| Issue |
180277
|
| Summary |
Branch coverage (single-byte counters) causes symbol redefinition error in inline assembly
|
| Labels |
coverage
|
| Assignees |
|
| Reporter |
gulfemsavrun
|
The support of single-byte counters for branch coverage has triggered a build failure in our code in [(arch-boot-zbi.cc).](https://cs.opensource.google/fuchsia/fuchsia/+/main:zircon/kernel/arch/arm64/phys/arch-boot-zbi.cc;l=55;drc=694892ad035d97638cb278997b92e28537318e79) The patch appears to cause a basic block containing inline assembly to be duplicated. Since the assembly has a hardcoded local label (`.L.ZbiBoot.disable_el2`), the duplication results in a `symbol already defined` error during compilation.
```
./arch-boot-zbi-f1fdbd.sh
../../zircon/kernel/arch/arm64/phys/arch-boot-zbi.cc:58:1: error: symbol '.L.ZbiBoot.disable_el2' is already defined
58 | .L.ZbiBoot.disable_el2:
| ^
<inline asm>:3:1: note: instantiated into assembly here
3 | .L.ZbiBoot.disable_el2:
| ^
../../zircon/kernel/arch/arm64/phys/arch-boot-zbi.cc:60:1: error: symbol '.L.ZbiBoot.mmu_possibly_off' is already defined
60 | .L.ZbiBoot.mmu_possibly_off:
| ^
<inline asm>:5:1: note: instantiated into assembly here
5 | .L.ZbiBoot.mmu_possibly_off:
| ^
../../zircon/kernel/arch/arm64/phys/arch-boot-zbi.cc:62:1: error: symbol '.L.ZbiBoot.disable_el1' is already defined
62 | .L.ZbiBoot.disable_el1:
| ^
<inline asm>:7:1: note: instantiated into assembly here
7 | .L.ZbiBoot.disable_el1:
| ^
../../zircon/kernel/arch/arm64/phys/arch-boot-zbi.cc:64:1: error: symbol '.L.ZbiBoot.mmu_off' is already defined
64 | .L.ZbiBoot.mmu_off:
| ^
<inline asm>:9:1: note: instantiated into assembly here
9 | .L.ZbiBoot.mmu_off:
| ^
../../zircon/kernel/arch/arm64/phys/arch-boot-zbi.cc:75:1: error: symbol '.L.ZbiBoot.end' is already defined
75 | .L.ZbiBoot.end:
| ^
<inline asm>:20:1: note: instantiated into assembly here
20 | .L.ZbiBoot.end:
| ^
5 errors generated.
```
I bisected the issue to this [commit](https://github.com/llvm/llvm-project/pull/113111)
I'm attaching a reproducer. [clang-crashreports.zip](https://github.com/user-attachments/files/25136648/clang-crashreports.zip)
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