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, 22 insertions, 23 deletions

diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index bb0462f963..9c1a3cf249 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -78,35 +78,31 @@ llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
   return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
 }
 
-/// EmitAnyExpr - Emit code to compute the specified expression which can have
-/// any type.  The result is returned as an RValue struct.  If this is an
-/// aggregate expression, the aggloc/agglocvolatile arguments indicate where the
+/// EmitAnyExpr - Emit code to compute the specified expression which
+/// can have any type.  The result is returned as an RValue struct.
+/// If this is an aggregate expression, AggSlot indicates where the
 /// result should be returned.
-RValue CodeGenFunction::EmitAnyExpr(const Expr *E, llvm::Value *AggLoc,
-                                    bool IsAggLocVolatile, bool IgnoreResult,
-                                    bool IsInitializer) {
+RValue CodeGenFunction::EmitAnyExpr(const Expr *E, AggValueSlot AggSlot,
+                                    bool IgnoreResult) {
   if (!hasAggregateLLVMType(E->getType()))
     return RValue::get(EmitScalarExpr(E, IgnoreResult));
   else if (E->getType()->isAnyComplexType())
     return RValue::getComplex(EmitComplexExpr(E, false, false,
                                               IgnoreResult, IgnoreResult));
 
-  EmitAggExpr(E, AggLoc, IsAggLocVolatile, IgnoreResult, IsInitializer);
-  return RValue::getAggregate(AggLoc, IsAggLocVolatile);
+  EmitAggExpr(E, AggSlot, IgnoreResult);
+  return AggSlot.asRValue();
 }
 
 /// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result will
 /// always be accessible even if no aggregate location is provided.
-RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E,
-                                          bool IsAggLocVolatile,
-                                          bool IsInitializer) {
-  llvm::Value *AggLoc = 0;
+RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E) {
+  AggValueSlot AggSlot = AggValueSlot::ignored();
 
   if (hasAggregateLLVMType(E->getType()) &&
       !E->getType()->isAnyComplexType())
-    AggLoc = CreateMemTemp(E->getType(), "agg.tmp");
-  return EmitAnyExpr(E, AggLoc, IsAggLocVolatile, /*IgnoreResult=*/false,
-                     IsInitializer);
+    AggSlot = CreateAggTemp(E->getType(), "agg.tmp");
+  return EmitAnyExpr(E, AggSlot);
 }
 
 /// EmitAnyExprToMem - Evaluate an expression into a given memory
@@ -118,7 +114,7 @@ void CodeGenFunction::EmitAnyExprToMem(const Expr *E,
   if (E->getType()->isComplexType())
     EmitComplexExprIntoAddr(E, Location, IsLocationVolatile);
   else if (hasAggregateLLVMType(E->getType()))
-    EmitAggExpr(E, Location, IsLocationVolatile, /*Ignore*/ false, IsInit);
+    EmitAggExpr(E, AggValueSlot::forAddr(Location, IsLocationVolatile, IsInit));
   else {
     RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
     LValue LV = MakeAddrLValue(Location, E->getType());
@@ -247,13 +243,16 @@ EmitExprForReferenceBinding(CodeGenFunction &CGF, const Expr *E,
     }
     
     // Create a reference temporary if necessary.
+    AggValueSlot AggSlot = AggValueSlot::ignored();
     if (CGF.hasAggregateLLVMType(E->getType()) &&
-        !E->getType()->isAnyComplexType())
+        !E->getType()->isAnyComplexType()) {
       ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(), 
                                                     InitializedDecl);
+      AggSlot = AggValueSlot::forAddr(ReferenceTemporary, false,
+                                      InitializedDecl != 0);
+    }
       
-    RV = CGF.EmitAnyExpr(E, ReferenceTemporary, /*IsAggLocVolatile=*/false,
-                         /*IgnoreResult=*/false, InitializedDecl);
+    RV = CGF.EmitAnyExpr(E, AggSlot);
 
     if (InitializedDecl) {
       // Get the destructor for the reference temporary.
@@ -1673,7 +1672,7 @@ LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr *E){
   const Expr *InitExpr = E->getInitializer();
   LValue Result = MakeAddrLValue(DeclPtr, E->getType());
 
-  EmitAnyExprToMem(InitExpr, DeclPtr, /*Volatile*/ false);
+  EmitAnyExprToMem(InitExpr, DeclPtr, /*Volatile*/ false, /*Init*/ true);
 
   return Result;
 }
@@ -1965,9 +1964,9 @@ LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
 }
 
 LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
-  llvm::Value *Temp = CreateMemTemp(E->getType(), "tmp");
-  EmitCXXConstructExpr(Temp, E);
-  return MakeAddrLValue(Temp, E->getType());
+  AggValueSlot Slot = CreateAggTemp(E->getType(), "tmp");
+  EmitCXXConstructExpr(E, Slot);
+  return MakeAddrLValue(Slot.getAddr(), E->getType());
 }
 
 LValue