gecko/js/src/jsfun.h

639 lines
22 KiB
C++

/* -*- 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 "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
*
* FUN_FLAT_CLOSURE implies FUN_INTERPRETED and u.i.script->upvarsOffset != 0.
* FUN_NULL_CLOSURE implies FUN_INTERPRETED and u.i.script->upvarsOffset == 0.
*
* FUN_INTERPRETED but not FUN_FLAT_CLOSURE 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, FUN_INTERPRETED 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 FUN_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 /* flag (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 */
#define FUN_OBJECT(fun) (static_cast<JSObject *>(fun))
#define FUN_KIND(fun) ((fun)->flags & JSFUN_KINDMASK)
#define FUN_SET_KIND(fun,k) ((fun)->flags = ((fun)->flags & ~JSFUN_KINDMASK) | (k))
#define FUN_INTERPRETED(fun) (FUN_KIND(fun) >= JSFUN_INTERPRETED)
#define FUN_FLAT_CLOSURE(fun)(FUN_KIND(fun) == JSFUN_FLAT_CLOSURE)
#define FUN_NULL_CLOSURE(fun)(FUN_KIND(fun) == JSFUN_NULL_CLOSURE)
#define FUN_SCRIPT(fun) (FUN_INTERPRETED(fun) ? (fun)->u.i.script : NULL)
#define FUN_CLASP(fun) (JS_ASSERT(!FUN_INTERPRETED(fun)), \
fun->u.n.clasp)
#define FUN_TRCINFO(fun) (JS_ASSERT(!FUN_INTERPRETED(fun)), \
JS_ASSERT((fun)->flags & JSFUN_TRCINFO), \
fun->u.n.trcinfo)
/*
* Formal parameters, local variables, and upvars are stored in a shape tree
* path with its latest node at fun->u.i.names. The addLocal, lookupLocal, and
* getLocalNameArray methods abstract away this detail.
*
* The lastArg, lastVar, and lastUpvar JSFunction methods provide more direct
* access to the shape path. These methods may be used to make a Shape::Range
* for iterating over the relevant shapes from youngest to oldest (i.e., last
* or right-most to first or left-most in source order).
*
* Sometimes iteration order must be from oldest to youngest, however. For such
* cases, use getLocalNameArray. The RAII helper class js::AutoLocalNameArray,
* defined in jscntxt.h, should be used where possible instead of direct calls
* to getLocalNameArray.
*/
enum JSLocalKind {
JSLOCAL_NONE,
JSLOCAL_ARG,
JSLOCAL_VAR,
JSLOCAL_CONST,
JSLOCAL_UPVAR
};
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 {
uint16 nvars; /* number of local variables */
uint16 nupvars; /* number of upvars (computable from script
but here for faster access) */
uint16 skipmin; /* net skip amount up (toward zero) from
script->staticLevel to nearest upvar,
including upvars in nested functions */
JSPackedBool wrapper; /* true if this function is a wrapper that
rewrites bytecode optimized for a function
judged non-escaping by the compiler, which
then escaped via the debugger or a rogue
indirect eval; if true, then this function
object's proto is the wrapped object */
JSScript *script; /* interpreted bytecode descriptor or null */
js::Shape *names; /* argument and variable names */
} i;
} u;
JSAtom *atom; /* name for diagnostics and decompiling */
bool optimizedClosure() const { return FUN_KIND(this) > JSFUN_INTERPRETED; }
bool needsWrapper() const { return FUN_NULL_CLOSURE(this) && u.i.skipmin != 0; }
bool isInterpreted() const { return FUN_INTERPRETED(this); }
bool isNative() const { return !FUN_INTERPRETED(this); }
bool isConstructor() const { return flags & JSFUN_CONSTRUCTOR; }
bool isHeavyweight() const { return JSFUN_HEAVYWEIGHT_TEST(flags); }
bool isFunctionPrototype() const { return flags & JSFUN_PROTOTYPE; }
inline bool inStrictMode() const;
bool acceptsPrimitiveThis() const { return flags & JSFUN_PRIMITIVE_THIS; }
uintN countVars() const {
JS_ASSERT(FUN_INTERPRETED(this));
return u.i.nvars;
}
/* uint16 representation bounds number of call object dynamic slots. */
enum { MAX_ARGS_AND_VARS = 2 * ((1U << 16) - 1) };
uintN countArgsAndVars() const {
JS_ASSERT(FUN_INTERPRETED(this));
return nargs + u.i.nvars;
}
uintN countLocalNames() const {
JS_ASSERT(FUN_INTERPRETED(this));
return countArgsAndVars() + u.i.nupvars;
}
bool hasLocalNames() const {
JS_ASSERT(FUN_INTERPRETED(this));
return countLocalNames() != 0;
}
int sharpSlotBase(JSContext *cx);
uint32 countUpvarSlots() const;
const js::Shape *lastArg() const;
const js::Shape *lastVar() const;
const js::Shape *lastUpvar() const { return u.i.names; }
bool addLocal(JSContext *cx, JSAtom *atom, JSLocalKind kind);
/*
* Look up an argument or variable name returning its kind when found or
* JSLOCAL_NONE when no such name exists. When indexp is not null and the
* name exists, *indexp will receive the index of the corresponding
* argument or variable.
*/
JSLocalKind lookupLocal(JSContext *cx, JSAtom *atom, uintN *indexp);
/*
* Function and macros to work with local names as an array of words.
* getLocalNameArray returns the array, or null if we are out of memory.
* This function must be called only when fun->hasLocalNames().
*
* The supplied pool is used to allocate the returned array, so the caller
* is obligated to mark and release to free it.
*
* The elements of the array with index less than fun->nargs correspond to
* the names of function formal parameters. An index >= fun->nargs
* addresses a var binding. Use JS_LOCAL_NAME_TO_ATOM to convert array's
* element to an atom pointer. This pointer can be null when the element is
* for a formal parameter corresponding to a destructuring pattern.
*
* If nameWord does not name a formal parameter, use JS_LOCAL_NAME_IS_CONST
* to check if nameWord corresponds to the const declaration.
*/
jsuword *getLocalNameArray(JSContext *cx, struct JSArenaPool *pool);
void freezeLocalNames(JSContext *cx);
/*
* If fun's formal parameters include any duplicate names, return one
* of them (chosen arbitrarily). If they are all unique, return NULL.
*/
JSAtom *findDuplicateFormal() const;
#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 FUN_INTERPRETED(this) && (FUN_FLAT_CLOSURE(this) || u.i.nupvars == 0);
}
bool joinable() const {
return flags & JSFUN_JOINABLE;
}
JSObject &compiledFunObj() {
return *this;
}
private:
/*
* js_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:
void setJoinable() {
JS_ASSERT(FUN_INTERPRETED(this));
getSlotRef(METHOD_ATOM_SLOT).setNull();
flags |= JSFUN_JOINABLE;
}
/*
* 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())
? STRING_TO_ATOM(getSlot(METHOD_ATOM_SLOT).toString())
: NULL;
}
void setMethodAtom(JSAtom *atom) {
JS_ASSERT(joinable());
getSlotRef(METHOD_ATOM_SLOT).setString(ATOM_TO_STRING(atom));
}
js::Native maybeNative() const {
return isInterpreted() ? NULL : u.n.native;
}
JSScript *script() const {
JS_ASSERT(isInterpreted());
return u.i.script;
}
/* Number of extra fixed function object slots. */
static const uint32 CLASS_RESERVED_SLOTS = JSObject::FUN_CLASS_RESERVED_SLOTS;
};
/*
* 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
/*
* NB: the Arguments classes are uninitialized internal classes that masquerade
* (according to Object.prototype.toString.call(arguments)) as "Arguments",
* while having Object.getPrototypeOf(arguments) === Object.prototype.
*
* WARNING (to alert embedders reading this private .h file): arguments objects
* are *not* thread-safe and should not be used concurrently -- they should be
* used by only one thread at a time, preferably by only one thread over their
* lifetime (a JS worker that migrates from one OS thread to another but shares
* nothing is ok).
*
* Yes, this is an incompatible change, which prefigures the impending move to
* single-threaded objects and GC heaps.
*/
extern js::Class js_ArgumentsClass;
namespace js {
extern Class StrictArgumentsClass;
struct ArgumentsData {
js::Value callee;
js::Value slots[1];
};
}
inline bool
JSObject::isNormalArguments() const
{
return getClass() == &js_ArgumentsClass;
}
inline bool
JSObject::isStrictArguments() const
{
return getClass() == &js::StrictArgumentsClass;
}
inline bool
JSObject::isArguments() const
{
return isNormalArguments() || isStrictArguments();
}
#define JS_ARGUMENTS_OBJECT_ON_TRACE ((void *)0xa126)
extern JS_PUBLIC_DATA(js::Class) js_CallClass;
extern JS_PUBLIC_DATA(js::Class) js_FunctionClass;
extern js::Class js_DeclEnvClass;
inline bool
JSObject::isCall() const
{
return getClass() == &js_CallClass;
}
inline bool
JSObject::isFunction() const
{
return getClass() == &js_FunctionClass;
}
inline JSFunction *
JSObject::getFunctionPrivate() const
{
JS_ASSERT(isFunction());
return reinterpret_cast<JSFunction *>(getPrivate());
}
namespace js {
/*
* NB: jsapi.h and jsobj.h must be included before any call to this macro.
*/
#define VALUE_IS_FUNCTION(cx, v) \
(!JSVAL_IS_PRIMITIVE(v) && JSVAL_TO_OBJECT(v)->isFunction())
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, JSFunction **fun)
{
JSObject *funobj;
bool b = IsFunctionObject(v, &funobj);
if (b)
*fun = funobj->getFunctionPrivate();
return b;
}
/*
* Macro to access the private slot of the function object after the slot is
* initialized.
*/
#define GET_FUNCTION_PRIVATE(cx, funobj) \
(JS_ASSERT((funobj)->isFunction()), \
(JSFunction *) (funobj)->getPrivate())
/*
* 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;
}
} /* namespace js */
extern JSString *
fun_toStringHelper(JSContext *cx, JSObject *obj, uintN indent);
extern JSFunction *
js_NewFunction(JSContext *cx, JSObject *funobj, js::Native native, uintN nargs,
uintN flags, JSObject *parent, JSAtom *atom);
extern JSObject *
js_InitFunctionClass(JSContext *cx, JSObject *obj);
extern JSObject *
js_InitArgumentsClass(JSContext *cx, JSObject *obj);
extern void
js_TraceFunction(JSTracer *trc, JSFunction *fun);
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)
{
JS_ASSERT(parent);
JSObject *proto;
if (!js_GetClassPrototype(cx, parent, JSProto_Function, &proto))
return NULL;
return js_CloneFunctionObject(cx, fun, parent, proto);
}
extern JSObject * JS_FASTCALL
js_AllocFlatClosure(JSContext *cx, JSFunction *fun, JSObject *scopeChain);
extern JS_REQUIRES_STACK JSObject *
js_NewFlatClosure(JSContext *cx, JSFunction *fun, JSOp op, size_t oplen);
extern JS_REQUIRES_STACK JSObject *
js_NewDebuggableFlatClosure(JSContext *cx, JSFunction *fun);
extern JSFunction *
js_DefineFunction(JSContext *cx, JSObject *obj, JSAtom *atom, js::Native native,
uintN nargs, uintN flags);
/*
* Flags for js_ValueToFunction and js_ReportIsNotFunction. We depend on the
* fact that JSINVOKE_CONSTRUCT (aka JSFRAME_CONSTRUCTING) is 1, and test that
* with #if/#error in jsfun.c.
*/
#define JSV2F_CONSTRUCT JSINVOKE_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_GetCallObject(JSContext *cx, JSStackFrame *fp);
extern JSObject * JS_FASTCALL
js_CreateCallObjectOnTrace(JSContext *cx, JSFunction *fun, JSObject *callee, JSObject *scopeChain);
extern void
js_PutCallObject(JSContext *cx, JSStackFrame *fp);
extern JSBool JS_FASTCALL
js_PutCallObjectOnTrace(JSContext *cx, JSObject *scopeChain, uint32 nargs,
js::Value *argv, uint32 nvars, js::Value *slots);
extern JSBool
js_GetCallArg(JSContext *cx, JSObject *obj, jsid id, js::Value *vp);
extern JSBool
js_GetCallVar(JSContext *cx, JSObject *obj, jsid id, js::Value *vp);
extern JSBool
SetCallArg(JSContext *cx, JSObject *obj, jsid id, js::Value *vp);
extern JSBool
SetCallVar(JSContext *cx, JSObject *obj, jsid id, js::Value *vp);
/*
* Slower version of js_GetCallVar used when call_resolve detects an attempt to
* leak an optimized closure via indirect or debugger eval.
*/
extern JSBool
js_GetCallVarChecked(JSContext *cx, JSObject *obj, jsid id, js::Value *vp);
extern JSBool
js_GetArgsValue(JSContext *cx, JSStackFrame *fp, js::Value *vp);
extern JSBool
js_GetArgsProperty(JSContext *cx, JSStackFrame *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, JSStackFrame *fp);
extern void
js_PutArgsObject(JSContext *cx, JSStackFrame *fp);
inline bool
js_IsNamedLambda(JSFunction *fun) { return (fun->flags & JSFUN_LAMBDA) && fun->atom; }
/*
* Maximum supported value of arguments.length. It bounds the maximum number of
* arguments that can be supplied via the second (so-called |argArray|) param
* to Function.prototype.apply. This value also bounds the number of elements
* parsed in an array initialiser.
*
* The thread's stack is the limiting factor for this number. It is currently
* 2MB, which fits a little less than 2^19 arguments (once the stack frame,
* callstack, etc. are included). Pick a max args length that is a little less.
*/
const uint32 JS_ARGS_LENGTH_MAX = JS_BIT(19) - 1024;
/*
* JSSLOT_ARGS_LENGTH stores ((argc << 1) | overwritten_flag) as an Int32
* Value. Thus (JS_ARGS_LENGTH_MAX << 1) | 1 must be less than JSVAL_INT_MAX.
*/
JS_STATIC_ASSERT(JS_ARGS_LENGTH_MAX <= JS_BIT(30));
JS_STATIC_ASSERT(((JS_ARGS_LENGTH_MAX << 1) | 1) <= JSVAL_INT_MAX);
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___ */