On Thu, Nov 01, 2018 at 12:26:34PM -0700, Ian Romanick wrote: > On 10/31/2018 09:08 PM, Jonathan Gray wrote: > > Make similiar changes to libglvnd to avoid a text relocation in > > x86 tsd stubs fixing the build with lld. > > > > Signed-off-by: Jonathan Gray <j...@jsg.id.au> > > Cc: mesa-sta...@lists.freedesktop.org > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108541 > > --- > > src/mapi/entry_x86_tsd.h | 14 +++++++++----- > > 1 file changed, 9 insertions(+), 5 deletions(-) > > > > diff --git a/src/mapi/entry_x86_tsd.h b/src/mapi/entry_x86_tsd.h > > index 0c28c8ff068..e08a02f3db2 100644 > > --- a/src/mapi/entry_x86_tsd.h > > +++ b/src/mapi/entry_x86_tsd.h > > @@ -31,7 +31,7 @@ > > #define HIDDEN > > #endif > > > > -#define X86_ENTRY_SIZE 32 > > +#define X86_ENTRY_SIZE 64 > > > > __asm__(".text\n" > > ".balign 32\n" > > @@ -44,12 +44,16 @@ __asm__(".text\n" > > func ":" > > > > #define STUB_ASM_CODE(slot) \ > > - "movl " ENTRY_CURRENT_TABLE ", %eax\n\t" \ > > + "call 1f\n\t" \ > > + "1:\n\t" \ > > + "popl %eax\n\t" \ > > + "addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %eax\n\t" \ > > + "movl " ENTRY_CURRENT_TABLE "@GOT(%eax), %eax\n\t" \ > > + "mov (%eax), %eax\n\t" \ > > "testl %eax, %eax\n\t" \ > > - "je 1f\n\t" \ > > - "jmp *(4 * " slot ")(%eax)\n" \ > > + "jne 1f\n\t" \ > > + "call " ENTRY_CURRENT_TABLE_GET "@PLT\n\t" \ > > "1:\n\t" \ > > - "call " ENTRY_CURRENT_TABLE_GET "\n\t" \ > > "jmp *(4 * " slot ")(%eax)" > > After this change, the code is: > > #define STUB_ASM_CODE(slot) \ > "call 1f\n\t" \ > "1:\n\t" \ > "popl %eax\n\t" \ > "addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %eax\n\t" \ > "movl " ENTRY_CURRENT_TABLE "@GOT(%eax), %eax\n\t" \ > "mov (%eax), %eax\n\t" \ > "testl %eax, %eax\n\t" \ > "jne 1f\n\t" \ > "call " ENTRY_CURRENT_TABLE_GET "@PLT\n\t" \ > "1:\n\t" \ > "jmp *(4 * " slot ")(%eax)" > > So there's going to be two labels "1:". Does that even assemble?
Yes, the call/jmp is always forward as it is '1f'. This also runs glxinfo, glxgears etc on a pentium m running OpenBSD/i386. https://github.com/NVIDIA/libglvnd/blob/master/src/GLdispatch/vnd-glapi/entry_x86_tsd.c#L58 libglvnd has two labels like this as well, the ebx use there isn't needed. _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev