[clang] Thread Safety Analysis: Support attributes on function pointers (PR #191187)

[Aaron Ballman via cfe-commits]

================
@@ -674,15 +674,28 @@ void Parser::ParseGNUAttributeArgs(
   // These may refer to the function arguments, but need to be parsed early to
   // participate in determining whether it's a redeclaration.
   std::optional<ParseScope> PrototypeScope;
-  if (normalizeAttrName(AttrName->getName()) == "enable_if" &&
-      D && D->isFunctionDeclarator()) {
-    const DeclaratorChunk::FunctionTypeInfo& FTI = D->getFunctionTypeInfo();
-    PrototypeScope.emplace(this, Scope::FunctionPrototypeScope |
-                                     Scope::FunctionDeclarationScope |
-                                     Scope::DeclScope);
-    for (unsigned i = 0; i != FTI.NumParams; ++i)
-      Actions.ActOnReenterCXXMethodParameter(
-          getCurScope(), dyn_cast_or_null<ParmVarDecl>(FTI.Params[i].Param));
+  if (D && (normalizeAttrName(AttrName->getName()) == "enable_if" ||
+            IsAttributeLateParsedStandard(*AttrName))) {
----------------
AaronBallman wrote:

>From Attr.td:
```
// Standard late attribute parsing
//
// This is language dependent. For example:
//
// * For C++ enables late parsing of a declaration attributes
// * For C does not enable late parsing of attributes
//
def LateAttrParseStandard : LateAttrParseKind<1>;
```
So these changes break that documentation, but I don't think you want the changes to only apply in C++ and not in C. I suspect you'll want these attributes to be using `LateAttrParseExperimentalExt` now instead, and be checking for that here. CC @rapidsna @hnrklssn for more opinions given this is tangential to bounds safety late parsing behavior.

https://github.com/llvm/llvm-project/pull/191187