Implement template instantiation for pointer, reference, and (some)
array types. Semantic checking for the construction of these types has
been factored out of GetTypeForDeclarator and into separate
subroutines (BuildPointerType, BuildReferenceType,
BuildArrayType). We'll be doing the same thing for all other types
(and declarations and expressions).

As part of this, moved the type-instantiation functions into a class
in an anonymous namespace. 



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@65663 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaType.cpp b/lib/Sema/SemaType.cpp
index a1c5dbc..bc2bce3 100644
--- a/lib/Sema/SemaType.cpp
+++ b/lib/Sema/SemaType.cpp
@@ -260,6 +260,215 @@
   return Result;
 }
 
+static std::string getPrintableNameForEntity(DeclarationName Entity) {
+  if (Entity)
+    return Entity.getAsString();
+  
+  return "type name";
+}
+
+/// \brief Build a pointer type.
+///
+/// \param T The type to which we'll be building a pointer.
+///
+/// \param Quals The cvr-qualifiers to be applied to the pointer type.
+///
+/// \param Loc The location of the entity whose type involves this
+/// pointer type or, if there is no such entity, the location of the
+/// type that will have pointer type.
+///
+/// \param Entity The name of the entity that involves the pointer
+/// type, if known.
+///
+/// \returns A suitable pointer type, if there are no
+/// errors. Otherwise, returns a NULL type.
+QualType Sema::BuildPointerType(QualType T, unsigned Quals, 
+                                SourceLocation Loc, DeclarationName Entity) {
+  if (T->isReferenceType()) {
+    // C++ 8.3.2p4: There shall be no ... pointers to references ...
+    Diag(Loc, diag::err_illegal_decl_pointer_to_reference)
+      << getPrintableNameForEntity(Entity);
+    return QualType();
+  }
+
+  // Enforce C99 6.7.3p2: "Types other than pointer types derived from
+  // object or incomplete types shall not be restrict-qualified."
+  if ((Quals & QualType::Restrict) && !T->isIncompleteOrObjectType()) {
+    Diag(Loc, diag::err_typecheck_invalid_restrict_invalid_pointee)
+      << T;
+    Quals &= ~QualType::Restrict;
+  }
+
+  // Build the pointer type.
+  return Context.getPointerType(T).getQualifiedType(Quals);
+}
+
+/// \brief Build a reference type.
+///
+/// \param T The type to which we'll be building a reference.
+///
+/// \param Quals The cvr-qualifiers to be applied to the reference type.
+///
+/// \param Loc The location of the entity whose type involves this
+/// reference type or, if there is no such entity, the location of the
+/// type that will have reference type.
+///
+/// \param Entity The name of the entity that involves the reference
+/// type, if known.
+///
+/// \returns A suitable reference type, if there are no
+/// errors. Otherwise, returns a NULL type.
+QualType Sema::BuildReferenceType(QualType T, unsigned Quals, 
+                                  SourceLocation Loc, DeclarationName Entity) {
+  if (T->isReferenceType()) {
+    // C++ [dcl.ref]p4: There shall be no references to references.
+    // 
+    // According to C++ DR 106, references to references are only
+    // diagnosed when they are written directly (e.g., "int & &"),
+    // but not when they happen via a typedef:
+    //
+    //   typedef int& intref;
+    //   typedef intref& intref2;
+    //
+    // Parser::ParserDeclaratorInternal diagnoses the case where
+    // references are written directly; here, we handle the
+    // collapsing of references-to-references as described in C++
+    // DR 106 and amended by C++ DR 540.
+    return T;
+  }
+
+  // C++ [dcl.ref]p1:
+  //   A declarator that specifies the type “reference to cv void”
+  //   is ill-formed.
+  if (T->isVoidType()) {
+    Diag(Loc, diag::err_reference_to_void);
+    return QualType();
+  }
+
+  // Enforce C99 6.7.3p2: "Types other than pointer types derived from
+  // object or incomplete types shall not be restrict-qualified."
+  if ((Quals & QualType::Restrict) && !T->isIncompleteOrObjectType()) {
+    Diag(Loc, diag::err_typecheck_invalid_restrict_invalid_pointee)
+      << T;
+    Quals &= ~QualType::Restrict;
+  }
+
+  // C++ [dcl.ref]p1:
+  //   [...] Cv-qualified references are ill-formed except when the
+  //   cv-qualifiers are introduced through the use of a typedef
+  //   (7.1.3) or of a template type argument (14.3), in which case
+  //   the cv-qualifiers are ignored.
+  //
+  // We diagnose extraneous cv-qualifiers for the non-typedef,
+  // non-template type argument case within the parser. Here, we just
+  // ignore any extraneous cv-qualifiers.
+  Quals &= ~QualType::Const;
+  Quals &= ~QualType::Volatile;
+
+  // Handle restrict on references.
+  return Context.getReferenceType(T).getQualifiedType(Quals);
+}
+
+/// \brief Build an array type.
+///
+/// \param T The type of each element in the array.
+///
+/// \param ASM C99 array size modifier (e.g., '*', 'static').
+///  
+/// \param ArraySize Expression describing the size of the array. 
+///
+/// \param Quals The cvr-qualifiers to be applied to the array's
+/// element type.
+///
+/// \param Loc The location of the entity whose type involves this
+/// array type or, if there is no such entity, the location of the
+/// type that will have array type.
+///
+/// \param Entity The name of the entity that involves the array
+/// type, if known.
+///
+/// \returns A suitable array type, if there are no errors. Otherwise,
+/// returns a NULL type.
+QualType Sema::BuildArrayType(QualType T, ArrayType::ArraySizeModifier ASM,
+                              Expr *ArraySize, unsigned Quals,
+                              SourceLocation Loc, DeclarationName Entity) {
+  // C99 6.7.5.2p1: If the element type is an incomplete or function type, 
+  // reject it (e.g. void ary[7], struct foo ary[7], void ary[7]())
+  if (DiagnoseIncompleteType(Loc, T, 
+                             diag::err_illegal_decl_array_incomplete_type))
+    return QualType();
+
+  if (T->isFunctionType()) {
+    Diag(Loc, diag::err_illegal_decl_array_of_functions)
+      << getPrintableNameForEntity(Entity);
+    return QualType();
+  }
+    
+  // C++ 8.3.2p4: There shall be no ... arrays of references ...
+  if (T->isReferenceType()) {
+    Diag(Loc, diag::err_illegal_decl_array_of_references)
+      << getPrintableNameForEntity(Entity);
+    return QualType();
+  } 
+
+  if (const RecordType *EltTy = T->getAsRecordType()) {
+    // If the element type is a struct or union that contains a variadic
+    // array, accept it as a GNU extension: C99 6.7.2.1p2.
+    if (EltTy->getDecl()->hasFlexibleArrayMember())
+      Diag(Loc, diag::ext_flexible_array_in_array) << T;
+  } else if (T->isObjCInterfaceType()) {
+    Diag(Loc, diag::warn_objc_array_of_interfaces) << T;
+  }
+      
+  // C99 6.7.5.2p1: The size expression shall have integer type.
+  if (ArraySize && !ArraySize->isTypeDependent() &&
+      !ArraySize->getType()->isIntegerType()) {
+    Diag(ArraySize->getLocStart(), diag::err_array_size_non_int)
+      << ArraySize->getType() << ArraySize->getSourceRange();
+    ArraySize->Destroy(Context);
+    return QualType();
+  }
+  llvm::APSInt ConstVal(32);
+  if (!ArraySize) {
+    T = Context.getIncompleteArrayType(T, ASM, Quals);
+  } else if (ArraySize->isValueDependent()) {
+    T = Context.getDependentSizedArrayType(T, ArraySize, ASM, Quals);
+  } else if (!ArraySize->isIntegerConstantExpr(ConstVal, Context) ||
+             (!T->isDependentType() && !T->isConstantSizeType())) {
+    // Per C99, a variable array is an array with either a non-constant
+    // size or an element type that has a non-constant-size
+    T = Context.getVariableArrayType(T, ArraySize, ASM, Quals);
+  } else {
+    // C99 6.7.5.2p1: If the expression is a constant expression, it shall
+    // have a value greater than zero.
+    if (ConstVal.isSigned()) {
+      if (ConstVal.isNegative()) {
+        Diag(ArraySize->getLocStart(),
+             diag::err_typecheck_negative_array_size)
+          << ArraySize->getSourceRange();
+        return QualType();
+      } else if (ConstVal == 0) {
+        // GCC accepts zero sized static arrays.
+        Diag(ArraySize->getLocStart(), diag::ext_typecheck_zero_array_size)
+          << ArraySize->getSourceRange();
+      }
+    } 
+    T = Context.getConstantArrayType(T, ConstVal, ASM, Quals);
+  }
+  // If this is not C99, extwarn about VLA's and C99 array size modifiers.
+  if (!getLangOptions().C99) {
+    if (ArraySize && !ArraySize->isTypeDependent() && 
+        !ArraySize->isValueDependent() && 
+        !ArraySize->isIntegerConstantExpr(Context))
+      Diag(Loc, diag::ext_vla);
+    else if (ASM != ArrayType::Normal || Quals != 0)
+      Diag(Loc, diag::ext_c99_array_usage);
+  }
+
+  return T;
+}
+                              
+
 /// GetTypeForDeclarator - Convert the type for the specified
 /// declarator to Type instances. Skip the outermost Skip type
 /// objects.
@@ -309,6 +518,11 @@
     break;
   }
 
+  // The name we're declaring, if any.
+  DeclarationName Name;
+  if (D.getIdentifier())
+    Name = D.getIdentifier();
+
   // Walk the DeclTypeInfo, building the recursive type as we go.
   // DeclTypeInfos are ordered from the identifier out, which is
   // opposite of what we want :).
@@ -325,72 +539,13 @@
         T = Context.getBlockPointerType(T);
       break;
     case DeclaratorChunk::Pointer:
-      if (T->isReferenceType()) {
-        // C++ 8.3.2p4: There shall be no ... pointers to references ...
-        Diag(DeclType.Loc, diag::err_illegal_decl_pointer_to_reference)
-         << (D.getIdentifier() ? D.getIdentifier()->getName() : "type name");
-        D.setInvalidType(true);
-        T = Context.IntTy;
-      }
-
-      // Enforce C99 6.7.3p2: "Types other than pointer types derived from
-      // object or incomplete types shall not be restrict-qualified."
-      if ((DeclType.Ptr.TypeQuals & QualType::Restrict) &&
-          !T->isIncompleteOrObjectType()) {
-        Diag(DeclType.Loc, diag::err_typecheck_invalid_restrict_invalid_pointee)
-          << T;
-        DeclType.Ptr.TypeQuals &= ~QualType::Restrict;
-      }
-
-      // Apply the pointer typequals to the pointer object.
-      T = Context.getPointerType(T).getQualifiedType(DeclType.Ptr.TypeQuals);
+      T = BuildPointerType(T, DeclType.Ptr.TypeQuals, DeclType.Loc, Name);
       break;
-    case DeclaratorChunk::Reference: {
-      // Whether we should suppress the creation of the reference.
-      bool SuppressReference = false;
-      if (T->isReferenceType()) {
-        // C++ [dcl.ref]p4: There shall be no references to references.
-        // 
-        // According to C++ DR 106, references to references are only
-        // diagnosed when they are written directly (e.g., "int & &"),
-        // but not when they happen via a typedef:
-        //
-        //   typedef int& intref;
-        //   typedef intref& intref2;
-        //
-        // Parser::ParserDeclaratorInternal diagnoses the case where
-        // references are written directly; here, we handle the
-        // collapsing of references-to-references as described in C++
-        // DR 106 and amended by C++ DR 540.
-        SuppressReference = true;
-      }
-
-      // C++ [dcl.ref]p1:
-      //   A declarator that specifies the type “reference to cv void”
-      //   is ill-formed.
-      if (T->isVoidType()) {
-        Diag(DeclType.Loc, diag::err_reference_to_void);
-        D.setInvalidType(true);
-        T = Context.IntTy;
-      }
-
-      // Enforce C99 6.7.3p2: "Types other than pointer types derived from
-      // object or incomplete types shall not be restrict-qualified."
-      if (DeclType.Ref.HasRestrict &&
-          !T->isIncompleteOrObjectType()) {
-        Diag(DeclType.Loc, diag::err_typecheck_invalid_restrict_invalid_pointee)
-          << T;
-        DeclType.Ref.HasRestrict = false;
-      }        
-
-      if (!SuppressReference)
-        T = Context.getReferenceType(T);
-
-      // Handle restrict on references.
-      if (DeclType.Ref.HasRestrict)
-        T.addRestrict();
+    case DeclaratorChunk::Reference:
+      T = BuildReferenceType(T, 
+                             DeclType.Ref.HasRestrict? QualType::Restrict : 0,
+                             DeclType.Loc, Name);
       break;
-    }
     case DeclaratorChunk::Array: {
       DeclaratorChunk::ArrayTypeInfo &ATI = DeclType.Arr;
       Expr *ArraySize = static_cast<Expr*>(ATI.NumElts);
@@ -401,76 +556,7 @@
         ASM = ArrayType::Static;
       else
         ASM = ArrayType::Normal;
-
-      // C99 6.7.5.2p1: If the element type is an incomplete or function type, 
-      // reject it (e.g. void ary[7], struct foo ary[7], void ary[7]())
-      if (DiagnoseIncompleteType(D.getIdentifierLoc(), T, 
-                                 diag::err_illegal_decl_array_incomplete_type)) {
-        T = Context.IntTy;
-        D.setInvalidType(true);
-      } else if (T->isFunctionType()) {
-        Diag(D.getIdentifierLoc(), diag::err_illegal_decl_array_of_functions)
-          << (D.getIdentifier() ? D.getIdentifier()->getName() : "type name");
-        T = Context.getPointerType(T);
-        D.setInvalidType(true);
-      } else if (const ReferenceType *RT = T->getAsReferenceType()) {
-        // C++ 8.3.2p4: There shall be no ... arrays of references ...
-        Diag(D.getIdentifierLoc(), diag::err_illegal_decl_array_of_references)
-          << (D.getIdentifier() ? D.getIdentifier()->getName() : "type name");
-        T = RT->getPointeeType();
-        D.setInvalidType(true);
-      } else if (const RecordType *EltTy = T->getAsRecordType()) {
-        // If the element type is a struct or union that contains a variadic
-        // array, accept it as a GNU extension: C99 6.7.2.1p2.
-        if (EltTy->getDecl()->hasFlexibleArrayMember())
-          Diag(DeclType.Loc, diag::ext_flexible_array_in_array) << T;
-      } else if (T->isObjCInterfaceType()) {
-        Diag(DeclType.Loc, diag::warn_objc_array_of_interfaces) << T;
-      }
-      
-      // C99 6.7.5.2p1: The size expression shall have integer type.
-      if (ArraySize && !ArraySize->getType()->isIntegerType()) {
-        Diag(ArraySize->getLocStart(), diag::err_array_size_non_int)
-          << ArraySize->getType() << ArraySize->getSourceRange();
-        D.setInvalidType(true);
-        ArraySize->Destroy(Context);
-        ATI.NumElts = ArraySize = 0;
-      }
-      llvm::APSInt ConstVal(32);
-      if (!ArraySize) {
-        T = Context.getIncompleteArrayType(T, ASM, ATI.TypeQuals);
-      } else if (ArraySize->isValueDependent()) {
-        T = Context.getDependentSizedArrayType(T, ArraySize, ASM, ATI.TypeQuals);
-      } else if (!ArraySize->isIntegerConstantExpr(ConstVal, Context) ||
-                 !T->isConstantSizeType()) {
-        // Per C99, a variable array is an array with either a non-constant
-        // size or an element type that has a non-constant-size
-        T = Context.getVariableArrayType(T, ArraySize, ASM, ATI.TypeQuals);
-      } else {
-        // C99 6.7.5.2p1: If the expression is a constant expression, it shall
-        // have a value greater than zero.
-        if (ConstVal.isSigned()) {
-          if (ConstVal.isNegative()) {
-            Diag(ArraySize->getLocStart(),
-                 diag::err_typecheck_negative_array_size)
-              << ArraySize->getSourceRange();
-            D.setInvalidType(true);
-          } else if (ConstVal == 0) {
-            // GCC accepts zero sized static arrays.
-            Diag(ArraySize->getLocStart(), diag::ext_typecheck_zero_array_size)
-              << ArraySize->getSourceRange();
-          }
-        } 
-        T = Context.getConstantArrayType(T, ConstVal, ASM, ATI.TypeQuals);
-      }
-      // If this is not C99, extwarn about VLA's and C99 array size modifiers.
-      if (!getLangOptions().C99) {
-        if (ArraySize && !ArraySize->isValueDependent() && 
-            !ArraySize->isIntegerConstantExpr(Context))
-          Diag(D.getIdentifierLoc(), diag::ext_vla);
-        else if (ASM != ArrayType::Normal || ATI.TypeQuals != 0)
-          Diag(D.getIdentifierLoc(), diag::ext_c99_array_usage);
-      }
+      T = BuildArrayType(T, ASM, ArraySize, ATI.TypeQuals, DeclType.Loc, Name);
       break;
     }
     case DeclaratorChunk::Function: {
@@ -632,6 +718,11 @@
       break;
     }
 
+    if (T.isNull()) {
+      D.setInvalidType(true);
+      T = Context.IntTy;
+    }
+
     // See if there are any attributes on this declarator chunk.
     if (const AttributeList *AL = DeclType.getAttrs())
       ProcessTypeAttributeList(T, AL);