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| author | Tobias Burnus <burnus@net-b.de> | 2014-03-24 20:53:52 +0100 |
|---|---|---|
| committer | Tobias Burnus <burnus@gcc.gnu.org> | 2014-03-24 20:53:52 +0100 |
| commit | 09f15d1b52b9e1e37dc02c8674c8738a1b036ea7 (patch) | |
| tree | 8d3b75c7f580fdd02d924c5a0f27b9915d8b8bab | |
| parent | 6f6c00f3a3e5f79e89c4ec8a4901ac270d451023 (diff) | |
| download | gcc-09f15d1b52b9e1e37dc02c8674c8738a1b036ea7.zip gcc-09f15d1b52b9e1e37dc02c8674c8738a1b036ea7.tar.gz gcc-09f15d1b52b9e1e37dc02c8674c8738a1b036ea7.tar.bz2 | |
invoke.texi (-flto): Expand section about using static libraries with LTO.
2014-03-24 Tobias Burnus <burnus@net-b.de>
* doc/invoke.texi (-flto): Expand section about
using static libraries with LTO.
From-SVN: r208798
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/doc/invoke.texi | 13 |
2 files changed, 15 insertions, 3 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index d904fc0..3741b54 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2014-03-24 Tobias Burnus <burnus@net-b.de> + + * doc/invoke.texi (-flto): Expand section about + using static libraries with LTO. + 2014-03-24 Andreas Krebbel <Andreas.Krebbel@de.ibm.com> PR rtl-optimization/60501 diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 4c183a3..78ddde0 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -8664,8 +8664,13 @@ regular (non-LTO) compilation. If object files containing GIMPLE bytecode are stored in a library archive, say @file{libfoo.a}, it is possible to extract and use them in an LTO link if you -are using a linker with plugin support. To enable this feature, use -the flag @option{-fuse-linker-plugin} at link time: +are using a linker with plugin support. To create static libraries suitable +for LTO, use @command{gcc-ar} and @command{gcc-ranlib} instead of @command{ar} +and @code{ranlib}; to show the symbols of object files with GIMPLE bytecode, use +@command{gcc-nm}. Those commands require that @command{ar}, @command{ranlib} +and @command{nm} have been compiled with plugin support. At link time, use the the +flag @option{-fuse-linker-plugin} to ensure that the library participates in +the LTO optimization process: @smallexample gcc -o myprog -O2 -flto -fuse-linker-plugin a.o b.o -lfoo @@ -8678,7 +8683,9 @@ to make them part of the aggregated GIMPLE image to be optimized. If you are not using a linker with plugin support and/or do not enable the linker plugin, then the objects inside @file{libfoo.a} are extracted and linked as usual, but they do not participate -in the LTO optimization process. +in the LTO optimization process. In order to make a static library suitable +for both LTO optimization and usual linkage, compile its object files with +@option{-flto} @code{-ffat-lto-objects}. Link-time optimizations do not require the presence of the whole program to operate. If the program does not require any symbols to be exported, it is |