[all-commits] [llvm/llvm-project] 13fdde: [BPF] Emit proper error message for insns with tie...

[yonghong-song via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 13fddeaf2c494e2f88ef4e7063ae2ee3278e4f1e
      https://github.com/llvm/llvm-project/commit/13fddeaf2c494e2f88ef4e7063ae2ee3278e4f1e
  Author: yonghong-song <yhs at fb.com>
  Date:   2025-07-02 (Wed, 02 Jul 2025)

  Changed paths:
    M llvm/lib/Target/BPF/AsmParser/BPFAsmParser.cpp
    A llvm/test/MC/BPF/bad-tied.s

  Log Message:
  -----------
  [BPF] Emit proper error message for insns with tied operands (#146778)

Jonathan Cottrill reported a crash in [1] with the following command
line:
```
  $ echo 'r0 = atomic_fetch_add((u64*)(r2 + 0), r1)' | llvm-mc --arch bpf --filetype null
```

Note that in the above command, the insn specification requires that r0
and r1 must be the same register. Otherwise, the crash will happen.

Let us add a case Match_InvalidTiedOperand to handle such invalid insns.
With this patch, the error message looks like below:
```
  <stdin>:1:39: error: operand is not the same as the dst register
  r0 = atomic_fetch_add((u64*)(r2 + 0), r1)
                                        ^
```
The error message is much better than the crash. Some other insns are
also covered by this patch.
```
  $ echo 'w0 = xchg32_32(r2 + 0, w1)' | llvm-mc --arch bpf --filetype null
  <stdin>:1:24: error: operand is not the same as the dst register
  w0 = xchg32_32(r2 + 0, w1)
                         ^
```
  [1] https://github.com/llvm/llvm-project/issues/145180

Co-authored-by: Yonghong Song <yonghong.song at linux.dev>



To unsubscribe from these emails, change your notification settings at https://github.com/llvm/llvm-project/settings/notifications