Add a __builtin_addressof that performs the same functionality as the built-in
& operator (ignoring any overloaded operator& for the type). The purpose of
this builtin is for use in std::addressof, to allow it to be made constexpr;
the existing implementation technique (reinterpret_cast to some reference type,
take address, reinterpert_cast back) does not permit this because
reinterpret_cast between reference types is not permitted in a constant
expression in C++11 onwards.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@186053 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index e82f918..c0dd9fc 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -95,6 +95,22 @@
return false;
}
+/// Check that the argument to __builtin_addressof is a glvalue, and set the
+/// result type to the corresponding pointer type.
+static bool SemaBuiltinAddressof(Sema &S, CallExpr *TheCall) {
+ if (checkArgCount(S, TheCall, 1))
+ return true;
+
+ ExprResult Arg(S.Owned(TheCall->getArg(0)));
+ QualType ResultType = S.CheckAddressOfOperand(Arg, TheCall->getLocStart());
+ if (ResultType.isNull())
+ return true;
+
+ TheCall->setArg(0, Arg.take());
+ TheCall->setType(ResultType);
+ return false;
+}
+
ExprResult
Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
ExprResult TheCallResult(Owned(TheCall));
@@ -275,6 +291,10 @@
if (SemaBuiltinAnnotation(*this, TheCall))
return ExprError();
break;
+ case Builtin::BI__builtin_addressof:
+ if (SemaBuiltinAddressof(*this, TheCall))
+ return ExprError();
+ break;
}
// Since the target specific builtins for each arch overlap, only check those