llvm-project/clang/test/Analysis/malloc.c

// RUN: %clang_cc1 -analyze -analyzer-experimental-internal-checks -analyzer-check-objc-mem -analyzer-experimental-checks -analyzer-store=region -verify %s
typedef __typeof(sizeof(int)) size_t;
void *malloc(size_t);
void free(void *);
void *realloc(void *ptr, size_t size);
void *calloc(size_t nmemb, size_t size);

void f1() {
  int *p = malloc(12);
  return; // expected-warning{{Allocated memory never released. Potential memory leak.}}
}

void f1_b() {
  int *p = malloc(12); // expected-warning{{Allocated memory never released. Potential memory leak.}}
}

void f2() {
  int *p = malloc(12);
  free(p);
  free(p); // expected-warning{{Try to free a memory block that has been released}}
}

// This case tests that storing malloc'ed memory to a static variable which is
// then returned is not leaked.  In the absence of known contracts for functions
// or inter-procedural analysis, this is a conservative answer.
int *f3() {
  static int *p = 0;
  p = malloc(12); 
  return p; // no-warning
}

// This case tests that storing malloc'ed memory to a static global variable
// which is then returned is not leaked.  In the absence of known contracts for
// functions or inter-procedural analysis, this is a conservative answer.
static int *p_f4 = 0;
int *f4() {
  p_f4 = malloc(12); 
  return p_f4; // no-warning
}

int *f5() {
  int *q = malloc(12);
  q = realloc(q, 20);
  return q; // no-warning
}

void f6() {
  int *p = malloc(12);
  if (!p)
    return; // no-warning
  else
    free(p);
}

char *doit2();
void pr6069() {
  char *buf = doit2();
  free(buf);
}

void pr6293() {
  free(0);
}

void f7() {
  char *x = (char*) malloc(4);
  free(x);
  x[0] = 'a'; // expected-warning{{Use dynamically allocated memory after it is freed.}}
}

void PR6123() {
  int *x = malloc(11); // expected-warning{{Cast a region whose size is not a multiple of the destination type size.}}
}

void PR7217() {
  int *buf = malloc(2); // expected-warning{{Cast a region whose size is not a multiple of the destination type size.}}
  buf[1] = 'c'; // not crash
}

void mallocCastToVoid() {
  void *p = malloc(2);
  const void *cp = p; // not crash
  free(p);
}

void mallocCastToFP() {
  void *p = malloc(2);
  void (*fp)() = p; // not crash
  free(p);
}

// This tests that malloc() buffers are undefined by default
char mallocGarbage () {
	char *buf = malloc(2);
	char result = buf[1]; // expected-warning{{undefined}}
	free(buf);
	return result;
}

// This tests that calloc() buffers need to be freed
void callocNoFree () {
  char *buf = calloc(2,2);
  return; // expected-warning{{never released}}
}

// These test that calloc() buffers are zeroed by default
char callocZeroesGood () {
	char *buf = calloc(2,2);
	char result = buf[3]; // no-warning
	if (buf[1] == 0) {
	  free(buf);
	}
	return result; // no-warning
}

char callocZeroesBad () {
	char *buf = calloc(2,2);
	char result = buf[3]; // no-warning
	if (buf[1] != 0) {
	  free(buf);
	}
	return result; // expected-warning{{never released}}
}