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[AArch64] Error when assembling call to function named ror #79729

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zyedidia opened this issue Jan 28, 2024 · 2 comments · Fixed by #80571
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[AArch64] Error when assembling call to function named ror #79729

zyedidia opened this issue Jan 28, 2024 · 2 comments · Fixed by #80571
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@MaskRay
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backend:AArch64

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@zyedidia
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zyedidia commented Jan 28, 2024 •
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The following AArch64 assembly file fails to compile with Clang even though it is valid:

ror:
    ret

foo:
    bl ror

$ clang -c test.s
test.s:5:11: error: expected #imm after shift specifier
    bl ror
          ^
$ gcc -c test.s
$ # no error

ror or any other aarch64 shift operation should be a valid function/label name. Tested with the latest version of LLVM.
@pinskia
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pinskia commented Jan 28, 2024

You can also reproduce it with a C testcase with just -c -save-temps too:

int ror(void);
int f()
{
        return ror();
}

@llvmbot
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llvmbot commented Jan 28, 2024

@llvm/issue-subscribers-backend-aarch64

Author: Zachary Yedidia (zyedidia)

The following AArch64 assembly file fails to compile with Clang even though it is valid: 
ror:
    ret

foo:
    bl ror

$ clang -c test.s
test.s:5:11: error: expected #imm after shift specifier
    bl ror
          ^
$ gcc -c test.s
$ # no error

ror or any other aarch64 shift operation should be a valid function/label name. Tested with the latest version of LLVM.

@MaskRay MaskRay self-assigned this Feb 3, 2024
@MaskRay MaskRay mentioned this issue Feb 4, 2024
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MaskRay added a commit that referenced this issue Feb 12, 2024
@MaskRay
[AArch64AsmParser] Allow branch target symbol to have a shift/extend …
5da8013 
…modifier name (#80571)

Shift and extend modifiers are parsed as separate operands. When a
symbol operand of a branch instruction has such a "bad" name,
AArch64AsmParser will report an error.

```
% cat a.c
void lsl(); void lsr(); void asr(); void ror(); void uxtb(); void sxtx();
void foo() { lsl(); asr(); asr(); ror(); uxtb(); sxtx(); }
% clang --target=aarch64 -c -save-temps a.c
a.s:15:8: error: expected #imm after shift specifier
        bl      lsl
                   ^
a.s:16:8: error: expected #imm after shift specifier
        bl      asr
                   ^
a.s:17:8: error: expected #imm after shift specifier
        bl      asr
                   ^
a.s:18:8: error: expected #imm after shift specifier
        bl      ror
                   ^
a.s:19:5: error: expected label or encodable integer pc offset
        bl      uxtb
                ^
a.s:20:5: error: expected label or encodable integer pc offset
        bl      sxtx
                ^
```

In contrast, gas correctly parses these instructions.

Fix #79729 by parsing shift/extend modifier after an immediate
value/register
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[AArch64AsmParser] Allow branch target symbol to have a shift/extend modifier name llvm/llvm-project
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@MaskRay @zyedidia @pinskia @EugeneZelenko @llvmbot