On Thu, Mar 10, 2016 at 07:57:53PM +0100, Hendrik Leppkes wrote: > 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).
as i was the one applying it IIRC, i should probably comment ... iam not against this being partially or fully revered/mode conditional if it causes more problems than it does good. > > 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 -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB When the tyrant has disposed of foreign enemies by conquest or treaty, and there is nothing more to fear from them, then he is always stirring up some war or other, in order that the people may require a leader. -- Plato
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