gcc: Build libgcc with BR2_TARGET_OPTIMIZATION flags
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Message ID 20180116190211.24901-1-abrodkin@synopsys.com
State Superseded
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  • gcc: Build libgcc with BR2_TARGET_OPTIMIZATION flags
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Commit Message

Alexey Brodkin Jan. 16, 2018, 7:02 p.m. UTC
libgcc gets built very early and what's more it is built not by
"normal" cross gcc later found in "output/host/usr/bin" but by
gcc's own bare-minimal version: output/build/host-gcc-xxx/build/./gcc/xgcc.

Which in the end means BR2_TARGET_OPTIMIZATION is not applied to
cross-compiler via toolchain wrapper.

But given libgcc is an essential target executable we may want it to
be built with the same "optimization" flags as all other libs and binaries.

Technically this is doable with TARGET_ABI which is added to TARGET_CFLAGS
but user cannot [or at least is not supposed to] modify TARGET_ABI as it
is used for tunign for a particular platform.

But still there might be a need to compile everything for tha target with
a special compiler option and this change allows for that.

For eaxmple ARC still doesn't have properly working link-time relaxation
which requires us to compile everything properly from the beginning, otherwise
we may face a situation when huge apps/libs like Qt5WebKit might fail to pass
the final linkage because some symbols might be too far from each other as
by default gcc will try to use shorter relocations. Solution is as simple as
rebuild of everything with "-mlong-calls" so that all the symbols are
compiled with full 32-bit relocations. And now only libgcc causes problems
because it contains quite a few symbols used widely by other binaries like
millicode, some math stuff etc.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
 package/gcc/gcc.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff mbox series

diff --git a/package/gcc/gcc.mk b/package/gcc/gcc.mk
index 27fc1e987c..afe59986fe 100644
--- a/package/gcc/gcc.mk
+++ b/package/gcc/gcc.mk
@@ -109,7 +109,7 @@  HOST_GCC_COMMON_CONF_OPTS = \
 # Propagate options used for target software building to GCC target libs