1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
2  *
3  * ***** BEGIN LICENSE BLOCK *****
4  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
5  *
6  * The contents of this file are subject to the Mozilla Public License Version
7  * 1.1 (the "License"); you may not use this file except in compliance with
8  * the License. You may obtain a copy of the License at
9  * http://www.mozilla.org/MPL/
10  *
11  * Software distributed under the License is distributed on an "AS IS" basis,
12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13  * for the specific language governing rights and limitations under the
14  * License.
15  *
16  * The Original Code is Mozilla Communicator client code, released
17  * March 31, 1998.
18  *
19  * The Initial Developer of the Original Code is
20  * Netscape Communications Corporation.
21  * Portions created by the Initial Developer are Copyright (C) 1998
22  * the Initial Developer. All Rights Reserved.
23  *
24  * Contributor(s):
25  *
26  * Alternatively, the contents of this file may be used under the terms of
27  * either of the GNU General Public License Version 2 or later (the "GPL"),
28  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
29  * in which case the provisions of the GPL or the LGPL are applicable instead
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33  * decision by deleting the provisions above and replace them with the notice
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35  * the provisions above, a recipient may use your version of this file under
36  * the terms of any one of the MPL, the GPL or the LGPL.
37  *
38  * ***** END LICENSE BLOCK ***** */
39 
40 #ifndef jsinterp_h___
41 #define jsinterp_h___
42 /*
43  * JS interpreter interface.
44  */
45 #include "jsprvtd.h"
46 #include "jspubtd.h"
47 
48 JS_BEGIN_EXTERN_C
49 
50 /*
51  * JS stack frame, may be allocated on the C stack by native callers.  Always
52  * allocated on cx->stackPool for calls from the interpreter to an interpreted
53  * function.
54  *
55  * NB: This struct is manually initialized in jsinterp.c and jsiter.c.  If you
56  * add new members, update both files.  But first, try to remove members.  The
57  * sharp* and xml* members should be moved onto the stack as local variables
58  * with well-known slots, if possible.
59  */
60 struct JSStackFrame {
61     JSObject        *callobj;       /* lazily created Call object */
62     JSObject        *argsobj;       /* lazily created arguments object */
63     JSObject        *varobj;        /* variables object, where vars go */
64     JSScript        *script;        /* script being interpreted */
65     JSFunction      *fun;           /* function being called or null */
66     JSObject        *thisp;         /* "this" pointer if in method */
67     uintN           argc;           /* actual argument count */
68     jsval           *argv;          /* base of argument stack slots */
69     jsval           rval;           /* function return value */
70     uintN           nvars;          /* local variable count */
71     jsval           *vars;          /* base of variable stack slots */
72     JSStackFrame    *down;          /* previous frame */
73     void            *annotation;    /* used by Java security */
74     JSObject        *scopeChain;    /* scope chain */
75     jsbytecode      *pc;            /* program counter */
76     jsval           *sp;            /* stack pointer */
77     jsval           *spbase;        /* operand stack base */
78     uintN           sharpDepth;     /* array/object initializer depth */
79     JSObject        *sharpArray;    /* scope for #n= initializer vars */
80     uint32          flags;          /* frame flags -- see below */
81     JSStackFrame    *dormantNext;   /* next dormant frame chain */
82     JSObject        *xmlNamespace;  /* null or default xml namespace in E4X */
83     JSObject        *blockChain;    /* active compile-time block scopes */
84 };
85 
86 typedef struct JSInlineFrame {
87     JSStackFrame    frame;          /* base struct */
88     jsval           *rvp;           /* ptr to caller's return value slot */
89     void            *mark;          /* mark before inline frame */
90     void            *hookData;      /* debugger call hook data */
91     JSVersion       callerVersion;  /* dynamic version of calling script */
92 } JSInlineFrame;
93 
94 /* JS stack frame flags. */
95 #define JSFRAME_CONSTRUCTING  0x01  /* frame is for a constructor invocation */
96 #define JSFRAME_INTERNAL      0x02  /* internal call, not invoked by a script */
97 #define JSFRAME_SKIP_CALLER   0x04  /* skip one link when evaluating f.caller
98                                        for this invocation of f */
99 #define JSFRAME_ASSIGNING     0x08  /* a complex (not simplex JOF_ASSIGNING) op
100                                        is currently assigning to a property */
101 #define JSFRAME_DEBUGGER      0x10  /* frame for JS_EvaluateInStackFrame */
102 #define JSFRAME_EVAL          0x20  /* frame for obj_eval */
103 #define JSFRAME_SPECIAL       0x30  /* special evaluation frame flags */
104 #define JSFRAME_COMPILING     0x40  /* frame is being used by compiler */
105 #define JSFRAME_COMPILE_N_GO  0x80  /* compiler-and-go mode, can optimize name
106                                        references based on scope chain */
107 #define JSFRAME_SCRIPT_OBJECT 0x100 /* compiling source for a Script object */
108 #define JSFRAME_YIELDING      0x200 /* js_Interpret dispatched JSOP_YIELD */
109 #define JSFRAME_FILTERING     0x400 /* XML filtering predicate expression */
110 #define JSFRAME_ITERATOR      0x800 /* trying to get an iterator for for-in */
111 #define JSFRAME_POP_BLOCKS   0x1000 /* scope chain contains blocks to pop */
112 #define JSFRAME_GENERATOR    0x2000 /* frame belongs to generator-iterator */
113 
114 #define JSFRAME_OVERRIDE_SHIFT 24   /* override bit-set params; see jsfun.c */
115 #define JSFRAME_OVERRIDE_BITS  8
116 
117 /*
118  * Property cache for quickened get/set property opcodes.
119  */
120 #define PROPERTY_CACHE_LOG2     10
121 #define PROPERTY_CACHE_SIZE     JS_BIT(PROPERTY_CACHE_LOG2)
122 #define PROPERTY_CACHE_MASK     JS_BITMASK(PROPERTY_CACHE_LOG2)
123 
124 #define PROPERTY_CACHE_HASH(obj, id) \
125     ((((jsuword)(obj) >> JSVAL_TAGBITS) ^ (jsuword)(id)) & PROPERTY_CACHE_MASK)
126 
127 #ifdef JS_THREADSAFE
128 
129 #if HAVE_ATOMIC_DWORD_ACCESS
130 
131 #define PCE_LOAD(cache, pce, entry)     JS_ATOMIC_DWORD_LOAD(pce, entry)
132 #define PCE_STORE(cache, pce, entry)    JS_ATOMIC_DWORD_STORE(pce, entry)
133 
134 #else  /* !HAVE_ATOMIC_DWORD_ACCESS */
135 
136 #define JS_PROPERTY_CACHE_METERING      1
137 
138 #define PCE_LOAD(cache, pce, entry)                                           \
139     JS_BEGIN_MACRO                                                            \
140         uint32 prefills_;                                                     \
141         uint32 fills_ = (cache)->fills;                                       \
142         do {                                                                  \
143             /* Load until cache->fills is stable (see FILL macro below). */   \
144             prefills_ = fills_;                                               \
145             (entry) = *(pce);                                                 \
146         } while ((fills_ = (cache)->fills) != prefills_);                     \
147     JS_END_MACRO
148 
149 #define PCE_STORE(cache, pce, entry)                                          \
150     JS_BEGIN_MACRO                                                            \
151         do {                                                                  \
152             /* Store until no racing collider stores half or all of pce. */   \
153             *(pce) = (entry);                                                 \
154         } while (PCE_OBJECT(*pce) != PCE_OBJECT(entry) ||                     \
155                  PCE_PROPERTY(*pce) != PCE_PROPERTY(entry));                  \
156     JS_END_MACRO
157 
158 #endif /* !HAVE_ATOMIC_DWORD_ACCESS */
159 
160 #else  /* !JS_THREADSAFE */
161 
162 #define PCE_LOAD(cache, pce, entry)     ((entry) = *(pce))
163 #define PCE_STORE(cache, pce, entry)    (*(pce) = (entry))
164 
165 #endif /* !JS_THREADSAFE */
166 
167 typedef union JSPropertyCacheEntry {
168     struct {
169         JSObject        *object;        /* weak link to object */
170         JSScopeProperty *property;      /* weak link to property */
171     } s;
172 #ifdef HAVE_ATOMIC_DWORD_ACCESS
173     prdword align;
174 #endif
175 } JSPropertyCacheEntry;
176 
177 /* These may be called in lvalue or rvalue position. */
178 #define PCE_OBJECT(entry)       ((entry).s.object)
179 #define PCE_PROPERTY(entry)     ((entry).s.property)
180 
181 typedef struct JSPropertyCache {
182     JSPropertyCacheEntry table[PROPERTY_CACHE_SIZE];
183     JSBool               empty;
184     JSBool               disabled;
185 #ifdef JS_PROPERTY_CACHE_METERING
186     uint32               fills;
187     uint32               recycles;
188     uint32               tests;
189     uint32               misses;
190     uint32               flushes;
191 # define PCMETER(x)      x
192 #else
193 # define PCMETER(x)      /* nothing */
194 #endif
195 } JSPropertyCache;
196 
197 #define PROPERTY_CACHE_FILL(cache, obj, id, sprop)                            \
198     JS_BEGIN_MACRO                                                            \
199         JSPropertyCache *cache_ = (cache);                                    \
200         if (!cache_->disabled) {                                              \
201             uintN hashIndex_ = (uintN) PROPERTY_CACHE_HASH(obj, id);          \
202             JSPropertyCacheEntry *pce_ = &cache_->table[hashIndex_];          \
203             JSPropertyCacheEntry entry_;                                      \
204             JSScopeProperty *pce_sprop_;                                      \
205             PCE_LOAD(cache_, pce_, entry_);                                   \
206             pce_sprop_ = PCE_PROPERTY(entry_);                                \
207             PCMETER(if (pce_sprop_ && pce_sprop_ != sprop)                    \
208                         cache_->recycles++);                                  \
209             PCE_OBJECT(entry_) = obj;                                         \
210             PCE_PROPERTY(entry_) = sprop;                                     \
211             cache_->empty = JS_FALSE;                                         \
212             PCMETER(cache_->fills++);                                         \
213             PCE_STORE(cache_, pce_, entry_);                                  \
214         }                                                                     \
215     JS_END_MACRO
216 
217 #define PROPERTY_CACHE_TEST(cache, obj, id, sprop)                            \
218     JS_BEGIN_MACRO                                                            \
219         uintN hashIndex_ = (uintN) PROPERTY_CACHE_HASH(obj, id);              \
220         JSPropertyCache *cache_ = (cache);                                    \
221         JSPropertyCacheEntry *pce_ = &cache_->table[hashIndex_];              \
222         JSPropertyCacheEntry entry_;                                          \
223         JSScopeProperty *pce_sprop_;                                          \
224         PCE_LOAD(cache_, pce_, entry_);                                       \
225         pce_sprop_ = PCE_PROPERTY(entry_);                                    \
226         PCMETER(cache_->tests++);                                             \
227         if (pce_sprop_ &&                                                     \
228             PCE_OBJECT(entry_) == obj &&                                      \
229             pce_sprop_->id == id) {                                           \
230             sprop = pce_sprop_;                                               \
231         } else {                                                              \
232             PCMETER(cache_->misses++);                                        \
233             sprop = NULL;                                                     \
234         }                                                                     \
235     JS_END_MACRO
236 
237 extern void
238 js_FlushPropertyCache(JSContext *cx);
239 
240 extern void
241 js_DisablePropertyCache(JSContext *cx);
242 
243 extern void
244 js_EnablePropertyCache(JSContext *cx);
245 
246 extern JS_FRIEND_API(jsval *)
247 js_AllocStack(JSContext *cx, uintN nslots, void **markp);
248 
249 extern JS_FRIEND_API(void)
250 js_FreeStack(JSContext *cx, void *mark);
251 
252 extern JSBool
253 js_GetArgument(JSContext *cx, JSObject *obj, jsval id, jsval *vp);
254 
255 extern JSBool
256 js_SetArgument(JSContext *cx, JSObject *obj, jsval id, jsval *vp);
257 
258 extern JSBool
259 js_GetLocalVariable(JSContext *cx, JSObject *obj, jsval id, jsval *vp);
260 
261 extern JSBool
262 js_SetLocalVariable(JSContext *cx, JSObject *obj, jsval id, jsval *vp);
263 
264 #ifdef DUMP_CALL_TABLE
265 # define JSOPTION_LOGCALL_TOSOURCE JS_BIT(15)
266 
267 extern JSHashTable  *js_CallTable;
268 extern size_t       js_LogCallToSourceLimit;
269 
270 extern void         js_DumpCallTable(JSContext *cx);
271 #endif
272 
273 /*
274  * Refresh and return fp->scopeChain.  It may be stale if block scopes are
275  * active but not yet reflected by objects in the scope chain.  If a block
276  * scope contains a with, eval, XML filtering predicate, or similar such
277  * dynamically scoped construct, then compile-time block scope at fp->blocks
278  * must reflect at runtime.
279  */
280 extern JSObject *
281 js_GetScopeChain(JSContext *cx, JSStackFrame *fp);
282 
283 /*
284  * Compute the 'this' parameter for a call with nominal 'this' given by thisp
285  * and arguments including argv[-1] (nominal 'this') and argv[-2] (callee).
286  * Activation objects ("Call" objects not created with "new Call()", i.e.,
287  * "Call" objects that have private data) may not be referred to by 'this',
288  * per ECMA-262, so js_ComputeThis censors them.
289  */
290 extern JSObject *
291 js_ComputeThis(JSContext *cx, JSObject *thisp, jsval *argv);
292 
293 /*
294  * NB: js_Invoke requires that cx is currently running JS (i.e., that cx->fp
295  * is non-null), and that the callee, |this| parameter, and actual arguments
296  * are already pushed on the stack under cx->fp->sp.
297  */
298 extern JS_FRIEND_API(JSBool)
299 js_Invoke(JSContext *cx, uintN argc, uintN flags);
300 
301 /*
302  * Consolidated js_Invoke flags simply rename certain JSFRAME_* flags, so that
303  * we can share bits stored in JSStackFrame.flags and passed to:
304  *
305  *   js_Invoke
306  *   js_InternalInvoke
307  *   js_ValueToFunction
308  *   js_ValueToFunctionObject
309  *   js_ValueToCallableObject
310  *   js_ReportIsNotFunction
311  *
312  * See jsfun.h for the latter four and flag renaming macros.
313  */
314 #define JSINVOKE_CONSTRUCT      JSFRAME_CONSTRUCTING
315 #define JSINVOKE_INTERNAL       JSFRAME_INTERNAL
316 #define JSINVOKE_SKIP_CALLER    JSFRAME_SKIP_CALLER
317 #define JSINVOKE_ITERATOR       JSFRAME_ITERATOR
318 
319 /*
320  * Mask to isolate construct and iterator flags for use with jsfun.h functions.
321  */
322 #define JSINVOKE_FUNFLAGS       (JSINVOKE_CONSTRUCT | JSINVOKE_ITERATOR)
323 
324 /*
325  * "Internal" calls may come from C or C++ code using a JSContext on which no
326  * JS is running (!cx->fp), so they may need to push a dummy JSStackFrame.
327  */
328 #define js_InternalCall(cx,obj,fval,argc,argv,rval)                           \
329     js_InternalInvoke(cx, obj, fval, 0, argc, argv, rval)
330 
331 #define js_InternalConstruct(cx,obj,fval,argc,argv,rval)                      \
332     js_InternalInvoke(cx, obj, fval, JSINVOKE_CONSTRUCT, argc, argv, rval)
333 
334 extern JSBool
335 js_InternalInvoke(JSContext *cx, JSObject *obj, jsval fval, uintN flags,
336                   uintN argc, jsval *argv, jsval *rval);
337 
338 extern JSBool
339 js_InternalGetOrSet(JSContext *cx, JSObject *obj, jsid id, jsval fval,
340                     JSAccessMode mode, uintN argc, jsval *argv, jsval *rval);
341 
342 extern JSBool
343 js_Execute(JSContext *cx, JSObject *chain, JSScript *script,
344            JSStackFrame *down, uintN flags, jsval *result);
345 
346 extern JSBool
347 js_CheckRedeclaration(JSContext *cx, JSObject *obj, jsid id, uintN attrs,
348                       JSObject **objp, JSProperty **propp);
349 
350 extern JSBool
351 js_StrictlyEqual(jsval lval, jsval rval);
352 
353 extern JSBool
354 js_InvokeConstructor(JSContext *cx, jsval *vp, uintN argc);
355 
356 extern JSBool
357 js_Interpret(JSContext *cx, jsbytecode *pc, jsval *result);
358 
359 JS_END_EXTERN_C
360 
361 #endif /* jsinterp_h___ */
362