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Make the behavior of malloc(0) standards-compliant by getting rid of nil,

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and instead creating a small allocation for each malloc(0) call.  The
optional SysV compatibility behavior remains unchanged.

Add a couple of assertions.

Fix a couple of typos in error message strings.
This commit is contained in:
Jason Evans 2006-06-30 20:54:15 +00:00
parent 732be1f298
commit 00d8242c2b
1 changed files with 52 additions and 54 deletions
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50
lib/libc/stdlib/malloc.c
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@ -659,9 +659,6 @@ struct arena_s {
* Data.
*/
/* Used as a special "nil" return value for malloc(0). */
static const int nil;
/* Number of CPUs. */
static unsigned ncpus;
@ -1642,6 +1639,7 @@ arena_run_reg_dalloc(arena_run_t *run, arena_bin_t *bin, void *ptr, size_t size)
#undef POW2_CASE
#undef QUANTUM_CASE
assert(regind < bin->nregs);
assert(regind * size == diff);
elm = regind >> (SIZEOF_INT_2POW + 3);
if (elm < run->regs_minelm)
@ -2239,7 +2237,6 @@ arena_salloc(const void *ptr)
arena_chunk_map_t mapelm;
assert(ptr != NULL);
assert(ptr != &nil);
assert(CHUNK_ADDR2BASE(ptr) != ptr);
/*
@ -2320,7 +2317,6 @@ arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr)
assert(arena->magic == ARENA_MAGIC);
assert(chunk->arena == arena);
assert(ptr != NULL);
assert(ptr != &nil);
assert(CHUNK_ADDR2BASE(ptr) != ptr);
pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow);
@ -2353,6 +2349,7 @@ arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr)
/* Medium allocation. */
size = mapelm.npages << pagesize_2pow;
assert((((uintptr_t)ptr) & (size - 1)) == 0);
if (opt_junk)
memset(ptr, 0x5a, size);
@ -2815,7 +2812,6 @@ isalloc(const void *ptr)
arena_chunk_t *chunk;
assert(ptr != NULL);
assert(ptr != &nil);
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
if (chunk != ptr) {
@ -2850,7 +2846,6 @@ iralloc(void *ptr, size_t size)
size_t oldsize;
assert(ptr != NULL);
assert(ptr != &nil);
assert(size != 0);
oldsize = isalloc(ptr);
@ -2869,7 +2864,6 @@ idalloc(void *ptr)
arena_chunk_t *chunk;
assert(ptr != NULL);
assert(ptr != &nil);
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
if (chunk != ptr) {
@ -3404,11 +3398,12 @@ malloc(size_t size)
if (size == 0) {
if (opt_sysv == false)
ret = (void *)&nil;
else
size = 1;
else {
ret = NULL;
goto RETURN;
}
}
ret = imalloc(size);
@ -3486,10 +3481,11 @@ calloc(size_t num, size_t size)
num_size = num * size;
if (num_size == 0) {
if (opt_sysv == false)
ret = (void *)&nil;
else
num_size = 1;
else {
ret = NULL;
goto RETURN;
}
/*
* Try to avoid division here. We know that it isn't possible to
* overflow during multiplication if neither operand uses any of the
@ -3524,8 +3520,18 @@ realloc(void *ptr, size_t size)
{
void *ret;
if (size != 0) {
if (ptr != &nil && ptr != NULL) {
if (size == 0) {
if (opt_sysv == false)
size = 1;
else {
if (ptr != NULL)
idalloc(ptr);
ret = NULL;
goto RETURN;
}
}
if (ptr != NULL) {
assert(malloc_initialized);
ret = iralloc(ptr, size);
@ -3533,7 +3539,7 @@ realloc(void *ptr, size_t size)
if (ret == NULL) {
if (opt_xmalloc) {
malloc_printf("%s: (malloc) Error in"
" ralloc(%p, %zu): out of memory\n",
" realloc(%p, %zu): out of memory\n",
_getprogname(), ptr, size);
abort();
}
@ -3548,20 +3554,15 @@ realloc(void *ptr, size_t size)
if (ret == NULL) {
if (opt_xmalloc) {
malloc_printf("%s: (malloc) Error in"
" ralloc(%p, %zu): out of memory\n",
" realloc(%p, %zu): out of memory\n",
_getprogname(), ptr, size);
abort();
}
errno = ENOMEM;
}
}
} else {
if (ptr != &nil && ptr != NULL)
idalloc(ptr);
ret = (void *)&nil;
}
RETURN:
UTRACE(ptr, size, ret);
return (ret);
}
@ -3571,7 +3572,7 @@ free(void *ptr)
{
UTRACE(ptr, 0, 0);
if (ptr != &nil && ptr != NULL) {
if (ptr != NULL) {
assert(malloc_initialized);
idalloc(ptr);
@ -3592,9 +3593,6 @@ malloc_usable_size(const void *ptr)
assert(ptr != NULL);
if (ptr == &nil)
return (0);
else
return (isalloc(ptr));
}