Fix representation of compound literals for C++ objects with destructors.

Previously, this compound literal expression (a GNU extension in C++):

  (AggregateWithDtor){1, 2}

resulted in this AST:

 `-CXXBindTemporaryExpr [...] 'struct Point' (CXXTemporary [...])
   `-CompoundLiteralExpr [...] 'struct AggregateWithDtor'
     `-CXXBindTemporaryExpr [...] 'struct AggregateWithDtor' (CXXTemporary [...])
       `-InitListExpr [...] 'struct AggregateWithDtor'
         |-IntegerLiteral [...] 'int' 1
         `-IntegerLiteral [...] 'int' 2

Note the two CXXBindTemporaryExprs. The InitListExpr is really part of the
CompoundLiteralExpr, not an object in its own right. By introducing a new
entity initialization kind in Sema specifically for compound literals, we
avoid the treatment of the inner InitListExpr as a temporary.

 `-CXXBindTemporaryExpr [...] 'struct Point' (CXXTemporary [...])
   `-CompoundLiteralExpr [...] 'struct AggregateWithDtor'
     `-InitListExpr [...] 'struct AggregateWithDtor'
       |-IntegerLiteral [...] 'int' 1
       `-IntegerLiteral [...] 'int' 2

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181212 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 35 insertions, 6 deletions

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 18c1d8fb32..0c1065813e 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -4509,7 +4509,7 @@ Sema::BuildCompoundLiteralExpr(SourceLocation LParenLoc, TypeSourceInfo *TInfo,
     return ExprError();
 
   InitializedEntity Entity
-    = InitializedEntity::InitializeTemporary(literalType);
+    = InitializedEntity::InitializeCompoundLiteralInit(TInfo);
   InitializationKind Kind
     = InitializationKind::CreateCStyleCast(LParenLoc, 
                                            SourceRange(LParenLoc, RParenLoc),
diff --git a/lib/Sema/SemaInit.cpp b/lib/Sema/SemaInit.cpp
index 993e68bd67..de93adb6be 100644
--- a/lib/Sema/SemaInit.cpp
+++ b/lib/Sema/SemaInit.cpp
@@ -2394,6 +2394,7 @@ DeclarationName InitializedEntity::getName() const {
   case EK_VectorElement:
   case EK_ComplexElement:
   case EK_BlockElement:
+  case EK_CompoundLiteralInit:
     return DeclarationName();
   }
 
@@ -2420,6 +2421,7 @@ DeclaratorDecl *InitializedEntity::getDecl() const {
   case EK_ComplexElement:
   case EK_BlockElement:
   case EK_LambdaCapture:
+  case EK_CompoundLiteralInit:
     return 0;
   }
 
@@ -2437,6 +2439,7 @@ bool InitializedEntity::allowsNRVO() const {
   case EK_Member:
   case EK_New:
   case EK_Temporary:
+  case EK_CompoundLiteralInit:
   case EK_Base:
   case EK_Delegating:
   case EK_ArrayElement:
@@ -4468,6 +4471,7 @@ getAssignmentAction(const InitializedEntity &Entity) {
   case InitializedEntity::EK_ComplexElement:
   case InitializedEntity::EK_BlockElement:
   case InitializedEntity::EK_LambdaCapture:
+  case InitializedEntity::EK_CompoundLiteralInit:
     return Sema::AA_Initializing;
   }
 
@@ -4490,6 +4494,7 @@ static bool shouldBindAsTemporary(const InitializedEntity &Entity) {
   case InitializedEntity::EK_Exception:
   case InitializedEntity::EK_BlockElement:
   case InitializedEntity::EK_LambdaCapture:
+  case InitializedEntity::EK_CompoundLiteralInit:
     return false;
 
   case InitializedEntity::EK_Parameter:
@@ -4520,6 +4525,7 @@ static bool shouldDestroyTemporary(const InitializedEntity &Entity) {
     case InitializedEntity::EK_Temporary:
     case InitializedEntity::EK_ArrayElement:
     case InitializedEntity::EK_Exception:
+    case InitializedEntity::EK_CompoundLiteralInit:
       return true;
   }
 
@@ -4601,6 +4607,7 @@ static SourceLocation getInitializationLoc(const InitializedEntity &Entity,
   case InitializedEntity::EK_VectorElement:
   case InitializedEntity::EK_ComplexElement:
   case InitializedEntity::EK_BlockElement:
+  case InitializedEntity::EK_CompoundLiteralInit:
     return Initializer->getLocStart();
   }
   llvm_unreachable("missed an InitializedEntity kind?");
@@ -4828,6 +4835,31 @@ static bool isReferenceBinding(const InitializationSequence::Step &s) {
          s.Kind == InitializationSequence::SK_BindReferenceToTemporary;
 }
 
+/// Returns true if the parameters describe a constructor initialization of
+/// an explicit temporary object, e.g. "Point(x, y)".
+static bool isExplicitTemporary(const InitializedEntity &Entity,
+                                const InitializationKind &Kind,
+                                unsigned NumArgs) {
+  switch (Entity.getKind()) {
+  case InitializedEntity::EK_Temporary:
+  case InitializedEntity::EK_CompoundLiteralInit:
+    break;
+  default:
+    return false;
+  }
+
+  switch (Kind.getKind()) {
+  case InitializationKind::IK_DirectList:
+    return true;
+  // FIXME: Hack to work around cast weirdness.
+  case InitializationKind::IK_Direct:
+  case InitializationKind::IK_Value:
+    return NumArgs != 1;
+  default:
+    return false;
+  }
+}
+
 static ExprResult
 PerformConstructorInitialization(Sema &S,
                                  const InitializedEntity &Entity,
@@ -4878,11 +4910,7 @@ PerformConstructorInitialization(Sema &S,
     return ExprError();
 
 
-  if (Entity.getKind() == InitializedEntity::EK_Temporary &&
-      (Kind.getKind() == InitializationKind::IK_DirectList ||
-       (NumArgs != 1 && // FIXME: Hack to work around cast weirdness
-        (Kind.getKind() == InitializationKind::IK_Direct ||
-         Kind.getKind() == InitializationKind::IK_Value)))) {
+  if (isExplicitTemporary(Entity, Kind, NumArgs)) {
     // An explicitly-constructed temporary, e.g., X(1, 2).
     S.MarkFunctionReferenced(Loc, Constructor);
     if (S.DiagnoseUseOfDecl(Constructor, Loc))
@@ -4984,6 +5012,7 @@ InitializedEntityOutlivesFullExpression(const InitializedEntity &Entity) {
   case InitializedEntity::EK_Parameter:
   case InitializedEntity::EK_Temporary:
   case InitializedEntity::EK_LambdaCapture:
+  case InitializedEntity::EK_CompoundLiteralInit:
     // The entity being initialized might not outlive the full-expression.
     return false;
   }