[llvm] 3367e9d - [X86] Enable multibyte NOPs in 64-bit mode for padding/alignment.

Wed Jul 1 15:14:59 PDT 2020

This commit seems to be causing the LLD COFF/lto.ll test to fail:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/43382/steps/check-lld%20ubsan/logs/stdio

Could you please take a look?

/b/sanitizer-x86_64-linux-fast/build/llvm-project/lld/test/COFF/lto.ll:91:17:
error: TEXT-10-NEXT: expected string not found in input; TEXT-10-NEXT:
nop
                ^
<stdin>:10:30: note: scanning from here
14000100b: 0f 1f 44 00 00 nopl (%rax,%rax)
                             ^
<stdin>:12:16: note: possible intended match here
140001011: cc int3
               ^

Input file: <stdin>
Check file: /b/sanitizer-x86_64-linux-fast/build/llvm-project/lld/test/COFF/lto.ll

-dump-input=help describes the format of the following dump.

Full input was:
<<<<<<
           1:
           2: /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/tools/lld/test/COFF/Output/main.exe:
file format coff-x86-64
           3:
           4:
           5: Disassembly of section .text:
           6:
           7: 0000000140001000 <.text>:
           8: 140001000: c3 retq
           9: 140001001: 66 2e 0f 1f 84 00 00 00 00 00 nopw %cs:(%rax,%rax)
          10: 14000100b: 0f 1f 44 00 00 nopl (%rax,%rax)
next:91'0                                  X~~~~~~~~~~~~ error: no match found
          11: 140001010: c3 retq
next:91'0     ~~~~~~~~~~~~~~~~~~
          12: 140001011: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
next:91'1                    ?   possible intended match
          13: 140001012: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
          14: 140001013: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
          15: 140001014: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
          16: 140001015: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
          17: 140001016: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
          18: 140001017: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
          19: 140001018: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
          20: 140001019: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
          21: 14000101a: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
          22: 14000101b: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
          23: 14000101c: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
          24: 14000101d: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
          25: 14000101e: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
          26: 14000101f: cc int3
next:91'0     ~~~~~~~~~~~~~~~~~~
          27: 140001020: 48 83 ec 28 subq $40, %rsp
next:91'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          28: 140001024: e8 d7 ff ff ff callq 0x140001000 <.text>
next:91'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          29: 140001029: 31 c0 xorl %eax, %eax
next:91'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          30: 14000102b: 48 83 c4 28 addq $40, %rsp
next:91'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          31: 14000102f: c3 retq
next:91'0     ~~~~~~~~~~~~~~~~~~
>>>>>>

On Wed, Jul 1, 2020 at 10:57 AM Craig Topper via llvm-commits <
llvm-commits at lists.llvm.org> wrote:

>
> Author: Craig Topper
> Date: 2020-07-01T10:57:24-07:00
> New Revision: 3367e9dac56024147bbd916c40bfe6a4ee61079b
>
> URL:
> https://github.com/llvm/llvm-project/commit/3367e9dac56024147bbd916c40bfe6a4ee61079b
> DIFF:
> https://github.com/llvm/llvm-project/commit/3367e9dac56024147bbd916c40bfe6a4ee61079b.diff
>
> LOG: [X86] Enable multibyte NOPs in 64-bit mode for padding/alignment.
>
> The default CPU used by llvm-mc doesn't have the NOPL feature, but
> if we know we're compiling in 64-bit mode we should be able to
> use nopl.
>
> Added:
>
>
> Modified:
>     llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
>     llvm/test/MC/X86/align-branch-bundle.s
>     llvm/test/MC/X86/align-branch-pad-max-prefix.s
>
> Removed:
>
>
>
>
> ################################################################################
> diff  --git a/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
> b/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
> index e49ee1792373..bf3b6bcb5463 100644
> --- a/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
> +++ b/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
> @@ -1096,7 +1096,7 @@ bool X86AsmBackend::writeNopData(raw_ostream &OS,
> uint64_t Count) const {
>
>    // This CPU doesn't support long nops. If needed add more.
>    // FIXME: We could generated something better than plain 0x90.
> -  if (!STI.getFeatureBits()[X86::FeatureNOPL]) {
> +  if (!STI.hasFeature(X86::FeatureNOPL) &&
> !STI.hasFeature(X86::Mode64Bit)) {
>      for (uint64_t i = 0; i < Count; ++i)
>        OS << '\x90';
>      return true;
>
> diff  --git a/llvm/test/MC/X86/align-branch-bundle.s
> b/llvm/test/MC/X86/align-branch-bundle.s
> index 43dabca9e477..a62159943683 100644
> --- a/llvm/test/MC/X86/align-branch-bundle.s
> +++ b/llvm/test/MC/X86/align-branch-bundle.s
> @@ -6,7 +6,6 @@
>  # CHECK-NEXT:       1:       testq    $2, %rdx
>  # CHECK-NEXT:       8:       jne
>  # CHECK-NEXT:       e:       nop
> -# CHECK-NEXT:       f:       nop
>  # CHECK-NEXT:      10:       jle
>
>      .text
>
> diff  --git a/llvm/test/MC/X86/align-branch-pad-max-prefix.s
> b/llvm/test/MC/X86/align-branch-pad-max-prefix.s
> index 6cce49d55d47..9576562667ac 100644
> --- a/llvm/test/MC/X86/align-branch-pad-max-prefix.s
> +++ b/llvm/test/MC/X86/align-branch-pad-max-prefix.s
> @@ -10,9 +10,7 @@
>    # following nops, doing so would make the jmp misaligned.
>  # CHECK:      18:          jmp
>    jmp bar
> -# CHECK:      1d:          nop
> -# CHECK:      1e:          nop
> -# CHECK:      1f:          nop
> +# CHECK:      1d:          nopl (%rax)
>  # CHECK:      20:          int3
>    .p2align 5
>    int3
>
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20200701/03f3cf38/attachment.html>