1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440
|
/* Copyright (C) 2001-2006 Artifex Software, Inc.
All Rights Reserved.
This software is provided AS-IS with no warranty, either express or
implied.
This software is distributed under license and may not be copied, modified
or distributed except as expressly authorized under the terms of that
license. Refer to licensing information at http://www.artifex.com/
or contact Artifex Software, Inc., 7 Mt. Lassen Drive - Suite A-134,
San Rafael, CA 94903, U.S.A., +1(415)492-9861, for further information.
*/
/* $Id: igcstr.c 9062 2008-09-03 11:42:35Z leonardo $ */
/* String GC routines for Ghostscript */
#include "memory_.h"
#include "ghost.h"
#include "gsmdebug.h"
#include "gsstruct.h"
#include "iastate.h"
#include "igcstr.h"
/* Forward references */
static bool gc_mark_string(const byte *, uint, bool, const chunk_t *);
/* (Un)mark the strings in a chunk. */
void
gc_strings_set_marks(chunk_t * cp, bool mark)
{
if (cp->smark != 0) {
if_debug3('6', "[6]clearing string marks 0x%lx[%u] to %d\n",
(ulong) cp->smark, cp->smark_size, (int)mark);
memset(cp->smark, 0, cp->smark_size);
if (mark)
gc_mark_string(cp->sbase, cp->climit - cp->sbase, true, cp);
}
}
/* We mark strings a word at a time. */
typedef string_mark_unit bword;
#define bword_log2_bytes log2_sizeof_string_mark_unit
#define bword_bytes (1 << bword_log2_bytes)
#define bword_log2_bits (bword_log2_bytes + 3)
#define bword_bits (1 << bword_log2_bits)
#define bword_1s (~(bword)0)
/* Compensate for byte order reversal if necessary. */
#if arch_is_big_endian
# if bword_bytes == 2
# define bword_swap_bytes(m) m = (m << 8) | (m >> 8)
# else /* bword_bytes == 4 */
# define bword_swap_bytes(m)\
m = (m << 24) | ((m & 0xff00) << 8) | ((m >> 8) & 0xff00) | (m >> 24)
# endif
#else
# define bword_swap_bytes(m) DO_NOTHING
#endif
/* (Un)mark a string in a known chunk. Return true iff any new marks. */
static bool
gc_mark_string(const byte * ptr, uint size, bool set, const chunk_t * cp)
{
uint offset = ptr - cp->sbase;
bword *bp = (bword *) (cp->smark + ((offset & -bword_bits) >> 3));
uint bn = offset & (bword_bits - 1);
bword m = bword_1s << bn;
uint left = size;
bword marks = 0;
bword_swap_bytes(m);
if (set) {
if (left + bn >= bword_bits) {
marks |= ~*bp & m;
*bp |= m;
m = bword_1s, left -= bword_bits - bn, bp++;
while (left >= bword_bits) {
marks |= ~*bp;
*bp = bword_1s;
left -= bword_bits, bp++;
}
}
if (left) {
bword_swap_bytes(m);
m -= m << left;
bword_swap_bytes(m);
marks |= ~*bp & m;
*bp |= m;
}
} else {
if (left + bn >= bword_bits) {
*bp &= ~m;
m = bword_1s, left -= bword_bits - bn, bp++;
if (left >= bword_bits * 5) {
memset(bp, 0, (left & -bword_bits) >> 3);
bp += left >> bword_log2_bits;
left &= bword_bits - 1;
} else
while (left >= bword_bits) {
*bp = 0;
left -= bword_bits, bp++;
}
}
if (left) {
bword_swap_bytes(m);
m -= m << left;
bword_swap_bytes(m);
*bp &= ~m;
}
}
return marks != 0;
}
#ifdef DEBUG
/* Print a string for debugging. We need this because there is no d---
* equivalent of fwrite.
*/
static void
dfwrite(const byte *ptr, uint count)
{
uint i;
for (i = 0; i < count; ++i)
dputc(ptr[i]);
}
#endif
/* Mark a string. Return true if any new marks. */
bool
gc_string_mark(const byte * ptr, uint size, bool set, gc_state_t * gcst)
{
const chunk_t *cp;
bool marks;
if (size == 0)
return false;
#define dprintstr()\
dputc('('); dfwrite(ptr, min(size, 20));\
dputs((size <= 20 ? ")" : "...)"))
if (!(cp = gc_locate(ptr, gcst))) { /* not in a chunk */
#ifdef DEBUG
if (gs_debug_c('5')) {
dlprintf2("[5]0x%lx[%u]", (ulong) ptr, size);
dprintstr();
dputs(" not in a chunk\n");
}
#endif
return false;
}
if (cp->smark == 0) /* not marking strings */
return false;
#ifdef DEBUG
if (ptr < cp->ctop) {
lprintf4("String pointer 0x%lx[%u] outside [0x%lx..0x%lx)\n",
(ulong) ptr, size, (ulong) cp->ctop, (ulong) cp->climit);
return false;
} else if (ptr + size > cp->climit) { /*
* If this is the bottommost string in a chunk that has
* an inner chunk, the string's starting address is both
* cp->ctop of the outer chunk and cp->climit of the inner;
* gc_locate may incorrectly attribute the string to the
* inner chunk because of this. This doesn't affect
* marking or relocation, since the machinery for these
* is all associated with the outermost chunk,
* but it can cause the validity check to fail.
* Check for this case now.
*/
const chunk_t *scp = cp;
while (ptr == scp->climit && scp->outer != 0)
scp = scp->outer;
if (ptr + size > scp->climit) {
lprintf4("String pointer 0x%lx[%u] outside [0x%lx..0x%lx)\n",
(ulong) ptr, size,
(ulong) scp->ctop, (ulong) scp->climit);
return false;
}
}
#endif
marks = gc_mark_string(ptr, size, set, cp);
#ifdef DEBUG
if (gs_debug_c('5')) {
dlprintf4("[5]%s%smarked 0x%lx[%u]",
(marks ? "" : "already "), (set ? "" : "un"),
(ulong) ptr, size);
dprintstr();
dputc('\n');
}
#endif
return marks;
}
/* Clear the relocation for strings. */
/* This requires setting the marks. */
void
gc_strings_clear_reloc(chunk_t * cp)
{
if (cp->sreloc != 0) {
gc_strings_set_marks(cp, true);
if_debug1('6', "[6]clearing string reloc 0x%lx\n",
(ulong) cp->sreloc);
gc_strings_set_reloc(cp);
}
}
/* Count the 0-bits in a byte. */
static const byte count_zero_bits_table[256] =
{
#define o4(n) n,n-1,n-1,n-2
#define o16(n) o4(n),o4(n-1),o4(n-1),o4(n-2)
#define o64(n) o16(n),o16(n-1),o16(n-1),o16(n-2)
o64(8), o64(7), o64(7), o64(6)
};
#define byte_count_zero_bits(byt)\
(uint)(count_zero_bits_table[byt])
#define byte_count_one_bits(byt)\
(uint)(8 - count_zero_bits_table[byt])
/* Set the relocation for the strings in a chunk. */
/* The sreloc table stores the relocated offset from climit for */
/* the beginning of each block of string_data_quantum characters. */
void
gc_strings_set_reloc(chunk_t * cp)
{
if (cp->sreloc != 0 && cp->smark != 0) {
byte *bot = cp->ctop;
byte *top = cp->climit;
uint count =
(top - bot + (string_data_quantum - 1)) >>
log2_string_data_quantum;
string_reloc_offset *relp =
cp->sreloc +
(cp->smark_size >> (log2_string_data_quantum - 3));
register const byte *bitp = cp->smark + cp->smark_size;
register string_reloc_offset reloc = 0;
/* Skip initial unrelocated strings quickly. */
#if string_data_quantum == bword_bits || string_data_quantum == bword_bits * 2
{
/* Work around the alignment aliasing bug. */
const bword *wp = (const bword *)bitp;
#if string_data_quantum == bword_bits
# define RELOC_TEST_1S(wp) (wp[-1])
#else /* string_data_quantum == bword_bits * 2 */
# define RELOC_TEST_1S(wp) (wp[-1] & wp[-2])
#endif
while (count && RELOC_TEST_1S(wp) == bword_1s) {
wp -= string_data_quantum / bword_bits;
*--relp = reloc += string_data_quantum;
--count;
}
#undef RELOC_TEST_1S
bitp = (const byte *)wp;
}
#endif
while (count--) {
bitp -= string_data_quantum / 8;
reloc += string_data_quantum -
byte_count_zero_bits(bitp[0]);
reloc -= byte_count_zero_bits(bitp[1]);
reloc -= byte_count_zero_bits(bitp[2]);
reloc -= byte_count_zero_bits(bitp[3]);
#if log2_string_data_quantum > 5
reloc -= byte_count_zero_bits(bitp[4]);
reloc -= byte_count_zero_bits(bitp[5]);
reloc -= byte_count_zero_bits(bitp[6]);
reloc -= byte_count_zero_bits(bitp[7]);
#endif
*--relp = reloc;
}
}
cp->sdest = cp->climit;
}
/* Relocate a string pointer. */
void
igc_reloc_string(gs_string * sptr, gc_state_t * gcst)
{
byte *ptr;
const chunk_t *cp;
uint offset;
uint reloc;
const byte *bitp;
byte byt;
if (sptr->size == 0) {
sptr->data = 0;
return;
}
ptr = sptr->data;
if (!(cp = gc_locate(ptr, gcst))) /* not in a chunk */
return;
if (cp->sreloc == 0 || cp->smark == 0) /* not marking strings */
return;
offset = ptr - cp->sbase;
reloc = cp->sreloc[offset >> log2_string_data_quantum];
bitp = &cp->smark[offset >> 3];
switch (offset & (string_data_quantum - 8)) {
#if log2_string_data_quantum > 5
case 56:
reloc -= byte_count_one_bits(bitp[-7]);
case 48:
reloc -= byte_count_one_bits(bitp[-6]);
case 40:
reloc -= byte_count_one_bits(bitp[-5]);
case 32:
reloc -= byte_count_one_bits(bitp[-4]);
#endif
case 24:
reloc -= byte_count_one_bits(bitp[-3]);
case 16:
reloc -= byte_count_one_bits(bitp[-2]);
case 8:
reloc -= byte_count_one_bits(bitp[-1]);
}
byt = *bitp & (0xff >> (8 - (offset & 7)));
reloc -= byte_count_one_bits(byt);
if_debug2('5', "[5]relocate string 0x%lx to 0x%lx\n",
(ulong) ptr, (ulong) (cp->sdest - reloc));
sptr->data = cp->sdest - reloc;
}
void
igc_reloc_const_string(gs_const_string * sptr, gc_state_t * gcst)
{ /* We assume the representation of byte * and const byte * is */
/* the same.... */
igc_reloc_string((gs_string *) sptr, gcst);
}
void
igc_reloc_param_string(gs_param_string * sptr, gc_state_t * gcst)
{
if (!sptr->persistent) {
/* We assume that gs_param_string is a subclass of gs_string. */
igc_reloc_string((gs_string *)sptr, gcst);
}
}
/* Compact the strings in a chunk. */
void
gc_strings_compact(chunk_t * cp)
{
if (cp->smark != 0) {
byte *hi = cp->climit;
byte *lo = cp->ctop;
const byte *from = hi;
byte *to = hi;
const byte *bp = cp->smark + cp->smark_size;
#ifdef DEBUG
if (gs_debug_c('4') || gs_debug_c('5')) {
byte *base = cp->sbase;
uint i = (lo - base) & -string_data_quantum;
uint n = ROUND_UP(hi - base, string_data_quantum);
#define R 16
for (; i < n; i += R) {
uint j;
dlprintf1("[4]0x%lx: ", (ulong) (base + i));
for (j = i; j < i + R; j++) {
byte ch = base[j];
if (ch <= 31) {
dputc('^');
dputc(ch + 0100);
} else
dputc(ch);
}
dputc(' ');
for (j = i; j < i + R; j++)
dputc((cp->smark[j >> 3] & (1 << (j & 7)) ?
'+' : '.'));
#undef R
if (!(i & (string_data_quantum - 1)))
dprintf1(" %u", cp->sreloc[i >> log2_string_data_quantum]);
dputc('\n');
}
}
#endif
/*
* Skip unmodified strings quickly. We know that cp->smark is
* aligned to a string_mark_unit.
*/
{
/* Work around the alignment aliasing bug. */
const bword *wp = (const bword *)bp;
while (to > lo && wp[-1] == bword_1s)
to -= bword_bits, --wp;
bp = (const byte *)wp;
while (to > lo && bp[-1] == 0xff)
to -= 8, --bp;
}
from = to;
while (from > lo) {
byte b = *--bp;
from -= 8;
switch (b) {
case 0xff:
to -= 8;
/*
* Since we've seen a byte other than 0xff, we know
* to != from at this point.
*/
to[7] = from[7];
to[6] = from[6];
to[5] = from[5];
to[4] = from[4];
to[3] = from[3];
to[2] = from[2];
to[1] = from[1];
to[0] = from[0];
break;
default:
if (b & 0x80)
*--to = from[7];
if (b & 0x40)
*--to = from[6];
if (b & 0x20)
*--to = from[5];
if (b & 0x10)
*--to = from[4];
if (b & 8)
*--to = from[3];
if (b & 4)
*--to = from[2];
if (b & 2)
*--to = from[1];
if (b & 1)
*--to = from[0];
/* falls through */
case 0:
;
}
}
gs_alloc_fill(cp->ctop, gs_alloc_fill_collected,
to - cp->ctop);
cp->ctop = to;
}
}
|