/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- * vim: set ts=4 sw=4 et tw=79 ft=cpp: * * ***** BEGIN LICENSE BLOCK ***** * Version: MPL 1.1/GPL 2.0/LGPL 2.1 * * The contents of this file are subject to the Mozilla 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/MPL/ * * 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 the Initial Developer are Copyright (C) 1998 * the Initial Developer. All Rights Reserved. * * Contributor(s): * * Alternatively, the contents of this file may be used under the terms of * either of the GNU General Public License Version 2 or later (the "GPL"), * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), * in which case the provisions of the GPL or the LGPL are applicable instead * of those above. If you wish to allow use of your version of this file only * under the terms of either the GPL or the LGPL, and not to allow others to * use your version of this file under the terms of the MPL, indicate your * decision by deleting the provisions above and replace them with the notice * and other provisions required by the GPL or the LGPL. If you do not delete * the provisions above, a recipient may use your version of this file under * the terms of any one of the MPL, the GPL or the LGPL. * * ***** END LICENSE BLOCK ***** */ #ifndef jsscript_h___ #define jsscript_h___ /* * JS script descriptor. */ #include "jsatom.h" #include "jsprvtd.h" #include "jsdbgapi.h" #include "jsclist.h" /* * Type of try note associated with each catch or finally block, and also with * for-in loops. */ typedef enum JSTryNoteKind { JSTRY_CATCH, JSTRY_FINALLY, JSTRY_ITER } JSTryNoteKind; namespace js { /* * Indicates a location in the stack that an upvar value can be retrieved from * as a two tuple of (level, slot). * * Some existing client code uses the level value as a delta, or level "skip" * quantity. We could probably document that through use of more types at some * point in the future. * * Existing XDR code wants this to be backed by a 32b integer for serialization, * so we oblige. * * TODO: consider giving more bits to the slot value and takings ome from the level. */ class UpvarCookie { uint32 value; static const uint32 FREE_VALUE = 0xfffffffful; void checkInvariants() { JS_STATIC_ASSERT(sizeof(UpvarCookie) == sizeof(uint32)); JS_STATIC_ASSERT(UPVAR_LEVEL_LIMIT < FREE_LEVEL); } public: /* * All levels above-and-including FREE_LEVEL are reserved so that * FREE_VALUE can be used as a special value. */ static const uint16 FREE_LEVEL = 0x3fff; /* * If a function has a higher static level than this limit, we will not * optimize it using UPVAR opcodes. */ static const uint16 UPVAR_LEVEL_LIMIT = 16; static const uint16 CALLEE_SLOT = 0xffff; static bool isLevelReserved(uint16 level) { return level >= FREE_LEVEL; } bool isFree() const { return value == FREE_VALUE; } uint32 asInteger() const { return value; } /* isFree check should be performed before using these accessors. */ uint16 level() const { JS_ASSERT(!isFree()); return uint16(value >> 16); } uint16 slot() const { JS_ASSERT(!isFree()); return uint16(value); } void set(const UpvarCookie &other) { set(other.level(), other.slot()); } void set(uint16 newLevel, uint16 newSlot) { value = (uint32(newLevel) << 16) | newSlot; } void makeFree() { set(0xffff, 0xffff); JS_ASSERT(isFree()); } void fromInteger(uint32 u32) { value = u32; } }; } /* * Exception handling record. */ struct JSTryNote { uint8 kind; /* one of JSTryNoteKind */ uint8 padding; /* explicit padding on uint16 boundary */ uint16 stackDepth; /* stack depth upon exception handler entry */ uint32 start; /* start of the try statement or for-in loop relative to script->main */ uint32 length; /* length of the try statement or for-in loop */ }; typedef struct JSTryNoteArray { JSTryNote *vector; /* array of indexed try notes */ uint32 length; /* count of indexed try notes */ } JSTryNoteArray; typedef struct JSObjectArray { JSObject **vector; /* array of indexed objects */ uint32 length; /* count of indexed objects */ } JSObjectArray; typedef struct JSUpvarArray { js::UpvarCookie *vector; /* array of indexed upvar cookies */ uint32 length; /* count of indexed upvar cookies */ } JSUpvarArray; typedef struct JSConstArray { js::Value *vector; /* array of indexed constant values */ uint32 length; } JSConstArray; namespace js { struct GlobalSlotArray { struct Entry { uint32 atomIndex; /* index into atom table */ uint32 slot; /* global obj slot number */ }; Entry *vector; uint32 length; }; } /* namespace js */ #define JS_OBJECT_ARRAY_SIZE(length) \ (offsetof(JSObjectArray, vector) + sizeof(JSObject *) * (length)) #if defined DEBUG && defined JS_THREADSAFE # define CHECK_SCRIPT_OWNER 1 #endif #ifdef JS_METHODJIT namespace JSC { class ExecutablePool; } #define JS_UNJITTABLE_SCRIPT (reinterpret_cast(1)) enum JITScriptStatus { JITScript_None, JITScript_Invalid, JITScript_Valid }; namespace js { namespace mjit { struct JITScript; } } #endif struct JSScript { /* * Two successively less primitive ways to make a new JSScript. The first * does *not* call a non-null cx->runtime->newScriptHook -- only the second, * NewScriptFromCG, calls this optional debugger hook. * * The NewScript function can't know whether the script it creates belongs * to a function, or is top-level or eval code, but the debugger wants access * to the newly made script's function, if any -- so callers of NewScript * are responsible for notifying the debugger after successfully creating any * kind (function or other) of new JSScript. * * NB: NewScript always creates a new script; it never returns the empty * script singleton (JSScript::emptyScript()). Callers who know they can use * that read-only singleton are responsible for choosing it instead of calling * NewScript with length and nsrcnotes equal to 1 and other parameters save * cx all zero. */ static JSScript *NewScript(JSContext *cx, uint32 length, uint32 nsrcnotes, uint32 natoms, uint32 nobjects, uint32 nupvars, uint32 nregexps, uint32 ntrynotes, uint32 nconsts, uint32 nglobals, uint32 nClosedArgs, uint32 nClosedVars); static JSScript *NewScriptFromCG(JSContext *cx, JSCodeGenerator *cg); /* FIXME: bug 586181 */ JSCList links; /* Links for compartment script list */ jsbytecode *code; /* bytecodes and their immediate operands */ uint32 length; /* length of code vector */ uint16 version; /* JS version under which script was compiled */ uint16 nfixed; /* number of slots besides stack operands in slot array */ uint8 objectsOffset; /* offset to the array of nested function, block, scope, xml and one-time regexps objects or 0 if none */ uint8 upvarsOffset; /* offset of the array of display ("up") closure vars or 0 if none */ uint8 regexpsOffset; /* offset to the array of to-be-cloned regexps or 0 if none. */ uint8 trynotesOffset; /* offset to the array of try notes or 0 if none */ uint8 globalsOffset; /* offset to the array of global slots or 0 if none */ uint8 constOffset; /* offset to the array of constants or 0 if none */ bool noScriptRval:1; /* no need for result value of last expression statement */ bool savedCallerFun:1; /* object 0 is caller function */ bool hasSharps:1; /* script uses sharp variables */ bool strictModeCode:1; /* code is in strict mode */ bool compileAndGo:1; /* script was compiled with TCF_COMPILE_N_GO */ bool usesEval:1; /* script uses eval() */ bool usesArguments:1; /* script uses arguments */ bool warnedAboutTwoArgumentEval:1; /* have warned about use of obsolete eval(s, o) in this script */ #ifdef JS_METHODJIT bool debugMode:1; /* script was compiled in debug mode */ #endif jsbytecode *main; /* main entry point, after predef'ing prolog */ JSAtomMap atomMap; /* maps immediate index to literal struct */ JSCompartment *compartment; /* compartment the script was compiled for */ const char *filename; /* source filename or null */ uint32 lineno; /* base line number of script */ uint16 nslots; /* vars plus maximum stack depth */ uint16 staticLevel;/* static level for display maintenance */ uint16 nClosedArgs; /* number of args which are closed over. */ uint16 nClosedVars; /* number of vars which are closed over. */ JSPrincipals *principals;/* principals for this script */ union { /* * A script object of class js_ScriptClass, to ensure the script is GC'd. * - All scripts returned by JSAPI functions (JS_CompileScript, * JS_CompileFile, etc.) have these objects. * - Function scripts never have script objects; such scripts are owned * by their function objects. * - Temporary scripts created by obj_eval, JS_EvaluateScript, and * similar functions never have these objects; such scripts are * explicitly destroyed by the code that created them. * Debugging API functions (JSDebugHooks::newScriptHook; * JS_GetFunctionScript) may reveal sans-script-object Function and * temporary scripts to clients, but clients must never call * JS_NewScriptObject on such scripts: doing so would double-free them, * once from the explicit call to js_DestroyScript, and once when the * script object is garbage collected. */ JSObject *object; JSScript *nextToGC; /* next to GC in rt->scriptsToGC list */ } u; #ifdef CHECK_SCRIPT_OWNER JSThread *owner; /* for thread-safe life-cycle assertions */ #endif uint32 *closedSlots; /* vector of closed slots; args first, then vars. */ public: #ifdef JS_METHODJIT // Fast-cached pointers to make calls faster. These are also used to // quickly test whether there is JIT code; a NULL value means no // compilation has been attempted. A JS_UNJITTABLE_SCRIPT value means // compilation failed. Any value is the arity-check entry point. void *jitArityCheckNormal; void *jitArityCheckCtor; js::mjit::JITScript *jitNormal; /* Extra JIT info for normal scripts */ js::mjit::JITScript *jitCtor; /* Extra JIT info for constructors */ bool hasJITCode() { return jitNormal || jitCtor; } // These methods are implemented in MethodJIT.h. inline void **nativeMap(bool constructing); inline void *maybeNativeCodeForPC(bool constructing, jsbytecode *pc); inline void *nativeCodeForPC(bool constructing, jsbytecode *pc); js::mjit::JITScript *getJIT(bool constructing) { return constructing ? jitCtor : jitNormal; } JITScriptStatus getJITStatus(bool constructing) { void *addr = constructing ? jitArityCheckCtor : jitArityCheckNormal; if (addr == NULL) return JITScript_None; if (addr == JS_UNJITTABLE_SCRIPT) return JITScript_Invalid; return JITScript_Valid; } #endif /* Script notes are allocated right after the code. */ jssrcnote *notes() { return (jssrcnote *)(code + length); } JSObjectArray *objects() { JS_ASSERT(objectsOffset != 0); return (JSObjectArray *)((uint8 *) this + objectsOffset); } JSUpvarArray *upvars() { JS_ASSERT(upvarsOffset != 0); return (JSUpvarArray *) ((uint8 *) this + upvarsOffset); } JSObjectArray *regexps() { JS_ASSERT(regexpsOffset != 0); return (JSObjectArray *) ((uint8 *) this + regexpsOffset); } JSTryNoteArray *trynotes() { JS_ASSERT(trynotesOffset != 0); return (JSTryNoteArray *) ((uint8 *) this + trynotesOffset); } js::GlobalSlotArray *globals() { JS_ASSERT(globalsOffset != 0); return (js::GlobalSlotArray *) ((uint8 *)this + globalsOffset); } JSConstArray *consts() { JS_ASSERT(constOffset != 0); return (JSConstArray *) ((uint8 *) this + constOffset); } JSAtom *getAtom(size_t index) { JS_ASSERT(index < atomMap.length); return atomMap.vector[index]; } JSObject *getObject(size_t index) { JSObjectArray *arr = objects(); JS_ASSERT(index < arr->length); return arr->vector[index]; } uint32 getGlobalSlot(size_t index) { js::GlobalSlotArray *arr = globals(); JS_ASSERT(index < arr->length); return arr->vector[index].slot; } JSAtom *getGlobalAtom(size_t index) { js::GlobalSlotArray *arr = globals(); JS_ASSERT(index < arr->length); return getAtom(arr->vector[index].atomIndex); } JSVersion getVersion() const { return JSVersion(version); } void setVersion(JSVersion newVersion) { JS_ASSERT((newVersion & JS_BITMASK(16)) == uint32(newVersion)); version = newVersion; } inline JSFunction *getFunction(size_t index); inline JSObject *getRegExp(size_t index); const js::Value &getConst(size_t index) { JSConstArray *arr = consts(); JS_ASSERT(index < arr->length); return arr->vector[index]; } /* * The isEmpty method tells whether this script has code that computes any * result (not return value, result AKA normal completion value) other than * JSVAL_VOID, or any other effects. It has a fast path for the case where * |this| is the emptyScript singleton, but it also checks this->length and * this->code, to handle debugger-generated mutable empty scripts. */ inline bool isEmpty() const; /* * Accessor for the emptyScriptConst singleton, to consolidate const_cast. * See the private member declaration. */ static JSScript *emptyScript() { return const_cast(&emptyScriptConst); } uint32 getClosedArg(uint32 index) { JS_ASSERT(index < nClosedArgs); return closedSlots[index]; } uint32 getClosedVar(uint32 index) { JS_ASSERT(index < nClosedVars); return closedSlots[nClosedArgs + index]; } void copyClosedSlotsTo(JSScript *other); private: /* * Use const to put this in read-only memory if possible. We are stuck with * non-const JSScript * and jsbytecode * by legacy code (back in the 1990s, * const wasn't supported correctly on all target platforms). The debugger * does mutate bytecode, and script->u.object may be set after construction * in some cases, so making JSScript pointers const will be "hard". */ static const JSScript emptyScriptConst; }; #define SHARP_NSLOTS 2 /* [#array, #depth] slots if the script uses sharp variables */ static JS_INLINE uintN StackDepth(JSScript *script) { return script->nslots - script->nfixed; } /* * If pc_ does not point within script_'s bytecode, then it must point into an * imacro body, so we use cx->runtime common atoms instead of script_'s atoms. * This macro uses cx from its callers' environments in the pc-in-imacro case. */ #define JS_GET_SCRIPT_ATOM(script_, pc_, index, atom) \ JS_BEGIN_MACRO \ if ((pc_) < (script_)->code || \ (script_)->code + (script_)->length <= (pc_)) { \ JS_ASSERT((size_t)(index) < js_common_atom_count); \ (atom) = COMMON_ATOMS_START(&cx->runtime->atomState)[index]; \ } else { \ (atom) = script_->getAtom(index); \ } \ JS_END_MACRO extern JS_FRIEND_DATA(js::Class) js_ScriptClass; extern JSObject * js_InitScriptClass(JSContext *cx, JSObject *obj); /* * On first new context in rt, initialize script runtime state, specifically * the script filename table and its lock. */ extern JSBool js_InitRuntimeScriptState(JSRuntime *rt); /* * On JS_DestroyRuntime(rt), forcibly free script filename prefixes and any * script filename table entries that have not been GC'd. * * This allows script filename prefixes to outlive any context in rt. */ extern void js_FreeRuntimeScriptState(JSRuntime *rt); extern const char * js_SaveScriptFilename(JSContext *cx, const char *filename); extern const char * js_SaveScriptFilenameRT(JSRuntime *rt, const char *filename, uint32 flags); extern uint32 js_GetScriptFilenameFlags(const char *filename); extern void js_MarkScriptFilename(const char *filename); extern void js_MarkScriptFilenames(JSRuntime *rt); extern void js_SweepScriptFilenames(JSRuntime *rt); /* * New-script-hook calling is factored from js_NewScriptFromCG so that it * and callers of js_XDRScript can share this code. In the case of callers * of js_XDRScript, the hook should be invoked only after successful decode * of any owning function (the fun parameter) or script object (null fun). */ extern JS_FRIEND_API(void) js_CallNewScriptHook(JSContext *cx, JSScript *script, JSFunction *fun); extern JS_FRIEND_API(void) js_CallDestroyScriptHook(JSContext *cx, JSScript *script); extern void js_DestroyScript(JSContext *cx, JSScript *script); extern void js_TraceScript(JSTracer *trc, JSScript *script); extern JSBool js_NewScriptObject(JSContext *cx, JSScript *script); /* * To perturb as little code as possible, we introduce a js_GetSrcNote lookup * cache without adding an explicit cx parameter. Thus js_GetSrcNote becomes * a macro that uses cx from its calls' lexical environments. */ #define js_GetSrcNote(script,pc) js_GetSrcNoteCached(cx, script, pc) extern jssrcnote * js_GetSrcNoteCached(JSContext *cx, JSScript *script, jsbytecode *pc); /* * NOTE: use js_FramePCToLineNumber(cx, fp) when you have an active fp, in * preference to js_PCToLineNumber (cx, fp->script fp->regs->pc), because * fp->imacpc may be non-null, indicating an active imacro. */ extern uintN js_FramePCToLineNumber(JSContext *cx, JSStackFrame *fp); extern uintN js_PCToLineNumber(JSContext *cx, JSScript *script, jsbytecode *pc); extern jsbytecode * js_LineNumberToPC(JSScript *script, uintN lineno); extern JS_FRIEND_API(uintN) js_GetScriptLineExtent(JSScript *script); static JS_INLINE JSOp js_GetOpcode(JSContext *cx, JSScript *script, jsbytecode *pc) { JSOp op = (JSOp) *pc; if (op == JSOP_TRAP) op = JS_GetTrapOpcode(cx, script, pc); return op; } extern JSScript * js_CloneScript(JSContext *cx, JSScript *script); /* * If magic is non-null, js_XDRScript succeeds on magic number mismatch but * returns false in *magic; it reflects a match via a true *magic out param. * If magic is null, js_XDRScript returns false on bad magic number errors, * which it reports. * * NB: after a successful JSXDR_DECODE, and provided that *scriptp is not the * JSScript::emptyScript() immutable singleton, js_XDRScript callers must do * any required subsequent set-up of owning function or script object and then * call js_CallNewScriptHook. * * If the caller requires a mutable empty script (for debugging or u.object * ownership setting), pass true for needMutableScript. Otherwise pass false. * Call js_CallNewScriptHook only with a mutable script, i.e. never with the * JSScript::emptyScript() singleton. */ extern JSBool js_XDRScript(JSXDRState *xdr, JSScript **scriptp, bool needMutableScript, JSBool *hasMagic); #endif /* jsscript_h___ */