Add support for objc_unsafeClaimAutoreleasedReturnValue to the

ObjC ARC Optimizer.

The main implication of this is:

1. Ensuring that we treat it conservatively in terms of optimization.
2. We put the ASM marker on it so that the runtime can recognize
objc_unsafeClaimAutoreleasedReturnValue from releaseRV.

<rdar://problem/21567064>

Patch by Michael Gottesman!

llvm-svn: 258970

1 files changed, 16 insertions, 16 deletions

diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
index 1cdf5689f42..edef360be61 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
@@ -66,7 +66,7 @@ namespace {
 
     /// The inline asm string to insert between calls and RetainRV calls to make
     /// the optimization work on targets which need it.
-    const MDString *RetainRVMarker;
+    const MDString *RVInstMarker;
 
     /// The set of inserted objc_storeStrong calls. If at the end of walking the
     /// function we have found no alloca instructions, these calls can be marked
@@ -423,16 +423,16 @@ bool ObjCARCContract::tryToPeepholeInstruction(
         return false;
       // If we succeed in our optimization, fall through.
       // FALLTHROUGH
-    case ARCInstKind::RetainRV: {
+    case ARCInstKind::RetainRV:
+    case ARCInstKind::ClaimRV: {
       // If we're compiling for a target which needs a special inline-asm
-      // marker to do the retainAutoreleasedReturnValue optimization,
-      // insert it now.
-      if (!RetainRVMarker)
+      // marker to do the return value optimization, insert it now.
+      if (!RVInstMarker)
         return false;
       BasicBlock::iterator BBI = Inst->getIterator();
       BasicBlock *InstParent = Inst->getParent();
 
-      // Step up to see if the call immediately precedes the RetainRV call.
+      // Step up to see if the call immediately precedes the RV call.
       // If it's an invoke, we have to cross a block boundary. And we have
       // to carefully dodge no-op instructions.
       do {
@@ -447,14 +447,14 @@ bool ObjCARCContract::tryToPeepholeInstruction(
       } while (IsNoopInstruction(&*BBI));
 
       if (&*BBI == GetArgRCIdentityRoot(Inst)) {
-        DEBUG(dbgs() << "Adding inline asm marker for "
-                        "retainAutoreleasedReturnValue optimization.\n");
+        DEBUG(dbgs() << "Adding inline asm marker for the return value "
+                        "optimization.\n");
         Changed = true;
-        InlineAsm *IA =
-          InlineAsm::get(FunctionType::get(Type::getVoidTy(Inst->getContext()),
-                                           /*isVarArg=*/false),
-                         RetainRVMarker->getString(),
-                         /*Constraints=*/"", /*hasSideEffects=*/true);
+        InlineAsm *IA = InlineAsm::get(
+            FunctionType::get(Type::getVoidTy(Inst->getContext()),
+                              /*isVarArg=*/false),
+            RVInstMarker->getString(),
+            /*Constraints=*/"", /*hasSideEffects=*/true);
         CallInst::Create(IA, "", Inst);
       }
     decline_rv_optimization:
@@ -650,15 +650,15 @@ bool ObjCARCContract::doInitialization(Module &M) {
 
   EP.init(&M);
 
-  // Initialize RetainRVMarker.
-  RetainRVMarker = nullptr;
+  // Initialize RVInstMarker.
+  RVInstMarker = nullptr;
   if (NamedMDNode *NMD =
           M.getNamedMetadata("clang.arc.retainAutoreleasedReturnValueMarker"))
     if (NMD->getNumOperands() == 1) {
       const MDNode *N = NMD->getOperand(0);
       if (N->getNumOperands() == 1)
         if (const MDString *S = dyn_cast<MDString>(N->getOperand(0)))
-          RetainRVMarker = S;
+          RVInstMarker = S;
     }
 
   return false;