Teach the __is_trivially_assignable and __is_trivially_constructible

type traits that assignment to/construction of a lifetime-qualified
object under ARC is *not* trivial. Fixes <rdar://problem/11738725>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@159401 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 33 insertions, 2 deletions

diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 27ac381867..8efd465580 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -3335,6 +3335,25 @@ ExprResult Sema::ActOnBinaryTypeTrait(BinaryTypeTrait BTT,
   return BuildBinaryTypeTrait(BTT, KWLoc, LhsTSInfo, RhsTSInfo, RParen);
 }
 
+/// \brief Determine whether T has a non-trivial Objective-C lifetime in
+/// ARC mode.
+static bool hasNontrivialObjCLifetime(QualType T) {
+  switch (T.getObjCLifetime()) {
+  case Qualifiers::OCL_ExplicitNone:
+    return false;
+
+  case Qualifiers::OCL_Strong:
+  case Qualifiers::OCL_Weak:
+  case Qualifiers::OCL_Autoreleasing:
+    return true;
+
+  case Qualifiers::OCL_None:
+    return T->isObjCLifetimeType();
+  }
+
+  llvm_unreachable("Unknown ObjC lifetime qualifier");
+}
+
 static bool evaluateTypeTrait(Sema &S, TypeTrait Kind, SourceLocation KWLoc,
                               ArrayRef<TypeSourceInfo *> Args,
                               SourceLocation RParenLoc) {
@@ -3408,8 +3427,14 @@ static bool evaluateTypeTrait(Sema &S, TypeTrait Kind, SourceLocation KWLoc,
                                                   ArgExprs.size()));
     if (Result.isInvalid() || SFINAE.hasErrorOccurred())
       return false;
-    
-    // The initialization succeeded; not make sure there are no non-trivial 
+
+    // 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);
   }
@@ -3590,6 +3615,12 @@ static bool EvaluateBinaryTypeTrait(Sema &Self, BinaryTypeTrait BTT,
     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;
+
     return !Result.get()->hasNonTrivialCall(Self.Context);
   }
   }