Unresolved external symbol in X86 inline asm after r314493/r314494

[llvmbot]

Bugzilla Link	35290
Version	unspecified
OS	Windows NT
Blocks	#11360
Reporter	LLVM Bugzilla Contributor
CC	@jrmuizel,@RKSimon,@rnk

Extended Description

I bisected this to r314493/r314494:

$ cat yuv_row_table.cpp
extern const int kCoefficientsRgbY[1];
const int kCoefficientsRgbY[1] = {0};
int main() { return 0; }

$ cat yuv_row_win.cpp
extern const int kCoefficientsRgbY[1];
void FastConvertYUVToRGB32Row_SSE() {
  __asm {
    movq      mm1, [kCoefficientsRgbY + 8 * eax]
  }
}

$ clang-cl.exe -m32 yuv_row_table.cpp yuv_row_win.cpp
yuv_row_win-f72966.obj : error LNK2019: unresolved external symbol kCoefficientsRgbY referenced in function "void __cdecl FastConvertYUVToRGB32Row_SSE(void)" (?FastConvertYUVToRGB32Row_SSE@@YAXXZ)
yuv_row_table.exe : fatal error LNK1120: 1 unresolved externals

[llvmbot]

it's basically due to the use of mangled names, which aforementioned patches/revs aren't bothered with introducing as part of the (IR) incarnation of the inline-asm string.
fix is relatively easy (and ugly), hope i'll get there anytime soon

[llvmbot]

@llvm/issue-subscribers-backend-x86

Author: None (llvmbot)

| | | | --- | --- | | Bugzilla Link | [35290](https://llvm.org/bz35290) | | Version | unspecified | | OS | Windows NT | | Blocks | llvm/llvm-project#11360 | | Reporter | LLVM Bugzilla Contributor | | CC | @jrmuizel,@RKSimon,@rnk |

Extended Description

I bisected this to r314493/r314494:

$ cat yuv_row_table.cpp
extern const int kCoefficientsRgbY[1];
const int kCoefficientsRgbY[1] = {0};
int main() { return 0; }

$ cat yuv_row_win.cpp
extern const int kCoefficientsRgbY[1];
void FastConvertYUVToRGB32Row_SSE() {
  __asm {
    movq      mm1, [kCoefficientsRgbY + 8 * eax]
  }
}

$ clang-cl.exe -m32 yuv_row_table.cpp yuv_row_win.cpp
yuv_row_win-f72966.obj : error LNK2019: unresolved external symbol kCoefficientsRgbY referenced in function "void __cdecl FastConvertYUVToRGB32Row_SSE(void)" (?FastConvertYUVToRGB32Row_SSE@@<!-- -->YAXXZ)
yuv_row_table.exe : fatal error LNK1120: 1 unresolved externals