[llvm-commits] [llvm] r140814 - in /llvm/trunk: lib/Transforms/Scalar/ObjCARC.cpp test/Transforms/ObjCARC/retain-block-alloca.ll
Dan Gohman
gohman at apple.com
Thu Sep 29 15:25:23 PDT 2011
Author: djg
Date: Thu Sep 29 17:25:23 2011
New Revision: 140814
URL: http://llvm.org/viewvc/llvm-project?rev=140814&view=rev
Log:
Don't eliminate objc_retainBlock calls on stack objects if the
objc_retainBlock call is potentially responsible for copying
the block to the heap to extend its lifetime. rdar://10209613.
Added:
llvm/trunk/test/Transforms/ObjCARC/retain-block-alloca.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp?rev=140814&r1=140813&r2=140814&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp Thu Sep 29 17:25:23 2011
@@ -2338,6 +2338,11 @@
S.SetAtLeastOneRefCount();
S.DecrementNestCount();
+ // An objc_retainBlock call with just a use still needs to be kept,
+ // because it may be copying a block from the stack to the heap.
+ if (Class == IC_RetainBlock && S.GetSeq() == S_Use)
+ S.SetSeq(S_CanRelease);
+
switch (S.GetSeq()) {
case S_Stop:
case S_Release:
@@ -2406,14 +2411,14 @@
case S_Release:
case S_MovableRelease:
if (CanUse(Inst, Ptr, PA, Class)) {
- S.RRI.ReverseInsertPts.clear();
+ assert(S.RRI.ReverseInsertPts.empty());
S.RRI.ReverseInsertPts.insert(Inst);
S.SetSeq(S_Use);
} else if (Seq == S_Release &&
(Class == IC_User || Class == IC_CallOrUser)) {
// Non-movable releases depend on any possible objc pointer use.
S.SetSeq(S_Stop);
- S.RRI.ReverseInsertPts.clear();
+ assert(S.RRI.ReverseInsertPts.empty());
S.RRI.ReverseInsertPts.insert(Inst);
}
break;
@@ -2566,7 +2571,7 @@
switch (Seq) {
case S_Retain:
S.SetSeq(S_CanRelease);
- S.RRI.ReverseInsertPts.clear();
+ assert(S.RRI.ReverseInsertPts.empty());
S.RRI.ReverseInsertPts.insert(Inst);
// One call can't cause a transition from S_Retain to S_CanRelease
@@ -2590,8 +2595,18 @@
if (CanUse(Inst, Ptr, PA, Class))
S.SetSeq(S_Use);
break;
- case S_Use:
case S_Retain:
+ // An objc_retainBlock call may be responsible for copying the block
+ // data from the stack to the heap. Model this by moving it straight
+ // from S_Retain to S_Use.
+ if (S.RRI.IsRetainBlock &&
+ CanUse(Inst, Ptr, PA, Class)) {
+ assert(S.RRI.ReverseInsertPts.empty());
+ S.RRI.ReverseInsertPts.insert(Inst);
+ S.SetSeq(S_Use);
+ }
+ break;
+ case S_Use:
case S_None:
break;
case S_Stop:
@@ -2743,17 +2758,23 @@
SmallVector<Instruction *, 8> DeadInsts;
for (MapVector<Value *, RRInfo>::const_iterator I = Retains.begin(),
- E = Retains.end(); I != E; ) {
- Value *V = (I++)->first;
+ E = Retains.end(); I != E; ++I) {
+ Value *V = I->first;
if (!V) continue; // blotted
Instruction *Retain = cast<Instruction>(V);
Value *Arg = GetObjCArg(Retain);
- // If the object being released is in static or stack storage, we know it's
+ // If the object being released is in static storage, we know it's
// not being managed by ObjC reference counting, so we can delete pairs
// regardless of what possible decrements or uses lie between them.
- bool KnownSafe = isa<Constant>(Arg) || isa<AllocaInst>(Arg);
+ bool KnownSafe = isa<Constant>(Arg);
+
+ // Same for stack storage, unless this is an objc_retainBlock call,
+ // which is responsible for copying the block data from the stack to
+ // the heap.
+ if (!I->second.IsRetainBlock && isa<AllocaInst>(Arg))
+ KnownSafe = true;
// A constant pointer can't be pointing to an object on the heap. It may
// be reference-counted, but it won't be deleted.
Added: llvm/trunk/test/Transforms/ObjCARC/retain-block-alloca.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ObjCARC/retain-block-alloca.ll?rev=140814&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/ObjCARC/retain-block-alloca.ll (added)
+++ llvm/trunk/test/Transforms/ObjCARC/retain-block-alloca.ll Thu Sep 29 17:25:23 2011
@@ -0,0 +1,54 @@
+; RUN: opt -S -objc-arc < %s | FileCheck %s
+; rdar://10209613
+
+; CHECK: define void @test
+; CHECK: %3 = call i8* @objc_retainBlock(i8* %2) nounwind
+; CHECK: @objc_msgSend
+; CHECK-NEXT: @objc_release(i8* %3)
+
+%0 = type opaque
+%struct.__block_descriptor = type { i64, i64 }
+
+ at _NSConcreteStackBlock = external global i8*
+ at __block_descriptor_tmp = external hidden constant { i64, i64, i8*, i8*, i8*, i8* }
+@"\01L_OBJC_SELECTOR_REFERENCES_" = external hidden global i8*, section "__DATA, __objc_selrefs, literal_pointers, no_dead_strip"
+
+define void @test(%0* %array) uwtable {
+entry:
+ %block = alloca <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>, align 8
+ %0 = bitcast %0* %array to i8*
+ %1 = tail call i8* @objc_retain(i8* %0) nounwind
+ %block.isa = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block, i64 0, i32 0
+ store i8* bitcast (i8** @_NSConcreteStackBlock to i8*), i8** %block.isa, align 8
+ %block.flags = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block, i64 0, i32 1
+ store i32 1107296256, i32* %block.flags, align 8
+ %block.reserved = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block, i64 0, i32 2
+ store i32 0, i32* %block.reserved, align 4
+ %block.invoke = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block, i64 0, i32 3
+ store i8* bitcast (void (i8*)* @__test_block_invoke_0 to i8*), i8** %block.invoke, align 8
+ %block.descriptor = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block, i64 0, i32 4
+ store %struct.__block_descriptor* bitcast ({ i64, i64, i8*, i8*, i8*, i8* }* @__block_descriptor_tmp to %struct.__block_descriptor*), %struct.__block_descriptor** %block.descriptor, align 8
+ %block.captured = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block, i64 0, i32 5
+ store %0* %array, %0** %block.captured, align 8
+ %2 = bitcast <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block to i8*
+ %3 = call i8* @objc_retainBlock(i8* %2) nounwind
+ %tmp2 = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_", align 8
+ call void bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to void (i8*, i8*, i8*)*)(i8* %0, i8* %tmp2, i8* %3)
+ call void @objc_release(i8* %3) nounwind
+ %strongdestroy = load %0** %block.captured, align 8
+ %4 = bitcast %0* %strongdestroy to i8*
+ call void @objc_release(i8* %4) nounwind, !clang.imprecise_release !0
+ ret void
+}
+
+declare i8* @objc_retain(i8*)
+
+declare void @__test_block_invoke_0(i8* nocapture) uwtable
+
+declare i8* @objc_retainBlock(i8*)
+
+declare i8* @objc_msgSend(i8*, i8*, ...) nonlazybind
+
+declare void @objc_release(i8*)
+
+!0 = metadata !{}
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