https://reviews.llvm.org/D54188 marked "alias" targets as used in C to
fix -Wunused false positives. This patch extends the approach to handle
mangled names to support global scope names in C++ and the
`overloadable` attribute in C.
(Note: we should skip `UsingShadowDecl`, which would trigger an
assertion failure in `ItaniumMangleContextImpl::mangleCXXName`.
See regression test added by commit 1c2afbae9af22b58190c10e3517242d01d89d612.)
In addition, we mark ifunc targets as used to fix#63957 (temporarily
used by xz; ifunc was removed by
689ae24273)
While our approach has false negatives for namespace scope names, the
majority of alias/ifunc C++ uses (global scope with no overloads) are
handled.
Note: The following function with internal linkage but C language
linkage type is mangled in Clang but not in GCC. This inconsistency
makes alias/ifunc difficult to use in C++ with portability (#88593).
```
extern "C" {
static void f0() {}
// GCC: void g0() __attribute__((alias("_ZL2f0v")));
// Clang: void g0() __attribute__((alias("f0")));
}
```
Pull Request: https://github.com/llvm/llvm-project/pull/87130
https://reviews.llvm.org/D54188 marked "alias" targets as used in C to
fix -Wunused false positives. This patch extends the approach to handle
mangled names to support global scope names in C++ and the
`overloadable` attribute in C.
In addition, we mark ifunc targets as used to fix#63957.
While our approach has false negatives for namespace scope names, the
majority of alias/ifunc C++ uses (global scope with no overloads) are
handled.
Note: The following function with internal linkage but C language
linkage type is mangled in Clang but not in GCC. This inconsistency
makes alias/ifunc difficult to use in C++ with portability (#88593).
```
extern "C" {
static void f0() {}
// GCC: void g0() __attribute__((alias("_ZL2f0v")));
// Clang: void g0() __attribute__((alias("f0")));
}
```
Pull Request: https://github.com/llvm/llvm-project/pull/87130
This reverts commit 2105c32b32bf3360f524f1f3a1e5af605821eff8.
Reverting this follow-up commit as a prior commit (2107d87) is causing build bot test failures.
