Viewing file:  malloc-callbacks.c (1.92 KB) -rw-r--r--
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#include <stdlib.h>
typedef void *(*allocator_t) (size_t);
typedef void (*deallocator_t) (void *);
static allocator_t __attribute__((noinline))
get_malloc (void)
{
return malloc;
}
static allocator_t __attribute__((noinline))
get_alloca (void)
{
/* On e.g. Solaris, alloca is a macro so we can't take its address;
use __builtin_alloca instead. */
return __builtin_alloca;
}
static deallocator_t __attribute__((noinline))
get_free (void)
{
return free;
}
void test_1 (void *ptr)
{
deallocator_t dealloc_fn = free;
dealloc_fn (ptr); /* { dg-message "first 'free' here" } */
dealloc_fn (ptr); /* { dg-warning "double-'free'" } */
}
void test_2 (void *ptr)
{
deallocator_t dealloc_fn = get_free ();
dealloc_fn (ptr); /* { dg-message "first 'free' here" } */
dealloc_fn (ptr); /* { dg-warning "double-'free'" } */
}
static void __attribute__((noinline))
called_by_test_3 (void *ptr, deallocator_t dealloc_fn)
{
dealloc_fn (ptr); /* { dg-warning "double-'free'" } */
}
void test_3 (void *ptr)
{
called_by_test_3 (ptr, free);
called_by_test_3 (ptr, free);
}
int *test_4 (void)
{
allocator_t alloc_fn = get_malloc ();
int *ptr = alloc_fn (sizeof (int)); /* { dg-message "this call could return NULL" } */
*ptr = 42; /* { dg-warning "dereference of possibly-NULL 'ptr'" } */
return ptr;
}
int *test_5 (void)
{
allocator_t alloc_fn = get_alloca ();
deallocator_t dealloc_fn = get_free ();
int *ptr = alloc_fn (sizeof (int)); /* dg-message "region created on stack here" } */
dealloc_fn (ptr); /* { dg-warning "'free' of 'ptr' which points to memory on the stack" } */
}
static void __attribute__((noinline))
called_by_test_6a (void *ptr)
{
free (ptr); /* { dg-warning "double-'free'" } */
}
static deallocator_t __attribute__((noinline))
called_by_test_6b (void)
{
return called_by_test_6a;
}
void test_6 (void *ptr)
{
deallocator_t dealloc_fn = called_by_test_6b ();
dealloc_fn (ptr);
dealloc_fn (ptr);
}
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