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For the Lemon-generated parser, add a new action type SHIFTREDUCE and use it

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to further compress the parser tables and improve parser performance.

FossilOrigin-Name: 531c3974b3d586c1989cde905b2fb4681239a570
This commit is contained in:
drh
2015-09-07 18:23:37 +00:00
parent 7e698e9d71
commit 3bd48ab213
8 changed files with 252 additions and 156 deletions
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src/lempar.c
+63 -35
View File
@@ -56,15 +56,19 @@
** ParseARG_PDECL A parameter declaration for the %extra_argument
** ParseARG_STORE Code to store %extra_argument into yypParser
** ParseARG_FETCH Code to extract %extra_argument from yypParser
** YYNSTATE the combined number of states.
** YYNRULE the number of rules in the grammar
** YYERRORSYMBOL is the code number of the error symbol. If not
** defined, then do no error processing.
** YYNSTATE the combined number of states.
** YYNRULE the number of rules in the grammar
** YY_MAX_SHIFT Maximum value for shift actions
** YY_MIN_SHIFTREDUCE Minimum value for shift-reduce actions
** YY_MAX_SHIFTREDUCE Maximum value for shift-reduce actions
** YY_MIN_REDUCE Maximum value for reduce actions
** YY_ERROR_ACTION The yy_action[] code for syntax error
** YY_ACCEPT_ACTION The yy_action[] code for accept
** YY_NO_ACTION The yy_action[] code for no-op
*/
%%
#define YY_NO_ACTION (YYNSTATE+YYNRULE+2)
#define YY_ACCEPT_ACTION (YYNSTATE+YYNRULE+1)
#define YY_ERROR_ACTION (YYNSTATE+YYNRULE)
/* The yyzerominor constant is used to initialize instances of
** YYMINORTYPE objects to zero. */
@@ -91,16 +95,20 @@ static const YYMINORTYPE yyzerominor = { 0 };
** Suppose the action integer is N. Then the action is determined as
** follows
**
** 0 <= N < YYNSTATE Shift N. That is, push the lookahead
** 0 <= N <= YY_MAX_SHIFT Shift N. That is, push the lookahead
** token onto the stack and goto state N.
**
** YYNSTATE <= N < YYNSTATE+YYNRULE Reduce by rule N-YYNSTATE.
** N between YY_MIN_SHIFTREDUCE Shift to an arbitrary state then
** and YY_MAX_SHIFTREDUCE reduce by rule N-YY_MIN_SHIFTREDUCE.
**
** N == YYNSTATE+YYNRULE A syntax error has occurred.
** N between YY_MIN_REDUCE Reduce by rule N-YY_MIN_REDUCE
** and YY_MAX_REDUCE
** N == YY_ERROR_ACTION A syntax error has occurred.
**
** N == YYNSTATE+YYNRULE+1 The parser accepts its input.
** N == YY_ACCEPT_ACTION The parser accepts its input.
**
** N == YYNSTATE+YYNRULE+2 No such action. Denotes unused
** N == YY_NO_ACTION No such action. Denotes unused
** slots in the yy_action[] table.
**
** The action table is constructed as a single large table named yy_action[].
@@ -499,9 +507,9 @@ static void yyStackOverflow(yyParser *yypParser, YYMINORTYPE *yypMinor){
}
/*
** Perform a shift action.
** Perform a shift action. Return the number of errors.
*/
static void yy_shift(
static int yy_shift(
yyParser *yypParser, /* The parser to be shifted */
int yyNewState, /* The new state to shift in */
int yyMajor, /* The major token to shift in */
@@ -517,14 +525,14 @@ static void yy_shift(
#if YYSTACKDEPTH>0
if( yypParser->yyidx>=YYSTACKDEPTH ){
yyStackOverflow(yypParser, yypMinor);
return;
return 1;
}
#else
if( yypParser->yyidx>=yypParser->yystksz ){
yyGrowStack(yypParser);
if( yypParser->yyidx>=yypParser->yystksz ){
yyStackOverflow(yypParser, yypMinor);
return;
return 1;
}
}
#endif
@@ -535,13 +543,18 @@ static void yy_shift(
#ifndef NDEBUG
if( yyTraceFILE && yypParser->yyidx>0 ){
int i;
fprintf(yyTraceFILE,"%sShift %d\n",yyTracePrompt,yyNewState);
fprintf(yyTraceFILE,"%sStack:",yyTracePrompt);
for(i=1; i<=yypParser->yyidx; i++)
fprintf(yyTraceFILE," %s",yyTokenName[yypParser->yystack[i].major]);
fprintf(yyTraceFILE,"\n");
if( yyNewState<YYNSTATE ){
fprintf(yyTraceFILE,"%sShift %d\n",yyTracePrompt,yyNewState);
fprintf(yyTraceFILE,"%sStack:",yyTracePrompt);
for(i=1; i<=yypParser->yyidx; i++)
fprintf(yyTraceFILE," %s",yyTokenName[yypParser->yystack[i].major]);
fprintf(yyTraceFILE,"\n");
}else{
fprintf(yyTraceFILE,"%sShift *\n",yyTracePrompt);
}
}
#endif
return 0;
}
/* The following table contains information about every rule that
@@ -574,8 +587,9 @@ static void yy_reduce(
#ifndef NDEBUG
if( yyTraceFILE && yyruleno>=0
&& yyruleno<(int)(sizeof(yyRuleName)/sizeof(yyRuleName[0])) ){
fprintf(yyTraceFILE, "%sReduce [%s].\n", yyTracePrompt,
yyRuleName[yyruleno]);
yysize = yyRuleInfo[yyruleno].nrhs;
fprintf(yyTraceFILE, "%sReduce [%s] -> state %d.\n", yyTracePrompt,
yyRuleName[yyruleno], yymsp[-yysize].stateno);
}
#endif /* NDEBUG */
@@ -613,9 +627,8 @@ static void yy_reduce(
yysize = yyRuleInfo[yyruleno].nrhs;
yypParser->yyidx -= yysize;
yyact = yy_find_reduce_action(yymsp[-yysize].stateno,(YYCODETYPE)yygoto);
if( yyact < YYNSTATE ){
#ifdef NDEBUG
/* If we are not debugging and the reduce action popped at least
if( yyact <= YY_MAX_SHIFTREDUCE ){
/* If the reduce action popped at least
** one element off the stack, then we can push the new element back
** onto the stack here, and skip the stack overflow test in yy_shift().
** That gives a significant speed improvement. */
@@ -625,13 +638,19 @@ static void yy_reduce(
yymsp->stateno = (YYACTIONTYPE)yyact;
yymsp->major = (YYCODETYPE)yygoto;
yymsp->minor = yygotominor;
}else
#ifndef NDEBUG
if( yyTraceFILE ){
fprintf(yyTraceFILE,"%sShift %d\n",yyTracePrompt,yyact);
}
#endif
{
yy_shift(yypParser,yyact,yygoto,&yygotominor);
}else{
if( yy_shift(yypParser,yyact,yygoto,&yygotominor) ) yyact = 0;
}
if( yyact>=YY_MIN_SHIFTREDUCE ){
yy_reduce(yypParser, yyact - YY_MIN_SHIFTREDUCE);
}
}else{
assert( yyact == YYNSTATE + YYNRULE + 1 );
assert( yyact == YY_ACCEPT_ACTION );
yy_accept(yypParser);
}
}
@@ -755,12 +774,16 @@ void Parse(
do{
yyact = yy_find_shift_action(yypParser,(YYCODETYPE)yymajor);
if( yyact<YYNSTATE ){
yy_shift(yypParser,yyact,yymajor,&yyminorunion);
yypParser->yyerrcnt--;
yymajor = YYNOCODE;
}else if( yyact < YYNSTATE + YYNRULE ){
yy_reduce(yypParser,yyact-YYNSTATE);
if( yyact <= YY_MAX_SHIFTREDUCE ){
if( yy_shift(yypParser,yyact,yymajor,&yyminorunion)==0 ){
yypParser->yyerrcnt--;
yymajor = YYNOCODE;
if( yyact > YY_MAX_SHIFT ){
yy_reduce(yypParser, yyact-YY_MIN_SHIFTREDUCE);
}
}
}else if( yyact <= YY_MAX_REDUCE ){
yy_reduce(yypParser,yyact-YY_MIN_REDUCE);
}else{
assert( yyact == YY_ERROR_ACTION );
#ifdef YYERRORSYMBOL
@@ -810,7 +833,7 @@ void Parse(
yymx != YYERRORSYMBOL &&
(yyact = yy_find_reduce_action(
yypParser->yystack[yypParser->yyidx].stateno,
YYERRORSYMBOL)) >= YYNSTATE
YYERRORSYMBOL)) >= YY_MIN_REDUCE
){
yy_pop_parser_stack(yypParser);
}
@@ -860,5 +883,10 @@ void Parse(
#endif
}
}while( yymajor!=YYNOCODE && yypParser->yyidx>=0 );
#ifdef SQLITE_DEBUG
if( yyTraceFILE ){
fprintf(yyTraceFILE,"%sReturn\n",yyTracePrompt);
}
#endif
return;
}
src/parse.y
+1 -1
View File
@@ -587,7 +587,7 @@ from(A) ::= FROM seltablist(X). {
//
stl_prefix(A) ::= seltablist(X) joinop(Y). {
A = X;
if( ALWAYS(A && A->nSrc>0) ) A->a[A->nSrc-1].fg.jointype = (u8)Y;
if( A && A->nSrc>0 ) A->a[A->nSrc-1].fg.jointype = (u8)Y;
}
stl_prefix(A) ::= . {A = 0;}
seltablist(A) ::= stl_prefix(X) nm(Y) dbnm(D) as(Z) indexed_opt(I)
src/tokenize.c
+2 -1
View File
@@ -403,6 +403,7 @@ int sqlite3RunParser(Parse *pParse, const char *zSql, char **pzErrMsg){
pParse->zTail = zSql;
i = 0;
assert( pzErrMsg!=0 );
/* sqlite3ParserTrace(stdout, "parser: "); */
pEngine = sqlite3ParserAlloc(sqlite3Malloc);
if( pEngine==0 ){
db->mallocFailed = 1;
@@ -458,12 +459,12 @@ abort_parse:
assert( zSql[i]==0 );
if( lastTokenParsed!=TK_SEMI ){
sqlite3Parser(pEngine, TK_SEMI, pParse->sLastToken, pParse);
pParse->zTail = &zSql[i];
}
if( pParse->rc==SQLITE_OK && db->mallocFailed==0 ){
sqlite3Parser(pEngine, 0, pParse->sLastToken, pParse);
}
}
pParse->zTail = &zSql[i];
#ifdef YYTRACKMAXSTACKDEPTH
sqlite3_mutex_enter(sqlite3MallocMutex());
sqlite3StatusSet(SQLITE_STATUS_PARSER_STACK,