ffmpeg | branch: master | Martin Storsjö <mar...@martin.st> | Tue Mar 13 00:13:55 2018 +0200| [847190ebd99ffd57dc89bd568a33bf2d5c424129] | committer: Martin Storsjö
configure: Don't assume an aligned stack on clang on windows If we'd enable a 16 byte aligned stack, clang/llvm would also assume that alignment everywhere and produce code that strictly requires it. That would require adding realignment (via attribute_align_arg) on every single public library function or enable -mstackrealign (which does the same on every single function). Also relatedly; the parameter currently tested (-mllvm -stack-alignment=16) hasn't actually been supported for quite some time; current clang versions use -mstack-alignment=16 for the same. Actually testing for that parameter would be a different change though, since it has a real risk of changing behaviour on any other platform where clang is used. Signed-off-by: Martin Storsjö <mar...@martin.st> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=847190ebd99ffd57dc89bd568a33bf2d5c424129 --- configure | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/configure b/configure index 42465edf94..95e6006440 100755 --- a/configure +++ b/configure @@ -4960,7 +4960,16 @@ elif enabled gcc; then elif enabled llvm_gcc; then check_cflags -mllvm -stack-alignment=16 elif enabled clang; then - check_cflags -mllvm -stack-alignment=16 + if [ "$target_os" = "mingw32" -o "$target_os" = "win32" ] && enabled x86_32; then + # Clang doesn't support maintaining alignment without assuming the + # same alignment in every function. If 16 byte alignment would be + # enabled, one would also have to either add attribute_align_arg on + # every single entry point into the libraries or enable -mstackrealign + # (doing stack realignment in every single function). + disable aligned_stack + else + check_cflags -mllvm -stack-alignment=16 + fi check_cflags -Qunused-arguments check_cflags -Werror=implicit-function-declaration check_cflags -Werror=missing-prototypes _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog
