In C++, if the user redeclares a builtin function with a type that is
inconsistent with the type that the builtin *should* have, forget
about the builtin altogether: we don't want subsequence analyses,
CodeGen, etc., to think that we have a proper builtin function.
C is protected from errors here because it allows one to use a
library builtin without having a declaration, and detects inconsistent
(re-)declarations of builtins during declaration merging. C++ was
unprotected, and therefore would crash.
Fixes PR8839.
llvm-svn: 122351
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index ad0c077..bc91eb0 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -4285,6 +4285,18 @@
// during delayed parsing anyway.
if (!CurContext->isRecord())
CheckCXXDefaultArguments(NewFD);
+
+ // If this function declares a builtin function, check the type of this
+ // declaration against the expected type for the builtin.
+ if (unsigned BuiltinID = NewFD->getBuiltinID()) {
+ ASTContext::GetBuiltinTypeError Error;
+ QualType T = Context.GetBuiltinType(BuiltinID, Error);
+ if (!T.isNull() && !Context.hasSameType(T, NewFD->getType())) {
+ // The type of this function differs from the type of the builtin,
+ // so forget about the builtin entirely.
+ Context.BuiltinInfo.ForgetBuiltin(BuiltinID, Context.Idents);
+ }
+ }
}
}