malloc.c revision 033a07e5fca459ed184369cfee7c90d82367a93a
1// RUN: %clang_cc1 -analyze -analyzer-checker=core,experimental.deadcode.UnreachableCode,experimental.core.CastSize,experimental.unix.Malloc -analyzer-store=region -verify %s 2typedef __typeof(sizeof(int)) size_t; 3void *malloc(size_t); 4void free(void *); 5void *realloc(void *ptr, size_t size); 6void *calloc(size_t nmemb, size_t size); 7void __attribute((ownership_returns(malloc))) *my_malloc(size_t); 8void __attribute((ownership_takes(malloc, 1))) my_free(void *); 9void __attribute((ownership_returns(malloc, 1))) *my_malloc2(size_t); 10void __attribute((ownership_holds(malloc, 1))) my_hold(void *); 11 12// Duplicate attributes are silly, but not an error. 13// Duplicate attribute has no extra effect. 14// If two are of different kinds, that is an error and reported as such. 15void __attribute((ownership_holds(malloc, 1))) 16__attribute((ownership_holds(malloc, 1))) 17__attribute((ownership_holds(malloc, 3))) my_hold2(void *, void *, void *); 18void *my_malloc3(size_t); 19void *myglobalpointer; 20struct stuff { 21 void *somefield; 22}; 23struct stuff myglobalstuff; 24 25void f1() { 26 int *p = malloc(12); 27 return; // expected-warning{{Allocated memory never released. Potential memory leak.}} 28} 29 30void f2() { 31 int *p = malloc(12); 32 free(p); 33 free(p); // expected-warning{{Try to free a memory block that has been released}} 34} 35 36void f2_realloc_0() { 37 int *p = malloc(12); 38 realloc(p,0); 39 realloc(p,0); // expected-warning{{Try to free a memory block that has been released}} 40} 41 42void f2_realloc_1() { 43 int *p = malloc(12); 44 int *q = realloc(p,0); // expected-warning{{Assigned value is garbage or undefined}} 45} 46 47// ownership attributes tests 48void naf1() { 49 int *p = my_malloc3(12); 50 return; // no-warning 51} 52 53void n2af1() { 54 int *p = my_malloc2(12); 55 return; // expected-warning{{Allocated memory never released. Potential memory leak.}} 56} 57 58void af1() { 59 int *p = my_malloc(12); 60 return; // expected-warning{{Allocated memory never released. Potential memory leak.}} 61} 62 63void af1_b() { 64 int *p = my_malloc(12); // expected-warning{{Allocated memory never released. Potential memory leak.}} 65} 66 67void af1_c() { 68 myglobalpointer = my_malloc(12); // no-warning 69} 70 71void af1_d() { 72 struct stuff mystuff; 73 mystuff.somefield = my_malloc(12); // expected-warning{{Allocated memory never released. Potential memory leak.}} 74} 75 76// Test that we can pass out allocated memory via pointer-to-pointer. 77void af1_e(void **pp) { 78 *pp = my_malloc(42); // no-warning 79} 80 81void af1_f(struct stuff *somestuff) { 82 somestuff->somefield = my_malloc(12); // no-warning 83} 84 85// Allocating memory for a field via multiple indirections to our arguments is OK. 86void af1_g(struct stuff **pps) { 87 *pps = my_malloc(sizeof(struct stuff)); // no-warning 88 (*pps)->somefield = my_malloc(42); // no-warning 89} 90 91void af2() { 92 int *p = my_malloc(12); 93 my_free(p); 94 free(p); // expected-warning{{Try to free a memory block that has been released}} 95} 96 97void af2b() { 98 int *p = my_malloc(12); 99 free(p); 100 my_free(p); // expected-warning{{Try to free a memory block that has been released}} 101} 102 103void af2c() { 104 int *p = my_malloc(12); 105 free(p); 106 my_hold(p); // expected-warning{{Try to free a memory block that has been released}} 107} 108 109void af2d() { 110 int *p = my_malloc(12); 111 free(p); 112 my_hold2(0, 0, p); // expected-warning{{Try to free a memory block that has been released}} 113} 114 115// No leak if malloc returns null. 116void af2e() { 117 int *p = my_malloc(12); 118 if (!p) 119 return; // no-warning 120 free(p); // no-warning 121} 122 123// This case would inflict a double-free elsewhere. 124// However, this case is considered an analyzer bug since it causes false-positives. 125void af3() { 126 int *p = my_malloc(12); 127 my_hold(p); 128 free(p); // no-warning 129} 130 131// This case would inflict a double-free elsewhere. 132// However, this case is considered an analyzer bug since it causes false-positives. 133int * af4() { 134 int *p = my_malloc(12); 135 my_free(p); 136 return p; // no-warning 137} 138 139// This case is (possibly) ok, be conservative 140int * af5() { 141 int *p = my_malloc(12); 142 my_hold(p); 143 return p; // no-warning 144} 145 146 147 148// This case tests that storing malloc'ed memory to a static variable which is 149// then returned is not leaked. In the absence of known contracts for functions 150// or inter-procedural analysis, this is a conservative answer. 151int *f3() { 152 static int *p = 0; 153 p = malloc(12); 154 return p; // no-warning 155} 156 157// This case tests that storing malloc'ed memory to a static global variable 158// which is then returned is not leaked. In the absence of known contracts for 159// functions or inter-procedural analysis, this is a conservative answer. 160static int *p_f4 = 0; 161int *f4() { 162 p_f4 = malloc(12); 163 return p_f4; // no-warning 164} 165 166int *f5() { 167 int *q = malloc(12); 168 q = realloc(q, 20); 169 return q; // no-warning 170} 171 172void f6() { 173 int *p = malloc(12); 174 if (!p) 175 return; // no-warning 176 else 177 free(p); 178} 179 180void f6_realloc() { 181 int *p = malloc(12); 182 if (!p) 183 return; // no-warning 184 else 185 realloc(p,0); 186} 187 188 189char *doit2(); 190void pr6069() { 191 char *buf = doit2(); 192 free(buf); 193} 194 195void pr6293() { 196 free(0); 197} 198 199void f7() { 200 char *x = (char*) malloc(4); 201 free(x); 202 x[0] = 'a'; // expected-warning{{Use dynamically allocated memory after it is freed.}} 203} 204 205void f7_realloc() { 206 char *x = (char*) malloc(4); 207 realloc(x,0); 208 x[0] = 'a'; // expected-warning{{Use dynamically allocated memory after it is freed.}} 209} 210 211void PR6123() { 212 int *x = malloc(11); // expected-warning{{Cast a region whose size is not a multiple of the destination type size.}} 213} 214 215void PR7217() { 216 int *buf = malloc(2); // expected-warning{{Cast a region whose size is not a multiple of the destination type size.}} 217 buf[1] = 'c'; // not crash 218} 219 220void mallocCastToVoid() { 221 void *p = malloc(2); 222 const void *cp = p; // not crash 223 free(p); 224} 225 226void mallocCastToFP() { 227 void *p = malloc(2); 228 void (*fp)() = p; // not crash 229 free(p); 230} 231 232// This tests that malloc() buffers are undefined by default 233char mallocGarbage () { 234 char *buf = malloc(2); 235 char result = buf[1]; // expected-warning{{undefined}} 236 free(buf); 237 return result; 238} 239 240// This tests that calloc() buffers need to be freed 241void callocNoFree () { 242 char *buf = calloc(2,2); 243 return; // expected-warning{{never released}} 244} 245 246// These test that calloc() buffers are zeroed by default 247char callocZeroesGood () { 248 char *buf = calloc(2,2); 249 char result = buf[3]; // no-warning 250 if (buf[1] == 0) { 251 free(buf); 252 } 253 return result; // no-warning 254} 255 256char callocZeroesBad () { 257 char *buf = calloc(2,2); 258 char result = buf[3]; // no-warning 259 if (buf[1] != 0) { 260 free(buf); // expected-warning{{never executed}} 261 } 262 return result; // expected-warning{{never released}} 263} 264