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Commitf13a912

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Fix issues ine8fdbd5.
When the 64bit atomics simulation is in use, we can't necessarilyguarantee the correct alignment of the atomics due to lack of compilersupport for doing so- that's fine from a safety perspective, becauseeverything is protected by a lock, but we asserted the alignment inall cases. Weaken them. Per complaint from Alvaro Herrera.My #ifdefery for PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY wasn'tsufficient. Fix that. Per complaint from Alexander Korotkov.
1 parent453aaf7 commitf13a912

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2 files changed

+62
-16
lines changed

2 files changed

+62
-16
lines changed

‎src/include/port/atomics.h

Lines changed: 27 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -425,82 +425,107 @@ pg_atomic_sub_fetch_u32(volatile pg_atomic_uint32 *ptr, int32 sub_)
425425
staticinlinevoid
426426
pg_atomic_init_u64(volatilepg_atomic_uint64*ptr,uint64val)
427427
{
428+
/*
429+
* Can't necessarily enforce alignment - and don't need it - when using
430+
* the spinlock based fallback implementation. Therefore only assert when
431+
* not using it.
432+
*/
433+
#ifndefPG_HAVE_ATOMIC_U64_SIMULATION
428434
AssertPointerAlignment(ptr,8);
429-
435+
#endif
430436
pg_atomic_init_u64_impl(ptr,val);
431437
}
432438

433439
staticinlineuint64
434440
pg_atomic_read_u64(volatilepg_atomic_uint64*ptr)
435441
{
442+
#ifndefPG_HAVE_ATOMIC_U64_SIMULATION
436443
AssertPointerAlignment(ptr,8);
444+
#endif
437445
returnpg_atomic_read_u64_impl(ptr);
438446
}
439447

440448
staticinlinevoid
441449
pg_atomic_write_u64(volatilepg_atomic_uint64*ptr,uint64val)
442450
{
451+
#ifndefPG_HAVE_ATOMIC_U64_SIMULATION
443452
AssertPointerAlignment(ptr,8);
453+
#endif
444454
pg_atomic_write_u64_impl(ptr,val);
445455
}
446456

447457
staticinlineuint64
448458
pg_atomic_exchange_u64(volatilepg_atomic_uint64*ptr,uint64newval)
449459
{
460+
#ifndefPG_HAVE_ATOMIC_U64_SIMULATION
450461
AssertPointerAlignment(ptr,8);
451-
462+
#endif
452463
returnpg_atomic_exchange_u64_impl(ptr,newval);
453464
}
454465

455466
staticinlinebool
456467
pg_atomic_compare_exchange_u64(volatilepg_atomic_uint64*ptr,
457468
uint64*expected,uint64newval)
458469
{
470+
#ifndefPG_HAVE_ATOMIC_U64_SIMULATION
459471
AssertPointerAlignment(ptr,8);
460472
AssertPointerAlignment(expected,8);
473+
#endif
461474
returnpg_atomic_compare_exchange_u64_impl(ptr,expected,newval);
462475
}
463476

464477
staticinlineuint64
465478
pg_atomic_fetch_add_u64(volatilepg_atomic_uint64*ptr,int64add_)
466479
{
480+
#ifndefPG_HAVE_ATOMIC_U64_SIMULATION
467481
AssertPointerAlignment(ptr,8);
482+
#endif
468483
returnpg_atomic_fetch_add_u64_impl(ptr,add_);
469484
}
470485

471486
staticinlineuint64
472487
pg_atomic_fetch_sub_u64(volatilepg_atomic_uint64*ptr,int64sub_)
473488
{
489+
#ifndefPG_HAVE_ATOMIC_U64_SIMULATION
474490
AssertPointerAlignment(ptr,8);
491+
#endif
475492
Assert(sub_!=PG_INT64_MIN);
476493
returnpg_atomic_fetch_sub_u64_impl(ptr,sub_);
477494
}
478495

479496
staticinlineuint64
480497
pg_atomic_fetch_and_u64(volatilepg_atomic_uint64*ptr,uint64and_)
481498
{
499+
#ifndefPG_HAVE_ATOMIC_U64_SIMULATION
482500
AssertPointerAlignment(ptr,8);
501+
#endif
483502
returnpg_atomic_fetch_and_u64_impl(ptr,and_);
484503
}
485504

486505
staticinlineuint64
487506
pg_atomic_fetch_or_u64(volatilepg_atomic_uint64*ptr,uint64or_)
488507
{
508+
#ifndefPG_HAVE_ATOMIC_U64_SIMULATION
489509
AssertPointerAlignment(ptr,8);
510+
#endif
490511
returnpg_atomic_fetch_or_u64_impl(ptr,or_);
491512
}
492513

493514
staticinlineuint64
494515
pg_atomic_add_fetch_u64(volatilepg_atomic_uint64*ptr,int64add_)
495516
{
517+
#ifndefPG_HAVE_ATOMIC_U64_SIMULATION
496518
AssertPointerAlignment(ptr,8);
519+
#endif
497520
returnpg_atomic_add_fetch_u64_impl(ptr,add_);
498521
}
499522

500523
staticinlineuint64
501524
pg_atomic_sub_fetch_u64(volatilepg_atomic_uint64*ptr,int64sub_)
502525
{
526+
#ifndefPG_HAVE_ATOMIC_U64_SIMULATION
503527
AssertPointerAlignment(ptr,8);
528+
#endif
504529
Assert(sub_!=PG_INT64_MIN);
505530
returnpg_atomic_sub_fetch_u64_impl(ptr,sub_);
506531
}

‎src/include/port/atomics/generic.h

Lines changed: 35 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -271,26 +271,26 @@ pg_atomic_exchange_u64_impl(volatile pg_atomic_uint64 *ptr, uint64 xchg_)
271271
}
272272
#endif
273273

274-
#ifndefPG_HAVE_ATOMIC_READ_U64
275-
#definePG_HAVE_ATOMIC_READ_U64
276-
staticinlineuint64
277-
pg_atomic_read_u64_impl(volatilepg_atomic_uint64*ptr)
278-
{
279-
return*(&ptr->value);
280-
}
281-
#endif
282-
283274
#ifndefPG_HAVE_ATOMIC_WRITE_U64
284275
#definePG_HAVE_ATOMIC_WRITE_U64
276+
277+
#if defined(PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY)&& \
278+
!defined(PG_HAVE_ATOMIC_U64_SIMULATION)
279+
285280
staticinlinevoid
286281
pg_atomic_write_u64_impl(volatilepg_atomic_uint64*ptr,uint64val)
287282
{
283+
/*
284+
* On this platform aligned 64bit writes are guaranteed to be atomic,
285+
* except if using the fallback implementation, where can't guarantee the
286+
* required alignment.
287+
*/
288+
AssertPointerAlignment(ptr,8);
288289
ptr->value=val;
289290
}
290-
#endif
291291

292-
#ifndefPG_HAVE_ATOMIC_WRITE_U64
293-
#definePG_HAVE_ATOMIC_WRITE_U64
292+
#else
293+
294294
staticinlinevoid
295295
pg_atomic_write_u64_impl(volatilepg_atomic_uint64*ptr,uint64val)
296296
{
@@ -300,10 +300,30 @@ pg_atomic_write_u64_impl(volatile pg_atomic_uint64 *ptr, uint64 val)
300300
*/
301301
pg_atomic_exchange_u64_impl(ptr,val);
302302
}
303-
#endif
303+
304+
#endif/* PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY && !PG_HAVE_ATOMIC_U64_SIMULATION */
305+
#endif/* PG_HAVE_ATOMIC_WRITE_U64 */
304306

305307
#ifndefPG_HAVE_ATOMIC_READ_U64
306308
#definePG_HAVE_ATOMIC_READ_U64
309+
310+
#if defined(PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY)&& \
311+
!defined(PG_HAVE_ATOMIC_U64_SIMULATION)
312+
313+
staticinlineuint64
314+
pg_atomic_read_u64_impl(volatilepg_atomic_uint64*ptr)
315+
{
316+
/*
317+
* On this platform aligned 64bit reads are guaranteed to be atomic,
318+
* except if using the fallback implementation, where can't guarantee the
319+
* required alignment.
320+
*/
321+
AssertPointerAlignment(ptr,8);
322+
return*(&ptr->value);
323+
}
324+
325+
#else
326+
307327
staticinlineuint64
308328
pg_atomic_read_u64_impl(volatilepg_atomic_uint64*ptr)
309329
{
@@ -319,7 +339,8 @@ pg_atomic_read_u64_impl(volatile pg_atomic_uint64 *ptr)
319339

320340
returnold;
321341
}
322-
#endif
342+
#endif/* PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY && !PG_HAVE_ATOMIC_U64_SIMULATION */
343+
#endif/* PG_HAVE_ATOMIC_READ_U64 */
323344

324345
#ifndefPG_HAVE_ATOMIC_INIT_U64
325346
#definePG_HAVE_ATOMIC_INIT_U64

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