From f381d87aa5928ecdfe531b2c8706843f65c951b9 Mon Sep 17 00:00:00 2001 From: Sebastian Huber Date: Wed, 18 Oct 2017 07:36:38 +0000 Subject: [PATCH] Update -ffunction/data-sections documentation gcc/ * doc/invoke.texi (ffunction-sections and fdata-sections): Update. From-SVN: r253842 --- gcc/ChangeLog | 5 +++++ gcc/doc/invoke.texi | 32 ++++++++++++++++++++------------ 2 files changed, 25 insertions(+), 12 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index c8a4680..a59161d 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2017-10-18 Sebastian Huber + + * doc/invoke.texi (ffunction-sections and fdata-sections): + Update. + 2017-10-17 Eric Botcazou * tree-ssa-loop-ivopts.c (add_autoinc_candidates): Bail out only if diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 6518ac0..5e88279 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -9712,18 +9712,26 @@ 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 @command{gprof} on all systems if you -specify this option, and you may have problems with debugging if -you specify both this option and @option{-g}. +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 have linkers with such optimizations. On AIX, the linker +rearranges sections (CSECTs) based on the call graph. The performance impact +varies. + +Together with a linker garbage collection (linker @option{--gc-sections} +option) these options may lead to smaller statically-linked executables (after +stripping). + +On ELF/DWARF systems these options do not degenerate the quality of the debug +information. There could be issues with other object files/debug info formats. + +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. These options affect code generation. +They prevent optimizations by the compiler and assembler using relative +locations inside a translation unit since the locations are unknown until +link time. An example of such an optimization is relaxing calls to short call +instructions. @item -fbranch-target-load-optimize @opindex fbranch-target-load-optimize -- 2.7.4