Implement the C++0x deduced 'auto' feature.

This fixes PR 8738, 9060 and 9132.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126069 91177308-0d34-0410-b5e6-96231b3b80d8

8 files changed, 132 insertions, 24 deletions

diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 50c295f241..945dfb87f2 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -380,10 +380,6 @@ void ASTContext::InitBuiltinTypes() {
   // Placeholder type for functions.
   InitBuiltinType(OverloadTy,          BuiltinType::Overload);
 
-  // Placeholder type for C++0x auto declarations whose real type has
-  // not yet been deduced.
-  InitBuiltinType(UndeducedAutoTy,     BuiltinType::UndeducedAuto);
-
   // C99 6.2.5p11.
   FloatComplexTy      = getComplexType(FloatTy);
   DoubleComplexTy     = getComplexType(DoubleTy);
@@ -875,6 +871,12 @@ ASTContext::getTypeInfo(const Type *T) const {
     return getTypeInfo(cast<SubstTemplateTypeParmType>(T)->
                        getReplacementType().getTypePtr());
 
+  case Type::Auto: {
+    const AutoType *A = cast<AutoType>(T);
+    assert(A->isDeduced() && "Cannot request the size of a dependent type");
+    return getTypeInfo(cast<AutoType>(T)->getDeducedType().getTypePtr());
+  }
+
   case Type::Paren:
     return getTypeInfo(cast<ParenType>(T)->getInnerType().getTypePtr());
 
@@ -1532,6 +1534,7 @@ QualType ASTContext::getVariableArrayDecayedType(QualType type) const {
   case Type::DependentTemplateSpecialization:
   case Type::TemplateTypeParm:
   case Type::SubstTemplateTypeParmPack:
+  case Type::Auto:
   case Type::PackExpansion:
     llvm_unreachable("type should never be variably-modified");
 
@@ -2680,6 +2683,14 @@ QualType ASTContext::getDecltypeType(Expr *e) const {
   return QualType(dt, 0);
 }
 
+/// getAutoType - Unlike many "get<Type>" functions, we don't unique
+/// AutoType AST's.
+QualType ASTContext::getAutoType(QualType DeducedType) const {
+  AutoType *at = new (*this, TypeAlignment) AutoType(DeducedType);
+  Types.push_back(at);
+  return QualType(at, 0);
+}
+
 /// getTagDeclType - Return the unique reference to the type for the
 /// specified TagDecl (struct/union/class/enum) decl.
 QualType ASTContext::getTagDeclType(const TagDecl *Decl) const {
diff --git a/lib/AST/ASTDiagnostic.cpp b/lib/AST/ASTDiagnostic.cpp
index 9870b515c6..5bf8a38199 100644
--- a/lib/AST/ASTDiagnostic.cpp
+++ b/lib/AST/ASTDiagnostic.cpp
@@ -28,18 +28,26 @@ static QualType Desugar(ASTContext &Context, QualType QT, bool &ShouldAKA) {
     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();
+    if (const ElaboratedType *ET = dyn_cast<ElaboratedType>(Ty)) {
+      QT = ET->desugar();
       continue;
     }
     // ... or a paren type ...
-    if (isa<ParenType>(Ty)) {
-      QT = cast<ParenType>(Ty)->desugar();
+    if (const ParenType *PT = dyn_cast<ParenType>(Ty)) {
+      QT = PT->desugar();
       continue;
     }
-    // ...or a substituted template type parameter.
-    if (isa<SubstTemplateTypeParmType>(Ty)) {
-      QT = cast<SubstTemplateTypeParmType>(Ty)->desugar();
+    // ...or a substituted template type parameter ...
+    if (const SubstTemplateTypeParmType *ST =
+          dyn_cast<SubstTemplateTypeParmType>(Ty)) {
+      QT = ST->desugar();
+      continue;
+    }
+    // ... or an auto type.
+    if (const AutoType *AT = dyn_cast<AutoType>(Ty)) {
+      if (!AT->isSugared())
+        break;
+      QT = AT->desugar();
       continue;
     }
 
diff --git a/lib/AST/ASTImporter.cpp b/lib/AST/ASTImporter.cpp
index a1e0070422..65c0a3bb61 100644
--- a/lib/AST/ASTImporter.cpp
+++ b/lib/AST/ASTImporter.cpp
@@ -64,6 +64,7 @@ namespace {
     // FIXME: DependentTypeOfExprType
     QualType VisitTypeOfType(const TypeOfType *T);
     QualType VisitDecltypeType(const DecltypeType *T);
+    QualType VisitAutoType(const AutoType *T);
     // FIXME: DependentDecltypeType
     QualType VisitRecordType(const RecordType *T);
     QualType VisitEnumType(const EnumType *T);
@@ -604,6 +605,13 @@ static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
       return false;
     break;
 
+  case Type::Auto:
+    if (!IsStructurallyEquivalent(Context,
+                                  cast<AutoType>(T1)->getDeducedType(),
+                                  cast<AutoType>(T2)->getDeducedType()))
+      return false;
+    break;
+
   case Type::Record:
   case Type::Enum:
     if (!IsStructurallyEquivalent(Context,
@@ -1347,9 +1355,6 @@ QualType ASTNodeImporter::VisitBuiltinType(const BuiltinType *T) {
     
   case BuiltinType::Overload: return Importer.getToContext().OverloadTy;
   case BuiltinType::Dependent: return Importer.getToContext().DependentTy;
-  case BuiltinType::UndeducedAuto: 
-    // FIXME: Make sure that the "to" context supports C++0x!
-    return Importer.getToContext().UndeducedAutoTy;
 
   case BuiltinType::ObjCId:
     // FIXME: Make sure that the "to" context supports Objective-C!
@@ -1550,6 +1555,7 @@ QualType ASTNodeImporter::VisitTypeOfType(const TypeOfType *T) {
 }
 
 QualType ASTNodeImporter::VisitDecltypeType(const DecltypeType *T) {
+  // FIXME: Make sure that the "to" context supports C++0x!
   Expr *ToExpr = Importer.Import(T->getUnderlyingExpr());
   if (!ToExpr)
     return QualType();
@@ -1557,6 +1563,19 @@ QualType ASTNodeImporter::VisitDecltypeType(const DecltypeType *T) {
   return Importer.getToContext().getDecltypeType(ToExpr);
 }
 
+QualType ASTNodeImporter::VisitAutoType(const AutoType *T) {
+  // FIXME: Make sure that the "to" context supports C++0x!
+  QualType FromDeduced = T->getDeducedType();
+  QualType ToDeduced;
+  if (!FromDeduced.isNull()) {
+    ToDeduced = Importer.Import(FromDeduced);
+    if (ToDeduced.isNull())
+      return QualType();
+  }
+  
+  return Importer.getToContext().getAutoType(ToDeduced);
+}
+
 QualType ASTNodeImporter::VisitRecordType(const RecordType *T) {
   RecordDecl *ToDecl
     = dyn_cast_or_null<RecordDecl>(Importer.Import(T->getDecl()));
diff --git a/lib/AST/ItaniumMangle.cpp b/lib/AST/ItaniumMangle.cpp
index 2819a7e4b9..d66c374cbe 100644
--- a/lib/AST/ItaniumMangle.cpp
+++ b/lib/AST/ItaniumMangle.cpp
@@ -1313,9 +1313,6 @@ void CXXNameMangler::mangleType(const BuiltinType *T) {
     assert(false &&
            "Overloaded and dependent types shouldn't get to name mangling");
     break;
-  case BuiltinType::UndeducedAuto:
-    assert(0 && "Should not see undeduced auto here");
-    break;
   case BuiltinType::ObjCId: Out << "11objc_object"; break;
   case BuiltinType::ObjCClass: Out << "10objc_class"; break;
   case BuiltinType::ObjCSel: Out << "13objc_selector"; break;
@@ -1648,6 +1645,12 @@ void CXXNameMangler::mangleType(const DecltypeType *T) {
   Out << 'E';
 }
 
+void CXXNameMangler::mangleType(const AutoType *T) {
+  QualType D = T->getDeducedType();
+  assert(!D.isNull() && "can't mangle undeduced auto type");
+  mangleType(D);
+}
+
 void CXXNameMangler::mangleIntegerLiteral(QualType T,
                                           const llvm::APSInt &Value) {
   //  <expr-primary> ::= L <type> <value number> E # integer literal
diff --git a/lib/AST/MicrosoftMangle.cpp b/lib/AST/MicrosoftMangle.cpp
index 7aafac0ad0..4bf7f23a0a 100644
--- a/lib/AST/MicrosoftMangle.cpp
+++ b/lib/AST/MicrosoftMangle.cpp
@@ -720,9 +720,6 @@ void MicrosoftCXXNameMangler::mangleType(const BuiltinType *T) {
     assert(false &&
            "Overloaded and dependent types shouldn't get to name mangling");
     break;
-  case BuiltinType::UndeducedAuto:
-    assert(0 && "Should not see undeduced auto here");
-    break;
   case BuiltinType::ObjCId: Out << "PAUobjc_object@@"; break;
   case BuiltinType::ObjCClass: Out << "PAUobjc_class@@"; break;
   case BuiltinType::ObjCSel: Out << "PAUobjc_selector@@"; break;
@@ -1119,6 +1116,10 @@ void MicrosoftCXXNameMangler::mangleType(const DecltypeType *T) {
   assert(false && "Don't know how to mangle DecltypeTypes yet!");
 }
 
+void MicrosoftCXXNameMangler::mangleType(const AutoType *T) {
+  assert(false && "Don't know how to mangle AutoTypes yet!");
+}
+
 void MicrosoftMangleContext::mangleName(const NamedDecl *D,
                                         llvm::raw_ostream &Out) {
   assert((isa<FunctionDecl>(D) || isa<VarDecl>(D)) &&
diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index 0130b13b94..b03314e11d 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -432,6 +432,61 @@ CXXRecordDecl *Type::getAsCXXRecordDecl() const {
   return 0;
 }
 
+namespace {
+  class GetContainedAutoVisitor :
+    public TypeVisitor<GetContainedAutoVisitor, AutoType*> {
+  public:
+    using TypeVisitor<GetContainedAutoVisitor, AutoType*>::Visit;
+    AutoType *Visit(QualType T) {
+      if (T.isNull())
+        return 0;
+      return Visit(T.getTypePtr());
+    }
+
+    // The 'auto' type itself.
+    AutoType *VisitAutoType(const AutoType *AT) {
+      return const_cast<AutoType*>(AT);
+    }
+
+    // Only these types can contain the desired 'auto' type.
+    AutoType *VisitPointerType(const PointerType *T) {
+      return Visit(T->getPointeeType());
+    }
+    AutoType *VisitBlockPointerType(const BlockPointerType *T) {
+      return Visit(T->getPointeeType());
+    }
+    AutoType *VisitReferenceType(const ReferenceType *T) {
+      return Visit(T->getPointeeTypeAsWritten());
+    }
+    AutoType *VisitMemberPointerType(const MemberPointerType *T) {
+      return Visit(T->getPointeeType());
+    }
+    AutoType *VisitArrayType(const ArrayType *T) {
+      return Visit(T->getElementType());
+    }
+    AutoType *VisitDependentSizedExtVectorType(
+      const DependentSizedExtVectorType *T) {
+      return Visit(T->getElementType());
+    }
+    AutoType *VisitVectorType(const VectorType *T) {
+      return Visit(T->getElementType());
+    }
+    AutoType *VisitFunctionType(const FunctionType *T) {
+      return Visit(T->getResultType());
+    }
+    AutoType *VisitParenType(const ParenType *T) {
+      return Visit(T->getInnerType());
+    }
+    AutoType *VisitAttributedType(const AttributedType *T) {
+      return Visit(T->getModifiedType());
+    }
+  };
+}
+
+AutoType *Type::getContainedAutoType() const {
+  return GetContainedAutoVisitor().Visit(this);
+}
+
 bool Type::isIntegerType() const {
   if (const BuiltinType *BT = dyn_cast<BuiltinType>(CanonicalType))
     return BT->getKind() >= BuiltinType::Bool &&
@@ -1066,7 +1121,6 @@ const char *BuiltinType::getName(const LangOptions &LO) const {
   case NullPtr:           return "nullptr_t";
   case Overload:          return "<overloaded function type>";
   case Dependent:         return "<dependent type>";
-  case UndeducedAuto:     return "auto";
   case ObjCId:            return "id";
   case ObjCClass:         return "Class";
   case ObjCSel:           return "SEL";
diff --git a/lib/AST/TypeLoc.cpp b/lib/AST/TypeLoc.cpp
index 0680acb1c5..14db7f83c2 100644
--- a/lib/AST/TypeLoc.cpp
+++ b/lib/AST/TypeLoc.cpp
@@ -191,9 +191,7 @@ TypeSpecifierType BuiltinTypeLoc::getWrittenTypeSpec() const {
     case BuiltinType::WChar_S:
     case BuiltinType::WChar_U:
       return TST_wchar;
-    case BuiltinType::UndeducedAuto:
-      return TST_auto;
-        
+
     case BuiltinType::UChar:
     case BuiltinType::UShort:
     case BuiltinType::UInt:
diff --git a/lib/AST/TypePrinter.cpp b/lib/AST/TypePrinter.cpp
index 5e6046acdc..139073987a 100644
--- a/lib/AST/TypePrinter.cpp
+++ b/lib/AST/TypePrinter.cpp
@@ -80,6 +80,8 @@ void TypePrinter::print(const Type *T, Qualifiers Quals, std::string &buffer) {
   bool CanPrefixQualifiers = false;
   
   Type::TypeClass TC = T->getTypeClass();
+  if (const AutoType *AT = dyn_cast<AutoType>(T))
+    TC = AT->desugar()->getTypeClass();
   if (const SubstTemplateTypeParmType *Subst
                                       = dyn_cast<SubstTemplateTypeParmType>(T))
     TC = Subst->getReplacementType()->getTypeClass();
@@ -129,6 +131,7 @@ void TypePrinter::print(const Type *T, Qualifiers Quals, std::string &buffer) {
     case Type::Attributed:
     case Type::PackExpansion:
     case Type::SubstTemplateTypeParm:
+    case Type::Auto:
       CanPrefixQualifiers = false;
       break;
   }
@@ -493,6 +496,17 @@ void TypePrinter::printDecltype(const DecltypeType *T, std::string &S) {
   S = "decltype(" + s.str() + ")" + S;
 }
 
+void TypePrinter::printAuto(const AutoType *T, std::string &S) { 
+  // If the type has been deduced, do not print 'auto'.
+  if (T->isDeduced()) {
+    print(T->getDeducedType(), S);
+  } else {
+    if (!S.empty())    // Prefix the basic type, e.g. 'auto X'.
+      S = ' ' + S;
+    S = "auto" + S;
+  }
+}
+
 /// Appends the given scope to the end of a string.
 void TypePrinter::AppendScope(DeclContext *DC, std::string &Buffer) {
   if (DC->isTranslationUnit()) return;