[all-commits] [llvm/llvm-project] 32d535: BPF: Emit an error for illegal LD_imm64 insn when ...

[yonghong-song via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 32d535195ec5d9b0caf03fee13f796fc8c66a79f
      https://github.com/llvm/llvm-project/commit/32d535195ec5d9b0caf03fee13f796fc8c66a79f
  Author: yonghong-song <yhs at fb.com>
  Date:   2023-12-07 (Thu, 07 Dec 2023)

  Changed paths:
    M llvm/lib/Target/BPF/MCTargetDesc/BPFInstPrinter.cpp

  Log Message:
  -----------
  BPF: Emit an error for illegal LD_imm64 insn when LLVM_ENABLE_ASSERTI… (#74035)

…ONS=OFF

Jose reported an issue ([1]) where for the below illegal asm code
```
  r0 = 1 + w3 ll
```
clang actually supports it and generates the object code.

Further investigation finds that clang actually intends to reject the
above code as well but only when the clang is built with
LLVM_ENABLE_ASSERTIONS=ON.

I later found that clang16 (built by redhat and centos) in fedora system
has the same issue since they also have LLVM_ENABLE_ASSERTIONS=OFF
([2]).

So let BPF backend report an error for the above case regardless of the
LLVM_ENABLE_ASSERTIONS setting.

  [1] https://lore.kernel.org/bpf/87leahx2xh.fsf@oracle.com/#t
[2]
https://lore.kernel.org/bpf/840e33ec-ea4c-4b55-bda1-0be8d1e0324f@linux.dev/

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