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Overview
| Comment: | Back out the use of __sync_fetch_and_sub() as it does not appear to work. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | gnu-safe-math |
| Files: | files | file ages | folders |
| SHA1: |
4c2efd4239bf07eb4b92d4af54edd68e |
| User & Date: | drh 2017-01-03 21:50:49 |
Context
|
2017-01-03
| ||
| 21:57 | Use compiler intrinsic functions for signed integer math when overflow detection is needed. (check-in: d3ac32a6 user: drh tags: trunk) | |
| 21:50 | Back out the use of __sync_fetch_and_sub() as it does not appear to work. (Closed-Leaf check-in: 4c2efd42 user: drh tags: gnu-safe-math) | |
| 21:03 | Fix a typo in a comment. (check-in: ae087123 user: drh tags: gnu-safe-math) | |
| 18:05 | Use the GCC built-in __sync_fetch_and_sub() to make the sqlite3StatusDown() routine atomic, and thereby avoid some mutexing. (check-in: f69ce75b user: drh tags: gnu-safe-math) | |
Changes
Changes to src/malloc.c.
372 372 }else{ 373 373 /* Release memory back to the heap */ 374 374 assert( sqlite3MemdebugHasType(p, MEMTYPE_SCRATCH) ); 375 375 assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_SCRATCH) ); 376 376 sqlite3MemdebugSetType(p, MEMTYPE_HEAP); 377 377 if( sqlite3GlobalConfig.bMemstat ){ 378 378 int iSize = sqlite3MallocSize(p); 379 -#ifndef SQLITE_ATOMIC_STATUS_DOWN 380 379 sqlite3_mutex_enter(mem0.mutex); 381 -#endif 382 380 sqlite3StatusDown(SQLITE_STATUS_SCRATCH_OVERFLOW, iSize); 383 381 sqlite3StatusDown(SQLITE_STATUS_MEMORY_USED, iSize); 384 382 sqlite3StatusDown(SQLITE_STATUS_MALLOC_COUNT, 1); 385 383 sqlite3GlobalConfig.m.xFree(p); 386 -#ifndef SQLITE_ATOMIC_STATUS_DOWN 387 384 sqlite3_mutex_leave(mem0.mutex); 388 -#endif 389 385 }else{ 390 386 sqlite3GlobalConfig.m.xFree(p); 391 387 } 392 388 } 393 389 } 394 390 } 395 391 ................................................................................ 440 436 ** Free memory previously obtained from sqlite3Malloc(). 441 437 */ 442 438 void sqlite3_free(void *p){ 443 439 if( p==0 ) return; /* IMP: R-49053-54554 */ 444 440 assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) ); 445 441 assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) ); 446 442 if( sqlite3GlobalConfig.bMemstat ){ 447 -#ifndef SQLITE_ATOMIC_STATUS_DOWN 448 443 sqlite3_mutex_enter(mem0.mutex); 449 -#endif 450 444 sqlite3StatusDown(SQLITE_STATUS_MEMORY_USED, sqlite3MallocSize(p)); 451 445 sqlite3StatusDown(SQLITE_STATUS_MALLOC_COUNT, 1); 452 446 sqlite3GlobalConfig.m.xFree(p); 453 -#ifndef SQLITE_ATOMIC_STATUS_DOWN 454 447 sqlite3_mutex_leave(mem0.mutex); 455 -#endif 456 448 }else{ 457 449 sqlite3GlobalConfig.m.xFree(p); 458 450 } 459 451 } 460 452 461 453 /* 462 454 ** Add the size of memory allocation "p" to the count in
Changes to src/sqliteInt.h.
232 232 # define SQLITE_NOINLINE __attribute__((noinline)) 233 233 #elif defined(_MSC_VER) && _MSC_VER>=1310 234 234 # define SQLITE_NOINLINE __declspec(noinline) 235 235 #else 236 236 # define SQLITE_NOINLINE 237 237 #endif 238 238 239 -/* 240 -** The SQLITE_ATOMIC_STATUS_DOWN macro is defined if and only if 241 -** the sqlite3StatusDown() function is threadsafe. 242 -*/ 243 -#if !defined(SQLITE_DISABLE_INTRINSIC) \ 244 - && (GCC_VERSION>=4004000 || CLANG_VERSION>=3000000) 245 -# define SQLITE_ATOMIC_STATUS_DOWN 1 246 -#endif 247 - 248 239 /* 249 240 ** Make sure that the compiler intrinsics we desire are enabled when 250 241 ** compiling with an appropriate version of MSVC unless prevented by 251 242 ** the SQLITE_DISABLE_INTRINSIC define. 252 243 */ 253 244 #if !defined(SQLITE_DISABLE_INTRINSIC) 254 245 # if defined(_MSC_VER) && _MSC_VER>=1400
Changes to src/status.c.
96 96 if( wsdStat.nowValue[op]>wsdStat.mxValue[op] ){ 97 97 wsdStat.mxValue[op] = wsdStat.nowValue[op]; 98 98 } 99 99 } 100 100 void sqlite3StatusDown(int op, int N){ 101 101 wsdStatInit; 102 102 assert( N>=0 ); 103 - assert( op>=0 && op<ArraySize(wsdStat.nowValue) ); 104 -#if !defined(SQLITE_DISABLE_INTRINSIC) \ 105 - && (GCC_VERSION>=4004000 || CLANG_VERSION>=3000000) 106 - (void)__sync_fetch_and_sub(&wsdStat.nowValue[op], N); 107 -#else 108 103 assert( op>=0 && op<ArraySize(statMutex) ); 109 104 assert( sqlite3_mutex_held(statMutex[op] ? sqlite3Pcache1Mutex() 110 105 : sqlite3MallocMutex()) ); 106 + assert( op>=0 && op<ArraySize(wsdStat.nowValue) ); 111 107 wsdStat.nowValue[op] -= N; 112 -#endif 113 108 } 114 109 115 110 /* 116 111 ** Adjust the highwater mark if necessary. 117 112 ** The caller must hold the appropriate mutex. 118 113 */ 119 114 void sqlite3StatusHighwater(int op, int X){