From: Mike Stump <mrs@apple.com>
Date: Sat, 23 May 2009 22:29:41 +0000 (+0000)
Subject: Track volatile aggregate copies better.  I'm hoping someone else will decide
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=27fe2e6c97a3782a0639d87b460741e8ba5d076d;p=clang

Track volatile aggregate copies better.  I'm hoping someone else will decide
how to get the backend to know that the operation is volatile.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@72348 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGExprAgg.cpp b/lib/CodeGen/CGExprAgg.cpp
index 3b7871390c..b37b7d284e 100644
--- a/lib/CodeGen/CGExprAgg.cpp
+++ b/lib/CodeGen/CGExprAgg.cpp
@@ -144,7 +144,8 @@ void AggExprEmitter::EmitFinalDestCopy(const Expr *E, RValue Src) {
   // FIXME: Pass VolatileDest as well.  I think we also need to merge volatile
   // from the source as well, as we can't eliminate it if either operand
   // is volatile, unless copy has volatile for both source and destination..
-  CGF.EmitAggregateCopy(DestPtr, Src.getAggregateAddr(), E->getType());
+  CGF.EmitAggregateCopy(DestPtr, Src.getAggregateAddr(), E->getType(),
+                        VolatileDest|Src.isVolatileQualified());
 }
 
 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
@@ -484,7 +485,8 @@ void CodeGenFunction::EmitAggregateClear(llvm::Value *DestPtr, QualType Ty) {
 }
 
 void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr,
-                                        llvm::Value *SrcPtr, QualType Ty) {
+                                        llvm::Value *SrcPtr, QualType Ty,
+                                        bool isVolatile) {
   assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
   
   // Aggregate assignment turns into llvm.memcpy.  This is almost valid per
@@ -520,7 +522,8 @@ void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr,
   // }
   //
   // either, we need to use a differnt call here, or the backend needs to be
-  // taught to not do this.
+  // taught to not do this.  We use isVolatile to indicate when either the
+  // source or the destination is volatile.
   Builder.CreateCall4(CGM.getMemCpyFn(),
                       DestPtr, SrcPtr,
                       // TypeInfo.first describes size in bits.
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index 130bc369e3..9a9ca05768 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -419,8 +419,12 @@ public:
   RValue EmitAnyExprToTemp(const Expr *E, llvm::Value *AggLoc = 0,
                            bool isAggLocVolatile = false);
 
+  /// EmitAggregateCopy - Emit an aggrate copy.
+  ///
+  /// \param isVolatile - True iff either the source or the destination is
+  /// volatile.
   void EmitAggregateCopy(llvm::Value *DestPtr, llvm::Value *SrcPtr,
-                         QualType EltTy);
+                         QualType EltTy, bool isVolatile=false);
 
   void EmitAggregateClear(llvm::Value *DestPtr, QualType Ty);