aboutsummaryrefslogtreecommitdiffstats
path: root/erts/emulator/beam/export.c
blob: e5d9da187a19f07ccb7f239ba5f53756371ffd4f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
/*
 * %CopyrightBegin%
 *
 * Copyright Ericsson AB 1996-2011. All Rights Reserved.
 *
 * The contents of this file are subject to the Erlang Public License,
 * Version 1.1, (the "License"); you may not use this file except in
 * compliance with the License. You should have received a copy of the
 * Erlang Public License along with this software. If not, it can be
 * retrieved online at http://www.erlang.org/.
 *
 * 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.
 *
 * %CopyrightEnd%
 */

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#include "sys.h"
#include "erl_vm.h"
#include "global.h"
#include "export.h"
#include "hash.h"

#define EXPORT_INITIAL_SIZE   4000
#define EXPORT_LIMIT  (512*1024)

#define EXPORT_HASH(m,f,a) ((m)*(f)+(a))

#ifdef DEBUG
#  define IF_DEBUG(x) x
#else
#  define IF_DEBUG(x)
#endif

static IndexTable export_tables[ERTS_NUM_CODE_IX];  /* Active not locked */
static Hash secondary_export_table; /* Locked. */

#include "erl_smp.h"

static erts_smp_rwmtx_t export_table_lock; /* Locks the secondary export table. */

#define export_read_lock()	erts_smp_rwmtx_rlock(&export_table_lock)
#define export_read_unlock()	erts_smp_rwmtx_runlock(&export_table_lock)
#define export_write_lock()	erts_smp_rwmtx_rwlock(&export_table_lock)
#define export_write_unlock()	erts_smp_rwmtx_rwunlock(&export_table_lock)

extern BeamInstr* em_call_error_handler;
extern BeamInstr* em_call_traced_function;

struct export_entry
{
    IndexSlot slot; /* MUST BE LOCATED AT TOP OF STRUCT!!! */
    Export* ep;
};

/* Helper struct that brings things together in one allocation
*/
struct export_blob
{
    Export exp;
    unsigned top_ix;  /*SVERK atomic? */
    struct export_entry entryv[ERTS_NUM_CODE_IX];
};

/* Helper struct only used as template
*/
struct export_templ
{
    struct export_entry entry;
    Export exp;
};


void
export_info(int to, void *to_arg)
{
#ifdef ERTS_SMP
    int lock = !ERTS_IS_CRASH_DUMPING;
    if (lock)
	export_read_lock();
#endif
    index_info(to, to_arg, &export_tables[erts_active_code_ix()]);
    hash_info(to, to_arg, &secondary_export_table);
#ifdef ERTS_SMP
    if (lock)
	export_read_unlock();
#endif
}


static HashValue
export_hash(struct export_entry* ee)
{
    Export* x = ee->ep;
    return EXPORT_HASH(x->code[0], x->code[1], x->code[2]);
}

static int
export_cmp(struct export_entry* tmpl_e, struct export_entry* obj_e)
{
    Export* tmpl = tmpl_e->ep;
    Export* obj = obj_e->ep;
    return !(tmpl->code[0] == obj->code[0] &&
	     tmpl->code[1] == obj->code[1] &&
	     tmpl->code[2] == obj->code[2]);
}


static struct export_entry*
export_alloc(struct export_entry* tmpl_e)
{

    Export* tmpl = tmpl_e->ep;
    struct export_blob* blob =
	(struct export_blob*) erts_alloc(ERTS_ALC_T_EXPORT, sizeof(*blob));
    Export* obj = &blob->exp;
    int i;

    obj->fake_op_func_info_for_hipe[0] = 0;
    obj->fake_op_func_info_for_hipe[1] = 0;
    obj->code[0] = tmpl->code[0];
    obj->code[1] = tmpl->code[1];
    obj->code[2] = tmpl->code[2];
    obj->code[3] = (BeamInstr) em_call_error_handler;
    obj->code[4] = 0;
    obj->match_prog_set = NULL;

    for (i=0; i<ERTS_NUM_CODE_IX; i++) {
	obj->addressv[i] = obj->code+3;

	blob->entryv[i].slot.index = -1;
	blob->entryv[i].ep = &blob->exp;
    }
    blob->top_ix = 0;
    return &blob->entryv[blob->top_ix];
}

/*SVERK
static void 
export_free(struct export_entry* obj)
{
    erts_free(ERTS_ALC_T_EXPORT,  (void*) obj);
}
*/

void
init_export_table(void)
{
    HashFunctions f;
    erts_smp_rwmtx_opt_t rwmtx_opt = ERTS_SMP_RWMTX_OPT_DEFAULT_INITER;
    int i;
    rwmtx_opt.type = ERTS_SMP_RWMTX_TYPE_FREQUENT_READ;
    rwmtx_opt.lived = ERTS_SMP_RWMTX_LONG_LIVED;

    erts_smp_rwmtx_init_opt(&export_table_lock, &rwmtx_opt, "export_tab");

    f.hash = (H_FUN) export_hash;
    f.cmp  = (HCMP_FUN) export_cmp;
    f.alloc = (HALLOC_FUN) export_alloc;
    f.free = (HFREE_FUN) NULL; /*SVERK export_free;*/

    for (i=0; i<ERTS_NUM_CODE_IX; i++) {
	erts_index_init(ERTS_ALC_T_EXPORT_TABLE, &export_tables[i], "export_list",
			EXPORT_INITIAL_SIZE, EXPORT_LIMIT, f);
    }
    hash_init(ERTS_ALC_T_EXPORT_TABLE, &secondary_export_table,
	      "secondary_export_table", 50, f);
}

/*
 * Return a pointer to the export entry for the given function,
 * or NULL otherwise.  Notes:
 *
 * 1) BIFs have export entries and can be called through
 *    a wrapper in the export entry.
 * 2) Functions referenced by a loaded module, but not yet loaded
 *    also have export entries.  The export entry contains
 *    a wrapper which invokes the error handler if a function is
 *    called through such an export entry.
 * 3) This function is suitable for the implementation of erlang:apply/3.
 */

Export*
erts_active_export_entry(Eterm m, Eterm f, unsigned int a)
{
    return erts_find_export_entry(m, f, a, erts_active_code_ix());
}

static void sverk_break(void)
{
}

Export*
erts_find_export_entry(Eterm m, Eterm f, unsigned int a,
		       ErtsCodeIndex code_ix)
{
    HashValue hval = EXPORT_HASH((BeamInstr) m, (BeamInstr) f, (BeamInstr) a);
    int ix;
    HashBucket* b;

    if (ERTS_IS_ATOM_STR("gen_event",m) && ERTS_IS_ATOM_STR("add_handler",f)) {
	sverk_break();
    }

    ix = hval % export_tables[code_ix].htable.size;
    b = export_tables[code_ix].htable.bucket[ix];

    /*
     * Note: We have inlined the code from hash.c for speed.
     */
	
    while (b != (HashBucket*) 0) {
	Export* ep = ((struct export_entry*) b)->ep;
	if (ep->code[0] == m && ep->code[1] == f && ep->code[2] == a) {
	    return ep;
	}
	b = b->next;
    }
    return NULL;
}

static struct export_entry* init_template(struct export_templ* templ,
					  Eterm m, Eterm f, unsigned a)
{
    templ->entry.ep = &templ->exp;
    templ->entry.slot.index = -1;
    templ->exp.code[0] = m;
    templ->exp.code[1] = f;
    templ->exp.code[2] = a;
    return &templ->entry;
}


/*
 * Find the export entry for a loaded function.
 * Returns a NULL pointer if the given function is not loaded, or
 * a pointer to the export entry.
 *
 * Note: This function never returns export entries for BIFs
 * or functions which are not yet loaded.  This makes it suitable
 * for use by the erlang:function_exported/3 BIF or whenever you
 * cannot depend on the error_handler.
 */

Export*
erts_find_function(Eterm m, Eterm f, unsigned int a, ErtsCodeIndex code_ix)
{
    struct export_templ templ;
    struct export_entry* ee;

    ee = hash_get(&export_tables[code_ix].htable, init_template(&templ, m, f, a));
    if (ee == NULL || (ee->ep->addressv[code_ix] == ee->ep->code+3 &&
		       ee->ep->code[3] != (BeamInstr) em_call_traced_function)) {
	return NULL;
    }
    return ee->ep;
}

/*
 * Returns a pointer to an existing export entry for a MFA,
 * or creates a new one and returns the pointer.
 *
 * This function provides unlocked write access to the main export
 * table. It should only be used during start up or when
 * all other threads are blocked.
 */

Export*
erts_export_put(Eterm mod, Eterm func, unsigned int arity)
{
    ErtsCodeIndex code_ix = erts_loader_code_ix();
    struct export_templ templ;
    int ix;

    if (ERTS_IS_ATOM_STR("gen_event",mod) && ERTS_IS_ATOM_STR("add_handler",func)) {
	sverk_break();
    }

    ASSERT(is_atom(mod));
    ASSERT(is_atom(func));
    ix = index_put(&export_tables[code_ix], init_template(&templ, mod, func, arity));
    return ((struct export_entry*) erts_index_lookup(&export_tables[code_ix], ix))->ep;
}

/*
 * Find the existing export entry for M:F/A. Failing that, create a stub
 * export entry (making a call through it will cause the error_handler to
 * be called).
 *
 * Stub export entries will be placed in the secondary export table.
 * erts_export_consolidate() will move all stub export entries into the
 * main export table (will be done the next time code is loaded).
 */

Export*
erts_export_get_or_make_stub(Eterm mod, Eterm func, unsigned int arity)
{
    Export* ep;
    
    ASSERT(is_atom(mod));
    ASSERT(is_atom(func));
    
    ep = erts_active_export_entry(mod, func, arity);
    if (ep == 0) {
	struct export_templ templ;
	struct export_entry* entry;
	/*
	 * The code is not loaded (yet). Put the export in the secondary
	 * export table, to avoid having to lock the main export table.
	 */
	export_write_lock();
	entry = (struct export_entry *) hash_put(&secondary_export_table,
						 init_template(&templ, mod, func, arity));
	export_write_unlock();
	ep = entry->ep;
    }
    return ep;
}

/*
 * To be called before loading code (with other threads blocked).
 * This function will move all export entries from the secondary
 * export table into the primary.
 */
void
erts_export_consolidate(ErtsCodeIndex code_ix)
{
#ifdef DEBUG
    HashInfo hi;
#endif

    /*SVERK: Not sure if this is the way to go.
             Maye we should always merge into loader ix,
             or can loader table act as secondary_export_table?*/

    ERTS_SMP_LC_ASSERT((erts_is_code_ix_locked()
			&& code_ix == erts_loader_code_ix())
		       || erts_initialized == 0
		       || erts_smp_thr_progress_is_blocking());

    export_write_lock();
    erts_index_merge(&secondary_export_table, &export_tables[code_ix]);
    erts_hash_merge(&secondary_export_table, &export_tables[code_ix].htable);
    export_write_unlock();
#ifdef DEBUG
    hash_get_info(&hi, &export_tables[code_ix].htable);
    ASSERT(export_tables[code_ix].entries == hi.objs);
#endif
}

Export *export_list(int i, ErtsCodeIndex code_ix)
{
    return ((struct export_entry*) erts_index_lookup(&export_tables[code_ix], i))->ep;
}

int export_list_size(ErtsCodeIndex code_ix)
{
    return export_tables[code_ix].entries;
}

int export_table_sz(void)
{
    return index_table_sz(&export_tables[erts_active_code_ix()]);
}

Export *export_get(Export *e)
{
    struct export_entry ee;
    struct export_entry* entry;

    if (ERTS_IS_ATOM_STR("gen_event",e->code[0]) && ERTS_IS_ATOM_STR("add_handler",e->code[1])) {
	sverk_break();
    }
    ee.ep = e;
    entry = (struct export_entry*)hash_get(&export_tables[erts_active_code_ix()].htable, &ee);
    return entry ? entry->ep : NULL;
}

static struct export_entry*
export_dummy_alloc(struct export_entry* entry)
{
    return entry;
}

static struct export_blob* entry_to_blob(struct export_entry* ee)
{
    return (struct export_blob*)
        ((char*)ee->ep - offsetof(struct export_blob,exp));
}

IF_DEBUG(static ErtsCodeIndex debug_start_load_ix = 0;)

void export_start_load(void)
{
    ErtsCodeIndex dst_ix = erts_loader_code_ix();
    ErtsCodeIndex src_ix = erts_active_code_ix();
    IndexTable* dst = &export_tables[dst_ix];
    IndexTable* src = &export_tables[src_ix];
    struct export_entry* src_entry;
    struct export_entry* dst_entry;
    struct export_blob* blob;
    int i;

    ASSERT(dst_ix != src_ix);
    ASSERT(dst->entries <= src->entries);
    ASSERT(debug_start_load_ix == -1);

    /*
     * Make sure our existing entries are up to date
     */
    for (i = 0; i < dst->entries; i++) {
	src_entry = (struct export_entry*) erts_index_lookup(src, i);
	blob = entry_to_blob(src_entry);
	blob->exp.addressv[dst_ix] = blob->exp.addressv[src_ix];
    }

    /*
     * Insert all new entries from active table
     */

    /* Trick hash_put (called by index_put) to insert existing entries. */
    dst->htable.fun.alloc = (HALLOC_FUN) &export_dummy_alloc;

    for (i = dst->entries; i < src->entries; i++) {
	src_entry = (struct export_entry*) erts_index_lookup(src, i);
	blob = entry_to_blob(src_entry);
	dst_entry = &blob->entryv[++blob->top_ix];
	blob->exp.addressv[dst_ix] = blob->exp.addressv[src_ix];
	ASSERT(blob->top_ix < ERTS_NUM_CODE_IX);
	ASSERT(dst_entry->ep == &blob->exp);
	ASSERT(dst_entry->slot.index == -1);
	index_put(dst, dst_entry);
    }

    dst->htable.fun.alloc = (HALLOC_FUN) &export_alloc; /* restore */

    /*SVERK Remember dst->entries in order to purge on abort */

    IF_DEBUG(debug_start_load_ix = dst_ix);
}

void export_end_load(int commit)
{
    ASSERT(debug_start_load_ix == erts_loader_code_ix());

    /*SVERK Purge if abort */

    IF_DEBUG(debug_start_load_ix = -1);
}