misc-ps-eager-assume.m revision fc8f0e14ad142ed811e90fbd9a30e419e301c717 
1// RUN: %clang_cc1 -analyze -analyzer-checker=core,core.experimental -analyzer-store=region -analyzer-constraints=range -verify -fblocks %s -analyzer-eagerly-assume
2
3// Delta-reduced header stuff (needed for test cases).
4typedef signed char BOOL;
5typedef unsigned int NSUInteger;
6typedef struct _NSZone NSZone;
7@class NSInvocation, NSMethodSignature, NSCoder, NSString, NSEnumerator;
8@protocol NSObject  - (BOOL)isEqual:(id)object;
9- (oneway void)release;
10@end  @protocol NSCopying  - (id)copyWithZone:(NSZone *)zone;
11@end  @protocol NSMutableCopying  - (id)mutableCopyWithZone:(NSZone *)zone;
12@end  @protocol NSCoding  - (void)encodeWithCoder:(NSCoder *)aCoder;
13@end    @interface NSObject <NSObject> {}
14+ (id)alloc;
15@end  typedef struct {}
16NSFastEnumerationState;
17@protocol NSFastEnumeration  - (NSUInteger)countByEnumeratingWithState:(NSFastEnumerationState *)state objects:(id *)stackbuf count:(NSUInteger)len;
18@end      @interface NSArray : NSObject <NSCopying, NSMutableCopying, NSCoding, NSFastEnumeration>  - (NSUInteger)count;
19@end    @interface NSMutableArray : NSArray  - (void)addObject:(id)anObject;
20- (BOOL)isEqualToString:(NSString *)aString;
21@end        @interface NSAutoreleasePool : NSObject {}
22- (void)drain;
23- (id)init;
24@end
25
26// This test case tests that (x != 0) is eagerly evaluated before stored to
27// 'y'.  This test case complements recoverCastedSymbol (see below) because
28// the symbolic expression is stored to 'y' (which is a short instead of an
29// int).  recoverCastedSymbol() only recovers path-sensitivity when the
30// symbolic expression is literally the branch condition.
31//
32void handle_assign_of_condition(int x) {
33  // The cast to 'short' causes us to lose symbolic constraint.
34  short y = (x != 0);
35  char *p = 0;
36  if (y) {
37    // This should be infeasible.
38    if (!(x != 0)) {
39      *p = 1;  // no-warning
40    }
41  }
42}
43
44// From <rdar://problem/6619921>
45//
46// In this test case, 'needsAnArray' is a signed char.  The analyzer tracks
47// a symbolic value for this variable, but in the branch condition it is
48// promoted to 'int'.  Currently the analyzer doesn't reason well about
49// promotions of symbolic values, so this test case tests the logic in
50// 'recoverCastedSymbol()' (GRExprEngine.cpp) to test that we recover
51// path-sensitivity and use the symbol for 'needsAnArray' in the branch
52// condition.
53//
54void handle_symbolic_cast_in_condition(void) {
55  NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
56
57  BOOL needsAnArray = [@"aString" isEqualToString:@"anotherString"];
58  NSMutableArray* array = needsAnArray ? [[NSMutableArray alloc] init] : 0;
59  if(needsAnArray)
60    [array release];
61
62  [pool drain];
63}
64
65// From PR 3836 (http://llvm.org/bugs/show_bug.cgi?id=3836)
66//
67// In this test case, the double '!' works fine with our symbolic constraints,
68// but we don't support comparing SymConstraint != SymConstraint.  By eagerly
69// assuming the truth of !!a or !!b, we can compare these values directly.
70//
71void pr3836(int *a, int *b) {
72  if (!!a != !!b) /* one of them is NULL */
73    return;
74  if (!a && !b) /* both are NULL */
75    return;
76      
77  *a = 1; // no-warning
78  *b = 1; // no-warning
79}
80
81
82//===---------------------------------------------------------------------===//
83// <rdar://problem/7342806>
84// This false positive occurred because the symbolic constraint on a short was
85// not maintained via sign extension.  The analyzer doesn't properly handle
86// the sign extension, but now tracks the constraint.  This particular
87// case relies on -analyzer-eagerly-assume because of the expression
88// 'Flag1 != Count > 0'.
89//===---------------------------------------------------------------------===//
90
91void rdar7342806_aux(short x);
92
93void rdar7342806() {
94  extern short Count;
95  extern short Flag1;
96
97  short *Pointer = 0;
98  short  Flag2   = !!Pointer;   // Flag2 is false (0).
99  short  Ok      = 1;
100  short  Which;
101
102  if( Flag1 != Count > 0 )
103    // Static analyzer skips this so either
104    //   Flag1 is true and Count > 0
105    // or
106    //   Flag1 is false and Count <= 0
107    Ok = 0;
108
109  if( Flag1 != Flag2 )
110    // Analyzer skips this so Flag1 and Flag2 have the
111    // same value, both are false because Flag2 is false. And
112    // from that we know Count must be <= 0.
113    Ok = 0;
114
115  for( Which = 0;
116         Which < Count && Ok;
117           Which++ )
118    // This statement can only execute if Count > 0 which can only
119    // happen when Flag1 and Flag2 are both true and Flag2 will only
120    // be true when Pointer is not NULL.
121    rdar7342806_aux(*Pointer); // no-warning
122}
123
124//===---------------------------------------------------------------------===//
125// PR 5627 - http://llvm.org/bugs/show_bug.cgi?id=5627
126//  This test case depends on using -analyzer-eagerly-assume and
127//  -analyzer-store=region.  The '-analyzer-eagerly-assume' causes the path
128//  to bifurcate when evaluating the function call argument, and a state
129//  caching bug in GRExprEngine::CheckerVisit (and friends) caused the store
130//  to 'p' to not be evaluated along one path, but then an autotransition caused
131//  the path to keep on propagating with 'p' still set to an undefined value.
132//  We would then get a bogus report of returning uninitialized memory.
133//  Note: CheckerVisit mistakenly cleared an existing node, and the cleared
134//  node was resurrected by GRStmtNodeBuilder::~GRStmtNodeBuilder(), where
135//  'p' was not assigned.
136//===---------------------------------------------------------------------===//
137
138float *pr5627_f(int y);
139
140float *pr5627_g(int x) {
141  float *p;
142  p = pr5627_f(!x);
143  return p; // no-warning
144}
145
146