1 files changed, 153 insertions, 54 deletions

diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp
index ba05a07..fc9c14f 100644
--- a/lib/Sema/Sema.cpp
+++ b/lib/Sema/Sema.cpp
@@ -23,44 +23,134 @@
 #include "clang/Basic/TargetInfo.h"
 using namespace clang;
 
+/// Determines whether we should have an a.k.a. clause when
+/// pretty-printing a type.  There are three main criteria:
+///
+/// 1) Some types provide very minimal sugar that doesn't impede the
+///    user's understanding --- for example, elaborated type
+///    specifiers.  If this is all the sugar we see, we don't want an
+///    a.k.a. clause.
+/// 2) Some types are technically sugared but are much more familiar
+///    when seen in their sugared form --- for example, va_list,
+///    vector types, and the magic Objective C types.  We don't
+///    want to desugar these, even if we do produce an a.k.a. clause.
+/// 3) Some types may have already been desugared previously in this diagnostic.
+///    if this is the case, doing another "aka" would just be clutter.
+///
+static bool ShouldAKA(ASTContext &Context, QualType QT,
+                      const Diagnostic::ArgumentValue *PrevArgs,
+                      unsigned NumPrevArgs,
+                      QualType &DesugaredQT) {
+  QualType InputTy = QT;
+  
+  bool AKA = false;
+  QualifierCollector Qc;
+
+  while (true) {
+    const Type *Ty = Qc.strip(QT);
+
+    // Don't aka just because we saw an elaborated type...
+    if (isa<ElaboratedType>(Ty)) {
+      QT = cast<ElaboratedType>(Ty)->desugar();
+      continue;
+    }
+
+    // ...or a qualified name type...
+    if (isa<QualifiedNameType>(Ty)) {
+      QT = cast<QualifiedNameType>(Ty)->desugar();
+      continue;
+    }
+
+    // ...or a substituted template type parameter.
+    if (isa<SubstTemplateTypeParmType>(Ty)) {
+      QT = cast<SubstTemplateTypeParmType>(Ty)->desugar();
+      continue;
+    }
+      
+    // Don't desugar template specializations. 
+    if (isa<TemplateSpecializationType>(Ty))
+      break;
+
+    // Don't desugar magic Objective-C types.
+    if (QualType(Ty,0) == Context.getObjCIdType() ||
+        QualType(Ty,0) == Context.getObjCClassType() ||
+        QualType(Ty,0) == Context.getObjCSelType() ||
+        QualType(Ty,0) == Context.getObjCProtoType())
+      break;
+
+    // Don't desugar va_list.
+    if (QualType(Ty,0) == Context.getBuiltinVaListType())
+      break;
+
+    // Otherwise, do a single-step desugar.
+    QualType Underlying;
+    bool IsSugar = false;
+    switch (Ty->getTypeClass()) {
+#define ABSTRACT_TYPE(Class, Base)
+#define TYPE(Class, Base) \
+    case Type::Class: { \
+      const Class##Type *CTy = cast<Class##Type>(Ty); \
+      if (CTy->isSugared()) { \
+        IsSugar = true; \
+        Underlying = CTy->desugar(); \
+      } \
+      break; \
+    }
+#include "clang/AST/TypeNodes.def"
+    }
+
+    // If it wasn't sugared, we're done.
+    if (!IsSugar)
+      break;
+
+    // If the desugared type is a vector type, we don't want to expand
+    // it, it will turn into an attribute mess. People want their "vec4".
+    if (isa<VectorType>(Underlying))
+      break;
+
+    // Otherwise, we're tearing through something opaque; note that
+    // we'll eventually need an a.k.a. clause and keep going.
+    AKA = true;
+    QT = Underlying;
+    continue;
+  }
+
+  // If we never tore through opaque sugar, don't print aka.
+  if (!AKA) return false;
+
+  // If we did, check to see if we already desugared this type in this
+  // diagnostic.  If so, don't do it again.
+  for (unsigned i = 0; i != NumPrevArgs; ++i) {
+    // TODO: Handle ak_declcontext case.
+    if (PrevArgs[i].first == Diagnostic::ak_qualtype) {
+      void *Ptr = (void*)PrevArgs[i].second;
+      QualType PrevTy(QualType::getFromOpaquePtr(Ptr));
+      if (PrevTy == InputTy)
+        return false;
+    }
+  }
+  
+  DesugaredQT = Qc.apply(QT);
+  return true;
+}
+
 /// \brief Convert the given type to a string suitable for printing as part of 
 /// a diagnostic. 
 ///
 /// \param Context the context in which the type was allocated
 /// \param Ty the type to print
-static std::string ConvertTypeToDiagnosticString(ASTContext &Context,
-                                                 QualType Ty) {
+static std::string
+ConvertTypeToDiagnosticString(ASTContext &Context, QualType Ty,
+                              const Diagnostic::ArgumentValue *PrevArgs,
+                              unsigned NumPrevArgs) {
   // FIXME: Playing with std::string is really slow.
   std::string S = Ty.getAsString(Context.PrintingPolicy);
   
-  // If this is a sugared type (like a typedef, typeof, etc), then unwrap one
-  // level of the sugar so that the type is more obvious to the user.
-  QualType DesugaredTy = Ty.getDesugaredType();
-  
-  if (Ty != DesugaredTy &&
-      // If the desugared type is a vector type, we don't want to expand it,
-      // it will turn into an attribute mess. People want their "vec4".
-      !isa<VectorType>(DesugaredTy) &&
-      
-      // Don't aka just because we saw an elaborated type...
-      (!isa<ElaboratedType>(Ty) ||
-       cast<ElaboratedType>(Ty)->desugar() != DesugaredTy) &&
-      
-      // ...or a qualified name type...
-      (!isa<QualifiedNameType>(Ty) ||
-       cast<QualifiedNameType>(Ty)->desugar() != DesugaredTy) &&
-      
-      // ...or a non-dependent template specialization.
-      (!isa<TemplateSpecializationType>(Ty) || Ty->isDependentType()) &&
-      
-      // Don't desugar magic Objective-C types.
-      Ty.getUnqualifiedType() != Context.getObjCIdType() &&
-      Ty.getUnqualifiedType() != Context.getObjCClassType() &&
-      Ty.getUnqualifiedType() != Context.getObjCSelType() &&
-      Ty.getUnqualifiedType() != Context.getObjCProtoType() &&
-      
-      // Not va_list.
-      Ty.getUnqualifiedType() != Context.getBuiltinVaListType()) {
+  // Consider producing an a.k.a. clause if removing all the direct
+  // sugar gives us something "significantly different".
+
+  QualType DesugaredTy;
+  if (ShouldAKA(Context, Ty, PrevArgs, NumPrevArgs, DesugaredTy)) {
     S = "'"+S+"' (aka '";
     S += DesugaredTy.getAsString(Context.PrintingPolicy);
     S += "')";
@@ -76,21 +166,27 @@ static std::string ConvertTypeToDiagnosticString(ASTContext &Context,
 static void ConvertArgToStringFn(Diagnostic::ArgumentKind Kind, intptr_t Val,
                                  const char *Modifier, unsigned ModLen,
                                  const char *Argument, unsigned ArgLen,
+                                 const Diagnostic::ArgumentValue *PrevArgs,
+                                 unsigned NumPrevArgs,
                                  llvm::SmallVectorImpl<char> &Output,
                                  void *Cookie) {
   ASTContext &Context = *static_cast<ASTContext*>(Cookie);
 
   std::string S;
   bool NeedQuotes = true;
-  if (Kind == Diagnostic::ak_qualtype) {
+  
+  switch (Kind) {
+  default: assert(0 && "unknown ArgumentKind");
+  case Diagnostic::ak_qualtype: {
     assert(ModLen == 0 && ArgLen == 0 &&
            "Invalid modifier for QualType argument");
 
     QualType Ty(QualType::getFromOpaquePtr(reinterpret_cast<void*>(Val)));
-    S = ConvertTypeToDiagnosticString(Context, Ty);
+    S = ConvertTypeToDiagnosticString(Context, Ty, PrevArgs, NumPrevArgs);
     NeedQuotes = false;
-  } else if (Kind == Diagnostic::ak_declarationname) {
-
+    break;
+  }
+  case Diagnostic::ak_declarationname: {
     DeclarationName N = DeclarationName::getFromOpaqueInteger(Val);
     S = N.getAsString();
 
@@ -101,7 +197,9 @@ static void ConvertArgToStringFn(Diagnostic::ArgumentKind Kind, intptr_t Val,
     else
       assert(ModLen == 0 && ArgLen == 0 &&
              "Invalid modifier for DeclarationName argument");
-  } else if (Kind == Diagnostic::ak_nameddecl) {
+    break;
+  }
+  case Diagnostic::ak_nameddecl: {
     bool Qualified;
     if (ModLen == 1 && Modifier[0] == 'q' && ArgLen == 0)
       Qualified = true;
@@ -110,30 +208,30 @@ static void ConvertArgToStringFn(Diagnostic::ArgumentKind Kind, intptr_t Val,
            "Invalid modifier for NamedDecl* argument");
       Qualified = false;
     }
-    reinterpret_cast<NamedDecl*>(Val)->getNameForDiagnostic(S,
-                                                         Context.PrintingPolicy,
-                                                            Qualified);
-  } else if (Kind == Diagnostic::ak_nestednamespec) {
+    reinterpret_cast<NamedDecl*>(Val)->
+      getNameForDiagnostic(S, Context.PrintingPolicy, Qualified);
+    break;
+  }
+  case Diagnostic::ak_nestednamespec: {
     llvm::raw_string_ostream OS(S);
-    reinterpret_cast<NestedNameSpecifier*> (Val)->print(OS,
-                                                        Context.PrintingPolicy);
+    reinterpret_cast<NestedNameSpecifier*>(Val)->print(OS,
+                                                       Context.PrintingPolicy);
     NeedQuotes = false;
-  } else {
-    assert(Kind == Diagnostic::ak_declcontext);
+    break;
+  }
+  case Diagnostic::ak_declcontext: {
     DeclContext *DC = reinterpret_cast<DeclContext *> (Val);
-    NeedQuotes = false;
-    if (!DC) {
-      assert(false && "Should never have a null declaration context");
-      S = "unknown context";
-    } else if (DC->isTranslationUnit()) {
+    assert(DC && "Should never have a null declaration context");
+    
+    if (DC->isTranslationUnit()) {
       // FIXME: Get these strings from some localized place
       if (Context.getLangOptions().CPlusPlus)
         S = "the global namespace";
       else
         S = "the global scope";
     } else if (TypeDecl *Type = dyn_cast<TypeDecl>(DC)) {
-      S = ConvertTypeToDiagnosticString(Context, Context.getTypeDeclType(Type));
-      NeedQuotes = false;
+      S = ConvertTypeToDiagnosticString(Context, Context.getTypeDeclType(Type),
+                                        PrevArgs, NumPrevArgs);
     } else {
       // FIXME: Get these strings from some localized place
       NamedDecl *ND = cast<NamedDecl>(DC);
@@ -147,8 +245,10 @@ static void ConvertArgToStringFn(Diagnostic::ArgumentKind Kind, intptr_t Val,
       S += "'";
       ND->getNameForDiagnostic(S, Context.PrintingPolicy, true);
       S += "'";
-      NeedQuotes = false;
     }
+    NeedQuotes = false;
+    break;
+  }
   }
 
   if (NeedQuotes)
@@ -361,9 +461,8 @@ void Sema::ActOnEndOfTranslationUnit() {
       // Set the length of the array to 1 (C99 6.9.2p5).
       Diag(VD->getLocation(), diag::warn_tentative_incomplete_array);
       llvm::APInt One(Context.getTypeSize(Context.getSizeType()), true);
-      QualType T
-        = Context.getConstantArrayWithoutExprType(ArrayT->getElementType(),
-                                                  One, ArrayType::Normal, 0);
+      QualType T = Context.getConstantArrayType(ArrayT->getElementType(),
+                                                One, ArrayType::Normal, 0);
       VD->setType(T);
     } else if (RequireCompleteType(VD->getLocation(), VD->getType(),
                                    diag::err_tentative_def_incomplete_type))