[all-commits] [llvm/llvm-project] df277e: [X86][MC] Fix the bug of -output-asm-variant=1 for...

KanRobert via All-commits all-commits at lists.llvm.org
Thu Feb 16 17:54:09 PST 2023


  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: df277ec67efd1bec3aa2fa8b02d84db0ea8b2f1c
      https://github.com/llvm/llvm-project/commit/df277ec67efd1bec3aa2fa8b02d84db0ea8b2f1c
  Author: Shengchen Kan <shengchen.kan at intel.com>
  Date:   2023-02-17 (Fri, 17 Feb 2023)

  Changed paths:
    M llvm/lib/Target/X86/MCTargetDesc/X86IntelInstPrinter.cpp
    M llvm/test/MC/Disassembler/X86/intel-syntax.txt

  Log Message:
  -----------
  [X86][MC] Fix the bug of -output-asm-variant=1 for intel syntax

Before this patch

```
$ echo "leal    (,%r15), %eax" | llvm-mc --show-encoding --output-asm-variant=1

        lea     eax, [r15]                      # encoding: [0x42,0x8d,0x04,0x3d,0x00,0x00,0x00,0x00]

$ echo "lea     eax, [r15]" | llvm-mc --show-encoding -x86-asm-syntax=intel --output-asm-variant=1

        lea     eax, [r15]                      # encoding: [0x41,0x8d,0x07]
```

MC printed the register r15 as a base in intel syntax even when it's an index.
Then we got a different encoding by using the assembly from the output of the
first command.

I believe the behavior is too weird to be called a feature.

After this patch, we get

```
$ echo "leal    (,%r15), %eax" | llvm-mc --show-encoding --output-asm-variant=1

        lea     eax, [1*r15]                    # encoding: [0x42,0x8d,0x04,0x3d,0x00,0x00,0x00,0x00]
```

Reviewed By: RKSimon, pengfei, MaskRay

Differential Revision: https://reviews.llvm.org/D144183




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