js/src/jsopcode.h

   1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   2  *
   3  * ***** BEGIN LICENSE BLOCK *****
   4  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   5  *
   6  * The contents of this file are subject to the Mozilla Public License Version
   7  * 1.1 (the "License"); you may not use this file except in compliance with
   8  * the License. You may obtain a copy of the License at
   9  * http://www.mozilla.org/MPL/
  10  *
  11  * Software distributed under the License is distributed on an "AS IS" basis,
  12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  13  * for the specific language governing rights and limitations under the
  14  * License.
  15  *
  16  * The Original Code is Mozilla Communicator client code, released
  17  * March 31, 1998.
  18  *
  19  * The Initial Developer of the Original Code is
  20  * Netscape Communications Corporation.
  21  * Portions created by the Initial Developer are Copyright (C) 1998
  22  * the Initial Developer. All Rights Reserved.
  23  *
  24  * Contributor(s):
  25  *
  26  * Alternatively, the contents of this file may be used under the terms of
  27  * either of the GNU General Public License Version 2 or later (the "GPL"),
  28  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  29  * in which case the provisions of the GPL or the LGPL are applicable instead
  30  * of those above. If you wish to allow use of your version of this file only
  31  * under the terms of either the GPL or the LGPL, and not to allow others to
  32  * use your version of this file under the terms of the MPL, indicate your
  33  * decision by deleting the provisions above and replace them with the notice
  34  * and other provisions required by the GPL or the LGPL. If you do not delete
  35  * the provisions above, a recipient may use your version of this file under
  36  * the terms of any one of the MPL, the GPL or the LGPL.
  37  *
  38  * ***** END LICENSE BLOCK ***** */
  39
  40 #ifndef jsopcode_h___
  41 #define jsopcode_h___
  42 /*
  43  * JS bytecode definitions.
  44  */
  45 #include <stddef.h>
  46 #include "jsprvtd.h"
  47 #include "jspubtd.h"
  48 #include "jsutil.h"
  49
  50 JS_BEGIN_EXTERN_C
  51
  52 /*
  53  * JS operation bytecodes.
  54  */
  55 typedef enum JSOp {
  56 #define OPDEF(op,val,name,token,length,nuses,ndefs,prec,format) \
  57     op = val,
  58 #include "jsopcode.tbl"
  59 #undef OPDEF
  60     JSOP_LIMIT
  61 } JSOp;
  62
  63 /*
  64  * JS bytecode formats.
  65  */
  66 #define JOF_BYTE          0       /* single bytecode, no immediates */
  67 #define JOF_JUMP          1       /* signed 16-bit jump offset immediate */
  68 #define JOF_ATOM          2       /* unsigned 16-bit constant index */
  69 #define JOF_UINT16        3       /* unsigned 16-bit immediate operand */
  70 #define JOF_TABLESWITCH   4       /* table switch */
  71 #define JOF_LOOKUPSWITCH  5       /* lookup switch */
  72 #define JOF_QARG          6       /* quickened get/set function argument ops */
  73 #define JOF_LOCAL         7       /* var or block-local variable */
  74 #define JOF_SLOTATOM      8       /* uint16 slot + constant index */
  75 #define JOF_JUMPX         9       /* signed 32-bit jump offset immediate */
  76 #define JOF_TABLESWITCHX  10      /* extended (32-bit offset) table switch */
  77 #define JOF_LOOKUPSWITCHX 11      /* extended (32-bit offset) lookup switch */
  78 #define JOF_UINT24        12      /* extended unsigned 24-bit literal (index) */
  79 #define JOF_UINT8         13      /* uint8 immediate, e.g. top 8 bits of 24-bit
  80                                      atom index */
  81 #define JOF_INT32         14      /* int32 immediate operand */
  82 #define JOF_OBJECT        15      /* unsigned 16-bit object index */
  83 #define JOF_SLOTOBJECT    16      /* uint16 slot index + object index */
  84 #define JOF_REGEXP        17      /* unsigned 16-bit regexp index */
  85 #define JOF_INT8          18      /* int8 immediate operand */
  86 #define JOF_ATOMOBJECT    19      /* uint16 constant index + object index */
  87 #define JOF_UINT16PAIR    20      /* pair of uint16 immediates */
  88 #define JOF_GLOBAL        21      /* uint16 global array index */
  89 #define JOF_TYPEMASK      0x001f  /* mask for above immediate types */
  90
  91 #define JOF_NAME          (1U<<5) /* name operation */
  92 #define JOF_PROP          (2U<<5) /* obj.prop operation */
  93 #define JOF_ELEM          (3U<<5) /* obj[index] operation */
  94 #define JOF_XMLNAME       (4U<<5) /* XML name: *, a::b, @a, @a::b, etc. */
  95 #define JOF_VARPROP       (5U<<5) /* x.prop for this, arg, var, or local x */
  96 #define JOF_MODEMASK      (7U<<5) /* mask for above addressing modes */
  97 #define JOF_SET           (1U<<8) /* set (i.e., assignment) operation */
  98 #define JOF_DEL           (1U<<9) /* delete operation */
  99 #define JOF_DEC          (1U<<10) /* decrement (--, not ++) opcode */
 100 #define JOF_INC          (2U<<10) /* increment (++, not --) opcode */
 101 #define JOF_INCDEC       (3U<<10) /* increment or decrement opcode */
 102 #define JOF_POST         (1U<<12) /* postorder increment or decrement */
 103 #define JOF_FOR          (1U<<13) /* for-in property op (akin to JOF_SET) */
 104 #define JOF_ASSIGNING     JOF_SET /* hint for JSClass.resolve, used for ops
 105                                      that do simplex assignment */
 106 #define JOF_DETECTING    (1U<<14) /* object detection for JSNewResolveOp */
 107 #define JOF_BACKPATCH    (1U<<15) /* backpatch placeholder during codegen */
 108 #define JOF_LEFTASSOC    (1U<<16) /* left-associative operator */
 109 #define JOF_DECLARING    (1U<<17) /* var, const, or function declaration op */
 110 #define JOF_INDEXBASE    (1U<<18) /* atom segment base setting prefix op */
 111 #define JOF_CALLOP       (1U<<19) /* call operation that pushes function and
 112                                      this */
 113 #define JOF_PARENHEAD    (1U<<20) /* opcode consumes value of expression in
 114                                      parenthesized statement head */
 115 #define JOF_INVOKE       (1U<<21) /* JSOP_CALL, JSOP_NEW, JSOP_EVAL */
 116 #define JOF_TMPSLOT      (1U<<22) /* interpreter uses extra temporary slot
 117                                      to root intermediate objects besides
 118                                      the slots opcode uses */
 119 #define JOF_TMPSLOT2     (2U<<22) /* interpreter uses extra 2 temporary slot
 120                                      besides the slots opcode uses */
 121 #define JOF_TMPSLOT_SHIFT 22
 122 #define JOF_TMPSLOT_MASK  (JS_BITMASK(2) << JOF_TMPSLOT_SHIFT)
 123
 124 #define JOF_SHARPSLOT    (1U<<24) /* first immediate is uint16 stack slot no.
 125                                      that needs fixup when in global code (see
 126                                      Compiler::compileScript) */
 127
 128 /* Shorthands for type from format and type from opcode. */
 129 #define JOF_TYPE(fmt)   ((fmt) & JOF_TYPEMASK)
 130 #define JOF_OPTYPE(op)  JOF_TYPE(js_CodeSpec[op].format)
 131
 132 /* Shorthands for mode from format and mode from opcode. */
 133 #define JOF_MODE(fmt)   ((fmt) & JOF_MODEMASK)
 134 #define JOF_OPMODE(op)  JOF_MODE(js_CodeSpec[op].format)
 135
 136 #define JOF_TYPE_IS_EXTENDED_JUMP(t) \
 137     ((unsigned)((t) - JOF_JUMPX) <= (unsigned)(JOF_LOOKUPSWITCHX - JOF_JUMPX))
 138
 139 /*
 140  * Immediate operand getters, setters, and bounds.
 141  */
 142
 143 /* Common uint16 immediate format helpers. */
 144 #define UINT16_LEN              2
 145 #define UINT16_HI(i)            ((jsbytecode)((i) >> 8))
 146 #define UINT16_LO(i)            ((jsbytecode)(i))
 147 #define GET_UINT16(pc)          ((uintN)(((pc)[1] << 8) | (pc)[2]))
 148 #define SET_UINT16(pc,i)        ((pc)[1] = UINT16_HI(i), (pc)[2] = UINT16_LO(i))
 149 #define UINT16_LIMIT            ((uintN)1 << 16)
 150
 151 /* Short (2-byte signed offset) relative jump macros. */
 152 #define JUMP_OFFSET_LEN         2
 153 #define JUMP_OFFSET_HI(off)     ((jsbytecode)((off) >> 8))
 154 #define JUMP_OFFSET_LO(off)     ((jsbytecode)(off))
 155 #define GET_JUMP_OFFSET(pc)     ((int16)GET_UINT16(pc))
 156 #define SET_JUMP_OFFSET(pc,off) ((pc)[1] = JUMP_OFFSET_HI(off),               \
 157                                  (pc)[2] = JUMP_OFFSET_LO(off))
 158 #define JUMP_OFFSET_MIN         ((int16)0x8000)
 159 #define JUMP_OFFSET_MAX         ((int16)0x7fff)
 160
 161 /*
 162  * When a short jump won't hold a relative offset, its 2-byte immediate offset
 163  * operand is an unsigned index of a span-dependency record, maintained until
 164  * code generation finishes -- after which some (but we hope not nearly all)
 165  * span-dependent jumps must be extended (see OptimizeSpanDeps in jsemit.c).
 166  *
 167  * If the span-dependency record index overflows SPANDEP_INDEX_MAX, the jump
 168  * offset will contain SPANDEP_INDEX_HUGE, indicating that the record must be
 169  * found (via binary search) by its "before span-dependency optimization" pc
 170  * offset (from script main entry point).
 171  */
 172 #define GET_SPANDEP_INDEX(pc)   ((uint16)GET_UINT16(pc))
 173 #define SET_SPANDEP_INDEX(pc,i) ((pc)[1] = JUMP_OFFSET_HI(i),                 \
 174                                  (pc)[2] = JUMP_OFFSET_LO(i))
 175 #define SPANDEP_INDEX_MAX       ((uint16)0xfffe)
 176 #define SPANDEP_INDEX_HUGE      ((uint16)0xffff)
 177
 178 /* Ultimately, if short jumps won't do, emit long (4-byte signed) offsets. */
 179 #define JUMPX_OFFSET_LEN        4
 180 #define JUMPX_OFFSET_B3(off)    ((jsbytecode)((off) >> 24))
 181 #define JUMPX_OFFSET_B2(off)    ((jsbytecode)((off) >> 16))
 182 #define JUMPX_OFFSET_B1(off)    ((jsbytecode)((off) >> 8))
 183 #define JUMPX_OFFSET_B0(off)    ((jsbytecode)(off))
 184 #define GET_JUMPX_OFFSET(pc)    ((int32)(((pc)[1] << 24) | ((pc)[2] << 16)    \
 185                                          | ((pc)[3] << 8) | (pc)[4]))
 186 #define SET_JUMPX_OFFSET(pc,off)((pc)[1] = JUMPX_OFFSET_B3(off),              \
 187                                  (pc)[2] = JUMPX_OFFSET_B2(off),              \
 188                                  (pc)[3] = JUMPX_OFFSET_B1(off),              \
 189                                  (pc)[4] = JUMPX_OFFSET_B0(off))
 190 #define JUMPX_OFFSET_MIN        ((int32)0x80000000)
 191 #define JUMPX_OFFSET_MAX        ((int32)0x7fffffff)
 192
 193 /*
 194  * A literal is indexed by a per-script atom or object maps. Most scripts
 195  * have relatively few literals, so the standard JOF_ATOM, JOF_OBJECT and
 196  * JOF_REGEXP formats specifies a fixed 16 bits of immediate operand index.
 197  * A script with more than 64K literals must wrap the bytecode into
 198  * JSOP_INDEXBASE and JSOP_RESETBASE pair.
 199  */
 200 #define INDEX_LEN               2
 201 #define INDEX_HI(i)             ((jsbytecode)((i) >> 8))
 202 #define INDEX_LO(i)             ((jsbytecode)(i))
 203 #define GET_INDEX(pc)           GET_UINT16(pc)
 204 #define SET_INDEX(pc,i)         ((pc)[1] = INDEX_HI(i), (pc)[2] = INDEX_LO(i))
 205
 206 #define GET_INDEXBASE(pc)       (JS_ASSERT(*(pc) == JSOP_INDEXBASE),          \
 207                                  ((uintN)((pc)[1])) << 16)
 208 #define INDEXBASE_LEN           1
 209
 210 #define UINT24_HI(i)            ((jsbytecode)((i) >> 16))
 211 #define UINT24_MID(i)           ((jsbytecode)((i) >> 8))
 212 #define UINT24_LO(i)            ((jsbytecode)(i))
 213 #define GET_UINT24(pc)          ((jsatomid)(((pc)[1] << 16) |                 \
 214                                             ((pc)[2] << 8) |                  \
 215                                             (pc)[3]))
 216 #define SET_UINT24(pc,i)        ((pc)[1] = UINT24_HI(i),                      \
 217                                  (pc)[2] = UINT24_MID(i),                     \
 218                                  (pc)[3] = UINT24_LO(i))
 219
 220 #define GET_INT8(pc)            ((jsint)(int8)(pc)[1])
 221
 222 #define GET_INT32(pc)           ((jsint)(((uint32)((pc)[1]) << 24) |          \
 223                                          ((uint32)((pc)[2]) << 16) |          \
 224                                          ((uint32)((pc)[3]) << 8)  |          \
 225                                          (uint32)(pc)[4]))
 226 #define SET_INT32(pc,i)         ((pc)[1] = (jsbytecode)((uint32)(i) >> 24),   \
 227                                  (pc)[2] = (jsbytecode)((uint32)(i) >> 16),   \
 228                                  (pc)[3] = (jsbytecode)((uint32)(i) >> 8),    \
 229                                  (pc)[4] = (jsbytecode)(uint32)(i))
 230
 231 /* Index limit is determined by SN_3BYTE_OFFSET_FLAG, see jsemit.h. */
 232 #define INDEX_LIMIT_LOG2        23
 233 #define INDEX_LIMIT             ((uint32)1 << INDEX_LIMIT_LOG2)
 234
 235 /* Actual argument count operand format helpers. */
 236 #define ARGC_HI(argc)           UINT16_HI(argc)
 237 #define ARGC_LO(argc)           UINT16_LO(argc)
 238 #define GET_ARGC(pc)            GET_UINT16(pc)
 239 #define ARGC_LIMIT              UINT16_LIMIT
 240
 241 /* Synonyms for quick JOF_QARG and JOF_LOCAL bytecodes. */
 242 #define GET_ARGNO(pc)           GET_UINT16(pc)
 243 #define SET_ARGNO(pc,argno)     SET_UINT16(pc,argno)
 244 #define ARGNO_LEN               2
 245 #define ARGNO_LIMIT             UINT16_LIMIT
 246
 247 #define GET_SLOTNO(pc)          GET_UINT16(pc)
 248 #define SET_SLOTNO(pc,varno)    SET_UINT16(pc,varno)
 249 #define SLOTNO_LEN              2
 250 #define SLOTNO_LIMIT            UINT16_LIMIT
 251
 252 struct JSCodeSpec {
 253     int8                length;         /* length including opcode byte */
 254     int8                nuses;          /* arity, -1 if variadic */
 255     int8                ndefs;          /* number of stack results */
 256     uint8               prec;           /* operator precedence */
 257     uint32              format;         /* immediate operand format */
 258
 259     uint32 type() const { return JOF_TYPE(format); }
 260 };
 261
 262 extern const JSCodeSpec js_CodeSpec[];
 263 extern uintN            js_NumCodeSpecs;
 264 extern const char       *js_CodeName[];
 265 extern const char       js_EscapeMap[];
 266
 267 /* Silence unreferenced formal parameter warnings */
 268 #ifdef _MSC_VER
 269 #pragma warning(push)
 270 #pragma warning(disable:4100)
 271 #endif
 272
 273 /*
 274  * Return a GC'ed string containing the chars in str, with any non-printing
 275  * chars or quotes (' or " as specified by the quote argument) escaped, and
 276  * with the quote character at the beginning and end of the result string.
 277  */
 278 extern JSString *
 279 js_QuoteString(JSContext *cx, JSString *str, jschar quote);
 280
 281 /*
 282  * JSPrinter operations, for printf style message formatting.  The return
 283  * value from js_GetPrinterOutput() is the printer's cumulative output, in
 284  * a GC'ed string.
 285  *
 286  * strict is true if the context in which the output will appear has
 287  * already been marked as strict, thus indicating that nested
 288  * functions need not be re-marked with a strict directive.  It should
 289  * be false in the outermost printer.
 290  */
 291
 292 extern JSPrinter *
 293 js_NewPrinter(JSContext *cx, const char *name, JSFunction *fun,
 294               uintN indent, JSBool pretty, JSBool grouped, JSBool strict);
 295
 296 extern void
 297 js_DestroyPrinter(JSPrinter *jp);
 298
 299 extern JSString *
 300 js_GetPrinterOutput(JSPrinter *jp);
 301
 302 extern int
 303 js_printf(JSPrinter *jp, const char *format, ...);
 304
 305 extern JSBool
 306 js_puts(JSPrinter *jp, const char *s);
 307
 308 /*
 309  * Get index operand from the bytecode using a bytecode analysis to deduce the
 310  * the index register. This function is infallible, in spite of taking cx as
 311  * its first parameter; it uses only cx->runtime when calling JS_GetTrapOpcode.
 312  * The GET_*_FROM_BYTECODE macros that call it pick up cx from their caller's
 313  * lexical environments.
 314  */
 315 uintN
 316 js_GetIndexFromBytecode(JSContext *cx, JSScript *script, jsbytecode *pc,
 317                         ptrdiff_t pcoff);
 318
 319 /*
 320  * A slower version of GET_ATOM when the caller does not want to maintain
 321  * the index segment register itself.
 322  */
 323 #define GET_ATOM_FROM_BYTECODE(script, pc, pcoff, atom)                       \
 324     JS_BEGIN_MACRO                                                            \
 325         JS_ASSERT(*(pc) != JSOP_DOUBLE);                                      \
 326         uintN index_ = js_GetIndexFromBytecode(cx, (script), (pc), (pcoff));  \
 327         JS_GET_SCRIPT_ATOM(script, pc, index_, atom);                         \
 328     JS_END_MACRO
 329
 330 /*
 331  * Variant for getting a double atom when we might be in an imacro. Bytecodes
 332  * with literals that are only ever doubles must use this macro, and never use
 333  * GET_ATOM_FROM_BYTECODE or JS_GET_SCRIPT_ATOM.
 334  *
 335  * Unfortunately some bytecodes such as JSOP_LOOKUPSWITCH have immediates that
 336  * might be string or double atoms. Those opcodes cannot be used from imacros.
 337  * See the assertions in the JSOP_DOUBLE and JSOP_LOOKUPSWTICH* opcode cases in
 338  * jsops.cpp.
 339  */
 340 #define GET_DOUBLE_FROM_BYTECODE(script, pc, pcoff, atom)                     \
 341     JS_BEGIN_MACRO                                                            \
 342         uintN index_ = js_GetIndexFromBytecode(cx, (script), (pc), (pcoff));  \
 343         JS_ASSERT(index_ < (script)->atomMap.length);                         \
 344         (atom) = (script)->atomMap.vector[index_];                            \
 345         JS_ASSERT(ATOM_IS_DOUBLE(atom));                                      \
 346     JS_END_MACRO
 347
 348 #define GET_OBJECT_FROM_BYTECODE(script, pc, pcoff, obj)                      \
 349     JS_BEGIN_MACRO                                                            \
 350         uintN index_ = js_GetIndexFromBytecode(cx, (script), (pc), (pcoff));  \
 351         obj = (script)->getObject(index_);                                    \
 352     JS_END_MACRO
 353
 354 #define GET_FUNCTION_FROM_BYTECODE(script, pc, pcoff, fun)                    \
 355     JS_BEGIN_MACRO                                                            \
 356         uintN index_ = js_GetIndexFromBytecode(cx, (script), (pc), (pcoff));  \
 357         fun = (script)->getFunction(index_);                                  \
 358     JS_END_MACRO
 359
 360 #define GET_REGEXP_FROM_BYTECODE(script, pc, pcoff, obj)                      \
 361     JS_BEGIN_MACRO                                                            \
 362         uintN index_ = js_GetIndexFromBytecode(cx, (script), (pc), (pcoff));  \
 363         obj = (script)->getRegExp(index_);                                    \
 364     JS_END_MACRO
 365
 366 /*
 367  * Get the length of variable-length bytecode like JSOP_TABLESWITCH.
 368  */
 369 extern uintN
 370 js_GetVariableBytecodeLength(jsbytecode *pc);
 371
 372 /*
 373  * Find the number of stack slots used by a variadic opcode such as JSOP_CALL
 374  * or JSOP_NEWARRAY (for such ops, JSCodeSpec.nuses is -1).
 375  */
 376 extern uintN
 377 js_GetVariableStackUses(JSOp op, jsbytecode *pc);
 378
 379 /*
 380  * Find the number of stack slots defined by JSOP_ENTERBLOCK (for this op,
 381  * JSCodeSpec.ndefs is -1).
 382  */
 383 extern uintN
 384 js_GetEnterBlockStackDefs(JSContext *cx, JSScript *script, jsbytecode *pc);
 385
 386 #ifdef __cplusplus /* Aargh, libgjs, bug 492720. */
 387 static JS_INLINE uintN
 388 js_GetStackUses(const JSCodeSpec *cs, JSOp op, jsbytecode *pc)
 389 {
 390     JS_ASSERT(cs == &js_CodeSpec[op]);
 391     if (cs->nuses >= 0)
 392         return cs->nuses;
 393     return js_GetVariableStackUses(op, pc);
 394 }
 395
 396 static JS_INLINE uintN
 397 js_GetStackDefs(JSContext *cx, const JSCodeSpec *cs, JSOp op, JSScript *script,
 398                 jsbytecode *pc)
 399 {
 400     JS_ASSERT(cs == &js_CodeSpec[op]);
 401     if (cs->ndefs >= 0)
 402         return cs->ndefs;
 403
 404     /* Only JSOP_ENTERBLOCK has a variable number of stack defs. */
 405     JS_ASSERT(op == JSOP_ENTERBLOCK);
 406     return js_GetEnterBlockStackDefs(cx, script, pc);
 407 }
 408 #endif
 409
 410 #ifdef DEBUG
 411 /*
 412  * Disassemblers, for debugging only.
 413  */
 414 #include <stdio.h>
 415
 416 extern JS_FRIEND_API(JSBool)
 417 js_Disassemble(JSContext *cx, JSScript *script, JSBool lines, FILE *fp);
 418
 419 extern JS_FRIEND_API(uintN)
 420 js_Disassemble1(JSContext *cx, JSScript *script, jsbytecode *pc, uintN loc,
 421                 JSBool lines, FILE *fp);
 422 #endif /* DEBUG */
 423
 424 /*
 425  * Decompilers, for script, function, and expression pretty-printing.
 426  */
 427 extern JSBool
 428 js_DecompileScript(JSPrinter *jp, JSScript *script);
 429
 430 extern JSBool
 431 js_DecompileFunctionBody(JSPrinter *jp);
 432
 433 extern JSBool
 434 js_DecompileFunction(JSPrinter *jp);
 435
 436 /*
 437  * Some C++ compilers treat the language linkage (extern "C" vs.
 438  * extern "C++") as part of function (and thus pointer-to-function)
 439  * types. The use of this typedef (defined in "C") ensures that
 440  * js_DecompileToString's definition (in "C++") gets matched up with
 441  * this declaration.
 442  */
 443 typedef JSBool (* JSDecompilerPtr)(JSPrinter *);
 444
 445 extern JSString *
 446 js_DecompileToString(JSContext *cx, const char *name, JSFunction *fun,
 447                      uintN indent, JSBool pretty, JSBool grouped, JSBool strict,
 448                      JSDecompilerPtr decompiler);
 449
 450 /*
 451  * Find the source expression that resulted in v, and return a newly allocated
 452  * C-string containing it.  Fall back on v's string conversion (fallback) if we
 453  * can't find the bytecode that generated and pushed v on the operand stack.
 454  *
 455  * Search the current stack frame if spindex is JSDVG_SEARCH_STACK.  Don't
 456  * look for v on the stack if spindex is JSDVG_IGNORE_STACK.  Otherwise,
 457  * spindex is the negative index of v, measured from cx->fp->sp, or from a
 458  * lower frame's sp if cx->fp is native.
 459  *
 460  * The caller must call JS_free on the result after a succsesful call.
 461  */
 462 extern char *
 463 js_DecompileValueGenerator(JSContext *cx, intN spindex, jsval v,
 464                            JSString *fallback);
 465
 466 #define JSDVG_IGNORE_STACK      0
 467 #define JSDVG_SEARCH_STACK      1
 468
 469 /*
 470  * Given bytecode address pc in script's main program code, return the operand
 471  * stack depth just before (JSOp) *pc executes.
 472  */
 473 extern uintN
 474 js_ReconstructStackDepth(JSContext *cx, JSScript *script, jsbytecode *pc);
 475
 476 #ifdef _MSC_VER
 477 #pragma warning(pop)
 478 #endif
 479
 480 JS_END_EXTERN_C
 481
 482 #endif /* jsopcode_h___ */