one piece of code is responsible for the lifetime of every aggregate

slot.  The easiest way to do that was to bundle up the information
we care about for aggregate slots into a new structure which demands
that its creators at least consider the question.

I could probably be convinced that the ObjC 'needs GC' bit should
be rolled into this structure.
Implement generalized copy elision.  The main obstacle here is that
IR-generation must be much more careful about making sure that exactly



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@113962 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 17 insertions, 19 deletions

diff --git a/lib/CodeGen/CGExprCXX.cpp b/lib/CodeGen/CGExprCXX.cpp
index 10e29d199c..584f6c099b 100644
--- a/lib/CodeGen/CGExprCXX.cpp
+++ b/lib/CodeGen/CGExprCXX.cpp
@@ -219,16 +219,12 @@ CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E,
       LValue LV = EmitLValue(E->getArg(0));
       llvm::Value *This;
       if (LV.isPropertyRef() || LV.isKVCRef()) {
-        llvm::Value *AggLoc  = CreateMemTemp(E->getArg(1)->getType());
-        EmitAggExpr(E->getArg(1), AggLoc, false /*VolatileDest*/);
+        AggValueSlot Slot = CreateAggTemp(E->getArg(1)->getType());
+        EmitAggExpr(E->getArg(1), Slot);
         if (LV.isPropertyRef())
-          EmitObjCPropertySet(LV.getPropertyRefExpr(),
-                              RValue::getAggregate(AggLoc, 
-                                                   false /*VolatileDest*/));
+          EmitObjCPropertySet(LV.getPropertyRefExpr(), Slot.asRValue());
         else
-          EmitObjCPropertySet(LV.getKVCRefExpr(),
-                              RValue::getAggregate(AggLoc, 
-                                                   false /*VolatileDest*/));
+          EmitObjCPropertySet(LV.getKVCRefExpr(), Slot.asRValue());
         return RValue::getAggregate(0, false);
       }
       else
@@ -269,17 +265,16 @@ CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E,
 }
 
 void
-CodeGenFunction::EmitCXXConstructExpr(llvm::Value *Dest,
-                                      const CXXConstructExpr *E) {
-  assert(Dest && "Must have a destination!");
+CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E,
+                                      AggValueSlot Dest) {
+  assert(!Dest.isIgnored() && "Must have a destination!");
   const CXXConstructorDecl *CD = E->getConstructor();
   
   // If we require zero initialization before (or instead of) calling the
   // constructor, as can be the case with a non-user-provided default
   // constructor, emit the zero initialization now.
   if (E->requiresZeroInitialization())
-    EmitNullInitialization(Dest, E->getType());
-
+    EmitNullInitialization(Dest.getAddr(), E->getType());
   
   // If this is a call to a trivial default constructor, do nothing.
   if (CD->isTrivial() && CD->isDefaultConstructor())
@@ -289,8 +284,8 @@ CodeGenFunction::EmitCXXConstructExpr(llvm::Value *Dest,
   // its first argument instead, if in fact that argument is a temporary 
   // object.
   if (getContext().getLangOptions().ElideConstructors && E->isElidable()) {
-    if (const Expr *Arg = E->getArg(0)->getTemporaryObject()) {
-      EmitAggExpr(Arg, Dest, false);
+    if (E->getArg(0)->isTemporaryObject(getContext(), CD->getParent())) {
+      EmitAggExpr(E->getArg(0), Dest);
       return;
     }
   }
@@ -302,7 +297,7 @@ CodeGenFunction::EmitCXXConstructExpr(llvm::Value *Dest,
     const llvm::Type *BasePtr = ConvertType(BaseElementTy);
     BasePtr = llvm::PointerType::getUnqual(BasePtr);
     llvm::Value *BaseAddrPtr =
-      Builder.CreateBitCast(Dest, BasePtr);
+      Builder.CreateBitCast(Dest.getAddr(), BasePtr);
     
     EmitCXXAggrConstructorCall(CD, Array, BaseAddrPtr, 
                                E->arg_begin(), E->arg_end());
@@ -315,7 +310,7 @@ CodeGenFunction::EmitCXXConstructExpr(llvm::Value *Dest,
       E->getConstructionKind() == CXXConstructExpr::CK_VirtualBase;
     
     // Call the constructor.
-    EmitCXXConstructorCall(CD, Type, ForVirtualBase, Dest,
+    EmitCXXConstructorCall(CD, Type, ForVirtualBase, Dest.getAddr(),
                            E->arg_begin(), E->arg_end());
   }
 }
@@ -539,8 +534,11 @@ static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const CXXNewExpr *E,
   else if (AllocType->isAnyComplexType())
     CGF.EmitComplexExprIntoAddr(Init, NewPtr, 
                                 AllocType.isVolatileQualified());
-  else
-    CGF.EmitAggExpr(Init, NewPtr, AllocType.isVolatileQualified());
+  else {
+    AggValueSlot Slot
+      = AggValueSlot::forAddr(NewPtr, AllocType.isVolatileQualified(), true);
+    CGF.EmitAggExpr(Init, Slot);
+  }
 }
 
 void