[objc-arc] Convert the one directional retain/release relation assert 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

2 files changed, 294 insertions, 3 deletions

diff --git a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
index b419a7ecc8..1cc665b2e0 100644
--- a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -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
@@ -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()];
diff --git a/test/Transforms/ObjCARC/path-overflow.ll b/test/Transforms/ObjCARC/path-overflow.ll
index e62a70da20..3c14353947 100644
--- a/test/Transforms/ObjCARC/path-overflow.ll
+++ b/test/Transforms/ObjCARC/path-overflow.ll
@@ -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
@@ -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
@@ -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() {
@@ -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 !{}