Change the representation of GNU ?: expressions to use a different expression

class and to bind the shared value using OpaqueValueExpr.  This fixes an
unnoticed problem with deserialization of these expressions where the
deserialized form would lose the vital pointer-equality trait;  or rather,
it fixes it because this patch also does the right thing for deserializing
OVEs.

Change OVEs to not be a "temporary object" in the sense that copy elision is
permitted.

This new representation is not totally unawkward to work with, but I think
that's really part and parcel with the semantics we're modelling here.  In
particular, it's much easier to fix things like the copy elision bug and to
make the CFG look right.

I've tried to update the analyzer to deal with this in at least some          
obvious cases, and I think we get a much better CFG out, but the printing
of OpaqueValueExprs probably needs some work.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@125744 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 10 deletions

diff --git a/lib/CodeGen/CGExprAgg.cpp b/lib/CodeGen/CGExprAgg.cpp
index 0b3a617be1..f992dc7c9c 100644
--- a/lib/CodeGen/CGExprAgg.cpp
+++ b/lib/CodeGen/CGExprAgg.cpp
@@ -116,7 +116,7 @@ public:
   }
   void VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E);
 
-  void VisitConditionalOperator(const ConditionalOperator *CO);
+  void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO);
   void VisitChooseExpr(const ChooseExpr *CE);
   void VisitInitListExpr(InitListExpr *E);
   void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
@@ -245,7 +245,7 @@ void AggExprEmitter::EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore) {
 //===----------------------------------------------------------------------===//
 
 void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) {
-  EmitFinalDestCopy(e, CGF.EmitOpaqueValueLValue(e));
+  EmitFinalDestCopy(e, CGF.getOpaqueLValueMapping(e));
 }
 
 void AggExprEmitter::VisitCastExpr(CastExpr *E) {
@@ -419,16 +419,15 @@ void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
   }
 }
 
-void AggExprEmitter::VisitConditionalOperator(const ConditionalOperator *E) {
-  if (!E->getLHS()) {
-    CGF.ErrorUnsupported(E, "conditional operator with missing LHS");
-    return;
-  }
-
+void AggExprEmitter::
+VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
   llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
   llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
   llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
 
+  // Bind the common expression if necessary.
+  CodeGenFunction::OpaqueValueMapping binding(CGF, E);
+
   CodeGenFunction::ConditionalEvaluation eval(CGF);
   CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
 
@@ -437,7 +436,7 @@ void AggExprEmitter::VisitConditionalOperator(const ConditionalOperator *E) {
 
   eval.begin(CGF);
   CGF.EmitBlock(LHSBlock);
-  Visit(E->getLHS());
+  Visit(E->getTrueExpr());
   eval.end(CGF);
 
   assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!");
@@ -451,7 +450,7 @@ void AggExprEmitter::VisitConditionalOperator(const ConditionalOperator *E) {
 
   eval.begin(CGF);
   CGF.EmitBlock(RHSBlock);
-  Visit(E->getRHS());
+  Visit(E->getFalseExpr());
   eval.end(CGF);
 
   CGF.EmitBlock(ContBlock);