gecko/js/src/jsinterp.h

463 lines
16 KiB
C++

/* -*- 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_COMPUTED_THIS = 0x02, /* frame.thisv was computed already and
JSVAL_IS_OBJECT(thisv) */
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_OVERRIDE_ARGS = 0x100, /* overridden arguments local variable */
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 */
jsval thisv; /* "this" pointer if in method */
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;
}
};
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, replace
* primitive values with the equivalent wrapper objects and censor activation
* objects as, per ECMA-262, they may not be referred to by |this|. argv[-1]
* must not be a JSVAL_VOID.
*/
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)
{
if (flags & JSFRAME_COMPUTED_THIS)
return JSVAL_TO_OBJECT(thisv); /* JSVAL_COMPUTED_THIS invariant */
JSObject* obj = js_ComputeThis(cx, argv);
if (!obj)
return NULL;
thisv = OBJECT_TO_JSVAL(obj);
flags |= JSFRAME_COMPUTED_THIS;
return obj;
}
#endif /* jsinterp_h___ */