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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_TYPEMASK 0x001f /* mask for above immediate types */
88
89 #define JOF_NAME (1U<<5) /* name operation */
90 #define JOF_PROP (2U<<5) /* obj.prop operation */
91 #define JOF_ELEM (3U<<5) /* obj[index] operation */
92 #define JOF_XMLNAME (4U<<5) /* XML name: *, a::b, @a, @a::b, etc. */
93 #define JOF_VARPROP (5U<<5) /* x.prop for this, arg, var, or local x */
94 #define JOF_MODEMASK (7U<<5) /* mask for above addressing modes */
95 #define JOF_SET (1U<<8) /* set (i.e., assignment) operation */
96 #define JOF_DEL (1U<<9) /* delete operation */
97 #define JOF_DEC (1U<<10) /* decrement (--, not ++) opcode */
98 #define JOF_INC (2U<<10) /* increment (++, not --) opcode */
99 #define JOF_INCDEC (3U<<10) /* increment or decrement opcode */
100 #define JOF_POST (1U<<12) /* postorder increment or decrement */
101 #define JOF_FOR (1U<<13) /* for-in property op (akin to JOF_SET) */
102 #define JOF_ASSIGNING JOF_SET /* hint for JSClass.resolve, used for ops
103 that do simplex assignment */
104 #define JOF_DETECTING (1U<<14) /* object detection for JSNewResolveOp */
105 #define JOF_BACKPATCH (1U<<15) /* backpatch placeholder during codegen */
106 #define JOF_LEFTASSOC (1U<<16) /* left-associative operator */
107 #define JOF_DECLARING (1U<<17) /* var, const, or function declaration op */
108 #define JOF_INDEXBASE (1U<<18) /* atom segment base setting prefix op */
109 #define JOF_CALLOP (1U<<19) /* call operation that pushes function and
110 this */
111 #define JOF_PARENHEAD (1U<<20) /* opcode consumes value of expression in
112 parenthesized statement head */
113 #define JOF_INVOKE (1U<<21) /* JSOP_CALL, JSOP_NEW, JSOP_EVAL */
114 #define JOF_TMPSLOT (1U<<22) /* interpreter uses extra temporary slot
115 to root intermediate objects besides
116 the slots opcode uses */
117 #define JOF_TMPSLOT2 (2U<<22) /* interpreter uses extra 2 temporary slot
118 besides the slots opcode uses */
119 #define JOF_TMPSLOT_SHIFT 22
120 #define JOF_TMPSLOT_MASK (JS_BITMASK(2) << JOF_TMPSLOT_SHIFT)
121
122 /* Shorthands for type from format and type from opcode. */
123 #define JOF_TYPE(fmt) ((fmt) & JOF_TYPEMASK)
124 #define JOF_OPTYPE(op) JOF_TYPE(js_CodeSpec[op].format)
125
126 /* Shorthands for mode from format and mode from opcode. */
127 #define JOF_MODE(fmt) ((fmt) & JOF_MODEMASK)
128 #define JOF_OPMODE(op) JOF_MODE(js_CodeSpec[op].format)
129
130 #define JOF_TYPE_IS_EXTENDED_JUMP(t) \
131 ((unsigned)((t) - JOF_JUMPX) <= (unsigned)(JOF_LOOKUPSWITCHX - JOF_JUMPX))
132
133 /*
134 * Immediate operand getters, setters, and bounds.
135 */
136
137 /* Common uint16 immediate format helpers. */
138 #define UINT16_LEN 2
139 #define UINT16_HI(i) ((jsbytecode)((i) >> 8))
140 #define UINT16_LO(i) ((jsbytecode)(i))
141 #define GET_UINT16(pc) ((uintN)(((pc)[1] << 8) | (pc)[2]))
142 #define SET_UINT16(pc,i) ((pc)[1] = UINT16_HI(i), (pc)[2] = UINT16_LO(i))
143 #define UINT16_LIMIT ((uintN)1 << 16)
144
145 /* Short (2-byte signed offset) relative jump macros. */
146 #define JUMP_OFFSET_LEN 2
147 #define JUMP_OFFSET_HI(off) ((jsbytecode)((off) >> 8))
148 #define JUMP_OFFSET_LO(off) ((jsbytecode)(off))
149 #define GET_JUMP_OFFSET(pc) ((int16)GET_UINT16(pc))
150 #define SET_JUMP_OFFSET(pc,off) ((pc)[1] = JUMP_OFFSET_HI(off), \
151 (pc)[2] = JUMP_OFFSET_LO(off))
152 #define JUMP_OFFSET_MIN ((int16)0x8000)
153 #define JUMP_OFFSET_MAX ((int16)0x7fff)
154
155 /*
156 * When a short jump won't hold a relative offset, its 2-byte immediate offset
157 * operand is an unsigned index of a span-dependency record, maintained until
158 * code generation finishes -- after which some (but we hope not nearly all)
159 * span-dependent jumps must be extended (see OptimizeSpanDeps in jsemit.c).
160 *
161 * If the span-dependency record index overflows SPANDEP_INDEX_MAX, the jump
162 * offset will contain SPANDEP_INDEX_HUGE, indicating that the record must be
163 * found (via binary search) by its "before span-dependency optimization" pc
164 * offset (from script main entry point).
165 */
166 #define GET_SPANDEP_INDEX(pc) ((uint16)GET_UINT16(pc))
167 #define SET_SPANDEP_INDEX(pc,i) ((pc)[1] = JUMP_OFFSET_HI(i), \
168 (pc)[2] = JUMP_OFFSET_LO(i))
169 #define SPANDEP_INDEX_MAX ((uint16)0xfffe)
170 #define SPANDEP_INDEX_HUGE ((uint16)0xffff)
171
172 /* Ultimately, if short jumps won't do, emit long (4-byte signed) offsets. */
173 #define JUMPX_OFFSET_LEN 4
174 #define JUMPX_OFFSET_B3(off) ((jsbytecode)((off) >> 24))
175 #define JUMPX_OFFSET_B2(off) ((jsbytecode)((off) >> 16))
176 #define JUMPX_OFFSET_B1(off) ((jsbytecode)((off) >> 8))
177 #define JUMPX_OFFSET_B0(off) ((jsbytecode)(off))
178 #define GET_JUMPX_OFFSET(pc) ((int32)(((pc)[1] << 24) | ((pc)[2] << 16) \
179 | ((pc)[3] << 8) | (pc)[4]))
180 #define SET_JUMPX_OFFSET(pc,off)((pc)[1] = JUMPX_OFFSET_B3(off), \
181 (pc)[2] = JUMPX_OFFSET_B2(off), \
182 (pc)[3] = JUMPX_OFFSET_B1(off), \
183 (pc)[4] = JUMPX_OFFSET_B0(off))
184 #define JUMPX_OFFSET_MIN ((int32)0x80000000)
185 #define JUMPX_OFFSET_MAX ((int32)0x7fffffff)
186
187 /*
188 * A literal is indexed by a per-script atom or object maps. Most scripts
189 * have relatively few literals, so the standard JOF_ATOM, JOF_OBJECT and
190 * JOF_REGEXP formats specifies a fixed 16 bits of immediate operand index.
191 * A script with more than 64K literals must wrap the bytecode into
192 * JSOP_INDEXBASE and JSOP_RESETBASE pair.
193 */
194 #define INDEX_LEN 2
195 #define INDEX_HI(i) ((jsbytecode)((i) >> 8))
196 #define INDEX_LO(i) ((jsbytecode)(i))
197 #define GET_INDEX(pc) GET_UINT16(pc)
198 #define SET_INDEX(pc,i) ((pc)[1] = INDEX_HI(i), (pc)[2] = INDEX_LO(i))
199
200 #define GET_INDEXBASE(pc) (JS_ASSERT(*(pc) == JSOP_INDEXBASE), \
201 ((uintN)((pc)[1])) << 16)
202 #define INDEXBASE_LEN 1
203
204 #define UINT24_HI(i) ((jsbytecode)((i) >> 16))
205 #define UINT24_MID(i) ((jsbytecode)((i) >> 8))
206 #define UINT24_LO(i) ((jsbytecode)(i))
207 #define GET_UINT24(pc) ((jsatomid)(((pc)[1] << 16) | \
208 ((pc)[2] << 8) | \
209 (pc)[3]))
210 #define SET_UINT24(pc,i) ((pc)[1] = UINT24_HI(i), \
211 (pc)[2] = UINT24_MID(i), \
212 (pc)[3] = UINT24_LO(i))
213
214 #define GET_INT8(pc) ((jsint)(int8)(pc)[1])
215
216 #define GET_INT32(pc) ((jsint)(((uint32)((pc)[1]) << 24) | \
217 ((uint32)((pc)[2]) << 16) | \
218 ((uint32)((pc)[3]) << 8) | \
219 (uint32)(pc)[4]))
220 #define SET_INT32(pc,i) ((pc)[1] = (jsbytecode)((uint32)(i) >> 24), \
221 (pc)[2] = (jsbytecode)((uint32)(i) >> 16), \
222 (pc)[3] = (jsbytecode)((uint32)(i) >> 8), \
223 (pc)[4] = (jsbytecode)(uint32)(i))
224
225 /* Index limit is determined by SN_3BYTE_OFFSET_FLAG, see jsemit.h. */
226 #define INDEX_LIMIT_LOG2 23
227 #define INDEX_LIMIT ((uint32)1 << INDEX_LIMIT_LOG2)
228
229 /* Actual argument count operand format helpers. */
230 #define ARGC_HI(argc) UINT16_HI(argc)
231 #define ARGC_LO(argc) UINT16_LO(argc)
232 #define GET_ARGC(pc) GET_UINT16(pc)
233 #define ARGC_LIMIT UINT16_LIMIT
234
235 /* Synonyms for quick JOF_QARG and JOF_LOCAL bytecodes. */
236 #define GET_ARGNO(pc) GET_UINT16(pc)
237 #define SET_ARGNO(pc,argno) SET_UINT16(pc,argno)
238 #define ARGNO_LEN 2
239 #define ARGNO_LIMIT UINT16_LIMIT
240
241 #define GET_SLOTNO(pc) GET_UINT16(pc)
242 #define SET_SLOTNO(pc,varno) SET_UINT16(pc,varno)
243 #define SLOTNO_LEN 2
244 #define SLOTNO_LIMIT UINT16_LIMIT
245
246 struct JSCodeSpec {
247 int8 length; /* length including opcode byte */
248 int8 nuses; /* arity, -1 if variadic */
249 int8 ndefs; /* number of stack results */
250 uint8 prec; /* operator precedence */
251 uint32 format; /* immediate operand format */
252 };
253
254 extern const JSCodeSpec js_CodeSpec[];
255 extern uintN js_NumCodeSpecs;
256 extern const char *js_CodeName[];
257 extern const char js_EscapeMap[];
258
259 /*
260 * Return a GC'ed string containing the chars in str, with any non-printing
261 * chars or quotes (' or " as specified by the quote argument) escaped, and
262 * with the quote character at the beginning and end of the result string.
263 */
264 extern JSString *
265 js_QuoteString(JSContext *cx, JSString *str, jschar quote);
266
267 /*
268 * JSPrinter operations, for printf style message formatting. The return
269 * value from js_GetPrinterOutput() is the printer's cumulative output, in
270 * a GC'ed string.
271 */
272
273 #ifdef JS_ARENAMETER
274 # define JS_NEW_PRINTER(cx, name, fun, indent, pretty) \
275 js_NewPrinter(cx, name, fun, indent, pretty)
276 #else
277 # define JS_NEW_PRINTER(cx, name, fun, indent, pretty) \
278 js_NewPrinter(cx, fun, indent, pretty)
279 #endif
280
281 extern JSPrinter *
282 JS_NEW_PRINTER(JSContext *cx, const char *name, JSFunction *fun,
283 uintN indent, JSBool pretty);
284
285 extern void
286 js_DestroyPrinter(JSPrinter *jp);
287
288 extern JSString *
289 js_GetPrinterOutput(JSPrinter *jp);
290
291 extern int
292 js_printf(JSPrinter *jp, const char *format, ...);
293
294 extern JSBool
295 js_puts(JSPrinter *jp, const char *s);
296
297 /*
298 * Get index operand from the bytecode using a bytecode analysis to deduce the
299 * the index register. This function is infallible, in spite of taking cx as
300 * its first parameter; it uses only cx->runtime when calling JS_GetTrapOpcode.
301 * The GET_*_FROM_BYTECODE macros that call it pick up cx from their caller's
302 * lexical environments.
303 */
304 uintN
305 js_GetIndexFromBytecode(JSContext *cx, JSScript *script, jsbytecode *pc,
306 ptrdiff_t pcoff);
307
308 /*
309 * A slower version of GET_ATOM when the caller does not want to maintain
310 * the index segment register itself.
311 */
312 #define GET_ATOM_FROM_BYTECODE(script, pc, pcoff, atom) \
313 JS_BEGIN_MACRO \
314 uintN index_ = js_GetIndexFromBytecode(cx, (script), (pc), (pcoff)); \
315 JS_GET_SCRIPT_ATOM((script), index_, atom); \
316 JS_END_MACRO
317
318 #define GET_OBJECT_FROM_BYTECODE(script, pc, pcoff, obj) \
319 JS_BEGIN_MACRO \
320 uintN index_ = js_GetIndexFromBytecode(cx, (script), (pc), (pcoff)); \
321 JS_GET_SCRIPT_OBJECT((script), index_, obj); \
322 JS_END_MACRO
323
324 #define GET_FUNCTION_FROM_BYTECODE(script, pc, pcoff, fun) \
325 JS_BEGIN_MACRO \
326 uintN index_ = js_GetIndexFromBytecode(cx, (script), (pc), (pcoff)); \
327 JS_GET_SCRIPT_FUNCTION((script), index_, fun); \
328 JS_END_MACRO
329
330 #define GET_REGEXP_FROM_BYTECODE(script, pc, pcoff, obj) \
331 JS_BEGIN_MACRO \
332 uintN index_ = js_GetIndexFromBytecode(cx, (script), (pc), (pcoff)); \
333 JS_GET_SCRIPT_REGEXP((script), index_, obj); \
334 JS_END_MACRO
335
336 /*
337 * Get the length of variable-length bytecode like JSOP_TABLESWITCH.
338 */
339 extern uintN
340 js_GetVariableBytecodeLength(jsbytecode *pc);
341
342 /*
343 * Find the number of stack slots used by a variadic opcode such as JSOP_CALL
344 * or JSOP_NEWARRAY (for such ops, JSCodeSpec.nuses is -1).
345 */
346 extern uintN
347 js_GetVariableStackUses(JSOp op, jsbytecode *pc);
348
349 /*
350 * Find the number of stack slots defined by JSOP_ENTERBLOCK (for this op,
351 * JSCodeSpec.ndefs is -1).
352 */
353 extern uintN
354 js_GetEnterBlockStackDefs(JSContext *cx, JSScript *script, jsbytecode *pc);
355
356 #ifdef __cplusplus /* Aargh, libgjs, bug 492720. */
357 static JS_INLINE uintN
358 js_GetStackUses(const JSCodeSpec *cs, JSOp op, jsbytecode *pc)
359 {
360 JS_ASSERT(cs == &js_CodeSpec[op]);
361 if (cs->nuses >= 0)
362 return cs->nuses;
363 return js_GetVariableStackUses(op, pc);
364 }
365
366 static JS_INLINE uintN
367 js_GetStackDefs(JSContext *cx, const JSCodeSpec *cs, JSOp op, JSScript *script,
368 jsbytecode *pc)
369 {
370 JS_ASSERT(cs == &js_CodeSpec[op]);
371 if (cs->ndefs >= 0)
372 return cs->ndefs;
373
374 /* Only JSOP_ENTERBLOCK has a variable number of stack defs. */
375 JS_ASSERT(op == JSOP_ENTERBLOCK);
376 return js_GetEnterBlockStackDefs(cx, script, pc);
377 }
378 #endif
379
380 #ifdef DEBUG
381 /*
382 * Disassemblers, for debugging only.
383 */
384 #include <stdio.h>
385
386 extern JS_FRIEND_API(JSBool)
387 js_Disassemble(JSContext *cx, JSScript *script, JSBool lines, FILE *fp);
388
389 extern JS_FRIEND_API(uintN)
390 js_Disassemble1(JSContext *cx, JSScript *script, jsbytecode *pc, uintN loc,
391 JSBool lines, FILE *fp);
392 #endif /* DEBUG */
393
394 /*
395 * Decompilers, for script, function, and expression pretty-printing.
396 */
397 extern JSBool
398 js_DecompileScript(JSPrinter *jp, JSScript *script);
399
400 extern JSBool
401 js_DecompileFunctionBody(JSPrinter *jp);
402
403 extern JSBool
404 js_DecompileFunction(JSPrinter *jp);
405
406 /*
407 * Find the source expression that resulted in v, and return a newly allocated
408 * C-string containing it. Fall back on v's string conversion (fallback) if we
409 * can't find the bytecode that generated and pushed v on the operand stack.
410 *
411 * Search the current stack frame if spindex is JSDVG_SEARCH_STACK. Don't
412 * look for v on the stack if spindex is JSDVG_IGNORE_STACK. Otherwise,
413 * spindex is the negative index of v, measured from cx->fp->sp, or from a
414 * lower frame's sp if cx->fp is native.
415 *
416 * The caller must call JS_free on the result after a succsesful call.
417 */
418 extern char *
419 js_DecompileValueGenerator(JSContext *cx, intN spindex, jsval v,
420 JSString *fallback);
421
422 #define JSDVG_IGNORE_STACK 0
423 #define JSDVG_SEARCH_STACK 1
424
425 /*
426 * Given bytecode address pc in script's main program code, return the operand
427 * stack depth just before (JSOp) *pc executes.
428 */
429 extern uintN
430 js_ReconstructStackDepth(JSContext *cx, JSScript *script, jsbytecode *pc);
431
432 JS_END_EXTERN_C
433
434 #endif /* jsopcode_h___ */

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