/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- * vim: set ts=4 sw=4 et tw=78: * * ***** 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 jsinterp_h___ #define jsinterp_h___ /* * JS interpreter interface. */ #include "jsprvtd.h" #include "jspubtd.h" #include "jsfun.h" #include "jsopcode.h" #include "jsscript.h" JS_BEGIN_EXTERN_C typedef struct JSFrameRegs { jsbytecode *pc; /* program counter */ jsval *sp; /* stack pointer */ } JSFrameRegs; /* JS stack frame flags. */ enum JSFrameFlags { JSFRAME_CONSTRUCTING = 0x01, /* frame is for a constructor invocation */ JSFRAME_OVERRIDE_ARGS = 0x02, /* overridden arguments local variable */ JSFRAME_ASSIGNING = 0x04, /* a complex (not simplex JOF_ASSIGNING) op is currently assigning to a property */ JSFRAME_DEBUGGER = 0x08, /* frame for JS_EvaluateInStackFrame */ JSFRAME_EVAL = 0x10, /* frame for obj_eval */ JSFRAME_FLOATING_GENERATOR = 0x20, /* frame copy stored in a generator obj */ JSFRAME_YIELDING = 0x40, /* js_Interpret dispatched JSOP_YIELD */ JSFRAME_GENERATOR = 0x80, /* frame belongs to generator-iterator */ JSFRAME_SPECIAL = JSFRAME_DEBUGGER | JSFRAME_EVAL }; /* * JS stack frame, may be allocated on the C stack by native callers. Always * allocated on cx->stackPool for calls from the interpreter to an interpreted * function. * * NB: This struct is manually initialized in jsinterp.c and jsiter.c. If you * add new members, update both files. */ struct JSStackFrame { jsbytecode *imacpc; /* null or interpreter macro call pc */ JSObject *callobj; /* lazily created Call object */ jsval argsobj; /* lazily created arguments object, must be JSVAL_OBJECT */ JSScript *script; /* script being interpreted */ JSFunction *fun; /* function being called or null */ /* * The value of |this| in this stack frame, or JSVAL_NULL if |this| is to * be computed lazily on demand. * * thisv is eagerly initialized for non-function-call frames and qualified * method calls, but lazily initialized in most unqualified function calls. * See getThisObject(). * * Usually if argv != NULL then thisv == argv[-1], but natives may assign * to argv[-1]. Also, obj_eval can trigger a special case where two stack * frames have the same argv. If one of the frames fills in both argv[-1] * and thisv, the other frame's thisv is left null. */ jsval thisv; uintN argc; /* actual argument count */ jsval *argv; /* base of argument stack slots */ jsval rval; /* function return value */ void *annotation; /* used by Java security */ /* Maintained by StackSpace operations */ JSStackFrame *down; /* previous frame, part of stack layout invariant */ jsbytecode *savedPC; /* only valid if cx->fp != this */ #ifdef DEBUG static jsbytecode *const sInvalidPC; #endif /* * We can't determine in advance which local variables can live on * the stack and be freed when their dynamic scope ends, and which * will be closed over and need to live in the heap. So we place * variables on the stack initially, note when they are closed * over, and copy those that are out to the heap when we leave * their dynamic scope. * * The bytecode compiler produces a tree of block objects * accompanying each JSScript representing those lexical blocks in * the script that have let-bound variables associated with them. * These block objects are never modified, and never become part * of any function's scope chain. Their parent slots point to the * innermost block that encloses them, or are NULL in the * outermost blocks within a function or in eval or global code. * * When we are in the static scope of such a block, blockChain * points to its compiler-allocated block object; otherwise, it is * NULL. * * scopeChain is the current scope chain, including 'call' and * 'block' objects for those function calls and lexical blocks * whose static scope we are currently executing in, and 'with' * objects for with statements; the chain is typically terminated * by a global object. However, as an optimization, the young end * of the chain omits block objects we have not yet cloned. To * create a closure, we clone the missing blocks from blockChain * (which is always current), place them at the head of * scopeChain, and use that for the closure's scope chain. If we * never close over a lexical block, we never place a mutable * clone of it on scopeChain. * * This lazy cloning is implemented in js_GetScopeChain, which is * also used in some other cases --- entering 'with' blocks, for * example. */ union { JSObject *scopeChain; jsval scopeChainVal; }; JSObject *blockChain; uint32 flags; /* frame flags -- see below */ JSStackFrame *displaySave; /* previous value of display entry for script->staticLevel */ /* Members only needed for inline calls. */ void *hookData; /* debugger call hook data */ JSVersion callerVersion; /* dynamic version of calling script */ void putActivationObjects(JSContext *cx) { /* * The order of calls here is important as js_PutCallObject needs to * access argsobj. */ if (callobj) { js_PutCallObject(cx, this); JS_ASSERT(!argsobj); } else if (argsobj) { js_PutArgsObject(cx, this); } } /* Get the frame's current bytecode, assuming |this| is in |cx|. */ jsbytecode *pc(JSContext *cx) const; jsval *argEnd() const { return (jsval *)this; } jsval *slots() const { return (jsval *)(this + 1); } jsval calleeValue() { JS_ASSERT(argv); return argv[-2]; } JSObject *calleeObject() { JS_ASSERT(argv); return JSVAL_TO_OBJECT(argv[-2]); } JSObject *callee() { return argv ? JSVAL_TO_OBJECT(argv[-2]) : NULL; } /* * Get the object associated with the Execution Context's * VariableEnvironment (ES5 10.3). The given CallStack must contain this * stack frame. */ JSObject *varobj(js::CallStack *cs) const; /* Short for: varobj(cx->activeCallStack()). */ JSObject *varobj(JSContext *cx) const; inline JSObject *getThisObject(JSContext *cx); bool isGenerator() const { return flags & JSFRAME_GENERATOR; } bool isFloatingGenerator() const { if (flags & JSFRAME_FLOATING_GENERATOR) { JS_ASSERT(isGenerator()); return true; } return false; } private: JSObject *computeThisObject(JSContext *cx); }; namespace js { static const size_t VALUES_PER_STACK_FRAME = sizeof(JSStackFrame) / sizeof(jsval); JS_STATIC_ASSERT(sizeof(JSStackFrame) % sizeof(jsval) == 0); } static JS_INLINE jsval * StackBase(JSStackFrame *fp) { return fp->slots() + fp->script->nfixed; } static JS_INLINE uintN GlobalVarCount(JSStackFrame *fp) { JS_ASSERT(!fp->fun); return fp->script->nfixed; } /* * Refresh and return fp->scopeChain. It may be stale if block scopes are * active but not yet reflected by objects in the scope chain. If a block * scope contains a with, eval, XML filtering predicate, or similar such * dynamically scoped construct, then compile-time block scope at fp->blocks * must reflect at runtime. */ extern JSObject * js_GetScopeChain(JSContext *cx, JSStackFrame *fp); /* * Given a context and a vector of [callee, this, args...] for a function that * was specified with a JSFUN_THISP_PRIMITIVE flag, get the primitive value of * |this| into *thisvp. In doing so, if |this| is an object, insist it is an * instance of clasp and extract its private slot value to return via *thisvp. * * NB: this function loads and uses *vp before storing *thisvp, so the two may * alias the same jsval. */ extern JSBool js_GetPrimitiveThis(JSContext *cx, jsval *vp, JSClass *clasp, jsval *thisvp); /* * For a call with arguments argv including argv[-1] (nominal |this|) and * argv[-2] (callee) replace null |this| with callee's parent and replace * primitive values with the equivalent wrapper objects. argv[-1] must not be * JSVAL_VOID or an activation object. */ extern JSObject * js_ComputeThis(JSContext *cx, jsval *argv); extern const uint16 js_PrimitiveTestFlags[]; #define PRIMITIVE_THIS_TEST(fun,thisv) \ (JS_ASSERT(!JSVAL_IS_VOID(thisv)), \ JSFUN_THISP_TEST(JSFUN_THISP_FLAGS((fun)->flags), \ js_PrimitiveTestFlags[JSVAL_TAG(thisv) - 1])) /* * The js::InvokeArgumentsGuard passed to js_Invoke must come from an * immediately-enclosing successful call to js::StackSpace::pushInvokeArgs, * i.e., there must have been no un-popped pushes to cx->stack(). Furthermore, * |args.getvp()[0]| should be the callee, |args.getvp()[1]| should be |this|, * and the range [args.getvp() + 2, args.getvp() + 2 + args.getArgc()) should * be initialized actual arguments. */ extern JS_REQUIRES_STACK JS_FRIEND_API(JSBool) js_Invoke(JSContext *cx, const js::InvokeArgsGuard &args, uintN flags); /* * Consolidated js_Invoke flags simply rename certain JSFRAME_* flags, so that * we can share bits stored in JSStackFrame.flags and passed to: * * js_Invoke * js_InternalInvoke * js_ValueToFunction * js_ValueToFunctionObject * js_ValueToCallableObject * js_ReportIsNotFunction * * See jsfun.h for the latter four and flag renaming macros. */ #define JSINVOKE_CONSTRUCT JSFRAME_CONSTRUCTING /* * Mask to isolate construct and iterator flags for use with jsfun.h functions. */ #define JSINVOKE_FUNFLAGS JSINVOKE_CONSTRUCT /* * "Internal" calls may come from C or C++ code using a JSContext on which no * JS is running (!cx->fp), so they may need to push a dummy JSStackFrame. */ #define js_InternalCall(cx,obj,fval,argc,argv,rval) \ js_InternalInvoke(cx, obj, fval, 0, argc, argv, rval) #define js_InternalConstruct(cx,obj,fval,argc,argv,rval) \ js_InternalInvoke(cx, obj, fval, JSINVOKE_CONSTRUCT, argc, argv, rval) extern JSBool js_InternalInvoke(JSContext *cx, JSObject *obj, jsval fval, uintN flags, uintN argc, jsval *argv, jsval *rval); extern JSBool js_InternalGetOrSet(JSContext *cx, JSObject *obj, jsid id, jsval fval, JSAccessMode mode, uintN argc, jsval *argv, jsval *rval); extern JS_FORCES_STACK JSBool js_Execute(JSContext *cx, JSObject *chain, JSScript *script, JSStackFrame *down, uintN flags, jsval *result); extern JS_REQUIRES_STACK JSBool js_InvokeConstructor(JSContext *cx, const js::InvokeArgsGuard &args, JSBool clampReturn); extern JS_REQUIRES_STACK JSBool js_Interpret(JSContext *cx); #define JSPROP_INITIALIZER 0x100 /* NB: Not a valid property attribute. */ extern JSBool js_CheckRedeclaration(JSContext *cx, JSObject *obj, jsid id, uintN attrs, JSObject **objp, JSProperty **propp); extern JSBool js_StrictlyEqual(JSContext *cx, jsval lval, jsval rval); /* === except that NaN is the same as NaN and -0 is not the same as +0. */ extern JSBool js_SameValue(jsval v1, jsval v2, JSContext *cx); extern JSBool js_InternNonIntElementId(JSContext *cx, JSObject *obj, jsval idval, jsid *idp); /* * Given an active context, a static scope level, and an upvar cookie, return * the value of the upvar. */ extern jsval& js_GetUpvar(JSContext *cx, uintN level, uintN cookie); /* * JS_LONE_INTERPRET indicates that the compiler should see just the code for * the js_Interpret function when compiling jsinterp.cpp. The rest of the code * from the file should be visible only when compiling jsinvoke.cpp. It allows * platform builds to optimize selectively js_Interpret when the granularity * of the optimizations with the given compiler is a compilation unit. * * JS_STATIC_INTERPRET is the modifier for functions defined in jsinterp.cpp * that only js_Interpret calls. When JS_LONE_INTERPRET is true all such * functions are declared below. */ #ifndef JS_LONE_INTERPRET # ifdef _MSC_VER # define JS_LONE_INTERPRET 0 # else # define JS_LONE_INTERPRET 1 # endif #endif #define JS_MAX_INLINE_CALL_COUNT 3000 #if !JS_LONE_INTERPRET # define JS_STATIC_INTERPRET static #else # define JS_STATIC_INTERPRET /* * ECMA requires "the global object", but in embeddings such as the browser, * which have multiple top-level objects (windows, frames, etc. in the DOM), * we prefer fun's parent. An example that causes this code to run: * * // in window w1 * function f() { return this } * function g() { return f } * * // in window w2 * var h = w1.g() * alert(h() == w1) * * The alert should display "true". */ extern JSObject * js_ComputeGlobalThis(JSContext *cx, jsval *argv); extern JS_REQUIRES_STACK JSBool js_EnterWith(JSContext *cx, jsint stackIndex); extern JS_REQUIRES_STACK void js_LeaveWith(JSContext *cx); extern JS_REQUIRES_STACK JSClass * js_IsActiveWithOrBlock(JSContext *cx, JSObject *obj, int stackDepth); /* * Unwind block and scope chains to match the given depth. The function sets * fp->sp on return to stackDepth. */ extern JS_REQUIRES_STACK JSBool js_UnwindScope(JSContext *cx, jsint stackDepth, JSBool normalUnwind); extern JSBool js_OnUnknownMethod(JSContext *cx, jsval *vp); /* * Find the results of incrementing or decrementing *vp. For pre-increments, * both *vp and *vp2 will contain the result on return. For post-increments, * vp will contain the original value converted to a number and vp2 will get * the result. Both vp and vp2 must be roots. */ extern JSBool js_DoIncDec(JSContext *cx, const JSCodeSpec *cs, jsval *vp, jsval *vp2); /* * Opcode tracing helper. When len is not 0, cx->fp->regs->pc[-len] gives the * previous opcode. */ extern JS_REQUIRES_STACK void js_TraceOpcode(JSContext *cx); /* * JS_OPMETER helper functions. */ extern void js_MeterOpcodePair(JSOp op1, JSOp op2); extern void js_MeterSlotOpcode(JSOp op, uint32 slot); #endif /* JS_LONE_INTERPRET */ JS_END_EXTERN_C inline JSObject * JSStackFrame::getThisObject(JSContext *cx) { return JSVAL_IS_PRIMITIVE(thisv) ? computeThisObject(cx) : JSVAL_TO_OBJECT(thisv); } #endif /* jsinterp_h___ */