From 58fb3401fa63174cd37281d167b16d90e84a47be Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Mon, 25 Jun 2012 19:47:37 +0000
Subject: [PATCH] Fix the objc_autoreleasedReturnValue optimization code to
 locate the call correctly even in the case where it is an invoke. This fixes
 rdar://11714057.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159157 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/ObjCARC.cpp             | 19 ++++++++--
 test/Transforms/ObjCARC/contract-testcases.ll | 35 ++++++++++++++++---
 2 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/lib/Transforms/Scalar/ObjCARC.cpp b/lib/Transforms/Scalar/ObjCARC.cpp
index d89996a1ff6..87e17c7f90a 100644
--- a/lib/Transforms/Scalar/ObjCARC.cpp
+++ b/lib/Transforms/Scalar/ObjCARC.cpp
@@ -4064,8 +4064,22 @@ bool ObjCARCContract::runOnFunction(Function &F) {
       if (!RetainRVMarker)
         break;
       BasicBlock::iterator BBI = Inst;
-      --BBI;
-      while (isNoopInstruction(BBI)) --BBI;
+      BasicBlock *InstParent = Inst->getParent();
+
+      // Step up to see if the call immediately precedes the RetainRV call.
+      // If it's an invoke, we have to cross a block boundary. And we have
+      // to carefully dodge no-op instructions.
+      do {
+        if (&*BBI == InstParent->begin()) {
+          BasicBlock *Pred = InstParent->getSinglePredecessor();
+          if (!Pred)
+            goto decline_rv_optimization;
+          BBI = Pred->getTerminator();
+          break;
+        }
+        --BBI;
+      } while (isNoopInstruction(BBI));
+
       if (&*BBI == GetObjCArg(Inst)) {
         Changed = true;
         InlineAsm *IA =
@@ -4075,6 +4089,7 @@ bool ObjCARCContract::runOnFunction(Function &F) {
                          /*Constraints=*/"", /*hasSideEffects=*/true);
         CallInst::Create(IA, "", Inst);
       }
+    decline_rv_optimization:
       break;
     }
     case IC_InitWeak: {
diff --git a/test/Transforms/ObjCARC/contract-testcases.ll b/test/Transforms/ObjCARC/contract-testcases.ll
index 69fa8376757..1510ed00e69 100644
--- a/test/Transforms/ObjCARC/contract-testcases.ll
+++ b/test/Transforms/ObjCARC/contract-testcases.ll
@@ -4,17 +4,17 @@
 %0 = type opaque
 %1 = type opaque
 %2 = type { i64, i64 }
-%3 = type { i8*, i8* }
 %4 = type opaque
 
 declare %0* @"\01-[NSAttributedString(Terminal) pathAtIndex:effectiveRange:]"(%1*, i8* nocapture, i64, %2*) optsize
 declare i8* @objc_retainAutoreleasedReturnValue(i8*)
-declare i8* @objc_msgSend_fixup(i8*, %3*, ...)
+declare i8* @objc_msgSend_fixup(i8*, i8*, ...)
+declare i8* @objc_msgSend(i8*, i8*, ...)
 declare void @objc_release(i8*)
 declare %2 @NSUnionRange(i64, i64, i64, i64) optsize
 declare i8* @objc_autoreleaseReturnValue(i8*)
 declare i8* @objc_autorelease(i8*)
-declare i8* @objc_msgSend() nonlazybind
+declare i32 @__gxx_personality_sj0(...)
 
 ; Don't get in trouble on bugpointed code.
 
@@ -52,7 +52,7 @@ bb6:                                              ; preds = %bb5, %bb4, %bb4, %b
 ; CHECK: %tmp8 = phi %0* [ %0, %bb ], [ %0, %bb ]
 define void @test1() {
 bb:
-  %tmp = tail call %0* bitcast (i8* ()* @objc_msgSend to %0* ()*)()
+  %tmp = tail call %0* bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to %0* ()*)()
   %tmp2 = bitcast %0* %tmp to i8*
   %tmp3 = tail call i8* @objc_retainAutoreleasedReturnValue(i8* %tmp2) nounwind
   br i1 undef, label %bb7, label %bb7
@@ -61,3 +61,30 @@ bb7:                                              ; preds = %bb6, %bb6, %bb5
   %tmp8 = phi %0* [ %tmp, %bb ], [ %tmp, %bb ]
   unreachable
 }
+
+; When looking for the defining instruction for an objc_retainAutoreleasedReturnValue
+; call, handle the case where it's an invoke in a different basic block.
+; rdar://11714057
+
+; CHECK: define void @_Z6doTestP8NSString() {
+; CHECK: invoke.cont:                                      ; preds = %entry
+; CHECK-NEXT: call void asm sideeffect "mov\09r7, r7\09\09@ marker for objc_retainAutoreleaseReturnValue", ""()
+; CHECK-NEXT: %tmp = tail call i8* @objc_retainAutoreleasedReturnValue(i8* %call) nounwind
+define void @_Z6doTestP8NSString() {
+entry:
+  %call = invoke i8* bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to i8* ()*)()
+          to label %invoke.cont unwind label %lpad
+
+invoke.cont:                                      ; preds = %entry
+  %tmp = tail call i8* @objc_retainAutoreleasedReturnValue(i8* %call) nounwind
+  unreachable
+
+lpad:                                             ; preds = %entry
+  %tmp1 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_sj0 to i8*)
+          cleanup
+  resume { i8*, i32 } undef
+}
+
+!clang.arc.retainAutoreleasedReturnValueMarker = !{!0}
+
+!0 = metadata !{metadata !"mov\09r7, r7\09\09@ marker for objc_retainAutoreleaseReturnValue"}