Rework the logic that factors constant expressions out of inner loops, making

it both simpler and faster.

FossilOrigin-Name: 8dc5c76c766828d7c28090bec30ff48227e7b140

manifest

@@ -1,5 +1,5 @@
-C Adjust\sthe\scommand-line\sshell\sEXPLAIN\sindentation\slogic\sto\shandle\sthe\nsecond\sloop\sof\san\sUPDATE\sthat\sreads\sout\sa\sRowSet.
-D 2013-11-14T23:59:33.676
+C Rework\sthe\slogic\sthat\sfactors\sconstant\sexpressions\sout\sof\sinner\sloops,\smaking\nit\sboth\ssimpler\sand\sfaster.
+D 2013-11-15T01:10:18.507
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 8a07bebafbfda0eb67728f4bd15a36201662d1a1
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -163,19 +163,19 @@ F src/alter.c 2af0330bb1b601af7a7789bf7229675fd772a083
 F src/analyze.c 581d5c18ce89c6f45d4dca65914d0de5b4dad41f
 F src/attach.c 0a17c9364895316ca4f52d06a97a72c0af1ae8b3
 F src/auth.c 523da7fb4979469955d822ff9298352d6b31de34
-F src/backup.c 2f1987981139bd2f6d8c728d64bf09fb387443c3
+F src/backup.c 1809a7caa2504233bdddd12f5018422421789537
 F src/bitvec.c 19a4ba637bd85f8f63fc8c9bae5ade9fb05ec1cb
 F src/btmutex.c 976f45a12e37293e32cae0281b15a21d48a8aaa7
 F src/btree.c 260dedc13119e6fb7930380bd3d294b98362bf5a
 F src/btree.h bfe0e8c5759b4ec77b0d18390064a6ef3cdffaaf
 F src/btreeInt.h f038e818bfadf75afbd09819ed93c26a333d39e0
-F src/build.c 2baeed38bdaa9f1199f101c63db41fdcc4b39ba5
+F src/build.c 5b744617019f6011ee35a88fe046f3fdf6f85c53
 F src/callback.c f99a8957ba2adf369645fac0db09ad8adcf1caa2
 F src/complete.c dc1d136c0feee03c2f7550bafc0d29075e36deac
 F src/ctime.c ea4b7f3623a0fcb1146e7f245d7410033e86859c
 F src/date.c 593c744b2623971e45affd0bde347631bdfa4625
 F src/delete.c ddb92f44595366c4817e576b5f11cad5a915c3ef
-F src/expr.c e7bbe3c6916e141f27a28655d3cf325b817695e4
+F src/expr.c b54ac7b5a77cf2967b4194aba95005544e8b705e
 F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
 F src/fkey.c 78364daed38e26269c53ddb94c515bceac1063c6
 F src/func.c 96caa9dfd1febf9a4b720de4c43ccfb392a52b73
@@ -214,7 +214,7 @@ F src/pcache.c f8043b433a57aba85384a531e3937a804432a346
 F src/pcache.h a5e4f5d9f5d592051d91212c5949517971ae6222
 F src/pcache1.c a467393909a4ed7ca9de066d85ba5c5b04a5be63
 F src/pragma.c c8d70c47ec8d8ba93575d92e34d30ddff8e9b517
-F src/prepare.c fa6988589f39af8504a61731614cd4f6ae71554f
+F src/prepare.c 359d1a1e9c9bd4488e4dd3a1aaaf2d2ebb9bb768
 F src/printf.c da9119eb31a187a4b99f60aa4a225141c0ebb74b
 F src/random.c 0b2dbc37fdfbfa6bd455b091dfcef5bdb32dba68
 F src/resolve.c fc4673cc49b116e51e7f12de074c0acf8f2388f9
@@ -224,7 +224,7 @@ F src/shell.c 65a259d538b283e190708b43ece0d596563097f8
 F src/sqlite.h.in 4dedcab5b32358bf7a596badffe7363be1f1a82d
 F src/sqlite3.rc 11094cc6a157a028b301a9f06b3d03089ea37c3e
 F src/sqlite3ext.h 886f5a34de171002ad46fae8c36a7d8051c190fc
-F src/sqliteInt.h 2ec1d71220307fa5ee85a918a6240cf0b4635b0e
+F src/sqliteInt.h c5dfd52fcc677725c750b1570b090f70a5cb60ec
 F src/sqliteLimit.h 164b0e6749d31e0daa1a4589a169d31c0dec7b3d
 F src/status.c 7ac05a5c7017d0b9f0b4bcd701228b784f987158
 F src/table.c 2cd62736f845d82200acfa1287e33feb3c15d62e
@@ -275,7 +275,7 @@ F src/test_vfs.c e72f555ef7a59080f898fcf1a233deb9eb704ea9
 F src/test_vfstrace.c 34b544e80ba7fb77be15395a609c669df2e660a2
 F src/test_wsd.c 41cadfd9d97fe8e3e4e44f61a4a8ccd6f7ca8fe9
 F src/tokenize.c ec4c1a62b890bf1dbcdb966399e140b904c700a4
-F src/trigger.c 53d6b5d50b3b23d4fcd0a36504feb5cff9aed716
+F src/trigger.c d84e1f3669e9a217731a14a9d472b1c7b87c87ba
 F src/update.c 3de7e657b98ac67338d775c114a4068faf732402
 F src/utf.c 6fc6c88d50448c469c5c196acf21617a24f90269
 F src/util.c 2fa6c821d28bbdbeec1b2a7b091a281c9ef8f918
@@ -285,15 +285,15 @@ F src/vdbe.h c06f0813f853566457ce9cfb1a4a4bc39a5da644
 F src/vdbeInt.h 62eb680327011f3a4b0336642b0ca9d6ecc6eb91
 F src/vdbeapi.c 93a22a9ba2abe292d5c2cf304d7eb2e894dde0ed
 F src/vdbeaux.c dd0f6ab9dc159911facfc0a7a2164af44779bdda
-F src/vdbeblob.c ff60adf2953e0ffc1d59541b3101c9886b03a3de
+F src/vdbeblob.c d883398f7260725147dbf5b40c2b61332aee47f9
 F src/vdbemem.c cc529bbf4f13e4e181bdb446bf6e6962ab030b4b
 F src/vdbesort.c 9d83601f9d6243fe70dd0169a2820c5ddfd48147
 F src/vdbetrace.c e7ec40e1999ff3c6414424365d5941178966dcbc
-F src/vtab.c 5a423b042eb1402ef77697d03d6a67378d97bc8d
+F src/vtab.c 21b932841e51ebd7d075e2d0ad1415dce8d2d5fd
 F src/wal.c 7dc3966ef98b74422267e7e6e46e07ff6c6eb1b4
 F src/wal.h df01efe09c5cb8c8e391ff1715cca294f89668a4
 F src/walker.c e9e593d5bb798c3e67fc3893dfe7055c9e7d8d74
-F src/where.c 9d0b21b65b3d1c9f923b5c6bd0ba250dcd16b645
+F src/where.c 9bff77c96e40bf472050bee6b2f7db8ed8e4402d
 F src/whereInt.h 96a75c61f1d2b9d4a8e4bb17d89deb0cf7cba358
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
 F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
@@ -1139,7 +1139,10 @@ F tool/vdbe-compress.tcl f12c884766bd14277f4fcedcae07078011717381
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh d1a6de74685f360ab718efda6265994b99bbea01
 F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff
-P 10d59226382adcb8016fc2d927e5a0c0b36f3980
-R e492370754f541158ba25713cf44bfcb
+P ea141a9b87dbb5fa1402bf7f6e36e89cc9de3cb3
+R ea4290df34dfa387f06721fb8b8fabb6
+T *branch * expr-codegen-enhancement
+T *sym-expr-codegen-enhancement *
+T -sym-trunk *
 U drh
-Z 035eb0414986ea339898609e92b31744
+Z 42026cbf90dc1d9e1d914e786ac618c6

manifest.uuid

@@ -1 +1 @@
-ea141a9b87dbb5fa1402bf7f6e36e89cc9de3cb3
+8dc5c76c766828d7c28090bec30ff48227e7b140

src/backup.c

@@ -96,6 +96,7 @@ static Btree *findBtree(sqlite3 *pErrorDb, sqlite3 *pDb, const char *zDb){
         rc = SQLITE_ERROR;
       }
       sqlite3DbFree(pErrorDb, pParse->zErrMsg);
+      sqlite3ParserReset(pParse);
       sqlite3StackFree(pErrorDb, pParse);
     }
     if( rc ){

src/build.c

@@ -150,7 +150,7 @@ void sqlite3FinishCoding(Parse *pParse){
     */
     if( pParse->cookieGoto>0 ){
       yDbMask mask;
-      int iDb;
+      int iDb, i, addr;
       sqlite3VdbeJumpHere(v, pParse->cookieGoto-1);
       for(iDb=0, mask=1; iDb<db->nDb; mask<<=1, iDb++){
         if( (mask & pParse->cookieMask)==0 ) continue;
@@ -164,14 +164,11 @@ void sqlite3FinishCoding(Parse *pParse){
         }
       }
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-      {
-        int i;
-        for(i=0; i<pParse->nVtabLock; i++){
-          char *vtab = (char *)sqlite3GetVTable(db, pParse->apVtabLock[i]);
-          sqlite3VdbeAddOp4(v, OP_VBegin, 0, 0, 0, vtab, P4_VTAB);
-        }
-        pParse->nVtabLock = 0;
+      for(i=0; i<pParse->nVtabLock; i++){
+        char *vtab = (char *)sqlite3GetVTable(db, pParse->apVtabLock[i]);
+        sqlite3VdbeAddOp4(v, OP_VBegin, 0, 0, 0, vtab, P4_VTAB);
       }
+      pParse->nVtabLock = 0;
 #endif
 
       /* Once all the cookies have been verified and transactions opened, 
@@ -184,8 +181,18 @@ void sqlite3FinishCoding(Parse *pParse){
       */
       sqlite3AutoincrementBegin(pParse);
 
+      /* Code constant expressions that where factored out of inner loops */
+      addr = pParse->cookieGoto;
+      if( pParse->pConstExpr ){
+        ExprList *pEL = pParse->pConstExpr;
+        pParse->cookieGoto = 0;
+        for(i=0; i<pEL->nExpr; i++){
+          sqlite3ExprCode(pParse, pEL->a[i].pExpr, pEL->a[i].iAlias);
+        }
+      }
+
       /* Finally, jump back to the beginning of the executable code. */
-      sqlite3VdbeAddOp2(v, OP_Goto, 0, pParse->cookieGoto);
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
     }
   }
 

src/expr.c

@@ -2989,15 +2989,42 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
 ** If the register is a temporary register that can be deallocated,
 ** then write its number into *pReg.  If the result register is not
 ** a temporary, then set *pReg to zero.
+**
+** If pExpr is a constant, then this routine might generate this
+** code to fill the register in the initialization section of the
+** VDBE program, in order to factor it out of the evaluation loop.
 */
 int sqlite3ExprCodeTemp(Parse *pParse, Expr *pExpr, int *pReg){
-  int r1 = sqlite3GetTempReg(pParse);
-  int r2 = sqlite3ExprCodeTarget(pParse, pExpr, r1);
-  if( r2==r1 ){
-    *pReg = r1;
+  int r2;
+  pExpr = sqlite3ExprSkipCollate(pExpr);
+  if( pParse->cookieGoto>0
+   && pParse->nMem<32768
+   && pExpr->op!=TK_REGISTER
+   && sqlite3ExprIsConstantNotJoin(pExpr)
+  ){
+    ExprList *p = pParse->pConstExpr;
+    int i;
+    *pReg  = 0;
+    if( p ){
+      for(i=0; i<p->nExpr; i++){
+        if( sqlite3ExprCompare(p->a[i].pExpr, pExpr, -1)==0 ){
+          return p->a[i].iAlias;
+        }
+      }
+    }
+    p = sqlite3ExprListAppend(pParse, p, sqlite3ExprDup(pParse->db, pExpr, 0));
+    pParse->pConstExpr = p;
+    r2 = ++pParse->nMem;
+    if( p ) p->a[p->nExpr-1].iAlias = r2;
   }else{
-    sqlite3ReleaseTempReg(pParse, r1);
-    *pReg = 0;
+    int r1 = sqlite3GetTempReg(pParse);
+    r2 = sqlite3ExprCodeTarget(pParse, pExpr, r1);
+    if( r2==r1 ){
+      *pReg = r1;
+    }else{
+      sqlite3ReleaseTempReg(pParse, r1);
+      *pReg = 0;
+    }
   }
   return r2;
 }
@@ -3328,140 +3355,6 @@ void sqlite3ExplainExprList(Vdbe *pOut, ExprList *pList){
 }
 #endif /* SQLITE_DEBUG */
 
-/*
-** Return TRUE if pExpr is an constant expression that is appropriate
-** for factoring out of a loop.  Appropriate expressions are:
-**
-**    *  Any expression that evaluates to two or more opcodes.
-**
-**    *  Any OP_Integer, OP_Real, OP_String, OP_Blob, OP_Null, 
-**       or OP_Variable that does not need to be placed in a 
-**       specific register.
-**
-** There is no point in factoring out single-instruction constant
-** expressions that need to be placed in a particular register.  
-** We could factor them out, but then we would end up adding an
-** OP_SCopy instruction to move the value into the correct register
-** later.  We might as well just use the original instruction and
-** avoid the OP_SCopy.
-*/
-static int isAppropriateForFactoring(Expr *p){
-  if( !sqlite3ExprIsConstantNotJoin(p) ){
-    return 0;  /* Only constant expressions are appropriate for factoring */
-  }
-  if( (p->flags & EP_FixedDest)==0 ){
-    return 1;  /* Any constant without a fixed destination is appropriate */
-  }
-  while( p->op==TK_UPLUS ) p = p->pLeft;
-  switch( p->op ){
-#ifndef SQLITE_OMIT_BLOB_LITERAL
-    case TK_BLOB:
-#endif
-    case TK_VARIABLE:
-    case TK_INTEGER:
-    case TK_FLOAT:
-    case TK_NULL:
-    case TK_STRING: {
-      testcase( p->op==TK_BLOB );
-      testcase( p->op==TK_VARIABLE );
-      testcase( p->op==TK_INTEGER );
-      testcase( p->op==TK_FLOAT );
-      testcase( p->op==TK_NULL );
-      testcase( p->op==TK_STRING );
-      /* Single-instruction constants with a fixed destination are
-      ** better done in-line.  If we factor them, they will just end
-      ** up generating an OP_SCopy to move the value to the destination
-      ** register. */
-      return 0;
-    }
-    case TK_UMINUS: {
-      if( p->pLeft->op==TK_FLOAT || p->pLeft->op==TK_INTEGER ){
-        return 0;
-      }
-      break;
-    }
-    default: {
-      break;
-    }
-  }
-  return 1;
-}
-
-/*
-** If pExpr is a constant expression that is appropriate for
-** factoring out of a loop, then evaluate the expression
-** into a register and convert the expression into a TK_REGISTER
-** expression.
-*/
-static int evalConstExpr(Walker *pWalker, Expr *pExpr){
-  Parse *pParse = pWalker->pParse;
-  switch( pExpr->op ){
-    case TK_IN:
-    case TK_REGISTER: {
-      return WRC_Prune;
-    }
-    case TK_COLLATE: {
-      return WRC_Continue;
-    }
-    case TK_FUNCTION:
-    case TK_AGG_FUNCTION:
-    case TK_CONST_FUNC: {
-      /* The arguments to a function have a fixed destination.
-      ** Mark them this way to avoid generated unneeded OP_SCopy
-      ** instructions. 
-      */
-      ExprList *pList = pExpr->x.pList;
-      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
-      if( pList ){
-        int i = pList->nExpr;
-        struct ExprList_item *pItem = pList->a;
-        for(; i>0; i--, pItem++){
-          if( ALWAYS(pItem->pExpr) ) pItem->pExpr->flags |= EP_FixedDest;
-        }
-      }
-      break;
-    }
-  }
-  if( isAppropriateForFactoring(pExpr) ){
-    int r1 = ++pParse->nMem;
-    int r2 = sqlite3ExprCodeTarget(pParse, pExpr, r1);
-    /* If r2!=r1, it means that register r1 is never used.  That is harmless
-    ** but suboptimal, so we want to know about the situation to fix it.
-    ** Hence the following assert: */
-    assert( r2==r1 );
-    exprToRegister(pExpr, r2);
-    return WRC_Prune;
-  }
-  return WRC_Continue;
-}
-
-/*
-** Preevaluate constant subexpressions within pExpr and store the
-** results in registers.  Modify pExpr so that the constant subexpresions
-** are TK_REGISTER opcodes that refer to the precomputed values.
-**
-** This routine is a no-op if the jump to the cookie-check code has
-** already occur.  Since the cookie-check jump is generated prior to
-** any other serious processing, this check ensures that there is no
-** way to accidently bypass the constant initializations.
-**
-** This routine is also a no-op if the SQLITE_FactorOutConst optimization
-** is disabled via the sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS)
-** interface.  This allows test logic to verify that the same answer is
-** obtained for queries regardless of whether or not constants are
-** precomputed into registers or if they are inserted in-line.
-*/
-void sqlite3ExprCodeConstants(Parse *pParse, Expr *pExpr){
-  Walker w;
-  if( pParse->cookieGoto ) return;
-  if( OptimizationDisabled(pParse->db, SQLITE_FactorOutConst) ) return;
-  memset(&w, 0, sizeof(w));
-  w.xExprCallback = evalConstExpr;
-  w.pParse = pParse;
-  sqlite3WalkExpr(&w, pExpr);
-}
-
-
 /*
 ** Generate code that pushes the value of every element of the given
 ** expression list into a sequence of registers beginning at target.
@@ -3863,7 +3756,7 @@ int sqlite3ExprCompare(Expr *pA, Expr *pB, int iTab){
   if( pA->iColumn!=pB->iColumn ) return 2;
   if( pA->iTable!=pB->iTable 
    && pA->op!=TK_REGISTER
-   && (pA->iTable!=iTab || NEVER(pB->iTable>=0)) ) return 2;
+   && (pA->iTable!=iTab || pB->iTable>=0) ) return 2;
   if( ExprHasProperty(pA, EP_IntValue) ){
     if( !ExprHasProperty(pB, EP_IntValue) || pA->u.iValue!=pB->u.iValue ){
       return 2;

src/prepare.c

@@ -524,6 +524,13 @@ int sqlite3SchemaToIndex(sqlite3 *db, Schema *pSchema){
   return i;
 }
 
+/*
+** Free all memory allocations in the pParse object
+*/
+void sqlite3ParserReset(Parse *pParse){
+  if( pParse ) sqlite3ExprListDelete(pParse->db, pParse->pConstExpr);
+}
+
 /*
 ** Compile the UTF-8 encoded SQL statement zSql into a statement handle.
 */
@@ -681,6 +688,7 @@ static int sqlite3Prepare(
 
 end_prepare:
 
+  sqlite3ParserReset(pParse);
   sqlite3StackFree(db, pParse);
   rc = sqlite3ApiExit(db, rc);
   assert( (rc&db->errMask)==rc );

src/sqliteInt.h

@@ -2278,6 +2278,7 @@ struct Parse {
     int iReg;             /* Reg with value of this column. 0 means none. */
     int lru;              /* Least recently used entry has the smallest value */
   } aColCache[SQLITE_N_COLCACHE];  /* One for each column cache entry */
+  ExprList *pConstExpr;/* Constant expressions */
   yDbMask writeMask;   /* Start a write transaction on these databases */
   yDbMask cookieMask;  /* Bitmask of schema verified databases */
   int cookieGoto;      /* Address of OP_Goto to cookie verifier subroutine */
@@ -2891,7 +2892,6 @@ int sqlite3ExprCode(Parse*, Expr*, int);
 int sqlite3ExprCodeTemp(Parse*, Expr*, int*);
 int sqlite3ExprCodeTarget(Parse*, Expr*, int);
 int sqlite3ExprCodeAndCache(Parse*, Expr*, int);
-void sqlite3ExprCodeConstants(Parse*, Expr*);
 int sqlite3ExprCodeExprList(Parse*, ExprList*, int, int);
 void sqlite3ExprIfTrue(Parse*, Expr*, int, int);
 void sqlite3ExprIfFalse(Parse*, Expr*, int, int);
@@ -3259,6 +3259,7 @@ void sqlite3InvalidFunction(sqlite3_context*,int,sqlite3_value**);
 sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context*);
 int sqlite3VdbeParameterIndex(Vdbe*, const char*, int);
 int sqlite3TransferBindings(sqlite3_stmt *, sqlite3_stmt *);
+void sqlite3ParserReset(Parse*);
 int sqlite3Reprepare(Vdbe*);
 void sqlite3ExprListCheckLength(Parse*, ExprList*, const char*);
 CollSeq *sqlite3BinaryCompareCollSeq(Parse *, Expr *, Expr *);

src/trigger.c

@@ -924,6 +924,7 @@ static TriggerPrg *codeRowTrigger(
 
   assert( !pSubParse->pAinc       && !pSubParse->pZombieTab );
   assert( !pSubParse->pTriggerPrg && !pSubParse->nMaxArg );
+  sqlite3ParserReset(pSubParse);
   sqlite3StackFree(db, pSubParse);
 
   return pPrg;

src/vdbeblob.c

@@ -328,6 +328,7 @@ blob_open_out:
   }
   sqlite3Error(db, rc, (zErr ? "%s" : 0), zErr);
   sqlite3DbFree(db, zErr);
+  sqlite3ParserReset(pParse);
   sqlite3StackFree(db, pParse);
   rc = sqlite3ApiExit(db, rc);
   sqlite3_mutex_leave(db->mutex);

src/vtab.c

@@ -738,6 +738,7 @@ int sqlite3_declare_vtab(sqlite3 *db, const char *zCreateTable){
       sqlite3VdbeFinalize(pParse->pVdbe);
     }
     sqlite3DeleteTable(db, pParse->pNewTable);
+    sqlite3ParserReset(pParse);
     sqlite3StackFree(db, pParse);
   }
 

src/where.c

@@ -5426,7 +5426,6 @@ WhereInfo *sqlite3WhereBegin(
   */
   initMaskSet(pMaskSet);
   whereClauseInit(&pWInfo->sWC, pWInfo);
-  sqlite3ExprCodeConstants(pParse, pWhere);
   whereSplit(&pWInfo->sWC, pWhere, TK_AND);
   sqlite3CodeVerifySchema(pParse, -1); /* Insert the cookie verifier Goto */