From: John McCall <rjmccall@apple.com>
Date: Fri, 26 Aug 2011 07:31:35 +0000 (+0000)
Subject: Since the 'is aliased' bit is critical for correctness in C++, it
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=4418439220a8f8e0b1deffdccce2354854c702f5;p=clang

Since the 'is aliased' bit is critical for correctness in C++, it
really shouldn't be optional.  Fix the remaining place where a
temporary was being passed as potentially-aliased memory.

Fixes PR10756.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138627 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGExprAgg.cpp b/lib/CodeGen/CGExprAgg.cpp
index c42c87b1ac..632e016f0e 100644
--- a/lib/CodeGen/CGExprAgg.cpp
+++ b/lib/CodeGen/CGExprAgg.cpp
@@ -444,7 +444,8 @@ void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
         LValue RHS = CGF.EmitLValue(E->getRHS());
         LValue LHS = CGF.EmitLValue(E->getLHS());
         Dest = AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
-                                       needsGC(E->getLHS()->getType()));
+                                       needsGC(E->getLHS()->getType()),
+                                       AggValueSlot::IsAliased);
         EmitFinalDestCopy(E, RHS, true);
         return;
       }
@@ -469,7 +470,8 @@ void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
     // Codegen the RHS so that it stores directly into the LHS.
     AggValueSlot LHSSlot =
       AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed, 
-                              needsGC(E->getLHS()->getType()));
+                              needsGC(E->getLHS()->getType()),
+                              AggValueSlot::IsAliased);
     CGF.EmitAggExpr(E->getRHS(), LHSSlot, false);
     EmitFinalDestCopy(E, LHS, true);
   }
@@ -1052,7 +1054,8 @@ LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
   llvm::Value *Temp = CreateMemTemp(E->getType());
   LValue LV = MakeAddrLValue(Temp, E->getType());
   EmitAggExpr(E, AggValueSlot::forLValue(LV, AggValueSlot::IsNotDestructed,
-                                         AggValueSlot::DoesNotNeedGCBarriers));
+                                         AggValueSlot::DoesNotNeedGCBarriers,
+                                         AggValueSlot::IsNotAliased));
   return LV;
 }
 
diff --git a/lib/CodeGen/CGExprCXX.cpp b/lib/CodeGen/CGExprCXX.cpp
index cdab82eaab..b638e5ba0d 100644
--- a/lib/CodeGen/CGExprCXX.cpp
+++ b/lib/CodeGen/CGExprCXX.cpp
@@ -705,7 +705,8 @@ static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const CXXNewExpr *E,
     AggValueSlot Slot
       = AggValueSlot::forAddr(NewPtr, AllocType.getQualifiers(),
                               AggValueSlot::IsDestructed,
-                              AggValueSlot::DoesNotNeedGCBarriers);
+                              AggValueSlot::DoesNotNeedGCBarriers,
+                              AggValueSlot::IsNotAliased);
     CGF.EmitAggExpr(Init, Slot);
   }
 }
diff --git a/lib/CodeGen/CGValue.h b/lib/CodeGen/CGValue.h
index c448949d13..36b318fb2f 100644
--- a/lib/CodeGen/CGValue.h
+++ b/lib/CodeGen/CGValue.h
@@ -383,7 +383,7 @@ public:
   static AggValueSlot forAddr(llvm::Value *addr, Qualifiers quals,
                               IsDestructed_t isDestructed,
                               NeedsGCBarriers_t needsGC,
-                              IsAliased_t isAliased = IsAliased,
+                              IsAliased_t isAliased,
                               IsZeroed_t isZeroed = IsNotZeroed) {
     AggValueSlot AV;
     AV.Addr = addr;
@@ -397,7 +397,7 @@ public:
 
   static AggValueSlot forLValue(LValue LV, IsDestructed_t isDestructed,
                                 NeedsGCBarriers_t needsGC,
-                                IsAliased_t isAliased = IsAliased,
+                                IsAliased_t isAliased,
                                 IsZeroed_t isZeroed = IsNotZeroed) {
     return forAddr(LV.getAddress(), LV.getQuals(),
                    isDestructed, needsGC, isAliased, isZeroed);
diff --git a/test/CodeGenCXX/conditional-expr-lvalue.cpp b/test/CodeGenCXX/conditional-expr-lvalue.cpp
index a0843c40f0..96aa8b07a6 100644
--- a/test/CodeGenCXX/conditional-expr-lvalue.cpp
+++ b/test/CodeGenCXX/conditional-expr-lvalue.cpp
@@ -5,3 +5,16 @@ void f(bool flag) {
   
   (flag ? a : b) = 3;
 }
+
+// PR10756
+namespace test0 {
+  struct A {
+    A(const A &);
+    A &operator=(const A &);
+    A sub() const;
+    void foo() const;
+  };
+  void foo(bool cond, const A &a) {
+    (cond ? a : a.sub()).foo();
+  }
+}