445956443b
This patch adds a case to `CheckMultiVersionAdditionalDecl()` that
detects redeclarations of `target_clones` functions which omit the
attribute, and makes sure they are marked as redeclarations. It also
updates the comment at the call site of
`CheckMultiVersionAdditionalDecl()` to reflect this.
Previously, `target_clones` multiversioned functions that omitted the
attribute from subsequent declarations would cause Clang to hit an
`llvm_unreachable` and crash. In the following example, the second
declaration (the function definition) should inherit the `target_clones`
attribute from the first declaration (the forward declaration):
```
__attribute__((target_clones("arch=atom", "default")))
void foo(void);
void foo(void) { /* ... */ }
```
However, `CheckMultiVersionAdditionalDecl()` was not recognizing the
function definition as a redeclaration of the forward declaration, which
prevented `Sema::MergeFunctionDecl()` from automatically inheriting the
attribute.
A side effect of this fix is that Clang now catches redeclarations of
`target_clones` functions that have conflicting types, which previously
caused Clang to crash by hitting that same `llvm_unreachable`. The
`bad_overload1` case in `clang/test/Sema/attr-target-clones.c` has been
updated to reflect this.
Fixes #165517
Fixes #129483
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