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-rw-r--r--lib/Transforms/ObjCARC/ObjCARCOpts.cpp48
-rw-r--r--test/Transforms/ObjCARC/allocas.ll200
2 files changed, 240 insertions, 8 deletions
diff --git a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
index 91490d1b2d..e6e1ff95aa 100644
--- a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -455,8 +455,13 @@ namespace {
/// sequence.
SmallPtrSet<Instruction *, 2> ReverseInsertPts;
+ /// If this is true, we cannot perform code motion but can still remove
+ /// retain/release pairs.
+ bool CFGHazardAfflicted;
+
RRInfo() :
- KnownSafe(false), IsTailCallRelease(false), ReleaseMetadata(0) {}
+ KnownSafe(false), IsTailCallRelease(false), ReleaseMetadata(0),
+ CFGHazardAfflicted(false) {}
void clear();
@@ -472,6 +477,7 @@ void RRInfo::clear() {
ReleaseMetadata = 0;
Calls.clear();
ReverseInsertPts.clear();
+ CFGHazardAfflicted = false;
}
namespace {
@@ -559,6 +565,7 @@ PtrState::Merge(const PtrState &Other, bool TopDown) {
RRI.IsTailCallRelease = RRI.IsTailCallRelease &&
Other.RRI.IsTailCallRelease;
RRI.Calls.insert(Other.RRI.Calls.begin(), Other.RRI.Calls.end());
+ RRI.CFGHazardAfflicted |= Other.RRI.CFGHazardAfflicted;
// Merge the insert point sets. If there are any differences,
// that makes this a partial merge.
@@ -1690,6 +1697,7 @@ static void CheckForUseCFGHazard(const Sequence SuccSSeq,
PtrState &S,
bool &SomeSuccHasSame,
bool &AllSuccsHaveSame,
+ bool &NotAllSeqEqualButKnownSafe,
bool &ShouldContinue) {
switch (SuccSSeq) {
case S_CanRelease: {
@@ -1697,6 +1705,7 @@ static void CheckForUseCFGHazard(const Sequence SuccSSeq,
S.ClearSequenceProgress();
break;
}
+ S.RRI.CFGHazardAfflicted = true;
ShouldContinue = true;
break;
}
@@ -1708,6 +1717,8 @@ static void CheckForUseCFGHazard(const Sequence SuccSSeq,
case S_MovableRelease:
if (!S.RRI.KnownSafe && !SuccSRRIKnownSafe)
AllSuccsHaveSame = false;
+ else
+ NotAllSeqEqualButKnownSafe = true;
break;
case S_Retain:
llvm_unreachable("bottom-up pointer in retain state!");
@@ -1723,7 +1734,8 @@ static void CheckForCanReleaseCFGHazard(const Sequence SuccSSeq,
const bool SuccSRRIKnownSafe,
PtrState &S,
bool &SomeSuccHasSame,
- bool &AllSuccsHaveSame) {
+ bool &AllSuccsHaveSame,
+ bool &NotAllSeqEqualButKnownSafe) {
switch (SuccSSeq) {
case S_CanRelease:
SomeSuccHasSame = true;
@@ -1734,6 +1746,8 @@ static void CheckForCanReleaseCFGHazard(const Sequence SuccSSeq,
case S_Use:
if (!S.RRI.KnownSafe && !SuccSRRIKnownSafe)
AllSuccsHaveSame = false;
+ else
+ NotAllSeqEqualButKnownSafe = true;
break;
case S_Retain:
llvm_unreachable("bottom-up pointer in retain state!");
@@ -1769,6 +1783,7 @@ ObjCARCOpt::CheckForCFGHazards(const BasicBlock *BB,
const TerminatorInst *TI = cast<TerminatorInst>(&BB->back());
bool SomeSuccHasSame = false;
bool AllSuccsHaveSame = true;
+ bool NotAllSeqEqualButKnownSafe = false;
succ_const_iterator SI(TI), SE(TI, false);
@@ -1800,17 +1815,17 @@ ObjCARCOpt::CheckForCFGHazards(const BasicBlock *BB,
switch(S.GetSeq()) {
case S_Use: {
bool ShouldContinue = false;
- CheckForUseCFGHazard(SuccSSeq, SuccSRRIKnownSafe, S,
- SomeSuccHasSame, AllSuccsHaveSame,
+ CheckForUseCFGHazard(SuccSSeq, SuccSRRIKnownSafe, S, SomeSuccHasSame,
+ AllSuccsHaveSame, NotAllSeqEqualButKnownSafe,
ShouldContinue);
if (ShouldContinue)
continue;
break;
}
case S_CanRelease: {
- CheckForCanReleaseCFGHazard(SuccSSeq, SuccSRRIKnownSafe,
- S, SomeSuccHasSame,
- AllSuccsHaveSame);
+ CheckForCanReleaseCFGHazard(SuccSSeq, SuccSRRIKnownSafe, S,
+ SomeSuccHasSame, AllSuccsHaveSame,
+ NotAllSeqEqualButKnownSafe);
break;
}
case S_Retain:
@@ -1825,8 +1840,15 @@ ObjCARCOpt::CheckForCFGHazards(const BasicBlock *BB,
// If the state at the other end of any of the successor edges
// matches the current state, require all edges to match. This
// guards against loops in the middle of a sequence.
- if (SomeSuccHasSame && !AllSuccsHaveSame)
+ if (SomeSuccHasSame && !AllSuccsHaveSame) {
S.ClearSequenceProgress();
+ } else if (NotAllSeqEqualButKnownSafe) {
+ // If we would have cleared the state foregoing the fact that we are known
+ // safe, stop code motion. This is because whether or not it is safe to
+ // remove RR pairs via KnownSafe is an orthogonal concept to whether we
+ // are allowed to perform code motion.
+ S.RRI.CFGHazardAfflicted = true;
+ }
}
}
@@ -2489,6 +2511,7 @@ ObjCARCOpt::ConnectTDBUTraversals(DenseMap<const BasicBlock *, BBState>
// we are dealing with a retainable object with multiple provenance sources.
bool KnownSafeTD = true, KnownSafeBU = true;
bool MultipleOwners = false;
+ bool CFGHazardAfflicted = false;
// Connect the dots between the top-down-collected RetainsToMove and
// bottom-up-collected ReleasesToMove to form sets of related calls.
@@ -2565,6 +2588,7 @@ ObjCARCOpt::ConnectTDBUTraversals(DenseMap<const BasicBlock *, BBState>
assert(It != Releases.end());
const RRInfo &NewReleaseRRI = It->second;
KnownSafeBU &= NewReleaseRRI.KnownSafe;
+ CFGHazardAfflicted |= NewReleaseRRI.CFGHazardAfflicted;
for (SmallPtrSet<Instruction *, 2>::const_iterator
LI = NewReleaseRRI.Calls.begin(),
LE = NewReleaseRRI.Calls.end(); LI != LE; ++LI) {
@@ -2618,6 +2642,14 @@ ObjCARCOpt::ConnectTDBUTraversals(DenseMap<const BasicBlock *, BBState>
// less aggressive solution which is.
if (NewDelta != 0)
return false;
+
+ // At this point, we are not going to remove any RR pairs, but we still are
+ // able to move RR pairs. If one of our pointers is afflicted with
+ // CFGHazards, we cannot perform such code motion so exit early.
+ const bool WillPerformCodeMotion = RetainsToMove.ReverseInsertPts.size() ||
+ ReleasesToMove.ReverseInsertPts.size();
+ if (CFGHazardAfflicted && WillPerformCodeMotion)
+ return false;
}
// Determine whether the original call points are balanced in the retain and
diff --git a/test/Transforms/ObjCARC/allocas.ll b/test/Transforms/ObjCARC/allocas.ll
index 58740d2d80..50656739ae 100644
--- a/test/Transforms/ObjCARC/allocas.ll
+++ b/test/Transforms/ObjCARC/allocas.ll
@@ -18,6 +18,8 @@ declare void @callee()
declare void @callee_fnptr(void ()*)
declare void @invokee()
declare i8* @returner()
+declare i8* @returner1()
+declare i8* @returner2()
declare void @bar(i32 ()*)
declare void @use_alloca(i8**)
@@ -295,6 +297,204 @@ bb3:
ret void
}
+; CHECK: define void @test2d(i8* %x)
+; CHECK: @objc_retain(i8* %x)
+; CHECK: @objc_retain(i8* %x)
+; CHECK: @objc_release(i8* %y)
+; CHECK: @objc_release(i8* %x)
+; CHECK: ret void
+; CHECK: }
+define void @test2d(i8* %x) {
+entry:
+ tail call i8* @objc_retain(i8* %x)
+ br label %bb1
+
+bb1:
+ %Abb1 = alloca i8*, i32 3
+ %gepbb11 = getelementptr i8** %Abb1, i32 2
+ store i8* %x, i8** %gepbb11, align 8
+ %gepbb12 = getelementptr i8** %Abb1, i32 2
+ %ybb1 = load i8** %gepbb12
+ br label %bb3
+
+bb2:
+ %Abb2 = alloca i8*, i32 4
+ %gepbb21 = getelementptr i8** %Abb2, i32 2
+ store i8* %x, i8** %gepbb21, align 8
+ %gepbb22 = getelementptr i8** %Abb2, i32 2
+ %ybb2 = load i8** %gepbb22
+ br label %bb3
+
+bb3:
+ %A = phi i8** [ %Abb1, %bb1 ], [ %Abb2, %bb2 ]
+ %y = phi i8* [ %ybb1, %bb1 ], [ %ybb2, %bb2 ]
+ tail call i8* @objc_retain(i8* %x)
+ call void @use_alloca(i8** %A)
+ call void @objc_release(i8* %y), !clang.imprecise_release !0
+ call void @use_pointer(i8* %x)
+ call void @objc_release(i8* %x), !clang.imprecise_release !0
+ ret void
+}
+
+; Make sure in the presense of allocas, if we find a cfghazard we do not perform
+; code motion even if we are known safe. These two concepts are separate and
+; should be treated as such.
+;
+; rdar://13949644
+
+; CHECK: define void @test3a() {
+; CHECK: entry:
+; CHECK: @objc_retainAutoreleasedReturnValue
+; CHECK: @objc_retain
+; CHECK: @objc_retain
+; CHECK: @objc_retain
+; CHECK: @objc_retain
+; CHECK: arraydestroy.body:
+; CHECK: @objc_release
+; CHECK-NOT: @objc_release
+; CHECK: arraydestroy.done:
+; CHECK-NOT: @objc_release
+; CHECK: arraydestroy.body1:
+; CHECK: @objc_release
+; CHECK-NOT: @objc_release
+; CHECK: arraydestroy.done1:
+; CHECK: @objc_release
+; CHECK: ret void
+; CHECK: }
+define void @test3a() {
+entry:
+ %keys = alloca [2 x i8*], align 16
+ %objs = alloca [2 x i8*], align 16
+
+ %call1 = call i8* @returner()
+ %tmp0 = tail call i8* @objc_retainAutoreleasedReturnValue(i8* %call1)
+
+ %objs.begin = getelementptr inbounds [2 x i8*]* %objs, i64 0, i64 0
+ tail call i8* @objc_retain(i8* %call1)
+ store i8* %call1, i8** %objs.begin, align 8
+ %objs.elt = getelementptr inbounds [2 x i8*]* %objs, i64 0, i64 1
+ tail call i8* @objc_retain(i8* %call1)
+ store i8* %call1, i8** %objs.elt
+
+ %call2 = call i8* @returner1()
+ %call3 = call i8* @returner2()
+ %keys.begin = getelementptr inbounds [2 x i8*]* %keys, i64 0, i64 0
+ tail call i8* @objc_retain(i8* %call2)
+ store i8* %call2, i8** %keys.begin, align 8
+ %keys.elt = getelementptr inbounds [2 x i8*]* %keys, i64 0, i64 1
+ tail call i8* @objc_retain(i8* %call3)
+ store i8* %call3, i8** %keys.elt
+
+ %gep = getelementptr inbounds [2 x i8*]* %objs, i64 0, i64 2
+ br label %arraydestroy.body
+
+arraydestroy.body:
+ %arraydestroy.elementPast = phi i8** [ %gep, %entry ], [ %arraydestroy.element, %arraydestroy.body ]
+ %arraydestroy.element = getelementptr inbounds i8** %arraydestroy.elementPast, i64 -1
+ %destroy_tmp = load i8** %arraydestroy.element, align 8
+ call void @objc_release(i8* %destroy_tmp), !clang.imprecise_release !0
+ %objs_ptr = getelementptr inbounds [2 x i8*]* %objs, i64 0, i64 0
+ %arraydestroy.cmp = icmp eq i8** %arraydestroy.element, %objs_ptr
+ br i1 %arraydestroy.cmp, label %arraydestroy.done, label %arraydestroy.body
+
+arraydestroy.done:
+ %gep1 = getelementptr inbounds [2 x i8*]* %keys, i64 0, i64 2
+ br label %arraydestroy.body1
+
+arraydestroy.body1:
+ %arraydestroy.elementPast1 = phi i8** [ %gep1, %arraydestroy.done ], [ %arraydestroy.element1, %arraydestroy.body1 ]
+ %arraydestroy.element1 = getelementptr inbounds i8** %arraydestroy.elementPast1, i64 -1
+ %destroy_tmp1 = load i8** %arraydestroy.element1, align 8
+ call void @objc_release(i8* %destroy_tmp1), !clang.imprecise_release !0
+ %keys_ptr = getelementptr inbounds [2 x i8*]* %keys, i64 0, i64 0
+ %arraydestroy.cmp1 = icmp eq i8** %arraydestroy.element1, %keys_ptr
+ br i1 %arraydestroy.cmp1, label %arraydestroy.done1, label %arraydestroy.body1
+
+arraydestroy.done1:
+ call void @objc_release(i8* %call1), !clang.imprecise_release !0
+ ret void
+}
+
+; Make sure that even though we stop said code motion we still allow for
+; pointers to be removed if we are known safe in both directions.
+;
+; rdar://13949644
+
+; CHECK: define void @test3b() {
+; CHECK: entry:
+; CHECK: @objc_retainAutoreleasedReturnValue
+; CHECK: @objc_retain
+; CHECK: @objc_retain
+; CHECK: @objc_retain
+; CHECK: @objc_retain
+; CHECK: arraydestroy.body:
+; CHECK: @objc_release
+; CHECK-NOT: @objc_release
+; CHECK: arraydestroy.done:
+; CHECK-NOT: @objc_release
+; CHECK: arraydestroy.body1:
+; CHECK: @objc_release
+; CHECK-NOT: @objc_release
+; CHECK: arraydestroy.done1:
+; CHECK: @objc_release
+; CHECK: ret void
+; CHECK: }
+define void @test3b() {
+entry:
+ %keys = alloca [2 x i8*], align 16
+ %objs = alloca [2 x i8*], align 16
+
+ %call1 = call i8* @returner()
+ %tmp0 = tail call i8* @objc_retainAutoreleasedReturnValue(i8* %call1)
+ %tmp1 = tail call i8* @objc_retain(i8* %call1)
+
+ %objs.begin = getelementptr inbounds [2 x i8*]* %objs, i64 0, i64 0
+ tail call i8* @objc_retain(i8* %call1)
+ store i8* %call1, i8** %objs.begin, align 8
+ %objs.elt = getelementptr inbounds [2 x i8*]* %objs, i64 0, i64 1
+ tail call i8* @objc_retain(i8* %call1)
+ store i8* %call1, i8** %objs.elt
+
+ %call2 = call i8* @returner1()
+ %call3 = call i8* @returner2()
+ %keys.begin = getelementptr inbounds [2 x i8*]* %keys, i64 0, i64 0
+ tail call i8* @objc_retain(i8* %call2)
+ store i8* %call2, i8** %keys.begin, align 8
+ %keys.elt = getelementptr inbounds [2 x i8*]* %keys, i64 0, i64 1
+ tail call i8* @objc_retain(i8* %call3)
+ store i8* %call3, i8** %keys.elt
+
+ %gep = getelementptr inbounds [2 x i8*]* %objs, i64 0, i64 2
+ br label %arraydestroy.body
+
+arraydestroy.body:
+ %arraydestroy.elementPast = phi i8** [ %gep, %entry ], [ %arraydestroy.element, %arraydestroy.body ]
+ %arraydestroy.element = getelementptr inbounds i8** %arraydestroy.elementPast, i64 -1
+ %destroy_tmp = load i8** %arraydestroy.element, align 8
+ call void @objc_release(i8* %destroy_tmp), !clang.imprecise_release !0
+ %objs_ptr = getelementptr inbounds [2 x i8*]* %objs, i64 0, i64 0
+ %arraydestroy.cmp = icmp eq i8** %arraydestroy.element, %objs_ptr
+ br i1 %arraydestroy.cmp, label %arraydestroy.done, label %arraydestroy.body
+
+arraydestroy.done:
+ %gep1 = getelementptr inbounds [2 x i8*]* %keys, i64 0, i64 2
+ br label %arraydestroy.body1
+
+arraydestroy.body1:
+ %arraydestroy.elementPast1 = phi i8** [ %gep1, %arraydestroy.done ], [ %arraydestroy.element1, %arraydestroy.body1 ]
+ %arraydestroy.element1 = getelementptr inbounds i8** %arraydestroy.elementPast1, i64 -1
+ %destroy_tmp1 = load i8** %arraydestroy.element1, align 8
+ call void @objc_release(i8* %destroy_tmp1), !clang.imprecise_release !0
+ %keys_ptr = getelementptr inbounds [2 x i8*]* %keys, i64 0, i64 0
+ %arraydestroy.cmp1 = icmp eq i8** %arraydestroy.element1, %keys_ptr
+ br i1 %arraydestroy.cmp1, label %arraydestroy.done1, label %arraydestroy.body1
+
+arraydestroy.done1:
+ call void @objc_release(i8* %call1), !clang.imprecise_release !0
+ call void @objc_release(i8* %call1), !clang.imprecise_release !0
+ ret void
+}
+
!0 = metadata !{}
declare i32 @__gxx_personality_v0(...)
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-24 12:46:15 +0000