1 files changed, 209 insertions, 8 deletions

diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index db287515ce..76d6f496e6 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -1989,7 +1989,7 @@ Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
   return false;
 }
 
-ExprResult Sema::ActOnUnaryTypeTrait(UnaryTypeTrait OTT,
+ExprResult Sema::ActOnUnaryTypeTrait(UnaryTypeTrait UTT,
                                      SourceLocation KWLoc,
                                      ParsedType Ty,
                                      SourceLocation RParen) {
@@ -1998,10 +1998,210 @@ ExprResult Sema::ActOnUnaryTypeTrait(UnaryTypeTrait OTT,
 
   if (!TSInfo)
     TSInfo = Context.getTrivialTypeSourceInfo(T);
-  return BuildUnaryTypeTrait(OTT, KWLoc, TSInfo, RParen);
+  return BuildUnaryTypeTrait(UTT, KWLoc, TSInfo, RParen);
 }
 
-ExprResult Sema::BuildUnaryTypeTrait(UnaryTypeTrait OTT,
+static bool EvaluateUnaryTypeTrait(Sema &Self, UnaryTypeTrait UTT, QualType T) {
+  assert(!T->isDependentType() &&
+         "Cannot evaluate traits for dependent types.");
+  ASTContext &C = Self.Context;
+  switch(UTT) {
+  default: assert(false && "Unknown type trait or not implemented");
+  case UTT_IsPOD: return T->isPODType();
+  case UTT_IsLiteral: return T->isLiteralType();
+  case UTT_IsClass: // Fallthrough
+  case UTT_IsUnion:
+    if (const RecordType *Record = T->getAs<RecordType>()) {
+      bool Union = Record->getDecl()->isUnion();
+      return UTT == UTT_IsUnion ? Union : !Union;
+    }
+    return false;
+  case UTT_IsEnum: return T->isEnumeralType();
+  case UTT_IsPolymorphic:
+    if (const RecordType *Record = T->getAs<RecordType>()) {
+      // Type traits are only parsed in C++, so we've got CXXRecords.
+      return cast<CXXRecordDecl>(Record->getDecl())->isPolymorphic();
+    }
+    return false;
+  case UTT_IsAbstract:
+    if (const RecordType *RT = T->getAs<RecordType>())
+      return cast<CXXRecordDecl>(RT->getDecl())->isAbstract();
+    return false;
+  case UTT_IsEmpty:
+    if (const RecordType *Record = T->getAs<RecordType>()) {
+      return !Record->getDecl()->isUnion()
+          && cast<CXXRecordDecl>(Record->getDecl())->isEmpty();
+    }
+    return false;
+  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
+    //   a cv class or union type (or array thereof) with a trivial default
+    //   constructor ([class.ctor]) then the trait is true, else it is false.
+    if (T->isPODType())
+      return true;
+    if (const RecordType *RT =
+          C.getBaseElementType(T)->getAs<RecordType>())
+      return cast<CXXRecordDecl>(RT->getDecl())->hasTrivialConstructor();
+    return false;
+  case UTT_HasTrivialCopy:
+    // 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
+    //   with a trivial copy constructor ([class.copy]) then the trait
+    //   is true, else it is false.
+    if (T->isPODType() || T->isReferenceType())
+      return true;
+    if (const RecordType *RT = T->getAs<RecordType>())
+      return cast<CXXRecordDecl>(RT->getDecl())->hasTrivialCopyConstructor();
+    return false;
+  case UTT_HasTrivialAssign:
+    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
+    //   If type is const qualified or is a reference type then the
+    //   trait is false. Otherwise if __is_pod (type) is true then the
+    //   trait is true, else if type is a cv class or union type with
+    //   a trivial copy assignment ([class.copy]) then the trait is
+    //   true, else it is false.
+    // Note: the const and reference restrictions are interesting,
+    // given that const and reference members don't prevent a class
+    // from having a trivial copy assignment operator (but do cause
+    // errors if the copy assignment operator is actually used, q.v.
+    // [class.copy]p12).
+
+    if (C.getBaseElementType(T).isConstQualified())
+      return false;
+    if (T->isPODType())
+      return true;
+    if (const RecordType *RT = T->getAs<RecordType>())
+      return cast<CXXRecordDecl>(RT->getDecl())->hasTrivialCopyAssignment();
+    return false;
+  case UTT_HasTrivialDestructor:
+    // 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
+    //   ([class.dtor]) then the trait is true, else it is
+    //   false.
+    if (T->isPODType() || T->isReferenceType())
+      return true;
+    if (const RecordType *RT =
+          C.getBaseElementType(T)->getAs<RecordType>())
+      return cast<CXXRecordDecl>(RT->getDecl())->hasTrivialDestructor();
+    return false;
+  // TODO: Propagate nothrowness for implicitly declared special members.
+  case UTT_HasNothrowAssign:
+    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
+    //   If type is const qualified or is a reference type then the
+    //   trait is false. Otherwise if __has_trivial_assign (type)
+    //   is true then the trait is true, else if type is a cv class
+    //   or union type with copy assignment operators that are known
+    //   not to throw an exception then the trait is true, else it is
+    //   false.
+    if (C.getBaseElementType(T).isConstQualified())
+      return false;
+    if (T->isReferenceType())
+      return false;
+    if (T->isPODType())
+      return true;
+    if (const RecordType *RT = T->getAs<RecordType>()) {
+      CXXRecordDecl* RD = cast<CXXRecordDecl>(RT->getDecl());
+      if (RD->hasTrivialCopyAssignment())
+        return true;
+
+      bool FoundAssign = false;
+      bool AllNoThrow = true;
+      DeclarationName Name = C.DeclarationNames.getCXXOperatorName(OO_Equal);
+      DeclContext::lookup_const_iterator Op, OpEnd;
+      for (llvm::tie(Op, OpEnd) = RD->lookup(Name);
+           Op != OpEnd; ++Op) {
+        CXXMethodDecl *Operator = cast<CXXMethodDecl>(*Op);
+        if (Operator->isCopyAssignmentOperator()) {
+          FoundAssign = true;
+          const FunctionProtoType *CPT
+              = Operator->getType()->getAs<FunctionProtoType>();
+          if (!CPT->hasEmptyExceptionSpec()) {
+            AllNoThrow = false;
+            break;
+          }
+        }
+      }
+
+      return FoundAssign && AllNoThrow;
+    }
+    return false;
+  case UTT_HasNothrowCopy:
+    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
+    //   If __has_trivial_copy (type) is true then the trait is true, else
+    //   if type is a cv class or union type with copy constructors that are
+    //   known not to throw an exception then the trait is true, else it is
+    //   false.
+    if (T->isPODType() || T->isReferenceType())
+      return true;
+    if (const RecordType *RT = T->getAs<RecordType>()) {
+      CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
+      if (RD->hasTrivialCopyConstructor())
+        return true;
+
+      bool FoundConstructor = false;
+      bool AllNoThrow = true;
+      unsigned FoundTQs;
+      DeclarationName ConstructorName
+          = C.DeclarationNames.getCXXConstructorName(C.getCanonicalType(T));
+      DeclContext::lookup_const_iterator Con, ConEnd;
+      for (llvm::tie(Con, ConEnd) = RD->lookup(ConstructorName);
+           Con != ConEnd; ++Con) {
+        CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(*Con);
+        if (Constructor->isCopyConstructor(FoundTQs)) {
+          FoundConstructor = true;
+          const FunctionProtoType *CPT
+              = Constructor->getType()->getAs<FunctionProtoType>();
+          if (!CPT->hasEmptyExceptionSpec()) {
+            AllNoThrow = false;
+            break;
+          }
+        }
+      }
+
+      return FoundConstructor && AllNoThrow;
+    }
+    return false;
+  case UTT_HasNothrowConstructor:
+    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
+    //   If __has_trivial_constructor (type) is true then the trait is
+    //   true, else if type is a cv class or union type (or array
+    //   thereof) with a default constructor that is known not to
+    //   throw an exception then the trait is true, else it is false.
+    if (T->isPODType())
+      return true;
+    if (const RecordType *RT = C.getBaseElementType(T)->getAs<RecordType>()) {
+      CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
+      if (RD->hasTrivialConstructor())
+        return true;
+
+      if (CXXConstructorDecl *Constructor = RD->getDefaultConstructor()) {
+        const FunctionProtoType *CPT
+            = Constructor->getType()->getAs<FunctionProtoType>();
+        // TODO: check whether evaluating default arguments can throw.
+        // For now, we'll be conservative and assume that they can throw.
+        if (CPT->hasEmptyExceptionSpec() && CPT->getNumArgs() == 0)
+          return true;
+      }
+    }
+    return false;
+  case UTT_HasVirtualDestructor:
+    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
+    //   If type is a class type with a virtual destructor ([class.dtor])
+    //   then the trait is true, else it is false.
+    if (const RecordType *Record = T->getAs<RecordType>()) {
+      CXXRecordDecl *RD = cast<CXXRecordDecl>(Record->getDecl());
+      if (CXXDestructorDecl *Destructor = RD->getDestructor())
+        return Destructor->isVirtual();
+    }
+    return false;
+  }
+}
+
+ExprResult Sema::BuildUnaryTypeTrait(UnaryTypeTrait UTT,
                                      SourceLocation KWLoc,
                                      TypeSourceInfo *TSInfo,
                                      SourceLocation RParen) {
@@ -2010,7 +2210,7 @@ ExprResult Sema::BuildUnaryTypeTrait(UnaryTypeTrait OTT,
   // According to http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html
   // all traits except __is_class, __is_enum and __is_union require a the type
   // to be complete, an array of unknown bound, or void.
-  if (OTT != UTT_IsClass && OTT != UTT_IsEnum && OTT != UTT_IsUnion) {
+  if (UTT != UTT_IsClass && UTT != UTT_IsEnum && UTT != UTT_IsUnion) {
     QualType E = T;
     if (T->isIncompleteArrayType())
       E = Context.getAsArrayType(T)->getElementType();
@@ -2020,10 +2220,11 @@ ExprResult Sema::BuildUnaryTypeTrait(UnaryTypeTrait OTT,
       return ExprError();
   }
 
-  // There is no point in eagerly computing the value. The traits are designed
-  // to be used from type trait templates, so Ty will be a template parameter
-  // 99% of the time.
-  return Owned(new (Context) UnaryTypeTraitExpr(KWLoc, OTT, TSInfo,
+  bool Value = false;
+  if (!T->isDependentType())
+    Value = EvaluateUnaryTypeTrait(*this, UTT, T);
+
+  return Owned(new (Context) UnaryTypeTraitExpr(KWLoc, UTT, TSInfo, Value,
                                                 RParen, Context.BoolTy));
 }