Order the type traits according to the standard's listing of unary type

traits where possible. For the rest, group them and add some
documentation regarding their origins.

No functionality change intended.

llvm-svn: 130639

clang/lib/Sema/SemaExprCXX.cpp

@@ -2364,22 +2364,82 @@ static bool EvaluateUnaryTypeTrait(Sema &Self, UnaryTypeTrait UTT, QualType T,
   ASTContext &C = Self.Context;
   switch(UTT) {
   default: assert(false && "Unknown type trait or not implemented");
-  case UTT_IsPOD:
+
-    return T->isPODType();
+    // Type trait expressions corresponding to the primary type category
-  case UTT_IsLiteral:
+    // predicates in C++0x [meta.unary.cat].
-    return T->isLiteralType();
+  case UTT_IsVoid:
-  case UTT_IsTrivial:
+    return T->isVoidType();
-    return T->isTrivialType();
+  case UTT_IsIntegral:
-  case UTT_IsClass:
+    return T->isIntegralType(C);
-    if (const RecordType *Record = T->getAs<RecordType>())
+  case UTT_IsFloatingPoint:
-      return !Record->getDecl()->isUnion();
+    return T->isFloatingType();
-    return false;
+  case UTT_IsArray:
+    return T->isArrayType();
+  case UTT_IsPointer:
+    return T->isPointerType();
+  case UTT_IsLvalueReference:
+    return T->isLValueReferenceType();
+  case UTT_IsRvalueReference:
+    return T->isRValueReferenceType();
+  case UTT_IsMemberFunctionPointer:
+    return T->isMemberFunctionPointerType();
+  case UTT_IsMemberObjectPointer:
+    return T->isMemberDataPointerType();
+  case UTT_IsEnum:
+    return T->isEnumeralType();
   case UTT_IsUnion:
     if (const RecordType *Record = T->getAs<RecordType>())
       return Record->getDecl()->isUnion();
     return false;
-  case UTT_IsEnum:
+  case UTT_IsClass:
-    return T->isEnumeralType();
+    if (const RecordType *Record = T->getAs<RecordType>())
+      return !Record->getDecl()->isUnion();
+    return false;
+  case UTT_IsFunction:
+    return T->isFunctionType();
+
+    // Type trait expressions which correspond to the convenient composition
+    // predicates in C++0x [meta.unary.comp].
+  case UTT_IsReference:
+    return T->isReferenceType();
+  case UTT_IsArithmetic:
+    return T->isArithmeticType() && ! T->isEnumeralType();
+  case UTT_IsFundamental:
+    return T->isVoidType() || (T->isArithmeticType() && ! T->isEnumeralType());
+  case UTT_IsObject:
+    // Defined in Section 3.9 p8 of the Working Draft, essentially:
+    // !__is_reference(T) && !__is_function(T) && !__is_void(T).
+    return ! (T->isReferenceType() || T->isFunctionType() || T->isVoidType());
+  case UTT_IsScalar:
+    // Scalar type is defined in Section 3.9 p10 of the Working Draft.
+    // Essentially:
+    // __is_arithmetic( T ) || __is_enumeration(T) ||
+    // __is_pointer(T) || __is_member_pointer(T)
+    return (T->isArithmeticType() || T->isEnumeralType() ||
+            T->isPointerType() || T->isMemberPointerType());
+  case UTT_IsCompound:
+    return ! (T->isVoidType() || T->isArithmeticType()) || T->isEnumeralType();
+  case UTT_IsMemberPointer:
+    return T->isMemberPointerType();
+
+    // Type trait expressions which correspond to the type property predicates
+    // in C++0x [meta.unary.prop].
+  case UTT_IsConst:
+    return T.isConstQualified();
+  case UTT_IsVolatile:
+    return T.isVolatileQualified();
+  case UTT_IsTrivial:
+    return T->isTrivialType();
+  case UTT_IsStandardLayout:
+    return T->isStandardLayoutType();
+  case UTT_IsPOD:
+    return T->isPODType();
+  case UTT_IsLiteral:
+    return T->isLiteralType();
+  case UTT_IsEmpty:
+    if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
+      return !RD->isUnion() && RD->isEmpty();
+    return false;
   case UTT_IsPolymorphic:
     if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
       return RD->isPolymorphic();
@@ -2388,63 +2448,19 @@ static bool EvaluateUnaryTypeTrait(Sema &Self, UnaryTypeTrait UTT, QualType T,
     if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
       return RD->isAbstract();
     return false;
-  case UTT_IsEmpty:
-    if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
-      return !RD->isUnion() && RD->isEmpty();
-    return false;
-  case UTT_IsIntegral:
-    return T->isIntegralType(C);
-  case UTT_IsFloatingPoint:
-    return T->isFloatingType();
-  case UTT_IsArithmetic:
-    return T->isArithmeticType() && ! T->isEnumeralType();
-  case UTT_IsArray:
-    return T->isArrayType();
-  case UTT_IsCompleteType:
-    return !T->isIncompleteType();
-  case UTT_IsCompound:
-    return ! (T->isVoidType() || T->isArithmeticType()) || T->isEnumeralType();
-  case UTT_IsConst:
-    return T.isConstQualified();
-  case UTT_IsFunction:
-    return T->isFunctionType();
-  case UTT_IsFundamental:
-    return T->isVoidType() || (T->isArithmeticType() && ! T->isEnumeralType());
-  case UTT_IsLvalueReference:
-    return T->isLValueReferenceType();
-  case UTT_IsMemberFunctionPointer:
-    return T->isMemberFunctionPointerType();
-  case UTT_IsMemberObjectPointer:
-    return T->isMemberDataPointerType();
-  case UTT_IsMemberPointer:
-    return T->isMemberPointerType();
-  case UTT_IsObject:
-    // Defined in Section 3.9 p8 of the Working Draft, essentially:
-    // !__is_reference(T) && !__is_function(T) && !__is_void(T).
-    return ! (T->isReferenceType() || T->isFunctionType() || T->isVoidType());
-  case UTT_IsPointer:
-    return T->isPointerType();
-  case UTT_IsReference:
-    return T->isReferenceType();
-  case UTT_IsRvalueReference:
-    return T->isRValueReferenceType();
-  case UTT_IsScalar:
-    // Scalar type is defined in Section 3.9 p10 of the Working Draft.
-    // Essentially:
-    // __is_arithmetic( T ) || __is_enumeration(T) ||
-    // __is_pointer(T) || __is_member_pointer(T)
-    return (T->isArithmeticType() || T->isEnumeralType() ||
-            T->isPointerType() || T->isMemberPointerType());
   case UTT_IsSigned:
     return T->isSignedIntegerType();
-  case UTT_IsStandardLayout:
-    return T->isStandardLayoutType();
   case UTT_IsUnsigned:
     return T->isUnsignedIntegerType();
-  case UTT_IsVoid:
+
-    return T->isVoidType();
+    // Type trait expressions which query classes regarding their construction,
-  case UTT_IsVolatile:
+    // destruction, and copying. Rather than being based directly on the
-    return T.isVolatileQualified();
+    // related type predicates in the standard, they are specified by both
+    // GCC[1] and the Embarcadero C++ compiler[2], and Clang implements those
+    // specifications.
+    //
+    //   1: http://gcc.gnu/.org/onlinedocs/gcc/Type-Traits.html
+    //   2: http://docwiki.embarcadero.com/RADStudio/XE/en/Type_Trait_Functions_(C%2B%2B0x)_Index
   case UTT_HasTrivialConstructor:
     // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
     //   If __is_pod (type) is true then the trait is true, else if type is
@@ -2625,6 +2641,15 @@ static bool EvaluateUnaryTypeTrait(Sema &Self, UnaryTypeTrait UTT, QualType T,
         return Destructor->isVirtual();
     }
     return false;
+
+    // These type trait expressions are modeled on the specifications for the
+    // Embarcadero C++0x type trait functions:
+    //   http://docwiki.embarcadero.com/RADStudio/XE/en/Type_Trait_Functions_(C%2B%2B0x)_Index
+  case UTT_IsCompleteType:
+    // http://docwiki.embarcadero.com/RADStudio/XE/en/Is_complete_type_(typename_T_):
+    //   Returns True if and only if T is a complete type at the point of the
+    //   function call.
+    return !T->isIncompleteType();
   }
 }