[-cxx-abi microsoft] Mangle __uuidof correctly into template parameters

Summary:
It seems that __uuidof introduces a global extern "C" declaration of
type __s_GUID.  However, our implementation of __uuidof does not provide
such a declaration and thus must open-code the mangling for __uuidof in
template parameters.

This allows us to codegen scoped COM pointers and other such things.

This fixes PR16836.
Depends on D1356.

Reviewers: rnk, cdavis5x, rsmith

Reviewed By: rnk

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1357

llvm-svn: 188252

1 files changed, 28 insertions, 0 deletions

diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index 765b14d49e5..9f4df3a4548 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -83,6 +83,7 @@ public:
 
   void mangle(const NamedDecl *D, StringRef Prefix = "\01?");
   void mangleName(const NamedDecl *ND);
+  void mangleDeclaration(const NamedDecl *ND);
   void mangleFunctionEncoding(const FunctionDecl *FD);
   void mangleVariableEncoding(const VarDecl *VD);
   void mangleNumber(int64_t Number);
@@ -855,6 +856,33 @@ MicrosoftCXXNameMangler::mangleExpression(const Expr *E) {
     return;
   }
 
+  const CXXUuidofExpr *UE = 0;
+  if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
+    if (UO->getOpcode() == UO_AddrOf)
+      UE = dyn_cast<CXXUuidofExpr>(UO->getSubExpr());
+  } else
+    UE = dyn_cast<CXXUuidofExpr>(E);
+
+  if (UE) {
+    // This CXXUuidofExpr is mangled as-if it were actually a VarDecl from
+    // const __s_GUID _GUID_{lower case UUID with underscores}
+    StringRef Uuid = UE->getUuidAsStringRef(Context.getASTContext());
+    std::string Name = "_GUID_" + Uuid.lower();
+    std::replace(Name.begin(), Name.end(), '-', '_');
+
+    // If we had to peak through an address-of operator, treat this like we are
+    // dealing with a pointer type.  Otherwise, treat it like a const reference.
+    //
+    // N.B. This matches up with the handling of TemplateArgument::Declaration
+    // in mangleTemplateArg
+    if (UE == E)
+      Out << "$E?";
+    else
+      Out << "$1?";
+    Out << Name << "@@3U__s_GUID@@B";
+    return;
+  }
+
   // As bad as this diagnostic is, it's better than crashing.
   DiagnosticsEngine &Diags = Context.getDiags();
   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,