise Linux 5 9 The following features have been added since the release of binutils included in Red Hat Enterprise Linux 5 9 GNU Linux targets now support gnu unique object as a value of the type pseudo operation This value can be used to mark a symbol as globally unique in the entire process Support for the new discriminator column in the DWARF line table with a discriminator operand for the loc directive has been added The type pseudo operation now accepts a type of STT GNU IFUNC This can be used to indicate that if the symbol is the target of a relocation its value should not be used Instead the function should be invoked and its result used as the value A new pseudo operation cfi val encoded addr has been added This pseudo operation can be used to
39. GCHECK OPTIONS section of the valgrind 1 manual page has been corrected and no longer includes the BBV options As well the BBV options are now listed in a separate section A 10 2 Changes Since Red Hat Enterprise Linux 5 9 In addition to the above changes the following features have been added since the release of Valgrind 3 5 0 included in Red Hat Enterprise Linux 5 9 When running in 64 bit mode Valgrind now supports the SSEA 2 instruction set with the exception of SSEA 2 AES instructions In 32 bit mode Valgrind only provides support up to and including the SSSE3 instruction set A new processing script cg diff has been added to Cachegrind This processing script can find the difference between two profiles and can therefore be used to evaluate the performance effects of a change in a program The behavior of the cg annotate s rarely used threshold option has been changed Callgrind now supports branch prediction simulation and can optionally count the number of executed global bus events Note that in order to use this functionality for a better approximation of a Cycle Estimation as a derived event you must manually update the event formula in KCachegrind To accommodate machines with three levels of caches both Cachegrind and Callgrind now refer to the LL last level cache rather than the L2 cache When Cachegrind or Callgrind auto detects the cache configuration of such a machine it now runs the simulation as if the L2 cach
40. IDs unique numbers to identify executables Support for the IFUNC and UNIQUE symbols that are used by glibc to improve performance Due to dependencies on a particular version of the glibc library these symbols are only available on Red Hat Enterprise Linux 6 Compressed debug sections for smaller debug info files 1 3 Compatibility Red Hat Developer Toolset 2 0 is available for Red Hat Enterprise Linux 5 and 6 both for 32 bit and 64 illustrates the support for binaries built with Red Hat Developer Toolset on a certain version of Red Hat Enterprise Linux when those binaries are run on various other versions of this system 15 Red Hat Developer Toolset 2 x User Guide Run on 5 10 5 11 6 0 EUS 6 1EUS 62EUS 6 3 EUS Unsupported version of Red Hat Enterprise Linux host 59 o O O 00 00 00 5 10 oO 0000 00 00 E oO 0000 00 00 Oo 6 0 EUS Unsupported version of Red Hat Enterprise Linux host 6 1 EUS Unsupported version of Red Hat Enterprise Linux host eus 090 O O O O 0O Q ses O O O O O O 8 O0 6 4 O 8 O O 6 O 8 8 0 9G 6 5 O 8 O O 0 8 8 9 9 3 Unsupported Supported Figure 1 1 Red Hat Developer Toolset 2 0 Compatibility Matrix 1 4 Getting Access to Red Hat Developer Toolset Red Hat Developer Toolset is an offering that is distributed as part of the developer subscriptions listed management service with which you registered your Red Hat Enterprise Linux system you can either enab
41. PRIVATE MAP_ANONYMOUS 1 0 0x7f896c744000 mmap NULL 61239 PROT READ MAP PRIVATE 3 0 0x7f896c735000 mmap 0x3146a00000 3745960 PROT READ PROT EXEC MAP PRIVATE MAP DENYWRITE 3 0 0x3146a00000 mmap 0x3146d489000 20480 PROT READ PROT WRITE MAP PRIVATE MAP FIXED MAP DENYWRITE 3 0x189000 0x3146d89000 mmap 0x3146d8e000 18600 PROT READ PROT WRITE MAP PRIVATE MAP FIXED MAP ANONYMOUS 1 0 0x3146d8e000 mmap NULL 4096 PROT READ PROT WRITE MAP PRIVATE MAP ANONYMOUS 1 0 0x7f896c734000 mmap NULL 4096 PROT READ PROT WRITE MAP_PRIVATE MAP_ANONYMOUS 1 0 0x7f896c733000 mmap NULL 4096 PROT READ PROT WRITE MAP_PRIVATE MAP_ANONYMOUS 1 0 0x7f896c732000 munmap 0x7f896c735000 61239 0 mmap NULL 4096 PROT READ PROT WRITE MAP_PRIVATE MAP_ANONYMOUS 1 0x7f896c743000 John john example comDoe exited with 0 8 2 3 Displaying Time Stamps To prefix each line of the trace with the exact time of the day in hours minutes and seconds run the strace utility with the t command line option scl enable devtoolset 2 strace t program argument To also display milliseconds supply the t option twice scl enable devtoolset 2 strace tt program argument To prefix each line of the trace with the time required to execute the respective system call use the r command line option scl enable devtoolset 2 strace r program argument 58 Example 8 3 Displaying Ti
42. Program on the Command Line Consider a source file named hello cpp with the following contents E C include lt iostream gt using namespace std int main int argc char argv cout lt lt Hello World lt lt endl return 0 Jj lt S To compile this source code on the command line by using the g compiler from Red Hat Developer Toolset type WE _ scl enable devtoolset 2 g o hello hello cpp SS This creates a new binary file called hello in the current working directory 3 2 3 Running a C Program When g compiles a program it creates an executable binary file To run this program on the command line change to the directory with the executable file and type p SS file name NE Red Hat Developer Toolset 2 x User Guide Example 3 4 Running a C Program on the Command Line hello Hello World 3 3 GNU Fortran Compiler 3 3 1 Installing the Fortran Compiler In Red Hat Developer Toolset the GNU Fortran compiler is provided by the devtoolset 2 gcc gfortran 3 3 2 Using the Fortran Compiler To compile a Fortran program on the command line run the gfortran compiler as follows scl enable devtoolset 2 gfortran o output_file source_file This creates a binary file named output_file in the current working directory If the o option is omitted the compiler creates a file named a out by default When you
43. Red Hat Developer Toolset may use a later major release of GCC forward compatibility of objects binaries and libraries built with the std c 11 or std gnu 11 options cannot be guaranteed and so is not supported The default language standard setting for Red Hat Developer Toolset is C 98 Any C 98 compliant binaries or libraries built in this default mode or explicitly with std c 98 can be freely mixed with binaries and shared libraries built by the Red Hat Enterprise Linux 5 or 6 system toolchain GCC Red Hat recommends use of this default std c 98 mode for production software development OP important Use of C 11 features in your application requires careful consideration of the above ABI compatibility information Developer Toolset with those built with the Red Hat Enterprise Linux v5 x v6 x toolchain particularly o a files the Red Hat Developer Toolset toolchain should be used for any linkage This ensures any newer library features provided only by Red Hat Developer Toolset are resolved at link time A new standard mangling for SIMD vector types has been added to avoid name clashes on systems with 114 Changes in Version 2 0 vectors of varying length By default the compiler still uses the old mangling but emits aliases with the new mangling on targets that support strong aliases Wabi will now display a warning about code that uses the old mangling A 2 2 3 2 Miscellaneous GCC now optimizes calls to vari
44. This warning is enabled by Wall and may be avoided by using a type cast Casting integers to larger pointer types now causes GCC to display a warning by default To disable these warnings use the Wno int to pointer cast option which is available for both C and C Conversions between NULL and non pointer types now cause GCC to report a warning by default Previously these warnings were only displayed when explicitly using Wconversion To disable these warnings use the new Wno conversion null command line option GCC can now warn when a class that has virtual functions and a non virtual destructor is destroyed by using delete This is unsafe to do because the pointer might refer to a base class that does not have a virtual destructor The warning is enabled by Wall and by a new command line option Wdelete non virtual dtor New Wc 11 compat and Wc 0x compat options are now available These options cause GCC to display a warning about C constructs whose meaning differs between ISO C 1998 and ISO C 2011 such as identifiers in ISO C 1998 that are keywords in ISO C 2011 This warning is enabled by Wall and enables the Wnarrowing option A 2 2 2 4 Fortran A 2 2 2 4 1 New Features A new compile flag fstack arrays has been added This flag causes all local arrays to be put on stack memory which can significantly improve the performance of some programs Note that programs that use very large local arrays may require you
45. User Guide Chapter 4 binutils binutils is a collection of various binary tools such as the GNU linker GNU assembler and other Red Hat Developer Toolset version of binutils Red Hat Developer Toolset is distributed with binutils 2 23 52 This version is more recent than the version included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements including the new gold linker several new command line options improvements to the linker script language and support for link time optimization compressed debug sections and new instruction sets For a detailed list of changes see Section A 3 Changes in binutils Table 4 1 Tools Included in binutils for Red Hat Developer Toolset Name Description addr2line Translates addresses into file names and line numbers ar Creates modifies and extracts files from archives as The GNU assembler c filt Decodes mangled C symbols dwp Combines DWARF object files into a single DWARF package file elfedit Examines and edits ELF files gprof Display profiling information ld The GNU linker ld bfd An alternative to the GNU linker ld gold A new ELF linker nm Lists symbols from object files objcopy Copies and translates object files objdump Displays information from object files ranlib Generates an index to the contents of an archive to make access to this archive faster readelf Displays information about ELF files size Lists section sizes of object
46. Valgrind 3 8 1 This version is more recent than the version included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements Table 11 1 Tools Distributed with Valgrind for Red Hat Developer Toolset Name Description Memcheck Detects memory management problems by intercepting system calls and checking all read and write operations Cachegrind Identifies the sources of cache misses by simulating the level 1 instruction cache I1 level 1 data cache D1 and unified level 2 cache L2 Callgrind Generates a call graph representing the function call history Helgrind Detects synchronization errors in multithreaded C C and Fortran programs that use POSIX threading primitives DRD Detects errors in multithreaded C and C programs that use POSIX threading primitives or any other threading concepts that are built on top of these POSIX threading primitives Massif Monitors heap and stack usage 11 1 Installing Valgrind In Red Hat Developer Toolset Valgrind is provided by the devtoolset 2 valgrind package and is automatically installed with devtoolset 2 perftools If you intend to use Valgrind to profile parallel programs that use the Message Passing Interface MPI protocol also install the devtoolset 2 valgrind openmpi package by typing the following at a shell prompt as root yum install devtoolset 2 valgrind openmpi For detailed instructions on how to install Red Hat Developer Toolset and related packages
47. ables built with the Red Hat Developer Toolset toolchain can then also be deployed and run on multiple versions of Red Hat Critically Red Hat Developer Toolset does not replace the default system tools provided with Red Hat Enterprise Linux 5 or 6 when installed on those platforms Instead a parallel set of developer tools provides an alternative newer version of those tools for optional use by developers The default compiler and debugger for example remain those provided by the base Red Hat Enterprise Linux system Table 1 1 Red Hat Developer Toolset Components Name Version Description Eclipse 4 3 0 An integrated development environment for the graphical user interface al GCC 4 8 1 A portable compiler suite with support for C C and Fortran binutils 2 23 52 A collection of binary tools and other utilities to inspect and manipulate object files and binaries elfutils 0 155 A collection of binary tools and other utilities to inspect and manipulate ELF files dwz 0 11 A tool to optimize DWARF debugging information contained in ELF shared libraries and ELF executables for size GDB 7 6 A command line debugger for programs written in C C and Fortran strace 4 7 A debugging tool to monitor system calls that a program uses and signals it receives memstomp 0 1 4 A debugging tool to identify calls to library functions with overlapping memory regions that are not allowed by various standards SystemT ap 2 1 A tracing and probi
48. al sizeof int fprintf stderr Function executed d times n val li BPatch bpatch int main int argc char argv int pid if argc 3 usage exit 1 pid atoi argv 1 79 Red Hat Developer Toolset 2 x User Guide BPatch_process app bpatch processAttach NULL pid if app exit 1 BPatch_image appImage app gt getImage createCounter app appImage fprintf stderr Finding function s argv 2 BPatch_Vector lt BPatch_function gt countFuncs fprintf stderr OK nInstrumenting function s argv 2 interceptfunc app appImage argv 2 bpatch registerExitCallback printCount fprintf stderr OK nwaiting for process d to exit n pid app gt continueExecution while app gt isTerminated bpatch waitForStatusChange return 0 This program accepts a process ID and a function name as command line arguments and then prints the total number of times the function was called during the execution of the process You can use the following Makefile to build these two files DTS opt rh devtoolset 2 root CXXFLAGS g I DTS usr include dyninst LBITS shell getconf LONG_BIT ifeq LBITS 64 DYNINSTLIBS DTS usr lib64 dyninst else DYNINSTLIBS DTS usr lib dyninst endif PHONY all all count exercise count count C g CXXFLAGS count C I usr include dyninst c g CXXFLAGS count o L DYNINSTLIBS ldyninstAPI o count ex
49. al Public License version 3 A 3 1 GNU Linker Another ELF linker gold is now available in addition to 1d the existing GNU linker gold is intended to be a drop in replacement for 1d so 1d s documentation is intended to be the reference documentation gold supports most of 1d s features except notable ones such as MRI compatible linker scripts cross reference reports cref and various other minor options It also provides significantly improved link time with very large C applications In Red Hat Developer Toolset 2 0 the gold linker is not enabled by default Users can explicitly switch between 1d and gold by using the alternatives mechanism A 3 1 1 New Features Changes Since Red Hat Enterprise Linux 6 4 The following features have been added since the release of binutils included in Red Hat Enterprise Linux 6 4 A new INPUT SECTION FLAGS keyword has been added to the linker script language This keyword can be used to select input sections by section header flags A new SORT BY INIT PRIORITY keyword has been added to the linker script language This keyword can be used to sort sections by numerical value of the GCC init priority attribute encoded in the section name A new SORT NONE keyword has been added to the linker script language This keyword can be used to disable section sorting A new linker provided symbol ehdr_start has been added When producing ELF output this symbol points to the ELF file header and
50. always preserve data race freedom when optimizing code GCC also supports new built ins for atomic memory accesses which follow the design of the memory model and new atomic operations The former set of synchronization built ins that is those prefixed with __ sync are still supported Transactional Memory Transactional Memory TM allows programs to declare that a piece of code is supposed to execute as a transaction that is virtually atomically and in isolation from other transactions GCC s transactional memory runtime library Libitm then ensures this atomicity guarantee when executing the compiled program Compared to atomic memory accesses it is a higher level programming abstraction because it is not limited to single memory locations does not require special data types for the data it modifies and because transactions can contain arbitrary code and be nested within other transactions with some 101 Red Hat Developer Toolset 2 x User Guide restrictions explained subsequently already supports a C compatible subset of the constructs when compiling C source code The main language constructs are transaction statements and expressions and are declared by the transaction atomicor transaction relaxed keywords followed by a compound statement or expression respectively The following example illustrates how to increment a global variable y if another variable x has a value less than 10 transaction atomic if x lt 10
51. and line option Additionally GNU Fortran now provides preliminary support for multiple images via an MPI based coarray communication library Note that the library version is not yet usable as remote coarray access is not yet possible The STOP and ERROR STOP statements have been updated to support all constant expressions The CONT IGUOUS attribute is now supported Use of ALLOCATE with the MOLD argument is now supported The STORAGE SIZE intrinsic inquiry function is now supported The NORM2 and PARITY intrinsic functions are now supported The following bit intrinsics have been added the POPCNT and POPPAR bit intrinsics for counting the number of 1 bits and returning the parity the BGE BGT BLE and BLT bit intrinsics for bitwise comparisons the DSHIFTL and DSHIFTR bit intrinsics for combined left and right shifts the MASKL and MASKR bit intrinsics for simple left and right justified masks the MERGE_BITS bit intrinsic for a bitwise merge using a mask the SHIFTA SHIFTL and SHIFTR bit intrinsics for shift operations the transformational bit intrinsics IALL IANY and IPARITY The EXECUTE_COMMAND_LINE intrinsic subroutine is now supported The IMPURE attribute for procedures is now supported This allows the use of ELEMENTAL procedures without the restrictions of PURE Null pointers including NULL and unallocated variables can now be used as an actual argument to optional non pointer non allocatable dummy arguments denoting an absen
52. andard C library include files have been edited to no longer include lt cstddef gt to get namespace std scoped versions of size_t and ptrdiff t As such C programs that used the 106 Changes in Version 2 0 macros NULL or of fsetof without including lt cstddef gt will no longer compile The diagnostic produced is similar to the following error ptrdiff t does not name a type error size t has not been declared error NULL was not declared in this scope error there are no arguments to offsetof that depend on a template parameter so a declaration of offsetof must be available To fix this issue add the following line include lt cstddef gt Name Lookup Changes G no longer performs an extra unqualified lookup that it incorrectly performed in the past Instead it implements the two phase lookup rules correctly and an unqualified name used in a template must have an appropriate declaration that 1 is either in scope at the point of the template s definition or 2 can be found by argument dependent lookup at the point of instantiation Code that incorrectly depends on a second unqualified lookup at the point of instantiation such as finding functions declared after the template or in dependent bases will result in compile time errors In some cases the diagnostics provided by G include hints how to fix the bugs Consider the following code template lt typename T int t T i return f i j in
53. ands control automatic loading of GDB scripts The set auto load python scripts and show auto load python scripts commands control automatic loading of Python scripts The set auto load local gdbinit and show auto load local gdbinit commands control automatic loading of gdbinit from the current working directory The set auto load libthread db and show auto load libthread db commands control automatic loading of inferior specific 13bthread db The set auto load scripts directory and show auto load scripts directory commands control the list of directories from which to automatically load GDB and Python scripts The set auto load safe path and show auto load safe path commands control the list of directories from which it is safe to automatically load all previously mentioned items The set debug auto load and show debug auto load commands control displaying of debugging information for all previously mentioned items The set auto load off command can be used to disable automatic loading globally You can also use show auto load with no subcommand to display current settings of all previously mentioned items Themaint set python auto load on off command has been replaced with set auto load python scripts on off The maintenance print section scripts command has been renamed to info auto load python scripts pattern and is no longer classified as a maintenance only command Support for the Guile extension language has been removed The GNU Deb
54. anges Name Lookup Changes Uninitialized const Visibility of Template Instantiations User defined Literal Support Taking the Address of Temporary Miscellaneous A 2 2 2 3 C C Warnings A 2 2 2 4 Fortran A 2 2 2 4 1 New Features A 2 2 2 4 2 Compatibility Changes A 2 2 2 4 3 Fortran 2003 Features A 2 2 2 4 4 Fortran 2003 Compatibility A 2 2 2 4 5 Fortran 2008 Features A 2 2 2 4 6 Fortran 2008 Compatibility A 2 2 2 4 7 Fortran 77 Compatibility A 2 2 3 ABI Compatibility A 2 2 3 1 C ABI A 2 2 3 2 Miscellaneous A 2 2 4 Debugging Compatibility A 2 2 5 Other Compatibility A 3 Changes in binutils A 3 1 GNU Linker A 3 1 1 New Features Changes Since Red Hat Enterprise Linux 6 4 Changes Since Red Hat Enterprise Linux 5 9 A 3 1 2 Compatibility Changes Changes Since Red Hat Enterprise Linux 6 4 Changes Since Red Hat Enterprise Linux 5 9 A 3 2 GNU Assembler A 3 2 1 New Features Changes Since Red Hat Enterprise Linux 6 4 Changes Since Red Hat Enterprise Linux 5 9 A 3 3 Other Binary Tools A 3 3 1 New Features Changes Since Red Hat Developer Toolset 1 1 Changes Since Red Hat Enterprise Linux 6 4 Changes Since Red Hat Enterprise Linux 5 9 Table of Co ntents 100 100 100 100 100 100 100 101 101 101 103 105 105 106 106 106 106 106 107 108 108 108 109 109 109 110 110 111 112 112 113 114 114 114 114 115 115 115 115 116 116 116 116 117 117 117 118 118 118 118 119 119 119 119 119
55. are working on a project that consists of several source files it is common to compile an object file for each of the source files first and then link these object files together This way when you change a single source file you can recompile only this file without having to compile the entire project To compile an object file on the command line run the following command scl enable devtoolset 2 gfortran o object file c source file This creates an object file named object_file If the o option is omitted the compiler creates a file named after the source file with the o file extension To link object files together and create a binary file run scl enable devtoolset 2 gfortran o output file object file Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset gfortran as default scl enable devtoolset 2 bash 34 Chapter 3 GNU Compiler Collection GCC rraauA To verify the version of gfortran you are using at any point type the following at a shell prompt which gfortran Red Hat Developer Toolset s gfortran executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset gfortran
56. arted void xend void Commits the current transaction When no transaction is active this function causes a fault All memory side effects of the transactions become visible to other threads in an atomic manner int _xtest void Returns a non zero value if a transaction is currently active or zero if it is not void xabort unsigned char status Aborts the current transaction When no transaction is active this is a no op The parameter status is included in the return value of any xbegin call that is aborted by this function The following example illustrates the use of these intrinsics 99 Red Hat Developer Toolset 2 x User Guide if status _xbegin _XBEGIN_STARTED some code _xend else examine the status to see why the transaction failed and possibly retry Transactions Using Transactional Synchronization Extensions Transactions in the transactional memory feature the fgnu tm option of GCC can now be run using Transactional Synchronization Extensions T SX if available on x86 hardware Support for AMD Family 15h Processors The x86 backend of GCC now supports CPUs based on AMD Family 15h cores with the 64 bit x86 instruction set support This can be enabled by using the march bdver3 option Support for AMD Family 16h Processors The x86 backend of GCC now supports CPUs based on AMD Family 16h cores with the 64 bit x86 instruction set support This can be enabled by using the
57. ation Inc License GPLv3 GNU GPL version 3 or later http gnu org licenses gpl html This is free software you are free to change and redistribute it There is NO WARRANTY to the extent permitted by law Type show copying and show warranty for details This GDB was configured as x86 64 redhat linux gnu For bug reporting instructions please see http www gnu org software gdb bugs gdb 7 4 Listing Source Code To view the source code of the program you are debugging run the following command 49 Red Hat Developer Toolset 2 x User Guide list Before you start the execution of the program you are debugging gdb displays first ten lines of the source code and any subsequent use of this command lists another ten lines Once you start the execution gdb displays the lines that are surrounding the line on which the execution stops typically when you set a breakpoint You can also display the code that is surrounding a particular line To do so run the command in the following form list file name line number Similarly to display the code that is surrounding the beginning of a particular function run list file name function name Note that you can change the number of lines the List command displays by running the following command set listsize number Example 7 4 Listing the Source Code of the fibonacci Binary File has exactly 17 lines Assuming that you have compiled it with debugging infor
58. bles for size To do so dwz replaces DWARF information representation with equivalent smaller representation where possible and reduces the amount of duplication by using techniques from Appendix E of the DWARF Standard Red Hat Developer Toolset is distributed with dwz 0 11 6 1 Installing dwz In Red Hat Developer Toolset the dwz utility is provided by the devtoolset 2 dwz package and is 6 2 Using dwz To optimize DWARF debugging information in a binary file run the dwz tool as follows scl enable devtoolset 2 dwz option file_name Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset dwz as default scl enable devtoolset 2 bash K To verify the version of dwz you are using at any point type the following at a shell prompt which dwz Red Hat Developer Toolset s dwz executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset dwz dwz v 6 3 Additional Resources A detailed description of dwz and its features is beyond the scope of this book For more information see the resources listed below Installed Documentation dwz 1 The manual page for the dwz utility provides detailed information on
59. bug notification commands have been added These commands allow you to control whether to display debugging information for asynchronous remote notification This functionality is disabled by default New convenience functions memeq buf1 buf2 length _streq stri str2 strlen str and regex str regex have been added The following changes have been made to the Python scripting support since the release of GDB included in Red Hat Developer Toolset 1 1 Users can now create vectors by using the gdb Type vector method The atexit register method is now supported Users can now pretty print types by using the Python API In addition to Python 2 4 and later GDB now also supports Python 3 A new class gdb Architecture has been added This class exposes the internal representation of the architecture in the Python API A new method Frame architecture has been added This method can be used to return the gdb Architecture object corresponding to the frame s architecture Frame filters and frame decorators have been added The following MI changes have been made since the release of GDB included in Red Hat Developer Toolset 1 1 A new async record cmd param changed has been added This async record reports that a command parameter has changed A new async record traceframe changed has been added This async record reports that a trace frame has been changed by using the tf ind command New async records tsv create
60. can be used to set individual permissions for the target A new command main info program spaces has been added This command can be used to display information about currently loaded program spaces New commands set remote interrupt sequence and show remote interrupt sequence have been added The set remote interrupt sequence command accepts Ctr1 C BREAK and BREAK g as valid arguments and can be used to specify which interrupt sequence to send to the remote target in order to interrupt its execution Use the show remote interrupt sequence to determine the current setting New commands set remote interrupt on connect and show remote interrupt on connect have been added The set remote interrupt on connect accepts either on or off as an argument and can be used to enable sending an interrupt sequence to the remote target when the GNU Debugger connects to it Use the show remote interrupt on connect command to determine whether this feature is enabled The set remotebreak and show remotebreak commands have been deprecated and users are advised to use set remote interrupt sequence and show remote interrupt sequence instead The disassemble command has been adapted to accept two arguments in the form of start length The source command can now be used to read commands from Python scripts The following changes have been made to the C language support since the release of the GNU Debugger included in Red Hat Enterprise Linux 5 8 Arg
61. ccess to the repository for Red Hat Developer Toolset and then enable that repository Red Hat Developer Toolset 2 x User Guide 1 Display a list of all subscriptions that are available for your system to determine the pool ID of a subscription that provides Red Hat Developer Toolset To do so type the following at a shell prompt as root subscription manager list available For each available subscription this command displays its name unique identifier expiration date and other details related to your subscription The pool ID is listed on a line beginning with Pool Id For a complete list of subscriptions that provide access to Red Hat Developer Toolset see 2 Attach the appropriate subscription to your system by running the following command as root subscription manager subscribe pool pool_id Replace pool id with the pool ID you determined in the previous step To verify the list of subscriptions your system has currently attached at any time run as root subscription manager list consumed 3 Display a list of available Yum repositories to retrieve repository metadata and to determine the exact name of the Red Hat Developer Toolset repositories As root type yum repolist all The repository names depend on the specific version of Red Hat Enterprise Linux you are using and are in the following format rhel variant dts2 version rpms rhel variant dts2 version debug rpms rhel variant dts2 version source rpms R
62. cessor For a complete list of valid CPU names see the user manual A new built in function builtin cpu supports has been added to detect if the run time CPU supports a particular ISA feature This function accepts one string literal argument with the ISA feature and returns a positive integer on a match and zero otherwise For example _ builtin cpu supports ssse3 returns a positive integer if the run time CPU supports SSSE3 instructions For a complete list of valid ISA names see the user manual PP important If these built in functions are called before any static constructors are invoked such as IFUNC initialization then the CPU detection initialization must be explicitly run using this newly provided built in function _builtin_cpu_init The initialization needs to be done only once For example the following is sample invocation inside an IFUNC initializer static void some ifunc resolver void void __builtin_cpu_init if __builtin_cpu_is amdfami0h if _builtin cpu supports popent Function Multiversioning Function multiversioning allows the programmer to specify multiple versions of the same function each of which is specialized for a particular variant of a given target At runtime the appropriate version is automatically executed depending upon the target where the execution takes place For example consider the following code fragment __attribute__ target default int
63. changes 2 3 Additional Resources A detailed description of Eclipse and all its features is beyond the scope of this book For more information see the resources listed below Installed Documentation Eclipse includes a built in Help system which provides extensive documentation for each integrated feature and tool This greatly decreases the initial time investment required for new developers to become fluent in its use The use of this Help section is detailed in the Red Hat Enterprise Linux Developer Guide linked below Online Documentation provides more information on Eclipse including a description of the user interface overview of available development toolkits or instructions on how to use it to build RPM packages See Also 28 in C C and Fortran on the command line Part Ill Development Tools Part Ill Development Tools 29 Red Hat Developer Toolset 2 x User Guide Chapter 3 GNU Compiler Collection GCC The GNU Compiler Collection commonly abbreviated GCC is a portable compiler suite with support for a wide selection of programming languages Red Hat Developer Toolset is distributed with GCC 4 8 This version is more recent than the version included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements including optimization for various new Intel and AMD processors support for OpenMP 3 1 and link time optimization This version also includes experimental support for the C 11 s
64. cope applicability and complexity of runtime support C 11 Types and GCC Built ins for Atomic Memory Access C 11 has support for atomic types Access to memory locations of this type is atomic and appears as one indivisible access even when other threads access the same memory location concurrently The atomicity is limited to a single read or write access or one of the other atomic operations supported by such types for example two subsequent operations executed on a variable of atomic type are each atomic separately but do not form one joint atomic operation An atomic type is declared as atomic lt T gt where T is the non atomic base type and must be trivially copyable for example atomic lt int gt is an atomic integer GCC does not yet support any base type T but only those that can be accessed atomically with the atomic instructions offered by the target architecture This is not a significant limitation in practice given that atomics are primarily designed to expose hardware primitives in an architecture independent fashion pointers and integrals that are not larger than a machine word on the target are supported as base types Using base types that are not yet supported results in link time errors The code generated for operations on atomic types including the memory orders implements the semantics specified in the C 11 standard However support for the C 11 memory model is still experimental and for example GCC might not
65. ct id refresh packagekit subscription manager gt Running transaction check gt Package glibc debuginfo x86_64 0 2 12 1 47 e16 2 5 will be installed 7 3 Running the GNU Debugger 48 Chapter 7 GNU Debugger GDB To run the GNU Debugger on a program you want to debug type the following at a shell prompt scl enable devtoolset 2 gdb file_name This starts the gdb debugger in interactive mode and displays the default prompt gdb To quit the debugging session and return to the shell prompt run the following command at any time quit Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset gdb as default scl enable devtoolset 2 bash K rra To verify the version of gdb you are using at any point type the following at a shell prompt which gdb Red Hat Developer Toolset s gdb executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset gdb gdb v Example 7 3 Running the gdb Utility on the fibonacci Binary File the following at a shell prompt scl enable devtoolset 2 gdb fibonacci GNU gdb GDB Red Hat Enterprise Linux 7 4 50 20120120 43 e16 Copyright C 2012 Free Software Found
66. d tsv deleted and tsv modified have been added These async records report that a trace state variable has been created deleted or modified New async records record started and record stopped have been added These async records report that a process record has been started or stopped A new async record memory changed has been added This async record reports that the memory has changed When the source is requested the data disassemble command now includes a new fullname field containing an absolute path to the source file name A new optional parameter COUNT has been added to the data write memory bytes command This parameter can be used to allow pattern filling of memory areas New commands catch load and catch unload have been added These commands can be used to intercept shared library load unload events The response to breakpoint commands and breakpoint async records now includes a new installed field This field reports the current state of each non pending tracepoint location when the tracepoint is installed the value of this field is y otherwise the value is n The output of the trace status command now includes a new trace file field This field is only present when examining a trace file and contains the name of this file The fullname filed is now always present along with the file field This field is included even if GDB cannot find the file A number of new remote packets have been added since the
67. d by the devtoolset 2 dyninst package and provided by the devtoolset 2 toolchain package If you intend to write a custom instrumentation for binaries install the relevant header files by running the following command as root yum install devtoolset 2 dyninst devel You can also install API documentation for this library by typing the following at a shell prompt as root yum install devtoolset 2 dyninst doc For a complete list of documents that are included in the devtoolset 2 dyninst doc package see 13 2 Using Dyninst 13 2 1 Using Dyninst with SystemTap To use Dyninst along with SystemT ap to allow non root users to instrument user space executables run the stap command with the dyninst or runtime dyninst command line option This tells stap to translate a SystemT ap script into C code that uses the Dyninst library compile this C code into a shared library and then load the shared library and run the script Note that when executed like this the stap command also requires the c or x command line option to be specified To use the Dyninst runtime to instrument an executable file type the following at a shell prompt scl enable devtoolset 2 stap dyninst c command option argument Similarly to use the Dyninst runtime to instrument a user s process type scl enable devtoolset 2 stap dyninst x process id option argument SystemT ap For a general introduction to SystemT ap and its usage see the Sys
68. d disable type printer name commands have been added These commands allow you to enable or disable type printers New set print type methods on off and show print type methods commands have been added These commands allow you to control whether method declarations are displayed by the ptype command This functionality is enabled by default New set print type typedefs on off and show print type typedefs commands have been added These commands allow you to control whether typedef definitions are displayed by the ptype command This functionality is enabled by default New set filename display basename relative absolute and show filename display commands have been added These commands allow you to control the way in which file names are displayed the basename option displays only the base name of a file name relative displays a path relative to the compilation directory and absolute displays an absolute path to the file The default option is relative to preserve the previous behavior New set trace buffer size and show trace buffer size commands have been added These commands allow you to control the size of the trace buffer for a target New set remote trace buffer size packet auto on off and show remote trace buffer size packet commands have been added These commands allow you to control the 123 Red Hat Developer Toolset 2 x User Guide use of the remote protocol QTBuf fer size packet New set debug notification and show de
69. d in Red Hat Developer Toolset 1 1 A new command line utility operf has been added This utility can be executed by a non root user and can be used to collect profiling data Pr important NN The oper f utility relies on a kernel feature that is currently not available in Red Hat Enterprise Linux 5 Consequently this utility only works and is supported on Red Hat Enterprise Linux 6 OProfile now supports Intel processors code named lvy Bridge A 9 2 Changes Since Red Hat Enterprise Linux 5 9 The following features have been added since the release of OProfile included in Red Hat Enterprise Linux 5 9 OProfile now supports AMD family11h family12h family14h and AMD family15h processors Generation of XML output has been corrected Handling of the session dir command line option has been improved and a possible buffer 134 Changes in Version 2 0 overflow in the XML generator has been fixed A 10 Changes in Valgrind Red Hat Developer Toolset 2 0 is distributed with Valgrind 3 8 1 which provides a number of bug fixes over the version included in Red Hat Developer Toolset 1 1 Below is a comprehensive list of changes in this release A 10 1 Changes Since Red Hat Developer Toolset 1 1 The following features have been added since the release of Valgrind included in Red Hat Developer Toolset 1 1 The DWARF debug information for Valgrind is now distributed in a separate package devtoolset 2 valgrind debuginfo The S
70. d with OProfile type the following at a shell prompt as root scl enable devtoolset 2 tool option are distributed with Valgrind For example to use the ophelp command to list available events in the Red Hat Developer Toolset 2 x User Guide XML format type scl enable devtoolset 2 ophelp X Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset OProfile as default scl enable devtoolset 2 bash rraauA To verify the version of OProfile you are using at any point type the following at a shell prompt which opcontrol Red Hat Developer Toolset s opcontrol executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset OProfile opcontrol version 12 3 Additional Resources A detailed description of OProfile and its features is beyond the scope of this book For more information see the resources listed below Installed Documentation oprofile 1 The manual page named oprofile provides an overview of OProfile and available tools To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 2 man oprofile opannotate 1 oparchive 1
71. delete a breakpoint that is set at a certain line run the following command clear line number Similarly to delete a breakpoint that is set on a certain function run clear function name You can also delete all breakpoints at once To do so run the clear command with no additional arguments 51 Red Hat Developer Toolset 2 x User Guide clear Example 7 7 Deleting an Existing Breakpoint line 7 by running the following command gdb break 7 Breakpoint 2 at 0x4004e3 file fibonacci c line 7 To remove this breakpoint type gdb clear 7 Deleted breakpoint 2 7 6 Starting Execution To start execution of the program you are debugging run the following command run If the program accepts any command line arguments you can provide them as arguments to the run command run argument The execution stops when a first breakpoint if any is reached when an error occurs or when the program terminates Example 7 8 Executing the fibonacci Binary File execute the fibonacci binary file by running the following command gdb run Starting program home john fibonacci Breakpoint 1 main argc 1 argv 0x7fffffffe4d8 at fibonacci c 10 10 printf ld b 7 7 Displaying Current Values The gdb utility allows you to display the value of almost anything that is relevant to the program from a variable of any complexity to a valid expression or even a library function However the most common task is to disp
72. description of the InstructionAPI is stored in the InstructionAPI pdf file Red Hat Enterprise Linux 5 provides further details about SystemT ap See Also 82 and memory management problems such as the use of uninitialized memory improper allocation and freeing of memory and the use of improper arguments in system calls greatest amount of CPU time and why Part VI Getting Help Part VI Getting Help 83 Red Hat Developer Toolset 2 x User Guide Chapter 14 Accessing Red Hat Product Documentation a central source of information It is currently translated in 22 languages and for each product it provides different kinds of books from release and technical notes to installation user and reference guides in HTML PDF and EPUB formats Below is a brief list of documents that are directly or indirectly relevant to this book Red Hat Developer Toolset Red Hat Developer Toolset 2 0 explains the concept of Software Collections and documents the scl tool Red Hat Enterprise Linux provides detailed information about libraries and runtime support compiling and building debugging and profiling Red Hat Enterprise Linux 6 Installation Guide The nstallation Guide for Red Hat Enterprise Linux 6 explains how to obtain install and update the system Linux 6 documents relevant information regarding the deployment configuration and administration of Red Hat Enterprise Linux 6 Linux 5 documents relevant informat
73. devtoolset 2 dwz Note that in order to use this command you need to have access to the repository with these packages If your system is registered with Red Hat Subscription Management enable the rhel variant 20 Chapter 1 Red Hat Developer Toolset 1 6 Updating Red Hat Developer Toolset 1 6 1 Updating to a Minor Version When a new minor version of Red Hat Developer Toolset is available run the following command as root to update your Red Hat Enterprise Linux installation yum update This updates all packages on your Red Hat Enterprise Linux system including the Red Hat Developer Toolset versions the Eclipse development environment development debugging and performance monitoring tools the sc1 utility and other dependent packages Or important Use of Red Hat Developer Toolset requires the removal of any earlier pre release versions of this product Additionally it is not possible to update to Red Hat Developer Toolset 2 0 froma pre release version of Red Hat Developer Toolset including beta releases If you have previously installed any pre release version of Red Hat Developer Toolset uninstall it from your system as described in Section 1 7 Uninstalling Red Hat Developer T oolset section 1 gt Installing Red Hat Developer Toolset documented in 1 6 2 Updating to a Major Version When a new major version of Red Hat Developer Toolset is available you can install it in parallel with the previous v
74. directory If the o option is omitted the compiler creates a file named a out by default Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset 1d as default scl enable devtoolset 2 bash 39 Red Hat Developer Toolset 2 x User Guide To verify the version of 1d you are using at any point type the following at a shell prompt which ld Red Hat Developer Toolset s 1d executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset 1d 4 4 Using Other Binary Tools The binutils provide many binary tools other than a linker and assembler For a complete list of these To execute any of the tools that are part of binutils run the command as follows Scl enable devtoolset 2 tool option file name distributed with binutils For example to use the obj dump tool to inspect an object file type scl enable devtoolset 2 objdump option object file Note that you can execute any command using the sc l utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Too
75. ditional interaction with command line tools and as such it is a welcome alternative to developers who do not want to use the command line interface The traditional mostly command line based Linux tools suite such as gcc or gdb and Eclipse offer two distinct approaches to programming Red Hat Developer Toolset is distributed with Eclipse 4 3 0 which is based on the Eclipse Foundation s 2013 Eclipse 4 3 Kepler simultaneous release Note that if you intend to develop applications for Red Hat JBoss Middleware or require support for OpenShift Tools it is recommended 24 Table 2 1 Eclipse Components Included in Red Hat Developer Toolset Package devtoolset 2 eclipse cat devtoolset 2 eclipse emf devtoolset 2 eclipse gef devtoolset 2 eclipse rse devtoolset 2 eclipse jgit devtoolset 2 eclipse egit devtoolset 2 eclipse mylyn devtoolset 2 eclipse linuxtools devtoolset 2 eclipse changelog 1 Description The C C Development Tooling CDT which provides features and plug ins for development in C and C The Eclipse Modeling Framework EMF which allows you to build applications based on a structured data model The Graphical Editing Framework GEF which allows you to create a rich graphical editor from an existing application model The Remote System Explorer RSE framework which allows you to work with remote systems from Eclipse JGit a Java implementation of the Git revision control system EGit a team provid
76. documented in the user manual Fortran 2003 Support for unlimited polymorphic variables CLASS has been added Non constant character lengths are not yet supported TS 29113 Assumed types T YPE are now supported Experimental support for assumed rank arrays dimension has been added Note that at the moment the gfortran array descriptor is used which is different from the array descriptor defined in TS 29113 For more information see the header file of gfortran or use the Chasm language interoperability tools 97 Red Hat Developer Toolset 2 x User Guide A 2 1 6 x86 specific Improvements New Instructions GCC 4 8 has added support for the Intel FXSR XSAVE and XSAVEOPT instructions Corresponding intrinsics and built in functions can now be enabled by using the mfxsr mxsave and mxsaveopt command line options respectively In addition support for the RDSEED ADCX ADOX and PREFETCHW instructions has been added and can be enabled by using the mrdseed madx and mprfchw command line options New Built in Functions to Detect Run time CPU Type and ISA A new built in function builtin cpu is has been added to detect if the run time CPU is of a particular type This function accepts one string literal argument with the CPU name and returns a positive integer on a match and zero otherwise For example builtin cpu is westmere returns a positive integer if the run time CPU is an Intel Core i7 Westmere pro
77. e 3 2 2 Using the C Compiler 3 2 3 Running a C Program 3 3 GNU Fortran Compiler 3 3 1 Installing the Fortran Compiler 3 3 2 Using the Fortran Compiler 3 3 3 Running a Fortran Program 3 4 Additional Resources Installed Documentation Online Documentation See Also Chapter 4 Dinutils 5 x ror his epis UD Ee deed des iaia 4 1 Installing binutils 4 2 Using the GNU Assembler 4 3 Using the GNU Linker 4 4 Using Other Binary Tools 4 5 Additional Resources Installed Documentation Online Documentation See Also Chapter 5 elfutils 0 5 1 Installing elfutils 5 2 Using elfutils 5 3 Additional Resources See Also Chaptero dWz oU E RE SEE RL e ENDE NE ES 6 1 Installing dwz 6 2 Using dwz 6 3 Additional Resources Installed Documentation See Also Part IV Debugging Tools 0 00 ccc see Chapter 7 GNU Debugger GDB aaa 7 1 Installing the GNU Debugger 7 2 Preparing a Program for Debugging Compiling Programs with Debugging Information Installing Debugging Information for Existing Packages 7 3 Running the GNU Debugger 7 4 Listing Source Code 7 5 Setting Breakpoints Setting a New Breakpoint Listing Breakpoints Deleting Existing Breakpoints 7 6 Starting Execution 7 7 Displaying Current Values 7 8 Continuing Execution 7 9 Additional Resources Online Documentation See Also Chapter S strace chin detent be bet eR aa wae ATA D RI 8 1 Installing strace 8
78. e performance Overall the development experience should be better than the default optimization level 00 Caret Diagnostic Messages The diagnostic messages of GCC which display a line of source code now also show a caret that indicates the column where the problem was detected For example fred cc 4 15 fatal error foo No such file or directory include foo compilation terminated New fira hoist pressure Option A new command line option fira hoist pressure has been added This option uses the register allocator to help decide when it is worthwhile to move expressions out of loops It can reduce the size of 94 Changes in Version 2 0 the compiler code but it slows down the compiler This option is enabled by default at Os New fopt info Option A new command line option fopt info has been added This option controls printing information about the effects of particular optimization passes and takes the following form fopt info info file name The info part of the option controls what is printed Replace it with optimized to print information when optimization takes place missed to print information when optimization does not take place note to print more verbose information or optall to print everything Replace file name with the name of the file in which you want the information to be written If you omit this part of the option GCC writes the information to the standard error output stream
79. e 8 1 Redirecting Output to a File allows you to specify how many members of this sequence to list To run the strace utility on this file and redirect the trace output to fibonacci log type scl enable devtoolset 2 strace o fibonacci log fibonacci 20 1123 5 8 13 21 34 55 89 144 233 377 610 987 1597 2584 4181 6765 This creates a new plain text file called fibonacci log in the current working directory 8 2 2 Tracing Selected System Calls To trace only a selected set of system calls run the strace utility with the e command line option scl enable devtoolset 2 strace e expression program argument Replace expression with a comma separated list of system calls to trace or any of the keywords listed see the strace 1 manual page Table 8 1 Commonly Used Values of the e Option Value Description file System calls that accept a file name as an argument process System calls that are related to process management network System calls that are related to networking signal System calls that are related to signal management ipc System calls that are related to inter process communication IPC desc System calls that are related to file descriptors Red Hat Developer Toolset 2 x User Guide Example 8 2 Tracing Selected System Calls executable file and trace only the mmap and munmap system calls type scl enable devtoolset 2 strace e mmap munmap employee mmap NULL 4096 PROT READ PROT WRITE MAP_
80. e is not present Consequently the results are less likely to match the true result for the machine and should not be considered authoritative but provide a general idea about a program s locality A new command line option pages as heap has been added to Massif When this option is enabled Massif tracks memory allocations at the level of memory pages as mapped by mmap brk and similar functions instead of tracking allocations at the level of heap blocks as allocated with malloc new or new Each mapped page is treated as its own block Interpreting the page level output is harder than the heap level output but allows you to account for every byte of memory used by a program By default the pages as heap option is disabled New command line options free is write and trace alloc have been added to DRD The free is write option allows you to detect reading from already freed memory the trace alloc can be used to trace of all memory allocations and deallocations A number of new allocations have been added to DRD As well you can now annotate custom barrier implementations and benign races on static variables DRD s happens before and happens after annotations have been enhanced and can be used to annotate for example a smart pointer implementation Helgrind s annotation set has been significantly improved to provide a general set of annotations to 135 Red Hat Developer Toolset 2 x User Guide describe locks semaph
81. e to compute its value and the value method computes the symbol s value The gdb Value object now has a new method referenced value This method can be used to dereference a pointer as well as C reference values The gdb Symtab object now has two new methods global blockand static block These methods return the global and static blocks as gdb Block objects of the underlying symbol table respectively A new method gdb find pc line returns the gdb Symtab and line object associated with a PC value The gdb Symtab and line object now has an additional attribute last This attribute holds the end of the address range occupied by the code for the current source line Compatibility Changes 129 Red Hat Developer Toolset 2 x User Guide A new command info auto load has been added and can be used to display the status of various automatically loaded files The info auto load gdb scripts command lists automatically loaded canned sequences of commands info auto load python scripts displays the status of automatically loaded Python scripts info auto load local gdbinit displays whether a local gdbinit file in the current working directory is loaded and info auto load libthread db displays whether the inferior specific thread debugging shared library is loaded New commands set auto load and show auto load have been added and can be used to control automatic loading of files The set auto load gdb scripts and show auto load gdb scripts comm
82. e to the normal kinds of interference by concurrent threads that use the same resources such as the CPU Transactional memory support in GCC and libitm is still experimental and both the ABI and API could change in the future if this is required due to the evolution of the specification of the language constructs or due to implementation requirements Note that when executing applications built with the fgnu tm command line option it is currently a prerequisite to also have the appropriate version of the libitm so 1 shared library installed A 2 2 1 4 Architecture specific Options Red Hat Developer Toolset 2 0 is only available for Red Hat Enterprise Linux 5 and 6 both for the 32 bit and 64 bit Intel and AMD architectures Consequently the options described below are only relevant to these architectures Optimization for several processors is now available through the command line options described in 103 Table A 1 Processor Optimization Options Option Description march core2 and mtune core2 Optimization for Intel Core 2 processors march corei7 and mtune corei7 Optimization for Intel Core i3 i5 and i7 processors march corei7 avx and mtune corei7 Optimization for Intel Core i3 i5 and i7 avx processors with AVX march core avx i Optimization for the Intel processor code named Ivy Bridge with RDRND FSGSBASE and F16C march core avx2 Optimization for a next generation processor from Intel with AVX2 FMA BMI
83. ecord full insn number max The set record memory query and show record memory query commands have been renamed to set record full memory query and show record full memory query The set record stop at limit and show record stop at limit commands have been renamed to set record full stop at limit and show record full stop at limit A new record target record btrace has been added This target uses hardware support to record the control flow of a process and can be enabled by using the record btrace command This record target does not support replaying the execution POP important NN The record btrace target is only available on Intel Atom processors and requires the Linux kernel in version 2 6 32 or later 122 Changes in Version 2 0 New record instruction history and record function call history commands have been added These commands allow you to view information about an execution log without having to replay it The record instruction history command displays the execution history at instruction granularity and the record function call history displays the execution history at function granularity The commands are only supported by the record btrace command A new command line option nh has been added This option allows you to disable automatic loading of the gdbinit file without disabling other initialization files The epoch command line option has been removed This option was used by GDB mode in Epoch a deprecated c
84. ed at opt rh devtoolset 2 root usr share doc devtoolset 2 systemtap client 2 1 index html Online Documentation 68 Chapter 10 SystemTap documentation on SystemT ap as well as numerous examples of SystemT ap scripts See Also over the Red Hat Enterprise Linux system version of SystemT ap and the version distributed in the previous release of Red Hat Developer Toolset and memory management problems such as the use of uninitialized memory improper allocation and freeing of memory and the use of improper arguments in system calls executable 69 Red Hat Developer Toolset 2 x User Guide Chapter 11 Valgrind Valgrind is an instrumentation framework that ships with a number of tools to profile applications It can be used to detect various memory errors and memory management problems such as the use of uninitialized memory or improper allocation and freeing of memory or to identify the use of improper arguments in system calls For a complete list of profiling tools that are distributed with the Red Hat Valgrind profiles an application by rewriting it and instrumenting the rewritten binary This allows you to profile your application without the need to recompile it but it also makes Valgrind significantly slower than other profilers especially when performing extremely detailed runs It is therefore not suited to debugging time specific issues or kernel space debugging Red Hat Developer Toolset is distributed with
85. ed on your system If not alternative but equivalent typefaces are displayed Note Red Hat Enterprise Linux 5 and later include the Liberation Fonts set by default 1 1 Typographic Conventions Four typographic conventions are used to call attention to specific words and phrases These conventions and the circumstances they apply to are as follows Mono spaced Bold Used to highlight system input including shell commands file names and paths Also used to highlight keys and key combinations For example To see the contents of the file my_next_bestselling_novel in your current working directory enter the cat my_next_bestselling_novel command at the shell prompt and press Enter to execute the command The above includes a file name a shell command and a key all presented in mono spaced bold and all distinguishable thanks to context Key combinations can be distinguished from an individual key by the plus sign that connects each part of a key combination For example Press Enter to execute the command Press Ctrl Alt F2 to switch to a virtual terminal The first example highlights a particular key to press The second example highlights a key combination a set of three keys pressed simultaneously If source code is discussed class names methods functions variable names and returned values mentioned within a paragraph will be presented as above in mono spaced bold For example File related classes include filesystem for
86. ely affect scripts that rely on undocumented behavior of the old expression evaluation Changes Since Red Hat Enterprise Linux 5 9 The following compatibility changes have been made since the release of binutils included in Red Hat Enterprise Linux 5 9 The add needed command line option has been renamed to copy dt needed entries in order to avoid confusion with the as needed option For GNU Linux systems the linker no longer processes any relocations made against symbols of the STT GNU IFUNC type Instead it emits them into the resulting binary for processing by the loader CO The implementation of this feature depends on capabilities only found in newer versions of the glibc library Consequently this feature is currently available in Red Hat Developer Toolset for Red Hat Enterprise Linux 6 The as needed command line option has been adapted to link in a dynamic library in the following two cases 1 if the dynamic library satisfies undefined symbols in regular objects and 2 if the dynamic library satisfies undefined symbols in other dynamic libraries unless the library 117 Red Hat Developer Toolset 2 x User Guide is already found in a DT_NEEDED entry of one of the libraries that are already linked The 1 file name command line option now searches the library path for a file name called file name without adding the a or so file extension A 3 2 GNU Assembler A 3 2 1 New Features Changes Since Red Hat
87. eplace variant with the Red Hat Enterprise Linux system variant server or workstation and version with the Red Hat Enterprise Linux system version 5 or 6 4 Enable the appropriate repository On Red Hat Enterprise Linux 6 you can do so by running the following command as root yum config manager enable repository On Red Hat Enterprise Linux 5 which does not support the yum config manager tool edit the etc yum repos d redhat repo file locate the relevant repository section and set the value of the enabled option to 1 enabled 1 Once the subscription is attached to the system you can install Red Hat Developer Toolset as your system using Red Hat Subscription Management and associate it with subscriptions see the Red Hat Subscription Management Guide 1 5 Installing Red Hat Developer Toolset 18 Chapter 1 Red Hat Developer Toolset Red Hat Developer Toolset is distributed as a collection of RPM packages that can be installed updated uninstalled and inspected by using the standard package management tools that are included in Red Hat Enterprise Linux Note that a valid subscription is required in order to install Red Hat Developer Toolset on your system For detailed instructions on how to associate your system with an Before installing Red Hat Developer Toolset on a system that is already running the previous version of the product make sure that the devtoolset 1 1 gcc debuginfo is not installed To uninstall t
88. er Guide Changes in Version 2 0 The sections below document features and compatibility changes introduced in Red Hat Developer Toolset 2 0 A 1 Changes in Eclipse Red Hat Developer Toolset 2 0 is distributed with Eclipse 4 3 and a wide selection of plug ins from the Eclipse Foundation s 2013 Eclipse 4 3 Kepler release and provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version Below is a comprehensive list of new features compatibility changes in this release For details on how to use these new features see the built in Eclipse documentation A 1 1 Changes Since Red Hat Enterprise Linux 6 4 The following features have been added since the release of the Eclipse Platform and native plug ins included in Red Hat Enterprise Linux 6 4 The Eclipse Platform has been updated to from version 3 6 to 4 3 This new major release features a more flexible user interface based on Eclipse Modeling Framework EMF CSS based themes dependency injection and more The Eclipse C C Development Toolkit CDT has been updated from version 7 0 to 8 2 This new major release includes a greatly enhanced indexer both in terms of capabilities and speed improved GNU Debugger integration support for GNU Debugger s pretty printing multi process debugging project less debugging enhanced refactoring code checking capabilities an improved and more polished user interface Mylyn a set
89. er for Eclipse that provides features and plug ins for interaction with Git repositories Mylyn a task management system for Eclipse A meta package for Linux specific Eclipse plug ins The ChangeLog plug ins which allows you to create and maintain changelog files The GCov plug in which integrates the GCov test coverage program with Eclipse The Gprof plug in which integrates the Gprof performance analysis utility with Eclipse The Man Page plug in which allows you to view manual pages in Eclipse The OProfile plug in which integrates OProfile with Eclipse The Perf plug in which integrates the perf tool with Eclipse The Eclipse Spec File Editor which allows you to maintain RPM spec files The RPM Stubby plug in which allows you to generate RPM spec files The SystemT ap plug in which integrates SystemT ap with Eclipse The Valgrind plug in which integrates Valgrind with Eclipse a This package is installed as a dependency of devtoolset 2 eclipse linuxtools 2 1 Installing Eclipse In Red Hat Developer Toolset the Eclipse development environment is provided as a collection of RPM Red Hat Developer Toolset 2 x User Guide rraaum The Red Hat Developer Toolset version of Eclipse is only available for Red Hat Enterprise Linux 6 on 32 bit and 64 bit Intel and AMD architectures This version fully supports C C and Java development but does not provide support for the Fortran prog
90. er to submit service requests If the severity is level 1 or 2 then follow up your service request with a phone call Contact information If you have a premium subscription then after hours support is available for Severity 1 and 2 cases Turn around rates for both premium subscriptions and standard subscription can be found at ion sla html 16 2 Escalating an Issue If you feel as though an issue is not being handled correctly or adequately you can escalate it There are two types of escalation Technical escalation If an issue is not being resolved appropriately or if you need a more senior resource to attend to it Management escalation If the issue has become more severe or you believe it requires a higher priority More information on escalation including contacts is available at 90 Chapter 16 Contacting Global Support Services 16 3 Re opening a Service Request If more relevant information regarding a closed service request such as the problem reoccurring you can re open it via the Red Hat Customer Portal at In order to re open a service request you need the original service request number 16 4 Additional Resources For more information see the resources listed below Online Documentation Red Hat subscription and offers the Red Hat Welcome Kit and Quick Guide to Red Hat Support for download frequent questions about public Red Hat mailing lists 91 Red Hat Developer Toolset 2 x Us
91. eration number 5 Iteration number Iteration number Iteration number Iteration number PNW SA When the exercise program terminates the count program displays the number of times the print_iteration function was executed Function executed 5 times 13 3 Additional Resources A detailed description of Dyninst and its features is beyond the scope of this book For more information see the resources listed below Installed Documentation The devtoolset 2 dyninst doc package installs the following documents in the opt rh devtoolset 2 root usr share doc devtoolset 2 dyninst doc 8 0 directory Dyninst Programmer s Guide A detailed description of the Dyninst API is stored in the DyninstAPI pdf file DynC API Programmer s Guide An introduction to DynC API is stored in the dynC_API pdf file ParseAPI Programmer s Guide An introduction to the ParseAPI is stored in the ParseAPL pdf file PatchAPI Programmer s Guide An introduction to PatchAPI is stored in the PatchAPI pdf file ProcControlAPI Programmer s Guide A detailed description of ProcControlAPI is stored in the ProcControlAPI pdf file StackwalkerAPI Programmer s Guide A detailed description of StackwalkerAPI is stored in the stackwalker pdf file SymtabAPI Programmer s Guide An introduction to SymtabAPI is stored in the SymtabAPI pdf file 81 Red Hat Developer Toolset 2 x User Guide InstructionAPI Reference Manual A detailed
92. ercise exercise C g CXXFLAGS exercise C o exercise PHONY clean clean rm rf o count exercise To compile the two programs on the command line using the g compiler from Red Hat Developer Toolset run the make utility as follows scl enable devtoolset 2 make g g I opt rh devtoolset 2 root usr include dyninst count C c g g I opt rh devtoolset 2 root usr include dyninst count o L opt rh devtoolset 2 root usr lib64 dyninst ldyninstAPI o count g g I opt rh devtoolset 2 root usr include dyninst exercise C o exercise This creates new binary files called exercise and count in the current working directory In one shell session execute the exercise binary file as follows and wait for it to prompt you to enter the starting number 80 Chapter 13 Dyninst exercise Enter the starting number Do not enter this number Instead start another shell session and type the following at its prompt to set the DYNINSTAPI_RT_LIB environment variable and execute the count binary file export DYNINSTAPI RT LIB opt rh devtoolset 2 root usr lib64 dyninst libdyninstAPI RT so 8 0 count pidof exercise print iteration Finding function print iteration OK Instrumenting function print iteration OK Waiting for process 8607 to exit Now switch back to the first shell session and enter the starting number as requested by the exercise program For example Enter the starting number 5 It
93. ersion of the product For detailed instructions on how to install Red Hat Developer 1 7 Uninstalling Red Hat Developer Toolset To uninstall Red Hat Developer Toolset packages from your system type the following at a shell prompt as root yum remove devtoolset 2 This removes the GNU Compiler Collection GNU Debugger binutils and other packages that are part of Red Hat Developer Toolset from the system To uninstall the sc1 utility as well type as root yum remove scl utils Note that uninstallation of the tools provided by Red Hat Developer Toolset does not affect the Red Hat Enterprise Linux system versions of these tools 21 Red Hat Developer Toolset 2 x User Guide 1 8 Additional Resources For more information about Red Hat Developer Toolset and Red Hat Enterprise Linux see the resources listed below Online Documentation provides more information on the Eclipse IDE libraries and runtime support compiling and building debugging and profiling on this system Linux 6 documents relevant information regarding the deployment configuration and administration of Red Hat Enterprise Linux 6 Linux 5 documents relevant information regarding the deployment configuration and administration of Red Hat Enterprise Linux 5 See Also 22 over the Red Hat Enterprise Linux system versions of the GNU Compiler Collection GNU Debugger and binutils as well as information about the language ABI and debugging compat
94. esources than Valgrind but also causes its samples to be less precise Unlike Valgrind which only collects data for a single process and its children in user space OProfile is well suited to collect system wide data on both user space and kernel space processes and requires root privileges to run Red Hat Developer Toolset is distributed with OProfile 0 9 8 This version is more recent than the version included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements Table 12 1 Tools Distributed with OProfile for Red Hat Developer Toolset Name Description oprofiled The OProfile daemon that collects profiling data opcontrol Starts stops and configures the OProfile daemon opannotate Generates an annotated source file or assembly listing form the profiling data oparchive Generates a directory containing executable debug and sample files opgprof Generates a summary of a profiling session in a format compatible with gprof ophelp Displays a list of available events opimport Converts a sample database file from a foreign binary format to the native format opjitconv Converts a just in time JIT dump file to the Executable and Linkable Format ELF opreport Generates image and symbol summaries of a profiling session 12 1 Installing OProfile In Red Hat Developer Toolset OProfile is provided by the devtoolset 2 oprofile package and is 12 2 Using OProfile To run any of the tools that are distribute
95. et toolchain from the system type the following at a shell prompt as root yum remove devtoolset 2 gcc devtoolset 2 binutils To configure Eclipse to explicitly use the Red Hat Enterprise Linux system versions of the tools for the current project complete the following steps 1 In the C C perspective choose Project Properties from the main menu bar to open the project properties 2 In the menu on the left hand side of the dialog box click C C Build Settings 3 Select the Tool Settings tab 4 If you are working on a C project a select GCC C Compiler or Cross GCC Compiler and change the value of the Command field to usr bin gcc b select GCC C Linker or Cross GCC Linker and change the value of the Command field to usr bin gcc c select GCC Assembler or Cross GCC Assembler and change the value of the Command field to usr bin as If you are working on a C project a select GCC C Compiler or Cross G Compiler and change the value of the Command field to usr bin g b select GCC C Compiler or Cross GCC Compiler and change the value of the Command field to 27 Red Hat Developer Toolset 2 x User Guide usr bin gcc c select GCC C Linker or Cross G Linker and change the value of the Command field to usr bin g d select GCC Assembler or Cross GCC Assembler and change the value of the Command field to usr bin as 5 Click the OK button to save the configuration
96. execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset SystemT ap as default scl enable devtoolset 2 bash rraum To verify the version of SystemT ap you are using at any point type the following at a shell prompt which stap Red Hat Developer Toolset s stap executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset SystemT ap stap V 10 3 Additional Resources A detailed description of SystemT ap and its features is beyond the scope of this book For more information see the resources listed below Installed Documentation stap 1 The manual page for the stap command provides detailed information on its usage as well as references to other related manual pages To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 2 man stap staprun 8 The manual page for the staprun command provides detailed information on its usage To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 2 man staprun SystemTap Tapset Reference Manual HTML documentation on the most common tapset definitions is locat
97. file systems file for files and dir for directories Each class has its own associated set of permissions Proportional Bold This denotes words or phrases encountered on a system including application names dialog box text labeled buttons check box and radio button labels menu titles and sub menu titles For example Choose System Preferences Mouse from the main menu bar to launch Mouse Preferences In the Buttons tab select the Lef t handed mouse check box and click Close to switch the primary mouse button from the left to the right making the mouse suitable for use in the left hand To insert a special character into a gedit file choose Applications Accessories Preface Character Map from the main menu bar Next choose Search Find from the Character Map menu bar type the name of the character in the Search field and click Next The character you sought will be highlighted in the Character Table Double click this highlighted character to place it in the Text to copy field and then click the Copy button Now switch back to your document and choose Edit Paste from the gedit menu bar The above text includes application names system wide menu names and items application specific menu names and buttons and text found within a GUI interface all presented in proportional bold and all distinguishable by context Mono spaced Bold Italic or Proportional Bold Italic Whether mono spaced bold or proportional bo
98. form scl enable devtoolset 2 gcc g o output_file input_file Similarly to compile a C program with debugging information run scl enable devtoolset 2 g g o output file input file 47 Red Hat Developer Toolset 2 x User Guide Example 7 1 Compiling a C Program With Debugging Information Consider a source file named fibonacci c that has the following contents include lt stdio h gt include lt limits h gt int main int argc char argv unsigned long int a 0 unsigned long int b 1 unsigned long int sum while b LONG MAX printf ld b sum a b a S bj b sum return 0 J To compile this program on the command line using GCC from Red Hat Developer Toolset with debugging information for the GNU Debugger type scl enable devtoolset 2 gcc g o fibonacci fibonacci c This creates a new binary file called fibonacci in the current working directory Installing Debugging Information for Existing Packages To install debugging information for a package that is already installed on the system type the following at a shell prompt as root debuginfo install package_name Note that the yum utils package must be installed for the debuginfo install utility to be available on your system Example 7 2 Installing Debugging Information for the glibc Package To install debugging information for the glibc package type debuginfo install glibc Loaded plugins produ
99. h a non constant length type parameter are now supported Support has been added for procedure pointer function results and procedure pointer components including PASS Support has been added for allocatable scalars experimental DEFERRED type bound procedures and the ERRMSG argument of the ALLOCATE and DEALLOCATE statements The ALLOCATE statement now supports type specs and the SOURCE argument Rounding ROUND RZ for output is now supported The INT FAST 8 16 32 64 128 T format for ISO C BINDING intrinsic module type parameters is now supported OPERATOR and ASSIGNMENT are now allowed as GENERIC type bound procedures i e as type bound operators A 2 2 2 4 4 Fortran 2003 Compatibility Extensible derived types with type bound procedure or procedure pointer with PASS attribute now have to use CLASS in line with the Fortran 2003 standard the workaround to use T YPE is no longer supported 112 Changes in Version 2 0 A 2 2 2 4 5 Fortran 2008 Features A new command line option std f2008ts has been added This option enables support for programs that conform to the Fortran 2008 standard and the draft Technical Specification T S The DO CONCURRENT construct is now supported This construct can be used to specify that individual loop iterations do not have any interdependencies Full single image support except for polymorphic coarrays has been added and can be enabled by using the fcoarray single comm
100. his package from the system type the following at a shell prompt as root yum remove devtoolset 1 1 gcc debuginfo After installing Red Hat Developer Toolset it is recommended to apply all available Red Hat Enterprise Linux errata updates to enable all Red Hat Developer Toolset features and apply fixes that may otherwise impact the tools or built code 1 5 1 Installing All Available Components To install all components that are included in this product install the devtoolset 2 package by typing the following at a shell prompt as root yum install devtoolset 2 This installs the Eclipse development environment all development debugging and performance 1 5 2 Installing Individual Package Groups To make it easier to install only certain components such as the integrated development environment or the software development toolchain Red Hat Developer Toolset is distributed with a number of meta Table 1 3 Red Hat Developer Toolset Meta Packages Package Name Description Installed Components devtoolset 2 ide Integrated Development Eclipse Environment devtoolset 2 perftools Performance monitoring tools SystemT ap Valgrind OProfile Dyninst devtoolset 2 toolchain Development and debugging tools GCC GDB binutils elfutils dwz memstomp strace 19 Red Hat Developer Toolset 2 x User Guide To install any of these meta packages type the following at a shell prompt as root yum install package_name Replace package_
101. ibility Part Il Integrated Development Environments Part Il Integrated Development Environments 23 Red Hat Developer Toolset 2 x User Guide Chapter 2 Eclipse Eclipse is a powerful development environment that provides tools for each phase of the development process It integrates a variety of disparate tools into a unified environment to create a rich development experience provides a fully configurable user interface and features a pluggable architecture that allows for extension in a variety of ways For instance the Valgrind plug in allows programmers to perform memory profiling otherwise performed on the command line through the Eclipse user interface Ale Edit Source Refactor Navigate Search Project Run Window Help m o 9 a i CJ E 4 vj u Q C Resource Project Explorer z p hello c 21 v Name Hello c D X v 5 Hello World in C include lt stdio h gt gt jg Includes include lt stdlib h gt v Bsr int main void t j 7 a hello c puts Hello World l prints IHello World u stdio h return EXIT SUCCESS u stdlib h e main void nt gt p Debug peer amp Outline 3 T a wwe stdio h u stdib h Tasks E Console 22 rj e main void t mcn SO No consoles to display at this tme Writable Srnart Insert 17 2 Figure 2 1 Sample Eclipse Session Eclipse provides a graphical development environment alternative to tra
102. ies in the United States and or other countries MySQL is a registered trademark of MySQL AB in the United States the European Union and other countries Node js is an official trademark of Joyent Red Hat Software Collections is not formally related to or endorsed by the official Joyent Node js open source or commercial project The OpenStack Word Mark and OpenStack Logo are either registered trademarks service marks or trademarks service marks of the OpenStack Foundation in the United States and other countries and are used with the OpenStack Foundation s permission We are not affiliated with endorsed or sponsored by the OpenStack Foundation or the OpenStack community All other trademarks are the property of their respective owners Keywords Abstract Red Hat Developer Toolset is a Red Hat offering for developers on the Red Hat Enterprise Linux platform The Red Hat Developer Toolset User Guide provides an overview of this product explains how to invoke and use the Developer Toolset versions of the tools and links to resources with more in depth information Table of Contents con AEA RE EAE E A OA EAA Me I AA AAE AA A ESAE A allinea 8 1 Document Conventions 1 1 Typographic Conventions 1 2 Pull quote Conventions 1 3 Notes and Warnings 2 Getting Help and Giving Feedback 2 1 Do You Need Help 2 2 We Need Feedback Part Introd ctiOR o uo tentes i E nA EB gelu Evi IU bu ER CENTER RR E E Chapter 1 Red Hat Developer T
103. ince the release of elfutils included in Red Hat Developer Toolset 1 1 In the 1ibdw library the DW LANG Objc constant has been correctly renamed to DW LANG 0bjC Note that any existing source code that uses the old name needs to be updated accordingly The libdw library now supports new constants DW ATE UTF and DW OP GNU parameter ref In addition it also defines a family of constants to support the debug macro section namely DW MACRO GNU define DW MACRO GNU undef DW MACRO GNU start file DW MACRO GNU end file DW MACRO GNU define indirect DW MACRO GNU undef indirect and DW MACRO GNU transparent include When working with the 1ibelf library both e1f32 xlatetomd and elf64 xlatetomd now work for cross endian ELF note data The elf getshdr function provided by the Libelf library has been corrected to work consistently on non mmapped ELF files after making the e1f cntl ELF C FDREAD function call The libelf library now supports ar archives with a 64 bit symbol table 120 Changes in Version 2 0 The eu readelf command is now able to display the contents of the debug macro section The eu readelf command now correctly recognizes the DW OP GNU parameter ref DWARF GNU extension opcode in location expressions A 4 2 Changes Since Red Hat Enterprise Linux 6 4 The following features have been added since the release of elfutils included in Red Hat Enterprise Linux 6 4 The libdw library now handles compressed debuginf
104. included in Red Hat Developer Toolset type scl enable devtoolset 2 man memstomp See Also and memory management problems such as the use of uninitialized memory improper allocation and freeing of memory and the use of improper arguments in system calls 65 66 Red Hat Developer Toolset 2 x User Guide Part V Performance Monitoring Tools Chapter 10 SystemTap Chapter 10 SystemTap SystemTap is a tracing and probing tool that allows users to monitor the activities of the entire system without needing to instrument recompile install and reboot It is programmable with a custom scripting language which gives it expressiveness to trace filter and analyze and reach to look into the running kernel and applications SystemT ap can monitor various types of events such as function calls within the kernel or applications timers tracepoints performance counters and so on Some included example scripts produce output similar to netstat ps top and iostat others include pretty printed function callgraph traces or tools for working around security bugs Red Hat Developer Toolset is distributed with SystemTap 2 1 Table 10 1 Tools Distributed with SystemTap for Red Hat Developer Toolset Name Description stap Translates probing instructions into C code builds a kernel module and loads it into a running Linux kernel staprun Loads unloads attaches to and detaches from kernel modules built with the stap utility
105. information It is suggested to use the gdwarf 2 gstrict dwarf options with those tools rrauuA U Use of Link time Optimization with debug generation is not yet supported in gcc 4 7 and 4 8 and so use of the f1to and the g options together is unsupported in Red Hat Developer Toolset A 2 2 5 Other Compatibility GCC is now more strict when parsing command line options and both gcc and g report an error when invalid command line options are used In particular when only linking and not compiling code earlier versions of GCC ignored all options starting with For example options accepted by the linker such as as needed and export dynamic are not accepted by gcc and g anymore and should now be directed to the linker using W1 as needed or W1 export dynamic if that is intended support for the older intermodule optimization framework has been removed and the combine command line option is not accepted anymore A 3 Changes in binutils Red Hat Developer Toolset 2 0 is distributed with binutils 2 23 52 which provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version and the version 115 Red Hat Developer Toolset 2 x User Guide included in Red Hat Developer Toolset 1 1 Below is a comprehensive list of new features in this release The GNU assembler as GNU linker 1d and other binary tools that are part of binutils are now released under the GNU Gener
106. inlined memcpy calls and similar A 2 2 1 5 Link time Optimization Link time optimization LTO is a compilation technique in which GCC generates an internal representation of each compiled input file in addition to the native code and writes both to the output object file Subsequently when several object files are linked together GCC uses the internal representations of the compiled code to optimize inter procedurally across all the compilation units This can potentially improve the performance of the generated code for example functions defined in one file can potentially be inlined when called in another file To enable LTO the f1to option needs to be specified at both compile time and link time For further details including interoperability with linkers and parallel execution of LTO refer to the documentation for LTO will only apply to code generated by the same version of GCC K P _ _z Use of Link time Optimization with debug generation is not yet supported in gcc 4 7 and 4 8 and so use of the flto and the g options together is unsupported in Red Hat Developer Toolset A 2 2 1 6 Miscellaneous Ofast is now supported as a general optimization level It operates similar to 03 adds options that can yield better optimized code but in turn might invalidate standards compliance for example f fast math is enabled by Ofast GCC can now inform users about cases in which code generation might be improved by addi
107. ion regarding the deployment configuration and administration of Red Hat Enterprise Linux 5 84 Chapter 15 Accessing the Customer Portal Chapter 15 Accessing the Customer Portal The Customer Portal is available to all Red Hat subscribers and can be accessed at of most interest to developers are the Plan Deploy and Connect menus These include links to all the resources needed during each stage of the development 15 1 The Plan Menu Webinars Success Stories CONNECT Product Documentation Reference Architectures Evaluations amp Demos Certified Hardware Figure 15 1 The Plan Menu In the Plan menu are resources needed to plan a development project These menu items provide proven resources to implement the best solution the first time This includes Webinars The Webinars page contains information on upcoming Red Hat and open source events around the world Here you can register for upcoming webinars or watch archived ones on demand Success Stories Read the success stories of other Red Hat customers to learn how leading organizations are finding unbeatable value performance security and reliability with Red Hat solutions Product Documentation This provides a list of links to the various Red Hat documents including books for Red Hat Enterprise Linux Identity Management and Infrastructure Red Hat Enterprise Storage JBoss Enterprise Middleware and System Management Reference Architectures
108. lay the value of a variable To display the current value of a certain variable run the following command 52 Chapter 7 GNU Debugger GDB print variable_name Example 7 9 Displaying the Current Values of Variables and the execution of the fibonacci binary stopped after reaching the breakpoint at line 10 you can display the current values of variables a and b as follows gdb print a 1 0 gdb print b 2 1 7 8 Continuing Execution To resume the execution of the program you are debugging after it reached a breakpoint run the following command continue The execution stops again when another breakpoint is reached To skip a certain number of breakpoints typically when you are debugging a loop you can run the continue command in the following form continue number The gdb utility also allows you to stop the execution after executing a single line of code To do so run step Finally you can execute a certain number of lines by using the step command in the following form step number 53 Red Hat Developer Toolset 2 x User Guide Example 7 10 Continuing the Execution of the fibonacci Binary File and the execution of the fibonacci binary stopped after reaching the breakpoint at line 10 you can resume the execution by running the following command gdb continue Continuing Breakpoint 1 main argc 1 argv 0x7fffffffe4d8 at fibonacci c 10 10 printf ld b The execution stops the next
109. ld the addition of italics indicates replaceable or variable text Italics denotes text you do not input literally or displayed text that changes depending on circumstance For example To connect to a remote machine using ssh type ssh username domain name at a shell prompt If the remote machine is example com and your username on that machine is john type ssh john example com The mount o remount file system command remounts the named file system For example to remount the home file system the command is mount o remount home To see the version of a currently installed package use the rpm q package command It will return a result as follows package version release Note the words in bold italics above username domain name file system package version and release Each word is a placeholder either for text you enter when issuing a command or for text displayed by the system Aside from standard usage for presenting the title of a work italics denotes the first use of a new and important term For example Publican is a DocBook publishing system 1 2 Pull quote Conventions Terminal output and source code listings are set off visually from the surrounding text Output sent to a terminal is set in mono spaced roman and presented thus books Desktop documentation drafts mss photos stuff svn books tests Desktop1 downloads images notes scripts svgs Source code listings are also set in mono spaced roman but add synta
110. le Red Hat Developer Toolset by using the Red Hat Subscription Management or by using RHN Classic For detailed instructions on how to enable Red Hat Developer Toolset using RHN Classic or Red Hat Subscription Management see the respective section below For information on how to register your system with one of these subscription management services see the Red Hat Subscription Management Guide If you are running a version of Red Hat Enterprise Linux prior to 5 9 or 6 4 you will be unable to download Red Hat Developer Toolset through Red Hat Subscription Management To obtain Red Hat Developer Toolset you will need to either update to Red Hat Enterprise Linux 5 9 or 6 4 or register your system with RHN Classic For more information see 16 Chapter 1 Red Hat Developer Toolset Table 1 2 Subscriptions That Provide Red Hat Developer Toolset SKU Subscription Name RH2282403 Red Hat Enterprise Linux Developer Support Professional RH2264664 Red Hat Enterprise Linux Developer Support Enterprise RH22624 74 Red Hat Enterprise Linux Developer Suite RH3482727 Red Hat Enterprise Linux Developer Workstation Professional RH34 13336 Red Hat Enterprise Linux Developer Workstation Enterprise RH3414706 30 day Self Supported Red Hat Enterprise Linux Developer Workstation Evaluation RH3474212 60 day Supported Red Hat Enterprise Linux Developer Workstation Evaluation RH3437268 90 day Supported Red Hat Enterprise Linux Developer Workstation Eva
111. led the module and all files which directly use such symbols have to be recompiled as well This change only affects the following kind of module symbols Procedure pointers Note that C interoperable function pointers type c_funptr are not affected nor are procedure pointer components Deferred length character strings A 2 1 5 3 Other Changes BACKTRACE Intrinsic A new intrinsic subroutine BACKT RACE has been added This subroutine shows a backtrace at an arbitrary place in user code program execution continues normally afterwards Floating Point Numbers with q as Exponential Reading floating point numbers that use q for the exponential such as 4 0q0 is now supported as a vendor extension for better compatibility with old data files It is strongly recommended to use the equivalent but standard conforming e such as 4 0e0 for I O For Fortran source code consider replacing the q in floating point literals by a kind parameter such as 4 0e0 qp with a suitable qp Note that in Fortran source code replacing q with a simple e is not equivalent GFORTRAN TMPDIR Environment Variable The GFORTRAN TMPDIR environment variable for specifying a non default directory for files opened with STAT USZ SCRATCH is not used anymore Instead gfortran checks the POSIX GNU standard TMPDIR environment variable and if TMPDIR is not defined gfortran falls back to other methods to determine the directory for temporary files as
112. led Documentation valgrind 1 The manual page for the valgrind utility provides detailed information on how to use Valgrind To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 2 man valgrind Valgrind Documentation HTML documentation for Valgrind is located at opt rh devtoolset 2 root usr share doc devtoolset 2 valgrind 3 8 1 html index html Online Documentation Hat Enterprise Linux 6 provides more detailed information about using Valgrind to profile applications See Also 71 72 Red Hat Developer Toolset 2 x User Guide over the Red Hat Enterprise Linux system version of Valgrind and the version distributed in the previous release of Red Hat Developer Toolset executable Chapter 12 OProfile Chapter 12 OProfile OProfile is a low overhead system wide profiler that uses the performance monitoring hardware on the processor to retrieve information about the kernel and executables on the system such as when memory is referenced the number of level 2 cache L2 requests and the number of hardware interrupts received It consists of a configuration utility a daemon for collecting data and a number of tools that can be used to transform the data into a human readable form For a complete list of tools that are OProfile profiles an application without adding any instrumentation by recording the details of every nth event This allows it to consume fewer r
113. linespecs types Breakpoints are now set on all matching locations in all inferiors and will be updated according to changes in the inferior New inferior control commands skip function and skip file have been added These commands can be uses to skip certain functions and files when stepping The info threads command now displays the thread name as set by prct1 or pthread_setname_np In addition new commands thread name and thread find have been added The thread name command accepts a name as an argument and can be used to set the name of the current thread The thread find command accepts a regular expression and allows the user to find threads that match it GDB now provides support for reading and writing a new gdb index section The command gdb add index can be used to add gdb indexto a file which allows GDB to load symbols from that file faster Note that this feature is already present in Red Hat Enterprise Linux 6 1 and later The watch command has been adapted to accept Location as an optional argument Two new special values can now be used when specifying the current search path for libthread_db sdir represents the default system locations of shared libraries and pdir stands for the directory with the libthread that is used by the application A new command info macros has been added This command accepts linespec as an optional argument and can be used to display the definitions of macros at that linespec location Note that i
114. lity now supports a new command line option ignore build id to ignore differing build ID bits The new option verbose or 1 for short prints all differences The eu strip utility now recognizes a new command line option strip sections to remove section headers entirely The libdw library now has new functions dwarf next unit dwarf offdie types dwarf lineisa dwarf linediscriminator dwarf lineop index dwarf getlocation implicit pointer and dwarf aggregate size The eu addr21ine utility now recognizes a new command line option flags or F for short to print more DWARF line information details The libelf library now supports using more than 65536 program headers in a file In addition a new function e1f getphdrnum has been added The eu addr2line utility now accepts the section name option or j name for short in the interests of binutils compatibility libcpu Intel SSE4 disassembler support has been added The eu readelf utility now implements call frame information and exception handling dumping The e command line option has been added this is enabled implicitly by a 121 Red Hat Developer Toolset 2 x User Guide A 5 Changes in dwz Red Hat Developer Toolset 2 0 is distributed with dwz 0 11 which provides a number of bug fixes and enhancements over the version included in Red Hat Developer Toolset 1 1 Below is a comprehensive list of changes in this release A 5 1 Changes Since Red Hat Devel
115. lone of the Emacs text editor The ptype and whatis commands have been updated to accept an argument to control the type formatting The info proc command has been updated to work on some core files The cd command has been enhanced and no longer requires a directory path as its first argument When executed with no arguments the command now changes to the home directory GDB now uses GNU v3 ABI as the default C ABI This has been the default option for GCC since November 2000 The info tracepoints command has been enhanced to display installed on target or not installed on target for each non pending location of a tracepoint A new command fo has been added This commands serves as a shorter variant of the forward search command A new command catch signal has been added This command can be used to catch signals by their names and is similar to the handle command but also allows you to attach additional conditions or commands A new command maint info bfds has been added This command can be used to list all binary files BFDs opened by GDB Two new commands python interactive command and its shorter variant pi command have been added These commands allow you to start an interactive Python prompt or evaluate a Python command and print the results to standard output A new command py command has been added This command serves as a shorter variant of the python command command New enable type printer name an
116. lset binary tools as default scl enable devtoolset 2 bash To verify the version of binutils you are using at any point type the following at a shell prompt which objdump Red Hat Developer Toolset s obj dump executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset ob j dump objdump v 4 5 Additional Resources 40 Chapter 4 binutils A detailed description of binutils is beyond the scope of this book For more information see the resources listed below Installed Documentation as 1 Id 1 addr2line 1 ar 1 c filt 1 dwp 1 elfedit 1 gprof 1 nm 1 objcopy 1 objdump 1 ranlib 1 readelf 1 size 1 strings 1 strip 1 Manual pages for various binutils tools provide more information about their respective usage To display a manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 2 man tool Online Documentation binary tools and their usage See Also the Red Hat Enterprise Linux system version of binutils and the version distributed in the previous release of Red Hat Developer Toolset in C C and Fortran 41 Red Hat Developer Toolset 2 x User Guide Chapter 5 elfutils elfutils is a collection of various binary tools such as eu objdump eu readelf and other utilities Toolset version of elfutils Red Hat Developer Toolset i
117. luation SER0402 1 year Unsupported Partner Evaluation Red Hat Enterprise Linux SER0403 1 year Unsupported Red Hat Advanced Partner Subscription 1 4 1 Using RHN Classic If your system is registered with RHN Classic complete the following steps to subscribe to Red Hat Developer Toolset 1 Display a list of all channels that are available to you in order to determine the exact name of the Red Hat Developer Toolset channel To do so type the following at a shell prompt as root rhn channel available channels The name of the channel depends on the specific version of Red Hat Enterprise Linux you are using and is in the rhel architecture variant dts2 version format where architecture is the system s CPU architecture x86_64 or i386 variant is the Red Hat Enterprise Linux system variant server or workstation and version is the Red Hat Enterprise Linux system version 5 or 6 2 Subscribe the system to the Red Hat Developer Toolset channel by running the following command as root rhn channel add channel channel_name Replace channel_name with the name you determined in the previous step 3 To verify the list of channels you are subscribed to at any time run as root rhn channel list Classic see the Red Hat Subscription Management Guide 1 4 2 Using Red Hat Subscription Management If your system is registered with Red Hat Subscription Management complete the following steps to attach a subscription that provides a
118. march btver2 option A 2 2 Changes Since Red Hat Enterprise Linux 6 4 and 5 9 The following features have been added since the release of GCC included in Red Hat Enterprise Linux 6 4 and 5 9 A 2 2 1 Status and Features A 2 2 1 1 C 11 GCC 4 7 and later provides experimental support for building applications compliant with C 11 using the std c 11 or std gnu 11 command line options However there is no guarantee for compatibility between C 11 code compiled by different versions of the compiler Refer to The C runtime library libstdc supports a majority of the C 11 features However there is no or only partial support for some features such as certain properties on type traits or regular defined behavior Support for C 11 exception_ptr and future requires changes to the exception handling runtime in the system libstdc package These changes will be distributed through the normal Z stream channel Application of all Red Hat Enterprise Linux errata may be required to see correct runtime functionality when using these features A 2 2 1 2 C11 GCC 4 7 and later provides experimental support for some of the features from the C11 revision of the ISO C standard and in addition to the previous now deprecated std c1x and std gnu1x command line options gcc now accepts std c11 and std gnu11 Note that since this support is experimental it may change incompatibly in future releases Examples for features that are suppo
119. mation and you want the gdb utility to be capable of listing the entire source code you can run the following command to change the number of listed lines to 20 gdb set listsize 20 You can now display the entire source code of the file you are debugging by running the list command with no additional arguments gdb list 1 include lt stdio h gt 2 include lt limits h gt 3 4 int main int argc char argv 5 unsigned long int a 0 6 unsigned long int b 1 7 unsigned long int sum 8 9 while b lt LONG MAX 10 printf ld b 11 sum a 12 a b 13 b sum 14 15 16 return 0 17 50 Chapter 7 GNU Debugger GDB 7 5 Setting Breakpoints Setting a New Breakpoint To set a new breakpoint at a certain line run the following command break file name line number You can also set a breakpoint on a certain function break file name function name Example 7 5 Setting a New Breakpoint line 10 by running the following command gdb break 10 Breakpoint 1 at 0x4004e5 file fibonacci c line 10 Listing Breakpoints To display a list of currently set breakpoints run the following command info breakpoints Example 7 6 Listing Breakpoints display the list of currently set breakpoints by running the following command gdb info breakpoints Num Type Disp Enb Address What 1 breakpoint keep y 0x00000000004004e5 in main at fibonacci c 10 Deleting Existing Breakpoints To
120. me Stamps Chapter 8 strace Consider an executable file named pwd To run the strace utility on this file and include time stamps in the output type scl enable devtoolset 2 strace tt pwd 19 43 28 011815 execve pwd pwd 36 vars 0 19 43 28 012128 brk 0 0xcd3000 19 43 28 012174 mmap NULL 4096 PROT READ PROT WRITE MAP PRIVATE MAP ANONYMOUS 1 Ox7fc869cb0000 19 43 28 012427 open etc ld so cache O_RDONLY 3 19 43 28 012446 fstat 3 st_mode S_IFREG 0644 st size 61239 19 43 28 012464 mmap NULL 61239 PROT READ MAP PRIVATE 3 0 Ox7fc869ca1000 19 43 28 012483 close 3 0 19 43 28 013410 exited with 0 8 2 4 Displaying a Summary To display a summary of how much time was required to execute each system call how many times were these system calls executed and how many errors were encountered during their execution run the strace utility with the c command line option scl enable devtoolset 2 strace c program argument Example 8 4 Displaying a Summary Consider an executable file named 1sblk To run the strace utility on this file and display a trace summary type scl enable devtoolset 2 strace c lsblk gt dev null time seconds usecs call calls errors syscall 80 88 0 000055 1 106 16 open 19 12 0 000013 0 140 munmap 0 00 0 000000 0 148 read 0 00 0 000000 0 1 write 0 00 0 000000 0 258 close 0 00 0 000000 0 37 2 stat 100 00 0 000
121. ment This can be used to limit the functions selected by the supplied regular expression to those that are defined in the specified file Support for multi program Sometimes referred to as multi executable or multi exec debugging has been added In particular the GNU Debugger now supports the following commands The add inferior command can be used to add a new inferior The clone inferior command can be used to create a copy of an inferior with the same executable loaded The remove inferior command accepts an inferior ID as an argument and can be used to remove an inferior Support for trace state variables has been added In particular the GNU Debugger now supports the following commands The tvariable variable_name expression command can be used to define or modify a trace state variable The info tvariables command can be used to display a list of currently defined trace state variables and their values The delete tvariable variable_name command can be used to delete one or more trace state variables A new ftrace has been added This command accepts a function name a line number or an address as an argument and can be used to define a fast tracepoint at that location Support for disconnected tracing trace files and circular trace buffer has been added A new teval command has been added This command accepts one or more expressions to evaluate at a tracepoint The GNU Debugger has been adapted to parse the Ob prefix of bina
122. n order to do this the debugged program must be compiled with the g3 command line option to have 125 Red Hat Developer Toolset 2 x User Guide macro information available in it Anew command alias has been added This command can be used to create an alias of an existing command The info macro command now accepts all and as valid options To display a function parameter s entry value that is the value at the time of function entry the suffix entry can be added to the parameter GDB now displays entry values in backtraces if available New set print entry values and show print entry values commands have been added The set print entry values command accepts both compact default if needed no only and preferred as valid arguments and can be used to enable printing of function arguments at function entry The show print entry values command can be used to determine whether this feature is enabled New set debug entry values and show debug entry values commands have been added The set debug entry values command can be used to enable printing of debugging information for determining frame argument values at function entry and virtual tail call frames command has been added as an alias of shell command The watch command now accepts mask mask value as an argument This can be used to create masked watchpoints New set extended prompt and show extended prompt commands have been added The set extended prompt command enables s
123. n in order to print the number to standard output Now consider another source file named count C with the following contents Chapter 13 Dyninst include lt stdio h gt include lt fcntl h gt include BPatch h include BPatch_process h include BPatch_function h include BPatch_Vector h include BPatch_thread h include BPatch_point h void usage fprintf stderr Usage count lt process_id gt lt function gt n Global information for counter BPatch_variableExpr counter NULL void createCounter BPatch process app BPatch image appImage int zero 0 counter app gt malloc appImage gt findType int counter gt writeValue amp zero J bool interceptfunc BPatch_process app BPatch_image appImage char funcName BPatch_Vector lt BPatch_function gt func appImage gt findFunction funcName func if func size 0 fprintf stderr Unable to find function to instrument n exit 1 BPatch_Vector lt BPatch_snippet gt incCount BPatch_Vector lt BPatch_point gt points points func 0 gt findPoint BPatch_entry if points size 0 exit 1 BPatch_arithExpr counterPlusOne BPatch plus counter BPatch constExpr 1 BPatch arithExpr addCounter BPatch assign counter counterPlusOne return app gt insertSnippet addCounter points void printCount BPatch thread thread BPatch exitType int val 0 counter gt readValue amp v
124. name with a space separated list of meta packages you want to install For example to install only the Eclipse development environment and packages that depend on it type as root yum install devtoolset 2 ide 1 5 3 Installing Optional Packages Red Hat Developer Toolset is distributed with a number of optional packages that are not installed by default To list all Red Hat Developer Toolset packages that are available to you but not installed on your system type the following command at a shell prompt yum list available devtoolset 2 To install any of these optional packages run as root yum install package_name Replace package_name with a space separated list of packages that you want to install For example to install the devtoolset 2 gdb gdbserver and devtoolset 2 gdb doc packages type yum install devtoolset 2 gdb gdbserver devtoolset 2 gdb doc OP important _1_4_ _1_ _ amp __ m The devtoolset 2 gcc plugin devel package depends on the mpfr devel package which is only available in the Optional channel For detailed instructions on how to subscribe your system to 1 5 4 Installing Debugging Information To install debugging information for any of the Red Hat Developer Toolset packages make sure that the yum utils package is installed and run the following command as root debuginfo install package_name For example to install debugging information for the devtoolset 2 dwz package type debuginfo install
125. nd instead operator TIME is being looked up which results in a warning like error unable to find string literal operator operator _ TIME This applies to any string literal followed without white space by some macro T o fix this add some white space between the string literal and the macro name 108 Changes in Version 2 0 Taking the Address of Temporary Consider the following code struct Sf S Og aime ale y void bar S void foo bar amp S Previously an attempt to compile this code produced a warning message now it fails with an error This can be fixed by adding a variable and passing the address of this variable instead of the temporary The fpermissive compiler flag turns compile time errors into warnings and can be used as a temporary workaround Miscellaneous G now sets the predefined macro __cplusplus to the correct value 199711L for C 98 03 and 201103L for C 11 G now properly re uses stack space allocated for temporary objects when their lifetime ends which can significantly lower stack consumption for some C functions As a result of this some code with undefined behavior will now break When an extern declaration within a function does not match a declaration in the enclosing context G now properly declares the name within the namespace of the function rather than the namespace which was open just before the function definition G now implements the proposed resol
126. nd stops when a certain character is found It either returns a pointer to the byte following the last written byte or NULL if the given character is not found mempcpy Copies n bytes from one memory area to another and returns a pointer to the byte following the last written byte strcpy Copies a string from one memory area to another and returns a pointer to the second string stpcpy Copies a string from one memory area to another and returns a pointer to the terminating null byte of the second string strncpy Copies a maximum of n characters from one string to another and returns a pointer to the second string stpncpy Copies a maximum of n characters from one string to another It either returns a pointer to the terminating null byte of the second string or if the string is not null terminated a pointer to the byte following the last written byte strcat Appends one string to another while overwriting the terminating null byte of the second string and adding a new one at its end It returns a pointer to the new string strncat Appends a maximum of n characters from one string to another while overwriting the terminating null byte of the second string and adding a new one at its end It returns a pointer to the new string wmemcpy The wide character equivalent of the memcpy function that copies n wide characters from one array to another and returns a pointer to the second array wmempcpy The wide character equivalent of the mempc
127. nearby program headers in the program s memory image Changes Since Red Hat Enterprise Linux 5 9 The following features have been added since the release of binutils included in Red Hat Enterprise Linux 5 9 GNU Linux targets now support the STB GNU UNIQUE symbol binding a GNU extension to the standard set of ELF symbol bindings The binding is passed on to the dynamic linker which ensures that in the entire process there is only one symbol with the given name and type in use rc ammm The implementation of this feature depends on capabilities only found in newer versions of the glibc library Consequently this feature is currently available in Red Hat Developer Toolset for Red Hat Enterprise Linux 6 A new command line option no export dynamic has been added This option can be used to undo the effect of the E and export dynamic options A new command line option warn alternate em has been added This option can be used to display a warning if an ELF format object file uses an alternate machine code A new linker script function REGION ALIAS has been added This function can be used to create 116 Changes in Version 2 0 alias names of memory regions A new command line option Ttext segment address has been added for ELF based targets This option can be used to set the address of the first byte of the text segment A new linker script command INSERT has been added This command can be u
128. ng attributes such as const pure and noreturn to functions declared in header files Use the Wsuggest attribute const pure noreturn command line option to enable this Assembler code can now make use of a goto feature that allows for jumps to labels in C code 105 Red Hat Developer Toolset 2 x User Guide A 2 2 2 Language Compatibility In this section we describe the compatibility between the Red Hat Developer Toolset compilers and the Red Hat Enterprise Linux system compilers at the programming language level for example differences in the implementation of language standards such as C99 or changes to the warnings generated by Wall Some of the changes are a result of bug fixing and some old behaviors have been intentionally changed in order to support new standards or relaxed in standards conforming ways to facilitate compilation or runtime performance Some of these changes are not visible to the naked eye and will not cause problems when updating from older versions However some of these changes are visible and can cause grief to users porting to Red Hat Developer Toolset s version of GCC The following text attempts to identify major issues and suggests solutions A 2 2 2 1 C Constant expressions are now handled by GCC in a way that conforms to C90 and C99 For code expressions that can be transformed into constants by the compiler but are in fact not constant expressions as defined by ISO C this may cause warnings o
129. ng tool to monitor the activities of the entire system without the need to instrument recompile install and reboot Valgrind 3 8 1 An instrumentation framework and a number of tools to profile applications in order to detect memory errors identify memory management problems and report any use of improper arguments in system calls OProfile 0 9 8 A system wide profiler that uses the performance monitoring hardware on the processor to retrieve information about the kernel and executables on the system Dyninst 8 0 A library for instrumenting and working with user space executables during their execution a If you intend to develop applications for Red Hat JBoss Middleware or require support for OpenShift Tools it is recommended that you use Red Hat JBoss Developer Studio Red Hat Developer Toolset 2 x User Guide Red Hat Enterprise Linux in two important respects 1 Red Hat Developer Toolset can be used on multiple major and minor releases of Red Hat 2 Unlike Technology Preview compilers and other tools shipped in earlier Red Hat Enterprise Linux Red Hat Developer Toolset is fully supported under Red Hat Enterprise Linux Subscription Level Agreements is functionally complete and is intended for production use Important bug fixes and security errata are issued to Red Hat Developer Toolset subscribers in a similar manner to Red Hat Enterprise Linux for two years from the release of each major version release New major versio
130. ns can be recreated The new command set use deprecated index sections on causes GDB to use any older gdb index sections it finds If this option is set the ability to set breakpoints on inline functions is lost in symbol files with older gdb index sections The gdb index section has also been updated to record more information about each symbol GDB now provides Ada support for GDB MI Variable Objects GDB now supports breakpoint always inserted mode inthe record target gdbserver now supports evaluation of breakpoint conditions Note that you can instruct GDB to send the breakpoint conditions in bytecode form but gdbserver only reports the breakpoint trigger to GDB when its condition evaluates to true The z0 z1 breakpoint insertion packets have been extended to carry a list of conditional expressions over to the remote stub depending on the condition evaluation mode You can use the set remote conditional breakpoints packet command to control the use of this extension A new RSP packet QProgramSignals can be used to specify the signals the remote stub can pass to the debugged program without GDB involvement A new command info os has been added as the MI equivalent of info os Output logs such as set logging and related now include MI output New set use deprecated index sections on off and show use deprecated index sections on off commands have been added These commands allow you to control the use of deprecated gdb index sections
131. ns of Red Hat Developer Toolset is released annually providing significant updates for existing components and adding major new components A single minor release issued six months after each new major version release provides a smaller update of bug fixes security errata and new minor components Additionally the Red Hat Enterprise Linux Application Compatibility Specification also applies to Red Hat Developer Toolset Subject to some constraints on the use of newer C 11 language features detailed OP important _ 11_1_x _ m Applications and libraries provided by Red Hat Developer Toolset do not replace the Red Hat Enterprise Linux system versions nor are they used in preference to the system versions Using a framework called Software Collections an additional set of developer tools is installed into the opt directory and is explicitly enabled by the user on demand using the supplied sc1 utility 1 2 Main Features The Red Hat Developer Toolset version of the GNU Compiler Collection GCC provides the following features A new register allocator LRA has been added improving code performance A fast memory error detector called AddressSanitizer has been added A fast data race detector called ThreadSanitizer has been added Extremely large functions can now be compiled faster using less memory A new general optimization level has been introduced GCC diagnostic messages now highlight the exact problem source code Various new
132. number of new warnings that are either enabled by default or by using the Wall option Although these warnings do not result in a compilation failure on their own often Wall is 109 Red Hat Developer Toolset 2 x User Guide used in conjunction with Werror causing these warnings to act like errors This section provides a list of these new or newly enabled warnings Unless noted otherwise these warnings apply to both C and C The behavior of the wall command line option has changed and now includes the new warning flags Wunused but set variable and with wall Wextra Wunused but set parameter This may result in new warnings in code that compiled cleanly with previous versions of GCC For example consider the following code void fn void int foo foo bar foo is never used The following diagnostic output will be produced warning variable foo set but not used Wunused but set variable To fix this issue first see if the unused variable or parameter can be removed without changing the result or logic of the surrounding code If not annotate it with __attribute__ __unused__ Asa workaround you can use the Wno error unused but set variable or Wno error unused but set parameter command line option The Wenum compare option causes GCC to report a warning when values of different enum types are being compared Previously this option only worked for C programs but now it works for C as well
133. o in the current working directory 3 1 3 Running a C Program When gcc compiles a program it creates an executable binary file To run this program on the command line change to the directory with the executable file and type 31 Red Hat Developer Toolset 2 x User Guide Example 3 2 Running a C Program on the Command Line hello Hello World 3 2 GNU C Compiler 3 2 1 Installing the C Compiler In Red Hat Developer Toolset the GNU C compiler is provided by the devtoolset 2 gcc c package 3 2 2 Using the C Compiler To compile a C program on the command line run the g compiler as follows scl enable devtoolset 2 g o output file source file This creates a binary file named output file in the current working directory If the o option is omitted the g compiler creates a file named a out by default When you are working on a project that consists of several source files it is common to compile an object file for each of the source files first and then link these object files together This way when you change a single source file you can recompile only this file without having to compile the entire project To compile an object file on the command line run the following command scl enable devtoolset 2 g o object file c source file This creates an object file named object_file If the o option is omitted the g compiler creates a file named after the source file with the o file e
134. o sections The dwarf highpc function now handles the DWARF 4 DW AT high pc constant form The eu elflint utility now accepts executables produced by the gold linker The eu nm utility now supports C demangling The eu ar utility now supports a new modifier D for deterministic output with no UID GID or mtime info The U modifier is the inverse The eu readelf utility can now print SDT ELF notes SystemTap probes and the gdb index GDB section It can now also print DW OP GNU entry value and DW AT GNU call site families of DIE attributes The eu strip utility now recognizes a new command line option reloc debug sections A 4 3 Changes Since Red Hat Enterprise Linux 5 9 In addition to the above changes the following features have been added since the release of elfutils included in Red Hat Enterprise Linux 5 9 DWARF 4 is now supported As well support for DW OP GNU implicit pointer and STB GNU UNIQUE has been added The libdwf1 library now supports automatic decompression of files compressed with gzip bzip2 and lzma and of Linux kernel images made with gzip bzip2 or 1zma Files named with compression suffixes are searched for Linux kernel images Core file support was improved Support has been added for decoding DWARF CFI into location description form Support has been added for some new DWARF 3 expression operations which were previously omitted A new function dwfl dwarf line has been added The eu elfcmp uti
135. ol option file_name distributed with elfutils For example to use the eu obj dump tool to inspect an object file type scl enable devtoolset 2 eu objdump option object file 42 Chapter 5 elfutils Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset binary tools as default scl enable devtoolset 2 bash rammm To verify the version of elfutils you are using at any point type the following at a shell prompt which eu objdump Red Hat Developer Toolset s eu objdump executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset eu obj dump eu objdump V 5 3 Additional Resources A detailed description of elfutils is beyond the scope of this book For more information see the resources listed below See Also the Red Hat Enterprise Linux system version of elfutils and the version distributed in the previous release of Red Hat Developer Toolset shared libraries and ELF executables for size 43 Red Hat Developer Toolset 2 x User Guide Chapter 6 dwz dwz is a command line tool that attempts to optimize DWARF debugging information contained in ELF shared libraries and ELF executa
136. old Attributes on Labels A 2 1 3 Debugging Enhancements DWARF4 New gsplit dwarf Option A 2 1 4 C Changes Experimental C Features from an Upcoming Standard New thread_local Keyword Dynamic Initialization of Thread local Variables C 11 Attribute Syntax C 11 Alignment Specifier A 2 1 5 Fortran Changes A 2 1 5 1 Caveats A 2 1 5 2 ABI Compatibility A 2 1 5 3 Other Changes BACKT RACE Intrinsic Floating Point Numbers with q as Exponential GFORTRAN_TMPDIR Environment Variable Fortran 2003 TS 29113 A 2 1 6 x86 specific Improvements New Instructions New Built in Functions to Detect Run time CPU Type and ISA Function Multiversioning New RTM and HLE Intrinsics 85 86 87 89 89 89 89 90 90 91 91 91 92 92 93 93 93 93 94 94 94 94 94 94 94 94 95 95 95 95 95 95 96 96 96 96 96 96 96 96 97 97 97 97 97 97 97 98 98 98 98 99 Transactions Using Transactional Synchronization Extensions Support for AMD Family 15h Processors Support for AMD Family 16h Processors A 2 2 Changes Since Red Hat Enterprise Linux 6 4 and 5 9 A 2 2 1 Status and Features A 2 2 1 1 C 11 A 2 2 1 2 C11 A 2 2 1 3 Parallelism and Concurrency C 11 Types and GCC Built ins for Atomic Memory Access Transactional Memory A 2 2 1 4 Architecture specific Options A 2 2 1 5 Link time Optimization A 2 2 1 6 Miscellaneous A 2 2 2 Language Compatibility A 2 2 2 1 C Duplicate Member A 2 2 2 2 C Header Dependency Ch
137. oolset nn 1 1 About Red Hat Developer Toolset 1 2 Main Features 1 3 Compatibility 1 4 Getting Access to Red Hat Developer Toolset 1 4 1 Using RHN Classic 1 4 2 Using Red Hat Subscription Management 1 5 Installing Red Hat Developer Toolset 1 5 1 Installing All Available Components 1 52 Installing Individual Package Groups 1 5 3 Installing Optional Packages 1 5 4 Installing Debugging Information 1 6 Updating Red Hat Developer Toolset 1 6 1 Updating to a Minor Version 1 6 2 Updating to a Major Version 1 7 Uninstalling Red Hat Developer Toolset 1 8 Additional Resources Online Documentation See Also Part Il Integrated Development Environments 00 0 cette Chapter2 Eclipse ud eoe ce telum Cael uv eei ix eb hee fl ehi 2 1 Installing Eclipse 2 1 1 Building Eclipse from the Source RPM Packages 2 2 Using Eclipse 2 2 1 Using the Red Hat Developer Toolset Toolchain 2 2 2 Using the Red Hat Enterprise Linux T oolchain 2 3 Additional Resources Installed Documentation Online Documentation See Also Part Ill Development T 001S hr aas Chapter 3 GNU Compiler Collection GCC 000s 3 1 GNU C Compiler 3 1 1 Installing the C Compiler 3 1 2 Using the C Compiler 3 1 3 Running a C Program 3 2 GNU C Compiler 3 2 1 Installing the C Compiler 13 13 14 15 16 17 17 18 19 19 20 20 21 21 21 21 22 22 22 Red Hat Developer Toolset 2 x User Guid
138. oper Toolset 1 1 The following features have been added since the release of dwz included in Red Hat Developer Toolset 1 1 The DW_FORM_data4 DW_FORM_data8 and DW AT high pc attributes have been optimized The dwz utility now allocates more memory when recomputing abbreviations and no longer terminates unexpectedly The dwz utility no longer crashes when processing debugging information that contains several copies of the same Debugging Information Entry DIE within the same compilation unit The dwz utility no longer writes an incorrect DW FORM code for a compilation unit version The dwz utility now supports version 8 of the gdb index section A 6 Changes in GDB Red Hat Developer Toolset 2 0 is distributed with GDB 7 6 which provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version and the version included in Red Hat Developer Toolset 1 1 Below is a comprehensive list of new features in this release A 6 1 Changes Since Red Hat Developer Toolset 1 1 The following features have been added since the release of GDB included in Red Hat Developer Toolset 1 1 Target record has been renamed to record full Consequently you can now use the record full command to record or replay an execution log In addition the following commands have been renamed The set record insn number max and show record insn number max commands have been renamed to set record full insn number max and show r
139. optimization options have been added DWARF4 is now used as the default debug format GCC now fully implements the C 11 language standard C 11 library support has been extended though is still experimental GCC now supports dynamic initialization of thread local variables Support has been added for Intel FXSR XSAVE and XSAVEOPT instructions New built in functions added to detect run time Intel CPU Type and ISA Intel function multi versioning support added Intel RTM HLE intrinsics built ins and code generation have been added 14 Chapter 1 Red Hat Developer Toolset Transactions the fgnu tm option can now be run using Intel TSX extensions Support for AMD family 15h and 16h processors has been added Various Fortran changes have been included The version of the GNU Debugger GDB included in Red Hat Developer Toolset provides the following features Improved and expanded support for Python scripting Improved handling of C debugee executables Improved inferior control commands Improved support for ambiguous line specifications Improved tracepoint support Multi program debugging Additionally the Red Hat Developer Toolset version of binutils provides these features The new gold linker which is smaller and faster than 1d Note that gold is not the default linker and must be explicitly enabled by using the alternatives command Support for link time optimization LTO in conjunction with GCC Support for build
140. ores barriers and condition variables In addition Helgrind now supports annotations to describe thread safe reference counted heap objects A new command line option show possibly lost has been added to Memcheck By default this option is enabled and causes the leak detector to show possibly lost blocks A new experimental heap profiler DHAT Dynamic Heap Analysis Tool has been added DHAT keeps track of allocated heap blocks and also inspects every memory reference to see which block if any is being accessed This gives a lot of insight into block lifetimes utilization turnover liveness and the location of hot and cold fields You can use DHAT to do hot field profiling Support for unfriendly self modifying code has been improved and the extra overhead incurred by smc check all1 has been reduced by approximately a factor of 5 as compared with the previous version of Valgrind A new command line option fullpath after has been added This option can be used to display directory names for source files in error messages and is combined with a flexible mechanism for specifying which parts of the paths should be shown A new command line option require text symbol has been added This option stops the execution if a specified symbol is not found in a given shared object when loaded into the process As a result working with function intercepting and wrapping is now safer and more reliable Valgrind now implements more reliable s
141. ous standard C string functions such as strlen strchr strcpy strcat and stpcpy as well as their respective FORTIFY SOURCE variants by transforming them into custom faster code This means that there might be fewer or other calls to those functions than in the original source code The optimization is enabled by default at 02 or higher optimization levels It is disabled when using fno optimize strlen or when optimizing for size When compiling for 32 bit GNU Linux and not optimizing for size fomit frame pointer is now enabled by default The prior default setting can be chosen by using the fno omit frame pointer command line option Floating point calculations on x86 targets and in strict C99 mode are now compiled by GCC with a stricter standard conformance This might result in those calculations executing significantly slower It can be disabled using fexcess precision fast A 2 2 4 Debugging Compatibility GCC now generates DWARF debugging information that uses more or newer DWARF features than previously GDB contained in Red Hat Developer Toolset can handle these features but versions of GDB older than 7 0 cannot GCC can be restricted to only generate debugging information with older DWARF features by using the gdwarf 2 gstrict dwarf or gdwarf 3 gstrict dwarf options the latter are handled partially by versions of GDB older than 7 0 Many tools such as Valgrind SystemTap or third party debuggers utilize debugging
142. provide support for the AMD Family 15h processors models 02h and 10 1fh Changes Since Red Hat Enterprise Linux 6 4 The following features have been added since the release of binutils included in Red Hat Enterprise Linux 6 4 The readelf and objdump tools can now display the contents of the debug macro sections New dwarf start and dwarf end command line options have been added to the readelf and objdump tools These options are used by the new Emacs mode see the dwarf mode el file A new interleave width command line option has been added to the obj copy tool to allow the use of the interleave to copy a range of bytes from the input to the output A new dyn syms command line option has been added to the readelf tool This option can be used to dump dynamic symbol table A new tool elfedit has been added to binutils This tool can be used to directly manipulate ELF format binaries A new command line option addresses or a for short has been added to the addr2line tool This option can be used to display addresses before function and source file names A new command line option pretty print or p for short has been added to the addr2line tool This option can be used to produce human readable output Support for dwz m optimized debug information has been added The devtoolset 2 binutils devel package now provides the demangle h header file Changes Since Red Hat Enterprise Linux 5 9 The following feature
143. ption The default option auto chooses the most efficient available mode New set dprintf style gdb call agent and show dprintf style commands have been added These commands allow you to control the way in which a dynamic printf is performed the gdb option requests a GDB printf command call causes dprintf to call a function in the inferior and agent requests that the target agent such as gdbserver does the printing New set dprintf function expression show dprintf function set dprintf channel expression and show dprintf channel commands have been added These commands allow you to set the function and optional first argument to the call when using the call style of dynamic printf New set disconnected dprintf on off and show disconnected dprintf commands have been added These commands allow you to control whether agent style dynamic printfs continue to be in effect after GDB disconnects The following changes have been made to the C language support since the release of the GNU Debugger included in Red Hat Enterprise Linux 6 2 When debugging a template instantiation parameters of the template are now put in scope The following changes have been made to the Python scripting support since the release of the GNU Debugger included in Red Hat Enterprise Linux 6 2 The register_pretty_printer function in module gdb printing now takes an optional replace argument The maint set python print stack on off command has been depreca
144. ption performs pointer association checks in calls but does not handle undefined pointers nor pointers in expressions The fcheck all option enables all of the above options A new command line option fno protect parens has been added This option allows the compiler to reorder REAL and COMPLEX expressions with no regard to parentheses When OpenMP s WORKSHARE is used array assignments and WHERE will now be run in parallel More Fortran 2003 and Fortran 2008 mathematical functions can now be used as initialization expressions The GCC compiler directive now enables support for some extended attributes such as STDCALL A 2 2 2 4 2 Compatibility Changes The Ofast command line option now automatically enables the fno protect parens and fstack arrays flags Front end optimizations can now be disabled by the fno frontend optimize option and selected by the ffrontend optimize option The former is essentially only desirable if invalid Fortran source code needs to be compiled for example when functions as compared to subroutines have side effects or to work around compiler bugs The GFORTRAN USE STDERR environment variable has been removed and GNU Fortran now always prints error messages to standard error The fdump core command line option and the GFORTRAN ERROR DUMPCORE environment variable have been removed When encountering a serious error GNU Fortran now always aborts the execution of the program The fbacktrace command line
145. py function that copies n wide characters from one array to another and returns a pointer to the byte following the last written wide character wcscpy The wide character equivalent of the strcpy function that copies a wide character string from one array to another and returns a pointer to the second array wcsncpy The wide character equivalent of the strncpy function that copies a maximum of n wide characters from one array to another and returns a pointer to the second string wcscat The wide character equivalent of the strcat function that appends one wide character string to another while overwriting the terminating null byte of the second string and adding a new one at its end It returns a pointer to the new string wcsncat The wide character equivalent of the strncat function that appends a maximum of n wide characters from one array to another while overwriting the terminating null byte of the second wide character string and adding a new one at its end It returns a pointer to the new string o N Chapter 9 memstomp 9 1 Installing memstomp In Red Hat Developer Toolset the memstomp utility is provided by the devtoolset 2 memstomp package 9 2 Using memstomp To run the memstomp utility on a program you want to analyze type the following at a shell prompt scl enable devtoolset 2 memstomp program argument To immediately terminate the analyzed program when a problem is detected run the utility with the
146. r errors ll formed redeclarations of library functions are no longer accepted by the compiler In particular a function with a signature similar to the built in declaration of a library function for example abort or memcpy must be declared with extern C to be considered as a redeclaration otherwise it is ill formed Duplicate Member Consider the following struct declaration Sure A T cue Fap Union X Siirlieie p eds ele he Ns do Previously this declaration used to be diagnosed just by the C compiler now it is also diagnosed by the C compiler Because of the anonymous unions and structs there is ambiguity about what a actually refers to and one of the fields therefore needs to be renamed A 2 2 2 2 C Header Dependency Changes lt iostream gt lt string gt and other STL headers that previously included lt unistd h gt as an implementation detail to get some feature macros for gthr h purposes no longer do so because it was a C standard violation This can result in diagnostic output similar to the following error truncate was not declared in this scope error sleep was not declared in this scope error pipe was not declared in this scope error there are no arguments to offsetof that depend on a template parameter so a declaration of offsetof must be available To fix this add the following line early in the source or header files that need it include lt unistd h gt Many of the st
147. ramming language 2 1 1 Building Eclipse from the Source RPM Packages It is recommended that you install the Red Hat Developer Toolset version of Eclipse from the official RPM packages distributed by Red Hat If for some reason you need to build Red Hat Developer Toolset 2 0 Eclipse on Red Hat Enterprise Linux 6 from the supplied source RPM SRPM packages complete the following steps 1 Install the java 1 7 0 openjdk package from Red Hat Enterprise Linux 6 3 or newer and all its dependencies 2 Download build and install the maven package and all its dependencies from the SRPM packages for Fedora 19 3 Download build and install the tycho package and all its dependencies from the SRPM packages for Fedora 19 4 Download and build all dependent packages listed in the devtoolset 2 eclipse SRPM package 5 Download and build the devtoolset 2 eclipse SRPM package 6 Download and build additional devtoolset 2 eclipse SRPM packages 2 2 Using Eclipse To start the Red Hat Developer Toolset version of Eclipse either select Applications Programming DTS Eclipse from the panel or type the following at a shell prompt scl enable devtoolset 2 eclipse During its startup Eclipse prompts you to select a workspace that is a directory in which you want to store your projects You can either use workspace which is the default option or click the Browse button to browse your file system and select a custom directory Addi
148. record constant addresses in unwind tables without runtime relocation A new command line option msse check none error warning has been added for x86 targets The a command line option now accepts g as a valid sub option This combination can be used to enable assembly listings with additional information about the assembly including the list of supplied command line options or the assembler version A new command line option msse2avx has been added for x86 targets This option can be used to encode SSE instructions with VEX prefix x86 targets now support the Intel XSAVE EPT MOVBE AES PCLMUL and AVX FMA instructions New command line options march cpu extension mtune cpu mmnemonic att intel msyntax att intel mindex reg mnaked reg and mold gcc have been added for x86 targets New pseudo operations string16 string32 and string64 have been added These pseudo operations be used to generate wide character strings The i386 port now supports the SSE5 instruction set A new pseudo operation reloc has been added This pseudo operation serves as a low level 118 Changes in Version 2 0 interface for creating relocations A 3 3 Other Binary Tools A 3 3 1 New Features Changes Since Red Hat Developer Toolset 1 1 The following features have been added since the release of binutils included in Red Hat Developer Toolset 1 1 A manual page for the dwp utility has been added The binary tools now
149. release of GDB included in Red Hat 124 Changes in Version 2 0 Table A 3 New Remote Packets Remote Packet Description QTBuf fer size Sets the size of the trace buffer The remote stub reports support for this packet to the qSupported query Qbtrace bts Enables branch tracing based on Branch Trace Store BT S for the current thread The remote stub reports support for this packet to the qSupported query Qbtrace off Disables branch tracing for the current thread The remote stub reports support for this packet to the qSupported query qXfer btrace read Reads the traced branches for the current thread The remote stub reports support for this packet to the qSuppor ted query qXfer libraries The previously unused annex of the qXfer libraries svr4 read s annex svr4 read packet is now used to support passing of an argument list The remote stub reports support for this argument list to the qSupported query The defined arguments are start and prev These arguments are used to reduce work necessary for updating the library list and significantly speed up the process A 6 2 Changes Since Red Hat Enterprise Linux 6 4 The features below have been added since the release of GDB included in Red Hat Enterprise Linux 64 New Features Support for linespecs has been improved in particular a more consistent handling of ambiguous linespecs some support for labels in the program s source and FILE LINE support now extends to further
150. rted are Unicode strings including the predefined macros 100 Changes in Version 2 0 STDC UTF 16 and _ STDC_UTF_32__ nonreturning functions Noreturn and lt stdnoreturn h gt and alignment support Alignas Alignof max align t and lt stdalign h gt A 2 2 1 3 Parallelism and Concurrency GCC 4 7 and later provides improved support for programming parallel applications 1 The GCC compilers support the OpenMP API specification for parallel programming version 3 1 2 The C 11 and C11 standards provide programming abstractions for multi threaded programs The respective standard libraries include programming abstractions for threads and thread related features such as locks condition variables or futures These new versions of the standard also define a memory model that precisely specifies the runtime behavior of a multi threaded program such as the guarantees provided by compilers and the constraints programmers have to pay attention to when writing multi threaded programs Note that support for the memory model is still experimental see below for details For more 1 5C 11 and The rest of this section describes two new GCC features in more detail Both these features make it easier for programmers to handle concurrency such as when multiple threads do not run truly in parallel but instead have to synchronize concurrent access to shared state and both provide atomicity for access to memory but differ in their s
151. ry numbers exactly the same way as the GNU Compiler Collection The GNU Debugger now supports the following commands for process record and replay New commands set record memory and show record memory have been added The set record memory command accepts on or of f as an argument and can be used to enable or disable stopping the inferior when a memory change of the next instruction cannot be recorded Use the show record memory query command to determine whether this feature is enabled A new command record save has been added This command accepts a file name as an argument and can be used to save the execution log to a file A new command record restore has been added This command accepts a file name as an argument and can be used to restore the execution log from a file A new command eval has been added This command accepts a format string followed by one or more arguments transforms it to a command and then executes it A new command save breakpoints has been added This command accepts a file name as an argument and can be used to store all currently defined breakpoints to a file To restore the saved breakpoints from this file use the source command New commands set may write registers set may write memory set may insert breakpoints set may insert tracepoints set may insert fast tracepoints and Red Hat Developer Toolset 2 x User Guide set may interrupt have been added All of these commands accept either on or off as an argument and
152. s To generate the report run as root sosreport Account and Contact Information In order to help you GSS requires your account information to customize their support as well contact information to get back to you When you contact GSS ensure you have your Red Hat customer number or Red Hat Network RHN login name Company name Contact name Preferred method of contact phone or email and contact information phone number or email address 89 Red Hat Developer Toolset 2 x User Guide Issue Severity Determining an issue s severity is important to allow the GSS team to prioritize their work There are four levels of severity Severity 1 urgent A problem that severely impacts your use of the software for production purposes It halts your business operations and has no procedural work around Severity 2 high A problem where the software is functioning but production is severely reduced It causes a high impact to business operations and no work around exists Severity 3 medium A problem that involves partial non critical loss of the use of the software There is a medium to low impact on your business and business continues to function by utilizing a work around Severity 4 low A general usage question report of a documentation error or a recommendation for a future product improvement For more information on determining the severity level of an issue see that you need your Red Hat login details in ord
153. s distributed with elfutils 0 155 This version is more recent than the version included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements Table 5 1 Tools Included in elfutils for Red Hat Developer Toolset Name Description eu addr2line Translates addresses into file names and line numbers eu ar Creates modifies and extracts files from archives eu elfcmp Compares relevant parts of two ELF files for equality eu elflint Verifies that ELF files are compliant with the generic ABI JABI and processor specific supplement ABI psABI specification eu findtextrel Locates the source of text relocations in files eu make debug Creates an offline archive for debugging archive eu nm Lists symbols from object files eu objdump Displays information from object files eu ranlib Generates an index to the contents of an archive to make access to this archive faster eu readelf Displays information about ELF files eu size Lists section sizes of object or archive files eu strings Displays printable character sequences in files eu strip Discards all symbols from object files eu unstrip Combines stripped files with separate symbols and debug information 5 1 Installing elfutils In Red Hat Developer Toolset elfutils is provided by the devtoolset 2 elfutils package and is 5 2 Using elfutils To execute any of the tools that are part of elfutils run the command as follows scl enable devtoolset 2 to
154. s have been added since the release of binutils included in Red Hat Enterprise Linux 5 9 A new command line option insn width width has been added to the obj dump tool This option can be used to specify the number of bytes to be displayed on a single line when disassembling instructions A new command line option relocated dumpzname number has been added to the readelf tool This option can be used to display the relocated contents of a section as a sequence of bytes A new command line option external symbols table filename has been added to the gprof tool This option can be used to read a symbol table from a certain file bfd now supports a plugin target which can be used to get basic support for new file formats by having the plugin target load the same shared objects used by gold The dwarf or W for short command line option of the obj dump tool has been adapted to be as flexible as the debug dump or w option of readelf 119 Red Hat Developer Toolset 2 x User Guide New command line options prefix prefix and prefix strip level have been added to the obj dump tool These options can be used to add absolute paths for the source or S for short option A new command line option wL has been added to the readelf tool This option can be used to dump decoded contents of the debug line section Thin archives are now supported Instead of containing object files such archives contain just pathnames pointing
155. sed to augment the default script In a linker script input section it is now possible to specify a file within an archive by using the archive file syntax The sort common command line option now accepts ascending and descending as optional arguments This can be used to specify which sorting order to use A new command line option build id has been added for ELF based targets This option can be used to generate a unique per binary identifier embedded in a note section A new command line option default script file_name or dT file name has been added This option can be used to specify a replacement for the built in linker script A new command line option Bsymbolic functions has been added When creating a shared library this option will cause references to global function symbols to be bound to the definitions with the shared library if such exist The new command line options dynamic list cpp new and dynamic list data have been added which can be used to modify the dynamic list A 3 1 2 Compatibility Changes Changes Since Red Hat Enterprise Linux 6 4 The following compatibility changes have been made since the release of binutils included in Red Hat Enterprise Linux 6 4 The copy dt needed entries command line option is no longer enabled by default Instead no copy dt needed entries is now the default option Evaluation of linker script expressions has been significantly improved Note that this can negativ
156. sion with Red Hat Developer Toolset gcc as default scl enable devtoolset 2 bash 30 Chapter 3 GNU Compiler Collection GCC K To verify the version of gcc you are using at any point type the following at a shell prompt which gcc Red Hat Developer Toolset s gcc executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset gcc E important Some newer library features are statically linked into applications built with Red Hat Developer Toolset to support execution on multiple versions of Red Hat Enterprise Linux This adds a small additional security risk as normal Red Hat Enterprise Linux errata would not change this code If the need for developers to rebuild their applications due to such an issue arises Red Hat will signal this via a security erratum Developers are strongly advised not to statically link their entire application for the same reasons Example 3 1 Compiling a C Program on the Command Line Consider a source file named hello c with the following contents include lt stdio h gt int main int argc char argv printf Hello World n return 0 j To compile this source code on the command line by using the gcc compiler from Red Hat Developer Toolset type scl enable devtoolset 2 gcc o hello hello c This creates a new binary file called hell
157. ssors mabm Enables the use of the popcnt and 1zcnt instructions on AMD processors mpopcnt Enables the use of the popcnt instruction on both AMD and Intel processors ANA 104 Changes in Version 2 0 When using the x87 floating point unit GCC now generates code that conforms to ISO C99 in terms of handling of floating point excess precision This can be enabled by fexcess precision standard and disabled by fexcess precision fast This feature is enabled by default when using standards conformance options such as std c99 Vectors of type vector long long or vector long are passed and returned using the same method as other vectors with the VSX instruction set Previously GCC did not adhere to the ABI for 128 bit vectors with 64 bit integer base types See GCC PR 48857 The mrecip command line option has been added which indicates whether the reciprocal and reciprocal square root instructions should be used The mveclibabi mass command line option has been added This can be used to enable the compiler to auto vectorize mathematical functions using the Mathematical Acceleration Subsystem library The msingle pic base command line option has been added which instructs the compiler to avoid loading the PIC base register in function prologues The PIC base register must be initialized by the runtime system The mblock move inline limit command line option has been added which enables the user to control the maximum size of
158. struct can now expect hidden visibility for std vector my hidden struct symbols As a result users that compile with the fvisibility hidden command line option should be aware of the visibility of types included from the library headers used If the header does not explicitly control symbol visibility types from those headers will be hidden along with instantiations that use those types For instance consider the following code include lt vector gt template std vector has default visibility include lt ctime gt struct tm has hidden visibility template class std vector lt tm gt instantiation has hidden visibility One approach to adjusting the visibility of a library header lt foo h gt is to create a forwarding header on the I include path consisting of the following pragma GCC visibility push default include_next lt foo h gt pragma GCC visibility push User defined Literal Support When compiling C with the std c 11 c 0x gnu 11 gnu 0x command line option GCC 4 7 0 and later unlike older versions supports user defined literals which are incompatible with some valid ISO C 03 code In particular white space is now needed after a string literal before something that could be a valid user defined literal Consider the following code const char p foobar TIME In C 03 the TIME macro expands to some string literal and is concatenated with the other one In C 11 __TIME__ is not expanded a
159. t argument Non pointer variables with the TARGET attribute can now be used as an actual argument to POINTER dummies with INTENT IN Pointers that include procedure pointers and those in a derived type pointer components can now also be initialized by a target instead of only by NULL The EXIT statement with construct name can now be used to leave the ASSOCIATE BLOCK IF SELECT CASE and SELECT TYPE constructs in addition to DO Internal procedures can now be used as actual arguments The named constants INTEGER_KINDS LOGICAL_KINDS REAL_KINDS and CHARACTER_KINDS of the intrinsic module ISO_FORTRAN_ENV have been added These arrays contain the supported kind values for the respective types The C_SIZEOF module procedures of the ISO_C_BINDINGS intrinsic module and the COMPILER_VERSION and COMPILER_OPTIONS module procedures of the ISO_FORTRAN_ENV intrinsic module have been implemented The OPEN statement now supports the NEWUNIT option This option returns a unique file unit and therefore prevents inadvertent use of the same unit in different parts of the program Unlimited format items are now supported 113 Red Hat Developer Toolset 2 x User Guide The INT 8 16 32 and REAL 32 64 128 format for ISO_FORTRAN_ENV intrinsic module type parameters are now supported It is now possible to use complex arguments with the TAN SINH COSH TANH ASIN ACOS and AT AN functions Additionally the new functions ASINH ACOSH and AT
160. t f int i return i j int main return t 1 j The following diagnostics output will be produced In instantiation of int t T with T int required from here error f was not declared in this scope and no declarations were found by argument dependent lookup at the point of instantiation fpermissive note int f int declared here later in the translation unit To correct the error in this example move the declaration of function f before the definition of template function t The fpermissive compiler flag turns compile time errors into warnings and can be used as a temporary workaround 107 Red Hat Developer Toolset 2 x User Guide Uninitialized const Consider the following declaration struct A int a A struct B public A Y const B b An attempt to compile this code now fails with the following error error uninitialized const b fpermissive note const struct B has no user provided default constructor This happens because B does not have a user provided default constructor Either an initializer needs to be provided or the default constructor needs to be added Visibility of Template Instantiations The ELF symbol visibility of a template instantiation is now properly constrained by the visibility of its template arguments For instance users that instantiate standard library components like std vector with hidden user defined types such as struct my hidden
161. tack unwinding on amd64 linux particularly in the presence of function wrappers and with gcc 4 5 compiled code Valgrind now implements modest scalability performance improvements for very large long running applications Valgrind now provides improved support for analyzing programs that are running in Wine Users can now include the valgrind valgrind h valgrind memcheck h and valgrind drd h header files in Windows programs that are compiled with MinGW or one of the Microsoft Visual Studio compilers Revision History Revision History Revision 1 0 2 Tue 10 Sep 2013 Jaromir Hradilek Red Hat Developer Toolset 2 0 GA release of the User Guide Revision 1 0 1 Tue 06 Aug 2013 Jaromir Hradilek Red Hat Developer Toolset 2 0 Beta 2 release of the User Guide Revision 1 0 0 Tue 28 May 2013 Jaromir Hradilek Red Hat Developer Toolset 2 0 Beta 1 release of the User Guide Index ABI compatibility ABI Compatibility addr2line features New Features application binary interface see ABI ar overview binutils as see GNU assembler assembling see GNU assembler bfd features New Features binutils C programming language 137 Red Hat Developer Toolset 2 x User Guide D 138 C 11 see GNU Compiler Collection c filt C11 see GNU Compiler Collection Cachegrind Callgrind compiling see GNU Compiler Collection Customer Portal Connect menu The Connect Menu debugging see GNU Debugger De
162. tandard C 11 atomic 3 1 GNU C Compiler 3 1 1 Installing the C Compiler In Red Hat Developer Toolset the GNU C compiler is provided by the devtoolset 2 gcc package and is 3 1 2 Using the C Compiler To compile a C program on the command line run the gcc compiler as follows scl enable devtoolset 2 gcc o output_file source_file This creates a binary file named output_file in the current working directory If the o option is omitted the compiler creates a file named a out by default When you are working on a project that consists of several source files it is common to compile an object file for each of the source files first and then link these object files together This way when you change a single source file you can recompile only this file without having to compile the entire project To compile an object file on the command line run the following command scl enable devtoolset 2 gcc o object file c source file This creates an object file named object_file If the o option is omitted the compiler creates a file named after the source file with the o file extension To link object files together and create a binary file run scl enable devtoolset 2 gcc o output file object file Note that you can execute any command using the sc l utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell ses
163. ted and will be deleted in GDB 7 5 The new command set python print stack none full message has replaced it A prompt substitution hook prompt_hook is now available to the Python API A new Python module gdb prompt has been added to the GDB Python modules library Python commands and convenience functions located in data directory python gdb command and data directory python gdb function are now automatically loaded on GDB start up Blocks now provide four new attributes global block static block is static and is global The gdb breakpoint function has been deprecated in favor of gdb breakpoints A new class gdb FinishBreakpoint is provided Type objects for struct and union types now allow access to the fields using standard Python Changes in Version 2 0 dictionary mapping methods A new event gdb new_obj file has been added A new function deep_items has been added to the gdb types module The function gdb Write now accepts an optional keyword stream Parameters can now be sub classed in Python which allows for implementation of the get_set_doc and get_show_doc functions Symbols Symbol Table Symbol Table and Line Object Files Inferior Inferior Thread Blocks and Block Iterator APIs now have an is_valid method Breakpoints can now be sub classed in Python which allows for implementation of the stop function that is executed each time the inferior reaches that breakpoint A new function gdb 1ookup global symbol
164. temTap Beginners Guide for Red Hat Enterprise Linux 76 Chapter 13 Dyninst 13 2 2 Using Dyninst as a Stand alone Application Before using the Dyninst library as a stand alone application set the value of the DYNINSTAPI RT LIB environment variable to the path to the runtime library file If you are running a 64 bit system you can do so by typing the following at a shell prompt export DYNINSTAPI RT LIB opt rh devtoolset 2 root usr lib64 dyninst libdyninstAPI RT so 8 0 If you are running a 32 bit system type export DYNINSTAPI RT LIB opt rh devtoolset 2 root usr lib dyninst libdyninstAPI RT so 8 0 This sets the DYNINSTAPI RT LIB environment variable in the current shell session to monitor the execution of a user space process For a detailed explanation of how to use Dyninst see the resources listed in Section 13 3 Additional Resources 77 78 Red Hat Developer Toolset 2 x User Guide Example 13 1 Using Dyninst as a Stand alone Application Consider a source file named exercise C that has the following contents include lt stdio h gt void print_iteration int value printf Iteration number d n value int main int argc char argv int i printf Enter the starting number scanf d amp i for i 0 i print iteration i return 0 This program prompts the user to enter a starting number and then counts down to 1 calling the print iteration function for each iteratio
165. tional Resources Installed Documentation Online Documentation See Also Part VI Getting Helpe mecs oe tibus lalla ciega Chapter 14 Accessing Red Hat Product Documentation cece aes Red Hat Developer Toolset Red Hat Enterprise Linux Chapter 15 Accessing the Customer Portal s eee 56 57 58 59 59 59 60 61 63 63 65 65 65 66 67 67 67 68 68 68 69 70 70 70 71 71 71 71 73 73 73 74 74 74 75 76 76 76 76 77 81 81 82 82 83 84 84 84 Red Hat Developer Toolset 2 x User Guide 15 1 The Plan Menu i 15 2 The Deploy Menu 15 3 The Connect Menu Chapter 16 Contacting Global Support Services 16 1 Gathering Required Information Background Information Diagnostics Account and Contact Information Issue Severity 16 2 Escalating an Issue 16 3 Re opening a Service Request 16 4 Additional Resources Online Documentation Changes in Versian 2 0 nra A 1 Changes in Eclipse A 1 1 Changes Since Red Hat Enterprise Linux 6 4 A 2 Changes in GCC A 2 1 Changes Since Red Hat Developer Toolset 1 1 A 2 1 1 Caveats Aggressive Loop Optimizations A 2 1 2 General Improvements and Changes New Local Register Allocator AddressSanitizer ThreadSanitizer Compiling Extremely Large Functions New Og Optimization Level Caret Diagnostic Messages New fira hoist pressure Option New fopt info Option New floop nest optimize Option Hot and C
166. tionally you can select the Use this as the default and do not ask again check box to prevent Eclipse from displaying this dialog box the next time you run this development environment When you are done click the OK button to confirm the selection and proceed with the startup 2 2 1 Using the Red Hat Developer Toolset Toolchain To use the Red Hat Developer Toolset version of Eclipse with support for the GNU Compiler Collection and binutils from Red Hat Developer Toolset make sure that the devtoolset 2 toolchain package is Eclipse uses the Red Hat Developer Toolset toolchain by default For detailed instructions on how to install the devtoolset 2 toolchain package in your system see 26 Chapter 2 Eclipse Or important If you are working on a project that you previously built with the Red Hat Enterprise Linux version of the GNU Compiler Collection make sure that you discard all previous build results To do so open the project in Eclipse and select Project Clean from the menu 2 2 2 Using the Red Hat Enterprise Linux Toolchain To use the Red Hat Developer Toolset version of Eclipse with support for the toolchain distributed with Red Hat Enterprise Linux either uninstall devtoolset 2 gcc devtoolset 2 binutils and related packages from your system or change the configuration of the project to use absolute paths to the Red Hat Enterprise Linux system versions of gcc g and as To uninstall the Red Hat Developer Tools
167. tionally and another thread accessing it nontransactionally at potentially the same time Note that the data can be safely reclaimed using code like this assuming only one thread ever does this transaction atomic data public false destruct data Here destruct does not race with potential concurrent uses of the data because after the transaction finishes itis guaranteed that data public is false and thus data is private See the specification and the C 11 memory model for more background information about this Note that even if transactions are required to virtually execute in a total order this does not mean that they execute mutually exclusive in time Transactional memory implementations attempt to run transactions as much in parallel as possible to provide scalable performance There are two variants of transactions atomic transactions transaction atomic and relaxed transactions transaction relaxed The former guarantee atomicity with regard to all other code 102 Changes in Version 2 0 but allow only code that is known to not include nontransactional kinds of synchronization such as atomic or volatile memory access In contrast relaxed transactions allow all code for example calls to O functions but only provide atomicity with regard to other transactions Therefore atomic transactions can be nested within other atomic and relaxed transactions but relaxed transactions can only be nested within other relaxed
168. to your 11 2 Using Valgrind To run any of the Valgrind tools on a program you want to profile type the following at a shell prompt scl enable devtoolset 2 valgrind tool tool program argument See Table 11 1 Tools Distributed with Valgrind for Red Hat Developer Toolset for a list of tools that 70 Chapter 11 Valgrind lower case and if this option is omitted Valgrind uses Memcheck by default For example to run Cachegrind on a program to identify the sources of cache misses type scl enable devtoolset 2 valgrind tool cachegrind program argument Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset Valgrind as default scl enable devtoolset 2 bash raumm To verify the version of Valgrind you are using at any point type the following at a shell prompt which valgrind Red Hat Developer Toolset s valgrind executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset Valgrind valgrind version 11 3 Additional Resources A detailed description of Valgrind and its features is beyond the scope of this book For more information see the resources listed below Instal
169. ual Fortran main program and is invoked by the main function which is now generated and put in the same object file as MAIN Note that the libgfortranbegin library is still present for backward compatibility A 2 2 2 4 3 Fortran 2003 Features Improved but still experimental support for polymorphism between libraries and programs and for complicated inheritance patterns Generic interface names which have the same name as derived types are now supported which allows the creation of constructor functions Note that Fortran does not support static constructor functions only default initialization or an explicit structure constructor initialization are available Automatic re allocation In intrinsic assignments to allocatable variables the left hand side will be automatically allocated if unallocated or reallocated if the shape or type parameter is different To avoid the small performance penalty you can use a instead ofa for arrays and character strings or disable the feature using std f95 or fno realloc lhs Experimental support of the ASSOCIATE construct has been added In pointer assignments it is now possible to specify the lower bounds of the pointer and for a rank 1 or a simply contiguous data target to remap the bounds Deferred type parameter For scalar allocatable and pointer variables the character length can now be deferred Namelist variables with allocatable attribute pointer attribute and wit
170. ually need dynamic initialization If the programmer can be sure that no use of the variable in a non defining translation unit needs to trigger dynamic initialization either because the variable is statically initialized or a use of the variable in the defining translation unit will be executed before any uses in another translation unit they can avoid this overhead by using the new fno extern tls init option By default g uses the fextern tls init option C 11 Attribute Syntax g now implements the C 11 attribute syntax for example noreturn void f C 11 Alignment Specifier g now implements the C 11 alignment specifier for example alignas double int i A 2 1 5 Fortran Changes A 2 1 5 1 Caveats The version of module files the mod files has been incremented Fortran modules compiled by earlier GCC versions have to be recompiled when they are used by files compiled with GCC 4 8 as this version of GCC is not able to read mod files created by earlier versions attempting to do so fails with an error 96 Changes in Version 2 0 message rraaum The ABI of the produced assembler data itself has not changed object files and libraries are fully A 2 1 5 2 ABI Compatibility Some internal names used in the assembler or object file have changed for symbols declared in the specification part of a module If an affected module or a file using it via use association is recompi
171. ugger has been adapted to follow GCC s rules on accessing volatile objects when reading or writing target state during expression evaluation A 6 3 Changes Since Red Hat Enterprise Linux 5 9 In addition to the above changes the features below have been added since the release of GDB included in Red Hat Enterprise Linux 5 9 New Features For remote targets debugging of shared libraries is now supported by default New commands set observer and show observer have been added The set observer command accepts on or of f as an argument and can be used to allow or disallow the GNU Debugger to affect the execution of the debugged program Use the show observer command to determine whether observer mode is enabled A new convenience variable thread has been added This variable stores the number of the current thread The source command now accepts s as a valid option This option can be used to search for the Changes in Version 2 0 script in the source search path regardless of the path in the file name Support for tracepoints including fast and static tracepoints has been added to gdbserver The batch command line option has been adapted to disable pagination and queries Direct support for the reading and writing byte word and double word x86 general purpose registers such as al has been added The commands command now accepts a range of breakpoints as an argument The rbreak command now accepts a file name as part of its argu
172. ults in a textual tabular and graphical manner Note that the result sets are updated in a near runtime way which allows the user to use this plug in for longer running monitoring tasks New kernel perf tool integration has been added This plug in uses the performance counters subsystem of the Linux kernel to profile applications makes it easier to analyze the results by hyperlinking to the sources in the workspace projects simplifies the perf tool configuration by selecting the counters to be used and allows the user to run this tool remotely A unified profiling launcher has been added to provide a single method to launch profiling It allows the user to select a profiling category Memory Timing or Coverage and back ends for this category such as OProfile perf or GProf for Timing The C C documentation plug in has been enhanced to recognize and use gtk doc generated documentation and to display it in the Eclipse Help Center The OProfile plug in has been enhanced to support root privilege authentication through polkit This feature is configured automatically The Valgrind plug in now supports the Helgrind tool which can be used to detect synchronization problems such as race conditions deadlocks caused by incorrect locking order or misuse of the POSIX pthreads API When a problem is detected the plug in displays error markers on the corresponding lines in the source code A 2 Changes in GCC Red Hat Developer Toolset 2 0 is
173. ument dependent lookup ADL now directs function search to the namespaces of its arguments regardless of whether the namespace has been imported In addition to member operators the GNU Debugger can now look up operators that are defined in the global scope defined in a namespace and imported via the using directive implicitly imported from an anonymous namespace or the argument dependent lookup ADL operators Support for printing of static const class members that are initialized in the class definition has been enhanced Support for importing of namespaces has been added The C expression parser has been adapted to handle the cast operators static_cast lt gt dynamic_cast lt gt const_cast lt gt and reinterpret_cast lt gt The following changes have been made to the Python scripting support since the release of the GNU Debugger in Red Hat Enterprise Linux 5 8 E N U The GNU Debugger is now installed with a new directory located at opt rh devtoolset 2 root usr share gdb python This directory serves as a standard location for Python scripts written for GDB The Python API has been adapted to provide access to symbols symbol tables program spaces breakpoints inferiors threads and frame s code blocks Users are now also allowed to create custom GDB parameters from the API and manipulate them by using the set and show commands New functions gdb target_charset gdb target wide charset gdb progspaces gdb c
174. upport for a defined set of escape sequences that can be used to display various information The show extended prompt command can be used to determine whether the extended prompt is enabled New set basenames may differ and show basenames may differ commands have been added The set basenames may differ command enables support for source files with multiple base names The show basenames may differ command can be used to determine whether this support is enabled The default option is off to allow faster GDB operations A new command line option ix or init command has been added This option acts like x or command but is executed before loading the debugged program A new command line option iex or init eval command has been added This option acts like ex or eval command but is executed before loading the debugged program The info os command has been changed and can now display information on several objects managed by the operating system in particular The info os procgroups command lists process groups The info os files command lists file descriptors The info os sockets command lists internet domain sockets The info os shm command lists shared memory regions The info os semaphores command lists semaphores The info os msg command lists message queues The info os modules command lists loaded kernel modules GDB now has support for Static Defined Tracing SDT probes Currently the only implemented back end
175. urrent_progspace and gdb string_to_argv have been added A new exception gdb GdbError has been added Changes in Version 2 0 The GNU Debugger now searches pretty printers in the current program space The GNU Debugger can now enable or disable pretty printers individually The GNU Debugger has been adapted to look for names of Python scripts to automatically load ina special section named debug_gdb_scripts A 7 Changes in strace Red Hat Developer Toolset 2 0 is distributed with strace 4 7 which provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version Below is a comprehensive list of new features in this release A 7 1 Changes Since Red Hat Enterprise Linux 6 4 and 5 9 The following features have been added since the release of strace in Red Hat Enterprise Linux 6 4 and 5 9 A new command line option y has been added This option can be used to print file descriptor paths A new command line option P has been added This option can be used to filter system calls based on the file descriptor paths A new command line option I has been added This option can be used to control how interactive strace is A new command line utility Strace Log merge has been added This utility can be used to merge timestamped strace output into a single file The strace utility now uses optimized interfaces to extract data from the traced process for better performance The strace
176. ution of the C standard s core issue 253 Default initialization is allowed if it initializes all subobjects and code that fails to compile can be fixed by providing an initializer such as struct A A struct B A int al const B b B Access control is now applied to typedef names used in a template which may cause G to reject some ill formed code that was accepted by earlier releases The fno access control option can be used as a temporary workaround until the code is corrected G now implements the C standard s core issue 176 Previously G did not support using the injected class name of a template base class as a type name and lookup of the name found the declaration of the template in the enclosing scope Now lookup of the name finds the injected class name which can be used either as a type or as a template depending on whether or not the name is followed by a template argument list As a result of this change some code that was previously accepted may be ill formed because 1 the injected class name is not accessible because it is from a private base or 2 the injected class name cannot be used as an argument for a template parameter In either of these cases the code can be fixed by adding a nested name specifier to explicitly name the template The first can be worked around with fno access control the second is only rejected with pedantic A 2 2 2 3 CIC Warnings GCC 4 7 0 and later adds a
177. veloper Toolset see Red Hat Developer Toolset documentation DRD Revision History dwp dwz Dyninst documentation Additional Resources Eclipse elfedit features New Features elfutils documentation Additional Resources 139 Red Hat Developer Toolset 2 x User Guide eu ar eu findtextrel overview elfutils eu make debug archive overview elfutils eu nm eu objdump overview elfutils eu ranlib overview elfutils eu size 140 Revision History overview elfutils eu strings overview elfutils feedback g see GNU Compiler Collection GAS see GNU assembler GCC see GNU Compiler Collection gcc see GNU Compiler Collection GDB see GNU Debugger gfortran see GNU Compiler Collection Global Support Services GNU assembler documentation Additional Resources 141 Red Hat Developer Toolset 2 x User Guide GNU Binutils see binutils GNU Compiler Collection GNU Debugger documentation Additional Resources GNU linker documentation Additional Resources gprof features New Features GSS see Global Support Services Helgrind help 142 Id see GNU linker linking see GNU linker Massif nm overview binutils objcopy features New Features objdump features New Features opannotate Revision History 143 Red Hat Developer Toolset 2 x User Guide opgprof ophelp opimport OProfile
178. x highlighting as follows Red Hat Developer Toolset 2 x User Guide occ ere NA TERE IE MNT NW static int kvm vm ioctl deassign device struct kvm kvm struct kvm assigned pci dev assigned dev int r 0 struct kvm_assigned_dev_kernel match mutex_lock amp kvm gt lock match kvm_find_assigned_dev amp kvm gt arch assigned_dev_head assigned_dev gt assigned_dev_id if match printk KERN_INFO s device hasn t been assigned before so cannot be deassigned n __func__ r EINVAL goto out kvm_deassign_device kvm match kvm_free_assigned_device kvm match out mutex_unlock amp kvm gt lock return r e NM d 1 3 Notes and Warnings Finally we use three visual styles to draw attention to information that might otherwise be overlooked Notes are tips shortcuts or alternative approaches to the task at hand Ignoring a note should have no negative consequences but you might miss out on a trick that makes your life easier Important boxes detail things that are easily missed configuration changes that only apply to the current session or services that need restarting before an update will apply Ignoring a box labeled Important will not cause data loss but may cause irritation and frustration AD Warning _____ Warnings should not be ignored Ignoring warnings will most likely cause data loss 2 Getting Help and Giving Feedback 2 1 Do You Need Help If
179. xtension To link object files together and create a binary file run scl enable devtoolset 2 g o output file object file Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset g as default scl enable devtoolset 2 bash 32 Chapter 3 GNU Compiler Collection GCC rraa To verify the version of g you are using at any point type the following at a shell prompt N which g Red Hat Developer Toolset s g executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset g 48 ES g v Li E important Some newer library features are statically linked into applications built with Red Hat Developer Toolset to support execution on multiple versions of Red Hat Enterprise Linux This adds a small additional security risk as normal Red Hat Enterprise Linux errata would not change this code If the need for developers to rebuild their applications due to such an issue arises Red Hat will signal this via a security erratum Developers are strongly advised not to statically link their entire application for the same reasons Example 3 3 Compiling a C
180. you experience difficulty with a procedure described in this documentation visit the Red Hat Customer 10 Preface search or browse through a knowledgebase of technical support articles about Red Hat products submit a support case to Red Hat Global Support Services GSS access other product documentation Red Hat also hosts a large number of electronic mailing lists for discussion of Red Hat software and Click on the name of any mailing list to subscribe to that list or to access the list archives 2 2 We Need Feedback If you find a typographical error in this manual or if you have thought of a way to make this manual against the product Red Hat Developer Toolset When submitting a bug report be sure to mention the manual s identifier doc User Guide If you have a suggestion for improving the documentation try to be as specific as possible when describing it If you have found an error please include the section number and some of the surrounding text so we can find it easily 11 12 Red Hat Developer Toolset 2 x User Guide Part I Introduction Chapter 1 Red Hat Developer Toolset Chapter 1 Red Hat Developer Toolset 1 1 About Red Hat Developer Toolset Red Hat Developer Toolset is a Red Hat offering for developers on the Red Hat Enterprise Linux platform and provides a complete set of development and performance analysis tools that can be installed and used on multiple versions of Red Hat Enterprise Linux Execut

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