[analyzer] Make analyzer less aggressive when dealing with [self init].

With inlining, retain count checker starts tracking 'self' through the
init methods. The analyser results were too noisy if the developer
did not follow 'self = [super init]' pattern (which is common
especially in older code bases) - we reported self init anti-pattern AND
possible use-after-free. This patch teaches the retain count
checker to assume that [super init] does not fail when it's not consumed
by another expression. This silences the retain count warning that warns
about possibility of use-after-free when init fails, while preserving
all the other checking on 'self'.

llvm-svn: 162508

1 files changed, 68 insertions, 0 deletions

diff --git a/clang/test/Analysis/inlining/retain-count-self-init.m b/clang/test/Analysis/inlining/retain-count-self-init.m
new file mode 100644
index 00000000000..ee8dbe391c4
--- /dev/null
+++ b/clang/test/Analysis/inlining/retain-count-self-init.m
@@ -0,0 +1,68 @@
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,osx.cocoa.RetainCount,osx.cocoa.SelfInit -analyzer-ipa=dynamic-bifurcate -verify %s
+
+typedef signed char BOOL;
+typedef struct objc_class *Class;
+typedef struct objc_object {
+    Class isa;
+} *id;
+@protocol NSObject  - (BOOL)isEqual:(id)object; @end
+@interface NSObject <NSObject> {}
++(id)alloc;
++(id)new;
+- (oneway void)release;
+-(id)init;
+-(id)autorelease;
+-(id)copy;
+- (Class)class;
+-(id)retain;
+@end
+
+// We do not want to overhelm user with error messages in case they forgot to 
+// assign to self and check that the result of [super init] is non-nil. So 
+// stop tracking the receiver of init with respect to Retain Release checker.  
+// radar://12115830
+@interface ParentOfCell : NSObject
+- (id)initWithInt: (int)inInt;
+@end
+@interface Cell : ParentOfCell{
+  int x;
+}
+- (id)init;
++ (void)test;
+@property int x;
+@end
+@implementation Cell
+@synthesize x;
+- (id) init {
+  [super init];
+  self.x = 3; // no-warning 
+  return self; // expected-warning {{Returning 'self' while it is not set to the result of '[(super or self)}} 
+}
+- (id) initWithInt: (int)inInt {
+  [super initWithInt: inInt];
+  self.x = inInt; // no-warning 
+  return self; // expected-warning {{Returning 'self' while it is not set to the result of '[(super or self)}} 
+}
+- (id) init2 {
+  [self init]; // The call [self init] is inlined. We will warn inside the inlined body.
+  self.x = 2; // no-warning 
+  return self; 
+}
+
+- (id) initWithIntGood: (int)inInt {
+    if (self = [super initWithInt: inInt]) {
+      self.x = inInt; 
+    }
+    return self; 
+}
++ (void) test {
+  Cell *sharedCell1 = [[Cell alloc] init];
+  [sharedCell1 release];
+  Cell *sharedCell2 = [[Cell alloc] initWithInt: 3];
+  [sharedCell2 release];
+  Cell *sharedCell3 = [[Cell alloc] initWithIntGood: 3];
+  [sharedCell3 release];
+}
+
+@end
+