js/src/jslock.h

   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
  30  * of those above. If you wish to allow use of your version of this file only
  31  * under the terms of either the GPL or the LGPL, and not to allow others to
  32  * use your version of this file under the terms of the MPL, indicate your
  33  * decision by deleting the provisions above and replace them with the notice
  34  * and other provisions required by the GPL or the LGPL. If you do not delete
  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 #ifndef jslock_h__
  40 #define jslock_h__
  41
  42 #include "jstypes.h"
  43 #include "jsprvtd.h"    /* for JSScope, etc. */
  44 #include "jspubtd.h"    /* for JSRuntime, etc. */
  45
  46 #ifdef JS_THREADSAFE
  47 # include "pratom.h"
  48 # include "prlock.h"
  49 # include "prcvar.h"
  50 # include "prthread.h"
  51 #endif
  52
  53 JS_BEGIN_EXTERN_C
  54
  55 #ifdef JS_THREADSAFE
  56
  57 #if (defined(_WIN32) && defined(_M_IX86)) ||                                  \
  58     (defined(_WIN64) && (defined(_M_AMD64) || defined(_M_X64))) ||            \
  59     (defined(__i386) && (defined(__GNUC__) || defined(__SUNPRO_CC))) ||       \
  60     (defined(__x86_64) && (defined(__GNUC__) || defined(__SUNPRO_CC))) ||     \
  61     (defined(__sparc) && (defined(__GNUC__) || defined(__SUNPRO_CC))) ||      \
  62     defined(AIX) ||                                                           \
  63     defined(USE_ARM_KUSER)
  64 # define JS_HAS_NATIVE_COMPARE_AND_SWAP 1
  65 #else
  66 # define JS_HAS_NATIVE_COMPARE_AND_SWAP 0
  67 #endif
  68
  69 #if defined(JS_USE_ONLY_NSPR_LOCKS) || !JS_HAS_NATIVE_COMPARE_AND_SWAP
  70 # define NSPR_LOCK 1
  71 #else
  72 # undef NSPR_LOCK
  73 #endif
  74
  75 #define Thin_GetWait(W) ((jsword)(W) & 0x1)
  76 #define Thin_SetWait(W) ((jsword)(W) | 0x1)
  77 #define Thin_RemoveWait(W) ((jsword)(W) & ~0x1)
  78
  79 typedef struct JSFatLock JSFatLock;
  80
  81 typedef struct JSThinLock {
  82     jsword      owner;
  83     JSFatLock   *fat;
  84 } JSThinLock;
  85
  86 #define CX_THINLOCK_ID(cx)       ((jsword)(cx)->thread)
  87 #define CURRENT_THREAD_IS_ME(me) (((JSThread *)me)->id == js_CurrentThreadId())
  88
  89 typedef PRLock JSLock;
  90
  91 typedef struct JSTitle JSTitle;
  92
  93 struct JSTitle {
  94     JSContext       *ownercx;           /* creating context, NULL if shared */
  95     JSThinLock      lock;               /* binary semaphore protecting title */
  96     union {                             /* union lockful and lock-free state: */
  97         jsrefcount  count;              /* lock entry count for reentrancy */
  98         JSTitle     *link;              /* next link in rt->titleSharingTodo */
  99     } u;
 100 #ifdef JS_DEBUG_TITLE_LOCKS
 101     const char      *file[4];           /* file where lock was (re-)taken */
 102     unsigned int    line[4];            /* line where lock was (re-)taken */
 103 #endif
 104 };
 105
 106 /*
 107  * Title structure is always allocated as a field of JSScope.
 108  */
 109 #define TITLE_TO_SCOPE(title)                                                 \
 110     ((JSScope *)((uint8 *) (title) - offsetof(JSScope, title)))
 111
 112 /*
 113  * Atomic increment and decrement for a reference counter, given jsrefcount *p.
 114  * NB: jsrefcount is int32, aka PRInt32, so that pratom.h functions work.
 115  */
 116 #define JS_ATOMIC_INCREMENT(p)      PR_AtomicIncrement((PRInt32 *)(p))
 117 #define JS_ATOMIC_DECREMENT(p)      PR_AtomicDecrement((PRInt32 *)(p))
 118 #define JS_ATOMIC_ADD(p,v)          PR_AtomicAdd((PRInt32 *)(p), (PRInt32)(v))
 119 #define JS_ATOMIC_SET(p,v)          PR_AtomicSet((PRInt32 *)(p), (PRInt32)(v))
 120
 121 #define js_CurrentThreadId()        (jsword)PR_GetCurrentThread()
 122 #define JS_NEW_LOCK()               PR_NewLock()
 123 #define JS_DESTROY_LOCK(l)          PR_DestroyLock(l)
 124 #define JS_ACQUIRE_LOCK(l)          PR_Lock(l)
 125 #define JS_RELEASE_LOCK(l)          PR_Unlock(l)
 126
 127 #define JS_NEW_CONDVAR(l)           PR_NewCondVar(l)
 128 #define JS_DESTROY_CONDVAR(cv)      PR_DestroyCondVar(cv)
 129 #define JS_WAIT_CONDVAR(cv,to)      PR_WaitCondVar(cv,to)
 130 #define JS_NO_TIMEOUT               PR_INTERVAL_NO_TIMEOUT
 131 #define JS_NOTIFY_CONDVAR(cv)       PR_NotifyCondVar(cv)
 132 #define JS_NOTIFY_ALL_CONDVAR(cv)   PR_NotifyAllCondVar(cv)
 133
 134 #ifdef JS_DEBUG_TITLE_LOCKS
 135
 136 #define JS_SET_OBJ_INFO(obj_, file_, line_)                                   \
 137     JS_SET_SCOPE_INFO(OBJ_SCOPE(obj_), file_, line_)
 138
 139 #define JS_SET_SCOPE_INFO(scope_, file_, line_)                               \
 140     js_SetScopeInfo(scope_, file_, line_)
 141
 142 #endif
 143
 144 #define JS_LOCK(cx, tl)             js_Lock(cx, tl)
 145 #define JS_UNLOCK(cx, tl)           js_Unlock(cx, tl)
 146
 147 #define JS_LOCK_RUNTIME(rt)         js_LockRuntime(rt)
 148 #define JS_UNLOCK_RUNTIME(rt)       js_UnlockRuntime(rt)
 149
 150 /*
 151  * NB: The JS_LOCK_OBJ and JS_UNLOCK_OBJ macros work *only* on native objects
 152  * (objects for which OBJ_IS_NATIVE returns true).  All uses of these macros in
 153  * the engine are predicated on OBJ_IS_NATIVE or equivalent checks.  These uses
 154  * are for optimizations above the JSObjectOps layer, under which object locks
 155  * normally hide.
 156  */
 157 #define JS_LOCK_OBJ(cx,obj)       ((OBJ_SCOPE(obj)->title.ownercx == (cx))    \
 158                                    ? (void)0                                  \
 159                                    : (js_LockObj(cx, obj),                    \
 160                                       JS_SET_OBJ_INFO(obj,__FILE__,__LINE__)))
 161 #define JS_UNLOCK_OBJ(cx,obj)     ((OBJ_SCOPE(obj)->title.ownercx == (cx))    \
 162                                    ? (void)0 : js_UnlockObj(cx, obj))
 163
 164 /*
 165  * Lock object only if its scope has the given shape.
 166  */
 167 #define JS_LOCK_OBJ_IF_SHAPE(cx,obj,shape)                                    \
 168     (OBJ_SHAPE(obj) == (shape)                                                \
 169      ? (OBJ_SCOPE(obj)->title.ownercx == (cx)                                 \
 170         ? true                                                                \
 171         : js_LockObjIfShape(cx, obj, shape))                                  \
 172      : false)
 173
 174 #define JS_LOCK_TITLE(cx,title)                                               \
 175     ((title)->ownercx == (cx) ? (void)0                                       \
 176      : (js_LockTitle(cx, (title)),                                            \
 177         JS_SET_TITLE_INFO(title,__FILE__,__LINE__)))
 178
 179 #define JS_UNLOCK_TITLE(cx,title) ((title)->ownercx == (cx) ? (void)0         \
 180                                    : js_UnlockTitle(cx, title))
 181
 182 #define JS_LOCK_SCOPE(cx,scope)   JS_LOCK_TITLE(cx,&(scope)->title)
 183 #define JS_UNLOCK_SCOPE(cx,scope) JS_UNLOCK_TITLE(cx,&(scope)->title)
 184
 185 #define JS_TRANSFER_SCOPE_LOCK(cx, scope, newscope)                           \
 186     js_TransferTitle(cx, &scope->title, &newscope->title)
 187
 188
 189 extern void js_Lock(JSContext *cx, JSThinLock *tl);
 190 extern void js_Unlock(JSContext *cx, JSThinLock *tl);
 191 extern void js_LockRuntime(JSRuntime *rt);
 192 extern void js_UnlockRuntime(JSRuntime *rt);
 193 extern void js_LockObj(JSContext *cx, JSObject *obj);
 194 extern void js_UnlockObj(JSContext *cx, JSObject *obj);
 195 extern bool js_LockObjIfShape(JSContext *cx, JSObject *obj, uint32 shape);
 196 extern void js_InitTitle(JSContext *cx, JSTitle *title);
 197 extern void js_FinishTitle(JSContext *cx, JSTitle *title);
 198 extern void js_LockTitle(JSContext *cx, JSTitle *title);
 199 extern void js_UnlockTitle(JSContext *cx, JSTitle *title);
 200 extern int js_SetupLocks(int,int);
 201 extern void js_CleanupLocks();
 202 extern void js_TransferTitle(JSContext *, JSTitle *, JSTitle *);
 203 extern JS_FRIEND_API(jsval)
 204 js_GetSlotThreadSafe(JSContext *, JSObject *, uint32);
 205 extern void js_SetSlotThreadSafe(JSContext *, JSObject *, uint32, jsval);
 206 extern void js_InitLock(JSThinLock *);
 207 extern void js_FinishLock(JSThinLock *);
 208
 209 /*
 210  * This function must be called with the GC lock held.
 211  */
 212 extern void
 213 js_ShareWaitingTitles(JSContext *cx);
 214
 215 extern void
 216 js_NudgeOtherContexts(JSContext *cx);
 217
 218 #ifdef DEBUG
 219
 220 #define JS_IS_RUNTIME_LOCKED(rt)        js_IsRuntimeLocked(rt)
 221 #define JS_IS_OBJ_LOCKED(cx,obj)        js_IsObjLocked(cx,obj)
 222 #define JS_IS_TITLE_LOCKED(cx,title)    js_IsTitleLocked(cx,title)
 223
 224 extern JSBool js_IsRuntimeLocked(JSRuntime *rt);
 225 extern JSBool js_IsObjLocked(JSContext *cx, JSObject *obj);
 226 extern JSBool js_IsTitleLocked(JSContext *cx, JSTitle *title);
 227 #ifdef JS_DEBUG_TITLE_LOCKS
 228 extern void js_SetScopeInfo(JSScope *scope, const char *file, int line);
 229 #endif
 230
 231 #else
 232
 233 #define JS_IS_RUNTIME_LOCKED(rt)        0
 234 #define JS_IS_OBJ_LOCKED(cx,obj)        1
 235 #define JS_IS_TITLE_LOCKED(cx,title)    1
 236
 237 #endif /* DEBUG */
 238
 239 #define JS_LOCK_OBJ_VOID(cx, obj, e)                                          \
 240     JS_BEGIN_MACRO                                                            \
 241         JS_LOCK_OBJ(cx, obj);                                                 \
 242         e;                                                                    \
 243         JS_UNLOCK_OBJ(cx, obj);                                               \
 244     JS_END_MACRO
 245
 246 #define JS_LOCK_VOID(cx, e)                                                   \
 247     JS_BEGIN_MACRO                                                            \
 248         JSRuntime *_rt = (cx)->runtime;                                       \
 249         JS_LOCK_RUNTIME_VOID(_rt, e);                                         \
 250     JS_END_MACRO
 251
 252 #else  /* !JS_THREADSAFE */
 253
 254 #define JS_ATOMIC_INCREMENT(p)      (++*(p))
 255 #define JS_ATOMIC_DECREMENT(p)      (--*(p))
 256 #define JS_ATOMIC_ADD(p,v)          (*(p) += (v))
 257 #define JS_ATOMIC_SET(p,v)          (*(p) = (v))
 258
 259 #define JS_CurrentThreadId() 0
 260 #define JS_NEW_LOCK()               NULL
 261 #define JS_DESTROY_LOCK(l)          ((void)0)
 262 #define JS_ACQUIRE_LOCK(l)          ((void)0)
 263 #define JS_RELEASE_LOCK(l)          ((void)0)
 264 #define JS_LOCK(cx, tl)             ((void)0)
 265 #define JS_UNLOCK(cx, tl)           ((void)0)
 266
 267 #define JS_NEW_CONDVAR(l)           NULL
 268 #define JS_DESTROY_CONDVAR(cv)      ((void)0)
 269 #define JS_WAIT_CONDVAR(cv,to)      ((void)0)
 270 #define JS_NOTIFY_CONDVAR(cv)       ((void)0)
 271 #define JS_NOTIFY_ALL_CONDVAR(cv)   ((void)0)
 272
 273 #define JS_LOCK_RUNTIME(rt)         ((void)0)
 274 #define JS_UNLOCK_RUNTIME(rt)       ((void)0)
 275 #define JS_LOCK_OBJ(cx,obj)         ((void)0)
 276 #define JS_UNLOCK_OBJ(cx,obj)       ((void)0)
 277 #define JS_LOCK_OBJ_IF_SHAPE(cx,obj,shape) (OBJ_SHAPE(obj) == (shape))
 278
 279 #define JS_LOCK_OBJ_VOID(cx,obj,e)  (e)
 280 #define JS_LOCK_SCOPE(cx,scope)     ((void)0)
 281 #define JS_UNLOCK_SCOPE(cx,scope)   ((void)0)
 282 #define JS_TRANSFER_SCOPE_LOCK(c,o,n) ((void)0)
 283
 284 #define JS_IS_RUNTIME_LOCKED(rt)        1
 285 #define JS_IS_OBJ_LOCKED(cx,obj)        1
 286 #define JS_IS_TITLE_LOCKED(cx,title)    1
 287 #define JS_LOCK_VOID(cx, e)             JS_LOCK_RUNTIME_VOID((cx)->runtime, e)
 288
 289 #endif /* !JS_THREADSAFE */
 290
 291 #define JS_LOCK_RUNTIME_VOID(rt,e)                                            \
 292     JS_BEGIN_MACRO                                                            \
 293         JS_LOCK_RUNTIME(rt);                                                  \
 294         e;                                                                    \
 295         JS_UNLOCK_RUNTIME(rt);                                                \
 296     JS_END_MACRO
 297
 298 #define JS_LOCK_GC(rt)              JS_ACQUIRE_LOCK((rt)->gcLock)
 299 #define JS_UNLOCK_GC(rt)            JS_RELEASE_LOCK((rt)->gcLock)
 300 #define JS_LOCK_GC_VOID(rt,e)       (JS_LOCK_GC(rt), (e), JS_UNLOCK_GC(rt))
 301 #define JS_AWAIT_GC_DONE(rt)        JS_WAIT_CONDVAR((rt)->gcDone, JS_NO_TIMEOUT)
 302 #define JS_NOTIFY_GC_DONE(rt)       JS_NOTIFY_ALL_CONDVAR((rt)->gcDone)
 303 #define JS_AWAIT_REQUEST_DONE(rt)   JS_WAIT_CONDVAR((rt)->requestDone,        \
 304                                                     JS_NO_TIMEOUT)
 305 #define JS_NOTIFY_REQUEST_DONE(rt)  JS_NOTIFY_CONDVAR((rt)->requestDone)
 306
 307 #ifndef JS_SET_OBJ_INFO
 308 #define JS_SET_OBJ_INFO(obj,f,l)        ((void)0)
 309 #endif
 310 #ifndef JS_SET_TITLE_INFO
 311 #define JS_SET_TITLE_INFO(title,f,l)    ((void)0)
 312 #endif
 313
 314 #ifdef JS_THREADSAFE
 315
 316 extern JSBool
 317 js_CompareAndSwap(jsword *w, jsword ov, jsword nv);
 318
 319 /* Atomically bitwise-or the mask into the word *w using compare and swap. */
 320 extern void
 321 js_AtomicSetMask(jsword *w, jsword mask);
 322
 323 #define JS_ATOMIC_SET_MASK(w, mask) js_AtomicSetMask(w, mask)
 324
 325 #else
 326
 327 static inline JSBool
 328 js_CompareAndSwap(jsword *w, jsword ov, jsword nv)
 329 {
 330     return (*w == ov) ? *w = nv, JS_TRUE : JS_FALSE;
 331 }
 332
 333 #define JS_ATOMIC_SET_MASK(w, mask) (*(w) |= (mask))
 334
 335 #endif /* JS_THREADSAFE */
 336
 337 JS_END_EXTERN_C
 338
 339 #endif /* jslock_h___ */