[LLVMdev] potential mach_override/mach_override.c fix

[Alexander Potapenko]

Hi Jack,
Thank you, I've landed this to LLVM (r168032)

On Thu, Nov 15, 2012 at 6:18 AM, Jack Howarth <howarth at bromo.med.uc.edu> wrote:
>    In testing build patches for gcc 4.8 to allow darwin to have asan support,
> I ran across a defect in mach_override/mach_override.c...
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55289#c27
>
> which was solved with the patch proposed by Alexander Potapenko in...
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55289#c29
>
> Index: mach_override.c
> ===================================================================
> --- mach_override.c    (revision 167724)
> +++ mach_override.c    (working copy)
> @@ -725,6 +725,8 @@
>          { 0x2, {0xFF, 0x00}, {0x89, 0x00} },                               //
> mov r/m32,r32 or r/m16,r16
>          { 0x3, {0xFF, 0xFF, 0xFF}, {0x49, 0x89, 0xF8} },                   //
> mov %rdi,%r8
>          { 0x4, {0xFF, 0xFF, 0xFF, 0xFF}, {0x40, 0x0F, 0xBE, 0xCE} },       //
> movsbl %sil,%ecx
> +        { 0x7, {0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00},
> +               {0x48, 0x8D, 0x05, 0x00, 0x00, 0x00, 0x00} },  // lea
> $imm(%rip),%rax
>          { 0x3, {0xFF, 0xFF, 0xFF}, {0x0F, 0xBE, 0xCE} },  // movsbl, %dh, %ecx
>          { 0x3, {0xFF, 0xFF, 0x00}, {0xFF, 0x77, 0x00} },  // pushq $imm(%rdi)
>          { 0x2, {0xFF, 0xFF}, {0xDB, 0xE3} }, // fninit
>
> which produced a usable libsanitizer on x86_64 and i386 darwin. Perhaps these
> instances of lea aren't a problem on llvm, but I thought I ought to point this
> fix out as a potential change for the llvm 3.2 release.
>                 Jack
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-- 
Alexander Potapenko
Software Engineer
Google Moscow