wuggy/Dactyloidae
wuggy/Dactyloidae
1
0
Fork 0
mirror of https://repo.dactyloidae.xyz/Dactyloidae/UXP.git synced 2026-09-29 11:57:32 +09:00
Code Issues Projects Releases Packages Wiki Activity

Issue #1307 - Part 4: Stop using variable-length arrays.

Browse source 
"USING VLA'S IS ACTIVELY STUPID! It generates much more code, and much
slower code (and more fragile code), than just using a fixed key size
would have done." -- Linus Torvalds
This commit is contained in:
wolfbeast 2019-11-30 15:42:59 +01:00 • committed by Roy Tam
commit 442f6b3252
2 changed files with 20 additions and 38 deletions
Download patch file Download diff file Expand all files Collapse all files

4
memory/mozjemalloc/jemalloc.c
View file

@ -381,10 +381,6 @@ void *_mmap(void *addr, size_t length, int prot, int flags,
#define __DECONST(type, var) ((type)(uintptr_t)(const void *)(var))
#endif
#ifdef MOZ_MEMORY_WINDOWS
/* MSVC++ does not support C99 variable-length arrays. */
# define RB_NO_C99_VARARRAYS
#endif
#include "rb.h"
#ifdef MALLOC_DEBUG

54
memory/mozjemalloc/rb.h
View file

@ -36,7 +36,6 @@
* (Optional.)
* #define SIZEOF_PTR ...
* #define SIZEOF_PTR_2POW ...
* #define RB_NO_C99_VARARRAYS
*
* (Optional, see assert(3).)
* #define NDEBUG
@ -769,39 +768,26 @@ a_prefix##remove(a_tree_type *tree, a_type *node) { \
* effort.
*/
#ifdef RB_NO_C99_VARARRAYS
/*
* Avoid using variable-length arrays, at the cost of using more stack space.
* Size the path arrays such that they are always large enough, even if a
* tree consumes all of memory. Since each node must contain a minimum of
* two pointers, there can never be more nodes than:
*
* 1 << ((SIZEOF_PTR<<3) - (SIZEOF_PTR_2POW+1))
*
* Since the depth of a tree is limited to 3*lg(#nodes), the maximum depth
* is:
*
* (3 * ((SIZEOF_PTR<<3) - (SIZEOF_PTR_2POW+1)))
*
* This works out to a maximum depth of 87 and 180 for 32- and 64-bit
* systems, respectively (approximatly 348 and 1440 bytes, respectively).
*/
# define rbp_compute_f_height(a_type, a_field, a_tree)
# define rbp_f_height (3 * ((SIZEOF_PTR<<3) - (SIZEOF_PTR_2POW+1)))
# define rbp_compute_fr_height(a_type, a_field, a_tree)
# define rbp_fr_height (3 * ((SIZEOF_PTR<<3) - (SIZEOF_PTR_2POW+1)))
#else
# define rbp_compute_f_height(a_type, a_field, a_tree) \
/* Compute the maximum possible tree depth (3X the black height). */\
unsigned rbp_f_height; \
rbp_black_height(a_type, a_field, a_tree, rbp_f_height); \
rbp_f_height *= 3;
# define rbp_compute_fr_height(a_type, a_field, a_tree) \
/* Compute the maximum possible tree depth (3X the black height). */\
unsigned rbp_fr_height; \
rbp_black_height(a_type, a_field, a_tree, rbp_fr_height); \
rbp_fr_height *= 3;
#endif
/*
* Avoid using variable-length arrays.
* Size the path arrays such that they are always large enough, even if a
* tree consumes all of memory. Since each node must contain a minimum of
* two pointers, there can never be more nodes than:
*
* 1 << ((SIZEOF_PTR<<3) - (SIZEOF_PTR_2POW+1))
*
* Since the depth of a tree is limited to 3*lg(#nodes), the maximum depth
* is:
*
* (3 * ((SIZEOF_PTR<<3) - (SIZEOF_PTR_2POW+1)))
*
* This works out to a maximum depth of 87 and 180 for 32- and 64-bit
* systems, respectively (approximatly 348 and 1440 bytes, respectively).
*/
#define rbp_compute_f_height(a_type, a_field, a_tree)
#define rbp_f_height (3 * ((SIZEOF_PTR<<3) - (SIZEOF_PTR_2POW+1)))
#define rbp_compute_fr_height(a_type, a_field, a_tree)
#define rbp_fr_height (3 * ((SIZEOF_PTR<<3) - (SIZEOF_PTR_2POW+1)))
#define rb_foreach_begin(a_type, a_field, a_tree, a_var) { \
rbp_compute_f_height(a_type, a_field, a_tree) \