MSVC 2013 type trait support

Implement type trait primitives used in the latest edition of the Microsoft
standard C++ library type_traits header.

With this change we can parse much of the Visual Studio 2013 standard headers,
particularly anything that includes <type_traits>.

Fully implemented, available in all language modes:

 * __is_constructible()
 * __is_nothrow_constructible()
 * __is_nothrow_assignable()

Partially implemented, semantic analysis WIP, available as MS extensions:

 * __is_destructible()
 * __is_nothrow_destructible()

llvm-svn: 199619

1 files changed, 47 insertions, 19 deletions

diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index f9a3acc93f4..a7723d4b263 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -3156,6 +3156,8 @@ static bool CheckUnaryTypeTraitTypeCompleteness(Sema &S, TypeTrait UTT,
   case UTT_IsPolymorphic:
   case UTT_IsAbstract:
   case UTT_IsInterfaceClass:
+  case UTT_IsDestructible:
+  case UTT_IsNothrowDestructible:
     // Fall-through
 
   // These traits require a complete type.
@@ -3219,7 +3221,7 @@ static bool HasNoThrowOperator(const RecordType *RT, OverloadedOperatorKind Op,
         const FunctionProtoType *CPT =
           Operator->getType()->getAs<FunctionProtoType>();
         CPT = Self.ResolveExceptionSpec(KeyLoc, CPT);
-        if (!CPT || !CPT->isNothrow(Self.Context))
+        if (!CPT || !CPT->isNothrow(C))
           return false;
       }
     }
@@ -3421,8 +3423,12 @@ static bool EvaluateUnaryTypeTrait(Sema &Self, TypeTrait UTT,
       return RD->hasTrivialCopyAssignment() &&
              !RD->hasNonTrivialCopyAssignment();
     return false;
+  case UTT_IsDestructible:
+  case UTT_IsNothrowDestructible:
+    // FIXME: Implement UTT_IsDestructible and UTT_IsNothrowDestructible.
+    // For now, let's fall through.
   case UTT_HasTrivialDestructor:
-    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
+    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html
     //   If __is_pod (type) is true or type is a reference type
     //   then the trait is true, else if type is a cv class or union
     //   type (or array thereof) with a trivial destructor
@@ -3505,7 +3511,7 @@ static bool EvaluateUnaryTypeTrait(Sema &Self, TypeTrait UTT,
           CPT = Self.ResolveExceptionSpec(KeyLoc, CPT);
           if (!CPT)
             return false;
-          // FIXME: check whether evaluating default arguments can throw.
+          // TODO: check whether evaluating default arguments can throw.
           // For now, we'll be conservative and assume that they can throw.
           if (!CPT->isNothrow(Self.Context) || CPT->getNumArgs() > 1)
             return false;
@@ -3605,6 +3611,8 @@ static bool evaluateTypeTrait(Sema &S, TypeTrait Kind, SourceLocation KWLoc,
                                    Args[1]->getType(), RParenLoc);
 
   switch (Kind) {
+  case clang::TT_IsConstructible:
+  case clang::TT_IsNothrowConstructible:
   case clang::TT_IsTriviallyConstructible: {
     // C++11 [meta.unary.prop]:
     //   is_trivially_constructible is defined as:
@@ -3663,20 +3671,31 @@ static bool evaluateTypeTrait(Sema &S, TypeTrait Kind, SourceLocation KWLoc,
     InitializationSequence Init(S, To, InitKind, ArgExprs);
     if (Init.Failed())
       return false;
-    
+
     ExprResult Result = Init.Perform(S, To, InitKind, ArgExprs);
     if (Result.isInvalid() || SFINAE.hasErrorOccurred())
       return false;
 
-    // Under Objective-C ARC, if the destination has non-trivial Objective-C
-    // lifetime, this is a non-trivial construction.
-    if (S.getLangOpts().ObjCAutoRefCount &&
-        hasNontrivialObjCLifetime(Args[0]->getType().getNonReferenceType()))
-      return false;
+    if (Kind == clang::TT_IsConstructible)
+      return true;
+
+    if (Kind == clang::TT_IsNothrowConstructible)
+      return S.canThrow(Result.get()) == CT_Cannot;
 
-    // The initialization succeeded; now make sure there are no non-trivial
-    // calls.
-    return !Result.get()->hasNonTrivialCall(S.Context);
+    if (Kind == clang::TT_IsTriviallyConstructible) {
+      // Under Objective-C ARC, if the destination has non-trivial Objective-C
+      // lifetime, this is a non-trivial construction.
+      if (S.getLangOpts().ObjCAutoRefCount &&
+          hasNontrivialObjCLifetime(Args[0]->getType().getNonReferenceType()))
+        return false;
+
+      // The initialization succeeded; now make sure there are no non-trivial
+      // calls.
+      return !Result.get()->hasNonTrivialCall(S.Context);
+    }
+
+    llvm_unreachable("unhandled type trait");
+    return false;
   }
     default: llvm_unreachable("not a TT");
   }
@@ -3831,7 +3850,8 @@ static bool EvaluateBinaryTypeTrait(Sema &Self, TypeTrait BTT, QualType LhsT,
     ExprResult Result = Init.Perform(Self, To, Kind, FromPtr);
     return !Result.isInvalid() && !SFINAE.hasErrorOccurred();
   }
-      
+
+  case BTT_IsNothrowAssignable:
   case BTT_IsTriviallyAssignable: {
     // C++11 [meta.unary.prop]p3:
     //   is_trivially_assignable is defined as:
@@ -3877,13 +3897,21 @@ static bool EvaluateBinaryTypeTrait(Sema &Self, TypeTrait BTT, QualType LhsT,
     if (Result.isInvalid() || SFINAE.hasErrorOccurred())
       return false;
 
-    // Under Objective-C ARC, if the destination has non-trivial Objective-C
-    // lifetime, this is a non-trivial assignment.
-    if (Self.getLangOpts().ObjCAutoRefCount &&
-        hasNontrivialObjCLifetime(LhsT.getNonReferenceType()))
-      return false;
+    if (BTT == BTT_IsNothrowAssignable)
+      return Self.canThrow(Result.get()) == CT_Cannot;
 
-    return !Result.get()->hasNonTrivialCall(Self.Context);
+    if (BTT == BTT_IsTriviallyAssignable) {
+      // Under Objective-C ARC, if the destination has non-trivial Objective-C
+      // lifetime, this is a non-trivial assignment.
+      if (Self.getLangOpts().ObjCAutoRefCount &&
+          hasNontrivialObjCLifetime(LhsT.getNonReferenceType()))
+        return false;
+
+      return !Result.get()->hasNonTrivialCall(Self.Context);
+    }
+
+    llvm_unreachable("unhandled type trait");
+    return false;
   }
     default: llvm_unreachable("not a BTT");
   }