[PATCH] Add a mangler entry point for TBAA rather than using RTTI directly

[Reid Kleckner]

    - Rename mangleTBAAName to mangleTypeName for debug info uniquing

Hi timurrrr,

http://llvm-reviews.chandlerc.com/D2153

CHANGE SINCE LAST DIFF
  http://llvm-reviews.chandlerc.com/D2153?vs=5473&id=5665#toc

BRANCH
  mangle-tbaa

ARCANIST PROJECT
  clang

Files:
  include/clang/AST/Mangle.h
  lib/AST/ItaniumMangle.cpp
  lib/AST/MicrosoftMangle.cpp
  lib/CodeGen/CodeGenTBAA.cpp
  test/CodeGen/tbaa-ms-abi.cpp

Index: include/clang/AST/Mangle.h
===================================================================
--- include/clang/AST/Mangle.h
+++ include/clang/AST/Mangle.h
@@ -148,6 +148,12 @@
   virtual void mangleDynamicAtExitDestructor(const VarDecl *D,
                                              raw_ostream &) = 0;
 
+  /// Generates a unique string for an externally visible type for use with TBAA
+  /// or type uniquing.
+  /// TODO: Extend this to internal types by generating names that are unique
+  /// across translation units so it can be used with LTO.
+  virtual void mangleTypeName(QualType T, raw_ostream &) = 0;
+
   /// @}
 };
 
Index: lib/AST/ItaniumMangle.cpp
===================================================================
--- lib/AST/ItaniumMangle.cpp
+++ lib/AST/ItaniumMangle.cpp
@@ -144,6 +144,7 @@
                            raw_ostream &);
   void mangleCXXRTTI(QualType T, raw_ostream &);
   void mangleCXXRTTIName(QualType T, raw_ostream &);
+  void mangleTypeName(QualType T, raw_ostream &);
   void mangleCXXCtor(const CXXConstructorDecl *D, CXXCtorType Type,
                      raw_ostream &);
   void mangleCXXDtor(const CXXDestructorDecl *D, CXXDtorType Type,
@@ -3784,6 +3785,10 @@
   Mangler.mangleType(Ty);
 }
 
+void ItaniumMangleContextImpl::mangleTypeName(QualType Ty, raw_ostream &Out) {
+  mangleCXXRTTIName(Ty, Out);
+}
+
 ItaniumMangleContext *
 ItaniumMangleContext::create(ASTContext &Context, DiagnosticsEngine &Diags) {
   return new ItaniumMangleContextImpl(Context, Diags);
Index: lib/AST/MicrosoftMangle.cpp
===================================================================
--- lib/AST/MicrosoftMangle.cpp
+++ lib/AST/MicrosoftMangle.cpp
@@ -197,6 +197,7 @@
                                 raw_ostream &Out);
   virtual void mangleCXXRTTI(QualType T, raw_ostream &);
   virtual void mangleCXXRTTIName(QualType T, raw_ostream &);
+  virtual void mangleTypeName(QualType T, raw_ostream &);
   virtual void mangleCXXCtor(const CXXConstructorDecl *D, CXXCtorType Type,
                              raw_ostream &);
   virtual void mangleCXXDtor(const CXXDestructorDecl *D, CXXDtorType Type,
@@ -2019,6 +2020,14 @@
     << T.getBaseTypeIdentifier();
 }
 
+void MicrosoftMangleContextImpl::mangleTypeName(QualType T, raw_ostream &Out) {
+  // This is just a made up unique string for the purposes of tbaa.  undname
+  // does *not* know how to demangle it.
+  MicrosoftCXXNameMangler Mangler(*this, Out);
+  Mangler.getStream() << '?';
+  Mangler.mangleType(T, SourceRange());
+}
+
 void MicrosoftMangleContextImpl::mangleCXXCtor(const CXXConstructorDecl *D,
                                                CXXCtorType Type,
                                                raw_ostream &Out) {
Index: lib/CodeGen/CodeGenTBAA.cpp
===================================================================
--- lib/CodeGen/CodeGenTBAA.cpp
+++ lib/CodeGen/CodeGenTBAA.cpp
@@ -152,11 +152,9 @@
     if (!Features.CPlusPlus || !ETy->getDecl()->isExternallyVisible())
       return MetadataCache[Ty] = getChar();
 
-    // TODO: This is using the RTTI name. Is there a better way to get
-    // a unique string for a type?
     SmallString<256> OutName;
     llvm::raw_svector_ostream Out(OutName);
-    MContext.mangleCXXRTTIName(QualType(ETy, 0), Out);
+    MContext.mangleTypeName(QualType(ETy, 0), Out);
     Out.flush();
     return MetadataCache[Ty] = createTBAAScalarType(OutName, getChar());
   }
@@ -268,13 +266,11 @@
           FieldNode, Layout.getFieldOffset(idx) / Context.getCharWidth()));
     }
 
-    // TODO: This is using the RTTI name. Is there a better way to get
-    // a unique string for a type?
     SmallString<256> OutName;
     if (Features.CPlusPlus) {
-      // Don't use mangleCXXRTTIName for C code.
+      // Don't use the mangler for C code.
       llvm::raw_svector_ostream Out(OutName);
-      MContext.mangleCXXRTTIName(QualType(Ty, 0), Out);
+      MContext.mangleTypeName(QualType(Ty, 0), Out);
       Out.flush();
     } else {
       OutName = RD->getName();
Index: test/CodeGen/tbaa-ms-abi.cpp
===================================================================
--- /dev/null
+++ test/CodeGen/tbaa-ms-abi.cpp
@@ -0,0 +1,22 @@
+// RUN: %clang_cc1 -cxx-abi microsoft -triple i686-pc-win32 -disable-llvm-optzns -emit-llvm -o - -O1 %s | FileCheck %s
+//
+// Test that TBAA works in the Microsoft C++ ABI.  We used to error out while
+// attempting to mangle RTTI.
+
+struct StructA {
+  int a;
+};
+
+struct StructB : virtual StructA {
+  StructB();
+};
+
+StructB::StructB() {
+  a = 42;
+// CHECK: store i32 42, i32* {{.*}}, !tbaa [[TAG_A_i32:!.*]]
+}
+
+// CHECK: [[TYPE_CHAR:!.*]] = metadata !{metadata !"omnipotent char", metadata
+// CHECK: [[TYPE_INT:!.*]] = metadata !{metadata !"int", metadata [[TYPE_CHAR]], i64 0}
+// CHECK: [[TAG_A_i32]] = metadata !{metadata [[TYPE_A:!.*]], metadata [[TYPE_INT]], i64 0}
+// CHECK: [[TYPE_A]] = metadata !{metadata !"?AUStructA@@", metadata [[TYPE_INT]], i64 0}
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