On Mon, Sep 21, 2015 at 6:41 AM, Alex Smith <alex.sm...@warpsharp.info> wrote: > From: Alex Smith <alex.sm...@warpsharp.info> > > Binutils will always strip the relocation information from executable > files even if it needs it (dynamicbase/ASLR). We can work around this > by using the pic-executable flag combined with setting the correct entry > point since apparently ld forgets what that should be. This problem > affects both 32 and 64-bit mingw-w64. > > We can combine the nxcompat/dynamicbase check because they were added to > binutils at the same time. > > Signed-off-by: Alex Smith <alex.sm...@warpsharp.info> > > Conflicts: > configure > --- > configure | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/configure b/configure > index d2a25bb..d6ab35a 100755 > --- a/configure > +++ b/configure > @@ -4367,8 +4367,6 @@ case $target_os in > LIBTARGET=arm-wince > fi > enabled shared && ! enabled small && check_cmd $windres --version && > enable gnu_windres > - check_ldflags -Wl,--nxcompat > - check_ldflags -Wl,--dynamicbase > enabled x86_32 && check_ldflags -Wl,--large-address-aware > shlibdir_default="$bindir_default" > SLIBPREF="" > @@ -4392,6 +4390,17 @@ case $target_os in > objformat="win32" > ranlib=: > enable dos_paths > + check_ldflags -Wl,--nxcompat,--dynamicbase > + # Lets work around some stupidity in binutils. > + # ld will strip relocations from executables even though we need them > + # for dynamicbase (ASLR). Using -pie does retain the reloc section > + # however ld then forgets what the entry point should be (oops) so we > + # have to manually (re)set it. > + if enabled x86_32; then > + add_ldexeflags -Wl,--pic-executable,-e,_mainCRTStartup > + elif enabled x86_64; then > + add_ldexeflags -Wl,--pic-executable,-e,mainCRTStartup > + fi > ;; > win32|win64) > disable symver
This patch (the relocations part) broke debugging mingw-w64 ffmpeg builds with gdb, you can't set breakpoints anymore when its applied. It should either be reverted or made dependent on --enable/disable-debug (I would favor the first, honestly, since its a rather ugly hack in itself). Did the binutils/mingw guys ever comment anything useful on this issue? - Hendrik _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
