project-base/server-skynet-source-3rd-jemalloc
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Avoid variable length arrays and remove declarations within code

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MSVC doesn't support C99, and building as C++ to be able to use them is
dangerous, as C++ and C99 are incompatible.

Introduce a VARIABLE_ARRAY macro that either uses VLA when supported,
or alloca() otherwise. Note that using alloca() inside loops doesn't
quite work like VLAs, thus the use of VARIABLE_ARRAY there is discouraged.
It might be worth investigating ways to check whether VARIABLE_ARRAY is
used in such context at runtime in debug builds and bail out if that
happens.
This commit is contained in:
Mike Hommey
2012-04-24 23:22:02 +02:00
committed by Jason Evans
parent f278994029
commit 8b49971d0c
7 changed files with 43 additions and 18 deletions
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18
src/arena.c
View File

@@ -640,14 +640,14 @@ arena_chunk_purge(arena_t *arena, arena_chunk_t *chunk)
if (mapelm->bits & CHUNK_MAP_LARGE)
pageind += mapelm->bits >> LG_PAGE;
else {
size_t binind;
arena_bin_info_t *bin_info;
arena_run_t *run = (arena_run_t *)((uintptr_t)
chunk + (uintptr_t)(pageind << LG_PAGE));
assert((mapelm->bits >> LG_PAGE) == 0);
size_t binind = arena_bin_index(arena,
run->bin);
arena_bin_info_t *bin_info =
&arena_bin_info[binind];
binind = arena_bin_index(arena, run->bin);
bin_info = &arena_bin_info[binind];
pageind += bin_info->run_size >> LG_PAGE;
}
}
@@ -1056,11 +1056,12 @@ arena_bin_runs_first(arena_bin_t *bin)
if (mapelm != NULL) {
arena_chunk_t *chunk;
size_t pageind;
arena_run_t *run;
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(mapelm);
pageind = ((((uintptr_t)mapelm - (uintptr_t)chunk->map) /
sizeof(arena_chunk_map_t))) + map_bias;
arena_run_t *run = (arena_run_t *)((uintptr_t)chunk +
run = (arena_run_t *)((uintptr_t)chunk +
(uintptr_t)((pageind - (mapelm->bits >> LG_PAGE)) <<
LG_PAGE));
return (run);
@@ -1596,14 +1597,15 @@ arena_dalloc_bin(arena_t *arena, arena_chunk_t *chunk, void *ptr,
size_t pageind;
arena_run_t *run;
arena_bin_t *bin;
size_t size;
arena_bin_info_t *bin_info;
size_t size, binind;
pageind = ((uintptr_t)ptr - (uintptr_t)chunk) >> LG_PAGE;
run = (arena_run_t *)((uintptr_t)chunk + (uintptr_t)((pageind -
(mapelm->bits >> LG_PAGE)) << LG_PAGE));
bin = run->bin;
size_t binind = arena_bin_index(arena, bin);
arena_bin_info_t *bin_info = &arena_bin_info[binind];
binind = arena_bin_index(arena, bin);
bin_info = &arena_bin_info[binind];
if (config_fill || config_stats)
size = bin_info->reg_size;

4
src/ctl.c
View File

@@ -520,7 +520,7 @@ static void
ctl_refresh(void)
{
unsigned i;
arena_t *tarenas[narenas];
VARIABLE_ARRAY(arena_t *, tarenas, narenas);
if (config_stats) {
malloc_mutex_lock(&chunks_mtx);
@@ -1232,7 +1232,7 @@ arenas_purge_ctl(const size_t *mib, size_t miblen, void *oldp, size_t *oldlenp,
ret = EFAULT;
goto label_return;
} else {
arena_t *tarenas[narenas];
VARIABLE_ARRAY(arena_t *, tarenas, narenas);
malloc_mutex_lock(&arenas_lock);
memcpy(tarenas, arenas, sizeof(arena_t *) * narenas);

4
src/stats.c
View File

@@ -498,7 +498,7 @@ stats_print(void (*write_cb)(void *, const char *), void *cbopaque,
CTL_GET("arenas.narenas", &narenas, unsigned);
{
bool initialized[narenas];
VARIABLE_ARRAY(bool, initialized, narenas);
size_t isz;
unsigned i, ninitialized;
@@ -527,7 +527,7 @@ stats_print(void (*write_cb)(void *, const char *), void *cbopaque,
CTL_GET("arenas.narenas", &narenas, unsigned);
{
bool initialized[narenas];
VARIABLE_ARRAY(bool, initialized, narenas);
size_t isz;
unsigned i;

2
src/tsd.c
View File

@@ -36,7 +36,7 @@ JEMALLOC_ATTR(visibility("default"))
void
_malloc_thread_cleanup(void)
{
bool pending[ncleanups], again;
bool pending[MALLOC_TSD_CLEANUPS_MAX], again;
unsigned i;
for (i = 0; i < ncleanups; i++)