Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 1 | /* |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 2 | ** $Id: lmem.c $ |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 3 | ** Interface to Memory Manager |
| 4 | ** See Copyright Notice in lua.h |
| 5 | */ |
| 6 | |
| 7 | #define lmem_c |
| 8 | #define LUA_CORE |
| 9 | |
| 10 | #include "lprefix.h" |
| 11 | |
| 12 | |
| 13 | #include <stddef.h> |
| 14 | |
| 15 | #include "lua.h" |
| 16 | |
| 17 | #include "ldebug.h" |
| 18 | #include "ldo.h" |
| 19 | #include "lgc.h" |
| 20 | #include "lmem.h" |
| 21 | #include "lobject.h" |
| 22 | #include "lstate.h" |
| 23 | |
| 24 | |
Tony Mak | 86713e6 | 2020-10-12 14:27:10 +0100 | [diff] [blame] | 25 | #if defined(EMERGENCYGCTESTS) |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 26 | /* |
| 27 | ** First allocation will fail whenever not building initial state |
| 28 | ** and not shrinking a block. (This fail will trigger 'tryagain' and |
| 29 | ** a full GC cycle at every allocation.) |
| 30 | */ |
| 31 | static void *firsttry (global_State *g, void *block, size_t os, size_t ns) { |
| 32 | if (ttisnil(&g->nilvalue) && ns > os) |
| 33 | return NULL; /* fail */ |
| 34 | else /* normal allocation */ |
| 35 | return (*g->frealloc)(g->ud, block, os, ns); |
| 36 | } |
| 37 | #else |
| 38 | #define firsttry(g,block,os,ns) ((*g->frealloc)(g->ud, block, os, ns)) |
| 39 | #endif |
| 40 | |
| 41 | |
| 42 | |
| 43 | |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 44 | |
| 45 | /* |
| 46 | ** About the realloc function: |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 47 | ** void *frealloc (void *ud, void *ptr, size_t osize, size_t nsize); |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 48 | ** ('osize' is the old size, 'nsize' is the new size) |
| 49 | ** |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 50 | ** - frealloc(ud, p, x, 0) frees the block 'p' and returns NULL. |
| 51 | ** Particularly, frealloc(ud, NULL, 0, 0) does nothing, |
| 52 | ** which is equivalent to free(NULL) in ISO C. |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 53 | ** |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 54 | ** - frealloc(ud, NULL, x, s) creates a new block of size 's' |
| 55 | ** (no matter 'x'). Returns NULL if it cannot create the new block. |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 56 | ** |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 57 | ** - otherwise, frealloc(ud, b, x, y) reallocates the block 'b' from |
| 58 | ** size 'x' to size 'y'. Returns NULL if it cannot reallocate the |
| 59 | ** block to the new size. |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 60 | */ |
| 61 | |
| 62 | |
| 63 | |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 64 | |
| 65 | /* |
| 66 | ** {================================================================== |
| 67 | ** Functions to allocate/deallocate arrays for the Parser |
| 68 | ** =================================================================== |
| 69 | */ |
| 70 | |
| 71 | /* |
| 72 | ** Minimum size for arrays during parsing, to avoid overhead of |
| 73 | ** reallocating to size 1, then 2, and then 4. All these arrays |
| 74 | ** will be reallocated to exact sizes or erased when parsing ends. |
| 75 | */ |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 76 | #define MINSIZEARRAY 4 |
| 77 | |
| 78 | |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 79 | void *luaM_growaux_ (lua_State *L, void *block, int nelems, int *psize, |
| 80 | int size_elems, int limit, const char *what) { |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 81 | void *newblock; |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 82 | int size = *psize; |
| 83 | if (nelems + 1 <= size) /* does one extra element still fit? */ |
| 84 | return block; /* nothing to be done */ |
| 85 | if (size >= limit / 2) { /* cannot double it? */ |
| 86 | if (unlikely(size >= limit)) /* cannot grow even a little? */ |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 87 | luaG_runerror(L, "too many %s (limit is %d)", what, limit); |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 88 | size = limit; /* still have at least one free place */ |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 89 | } |
| 90 | else { |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 91 | size *= 2; |
| 92 | if (size < MINSIZEARRAY) |
| 93 | size = MINSIZEARRAY; /* minimum size */ |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 94 | } |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 95 | lua_assert(nelems + 1 <= size && size <= limit); |
| 96 | /* 'limit' ensures that multiplication will not overflow */ |
| 97 | newblock = luaM_saferealloc_(L, block, cast_sizet(*psize) * size_elems, |
| 98 | cast_sizet(size) * size_elems); |
| 99 | *psize = size; /* update only when everything else is OK */ |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 100 | return newblock; |
| 101 | } |
| 102 | |
| 103 | |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 104 | /* |
| 105 | ** In prototypes, the size of the array is also its number of |
| 106 | ** elements (to save memory). So, if it cannot shrink an array |
| 107 | ** to its number of elements, the only option is to raise an |
| 108 | ** error. |
| 109 | */ |
| 110 | void *luaM_shrinkvector_ (lua_State *L, void *block, int *size, |
| 111 | int final_n, int size_elem) { |
| 112 | void *newblock; |
| 113 | size_t oldsize = cast_sizet((*size) * size_elem); |
| 114 | size_t newsize = cast_sizet(final_n * size_elem); |
| 115 | lua_assert(newsize <= oldsize); |
| 116 | newblock = luaM_saferealloc_(L, block, oldsize, newsize); |
| 117 | *size = final_n; |
| 118 | return newblock; |
| 119 | } |
| 120 | |
| 121 | /* }================================================================== */ |
| 122 | |
| 123 | |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 124 | l_noret luaM_toobig (lua_State *L) { |
| 125 | luaG_runerror(L, "memory allocation error: block too big"); |
| 126 | } |
| 127 | |
| 128 | |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 129 | /* |
| 130 | ** Free memory |
| 131 | */ |
| 132 | void luaM_free_ (lua_State *L, void *block, size_t osize) { |
| 133 | global_State *g = G(L); |
| 134 | lua_assert((osize == 0) == (block == NULL)); |
| 135 | (*g->frealloc)(g->ud, block, osize, 0); |
| 136 | g->GCdebt -= osize; |
| 137 | } |
| 138 | |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 139 | |
| 140 | /* |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 141 | ** In case of allocation fail, this function will call the GC to try |
| 142 | ** to free some memory and then try the allocation again. |
| 143 | ** (It should not be called when shrinking a block, because then the |
| 144 | ** interpreter may be in the middle of a collection step.) |
| 145 | */ |
| 146 | static void *tryagain (lua_State *L, void *block, |
| 147 | size_t osize, size_t nsize) { |
| 148 | global_State *g = G(L); |
| 149 | if (ttisnil(&g->nilvalue)) { /* is state fully build? */ |
| 150 | luaC_fullgc(L, 1); /* try to free some memory... */ |
| 151 | return (*g->frealloc)(g->ud, block, osize, nsize); /* try again */ |
| 152 | } |
| 153 | else return NULL; /* cannot free any memory without a full state */ |
| 154 | } |
| 155 | |
| 156 | |
| 157 | /* |
| 158 | ** Generic allocation routine. |
| 159 | ** If allocation fails while shrinking a block, do not try again; the |
| 160 | ** GC shrinks some blocks and it is not reentrant. |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 161 | */ |
| 162 | void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) { |
| 163 | void *newblock; |
| 164 | global_State *g = G(L); |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 165 | lua_assert((osize == 0) == (block == NULL)); |
| 166 | newblock = firsttry(g, block, osize, nsize); |
| 167 | if (unlikely(newblock == NULL && nsize > 0)) { |
| 168 | if (nsize > osize) /* not shrinking a block? */ |
| 169 | newblock = tryagain(L, block, osize, nsize); |
| 170 | if (newblock == NULL) /* still no memory? */ |
| 171 | return NULL; /* do not update 'GCdebt' */ |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 172 | } |
| 173 | lua_assert((nsize == 0) == (newblock == NULL)); |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 174 | g->GCdebt = (g->GCdebt + nsize) - osize; |
Lukas Zilka | 6cdd400 | 2018-12-05 23:30:46 +0100 | [diff] [blame] | 175 | return newblock; |
| 176 | } |
| 177 | |
Elliott Hughes | 3d75592 | 2020-08-05 12:30:16 -0700 | [diff] [blame] | 178 | |
| 179 | void *luaM_saferealloc_ (lua_State *L, void *block, size_t osize, |
| 180 | size_t nsize) { |
| 181 | void *newblock = luaM_realloc_(L, block, osize, nsize); |
| 182 | if (unlikely(newblock == NULL && nsize > 0)) /* allocation failed? */ |
| 183 | luaM_error(L); |
| 184 | return newblock; |
| 185 | } |
| 186 | |
| 187 | |
| 188 | void *luaM_malloc_ (lua_State *L, size_t size, int tag) { |
| 189 | if (size == 0) |
| 190 | return NULL; /* that's all */ |
| 191 | else { |
| 192 | global_State *g = G(L); |
| 193 | void *newblock = firsttry(g, NULL, tag, size); |
| 194 | if (unlikely(newblock == NULL)) { |
| 195 | newblock = tryagain(L, NULL, tag, size); |
| 196 | if (newblock == NULL) |
| 197 | luaM_error(L); |
| 198 | } |
| 199 | g->GCdebt += size; |
| 200 | return newblock; |
| 201 | } |
| 202 | } |