Initial step toward supporting qualification conversions (C++ 4.4).

Changes:
  - Sema::IsQualificationConversion determines whether we have a qualification
    conversion.
  - Sema::CheckSingleAssignment constraints now follows the C++ rules in C++,
    performing an implicit conversion from the right-hand side to the type of
    the left-hand side rather than checking based on the C notion of 
    "compatibility". We now rely on the implicit-conversion code to
    determine whether the conversion can happen or
    not. Sema::TryCopyInitialization has an ugly reference-related
    hack to cope with the initialization of references, for now.
  - When building DeclRefExprs, strip away the reference type, since
    there are no expressions whose type is a reference. We'll need to
    do this throughout Sema.
  - Expr::isLvalue now permits functions to be lvalues in C++ (but not
  in C).



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@57935 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 17 insertions, 0 deletions

diff --git a/lib/Sema/SemaType.cpp b/lib/Sema/SemaType.cpp
index f1edabfa7e..942d7063a1 100644
--- a/lib/Sema/SemaType.cpp
+++ b/lib/Sema/SemaType.cpp
@@ -500,6 +500,23 @@ QualType Sema::GetTypeForDeclarator(Declarator &D, Scope *S) {
   return T;
 }
 
+/// GetNonReferenceType - If Type is a reference type (e.g., const
+/// int&), returns the type that the reference refers to ("const
+/// int"). Otherwise, returns the type itself. This routine is used
+/// throughout to implement C++ 5p6:
+///
+///   If an expression initially has the type "reference to T" (8.3.2,
+///   8.5.3), the type is adjusted to "T" prior to any further
+///   analysis, the expression designates the object or function
+///   denoted by the reference, and the expression is an lvalue.
+QualType Sema::GetNonReferenceType(QualType Type)
+{
+  if (const ReferenceType *RefType = Type->getAsReferenceType())
+    return RefType->getPointeeType();
+  else
+    return Type;
+}
+
 /// ObjCGetTypeForMethodDefinition - Builds the type for a method definition
 /// declarator
 QualType Sema::ObjCGetTypeForMethodDefinition(DeclTy *D) {