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[objc-arc] Convert the one directional retain/release relation assert…
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… to a conditional check + fail.

Due to the previously added overflow checks, we can have a retain/release
relation that is one directional. This occurs specifically when we run into an
additive overflow causing us to drop state in only one direction. If that
occurs, we should bail and not optimize that retain/release instead of
asserting.

Apologies for the size of the testcase. It is necessary to cause the additive
cfg overflow to trigger.

rdar://15377890

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194083 91177308-0d34-0410-b5e6-96231b3b80d8
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@gottesmm
gottesmm committed Nov 5, 2013
1 parent 04ae34b commit f23af8b
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Showing 2 changed files with 294 additions and 3 deletions.
21 changes: 18 additions & 3 deletions lib/Transforms/ObjCARC/ObjCARCOpts.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2405,7 +2405,15 @@ ObjCARCOpt::ConnectTDBUTraversals(DenseMap<const BasicBlock *, BBState>
if (Jt == Releases.end())
return false;
const RRInfo &NewRetainReleaseRRI = Jt->second;
assert(NewRetainReleaseRRI.Calls.count(NewRetain));

// If the release does not have a reference to the retain as well,
// something happened which is unaccounted for. Do not do anything.
//
// This can happen if we catch an additive overflow during path count
// merging.
if (!NewRetainReleaseRRI.Calls.count(NewRetain))
return false;

if (ReleasesToMove.Calls.insert(NewRetainRelease)) {

// If we overflow when we compute the path count, don't remove/move
Expand Down Expand Up @@ -2481,9 +2489,16 @@ ObjCARCOpt::ConnectTDBUTraversals(DenseMap<const BasicBlock *, BBState>
if (Jt == Retains.end())
return false;
const RRInfo &NewReleaseRetainRRI = Jt->second;
assert(NewReleaseRetainRRI.Calls.count(NewRelease));
if (RetainsToMove.Calls.insert(NewReleaseRetain)) {

// If the retain does not have a reference to the release as well,
// something happened which is unaccounted for. Do not do anything.
//
// This can happen if we catch an additive overflow during path count
// merging.
if (!NewReleaseRetainRRI.Calls.count(NewRelease))
return false;

if (RetainsToMove.Calls.insert(NewReleaseRetain)) {
// If we overflow when we compute the path count, don't remove/move
// anything.
const BBState &NRRBBState = BBStates[NewReleaseRetain->getParent()];
Expand Down
276 changes: 276 additions & 0 deletions test/Transforms/ObjCARC/path-overflow.ll
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
; rdar://12277446
; rdar://12480535
; rdar://14590914
; rdar://15377890

; The total number of paths grows exponentially with the number of branches, and a
; computation of this number can overflow any reasonable fixed-sized
Expand All @@ -15,6 +16,7 @@ target triple = "thumbv7-apple-ios5.0.0"
%struct.CGPoint = type { float, float }

@_unnamed_cfstring = external constant %struct.NSConstantString, section "__DATA,__cfstring"
@_unnamed_cfstring_2 = external constant %struct.NSConstantString, section "__DATA,__cfstring"

declare i8* @objc_retain(i8*) nonlazybind
declare i8* @objc_retainAutoreleasedReturnValue(i8*) nonlazybind
Expand All @@ -24,6 +26,7 @@ declare i8* @objc_msgSend(i8*, i8*, ...) nonlazybind
declare void @NSLog(i8*, ...)
declare void @objc_msgSend_stret(i8*, i8*, ...)
declare i32 @__gxx_personality_sj0(...)
declare i32 @__objc_personality_v0(...)


define hidden void @test1() {
Expand Down Expand Up @@ -1914,4 +1917,277 @@ eh.resume: ; preds = %lpad580, %ehcleanup
resume { i8*, i32 } undef
}

@"OBJC_EHTYPE_$_NSException" = external global i8

define void @test4() {
entry:
br i1 undef, label %if.end13, label %if.then10

if.then10: ; preds = %entry
br label %if.end13

if.end13: ; preds = %if.then10, %entry
%0 = call i8* bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to i8* (i8*, i8*, i8*, i64, i8*, i8)*)(i8* undef, i8* undef, i8* bitcast (%struct.NSConstantString* @_unnamed_cfstring to i8*), i64 2, i8* bitcast (%struct.NSConstantString* @_unnamed_cfstring_2 to i8*), i8 signext 0), !clang.arc.no_objc_arc_exceptions !0
br i1 undef, label %if.then17, label %if.end18

if.then17: ; preds = %if.end13
br label %if.end18

if.end18: ; preds = %if.then17, %if.end13
br i1 undef, label %if.then64, label %if.end73

if.then64: ; preds = %if.end18
br i1 undef, label %cond.end71, label %cond.true68

cond.true68: ; preds = %if.then64
br label %cond.end71

cond.end71: ; preds = %cond.true68, %if.then64
br i1 undef, label %cleanup.action, label %cleanup.done

cleanup.action: ; preds = %cond.end71
br label %cleanup.done

cleanup.done: ; preds = %cleanup.action, %cond.end71
br label %if.end73

if.end73: ; preds = %cleanup.done, %if.end18
br i1 undef, label %forcoll.empty, label %forcoll.loopinit

forcoll.loopinit: ; preds = %if.end73
br label %forcoll.loopbody.outer

forcoll.loopbody.outer: ; preds = %forcoll.refetch, %forcoll.loopinit
br label %forcoll.loopbody

forcoll.loopbody: ; preds = %forcoll.notmutated, %forcoll.loopbody.outer
br i1 undef, label %forcoll.notmutated, label %forcoll.mutated

forcoll.mutated: ; preds = %forcoll.loopbody
br label %forcoll.notmutated

forcoll.notmutated: ; preds = %forcoll.mutated, %forcoll.loopbody
br i1 undef, label %forcoll.loopbody, label %forcoll.refetch

forcoll.refetch: ; preds = %forcoll.notmutated
br i1 undef, label %forcoll.empty, label %forcoll.loopbody.outer

forcoll.empty: ; preds = %forcoll.refetch, %if.end73
br i1 undef, label %if.end85, label %if.then82

if.then82: ; preds = %forcoll.empty
br label %if.end85

if.end85: ; preds = %if.then82, %forcoll.empty
br i1 undef, label %if.then87, label %if.end102

if.then87: ; preds = %if.end85
br i1 undef, label %if.end94, label %if.then91

if.then91: ; preds = %if.then87
br label %if.end94

if.end94: ; preds = %if.then91, %if.then87
br i1 undef, label %if.end101, label %if.then98

if.then98: ; preds = %if.end94
br label %if.end101

if.end101: ; preds = %if.then98, %if.end94
br label %if.end102

if.end102: ; preds = %if.end101, %if.end85
br i1 undef, label %do.body113, label %if.then107

if.then107: ; preds = %if.end102
br label %do.body113

do.body113: ; preds = %if.then107, %if.end102
br i1 undef, label %if.then116, label %if.end117

if.then116: ; preds = %do.body113
br label %if.end117

if.end117: ; preds = %if.then116, %do.body113
br i1 undef, label %if.then125, label %if.end126

if.then125: ; preds = %if.end117
br label %if.end126

if.end126: ; preds = %if.then125, %if.end117
br i1 undef, label %do.end166, label %cond.true132

cond.true132: ; preds = %if.end126
br i1 undef, label %do.body148, label %cond.true151

do.body148: ; preds = %cond.true132
br i1 undef, label %do.end166, label %cond.true151

cond.true151: ; preds = %do.body148, %cond.true132
br i1 undef, label %if.then162, label %do.end166

if.then162: ; preds = %cond.true151
br label %do.end166

do.end166: ; preds = %if.then162, %cond.true151, %do.body148, %if.end126
br i1 undef, label %if.then304, label %if.then170

if.then170: ; preds = %do.end166
br i1 undef, label %do.end193, label %cond.true179

cond.true179: ; preds = %if.then170
br i1 undef, label %if.then190, label %do.end193

if.then190: ; preds = %cond.true179
br label %do.end193

do.end193: ; preds = %if.then190, %cond.true179, %if.then170
br i1 undef, label %do.body200, label %do.body283

do.body200: ; preds = %do.end193
br i1 undef, label %do.end254, label %cond.true203

cond.true203: ; preds = %do.body200
br i1 undef, label %do.body218, label %cond.true221

do.body218: ; preds = %cond.true203
br i1 undef, label %do.end254, label %cond.true221

cond.true221: ; preds = %do.body218, %cond.true203
br i1 undef, label %if.then232, label %do.body236

if.then232: ; preds = %cond.true221
br label %do.body236

do.body236: ; preds = %if.then232, %cond.true221
br i1 undef, label %do.end254, label %cond.true239

cond.true239: ; preds = %do.body236
br i1 undef, label %if.then250, label %do.end254

if.then250: ; preds = %cond.true239
br label %do.end254

do.end254: ; preds = %if.then250, %cond.true239, %do.body236, %do.body218, %do.body200
br i1 undef, label %do.end277, label %cond.true263

cond.true263: ; preds = %do.end254
br i1 undef, label %if.then274, label %do.end277

if.then274: ; preds = %cond.true263
unreachable

do.end277: ; preds = %cond.true263, %do.end254
br i1 undef, label %if.then280, label %do.body283

if.then280: ; preds = %do.end277
br label %do.body283

do.body283: ; preds = %if.then280, %do.end277, %do.end193
br i1 undef, label %if.end301, label %cond.true286

cond.true286: ; preds = %do.body283
br i1 undef, label %if.then297, label %if.end301

if.then297: ; preds = %cond.true286
br label %if.end301

if.end301: ; preds = %if.then297, %cond.true286, %do.body283
br i1 undef, label %if.then304, label %do.body351

if.then304: ; preds = %if.end301, %do.end166
br i1 undef, label %do.body309.lr.ph, label %do.body351

do.body309.lr.ph: ; preds = %if.then304
br label %do.body309

do.body309: ; preds = %for.cond.backedge, %do.body309.lr.ph
br i1 undef, label %do.end328, label %cond.true312

cond.true312: ; preds = %do.body309
br i1 undef, label %if.then323, label %do.end328

if.then323: ; preds = %cond.true312
br label %do.end328

do.end328: ; preds = %if.then323, %cond.true312, %do.body309
br i1 undef, label %for.cond.backedge, label %cond.true335

for.cond.backedge: ; preds = %if.then346, %cond.true335, %do.end328
br i1 undef, label %do.body309, label %do.body351

cond.true335: ; preds = %do.end328
br i1 undef, label %if.then346, label %for.cond.backedge

if.then346: ; preds = %cond.true335
br label %for.cond.backedge

do.body351: ; preds = %for.cond.backedge, %if.then304, %if.end301
br i1 undef, label %if.then354, label %if.end355

if.then354: ; preds = %do.body351
br label %if.end355

if.end355: ; preds = %if.then354, %do.body351
br i1 undef, label %if.else, label %if.then364

if.then364: ; preds = %if.end355
br label %do.body366

if.else: ; preds = %if.end355
br label %do.body366

do.body366: ; preds = %if.else, %if.then364
br i1 undef, label %if.then369, label %if.end377.critedge

if.then369: ; preds = %do.body366
br label %if.end377

if.end377.critedge: ; preds = %do.body366
br label %if.end377

if.end377: ; preds = %if.end377.critedge, %if.then369
br i1 undef, label %if.then383, label %if.end392.critedge

if.then383: ; preds = %if.end377
br label %if.end392

if.end392.critedge: ; preds = %if.end377
br label %if.end392

if.end392: ; preds = %if.end392.critedge, %if.then383
br i1 undef, label %if.then398, label %if.end399

if.then398: ; preds = %if.end392
br label %if.end399

if.end399: ; preds = %if.then398, %if.end392
invoke void bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to void (i8*, i8*)*)(i8* undef, i8* undef)
to label %eh.cont unwind label %lpad, !clang.arc.no_objc_arc_exceptions !0

eh.cont: ; preds = %if.end399
br i1 undef, label %if.then430, label %if.end439.critedge

if.then430: ; preds = %eh.cont
%1 = call i8* @objc_retain(i8* %0)
br label %if.end439

lpad: ; preds = %if.end399
%2 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__objc_personality_v0 to i8*)
catch i8* @"OBJC_EHTYPE_$_NSException"
unreachable

if.end439.critedge: ; preds = %eh.cont
%3 = call i8* @objc_retain(i8* %0)
br label %if.end439

if.end439: ; preds = %if.end439.critedge, %if.then430
call void @objc_release(i8* %0), !clang.imprecise_release !0
unreachable

return: ; No predecessors!
ret void
}


!0 = metadata !{}

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