jsfun.h
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* ***** 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 jsfun_h___
#define jsfun_h___
/*
* JS function definitions.
*/
#include "jsprvtd.h"
#include "jspubtd.h"
#include "jsobj.h"
#include "jsatom.h"
#include "jsscript.h"
#include "jsstr.h"
#include "jsopcode.h"
/*
* The high two bits of JSFunction.flags encode whether the function is native
* or interpreted, and if interpreted, what kind of optimized closure form (if
* any) it might be.
*
* 00 not interpreted
* 01 interpreted, neither flat nor null closure
* 10 interpreted, flat closure
* 11 interpreted, null closure
*
* isFlatClosure() implies isInterpreted() and u.i.script->upvarsOffset != 0.
* isNullClosure() implies isInterpreted() and u.i.script->upvarsOffset == 0.
*
* isInterpreted() but not isFlatClosure() and u.i.script->upvarsOffset != 0
* is an Algol-like function expression or nested function, i.e., a function
* that never escapes upward or downward (heapward), and is only ever called.
*
* Finally, isInterpreted() and u.i.script->upvarsOffset == 0 could be either
* a non-closure (a global function definition, or any function that uses no
* outer names), or a closure of an escaping function that uses outer names
* whose values can't be snapshot (because the outer names could be reassigned
* after the closure is formed, or because assignments could not be analyzed
* due to with or eval).
*
* Such a hard-case function must use JSOP_NAME, etc., and reify outer function
* activations' call objects, etc. if it's not a global function.
*
* NB: JSFUN_EXPR_CLOSURE reuses JSFUN_STUB_GSOPS, which is an API request flag
* bit only, never stored in fun->flags.
*
* If we need more bits in the future, all flags for interpreted functions can
* move to u.i.script->flags. For now we use function flag bits to minimize
* pointer-chasing.
*/
#define JSFUN_JOINABLE 0x0001 /* function is null closure that does not
appear to call itself via its own name
or arguments.callee */
#define JSFUN_PROTOTYPE 0x0800 /* function is Function.prototype for some
global object */
#define JSFUN_EXPR_CLOSURE 0x1000 /* expression closure: function(x) x*x */
#define JSFUN_TRCINFO 0x2000 /* when set, u.n.trcinfo is non-null,
JSFunctionSpec::call points to a
JSNativeTraceInfo. */
#define JSFUN_INTERPRETED 0x4000 /* use u.i if kind >= this value else u.n */
#define JSFUN_FLAT_CLOSURE 0x8000 /* flat (aka "display") closure */
#define JSFUN_NULL_CLOSURE 0xc000 /* null closure entrains no scope chain */
#define JSFUN_KINDMASK 0xc000 /* encode interp vs. native and closure
optimization level -- see above */
struct JSFunction : public JSObject_Slots2
{
/* Functions always have two fixed slots (FUN_CLASS_RESERVED_SLOTS). */
uint16 nargs; /* maximum number of specified arguments,
reflected as f.length/f.arity */
uint16 flags; /* flags, see JSFUN_* below and in jsapi.h */
union U {
struct {
js::Native native; /* native method pointer or null */
js::Class *clasp; /* class of objects constructed
by this function */
JSNativeTraceInfo *trcinfo;
} n;
struct Scripted {
JSScript *script; /* interpreted bytecode descriptor or null */
uint16 skipmin; /* net skip amount up (toward zero) from
script->staticLevel to nearest upvar,
including upvars in nested functions */
js::Shape *names; /* argument and variable names */
} i;
void *nativeOrScript;
} u;
JSAtom *atom; /* name for diagnostics and decompiling */
bool optimizedClosure() const { return kind() > JSFUN_INTERPRETED; }
bool isInterpreted() const { return kind() >= JSFUN_INTERPRETED; }
bool isNative() const { return !isInterpreted(); }
bool isConstructor() const { return flags & JSFUN_CONSTRUCTOR; }
bool isHeavyweight() const { return JSFUN_HEAVYWEIGHT_TEST(flags); }
bool isNullClosure() const { return kind() == JSFUN_NULL_CLOSURE; }
bool isFlatClosure() const { return kind() == JSFUN_FLAT_CLOSURE; }
bool isFunctionPrototype() const { return flags & JSFUN_PROTOTYPE; }
bool isInterpretedConstructor() const { return isInterpreted() && !isFunctionPrototype(); }
uint16 kind() const { return flags & JSFUN_KINDMASK; }
void setKind(uint16 k) {
JS_ASSERT(!(k & ~JSFUN_KINDMASK));
flags = (flags & ~JSFUN_KINDMASK) | k;
}
/* Returns the strictness of this function, which must be interpreted. */
inline bool inStrictMode() const;
void setArgCount(uint16 nargs) {
JS_ASSERT(this->nargs == 0);
this->nargs = nargs;
}
/* uint16 representation bounds number of call object dynamic slots. */
enum { MAX_ARGS_AND_VARS = 2 * ((1U << 16) - 1) };
#define JS_LOCAL_NAME_TO_ATOM(nameWord) ((JSAtom *) ((nameWord) & ~(jsuword) 1))
#define JS_LOCAL_NAME_IS_CONST(nameWord) ((((nameWord) & (jsuword) 1)) != 0)
bool mightEscape() const {
return isInterpreted() && (isFlatClosure() || !script()->bindings.hasUpvars());
}
bool joinable() const {
return flags & JSFUN_JOINABLE;
}
JSObject &compiledFunObj() {
return *this;
}
private:
/*
* FunctionClass reserves two slots, which are free in JSObject::fslots
* without requiring dslots allocation. Null closures that can be joined to
* a compiler-created function object use the first one to hold a mutable
* methodAtom() state variable, needed for correct foo.caller handling.
*/
enum {
METHOD_ATOM_SLOT = JSSLOT_FUN_METHOD_ATOM
};
public:
inline void setJoinable();
/*
* Method name imputed from property uniquely assigned to or initialized,
* where the function does not need to be cloned to carry a scope chain or
* flattened upvars.
*/
JSAtom *methodAtom() const {
return (joinable() && getSlot(METHOD_ATOM_SLOT).isString())
? &getSlot(METHOD_ATOM_SLOT).toString()->asAtom()
: NULL;
}
inline void setMethodAtom(JSAtom *atom);
JSScript *script() const {
JS_ASSERT(isInterpreted());
return u.i.script;
}
JSScript * maybeScript() const {
return isInterpreted() ? script() : NULL;
}
JSNative native() const {
JS_ASSERT(isNative());
return u.n.native;
}
JSNative maybeNative() const {
return isInterpreted() ? NULL : native();
}
static uintN offsetOfNativeOrScript() {
JS_STATIC_ASSERT(offsetof(U, n.native) == offsetof(U, i.script));
JS_STATIC_ASSERT(offsetof(U, n.native) == offsetof(U, nativeOrScript));
return offsetof(JSFunction, u.nativeOrScript);
}
/* Number of extra fixed function object slots. */
static const uint32 CLASS_RESERVED_SLOTS = JSObject::FUN_CLASS_RESERVED_SLOTS;
js::Class *getConstructorClass() const {
JS_ASSERT(isNative());
return u.n.clasp;
}
void setConstructorClass(js::Class *clasp) {
JS_ASSERT(isNative());
u.n.clasp = clasp;
}
JSNativeTraceInfo *getTraceInfo() const {
JS_ASSERT(isNative());
JS_ASSERT(flags & JSFUN_TRCINFO);
return u.n.trcinfo;
}
};
/*
* Trace-annotated native. This expands to a JSFunctionSpec initializer (like
* JS_FN in jsapi.h). fastcall is a FastNative; trcinfo is a
* JSNativeTraceInfo*.
*/
#ifdef JS_TRACER
/* MSVC demands the intermediate (void *) cast here. */
# define JS_TN(name,fastcall,nargs,flags,trcinfo) \
JS_FN(name, JS_DATA_TO_FUNC_PTR(Native, trcinfo), nargs, \
(flags) | JSFUN_STUB_GSOPS | JSFUN_TRCINFO)
#else
# define JS_TN(name,fastcall,nargs,flags,trcinfo) \
JS_FN(name, fastcall, nargs, flags)
#endif
inline JSFunction *
JSObject::getFunctionPrivate() const
{
JS_ASSERT(isFunction());
return reinterpret_cast<JSFunction *>(getPrivate());
}
namespace js {
static JS_ALWAYS_INLINE bool
IsFunctionObject(const js::Value &v)
{
return v.isObject() && v.toObject().isFunction();
}
static JS_ALWAYS_INLINE bool
IsFunctionObject(const js::Value &v, JSObject **funobj)
{
return v.isObject() && (*funobj = &v.toObject())->isFunction();
}
static JS_ALWAYS_INLINE bool
IsFunctionObject(const js::Value &v, JSObject **funobj, JSFunction **fun)
{
bool b = IsFunctionObject(v, funobj);
if (b)
*fun = (*funobj)->getFunctionPrivate();
return b;
}
static JS_ALWAYS_INLINE bool
IsFunctionObject(const js::Value &v, JSFunction **fun)
{
JSObject *funobj;
return IsFunctionObject(v, &funobj, fun);
}
static JS_ALWAYS_INLINE bool
IsNativeFunction(const js::Value &v)
{
JSFunction *fun;
return IsFunctionObject(v, &fun) && fun->isNative();
}
static JS_ALWAYS_INLINE bool
IsNativeFunction(const js::Value &v, JSFunction **fun)
{
return IsFunctionObject(v, fun) && (*fun)->isNative();
}
static JS_ALWAYS_INLINE bool
IsNativeFunction(const js::Value &v, JSNative native)
{
JSFunction *fun;
return IsFunctionObject(v, &fun) && fun->maybeNative() == native;
}
/*
* When we have an object of a builtin class, we don't quite know what its
* valueOf/toString methods are, since these methods may have been overwritten
* or shadowed. However, we can still do better than the general case by
* hard-coding the necessary properties for us to find the native we expect.
*
* TODO: a per-thread shape-based cache would be faster and simpler.
*/
static JS_ALWAYS_INLINE bool
ClassMethodIsNative(JSContext *cx, JSObject *obj, Class *clasp, jsid methodid, JSNative native)
{
JS_ASSERT(obj->getClass() == clasp);
Value v;
if (!HasDataProperty(cx, obj, methodid, &v)) {
JSObject *proto = obj->getProto();
if (!proto || proto->getClass() != clasp || !HasDataProperty(cx, proto, methodid, &v))
return false;
}
return js::IsNativeFunction(v, native);
}
extern JS_ALWAYS_INLINE bool
SameTraceType(const Value &lhs, const Value &rhs)
{
return SameType(lhs, rhs) &&
(lhs.isPrimitive() ||
lhs.toObject().isFunction() == rhs.toObject().isFunction());
}
/*
* Return true if this is a compiler-created internal function accessed by
* its own object. Such a function object must not be accessible to script
* or embedding code.
*/
inline bool
IsInternalFunctionObject(JSObject *funobj)
{
JS_ASSERT(funobj->isFunction());
JSFunction *fun = (JSFunction *) funobj->getPrivate();
return funobj == fun && (fun->flags & JSFUN_LAMBDA) && !funobj->getParent();
}
/* Valueified JS_IsConstructing. */
static JS_ALWAYS_INLINE bool
IsConstructing(const Value *vp)
{
#ifdef DEBUG
JSObject *callee = &JS_CALLEE(cx, vp).toObject();
if (callee->isFunction()) {
JSFunction *fun = callee->getFunctionPrivate();
JS_ASSERT((fun->flags & JSFUN_CONSTRUCTOR) != 0);
} else {
JS_ASSERT(callee->getClass()->construct != NULL);
}
#endif
return vp[1].isMagic();
}
static JS_ALWAYS_INLINE bool
IsConstructing_PossiblyWithGivenThisObject(const Value *vp, JSObject **ctorThis)
{
#ifdef DEBUG
JSObject *callee = &JS_CALLEE(cx, vp).toObject();
if (callee->isFunction()) {
JSFunction *fun = callee->getFunctionPrivate();
JS_ASSERT((fun->flags & JSFUN_CONSTRUCTOR) != 0);
} else {
JS_ASSERT(callee->getClass()->construct != NULL);
}
#endif
bool isCtor = vp[1].isMagic();
if (isCtor)
*ctorThis = vp[1].getMagicObjectOrNullPayload();
return isCtor;
}
inline const char *
GetFunctionNameBytes(JSContext *cx, JSFunction *fun, JSAutoByteString *bytes)
{
if (fun->atom)
return bytes->encode(cx, fun->atom);
return js_anonymous_str;
}
extern JSFunctionSpec function_methods[];
extern JSBool
Function(JSContext *cx, uintN argc, Value *vp);
extern bool
IsBuiltinFunctionConstructor(JSFunction *fun);
/*
* Preconditions: funobj->isInterpreted() && !funobj->isFunctionPrototype() &&
* !funobj->isBoundFunction(). This is sufficient to establish that funobj has
* a non-configurable non-method .prototype data property, thought it might not
* have been resolved yet, and its value could be anything.
*
* Return the shape of the .prototype property of funobj, resolving it if
* needed. On error, return NULL.
*
* This is not safe to call on trace because it defines properties, which can
* trigger lookups that could reenter.
*/
const Shape *
LookupInterpretedFunctionPrototype(JSContext *cx, JSObject *funobj);
} /* namespace js */
extern JSString *
fun_toStringHelper(JSContext *cx, JSObject *obj, uintN indent);
extern JSFunction *
js_NewFunction(JSContext *cx, JSObject *funobj, JSNative native, uintN nargs,
uintN flags, JSObject *parent, JSAtom *atom);
extern void
js_FinalizeFunction(JSContext *cx, JSFunction *fun);
extern JSObject * JS_FASTCALL
js_CloneFunctionObject(JSContext *cx, JSFunction *fun, JSObject *parent,
JSObject *proto);
inline JSObject *
CloneFunctionObject(JSContext *cx, JSFunction *fun, JSObject *parent,
bool ignoreSingletonClone = false)
{
JS_ASSERT(parent);
JSObject *proto;
if (!js_GetClassPrototype(cx, parent, JSProto_Function, &proto))
return NULL;
/*
* For attempts to clone functions at a function definition opcode or from
* a method barrier, don't perform the clone if the function has singleton
* type. CloneFunctionObject was called pessimistically, and we need to
* preserve the type's property that if it is singleton there is only a
* single object with its type in existence.
*/
if (ignoreSingletonClone && fun->hasSingletonType()) {
JS_ASSERT(fun->getProto() == proto);
fun->setParent(parent);
return fun;
}
return js_CloneFunctionObject(cx, fun, parent, proto);
}
inline JSObject *
CloneFunctionObject(JSContext *cx, JSFunction *fun)
{
/*
* Variant which makes an exact clone of fun, preserving parent and proto.
* Calling the above version CloneFunctionObject(cx, fun, fun->getParent())
* is not equivalent: API clients, including XPConnect, can reparent
* objects so that fun->getGlobal() != fun->getProto()->getGlobal().
* See ReparentWrapperIfFound.
*/
JS_ASSERT(fun->getParent() && fun->getProto());
if (fun->hasSingletonType())
return fun;
return js_CloneFunctionObject(cx, fun, fun->getParent(), fun->getProto());
}
extern JSObject * JS_FASTCALL
js_AllocFlatClosure(JSContext *cx, JSFunction *fun, JSObject *scopeChain);
extern JSObject *
js_NewFlatClosure(JSContext *cx, JSFunction *fun, JSOp op, size_t oplen);
extern JSFunction *
js_DefineFunction(JSContext *cx, JSObject *obj, jsid id, JSNative native,
uintN nargs, uintN flags);
/*
* Flags for js_ValueToFunction and js_ReportIsNotFunction.
*/
#define JSV2F_CONSTRUCT INITIAL_CONSTRUCT
#define JSV2F_SEARCH_STACK 0x10000
extern JSFunction *
js_ValueToFunction(JSContext *cx, const js::Value *vp, uintN flags);
extern JSObject *
js_ValueToFunctionObject(JSContext *cx, js::Value *vp, uintN flags);
extern JSObject *
js_ValueToCallableObject(JSContext *cx, js::Value *vp, uintN flags);
extern void
js_ReportIsNotFunction(JSContext *cx, const js::Value *vp, uintN flags);
extern JSObject * JS_FASTCALL
js_CreateCallObjectOnTrace(JSContext *cx, JSFunction *fun, JSObject *callee, JSObject *scopeChain);
extern void
js_PutCallObject(js::StackFrame *fp);
extern JSBool JS_FASTCALL
js_PutCallObjectOnTrace(JSObject *scopeChain, uint32 nargs, js::Value *argv,
uint32 nvars, js::Value *slots);
namespace js {
CallObject *
CreateFunCallObject(JSContext *cx, StackFrame *fp);
CallObject *
CreateEvalCallObject(JSContext *cx, StackFrame *fp);
extern JSBool
GetCallArg(JSContext *cx, JSObject *obj, jsid id, js::Value *vp);
extern JSBool
GetCallVar(JSContext *cx, JSObject *obj, jsid id, js::Value *vp);
extern JSBool
GetCallUpvar(JSContext *cx, JSObject *obj, jsid id, js::Value *vp);
extern JSBool
SetCallArg(JSContext *cx, JSObject *obj, jsid id, JSBool strict, js::Value *vp);
extern JSBool
SetCallVar(JSContext *cx, JSObject *obj, jsid id, JSBool strict, js::Value *vp);
extern JSBool
SetCallUpvar(JSContext *cx, JSObject *obj, jsid id, JSBool strict, js::Value *vp);
} // namespace js
extern JSBool
js_GetArgsValue(JSContext *cx, js::StackFrame *fp, js::Value *vp);
extern JSBool
js_GetArgsProperty(JSContext *cx, js::StackFrame *fp, jsid id, js::Value *vp);
/*
* Get the arguments object for the given frame. If the frame is strict mode
* code, its current arguments will be copied into the arguments object.
*
* NB: Callers *must* get the arguments object before any parameters are
* mutated when the frame is strict mode code! The emitter ensures this
* occurs for strict mode functions containing syntax which might mutate a
* named parameter by synthesizing an arguments access at the start of the
* function.
*/
extern JSObject *
js_GetArgsObject(JSContext *cx, js::StackFrame *fp);
extern void
js_PutArgsObject(js::StackFrame *fp);
inline bool
js_IsNamedLambda(JSFunction *fun) { return (fun->flags & JSFUN_LAMBDA) && fun->atom; }
extern JSBool
js_XDRFunctionObject(JSXDRState *xdr, JSObject **objp);
extern JSBool
js_fun_apply(JSContext *cx, uintN argc, js::Value *vp);
extern JSBool
js_fun_call(JSContext *cx, uintN argc, js::Value *vp);
#endif /* jsfun_h___ */