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Merge branch 'ebassi/aligned-alloc' into 'main'

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Add aligned memory allocators

Closes #2574

See merge request GNOME/glib!2421
This commit is contained in:
Philip Withnall 2022-02-11 15:04:25 +00:00
commit f9c08308ea
6 changed files with 305 additions and 4 deletions
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5
docs/reference/glib/glib-sections.txt
View File

@ -1393,6 +1393,11 @@ g_alloca0
g_newa
g_newa0
<SUBSECTION>
g_aligned_alloc
g_aligned_alloc0
g_aligned_free
<SUBSECTION>
g_memmove
g_memdup

157
glib/gmem.c
View File

@ -30,6 +30,25 @@
#include "gmem.h"
#if defined(HAVE_POSIX_MEMALIGN) && !defined(_XOPEN_SOURCE)
# define _XOPEN_SOURCE 600
#endif
#if defined(HAVE_MEMALIGN) || defined(HAVE__ALIGNED_MALLOC)
/* Required for _aligned_malloc() and _aligned_free() on Windows */
#include <malloc.h>
#endif
#ifdef HAVE__ALIGNED_MALLOC
/* _aligned_malloc() takes parameters of aligned_malloc() in reverse order */
# define aligned_alloc(alignment, size) _aligned_malloc (size, alignment)
/* _aligned_malloc()'ed memory must be freed by _align_free() on MSVC */
# define aligned_free(x) _aligned_free (x)
#else
# define aligned_free(x) free (x)
#endif
#include <stdlib.h>
#include <string.h>
#include <signal.h>
@ -522,3 +541,141 @@ g_mem_profile (void)
{
g_warning (G_STRLOC ": memory profiling not supported");
}
/**
* g_aligned_alloc:
* @n_blocks: the number of blocks to allocate
* @n_block_bytes: the size of each block in bytes
* @alignment: the alignment to be enforced, which must be a positive power of 2
* and a multiple of `sizeof(void*)`
*
* This function is similar to g_malloc(), allocating (@n_blocks * @n_block_bytes)
* bytes, but care is taken to align the allocated memory to with the given
* alignment value. Additionally, it will detect possible overflow during
* multiplication.
*
* Aligned memory allocations returned by this function can only be
* freed using g_aligned_free().
*
* Returns: (transfer full): the allocated memory
*
* Since: 2.72
*/
gpointer
g_aligned_alloc (gsize n_blocks,
gsize n_block_bytes,
gsize alignment)
{
gpointer res = NULL;
gsize real_size;
if (G_UNLIKELY ((alignment == 0) || (alignment & (alignment - 1)) != 0))
{
g_error ("%s: alignment %"G_GSIZE_FORMAT" must be a positive power of two",
G_STRLOC, alignment);
}
if (G_UNLIKELY ((alignment % sizeof (void *)) != 0))
{
g_error ("%s: alignment %"G_GSIZE_FORMAT" must be a multiple of %"G_GSIZE_FORMAT,
G_STRLOC, alignment, sizeof (void *));
}
if (SIZE_OVERFLOWS (n_blocks, n_block_bytes))
{
g_error ("%s: overflow allocating %"G_GSIZE_FORMAT"*%"G_GSIZE_FORMAT" bytes",
G_STRLOC, n_blocks, n_block_bytes);
}
real_size = n_blocks * n_block_bytes;
if (G_UNLIKELY (real_size == 0))
{
TRACE(GLIB_MEM_ALLOC((void*) NULL, (int) real_size, 0, 0));
return NULL;
}
/* We need to clear errno because posix_memalign() will use its return
* value in the same way memalign() and aligned_alloc() will set errno.
* Additionally, posix_memalign() will warn if its return value is left
* unassigned.
*
* We handle all possible return values (ENOMEM and EINVAL) with either
* precondition or postcondition checking.
*/
errno = 0;
#if defined(HAVE_POSIX_MEMALIGN)
errno = posix_memalign (&res, alignment, real_size);
#elif defined(HAVE_ALIGNED_ALLOC) || defined(HAVE__ALIGNED_MALLOC)
/* real_size must be a multiple of alignment */
if (real_size % alignment != 0)
{
gsize offset = real_size % alignment;
if (G_MAXSIZE - real_size < (alignment - offset))
{
g_error ("%s: overflow allocating %"G_GSIZE_FORMAT"+%"G_GSIZE_FORMAT" bytes",
G_STRLOC, real_size, (alignment - offset));
}
real_size += (alignment - offset);
}
res = aligned_alloc (alignment, real_size);
#elif defined(HAVE_MEMALIGN)
res = memalign (alignment, real_size);
#else
# error "This platform does not have an aligned memory allocator."
#endif
TRACE (GLIB_MEM_ALLOC((void*) res, (unsigned int) real_size, 0, 0));
if (res)
return res;
g_error ("%s: failed to allocate %"G_GSIZE_FORMAT" bytes",
G_STRLOC, real_size);
return NULL;
}
/**
* g_aligned_alloc0:
* @n_blocks: the number of blocks to allocate
* @n_block_bytes: the size of each block in bytes
* @alignment: the alignment to be enforced, which must be a positive power of 2
* and a multiple of `sizeof(void*)`
*
* This function is similar to g_aligned_alloc(), but it will
* also clear the allocated memory before returning it.
*
* Returns: (transfer full): the allocated, cleared memory
*
* Since: 2.72
*/
gpointer
g_aligned_alloc0 (gsize n_blocks,
gsize n_block_bytes,
gsize alignment)
{
gpointer res = g_aligned_alloc (n_blocks, n_block_bytes, alignment);
if (G_LIKELY (res != NULL))
memset (res, 0, n_blocks * n_block_bytes);
return res;
}
/**
* g_aligned_free:
* @mem: (nullable): the memory to deallocate
*
* Frees the memory allocated by g_aligned_alloc().
*
* Since: 2.72
*/
void
g_aligned_free (gpointer mem)
{
aligned_free (mem);
}

11
glib/gmem.h
View File

@ -111,6 +111,17 @@ gpointer g_try_realloc_n (gpointer mem,
gsize n_blocks,
gsize n_block_bytes) G_GNUC_WARN_UNUSED_RESULT;
GLIB_AVAILABLE_IN_2_72
gpointer g_aligned_alloc (gsize n_blocks,
gsize n_block_bytes,
gsize alignment) G_GNUC_WARN_UNUSED_RESULT G_GNUC_ALLOC_SIZE2(1,2);
GLIB_AVAILABLE_IN_2_72
gpointer g_aligned_alloc0 (gsize n_blocks,
gsize n_block_bytes,
gsize alignment) G_GNUC_WARN_UNUSED_RESULT G_GNUC_ALLOC_SIZE2(1,2);
GLIB_AVAILABLE_IN_2_72
void g_aligned_free (gpointer mem);
#if defined(glib_typeof) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_58
#define g_clear_pointer(pp, destroy) \
G_STMT_START \

21
glib/tests/mem-overflow.c
View File

@ -34,13 +34,14 @@ static gsize a = G_MAXSIZE / 10 + 10;
static gsize b = 10;
typedef char X[10];
#define MEM_OVERFLOW_TEST(name, code) \
#define MEM_OVERFLOW_TEST(name, code) MEM_OVERFLOW_TEST_FULL(name, code, g_free)
#define MEM_OVERFLOW_TEST_FULL(name, code, free_func) \
static void \
mem_overflow_ ## name (void) \
{ \
gpointer p; \
code; \
g_free (p); \
free_func (p); \
exit (0); \
}
@ -68,6 +69,12 @@ MEM_OVERFLOW_TEST (new0_b, p = g_new0 (X, b))
MEM_OVERFLOW_TEST (renew_a, p = g_malloc (1); p = g_renew (X, p, a))
MEM_OVERFLOW_TEST (renew_b, p = g_malloc (1); p = g_renew (X, p, b))
MEM_OVERFLOW_TEST_FULL (aligned_alloc_a, p = g_aligned_alloc (sizeof(X), a, 16), g_aligned_free)
MEM_OVERFLOW_TEST_FULL (aligned_alloc_b, p = g_aligned_alloc (sizeof(X), b, 16), g_aligned_free)
MEM_OVERFLOW_TEST_FULL (aligned_alloc0_a, p = g_aligned_alloc0 (sizeof(X), a, 16), g_aligned_free)
MEM_OVERFLOW_TEST_FULL (aligned_alloc0_b, p = g_aligned_alloc0 (sizeof(X), b, 16), g_aligned_free)
static void
mem_overflow_malloc_0 (void)
{
@ -171,6 +178,12 @@ mem_overflow (void)
CHECK_SUBPROCESS_PASS (malloc_0);
CHECK_SUBPROCESS_PASS (realloc_0);
CHECK_SUBPROCESS_FAIL (aligned_alloc_a);
CHECK_SUBPROCESS_PASS (aligned_alloc_b);
CHECK_SUBPROCESS_FAIL (aligned_alloc0_a);
CHECK_SUBPROCESS_PASS (aligned_alloc0_b);
}
#ifdef __GNUC__
@ -231,6 +244,10 @@ main (int argc,
g_test_add_func ("/mem/overflow/subprocess/renew_b", mem_overflow_renew_b);
g_test_add_func ("/mem/overflow/subprocess/malloc_0", mem_overflow_malloc_0);
g_test_add_func ("/mem/overflow/subprocess/realloc_0", mem_overflow_realloc_0);
g_test_add_func ("/mem/overflow/subprocess/aligned_alloc_a", mem_overflow_aligned_alloc_a);
g_test_add_func ("/mem/overflow/subprocess/aligned_alloc_b", mem_overflow_aligned_alloc_b);
g_test_add_func ("/mem/overflow/subprocess/aligned_alloc0_a", mem_overflow_aligned_alloc0_a);
g_test_add_func ("/mem/overflow/subprocess/aligned_alloc0_b", mem_overflow_aligned_alloc0_b);
#ifdef __GNUC__
g_test_add_func ("/mem/empty-alloc", empty_alloc);

100
glib/tests/utils.c
View File

@ -915,6 +915,100 @@ test_misc_mem (void)
g_assert (a == NULL);
}
static void
aligned_alloc_nz (void)
{
gpointer a;
/* Test an alignment that’s zero */
a = g_aligned_alloc (16, sizeof(char), 0);
g_assert_null (a);
exit (0);
}
static void
aligned_alloc_npot (void)
{
gpointer a;
/* Test an alignment that’s not a power of two */
a = g_aligned_alloc (16, sizeof(char), 15);
g_assert_null (a);
exit (0);
}
static void
aligned_alloc_nmov (void)
{
gpointer a;
/* Test an alignment that’s not a multiple of sizeof(void*) */
a = g_aligned_alloc (16, sizeof(char), 4);
g_assert_null (a);
exit (0);
}
static void
test_aligned_mem (void)
{
gpointer a;
g_test_summary ("Aligned memory allocator");
a = g_aligned_alloc (0, sizeof(int), 8);
g_assert_null (a);
a = g_aligned_alloc0 (0, sizeof(int), 8);
g_assert_null (a);
a = g_aligned_alloc (16, 0, 8);
g_assert_null (a);
#define CHECK_SUBPROCESS_FAIL(name,msg) do { \
{ \
g_test_message (msg); \
g_test_trap_subprocess ("/utils/aligned-mem/subprocess/" #name, 0, 0); \
g_test_trap_assert_failed (); \
} \
} while (0)
CHECK_SUBPROCESS_FAIL (aligned_alloc_nz, "Alignment must not be zero");
CHECK_SUBPROCESS_FAIL (aligned_alloc_npot, "Alignment must be a power of two");
CHECK_SUBPROCESS_FAIL (aligned_alloc_nmov, "Alignment must be a multiple of sizeof(void*)");
}
static void
test_aligned_mem_alignment (void)
{
gchar *p;
g_test_summary ("Check that g_aligned_alloc() returns a correctly aligned pointer");
p = g_aligned_alloc (5, sizeof (*p), 256);
g_assert_nonnull (p);
g_assert_cmpuint (((guintptr) p) % 256, ==, 0);
g_aligned_free (p);
}
static void
test_aligned_mem_zeroed (void)
{
gsize n_blocks = 10;
guint *p;
gsize i;
g_test_summary ("Check that g_aligned_alloc0() zeroes out its allocation");
p = g_aligned_alloc0 (n_blocks, sizeof (*p), 16);
g_assert_nonnull (p);
for (i = 0; i < n_blocks; i++)
g_assert_cmpuint (p[i], ==, 0);
g_aligned_free (p);
}
static void
test_nullify (void)
{
@ -1084,6 +1178,12 @@ main (int argc,
g_test_add_func ("/utils/take-pointer", test_take_pointer);
g_test_add_func ("/utils/clear-source", test_clear_source);
g_test_add_func ("/utils/misc-mem", test_misc_mem);
g_test_add_func ("/utils/aligned-mem", test_aligned_mem);
g_test_add_func ("/utils/aligned-mem/subprocess/aligned_alloc_nz", aligned_alloc_nz);
g_test_add_func ("/utils/aligned-mem/subprocess/aligned_alloc_npot", aligned_alloc_npot);
g_test_add_func ("/utils/aligned-mem/subprocess/aligned_alloc_nmov", aligned_alloc_nmov);
g_test_add_func ("/utils/aligned-mem/alignment", test_aligned_mem_alignment);
g_test_add_func ("/utils/aligned-mem/zeroed", test_aligned_mem_zeroed);
g_test_add_func ("/utils/nullify", test_nullify);
g_test_add_func ("/utils/atexit", test_atexit);
g_test_add_func ("/utils/check-setuid", test_check_setuid);

15
meson.build
View File

@ -653,8 +653,19 @@ if host_system == 'android'
endif
# Check that posix_memalign() is usable; must use header
if host_system != 'windows' and cc.has_function('posix_memalign', prefix : '#include <stdlib.h>')
if cc.has_function('memalign', prefix: '#include <stdlib.h>\n#include <malloc.h>')
glib_conf.set('HAVE_MEMALIGN', 1)
endif
if cc.has_function('_aligned_malloc', prefix: '#include <malloc.h>')
glib_conf.set('HAVE__ALIGNED_MALLOC', 1)
endif
if host_system != 'windows' and cc.has_function('aligned_alloc', prefix: '#include <stdlib.h>')
glib_conf.set('HAVE_ALIGNED_ALLOC', 1)
endif
if host_system != 'windows' and cc.has_function('posix_memalign', prefix: '#include <stdlib.h>')
glib_conf.set('HAVE_POSIX_MEMALIGN', 1)
endif