pjs/js/ref/jsemit.h

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C

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
* Reserved.
*/
#ifndef jsemit_h___
#define jsemit_h___
/*
* JS bytecode generation.
*/
#include "jsstddef.h"
#include "prtypes.h"
#include "jsatom.h"
#include "jsopcode.h"
#include "jsprvtd.h"
#include "jspubtd.h"
PR_BEGIN_EXTERN_C
typedef enum JSStmtType {
STMT_BLOCK = 0, /* compound statement: { s1[;... sN] } */
STMT_LABEL = 1, /* labeled statement: l: s */
STMT_IF = 2, /* if (then) statement */
STMT_ELSE = 3, /* else statement */
STMT_SWITCH = 4, /* switch statement */
STMT_WITH = 5, /* with statement */
STMT_TRY = 6, /* try statement */
STMT_CATCH = 7, /* catch block */
STMT_FINALLY = 8, /* finally statement */
STMT_DO_LOOP = 9, /* do/while loop statement */
STMT_FOR_LOOP = 10, /* for loop statement */
STMT_FOR_IN_LOOP = 11, /* for/in loop statement */
STMT_WHILE_LOOP = 12 /* while loop statement */
} JSStmtType;
#define STMT_IS_LOOP(stmt) ((stmt)->type >= STMT_DO_LOOP)
typedef struct JSStmtInfo JSStmtInfo;
struct JSStmtInfo {
JSStmtType type; /* statement type */
ptrdiff_t top; /* offset of loop top from cg base */
ptrdiff_t update; /* loop update offset (top if none) */
ptrdiff_t breaks; /* offset of last break in loop */
ptrdiff_t continues; /* offset of last continue in loop */
JSAtom *label; /* label name if type is STMT_LABEL */
JSStmtInfo *down; /* info for enclosing statement */
};
#define SET_STATEMENT_TOP(stmt, top) \
((stmt)->top = (stmt)->update = (stmt)->breaks = (stmt)->continues = (top))
struct JSTreeContext { /* tree context for semantic checks */
uint32 flags; /* statement state flags, see below */
uint32 tryCount; /* total count of try statements parsed */
JSStmtInfo *topStmt; /* top of statement info stack */
};
#define TCF_IN_FUNCTION 0x01 /* parsing inside function body */
#define TCF_RETURN_EXPR 0x02 /* function has 'return expr;' */
#define TCF_RETURN_VOID 0x04 /* function has 'return;' */
#define TCF_IN_FOR_INIT 0x08 /* parsing init expr of for; exclude 'in' */
#define TREE_CONTEXT_INIT(tc) \
((tc)->flags = 0, (tc)->tryCount = 0, (tc)->topStmt = NULL)
struct JSCodeGenerator {
void *codeMark; /* low watermark in cx->codePool */
void *tempMark; /* low watermark in cx->tempPool */
jsbytecode *base; /* base of JS bytecode vector */
jsbytecode *limit; /* one byte beyond end of bytecode */
jsbytecode *next; /* pointer to next free bytecode */
const char *filename; /* null or weak link to source filename */
uintN firstLine; /* first line, for js_NewScriptFromCG */
uintN currentLine; /* line number for tree-based srcnote gen */
JSPrincipals *principals; /* principals for constant folding eval */
JSTreeContext treeContext; /* for break/continue code generation */
JSAtomList atomList; /* literals indexed for mapping */
intN stackDepth; /* current stack depth in basic block */
uintN maxStackDepth; /* maximum stack depth so far */
jssrcnote *notes; /* source notes, see below */
uintN noteCount; /* number of source notes so far */
ptrdiff_t lastNoteOffset; /* code offset for last source note */
JSTryNote *tryBase; /* first exception handling note */
JSTryNote *tryLimit; /* pointer to one-past-end note */
JSTryNote *tryNext; /* next available note */
};
#define CG_CODE(cg,offset) ((cg)->base + (offset))
#define CG_OFFSET(cg) PTRDIFF((cg)->next, (cg)->base, jsbytecode)
/*
* Initialize cg to allocate bytecode space from cx->codePool, and srcnote
* space from cx->tempPool. Return true on success. Report an error and
* return false if the initial code segment can't be allocated.
*/
extern JS_FRIEND_API(JSBool)
js_InitCodeGenerator(JSContext *cx, JSCodeGenerator *cg,
const char *filename, uintN lineno,
JSPrincipals *principals);
/*
* Release cx->codePool and cx->tempPool to marks set by js_InitCodeGenerator.
*/
extern JS_FRIEND_API(void)
js_ResetCodeGenerator(JSContext *cx, JSCodeGenerator *cg);
/*
* Emit one bytecode.
*/
extern ptrdiff_t
js_Emit1(JSContext *cx, JSCodeGenerator *cg, JSOp op);
/*
* Emit two bytecodes, an opcode (op) with a byte of immediate operand (op1).
*/
extern ptrdiff_t
js_Emit2(JSContext *cx, JSCodeGenerator *cg, JSOp op, jsbytecode op1);
/*
* Emit three bytecodes, an opcode with two bytes of immediate operands.
*/
extern ptrdiff_t
js_Emit3(JSContext *cx, JSCodeGenerator *cg, JSOp op, jsbytecode op1,
jsbytecode op2);
/*
* Emit (1 + extra) bytecodes, for N bytes of op and its immediate operand.
*/
extern ptrdiff_t
js_EmitN(JSContext *cx, JSCodeGenerator *cg, JSOp op, size_t extra);
/*
* Unsafe macro to call js_SetJumpOffset and return false if it does.
*/
#define CHECK_AND_SET_JUMP_OFFSET(cx,cg,pc,off) \
PR_BEGIN_MACRO \
if (!js_SetJumpOffset(cx, cg, pc, off)) \
return JS_FALSE; \
PR_END_MACRO
#define CHECK_AND_SET_JUMP_OFFSET_AT(cx,cg,off) \
CHECK_AND_SET_JUMP_OFFSET(cx, cg, CG_CODE(cg,off), CG_OFFSET(cg) - (off))
extern JSBool
js_SetJumpOffset(JSContext *cx, JSCodeGenerator *cg, jsbytecode *pc,
ptrdiff_t off);
/*
* Push the C-stack-allocated struct at stmt onto the stmtInfo stack.
*/
extern void
js_PushStatement(JSTreeContext *tc, JSStmtInfo *stmt, JSStmtType type,
ptrdiff_t top);
/*
* Emit a break instruction, recording it for backpatching.
*/
extern ptrdiff_t
js_EmitBreak(JSContext *cx, JSCodeGenerator *cg, JSStmtInfo *stmt,
JSAtomListElement *label);
/*
* Emit a continue instruction, recording it for backpatching.
*/
extern ptrdiff_t
js_EmitContinue(JSContext *cx, JSCodeGenerator *cg, JSStmtInfo *stmt,
JSAtomListElement *label);
/*
* Pop tc->topStmt. If the top JSStmtInfo struct is not stack-allocated, it
* is up to the caller to free it.
*/
extern void
js_PopStatement(JSTreeContext *tc);
/*
* Like js_PopStatement(&cg->treeContext), also patch breaks and continues.
* May fail if a jump offset overflows.
*/
extern JSBool
js_PopStatementCG(JSContext *cx, JSCodeGenerator *cg);
/*
* Emit code into cg for the tree rooted at pn.
*/
extern JSBool
js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn);
/*
* Emit code into cg for the tree rooted at body, then create a persistent
* script for fun from cg.
*/
extern JSBool
js_EmitFunctionBody(JSContext *cx, JSCodeGenerator *cg, JSParseNode *body,
JSFunction *fun);
/*
* Source notes generated along with bytecode for decompiling and debugging.
* A source note is a uint8 with 5 bits of type and 3 of offset from the pc of
* the previous note. If 3 bits of offset aren't enough, extended delta notes
* (SRC_XDELTA) consisting of 2 set high order bits followed by 6 offset bits
* are emitted before the next note. Some notes have operand offsets encoded
* immediately after them, in note bytes or byte-triples.
*
* At most one "gettable" note (i.e., a note of type other than SRC_NEWLINE,
* SRC_SETLINE, and SRC_XDELTA) applies to a given bytecode.
*
* NB: the js_SrcNoteName and js_SrcNoteArity arrays in jsemit.c are indexed
* by this enum, so their initializers need to match the order here.
*/
typedef enum JSSrcNoteType {
SRC_NULL = 0, /* terminates a note vector */
SRC_IF = 1, /* JSOP_IFEQ bytecode is from an if-then */
SRC_IF_ELSE = 2, /* JSOP_IFEQ bytecode is from an if-then-else */
SRC_WHILE = 3, /* JSOP_IFEQ is from a while loop */
SRC_FOR = 4, /* JSOP_NOP or JSOP_POP in for loop head */
SRC_CONTINUE = 5, /* JSOP_GOTO is a continue, not a break */
SRC_VAR = 6, /* JSOP_NAME/FORNAME with a var declaration */
SRC_COMMA = 7, /* JSOP_POP representing a comma operator */
SRC_ASSIGNOP = 8, /* += or another assign-op follows */
SRC_COND = 9, /* JSOP_IFEQ is from conditional ?: operator */
SRC_PAREN = 10, /* JSOP_NOP generated to mark user parens */
SRC_HIDDEN = 11, /* opcode shouldn't be decompiled */
SRC_PCBASE = 12, /* offset of first obj.prop.subprop bytecode */
SRC_LABEL = 13, /* JSOP_NOP for label: with atomid immediate */
SRC_LABELBRACE = 14, /* JSOP_NOP for label: {...} begin brace */
SRC_ENDBRACE = 15, /* JSOP_NOP for label: {...} end brace */
SRC_BREAK2LABEL = 16, /* JSOP_GOTO for 'break label' with atomid */
SRC_CONT2LABEL = 17, /* JSOP_GOTO for 'continue label' with atomid */
SRC_SWITCH = 18, /* JSOP_*SWITCH with offset to end of switch,
2nd off to first JSOP_CASE if condswitch */
SRC_FUNCDEF = 19, /* JSOP_NOP for function f() with atomid */
SRC_TRYFIN = 20, /* JSOP_NOP for try or finally section */
SRC_CATCH = 21, /* catch block has guard */
SRC_NEWLINE = 22, /* bytecode follows a source newline */
SRC_SETLINE = 23, /* a file-absolute source line number note */
SRC_XDELTA = 24 /* 24-31 are for extended delta notes */
} JSSrcNoteType;
#define SN_TYPE_BITS 5
#define SN_DELTA_BITS 3
#define SN_XDELTA_BITS 6
#define SN_TYPE_MASK (PR_BITMASK(SN_TYPE_BITS) << SN_DELTA_BITS)
#define SN_DELTA_MASK ((ptrdiff_t)PR_BITMASK(SN_DELTA_BITS))
#define SN_XDELTA_MASK ((ptrdiff_t)PR_BITMASK(SN_XDELTA_BITS))
#define SN_MAKE_NOTE(sn,t,d) (*(sn) = (jssrcnote) \
(((t) << SN_DELTA_BITS) \
| ((d) & SN_DELTA_MASK)))
#define SN_MAKE_XDELTA(sn,d) (*(sn) = (jssrcnote) \
((SRC_XDELTA << SN_DELTA_BITS) \
| ((d) & SN_XDELTA_MASK)))
#define SN_IS_XDELTA(sn) ((*(sn) >> SN_DELTA_BITS) >= SRC_XDELTA)
#define SN_TYPE(sn) (SN_IS_XDELTA(sn) ? SRC_XDELTA \
: *(sn) >> SN_DELTA_BITS)
#define SN_SET_TYPE(sn,type) SN_MAKE_NOTE(sn, type, SN_DELTA(sn))
#define SN_IS_GETTABLE(sn) (SN_TYPE(sn) < SRC_NEWLINE)
#define SN_DELTA(sn) ((ptrdiff_t)(SN_IS_XDELTA(sn) \
? *(sn) & SN_XDELTA_MASK \
: *(sn) & SN_DELTA_MASK))
#define SN_SET_DELTA(sn,delta) (SN_IS_XDELTA(sn) \
? SN_MAKE_XDELTA(sn, delta) \
: SN_MAKE_NOTE(sn, SN_TYPE(sn), delta))
#define SN_DELTA_LIMIT ((ptrdiff_t)PR_BIT(SN_DELTA_BITS))
#define SN_XDELTA_LIMIT ((ptrdiff_t)PR_BIT(SN_XDELTA_BITS))
/*
* Offset fields follow certain notes and are frequency-encoded: an offset in
* [0,0x7f] consumes one byte, an offset in [0x80,0x7fffff] takes three, and
* the high bit of the first byte is set.
*/
#define SN_3BYTE_OFFSET_FLAG 0x80
#define SN_3BYTE_OFFSET_MASK 0x7f
extern JS_FRIEND_DATA(const char *) js_SrcNoteName[];
extern JS_FRIEND_DATA(uint8) js_SrcNoteArity[];
extern JS_FRIEND_DATA(uintN) js_SrcNoteLength(jssrcnote *sn);
#define SN_LENGTH(sn) ((js_SrcNoteArity[SN_TYPE(sn)] == 0) ? 1 \
: js_SrcNoteLength(sn))
#define SN_NEXT(sn) ((sn) + SN_LENGTH(sn))
/* A source note array is terminated by an all-zero element. */
#define SN_MAKE_TERMINATOR(sn) (*(sn) = SRC_NULL)
#define SN_IS_TERMINATOR(sn) (*(sn) == SRC_NULL)
/*
* Append a new source note of the given type (and therefore size) to cg's
* notes dynamic array, updating cg->noteCount. Return the new note's index
* within the array pointed at by cg->notes. Return -1 if out of memory.
*/
extern intN
js_NewSrcNote(JSContext *cx, JSCodeGenerator *cg, JSSrcNoteType type);
extern intN
js_NewSrcNote2(JSContext *cx, JSCodeGenerator *cg, JSSrcNoteType type,
ptrdiff_t offset);
extern intN
js_NewSrcNote3(JSContext *cx, JSCodeGenerator *cg, JSSrcNoteType type,
ptrdiff_t offset1, ptrdiff_t offset2);
/*
* Get and set the offset operand identified by which (0 for the first, etc.).
*/
extern JS_FRIEND_API(ptrdiff_t)
js_GetSrcNoteOffset(jssrcnote *sn, uintN which);
extern JSBool
js_SetSrcNoteOffset(JSContext *cx, JSCodeGenerator *cg, uintN index,
uintN which, ptrdiff_t offset);
/*
* Finish taking source notes in cx's tempPool by copying them to new
* stable store allocated via JS_malloc. Return null on malloc failure,
* which means this function reported an error.
*/
extern JS_FRIEND_API(jssrcnote *)
js_FinishTakingSrcNotes(JSContext *cx, JSCodeGenerator *cg);
/*
* Allocate cg->treeContext.tryCount notes (plus one for the end sentinel)
* from cx->tempPool and set cg->tryBase/tryNext/tryLimit for exactly tryCount
* js_NewTryNote calls. The storage is freed by js_ResetCodeGenerator.
*/
extern JSBool
js_AllocTryNotes(JSContext *cx, JSCodeGenerator *cg);
/*
* Grab the next trynote slot in cg, filling it in appropriately.
*/
extern JS_FRIEND_API(JSTryNote *)
js_NewTryNote(JSContext *cx, JSCodeGenerator *cg, ptrdiff_t start,
ptrdiff_t end, ptrdiff_t catchStart);
/*
* Finish generating exception information, and copy it to JS_malloc
* storage.
*/
extern JS_FRIEND_API(JSBool)
js_FinishTakingTryNotes(JSContext *cx, JSCodeGenerator *cg, JSTryNote **tryp);
PR_END_EXTERN_C
#endif /* jsemit_h___ */