From c9656faf1e73998b0ca0f0aff6652fec69c02c64 Mon Sep 17 00:00:00 2001 From: Michael Gottesman Date: Sat, 12 Jan 2013 01:25:15 +0000 Subject: Fixed a bug where we were tail calling objc_autorelease causing an object to not be placed into an autorelease pool. The reason that this occurs is that tail calling objc_autorelease eventually tail calls -[NSObject autorelease] which supports fast autorelease. This can cause us to violate the semantic gaurantees of __autoreleasing variables that assignment to an __autoreleasing variables always yields an object that is placed into the innermost autorelease pool. The fix included in this patch works by: 1. In the peephole optimization function OptimizeIndividualFunctions, always remove tail call from objc_autorelease. 2. Whenever we convert to/from an objc_autorelease, set/unset the tail call keyword as appropriate. *NOTE* I also handled the case where objc_autorelease is converted in OptimizeReturns to an autoreleaseRV which still violates the ARC semantics. I will be removing that in a later patch and I wanted to make sure that the tree is in a consistent state vis-a-vis ARC always. Additionally some test cases are provided and all tests that have tail call marked objc_autorelease keywords have been modified so that tail call has been removed. *NOTE* One test fails due to a separate bug that I am going to commit soon. Thus I marked the check line TMP: instead of CHECK: so make check does not fail. llvm-svn: 172287 --- llvm/test/Transforms/ObjCARC/move-and-form-retain-autorelease.ll | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'llvm/test/Transforms/ObjCARC/move-and-form-retain-autorelease.ll') diff --git a/llvm/test/Transforms/ObjCARC/move-and-form-retain-autorelease.ll b/llvm/test/Transforms/ObjCARC/move-and-form-retain-autorelease.ll index 170d0a99c98..d7a54ab4308 100644 --- a/llvm/test/Transforms/ObjCARC/move-and-form-retain-autorelease.ll +++ b/llvm/test/Transforms/ObjCARC/move-and-form-retain-autorelease.ll @@ -212,7 +212,7 @@ bb99: ; preds = %bb57 br label %bb104 bb104: ; preds = %bb99, %bb57 - %tmp105 = tail call i8* @objc_autorelease(i8* %tmp72) nounwind + %tmp105 = call i8* @objc_autorelease(i8* %tmp72) nounwind %tmp106 = bitcast i8* %tmp105 to %14* tail call void @objc_release(i8* %tmp85) nounwind %tmp107 = bitcast %18* %tmp47 to i8* -- cgit v1.2.3