[AST] Introduce a new DecayedType sugar node

The goal of this sugar node is to be able to look at an arbitrary
FunctionType and tell if any of the parameters were decayed from an
array or function type.  Ultimately this is necessary to implement
Microsoft's C++ name mangling scheme, which mangles decayed arrays
differently from normal pointers.

Reviewers: rsmith

Differential Revision: http://llvm-reviews.chandlerc.com/D1014

llvm-svn: 184763

2 files changed, 8 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index e38327a9270..9d2b23ed185 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -2069,6 +2069,10 @@ llvm::DIType CGDebugInfo::CreateTypeNode(QualType Ty, llvm::DIFile Unit,
     return CreateType(cast<ComplexType>(Ty));
   case Type::Pointer:
     return CreateType(cast<PointerType>(Ty), Unit);
+  case Type::Decayed:
+    // Decayed types are just pointers in LLVM and DWARF.
+    return CreateType(
+        cast<PointerType>(cast<DecayedType>(Ty)->getDecayedType()), Unit);
   case Type::BlockPointer:
     return CreateType(cast<BlockPointerType>(Ty), Unit);
   case Type::Typedef:
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 297fc655e44..c6b498cd586 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -1273,6 +1273,10 @@ void CodeGenFunction::EmitVariablyModifiedType(QualType type) {
     case Type::ObjCObjectPointer:
       llvm_unreachable("type class is never variably-modified!");
 
+    case Type::Decayed:
+      type = cast<DecayedType>(ty)->getPointeeType();
+      break;
+
     case Type::Pointer:
       type = cast<PointerType>(ty)->getPointeeType();
       break;