/* -*- 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 #include "prtypes.h" #include "jsatom.h" #include "jsopcode.h" #include "jsprvtd.h" #include "jspubtd.h" PR_BEGIN_EXTERN_C typedef enum StmtType { 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_DO_LOOP = 6, /* do/while loop statement */ STMT_FOR_LOOP = 7, /* for loop statement */ STMT_FOR_IN_LOOP = 8, /* for/in loop statement */ STMT_WHILE_LOOP = 9 /* while loop statement */ } StmtType; #define STMT_IS_LOOP(stmt) ((stmt)->type >= STMT_DO_LOOP) typedef struct SwitchCase SwitchCase; typedef struct StmtInfo StmtInfo; struct StmtInfo { StmtType 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 */ StmtInfo *down; /* info for enclosing statement */ }; struct SwitchCase { jsval value; ptrdiff_t offset; SwitchCase *next; }; #define SET_STATEMENT_TOP(stmt, top) \ ((stmt)->top = (stmt)->update = (stmt)->breaks = (stmt)->continues = (top)) struct JSCodeGenerator { PRArenaPool *pool; /* pool in which to allocate code */ jsbytecode *base; /* base of JS bytecode vector */ jsbytecode *limit; /* one byte beyond end of bytecode */ jsbytecode *ptr; /* pointer to next free bytecode */ JSAtomList atomList; /* literals indexed for mapping */ JSSymbol *args; /* list of formal argument symbols */ JSSymbol *vars; /* list of local variable symbols */ ptrdiff_t lastCodeOffset; /* offset of last non-nop opcode */ StmtInfo *stmtInfo; /* statement stack for break/continue */ 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 */ uintN lastNoteCount; /* index of last emitted source note */ uintN saveNoteCount; /* saved index for source note cancellation */ ptrdiff_t lastNoteOffset; /* code offset of last emitted source note */ ptrdiff_t saveNoteOffset; /* saved offset before last cancellable note */ }; #define CG_CODE(cg,offset) ((cg)->base + (offset)) #define CG_OFFSET(cg) ((cg)->ptr - (cg)->base) #define CG_RESET(cg) ((cg)->ptr = (cg)->base, \ INIT_ATOM_LIST(&(cg)->atomList), \ (cg)->args = (cg)->vars = NULL, \ (cg)->lastCodeOffset = 0, \ (cg)->stmtInfo = NULL, \ (cg)->stackDepth = (cg)->maxStackDepth = 0, \ CG_RESET_NOTES(cg)) #define CG_RESET_NOTES(cg) ((cg)->notes = NULL, (cg)->noteCount = 0, \ (cg)->lastNoteCount = 0, \ (cg)->saveNoteCount = 0, \ (cg)->lastNoteOffset = 0, \ (cg)->saveNoteOffset = 0) #define CG_PUSH(cg, newcg) ((newcg)->atomList = (cg)->atomList) #define CG_POP(cg, newcg) ((cg)->atomList = (newcg)->atomList) /* * Initialize cg to allocate from an arena pool. Return true on success. * Report an exception and return false if the initial code segment can't * be allocated. */ extern JS_FRIEND_API(JSBool) js_InitCodeGenerator(JSContext *cx, JSCodeGenerator *cg, PRArenaPool *pool); /* * 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); /* * 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); /* * Cancel the last bytecode and any immediate operands emitted via cg. * You can't Cancel more than once between Emit calls. */ extern void js_CancelLastOpcode(JSContext *cx, JSCodeGenerator *cg, uint16 *newlinesp); /* * Update cg's stack depth budget for the opcode located at offset in cg. */ extern void js_UpdateDepth(JSContext *cx, JSCodeGenerator *cg, ptrdiff_t offset); /* * Copy code from code generator from starting at fromOffset and running to * CG_OFFSET(from) into code generator to, starting at toOffset. * * NB: this function does not move source notes; the caller must do that. */ extern ptrdiff_t js_MoveCode(JSContext *cx, JSCodeGenerator *from, ptrdiff_t fromOffset, JSCodeGenerator *to, ptrdiff_t toOffset); /* * Push the stack-allocated struct at stmt onto the cg->stmtInfo stack. */ extern void js_PushStatement(JSCodeGenerator *cg, StmtInfo *stmt, StmtType type, ptrdiff_t top); /* * Emit a break instruction, recording it for backpatching. */ extern ptrdiff_t js_EmitBreak(JSContext *cx, JSCodeGenerator *cg, StmtInfo *stmt, JSAtom *label); /* * Emit a continue instruction, recording it for backpatching. */ extern ptrdiff_t js_EmitContinue(JSContext *cx, JSCodeGenerator *cg, StmtInfo *stmt, JSAtom *label); /* * Pop cg->stmtInfo. If the top StmtInfo struct is not stack-allocated, it * is up to the caller to free it. */ extern JSBool js_PopStatement(JSContext *cx, JSCodeGenerator *cg); /* * 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 * in note bytes or byte-pairs. * * 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, /* JSOP_LEAVEWITH for break/continue in with */ 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 */ SRC_UNUSED19 = 19, /* unused */ SRC_UNUSED20 = 20, /* unused */ SRC_UNUSED21 = 21, /* unused */ 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 * [0,127] consumes one byte, an offset in [128,32767] takes two, and the high * bit of the first byte is set. */ #define SN_2BYTE_OFFSET_FLAG 0x80 #define SN_2BYTE_OFFSET_MASK 0x7f extern const char *js_SrcNoteName[]; extern uint8 js_SrcNoteArity[]; extern 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); /* * Increment the delta of the note at cg->notes[index], overflowing into one * or more xdelta notes if necessary. */ extern JSBool js_BumpSrcNoteDelta(JSContext *cx, JSCodeGenerator *cg, uintN index, ptrdiff_t incr); /* * Get and set the offset operand identified by which (0 for the first, etc.). */ extern ptrdiff_t js_GetSrcNoteOffset(jssrcnote *sn, uintN which); extern JSBool js_SetSrcNoteOffset(JSContext *cx, JSCodeGenerator *cg, uintN index, uintN which, ptrdiff_t offset); /* * Copy source notes from one code generator to another. The code annotated * by the copied notes must be moved *after* the notes are moved. */ extern JSBool js_MoveSrcNotes(JSContext *cx, JSCodeGenerator *from, JSCodeGenerator *to); /* * 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); PR_END_EXTERN_C #endif /* jsemit_h___ */