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Overview
Comment: | More agressive use of /*A-overwrites-X*/ in the parser. Fix an off-by-one error in parser stack overflow detection. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | parser-performance |
Files: | files | file ages | folders |
SHA1: |
417e777701bbf4bd67626d4ca3bc2c5d |
User & Date: | drh 2016-02-17 12:34:03.961 |
Context
2016-02-17
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13:24 | Enhance Lemon to generate more compact and efficient code for yy_reduce(). Update the main SQL grammar to take advantage of the new capabilities. (check-in: 53fd040c98 user: drh tags: trunk) | |
12:34 | More agressive use of /*A-overwrites-X*/ in the parser. Fix an off-by-one error in parser stack overflow detection. (Closed-Leaf check-in: 417e777701 user: drh tags: parser-performance) | |
04:33 | Enhance Lemon so that if reduce code contains a comment of the form "/*A-overwrites-X*/" then a LHS label A is allowed to overwrite the RHS label X. (check-in: 5cfe9545d4 user: drh tags: parser-performance) | |
Changes
Changes to src/parse.y.
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298 299 300 301 302 303 304 | v.pExpr = sqlite3PExpr(pParse, TK_UMINUS, X.pExpr, 0, 0); v.zStart = A.z; v.zEnd = X.zEnd; sqlite3AddDefaultValue(pParse,&v); } ccons ::= DEFAULT id(X). { ExprSpan v; | | | 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 | v.pExpr = sqlite3PExpr(pParse, TK_UMINUS, X.pExpr, 0, 0); v.zStart = A.z; v.zEnd = X.zEnd; sqlite3AddDefaultValue(pParse,&v); } ccons ::= DEFAULT id(X). { ExprSpan v; spanExpr(&v, pParse, TK_STRING, X); sqlite3AddDefaultValue(pParse,&v); } // In addition to the type name, we also care about the primary key and // UNIQUE constraints. // ccons ::= NULL onconf. |
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486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 | %type multiselect_op {int} multiselect_op(A) ::= UNION(OP). {A = @OP; /*A-overwrites-OP*/} multiselect_op(A) ::= UNION ALL. {A = TK_ALL;} multiselect_op(A) ::= EXCEPT|INTERSECT(OP). {A = @OP; /*A-overwrites-OP*/} %endif SQLITE_OMIT_COMPOUND_SELECT oneselect(A) ::= SELECT(S) distinct(D) selcollist(W) from(X) where_opt(Y) groupby_opt(P) having_opt(Q) orderby_opt(Z) limit_opt(L). { A = sqlite3SelectNew(pParse,W,X,Y,P,Q,Z,D,L.pLimit,L.pOffset); #if SELECTTRACE_ENABLED /* Populate the Select.zSelName[] string that is used to help with ** query planner debugging, to differentiate between multiple Select ** objects in a complex query. ** ** If the SELECT keyword is immediately followed by a C-style comment ** then extract the first few alphanumeric characters from within that ** comment to be the zSelName value. Otherwise, the label is #N where ** is an integer that is incremented with each SELECT statement seen. */ if( A!=0 ){ | > > > | | 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 | %type multiselect_op {int} multiselect_op(A) ::= UNION(OP). {A = @OP; /*A-overwrites-OP*/} multiselect_op(A) ::= UNION ALL. {A = TK_ALL;} multiselect_op(A) ::= EXCEPT|INTERSECT(OP). {A = @OP; /*A-overwrites-OP*/} %endif SQLITE_OMIT_COMPOUND_SELECT oneselect(A) ::= SELECT(S) distinct(D) selcollist(W) from(X) where_opt(Y) groupby_opt(P) having_opt(Q) orderby_opt(Z) limit_opt(L). { #if SELECTTRACE_ENABLED Token s = S; /*A-overwrites-S*/ #endif A = sqlite3SelectNew(pParse,W,X,Y,P,Q,Z,D,L.pLimit,L.pOffset); #if SELECTTRACE_ENABLED /* Populate the Select.zSelName[] string that is used to help with ** query planner debugging, to differentiate between multiple Select ** objects in a complex query. ** ** If the SELECT keyword is immediately followed by a C-style comment ** then extract the first few alphanumeric characters from within that ** comment to be the zSelName value. Otherwise, the label is #N where ** is an integer that is incremented with each SELECT statement seen. */ if( A!=0 ){ const char *z = s.z+6; int i; sqlite3_snprintf(sizeof(A->zSelName), A->zSelName, "#%d", ++pParse->nSelect); while( z[0]==' ' ) z++; if( z[0]=='/' && z[1]=='*' ){ z += 2; while( z[0]==' ' ) z++; |
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848 849 850 851 852 853 854 | pOut->zEnd = &pEnd->z[pEnd->n]; } /* Construct a new Expr object from a single identifier. Use the ** new Expr to populate pOut. Set the span of pOut to be the identifier ** that created the expression. */ | | | | | | > | | | | | > | > | | | | < > < | 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 | pOut->zEnd = &pEnd->z[pEnd->n]; } /* Construct a new Expr object from a single identifier. Use the ** new Expr to populate pOut. Set the span of pOut to be the identifier ** that created the expression. */ static void spanExpr(ExprSpan *pOut, Parse *pParse, int op, Token t){ pOut->pExpr = sqlite3PExpr(pParse, op, 0, 0, &t); pOut->zStart = t.z; pOut->zEnd = &t.z[t.n]; } } expr(A) ::= term(A). expr(A) ::= LP(B) expr(X) RP(E). {spanSet(&A,&B,&E); /*A-overwrites-B*/ A.pExpr = X.pExpr;} term(A) ::= NULL(X). {spanExpr(&A,pParse,@X,X);/*A-overwrites-X*/} expr(A) ::= id(X). {spanExpr(&A,pParse,TK_ID,X); /*A-overwrites-X*/} expr(A) ::= JOIN_KW(X). {spanExpr(&A,pParse,TK_ID,X); /*A-overwrites-X*/} expr(A) ::= nm(X) DOT nm(Y). { Expr *temp1 = sqlite3PExpr(pParse, TK_ID, 0, 0, &X); Expr *temp2 = sqlite3PExpr(pParse, TK_ID, 0, 0, &Y); spanSet(&A,&X,&Y); /*A-overwrites-X*/ A.pExpr = sqlite3PExpr(pParse, TK_DOT, temp1, temp2, 0); } expr(A) ::= nm(X) DOT nm(Y) DOT nm(Z). { Expr *temp1 = sqlite3PExpr(pParse, TK_ID, 0, 0, &X); Expr *temp2 = sqlite3PExpr(pParse, TK_ID, 0, 0, &Y); Expr *temp3 = sqlite3PExpr(pParse, TK_ID, 0, 0, &Z); Expr *temp4 = sqlite3PExpr(pParse, TK_DOT, temp2, temp3, 0); spanSet(&A,&X,&Z); /*A-overwrites-X*/ A.pExpr = sqlite3PExpr(pParse, TK_DOT, temp1, temp4, 0); } term(A) ::= INTEGER|FLOAT|BLOB(X). {spanExpr(&A,pParse,@X,X);/*A-overwrites-X*/} term(A) ::= STRING(X). {spanExpr(&A,pParse,@X,X);/*A-overwrites-X*/} expr(A) ::= VARIABLE(X). { Token t = X; /*A-overwrites-X*/ if( t.n>=2 && t.z[0]=='#' && sqlite3Isdigit(t.z[1]) ){ /* When doing a nested parse, one can include terms in an expression ** that look like this: #1 #2 ... These terms refer to registers ** in the virtual machine. #N is the N-th register. */ spanSet(&A, &t, &t); if( pParse->nested==0 ){ sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", &t); A.pExpr = 0; }else{ A.pExpr = sqlite3PExpr(pParse, TK_REGISTER, 0, 0, &t); if( A.pExpr ) sqlite3GetInt32(&t.z[1], &A.pExpr->iTable); } }else{ spanExpr(&A, pParse, TK_VARIABLE, t); sqlite3ExprAssignVarNumber(pParse, A.pExpr); } } expr(A) ::= expr(A) COLLATE ids(C). { A.pExpr = sqlite3ExprAddCollateToken(pParse, A.pExpr, &C, 1); A.zEnd = &C.z[C.n]; } %ifndef SQLITE_OMIT_CAST expr(A) ::= CAST(X) LP expr(E) AS typetoken(T) RP(Y). { spanSet(&A,&X,&Y); /*A-overwrites-X*/ A.pExpr = sqlite3PExpr(pParse, TK_CAST, E.pExpr, 0, &T); } %endif SQLITE_OMIT_CAST expr(A) ::= id(X) LP distinct(D) exprlist(Y) RP(E). { if( Y && Y->nExpr>pParse->db->aLimit[SQLITE_LIMIT_FUNCTION_ARG] ){ sqlite3ErrorMsg(pParse, "too many arguments on function %T", &X); } A.pExpr = sqlite3ExprFunction(pParse, Y, &X); |
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1037 1038 1039 1040 1041 1042 1043 | static void spanUnaryPrefix( ExprSpan *pOut, /* Write the new expression node here */ Parse *pParse, /* Parsing context to record errors */ int op, /* The operator */ ExprSpan *pOperand, /* The operand */ Token *pPreOp /* The operand token for setting the span */ ){ | < > | > | > | | | 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 | static void spanUnaryPrefix( ExprSpan *pOut, /* Write the new expression node here */ Parse *pParse, /* Parsing context to record errors */ int op, /* The operator */ ExprSpan *pOperand, /* The operand */ Token *pPreOp /* The operand token for setting the span */ ){ pOut->zStart = pPreOp->z; pOut->pExpr = sqlite3PExpr(pParse, op, pOperand->pExpr, 0, 0); pOut->zEnd = pOperand->zEnd; } } expr(A) ::= NOT(B) expr(X). {spanUnaryPrefix(&A,pParse,@B,&X,&B);/*A-overwrites-B*/} expr(A) ::= BITNOT(B) expr(X). {spanUnaryPrefix(&A,pParse,@B,&X,&B);/*A-overwrites-B*/} expr(A) ::= MINUS(B) expr(X). [BITNOT] {spanUnaryPrefix(&A,pParse,TK_UMINUS,&X,&B);/*A-overwrites-B*/} expr(A) ::= PLUS(B) expr(X). [BITNOT] {spanUnaryPrefix(&A,pParse,TK_UPLUS,&X,&B);/*A-overwrites-B*/} %type between_op {int} between_op(A) ::= BETWEEN. {A = 0;} between_op(A) ::= NOT BETWEEN. {A = 1;} expr(A) ::= expr(A) between_op(N) expr(X) AND expr(Y). [BETWEEN] { ExprList *pList = sqlite3ExprListAppend(pParse,0, X.pExpr); pList = sqlite3ExprListAppend(pParse,pList, Y.pExpr); |
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1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 | sqlite3ExprListDelete(pParse->db, Y); } exprNot(pParse, N, &A); } A.zEnd = &E.z[E.n]; } expr(A) ::= LP(B) select(X) RP(E). { A.pExpr = sqlite3PExpr(pParse, TK_SELECT, 0, 0, 0); if( A.pExpr ){ A.pExpr->x.pSelect = X; ExprSetProperty(A.pExpr, EP_xIsSelect|EP_Subquery); sqlite3ExprSetHeightAndFlags(pParse, A.pExpr); }else{ sqlite3SelectDelete(pParse->db, X); } | > < < | 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 | sqlite3ExprListDelete(pParse->db, Y); } exprNot(pParse, N, &A); } A.zEnd = &E.z[E.n]; } expr(A) ::= LP(B) select(X) RP(E). { spanSet(&A,&B,&E); /*A-overwrites-B*/ A.pExpr = sqlite3PExpr(pParse, TK_SELECT, 0, 0, 0); if( A.pExpr ){ A.pExpr->x.pSelect = X; ExprSetProperty(A.pExpr, EP_xIsSelect|EP_Subquery); sqlite3ExprSetHeightAndFlags(pParse, A.pExpr); }else{ sqlite3SelectDelete(pParse->db, X); } } expr(A) ::= expr(A) in_op(N) LP select(Y) RP(E). [IN] { A.pExpr = sqlite3PExpr(pParse, TK_IN, A.pExpr, 0, 0); if( A.pExpr ){ A.pExpr->x.pSelect = Y; ExprSetProperty(A.pExpr, EP_xIsSelect|EP_Subquery); sqlite3ExprSetHeightAndFlags(pParse, A.pExpr); |
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1160 1161 1162 1163 1164 1165 1166 | }else{ sqlite3SrcListDelete(pParse->db, pSrc); } exprNot(pParse, N, &A); A.zEnd = Z.z ? &Z.z[Z.n] : &Y.z[Y.n]; } expr(A) ::= EXISTS(B) LP select(Y) RP(E). { | > > | < < > < < | 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 | }else{ sqlite3SrcListDelete(pParse->db, pSrc); } exprNot(pParse, N, &A); A.zEnd = Z.z ? &Z.z[Z.n] : &Y.z[Y.n]; } expr(A) ::= EXISTS(B) LP select(Y) RP(E). { Expr *p; spanSet(&A,&B,&E); /*A-overwrites-B*/ p = A.pExpr = sqlite3PExpr(pParse, TK_EXISTS, 0, 0, 0); if( p ){ p->x.pSelect = Y; ExprSetProperty(p, EP_xIsSelect|EP_Subquery); sqlite3ExprSetHeightAndFlags(pParse, p); }else{ sqlite3SelectDelete(pParse->db, Y); } } %endif SQLITE_OMIT_SUBQUERY /* CASE expressions */ expr(A) ::= CASE(C) case_operand(X) case_exprlist(Y) case_else(Z) END(E). { spanSet(&A,&C,&E); /*A-overwrites-C*/ A.pExpr = sqlite3PExpr(pParse, TK_CASE, X, 0, 0); if( A.pExpr ){ A.pExpr->x.pList = Z ? sqlite3ExprListAppend(pParse,Y,Z) : Y; sqlite3ExprSetHeightAndFlags(pParse, A.pExpr); }else{ sqlite3ExprListDelete(pParse->db, Y); sqlite3ExprDelete(pParse->db, Z); } } %type case_exprlist {ExprList*} %destructor case_exprlist {sqlite3ExprListDelete(pParse->db, $$);} case_exprlist(A) ::= case_exprlist(A) WHEN expr(Y) THEN expr(Z). { A = sqlite3ExprListAppend(pParse,A, Y.pExpr); A = sqlite3ExprListAppend(pParse,A, Z.pExpr); } |
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1411 1412 1413 1414 1415 1416 1417 | %type trigger_cmd {TriggerStep*} %destructor trigger_cmd {sqlite3DeleteTriggerStep(pParse->db, $$);} // UPDATE trigger_cmd(A) ::= UPDATE orconf(R) trnm(X) tridxby SET setlist(Y) where_opt(Z). | | | | | | 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 | %type trigger_cmd {TriggerStep*} %destructor trigger_cmd {sqlite3DeleteTriggerStep(pParse->db, $$);} // UPDATE trigger_cmd(A) ::= UPDATE orconf(R) trnm(X) tridxby SET setlist(Y) where_opt(Z). {A = sqlite3TriggerUpdateStep(pParse->db, &X, Y, Z, R);} // INSERT trigger_cmd(A) ::= insert_cmd(R) INTO trnm(X) idlist_opt(F) select(S). {A = sqlite3TriggerInsertStep(pParse->db, &X, F, S, R);/*A-overwrites-R*/} // DELETE trigger_cmd(A) ::= DELETE FROM trnm(X) tridxby where_opt(Y). {A = sqlite3TriggerDeleteStep(pParse->db, &X, Y);} // SELECT trigger_cmd(A) ::= select(X). {A = sqlite3TriggerSelectStep(pParse->db, X); /*A-overwrites-X*/} // The special RAISE expression that may occur in trigger programs expr(A) ::= RAISE(X) LP IGNORE RP(Y). { spanSet(&A,&X,&Y); /*A-overwrites-X*/ A.pExpr = sqlite3PExpr(pParse, TK_RAISE, 0, 0, 0); if( A.pExpr ){ A.pExpr->affinity = OE_Ignore; |
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Changes to tool/lemon.c.
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3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 | ** Return 1 if the expanded code requires that "yylhsminor" local variable ** to be defined. */ PRIVATE int translate_code(struct lemon *lemp, struct rule *rp){ char *cp, *xp; int i; int rc = 0; /* True if yylhsminor is used */ const char *zSkip = 0; /* The zOvwrt comment within rp->code, or NULL */ char lhsused = 0; /* True if the LHS element has been used */ char lhsdirect; /* True if LHS writes directly into stack */ char used[MAXRHS]; /* True for each RHS element which is used */ char zLhs[50]; /* Convert the LHS symbol into this string */ char zOvwrt[900]; /* Comment that to allow LHS to overwrite RHS */ | > | 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 | ** Return 1 if the expanded code requires that "yylhsminor" local variable ** to be defined. */ PRIVATE int translate_code(struct lemon *lemp, struct rule *rp){ char *cp, *xp; int i; int rc = 0; /* True if yylhsminor is used */ int dontUseRhs0 = 0; /* If true, use of left-most RHS label is illegal */ const char *zSkip = 0; /* The zOvwrt comment within rp->code, or NULL */ char lhsused = 0; /* True if the LHS element has been used */ char lhsdirect; /* True if LHS writes directly into stack */ char used[MAXRHS]; /* True for each RHS element which is used */ char zLhs[50]; /* Convert the LHS symbol into this string */ char zOvwrt[900]; /* Comment that to allow LHS to overwrite RHS */ |
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3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 | append_str(0,0,0,0); /* This const cast is wrong but harmless, if we're careful. */ for(cp=(char *)rp->code; *cp; cp++){ if( cp==zSkip ){ append_str(zOvwrt,0,0,0); cp += lemonStrlen(zOvwrt)-1; continue; } if( ISALPHA(*cp) && (cp==rp->code || (!ISALNUM(cp[-1]) && cp[-1]!='_')) ){ char saved; for(xp= &cp[1]; ISALNUM(*xp) || *xp=='_'; xp++); saved = *xp; *xp = 0; if( rp->lhsalias && strcmp(cp,rp->lhsalias)==0 ){ append_str(zLhs,0,0,0); cp = xp; lhsused = 1; }else{ for(i=0; i<rp->nrhs; i++){ if( rp->rhsalias[i] && strcmp(cp,rp->rhsalias[i])==0 ){ | > > > > > > | | 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580 | append_str(0,0,0,0); /* This const cast is wrong but harmless, if we're careful. */ for(cp=(char *)rp->code; *cp; cp++){ if( cp==zSkip ){ append_str(zOvwrt,0,0,0); cp += lemonStrlen(zOvwrt)-1; dontUseRhs0 = 1; continue; } if( ISALPHA(*cp) && (cp==rp->code || (!ISALNUM(cp[-1]) && cp[-1]!='_')) ){ char saved; for(xp= &cp[1]; ISALNUM(*xp) || *xp=='_'; xp++); saved = *xp; *xp = 0; if( rp->lhsalias && strcmp(cp,rp->lhsalias)==0 ){ append_str(zLhs,0,0,0); cp = xp; lhsused = 1; }else{ for(i=0; i<rp->nrhs; i++){ if( rp->rhsalias[i] && strcmp(cp,rp->rhsalias[i])==0 ){ if( i==0 && dontUseRhs0 ){ ErrorMsg(lemp->filename,rp->ruleline, "Label %s used after '%s'.", rp->rhsalias[0], zOvwrt); lemp->errorcnt++; }else if( cp!=rp->code && cp[-1]=='@' ){ /* If the argument is of the form @X then substituted ** the token number of X, not the value of X */ append_str("yymsp[%d].major",-1,i-rp->nrhs+1,0); }else{ struct symbol *sp = rp->rhs[i]; int dtnum; if( sp->type==MULTITERMINAL ){ |
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Changes to tool/lempar.c.
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633 634 635 636 637 638 639 | if( yyRuleInfo[yyruleno].nrhs==0 ){ #ifdef YYTRACKMAXSTACKDEPTH if( yypParser->yyidx>yypParser->yyidxMax ){ yypParser->yyidxMax = yypParser->yyidx; } #endif #if YYSTACKDEPTH>0 | | | | | 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 | if( yyRuleInfo[yyruleno].nrhs==0 ){ #ifdef YYTRACKMAXSTACKDEPTH if( yypParser->yyidx>yypParser->yyidxMax ){ yypParser->yyidxMax = yypParser->yyidx; } #endif #if YYSTACKDEPTH>0 if( yypParser->yyidx>=YYSTACKDEPTH-1 ){ yyStackOverflow(yypParser); return; } #else if( yypParser->yyidx>=yypParser->yystksz-1 ){ yyGrowStack(yypParser); if( yypParser->yyidx>=yypParser->yystksz-1 ){ yyStackOverflow(yypParser); return; } } #endif } |
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