Fix horrible non-termination bug in LiveVariables. The issue was that

the liveness state of block-level expressions could oscillate because
of two issues:
- The initial value before a merge was not always set to "Top"
- The set of live block-level expressions is a union, not an intersection

This fixes <rdar://problem/650084>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63421 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 36 insertions, 0 deletions

diff --git a/test/Analysis/rdar-6540084.m b/test/Analysis/rdar-6540084.m
new file mode 100644
index 0000000000..e1347d92eb
--- /dev/null
+++ b/test/Analysis/rdar-6540084.m
@@ -0,0 +1,36 @@
+// RUN: clang -analyze -warn-dead-stores -verify %s
+//
+// This test exercises the live variables analysis (LiveVariables.cpp).
+// The case originally identified a non-termination bug.
+//
+typedef signed char BOOL;
+typedef unsigned int NSUInteger;
+typedef struct _NSZone NSZone;
+@protocol NSObject  - (BOOL)isEqual:(id)object; @end
+@interface NSObject <NSObject> {} @end
+extern id NSAllocateObject(Class aClass, NSUInteger extraBytes, NSZone *zone);
+@class NSArray;
+@class NSMutableArray, NSIndexSet, NSView, NSPredicate, NSString, NSViewAnimation, NSTimer;
+@interface FooBazController : NSObject {}
+@end
+typedef struct {} TazVersion;
+@class TazNode;
+@interface TazGuttenberg : NSObject {} typedef NSUInteger BugsBunnyType; @end
+@interface FooBaz : NSObject {}
+@property (nonatomic) BugsBunnyType matchType;
+@property (nonatomic, retain) NSArray *papyrus; @end
+@implementation FooBazController
+- (NSArray *)excitingStuff:(FooBaz *)options {
+  BugsBunnyType matchType = options.matchType;
+  NSPredicate *isSearchablePredicate = [NSPredicate predicateWithFormat:@"isSearchable == YES"]; // expected-warning{{return type defaults to 'id'}}
+  for (TazGuttenberg *Guttenberg in options.papyrus) {
+    NSArray *GuttenbergNodes = [Guttenberg nodes]; // expected-warning{{return type defaults to 'id'}}
+    NSArray *searchableNodes = [GuttenbergNodes filteredArrayUsingPredicate:isSearchablePredicate]; // expected-warning{{return type defaults to 'id'}}
+    for (TazNode *node in searchableNodes) {
+      switch (matchType) {
+        default: break;
+      }
+    }
+  }
+}
+@end