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Get rid of the OP_Undef and OP_IsUndef opcodes in favor of higher-level

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OP_InitCoroutine and OP_EndCoroutine.

FossilOrigin-Name: 1ec0e9dd4b26d9f597adc8e062317d4866c5a6a6
This commit is contained in:
drh
2014-02-07 18:27:53 +00:00
parent a5750cfe01
commit 81cf13ec7b
6 changed files with 97 additions and 123 deletions
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70
src/select.c
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@@ -765,12 +765,8 @@ static void selectInnerLoop(
}
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
/* Send the data to the callback function or to a subroutine. In the
** case of a subroutine, the subroutine itself is responsible for
** popping the data from the stack.
*/
case SRT_Coroutine:
case SRT_Output: {
case SRT_Coroutine: /* Send data to a co-routine */
case SRT_Output: { /* Return the results */
testcase( eDest==SRT_Coroutine );
testcase( eDest==SRT_Output );
if( pOrderBy ){
@@ -2572,9 +2568,7 @@ static int multiSelectOrderBy(
SelectDest destA; /* Destination for coroutine A */
SelectDest destB; /* Destination for coroutine B */
int regAddrA; /* Address register for select-A coroutine */
int regEofA; /* Flag to indicate when select-A is complete */
int regAddrB; /* Address register for select-B coroutine */
int regEofB; /* Flag to indicate when select-B is complete */
int addrSelectA; /* Address of the select-A coroutine */
int addrSelectB; /* Address of the select-B coroutine */
int regOutA; /* Address register for the output-A subroutine */
@@ -2582,6 +2576,7 @@ static int multiSelectOrderBy(
int addrOutA; /* Address of the output-A subroutine */
int addrOutB = 0; /* Address of the output-B subroutine */
int addrEofA; /* Address of the select-A-exhausted subroutine */
int addrEofA_noB; /* Alternate addrEofA if B is uninitialized */
int addrEofB; /* Address of the select-B-exhausted subroutine */
int addrAltB; /* Address of the A<B subroutine */
int addrAeqB; /* Address of the A==B subroutine */
@@ -2718,9 +2713,7 @@ static int multiSelectOrderBy(
p->pOffset = 0;
regAddrA = ++pParse->nMem;
regEofA = ++pParse->nMem;
regAddrB = ++pParse->nMem;
regEofB = ++pParse->nMem;
regOutA = ++pParse->nMem;
regOutB = ++pParse->nMem;
sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
@@ -2730,25 +2723,23 @@ static int multiSelectOrderBy(
** merge loop
*/
j1 = sqlite3VdbeAddOp0(v, OP_Goto);
addrSelectA = sqlite3VdbeCurrentAddr(v);
/* Generate a coroutine to evaluate the SELECT statement to the
** left of the compound operator - the "A" select.
*/
VdbeNoopComment((v, "Begin coroutine for left SELECT"));
VdbeNoopComment((v, "coroutine for left SELECT"));
addrSelectA = sqlite3VdbeCurrentAddr(v);
pPrior->iLimit = regLimitA;
explainSetInteger(iSub1, pParse->iNextSelectId);
sqlite3Select(pParse, pPrior, &destA);
sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofA);
sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
VdbeNoopComment((v, "End coroutine for left SELECT"));
sqlite3VdbeAddOp1(v, OP_EndCoroutine, regAddrA);
/* Generate a coroutine to evaluate the SELECT statement on
** the right - the "B" select
*/
VdbeNoopComment((v, "coroutine for right SELECT"));
addrSelectB = sqlite3VdbeCurrentAddr(v);
VdbeNoopComment((v, "Begin coroutine for right SELECT"));
savedLimit = p->iLimit;
savedOffset = p->iOffset;
p->iLimit = regLimitB;
@@ -2757,9 +2748,7 @@ static int multiSelectOrderBy(
sqlite3Select(pParse, p, &destB);
p->iLimit = savedLimit;
p->iOffset = savedOffset;
sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofB);
sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
VdbeNoopComment((v, "End coroutine for right SELECT"));
sqlite3VdbeAddOp1(v, OP_EndCoroutine, regAddrB);
/* Generate a subroutine that outputs the current row of the A
** select as the next output row of the compound select.
@@ -2783,13 +2772,12 @@ static int multiSelectOrderBy(
/* Generate a subroutine to run when the results from select A
** are exhausted and only data in select B remains.
*/
VdbeNoopComment((v, "eof-A subroutine"));
if( op==TK_EXCEPT || op==TK_INTERSECT ){
addrEofA = sqlite3VdbeAddOp2(v, OP_Goto, 0, labelEnd);
addrEofA_noB = addrEofA = labelEnd;
}else{
addrEofA = sqlite3VdbeAddOp2(v, OP_If, regEofB, labelEnd);
sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
VdbeNoopComment((v, "eof-A subroutine"));
addrEofA = sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
addrEofA_noB = sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, labelEnd);
sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofA);
p->nSelectRow += pPrior->nSelectRow;
}
@@ -2802,9 +2790,8 @@ static int multiSelectOrderBy(
if( p->nSelectRow > pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow;
}else{
VdbeNoopComment((v, "eof-B subroutine"));
addrEofB = sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
addrEofB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, labelEnd);
sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofB);
}
@@ -2812,8 +2799,7 @@ static int multiSelectOrderBy(
*/
VdbeNoopComment((v, "A-lt-B subroutine"));
addrAltB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA);
sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
/* Generate code to handle the case of A==B
@@ -2826,8 +2812,7 @@ static int multiSelectOrderBy(
}else{
VdbeNoopComment((v, "A-eq-B subroutine"));
addrAeqB =
sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA);
sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
}
@@ -2838,19 +2823,16 @@ static int multiSelectOrderBy(
if( op==TK_ALL || op==TK_UNION ){
sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
}
sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);
sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, addrEofB);
sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
/* This code runs once to initialize everything.
*/
sqlite3VdbeJumpHere(v, j1);
sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofA);
sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofB);
sqlite3VdbeAddOp2(v, OP_Gosub, regAddrA, addrSelectA);
sqlite3VdbeAddOp2(v, OP_Gosub, regAddrB, addrSelectB);
sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);
sqlite3VdbeAddOp2(v, OP_InitCoroutine, regAddrA, addrSelectA);
sqlite3VdbeAddOp2(v, OP_InitCoroutine, regAddrB, addrSelectB);
sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA_noB);
sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, addrEofB);
/* Implement the main merge loop
*/
@@ -4559,9 +4541,7 @@ int sqlite3Select(
** set on each invocation.
*/
int addrTop;
int addrEof;
pItem->regReturn = ++pParse->nMem;
addrEof = ++pParse->nMem;
/* Before coding the OP_Goto to jump to the start of the main routine,
** ensure that the jump to the verify-schema routine has already
** been coded. Otherwise, the verify-schema would likely be coded as
@@ -4574,10 +4554,8 @@ int sqlite3Select(
sqlite3VdbeAddOp0(v, OP_Goto);
addrTop = sqlite3VdbeAddOp1(v, OP_OpenPseudo, pItem->iCursor);
sqlite3VdbeChangeP5(v, 1);
VdbeComment((v, "coroutine for %s", pItem->pTab->zName));
VdbeComment((v, "coroutine %s", pItem->pTab->zName));
pItem->addrFillSub = addrTop;
sqlite3VdbeAddOp2(v, OP_Integer, 0, addrEof);
sqlite3VdbeChangeP5(v, 1);
sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->regReturn);
explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
sqlite3Select(pParse, pSub, &dest);
@@ -4585,9 +4563,7 @@ int sqlite3Select(
pItem->viaCoroutine = 1;
sqlite3VdbeChangeP2(v, addrTop, dest.iSdst);
sqlite3VdbeChangeP3(v, addrTop, dest.nSdst);
sqlite3VdbeAddOp2(v, OP_Integer, 1, addrEof);
sqlite3VdbeAddOp1(v, OP_Yield, pItem->regReturn);
VdbeComment((v, "end %s", pItem->pTab->zName));
sqlite3VdbeAddOp1(v, OP_EndCoroutine, pItem->regReturn);
sqlite3VdbeJumpHere(v, addrTop-1);
sqlite3ClearTempRegCache(pParse);
}else{