objective-C arc IR-gen. Retaining of strong

arguments in function prologue is done
with objc_StoreStrong to pair it with
similar objc_StoreStrong for release in function
epilogue. This is done with -O0 only.
// rdar://13145317


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175698 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 17 insertions, 8 deletions

diff --git a/lib/CodeGen/CGDecl.cpp b/lib/CodeGen/CGDecl.cpp
index a43a38360b..a4d673b8c3 100644
--- a/lib/CodeGen/CGDecl.cpp
+++ b/lib/CodeGen/CGDecl.cpp
@@ -1526,13 +1526,14 @@ void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg,
     // Otherwise, create a temporary to hold the value.
     llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty),
                                                D.getName() + ".addr");
-    Alloc->setAlignment(getContext().getDeclAlign(&D).getQuantity());
+    CharUnits Align = getContext().getDeclAlign(&D);
+    Alloc->setAlignment(Align.getQuantity());
     DeclPtr = Alloc;
 
     bool doStore = true;
 
     Qualifiers qs = Ty.getQualifiers();
-
+    LValue lv = MakeAddrLValue(DeclPtr, Ty, Align);
     if (Qualifiers::ObjCLifetime lt = qs.getObjCLifetime()) {
       // We honor __attribute__((ns_consumed)) for types with lifetime.
       // For __strong, it's handled by just skipping the initial retain;
@@ -1553,11 +1554,22 @@ void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg,
       }
 
       if (lt == Qualifiers::OCL_Strong) {
-        if (!isConsumed)
+        if (!isConsumed) {
+          if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
+            // use objc_storeStrong(&dest, value) for retaining the
+            // object. But first, store a null into 'dest' because
+            // objc_storeStrong attempts to release its old value.
+            llvm::Value * Null = CGM.EmitNullConstant(D.getType());
+            EmitStoreOfScalar(Null, lv, /* isInitialization */ true);
+            EmitARCStoreStrongCall(lv.getAddress(), Arg, true);
+            doStore = false;
+          }
+          else
           // Don't use objc_retainBlock for block pointers, because we
           // don't want to Block_copy something just because we got it
           // as a parameter.
-          Arg = EmitARCRetainNonBlock(Arg);
+            Arg = EmitARCRetainNonBlock(Arg);
+        }
       } else {
         // Push the cleanup for a consumed parameter.
         if (isConsumed)
@@ -1574,11 +1586,8 @@ void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg,
     }
 
     // Store the initial value into the alloca.
-    if (doStore) {
-      LValue lv = MakeAddrLValue(DeclPtr, Ty,
-                                 getContext().getDeclAlign(&D));
+    if (doStore)
       EmitStoreOfScalar(Arg, lv, /* isInitialization */ true);
-    }
   }
 
   llvm::Value *&DMEntry = LocalDeclMap[&D];