[analyzer] Fix leak false positives on stuff put in C++/ObjC initializer lists.

The analyzer now realizes that C++ std::initializer_list objects and
Objective-C boxed structure/array/dictionary expressions can potentially
maintain a reference to the objects that were put into them. This avoids
false memory leak posivites and a few other issues.

This is a conservative behavior; for now, we do not model what actually happens
to the objects after being passed into such initializer lists.

rdar://problem/32918288
Differential Revision: https://reviews.llvm.org/D35216


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@314975 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 35 insertions, 0 deletions

diff --git a/test/Analysis/objc-boxing.m b/test/Analysis/objc-boxing.m
index 963374b3ef..66f24ddf77 100644
--- a/test/Analysis/objc-boxing.m
+++ b/test/Analysis/objc-boxing.m
@@ -5,6 +5,16 @@ void clang_analyzer_eval(int);
 typedef signed char BOOL;
 typedef long NSInteger;
 typedef unsigned long NSUInteger;
+
+@protocol NSObject
+@end
+@interface NSObject <NSObject> {}
+@end
+@protocol NSCopying
+@end
+@protocol NSCoding
+@end
+
 @interface NSString @end
 @interface NSString (NSStringExtensionMethods)
 + (id)stringWithUTF8String:(const char *)nullTerminatedCString;
@@ -28,7 +38,15 @@ typedef unsigned long NSUInteger;
 + (NSNumber *)numberWithUnsignedInteger:(NSUInteger)value ;
 @end
 
+@interface NSValue : NSObject <NSCopying, NSCoding>
+- (void)getValue:(void *)value;
++ (NSValue *)valueWithBytes:(const void *)value
+                   objCType:(const char *)type;
+@end
 
+typedef typeof(sizeof(int)) size_t;
+extern void *malloc(size_t);
+extern void free(void *);
 extern char *strdup(const char *str);
 
 id constant_string() {
@@ -39,6 +57,23 @@ id dynamic_string() {
     return @(strdup("boxed dynamic string")); // expected-warning{{Potential memory leak}}
 }
 
+typedef struct __attribute__((objc_boxable)) {
+  const char *str;
+} BoxableStruct;
+
+id leak_within_boxed_struct() {
+  BoxableStruct bs;
+  bs.str = strdup("dynamic string"); // The duped string shall be owned by val.
+  NSValue *val = @(bs); // no-warning
+  return val;
+}
+
+id leak_of_boxed_struct() {
+  BoxableStruct *bs = malloc(sizeof(BoxableStruct)); // The pointer stored in bs isn't owned by val.
+  NSValue *val = @(*bs); // expected-warning{{Potential leak of memory pointed to by 'bs'}}
+  return val;
+}
+
 id const_char_pointer(int *x) {
   if (x)
     return @(3);