----- Am 13. Okt 2017 um 16:02 schrieb David Edelsohn dje....@gmail.com: > On Fri, Oct 13, 2017 at 3:06 AM, Sebastian Huber > <sebastian.hu...@embedded-brains.de> wrote: >> Hello, >> >> I would like to update the documentation of these compiler flags and have >> some questions. The -ffunction-sections and -fdata-sections documentation >> is currently: >> >> "Place each function or data item into its own section in the output file if >> the target supports arbitrary sections. The name of the function or the name >> of the data item determines the section’s name in the output file. >> >> Use these options on systems where the linker can perform optimizations to >> improve locality of reference in the instruction space. Most systems using >> the ELF object format and SPARC processors running Solaris 2 have linkers >> with such optimizations. AIX may have these optimizations in the future. >> >> Only use these options when there are significant benefits from doing so. >> When you specify these options, the assembler and linker create larger >> object and executable files and are also slower. You cannot use |gprof| on >> all systems if you specify this option, and you may have problems with >> debugging if you specify both this option and -g." >> >> The end-of-life of Solaris 2.6 was 2006. Is it worth to mention this here? >> >> This "AIX may have these optimizations in the future." is there since at >> least 1996. What is the current AIX status? >> >> Is the "Only use these options when there are significant benefits from >> doing so. When you specify these options, the assembler and linker create >> larger object and executable files and are also slower. You cannot use >> |gprof| on all systems if you specify this option, and you may have problems >> with debugging if you specify both this option and -g." still correct on the >> systems of today? >> >> Do these options affect the code generation? > > Out of date documentation in GCC? What a surprise! > > -ffunction-sections and -fdata-sections are available on AIX. The AIX > linker rearranges sections (CSECTs) based on the call graph. The > performance impact varies. > > I'm not certain what the central question of the email message is.
The central question for me is the effect on code generation.
