| Message ID | 20240408131600.81682-2-jdek@itanimul.li |
|---|---|
| State | New |
| Headers | show |
| Series | [FFmpeg-devel,v2,1/2] configure,etc: unify shebang usage | expand |
| Context | Check | Description |
|---|---|---|
| yinshiyou/make_loongarch64 | success | Make finished |
| yinshiyou/make_fate_loongarch64 | success | Make fate finished |
| andriy/make_x86 | success | Make finished |
| andriy/make_fate_x86 | success | Make fate finished |
On Mon, 8 Apr 2024, J. Dekker wrote: > The preferred way to use LTO is --enable-lto but often times packagers > still end up with -flto in cflags for various reasons. Using grep > on binary object files is brittle and relies on specific object > representation, which in the case of LLVM bitcode, debug-info or other > intermediary formats can fail silently. > > This patch changes the check to a more commonly used define for > big-endian systems. It's not common only for big-endian systems, but for GCC-style compilers on all endians. > More checks may need to be added in the future to cover legacy machines. Don't use the word "legacy" here. This define is not standard, so it's perfectly plausible to have a modern, standards compliant compiler that just doesn't use this define. With the commmit message you added here, the change is ok, but please do reword the last sentence above. I'd suggest changing the last paragraph into this: --- This patch changes the check to a more commonly used define for GCC style compilers. More checks may be needed to cover other potential compilers that don't use the __BYTE_ORDER__ define. --- // Martin
diff --git a/configure b/configure index 7b6f48e631..e787f13e0b 100755 --- a/configure +++ b/configure @@ -6120,11 +6120,7 @@ extern_prefix=${sym%%ff_extern*} check_cc pragma_deprecated "" '_Pragma("GCC diagnostic push") _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")' -# The global variable ensures the bits appear unchanged in the object file. -test_cc <<EOF || die "endian test failed" -unsigned int endian = 'B' << 24 | 'I' << 16 | 'G' << 8 | 'E'; -EOF -od -t x1 $TMPO | grep -q '42 *49 *47 *45' && enable bigendian +test_cpp_condition stdlib.h "defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)" && enable bigendian check_cc const_nan math.h "struct { double d; } static const bar[] = { { NAN } }"
The preferred way to use LTO is --enable-lto but often times packagers still end up with -flto in cflags for various reasons. Using grep on binary object files is brittle and relies on specific object representation, which in the case of LLVM bitcode, debug-info or other intermediary formats can fail silently. This patch changes the check to a more commonly used define for big-endian systems. More checks may need to be added in the future to cover legacy machines. Signed-off-by: J. Dekker <jdek@itanimul.li> --- configure | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)