Files
clang-p2996/llvm/test/CodeGen/X86/semantic-interposition-comdat.ll
Leonard Chan a0222ac1f9 [AsmPrinter] Do not define local aliases for global objects in a comdat
A global symbol that is defined in a comdat should not generate an alias since
call sites that would've referred to that symbol will refer to their own
independent local aliases rather than the surviving global comdat one. This
could result in something that looks like:

```
ld.lld: error: relocation refers to a discarded section: .text._ZN3fbl8internal18NullFunctionTargetIvJjjPjEED1Ev.stub
>>> defined in user-x64-clang/obj/system/ulib/minfs/libminfs.a(minfs._sources.file.cc.o)
>>> section group signature: _ZN3fbl8internal18NullFunctionTargetIvJjjPjEED1Ev.stub
>>> prevailing definition is in user-x64-clang/obj/system/ulib/minfs/libminfs.a(minfs._sources.vnode.cc.o)
>>> referenced by function.h:169 (../../zircon/system/ulib/fbl/include/fbl/function.h:169)
>>>               minfs._sources.file.cc.o:(minfs::File::AllocateAndCommitData(std::__2::unique_ptr<minfs::Transaction, std::__2::default_delete<minfs::Transaction> >)) in archive user-x64-clang/obj/system/ulib/minfs/libminfs.a
```

We ran into this when experimenting with a new C++ ABI for fuchsia
(refer to D72959) which takes relative offsets between comdat'd functions
which is why the normal C++ user wouldn't run into this.

Differential Revision: https://reviews.llvm.org/D77429
2020-04-06 13:48:05 -07:00

24 lines
379 B
LLVM

; RUN: llc -mtriple x86_64-unknown-linux-gnu %s -o - | FileCheck %s
$comdat_func = comdat any
; CHECK-LABEL: func2:
; CHECK-NEXT: .Lfunc2$local
declare void @func()
define hidden void @func2() {
entry:
call void @func()
ret void
}
; CHECK: comdat_func:
; CHECK-NOT: .Lcomdat_func$local
define hidden void @comdat_func() comdat {
entry:
call void @func()
ret void
}