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 ***** */
40 #ifndef jsemit_h___
41 #define jsemit_h___
42 /*
43 * JS bytecode generation.
44 */
46 #include "jsstddef.h"
47 #include "jstypes.h"
48 #include "jsatom.h"
49 #include "jsopcode.h"
50 #include "jsprvtd.h"
51 #include "jspubtd.h"
53 JS_BEGIN_EXTERN_C
55 /*
56 * NB: If you add non-loop STMT_* enumerators, do so before STMT_DO_LOOP or
57 * you will break the STMT_IS_LOOP macro, just below this enum.
58 */
59 typedef enum JSStmtType {
60 STMT_BLOCK = 0, /* compound statement: { s1[;... sN] } */
61 STMT_LABEL = 1, /* labeled statement: L: s */
62 STMT_IF = 2, /* if (then) statement */
63 STMT_ELSE = 3, /* else clause of if statement */
64 STMT_SWITCH = 4, /* switch statement */
65 STMT_WITH = 5, /* with statement */
66 STMT_TRY = 6, /* try statement */
67 STMT_CATCH = 7, /* catch block */
68 STMT_FINALLY = 8, /* finally statement */
69 STMT_SUBROUTINE = 9, /* gosub-target subroutine body */
70 STMT_DO_LOOP = 10, /* do/while loop statement */
71 STMT_FOR_LOOP = 11, /* for loop statement */
72 STMT_FOR_IN_LOOP = 12, /* for/in loop statement */
73 STMT_WHILE_LOOP = 13 /* while loop statement */
74 } JSStmtType;
76 #define STMT_IS_LOOP(stmt) ((stmt)->type >= STMT_DO_LOOP)
78 typedef struct JSStmtInfo JSStmtInfo;
80 struct JSStmtInfo {
81 JSStmtType type; /* statement type */
82 ptrdiff_t update; /* loop update offset (top if none) */
83 ptrdiff_t breaks; /* offset of last break in loop */
84 ptrdiff_t continues; /* offset of last continue in loop */
85 ptrdiff_t gosub; /* offset of last GOSUB for this finally */
86 ptrdiff_t catchJump; /* offset of last end-of-catch jump */
87 JSAtom *label; /* name of LABEL or CATCH var */
88 JSStmtInfo *down; /* info for enclosing statement */
89 };
91 #define SET_STATEMENT_TOP(stmt, top) \
92 ((stmt)->update = (top), (stmt)->breaks = \
93 (stmt)->continues = (stmt)->catchJump = (stmt)->gosub = (-1))
95 struct JSTreeContext { /* tree context for semantic checks */
96 uint16 flags; /* statement state flags, see below */
97 uint16 numGlobalVars; /* max. no. of global variables/regexps */
98 uint32 tryCount; /* total count of try statements parsed */
99 uint32 globalUses; /* optimizable global var uses in total */
100 uint32 loopyGlobalUses;/* optimizable global var uses in loops */
101 JSStmtInfo *topStmt; /* top of statement info stack */
102 JSAtomList decls; /* function, const, and var declarations */
103 JSParseNode *nodeList; /* list of recyclable parse-node structs */
104 };
106 #define TCF_COMPILING 0x01 /* generating bytecode; this tc is a cg */
107 #define TCF_IN_FUNCTION 0x02 /* parsing inside function body */
108 #define TCF_RETURN_EXPR 0x04 /* function has 'return expr;' */
109 #define TCF_RETURN_VOID 0x08 /* function has 'return;' */
110 #define TCF_IN_FOR_INIT 0x10 /* parsing init expr of for; exclude 'in' */
111 #define TCF_FUN_CLOSURE_VS_VAR 0x20 /* function and var with same name */
112 #define TCF_FUN_USES_NONLOCALS 0x40 /* function refers to non-local names */
113 #define TCF_FUN_HEAVYWEIGHT 0x80 /* function needs Call object per call */
114 #define TCF_FUN_FLAGS 0xE0 /* flags to propagate from FunctionBody */
116 #define TREE_CONTEXT_INIT(tc) \
117 ((tc)->flags = (tc)->numGlobalVars = 0, \
118 (tc)->tryCount = (tc)->globalUses = (tc)->loopyGlobalUses = 0, \
119 (tc)->topStmt = NULL, ATOM_LIST_INIT(&(tc)->decls), \
120 (tc)->nodeList = NULL)
122 #define TREE_CONTEXT_FINISH(tc) \
123 ((void)0)
125 /*
126 * Span-dependent instructions are jumps whose span (from the jump bytecode to
127 * the jump target) may require 2 or 4 bytes of immediate operand.
128 */
129 typedef struct JSSpanDep JSSpanDep;
130 typedef struct JSJumpTarget JSJumpTarget;
132 struct JSSpanDep {
133 ptrdiff_t top; /* offset of first bytecode in an opcode */
134 ptrdiff_t offset; /* offset - 1 within opcode of jump operand */
135 ptrdiff_t before; /* original offset - 1 of jump operand */
136 JSJumpTarget *target; /* tagged target pointer or backpatch delta */
137 };
139 /*
140 * Jump targets are stored in an AVL tree, for O(log(n)) lookup with targets
141 * sorted by offset from left to right, so that targets after a span-dependent
142 * instruction whose jump offset operand must be extended can be found quickly
143 * and adjusted upward (toward higher offsets).
144 */
145 struct JSJumpTarget {
146 ptrdiff_t offset; /* offset of span-dependent jump target */
147 int balance; /* AVL tree balance number */
148 JSJumpTarget *kids[2]; /* left and right AVL tree child pointers */
149 };
151 #define JT_LEFT 0
152 #define JT_RIGHT 1
153 #define JT_OTHER_DIR(dir) (1 - (dir))
154 #define JT_IMBALANCE(dir) (((dir) << 1) - 1)
155 #define JT_DIR(imbalance) (((imbalance) + 1) >> 1)
157 /*
158 * Backpatch deltas are encoded in JSSpanDep.target if JT_TAG_BIT is clear,
159 * so we can maintain backpatch chains when using span dependency records to
160 * hold jump offsets that overflow 16 bits.
161 */
162 #define JT_TAG_BIT ((jsword) 1)
163 #define JT_UNTAG_SHIFT 1
164 #define JT_SET_TAG(jt) ((JSJumpTarget *)((jsword)(jt) | JT_TAG_BIT))
165 #define JT_CLR_TAG(jt) ((JSJumpTarget *)((jsword)(jt) & ~JT_TAG_BIT))
166 #define JT_HAS_TAG(jt) ((jsword)(jt) & JT_TAG_BIT)
168 #define BITS_PER_PTRDIFF (sizeof(ptrdiff_t) * JS_BITS_PER_BYTE)
169 #define BITS_PER_BPDELTA (BITS_PER_PTRDIFF - 1 - JT_UNTAG_SHIFT)
170 #define BPDELTA_MAX (((ptrdiff_t)1 << BITS_PER_BPDELTA) - 1)
171 #define BPDELTA_TO_JT(bp) ((JSJumpTarget *)((bp) << JT_UNTAG_SHIFT))
172 #define JT_TO_BPDELTA(jt) ((ptrdiff_t)((jsword)(jt) >> JT_UNTAG_SHIFT))
174 #define SD_SET_TARGET(sd,jt) ((sd)->target = JT_SET_TAG(jt))
175 #define SD_SET_BPDELTA(sd,bp) ((sd)->target = BPDELTA_TO_JT(bp))
176 #define SD_GET_BPDELTA(sd) (JS_ASSERT(!JT_HAS_TAG((sd)->target)), \
177 JT_TO_BPDELTA((sd)->target))
178 #define SD_TARGET_OFFSET(sd) (JS_ASSERT(JT_HAS_TAG((sd)->target)), \
179 JT_CLR_TAG((sd)->target)->offset)
181 struct JSCodeGenerator {
182 JSTreeContext treeContext; /* base state: statement info stack, etc. */
183 JSArenaPool *codePool; /* pointer to thread code arena pool */
184 JSArenaPool *notePool; /* pointer to thread srcnote arena pool */
185 void *codeMark; /* low watermark in cg->codePool */
186 void *noteMark; /* low watermark in cg->notePool */
187 void *tempMark; /* low watermark in cx->tempPool */
188 struct {
189 jsbytecode *base; /* base of JS bytecode vector */
190 jsbytecode *limit; /* one byte beyond end of bytecode */
191 jsbytecode *next; /* pointer to next free bytecode */
192 jssrcnote *notes; /* source notes, see below */
193 uintN noteCount; /* number of source notes so far */
194 uintN noteMask; /* growth increment for notes */
195 ptrdiff_t lastNoteOffset; /* code offset for last source note */
196 uintN currentLine; /* line number for tree-based srcnote gen */
197 } prolog, main, *current;
198 const char *filename; /* null or weak link to source filename */
199 uintN firstLine; /* first line, for js_NewScriptFromCG */
200 JSPrincipals *principals; /* principals for constant folding eval */
201 JSAtomList atomList; /* literals indexed for mapping */
202 intN stackDepth; /* current stack depth in script frame */
203 uintN maxStackDepth; /* maximum stack depth so far */
204 JSTryNote *tryBase; /* first exception handling note */
205 JSTryNote *tryNext; /* next available note */
206 size_t tryNoteSpace; /* # of bytes allocated at tryBase */
207 JSSpanDep *spanDeps; /* span dependent instruction records */
208 JSJumpTarget *jumpTargets; /* AVL tree of jump target offsets */
209 JSJumpTarget *jtFreeList; /* JT_LEFT-linked list of free structs */
210 uintN numSpanDeps; /* number of span dependencies */
211 uintN numJumpTargets; /* number of jump targets */
212 uintN emitLevel; /* js_EmitTree recursion level */
213 JSAtomList constList; /* compile time constants */
214 JSCodeGenerator *parent; /* Enclosing function or global context */
215 };
217 #define CG_BASE(cg) ((cg)->current->base)
218 #define CG_LIMIT(cg) ((cg)->current->limit)
219 #define CG_NEXT(cg) ((cg)->current->next)
220 #define CG_CODE(cg,offset) (CG_BASE(cg) + (offset))
221 #define CG_OFFSET(cg) PTRDIFF(CG_NEXT(cg), CG_BASE(cg), jsbytecode)
223 #define CG_NOTES(cg) ((cg)->current->notes)
224 #define CG_NOTE_COUNT(cg) ((cg)->current->noteCount)
225 #define CG_NOTE_MASK(cg) ((cg)->current->noteMask)
226 #define CG_LAST_NOTE_OFFSET(cg) ((cg)->current->lastNoteOffset)
227 #define CG_CURRENT_LINE(cg) ((cg)->current->currentLine)
229 #define CG_PROLOG_BASE(cg) ((cg)->prolog.base)
230 #define CG_PROLOG_LIMIT(cg) ((cg)->prolog.limit)
231 #define CG_PROLOG_NEXT(cg) ((cg)->prolog.next)
232 #define CG_PROLOG_CODE(cg,poff) (CG_PROLOG_BASE(cg) + (poff))
233 #define CG_PROLOG_OFFSET(cg) PTRDIFF(CG_PROLOG_NEXT(cg), CG_PROLOG_BASE(cg),\
234 jsbytecode)
236 #define CG_SWITCH_TO_MAIN(cg) ((cg)->current = &(cg)->main)
237 #define CG_SWITCH_TO_PROLOG(cg) ((cg)->current = &(cg)->prolog)
239 /*
240 * Initialize cg to allocate bytecode space from codePool, source note space
241 * from notePool, and all other arena-allocated temporaries from cx->tempPool.
242 * Return true on success. Report an error and return false if the initial
243 * code segment can't be allocated.
244 */
245 extern JS_FRIEND_API(JSBool)
246 js_InitCodeGenerator(JSContext *cx, JSCodeGenerator *cg,
247 JSArenaPool *codePool, JSArenaPool *notePool,
248 const char *filename, uintN lineno,
249 JSPrincipals *principals);
251 /*
252 * Release cg->codePool, cg->notePool, and cx->tempPool to marks set by
253 * js_InitCodeGenerator. Note that cgs are magic: they own the arena pool
254 * "tops-of-stack" space above their codeMark, noteMark, and tempMark points.
255 * This means you cannot alloc from tempPool and save the pointer beyond the
256 * next JS_FinishCodeGenerator.
257 */
258 extern JS_FRIEND_API(void)
259 js_FinishCodeGenerator(JSContext *cx, JSCodeGenerator *cg);
261 /*
262 * Emit one bytecode.
263 */
264 extern ptrdiff_t
265 js_Emit1(JSContext *cx, JSCodeGenerator *cg, JSOp op);
267 /*
268 * Emit two bytecodes, an opcode (op) with a byte of immediate operand (op1).
269 */
270 extern ptrdiff_t
271 js_Emit2(JSContext *cx, JSCodeGenerator *cg, JSOp op, jsbytecode op1);
273 /*
274 * Emit three bytecodes, an opcode with two bytes of immediate operands.
275 */
276 extern ptrdiff_t
277 js_Emit3(JSContext *cx, JSCodeGenerator *cg, JSOp op, jsbytecode op1,
278 jsbytecode op2);
280 /*
281 * Emit (1 + extra) bytecodes, for N bytes of op and its immediate operand.
282 */
283 extern ptrdiff_t
284 js_EmitN(JSContext *cx, JSCodeGenerator *cg, JSOp op, size_t extra);
286 /*
287 * Unsafe macro to call js_SetJumpOffset and return false if it does.
288 */
289 #define CHECK_AND_SET_JUMP_OFFSET(cx,cg,pc,off) \
290 JS_BEGIN_MACRO \
291 if (!js_SetJumpOffset(cx, cg, pc, off)) \
292 return JS_FALSE; \
293 JS_END_MACRO
295 #define CHECK_AND_SET_JUMP_OFFSET_AT(cx,cg,off) \
296 CHECK_AND_SET_JUMP_OFFSET(cx, cg, CG_CODE(cg,off), CG_OFFSET(cg) - (off))
298 extern JSBool
299 js_SetJumpOffset(JSContext *cx, JSCodeGenerator *cg, jsbytecode *pc,
300 ptrdiff_t off);
302 /* Test whether we're in a with statement. */
303 extern JSBool
304 js_InWithStatement(JSTreeContext *tc);
306 /* Test whether we're in a catch block with exception named by atom. */
307 extern JSBool
308 js_InCatchBlock(JSTreeContext *tc, JSAtom *atom);
310 /*
311 * Push the C-stack-allocated struct at stmt onto the stmtInfo stack.
312 */
313 extern void
314 js_PushStatement(JSTreeContext *tc, JSStmtInfo *stmt, JSStmtType type,
315 ptrdiff_t top);
317 /*
318 * Pop tc->topStmt. If the top JSStmtInfo struct is not stack-allocated, it
319 * is up to the caller to free it.
320 */
321 extern void
322 js_PopStatement(JSTreeContext *tc);
324 /*
325 * Like js_PopStatement(&cg->treeContext), also patch breaks and continues.
326 * May fail if a jump offset overflows.
327 */
328 extern JSBool
329 js_PopStatementCG(JSContext *cx, JSCodeGenerator *cg);
331 /*
332 * Define and lookup a primitive jsval associated with the const named by atom.
333 * js_DefineCompileTimeConstant analyzes the constant-folded initializer at pn
334 * and saves the const's value in cg->constList, if it can be used at compile
335 * time. It returns true unless an error occurred.
336 *
337 * If the initializer's value could not be saved, js_LookupCompileTimeConstant
338 * calls will return the undefined value. js_LookupCompileTimeConstant tries
339 * to find a const value memorized for atom, returning true with *vp set to a
340 * value other than undefined if the constant was found, true with *vp set to
341 * JSVAL_VOID if not found, and false on error.
342 */
343 extern JSBool
344 js_DefineCompileTimeConstant(JSContext *cx, JSCodeGenerator *cg, JSAtom *atom,
345 JSParseNode *pn);
347 extern JSBool
348 js_LookupCompileTimeConstant(JSContext *cx, JSCodeGenerator *cg, JSAtom *atom,
349 jsval *vp);
351 /*
352 * Emit code into cg for the tree rooted at pn.
353 */
354 extern JSBool
355 js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn);
357 /*
358 * Emit code into cg for the tree rooted at body, then create a persistent
359 * script for fun from cg.
360 */
361 extern JSBool
362 js_EmitFunctionBody(JSContext *cx, JSCodeGenerator *cg, JSParseNode *body,
363 JSFunction *fun);
365 /*
366 * Source notes generated along with bytecode for decompiling and debugging.
367 * A source note is a uint8 with 5 bits of type and 3 of offset from the pc of
368 * the previous note. If 3 bits of offset aren't enough, extended delta notes
369 * (SRC_XDELTA) consisting of 2 set high order bits followed by 6 offset bits
370 * are emitted before the next note. Some notes have operand offsets encoded
371 * immediately after them, in note bytes or byte-triples.
372 *
373 * Source Note Extended Delta
374 * +7-6-5-4-3+2-1-0+ +7-6-5+4-3-2-1-0+
375 * |note-type|delta| |1 1| ext-delta |
376 * +---------+-----+ +---+-----------+
377 *
378 * At most one "gettable" note (i.e., a note of type other than SRC_NEWLINE,
379 * SRC_SETLINE, and SRC_XDELTA) applies to a given bytecode.
380 *
381 * NB: the js_SrcNoteSpec array in jsemit.c is indexed by this enum, so its
382 * initializers need to match the order here.
383 */
384 typedef enum JSSrcNoteType {
385 SRC_NULL = 0, /* terminates a note vector */
386 SRC_IF = 1, /* JSOP_IFEQ bytecode is from an if-then */
387 SRC_IF_ELSE = 2, /* JSOP_IFEQ bytecode is from an if-then-else */
388 SRC_WHILE = 3, /* JSOP_IFEQ is from a while loop */
389 SRC_FOR = 4, /* JSOP_NOP or JSOP_POP in for loop head */
390 SRC_CONTINUE = 5, /* JSOP_GOTO is a continue, not a break;
391 also used on JSOP_ENDINIT if extra comma
392 at end of array literal: [1,2,,] */
393 SRC_VAR = 6, /* JSOP_NAME/SETNAME/FORNAME in a var decl */
394 SRC_PCDELTA = 7, /* offset from comma-operator to next POP,
395 or from CONDSWITCH to first CASE opcode */
396 SRC_ASSIGNOP = 8, /* += or another assign-op follows */
397 SRC_COND = 9, /* JSOP_IFEQ is from conditional ?: operator */
398 SRC_RESERVED0 = 10, /* reserved for future use */
399 SRC_HIDDEN = 11, /* opcode shouldn't be decompiled */
400 SRC_PCBASE = 12, /* offset of first obj.prop.subprop bytecode */
401 SRC_LABEL = 13, /* JSOP_NOP for label: with atomid immediate */
402 SRC_LABELBRACE = 14, /* JSOP_NOP for label: {...} begin brace */
403 SRC_ENDBRACE = 15, /* JSOP_NOP for label: {...} end brace */
404 SRC_BREAK2LABEL = 16, /* JSOP_GOTO for 'break label' with atomid */
405 SRC_CONT2LABEL = 17, /* JSOP_GOTO for 'continue label' with atomid */
406 SRC_SWITCH = 18, /* JSOP_*SWITCH with offset to end of switch,
407 2nd off to first JSOP_CASE if condswitch */
408 SRC_FUNCDEF = 19, /* JSOP_NOP for function f() with atomid */
409 SRC_CATCH = 20, /* catch block has guard */
410 SRC_CONST = 21, /* JSOP_SETCONST in a const decl */
411 SRC_NEWLINE = 22, /* bytecode follows a source newline */
412 SRC_SETLINE = 23, /* a file-absolute source line number note */
413 SRC_XDELTA = 24 /* 24-31 are for extended delta notes */
414 } JSSrcNoteType;
416 #define SN_TYPE_BITS 5
417 #define SN_DELTA_BITS 3
418 #define SN_XDELTA_BITS 6
419 #define SN_TYPE_MASK (JS_BITMASK(SN_TYPE_BITS) << SN_DELTA_BITS)
420 #define SN_DELTA_MASK ((ptrdiff_t)JS_BITMASK(SN_DELTA_BITS))
421 #define SN_XDELTA_MASK ((ptrdiff_t)JS_BITMASK(SN_XDELTA_BITS))
423 #define SN_MAKE_NOTE(sn,t,d) (*(sn) = (jssrcnote) \
424 (((t) << SN_DELTA_BITS) \
425 | ((d) & SN_DELTA_MASK)))
426 #define SN_MAKE_XDELTA(sn,d) (*(sn) = (jssrcnote) \
427 ((SRC_XDELTA << SN_DELTA_BITS) \
428 | ((d) & SN_XDELTA_MASK)))
430 #define SN_IS_XDELTA(sn) ((*(sn) >> SN_DELTA_BITS) >= SRC_XDELTA)
431 #define SN_TYPE(sn) (SN_IS_XDELTA(sn) ? SRC_XDELTA \
432 : *(sn) >> SN_DELTA_BITS)
433 #define SN_SET_TYPE(sn,type) SN_MAKE_NOTE(sn, type, SN_DELTA(sn))
434 #define SN_IS_GETTABLE(sn) (SN_TYPE(sn) < SRC_NEWLINE)
436 #define SN_DELTA(sn) ((ptrdiff_t)(SN_IS_XDELTA(sn) \
437 ? *(sn) & SN_XDELTA_MASK \
438 : *(sn) & SN_DELTA_MASK))
439 #define SN_SET_DELTA(sn,delta) (SN_IS_XDELTA(sn) \
440 ? SN_MAKE_XDELTA(sn, delta) \
441 : SN_MAKE_NOTE(sn, SN_TYPE(sn), delta))
443 #define SN_DELTA_LIMIT ((ptrdiff_t)JS_BIT(SN_DELTA_BITS))
444 #define SN_XDELTA_LIMIT ((ptrdiff_t)JS_BIT(SN_XDELTA_BITS))
446 /*
447 * Offset fields follow certain notes and are frequency-encoded: an offset in
448 * [0,0x7f] consumes one byte, an offset in [0x80,0x7fffff] takes three, and
449 * the high bit of the first byte is set.
450 */
451 #define SN_3BYTE_OFFSET_FLAG 0x80
452 #define SN_3BYTE_OFFSET_MASK 0x7f
454 typedef struct JSSrcNoteSpec {
455 const char *name; /* name for disassembly/debugging output */
456 uint8 arity; /* number of offset operands */
457 uint8 offsetBias; /* bias of offset(s) from annotated pc */
458 int8 isSpanDep; /* 1 or -1 if offsets could span extended ops,
459 0 otherwise; sign tells span direction */
460 } JSSrcNoteSpec;
462 extern JS_FRIEND_DATA(JSSrcNoteSpec) js_SrcNoteSpec[];
463 extern JS_FRIEND_API(uintN) js_SrcNoteLength(jssrcnote *sn);
465 #define SN_LENGTH(sn) ((js_SrcNoteSpec[SN_TYPE(sn)].arity == 0) ? 1 \
466 : js_SrcNoteLength(sn))
467 #define SN_NEXT(sn) ((sn) + SN_LENGTH(sn))
469 /* A source note array is terminated by an all-zero element. */
470 #define SN_MAKE_TERMINATOR(sn) (*(sn) = SRC_NULL)
471 #define SN_IS_TERMINATOR(sn) (*(sn) == SRC_NULL)
473 /*
474 * Append a new source note of the given type (and therefore size) to cg's
475 * notes dynamic array, updating cg->noteCount. Return the new note's index
476 * within the array pointed at by cg->current->notes. Return -1 if out of
477 * memory.
478 */
479 extern intN
480 js_NewSrcNote(JSContext *cx, JSCodeGenerator *cg, JSSrcNoteType type);
482 extern intN
483 js_NewSrcNote2(JSContext *cx, JSCodeGenerator *cg, JSSrcNoteType type,
484 ptrdiff_t offset);
486 extern intN
487 js_NewSrcNote3(JSContext *cx, JSCodeGenerator *cg, JSSrcNoteType type,
488 ptrdiff_t offset1, ptrdiff_t offset2);
490 /*
491 * NB: this function can add at most one extra extended delta note.
492 */
493 extern jssrcnote *
494 js_AddToSrcNoteDelta(JSContext *cx, JSCodeGenerator *cg, jssrcnote *sn,
495 ptrdiff_t delta);
497 /*
498 * Get and set the offset operand identified by which (0 for the first, etc.).
499 */
500 extern JS_FRIEND_API(ptrdiff_t)
501 js_GetSrcNoteOffset(jssrcnote *sn, uintN which);
503 extern JSBool
504 js_SetSrcNoteOffset(JSContext *cx, JSCodeGenerator *cg, uintN index,
505 uintN which, ptrdiff_t offset);
507 /*
508 * Finish taking source notes in cx's notePool, copying final notes to the new
509 * stable store allocated by the caller and passed in via notes. Return false
510 * on malloc failure, which means this function reported an error.
511 *
512 * To compute the number of jssrcnotes to allocate and pass in via notes, use
513 * the CG_COUNT_FINAL_SRCNOTES macro. This macro knows a lot about details of
514 * js_FinishTakingSrcNotes, SO DON'T CHANGE jsemit.c's js_FinishTakingSrcNotes
515 * FUNCTION WITHOUT CHECKING WHETHER THIS MACRO NEEDS CORRESPONDING CHANGES!
516 */
517 #define CG_COUNT_FINAL_SRCNOTES(cg, cnt) \
518 JS_BEGIN_MACRO \
519 ptrdiff_t diff_ = CG_PROLOG_OFFSET(cg) - (cg)->prolog.lastNoteOffset; \
520 cnt = (cg)->prolog.noteCount + (cg)->main.noteCount + 1; \
521 if ((cg)->prolog.noteCount && \
522 (cg)->prolog.currentLine != (cg)->firstLine) { \
523 if (diff_ > SN_DELTA_MASK) \
524 cnt += JS_HOWMANY(diff_ - SN_DELTA_MASK, SN_XDELTA_MASK); \
525 cnt += 2 + (((cg)->firstLine > SN_3BYTE_OFFSET_MASK) << 1); \
526 } else if (diff_ > 0) { \
527 if (cg->main.noteCount) { \
528 jssrcnote *sn_ = (cg)->main.notes; \
529 diff_ -= SN_IS_XDELTA(sn_) \
530 ? SN_XDELTA_MASK - (*sn_ & SN_XDELTA_MASK) \
531 : SN_DELTA_MASK - (*sn_ & SN_DELTA_MASK); \
532 } \
533 if (diff_ > 0) \
534 cnt += JS_HOWMANY(diff_, SN_XDELTA_MASK); \
535 } \
536 JS_END_MACRO
538 extern JSBool
539 js_FinishTakingSrcNotes(JSContext *cx, JSCodeGenerator *cg, jssrcnote *notes);
541 /*
542 * Allocate cg->treeContext.tryCount notes (plus one for the end sentinel)
543 * from cx->tempPool and set up cg->tryBase/tryNext for exactly tryCount
544 * js_NewTryNote calls. The storage is freed by js_FinishCodeGenerator.
545 */
546 extern JSBool
547 js_AllocTryNotes(JSContext *cx, JSCodeGenerator *cg);
549 /*
550 * Grab the next trynote slot in cg, filling it in appropriately.
551 */
552 extern JSTryNote *
553 js_NewTryNote(JSContext *cx, JSCodeGenerator *cg, ptrdiff_t start,
554 ptrdiff_t end, ptrdiff_t catchStart);
556 /*
557 * Finish generating exception information into the space at notes. As with
558 * js_FinishTakingSrcNotes, the caller must use CG_COUNT_FINAL_TRYNOTES(cg) to
559 * preallocate enough space in a JSTryNote[] to pass as the notes parameter of
560 * js_FinishTakingTryNotes.
561 */
562 #define CG_COUNT_FINAL_TRYNOTES(cg, cnt) \
563 JS_BEGIN_MACRO \
564 cnt = ((cg)->tryNext > (cg)->tryBase) \
565 ? PTRDIFF(cg->tryNext, cg->tryBase, JSTryNote) + 1 \
566 : 0; \
567 JS_END_MACRO
569 extern void
570 js_FinishTakingTryNotes(JSContext *cx, JSCodeGenerator *cg, JSTryNote *notes);
572 JS_END_EXTERN_C
574 #endif /* jsemit_h___ */