[llvm] r372352 - [ObjC][ARC] Skip debug instructions when computing the insert point of

[Akira Hatanaka via llvm-commits]

Author: ahatanak
Date: Thu Sep 19 13:58:51 2019
New Revision: 372352

URL: http://llvm.org/viewvc/llvm-project?rev=372352&view=rev
Log:
[ObjC][ARC] Skip debug instructions when computing the insert point of
objc_release calls

This fixes a bug where the presence of debug instructions would cause
ARC optimizer to change the order of retain and release calls.

rdar://problem/55319419

Added:
    llvm/trunk/test/Transforms/ObjCARC/code-motion.ll
Modified:
    llvm/trunk/lib/Transforms/ObjCARC/PtrState.cpp

Modified: llvm/trunk/lib/Transforms/ObjCARC/PtrState.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/ObjCARC/PtrState.cpp?rev=372352&r1=372351&r2=372352&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/ObjCARC/PtrState.cpp (original)
+++ llvm/trunk/lib/Transforms/ObjCARC/PtrState.cpp Thu Sep 19 13:58:51 2019
@@ -275,6 +275,10 @@ void BottomUpPtrState::HandlePotentialUs
     } else {
       InsertAfter = std::next(Inst->getIterator());
     }
+
+    if (InsertAfter != BB->end())
+      InsertAfter = skipDebugIntrinsics(InsertAfter);
+
     InsertReverseInsertPt(&*InsertAfter);
   };
 

Added: llvm/trunk/test/Transforms/ObjCARC/code-motion.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ObjCARC/code-motion.ll?rev=372352&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/ObjCARC/code-motion.ll (added)
+++ llvm/trunk/test/Transforms/ObjCARC/code-motion.ll Thu Sep 19 13:58:51 2019
@@ -0,0 +1,39 @@
+; RUN: opt -objc-arc -S < %s | FileCheck %s
+
+declare void @alterRefCount()
+declare void @use(i8*)
+
+; Check that ARC optimizer doesn't reverse the order of the retain call and the
+; release call when there are debug instructions.
+
+; CHECK: call i8* @llvm.objc.retain(i8* %x)
+; CHECK: call void @llvm.objc.release(i8* %x)
+
+define i32 @test(i8* %x, i8* %y, i8 %z, i32 %i) {
+  %i.addr = alloca i32, align 4
+  store i32 %i, i32* %i.addr, align 4
+  %v1 = tail call i8* @llvm.objc.retain(i8* %x)
+  store i8 %z, i8* %x
+  call void @llvm.dbg.declare(metadata i32* %i.addr, metadata !9, metadata !DIExpression()), !dbg !10
+  call void @alterRefCount()
+  tail call void @llvm.objc.release(i8* %x)
+  ret i32 %i
+}
+
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
+declare i8* @llvm.objc.retain(i8*) local_unnamed_addr
+declare void @llvm.objc.release(i8*) local_unnamed_addr
+
+!llvm.module.flags = !{!0, !1}
+
+!0 = !{i32 2, !"Dwarf Version", i32 4}
+!1 = !{i32 2, !"Debug Info Version", i32 3}
+!2 = !DILocalVariable(name: "i", arg: 1, scope: !3, file: !4, line: 1, type: !7)
+!3 = distinct !DISubprogram(name: "test", scope: !4, file: !4, line: 1, type: !5, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !8, retainedNodes: !9)
+!4 = !DIFile(filename: "test.m", directory: "dir")
+!5 = !DISubroutineType(types: !6)
+!6 = !{!7, !7}
+!7 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!8 = distinct !DICompileUnit(language: DW_LANG_ObjC, file: !4, isOptimized: false, runtimeVersion: 2, emissionKind: FullDebug, enums: !9, nameTableKind: None)
+!9 = !{}
+!10 = !DILocation(line: 1, column: 14, scope: !3)