/* -*- 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 1.1 (the "License"); you may not use this file * except in compliance with the License. You may obtain a copy of * the License at http://www.mozilla.org/NPL/ * * Software distributed under the License is distributed on an "AS * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or * implied. See the License for the specific language governing * rights and limitations under the License. * * The Original Code is Mozilla Communicator client code, released * March 31, 1998. * * The Initial Developer of the Original Code is Netscape * Communications Corporation. Portions created by Netscape are * Copyright (C) 1998 Netscape Communications Corporation. All * Rights Reserved. * * Contributor(s): * * Alternatively, the contents of this file may be used under the * terms of the GNU Public License (the "GPL"), in which case the * provisions of the GPL are applicable instead of those above. * If you wish to allow use of your version of this file only * under the terms of the GPL and not to allow others to use your * version of this file under the NPL, indicate your decision by * deleting the provisions above and replace them with the notice * and other provisions required by the GPL. If you do not delete * the provisions above, a recipient may use your version of this * file under either the NPL or the GPL. */ #ifndef jsemit_h___ #define jsemit_h___ /* * JS bytecode generation. */ #include "jsstddef.h" #include "jstypes.h" #include "jsatom.h" #include "jsopcode.h" #include "jsprvtd.h" #include "jspubtd.h" JS_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 clause of if 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 */ STMT_SUBROUTINE = 13 /* gosub-target subroutine body */ } JSStmtType; #define STMT_IS_LOOP(stmt) ((stmt)->type >= STMT_DO_LOOP) typedef struct JSStmtInfo JSStmtInfo; struct JSStmtInfo { JSStmtType type; /* statement type */ 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 */ ptrdiff_t gosub; /* offset of last GOSUB for this finally */ ptrdiff_t catchJump; /* offset of last end-of-catch jump */ JSAtom *label; /* name of LABEL or CATCH var */ JSStmtInfo *down; /* info for enclosing statement */ }; #define SET_STATEMENT_TOP(stmt, top) \ ((stmt)->update = (top), (stmt)->breaks = \ (stmt)->continues = (stmt)->catchJump = (stmt)->gosub = (-1)) 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 */ JSAtomList decls; /* function, const, and var declarations */ JSParseNode *nodeList; /* list of recyclable parse-node structs */ }; #define TCF_COMPILING 0x01 /* generating bytecode; this tc is a cg */ #define TCF_IN_FUNCTION 0x02 /* parsing inside function body */ #define TCF_RETURN_EXPR 0x04 /* function has 'return expr;' */ #define TCF_RETURN_VOID 0x08 /* function has 'return;' */ #define TCF_IN_FOR_INIT 0x10 /* parsing init expr of for; exclude 'in' */ #define TCF_FUN_CLOSURE_VS_VAR 0x20 /* function and var with same name */ #define TCF_FUN_USES_NONLOCALS 0x40 /* function refers to non-local names */ #define TCF_FUN_HEAVYWEIGHT 0x80 /* function needs Call object per call */ #define TCF_FUN_FLAGS 0xE0 /* flags to propagate from FunctionBody */ #define TREE_CONTEXT_INIT(tc) \ ((tc)->flags = 0, (tc)->tryCount = 0, (tc)->topStmt = NULL, \ ATOM_LIST_INIT(&(tc)->decls), (tc)->nodeList = NULL) #define TREE_CONTEXT_FINISH(tc) \ ((void)0) /* * Span-dependent instructions are jumps whose span (from the jump bytecode to * the jump target) may require 2 or 4 bytes of immediate operand. */ typedef struct JSSpanDep JSSpanDep; typedef struct JSJumpTarget JSJumpTarget; struct JSSpanDep { ptrdiff_t top; /* offset of first bytecode in an opcode */ ptrdiff_t offset; /* offset - 1 within opcode of jump operand */ ptrdiff_t before; /* original offset - 1 of jump operand */ JSJumpTarget *target; /* tagged target pointer or backpatch delta */ }; /* * Jump targets are stored in an AVL tree, for O(log(n)) lookup with targets * sorted by offset from left to right, so that targets above a span-dependent * instruction whose jump offset operand must be extended can be found quickly * and adjusted upward (toward higher offsets). */ struct JSJumpTarget { ptrdiff_t offset; /* offset of span-dependent jump target */ int balance; /* AVL tree balance number */ JSJumpTarget *kids[2]; /* left and right AVL tree child pointers */ }; #define JT_LEFT 0 #define JT_RIGHT 1 #define JT_OTHER_DIR(dir) (1 - (dir)) #define JT_IMBALANCE(dir) (((dir) << 1) - 1) #define JT_DIR(imbalance) (((imbalance) + 1) >> 1) /* * Backpatch deltas are encoded in JSSpanDep.target if JT_TAG_BIT is clear, * so we can maintain backpatch chains when using span dependency records to * hold jump offsets that overflow 16 bits. */ #define JT_TAG_BIT ((jsword) 1) #define JT_UNTAG_SHIFT 1 #define JT_SET_TAG(jt) ((JSJumpTarget *)((jsword)(jt) | JT_TAG_BIT)) #define JT_CLR_TAG(jt) ((JSJumpTarget *)((jsword)(jt) & ~JT_TAG_BIT)) #define JT_HAS_TAG(jt) ((jsword)(jt) & JT_TAG_BIT) #define BITS_PER_PTRDIFF (sizeof(ptrdiff_t) * JS_BITS_PER_BYTE) #define BITS_PER_BPDELTA (BITS_PER_PTRDIFF - 1 - JT_UNTAG_SHIFT) #define BPDELTA_MAX ((ptrdiff_t)(JS_BIT(BITS_PER_BPDELTA) - 1)) #define BPDELTA_TO_TN(bp) ((JSJumpTarget *)((bp) << JT_UNTAG_SHIFT)) #define JT_TO_BPDELTA(jt) ((ptrdiff_t)((jsword)(jt) >> JT_UNTAG_SHIFT)) #define SD_SET_TARGET(sd,jt) ((sd)->target = JT_SET_TAG(jt)) #define SD_SET_BPDELTA(sd,bp) ((sd)->target = BPDELTA_TO_TN(bp)) #define SD_GET_BPDELTA(sd) (JS_ASSERT(!JT_HAS_TAG((sd)->target)), \ JT_TO_BPDELTA((sd)->target)) #define SD_TARGET_OFFSET(sd) (JS_ASSERT(JT_HAS_TAG((sd)->target)), \ JT_CLR_TAG((sd)->target)->offset) struct JSCodeGenerator { JSTreeContext treeContext; /* base state: statement info stack, etc. */ void *codeMark; /* low watermark in cx->codePool */ void *noteMark; /* low watermark in cx->notePool */ void *tempMark; /* low watermark in cx->tempPool */ struct { jsbytecode *base; /* base of JS bytecode vector */ jsbytecode *limit; /* one byte beyond end of bytecode */ jsbytecode *next; /* pointer to next free bytecode */ } prolog, main, *current; 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 */ JSAtomList atomList; /* literals indexed for mapping */ intN stackDepth; /* current stack depth in script frame */ uintN maxStackDepth; /* maximum stack depth so far */ jssrcnote *notes; /* source notes, see below */ uintN noteCount; /* number of source notes so far */ uintN noteMask; /* growth increment for notes */ ptrdiff_t lastNoteOffset; /* code offset for last source note */ JSTryNote *tryBase; /* first exception handling note */ JSTryNote *tryNext; /* next available note */ size_t tryNoteSpace; /* # of bytes allocated at tryBase */ JSSpanDep *spanDeps; /* span dependent instruction records */ JSJumpTarget *jumpTargets; /* AVL tree of jump target offsets */ JSJumpTarget *jtFreeList; /* JT_LEFT-linked list of free structs */ uintN numSpanDeps; /* number of span dependencies */ uintN numJumpTargets; /* number of jump targets */ uintN emitLevel; /* js_EmitTree recursion level */ }; #define CG_BASE(cg) ((cg)->current->base) #define CG_LIMIT(cg) ((cg)->current->limit) #define CG_NEXT(cg) ((cg)->current->next) #define CG_CODE(cg,offset) (CG_BASE(cg) + (offset)) #define CG_OFFSET(cg) PTRDIFF(CG_NEXT(cg), CG_BASE(cg), jsbytecode) #define CG_PROLOG_BASE(cg) ((cg)->prolog.base) #define CG_PROLOG_LIMIT(cg) ((cg)->prolog.limit) #define CG_PROLOG_NEXT(cg) ((cg)->prolog.next) #define CG_PROLOG_CODE(cg,poff) (CG_PROLOG_BASE(cg) + (poff)) #define CG_PROLOG_OFFSET(cg) PTRDIFF(CG_PROLOG_NEXT(cg), CG_PROLOG_BASE(cg),\ jsbytecode) #define CG_SWITCH_TO_MAIN(cg) ((cg)->current = &(cg)->main) #define CG_SWITCH_TO_PROLOG(cg) ((cg)->current = &(cg)->prolog) /* * Initialize cg to allocate bytecode space from cx->codePool, source note * space from cx->notePool, and all other arena-allocated temporaries 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, cx->notePool, and cx->tempPool to marks set by * js_InitCodeGenerator. Note that cgs are magic: they own the arena pool * "tops-of-stack" space above their codeMark, noteMark, and tempMark points. * This means you cannot alloc from tempPool and save the pointer beyond the * next JS_FinishCodeGenerator. */ extern JS_FRIEND_API(void) js_FinishCodeGenerator(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) \ JS_BEGIN_MACRO \ if (!js_SetJumpOffset(cx, cg, pc, off)) \ return JS_FALSE; \ JS_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); /* Test whether we're in a with statement. */ extern JSBool js_InWithStatement(JSTreeContext *tc); /* Test whether we're in a catch block with exception named by atom. */ extern JSBool js_InCatchBlock(JSTreeContext *tc, JSAtom *atom); /* * 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); /* * 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. * * Source Note Extended Delta * +7-6-5-4-3+2-1-0+ +7-6-5+4-3-2-1-0+ * |note-type|delta| |1 1| ext-delta | * +---------+-----+ +---+-----------+ * * 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_SrcNoteSpec array in jsemit.c is indexed by this enum, so its * 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; also used on JSOP_ENDINIT if extra comma at end of array literal: [1,2,,] */ SRC_VAR = 6, /* JSOP_NAME/SETNAME/FORNAME in a var decl */ SRC_PCDELTA = 7, /* offset from comma-operator to next POP, or from CONDSWITCH to first CASE opcode */ SRC_ASSIGNOP = 8, /* += or another assign-op follows */ SRC_COND = 9, /* JSOP_IFEQ is from conditional ?: operator */ SRC_RESERVED0 = 10, /* reserved for future use */ 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_CATCH = 20, /* catch block has guard */ SRC_CONST = 21, /* JSOP_SETCONST in a const decl */ 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 (JS_BITMASK(SN_TYPE_BITS) << SN_DELTA_BITS) #define SN_DELTA_MASK ((ptrdiff_t)JS_BITMASK(SN_DELTA_BITS)) #define SN_XDELTA_MASK ((ptrdiff_t)JS_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)JS_BIT(SN_DELTA_BITS)) #define SN_XDELTA_LIMIT ((ptrdiff_t)JS_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 typedef struct JSSrcNoteSpec { const char *name; /* name for disassembly/debugging output */ uint8 arity; /* number of offset operands */ uint8 offsetBias; /* bias of offset(s) from annotated pc */ int8 isSpanDep; /* 1 or -1 if offsets could span extended ops, 0 otherwise; sign tells span direction */ } JSSrcNoteSpec; extern JS_FRIEND_DATA(JSSrcNoteSpec) js_SrcNoteSpec[]; extern JS_FRIEND_API(uintN) js_SrcNoteLength(jssrcnote *sn); #define SN_LENGTH(sn) ((js_SrcNoteSpec[SN_TYPE(sn)].arity == 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); /* * NB: this function can add at most one extra extended delta note. */ extern jssrcnote * js_AddToSrcNoteDelta(JSContext *cx, JSCodeGenerator *cg, jssrcnote *sn, ptrdiff_t delta); /* * 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 notePool by copying them to new * stable store allocated via JS_malloc. Return null on malloc failure, * which means this function reported an error. */ extern jssrcnote * js_FinishTakingSrcNotes(JSContext *cx, JSCodeGenerator *cg); /* * Allocate cg->treeContext.tryCount notes (plus one for the end sentinel) * from cx->tempPool and set up cg->tryBase/tryNext for exactly tryCount * js_NewTryNote calls. The storage is freed by js_FinishCodeGenerator. */ extern JSBool js_AllocTryNotes(JSContext *cx, JSCodeGenerator *cg); /* * Grab the next trynote slot in cg, filling it in appropriately. */ extern 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 JSBool js_FinishTakingTryNotes(JSContext *cx, JSCodeGenerator *cg, JSTryNote **tryp); JS_END_EXTERN_C #endif /* jsemit_h___ */