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Overview
Comment:Change the OP_InitCoroutine instruction to jump over the co-routine implementation.
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Timelines: family | ancestors | descendants | both | coroutine-refactor
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SHA1:a522f364a6b8ca6f69c353b30609a2166f6e94cf
User & Date: drh 2014-02-07 19:18:10
Context
2014-02-07
22:21
Add opcodes OP_InitCoroutine and OP_EndCoroutine. Use these to remove the need for separate boolean registers to record when a co-routine has finished. check-in: 5a88b6a7 user: drh tags: trunk
19:18
Change the OP_InitCoroutine instruction to jump over the co-routine implementation. Closed-Leaf check-in: a522f364 user: drh tags: coroutine-refactor
18:27
Get rid of the OP_Undef and OP_IsUndef opcodes in favor of higher-level OP_InitCoroutine and OP_EndCoroutine. check-in: 1ec0e9dd user: drh tags: coroutine-refactor
Changes
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Changes to src/insert.c.

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**         deal with this row
**      C: goto S
**      E:
*/
int sqlite3CodeCoroutine(Parse *pParse, Select *pSelect, SelectDest *pDest){
  int regYield;       /* Register holding co-routine entry-point */
  int addrTop;        /* Top of the co-routine */
  int j1;             /* Jump instruction */
  int rc;             /* Result code */
  Vdbe *v;            /* VDBE under construction */

  regYield = ++pParse->nMem;
  v = sqlite3GetVdbe(pParse);
  addrTop = sqlite3VdbeCurrentAddr(v);
  sqlite3VdbeAddOp2(v, OP_InitCoroutine, regYield, addrTop+2);
  sqlite3SelectDestInit(pDest, SRT_Coroutine, regYield);
  j1 = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
  rc = sqlite3Select(pParse, pSelect, pDest);
  assert( pParse->nErr==0 || rc );
  if( pParse->db->mallocFailed && rc==SQLITE_OK ) rc = SQLITE_NOMEM;
  if( rc ) return rc;
  sqlite3VdbeAddOp1(v, OP_EndCoroutine, regYield);
  sqlite3VdbeJumpHere(v, j1);                             /* label B: */
  return rc;
}



/* Forward declaration */
static int xferOptimization(







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**         deal with this row
**      C: goto S
**      E:
*/
int sqlite3CodeCoroutine(Parse *pParse, Select *pSelect, SelectDest *pDest){
  int regYield;       /* Register holding co-routine entry-point */
  int addrTop;        /* Top of the co-routine */

  int rc;             /* Result code */
  Vdbe *v;            /* VDBE under construction */

  regYield = ++pParse->nMem;
  v = sqlite3GetVdbe(pParse);
  addrTop = sqlite3VdbeCurrentAddr(v) + 1;
  sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, addrTop);
  sqlite3SelectDestInit(pDest, SRT_Coroutine, regYield);

  rc = sqlite3Select(pParse, pSelect, pDest);
  assert( pParse->nErr==0 || rc );
  if( pParse->db->mallocFailed && rc==SQLITE_OK ) rc = SQLITE_NOMEM;
  if( rc ) return rc;
  sqlite3VdbeAddOp1(v, OP_EndCoroutine, regYield);
  sqlite3VdbeJumpHere(v, addrTop - 1);                       /* label B: */
  return rc;
}



/* Forward declaration */
static int xferOptimization(

Changes to src/select.c.

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  regAddrA = ++pParse->nMem;
  regAddrB = ++pParse->nMem;
  regOutA = ++pParse->nMem;
  regOutB = ++pParse->nMem;
  sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
  sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);

  /* Jump past the various subroutines and coroutines to the main
  ** merge loop
  */
  j1 = sqlite3VdbeAddOp0(v, OP_Goto);


  /* Generate a coroutine to evaluate the SELECT statement to the
  ** left of the compound operator - the "A" select.
  */
  VdbeNoopComment((v, "coroutine for left SELECT"));
  addrSelectA = sqlite3VdbeCurrentAddr(v);


  pPrior->iLimit = regLimitA;
  explainSetInteger(iSub1, pParse->iNextSelectId);
  sqlite3Select(pParse, pPrior, &destA);
  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);


  savedLimit = p->iLimit;
  savedOffset = p->iOffset;
  p->iLimit = regLimitB;
  p->iOffset = 0;  
  explainSetInteger(iSub2, pParse->iNextSelectId);
  sqlite3Select(pParse, p, &destB);
  p->iLimit = savedLimit;
................................................................................
  }
  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_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
  */
  sqlite3VdbeResolveLabel(v, labelCmpr);
  sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY);







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  regAddrA = ++pParse->nMem;
  regAddrB = ++pParse->nMem;
  regOutA = ++pParse->nMem;
  regOutB = ++pParse->nMem;
  sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
  sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);







  /* Generate a coroutine to evaluate the SELECT statement to the
  ** left of the compound operator - the "A" select.
  */

  addrSelectA = sqlite3VdbeCurrentAddr(v) + 1;
  j1 = sqlite3VdbeAddOp3(v, OP_InitCoroutine, regAddrA, 0, addrSelectA);
  VdbeComment((v, "left SELECT"));
  pPrior->iLimit = regLimitA;
  explainSetInteger(iSub1, pParse->iNextSelectId);
  sqlite3Select(pParse, pPrior, &destA);
  sqlite3VdbeAddOp1(v, OP_EndCoroutine, regAddrA);
  sqlite3VdbeJumpHere(v, j1);

  /* Generate a coroutine to evaluate the SELECT statement on 
  ** the right - the "B" select
  */

  addrSelectB = sqlite3VdbeCurrentAddr(v) + 1;
  j1 = sqlite3VdbeAddOp3(v, OP_InitCoroutine, regAddrB, 0, addrSelectB);
  VdbeComment((v, "right SELECT"));
  savedLimit = p->iLimit;
  savedOffset = p->iOffset;
  p->iLimit = regLimitB;
  p->iOffset = 0;  
  explainSetInteger(iSub2, pParse->iNextSelectId);
  sqlite3Select(pParse, p, &destB);
  p->iLimit = savedLimit;
................................................................................
  }
  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_Yield, regAddrA, addrEofA_noB);
  sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, addrEofB);

  /* Implement the main merge loop
  */
  sqlite3VdbeResolveLabel(v, labelCmpr);
  sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY);

Changes to src/vdbe.c.

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  pIn1 = &aMem[pOp->p1];
  assert( pIn1->flags==MEM_Int );
  pc = (int)pIn1->u.i;
  pIn1->flags = MEM_Undefined;
  break;
}

/* Opcode: InitCoroutine P1 P2 * * *
**
** Identify the co-routine at address P2 using the register P1
** as its return address.  Run this opcode prior to the first 
** OP_Yield to invoke the co-routine.



*/
case OP_InitCoroutine: {     /* jump */
  assert( pOp->p1>0 );
  assert( pOp->p1<=(p->nMem-p->nCursor) );


  pOut = &aMem[pOp->p1];
  memAboutToChange(p, pOut);
  VdbeMemRelease(pOut);

  pOut->u.i = pOp->p2 - 1;
  pOut->flags = MEM_Int;

  break;
}

/* Opcode:  EndCoroutine P1 * * * *
**
** The instruction at the address in register P1 is an OP_Yield.
** Jump to the P2 parameter of that OP_Yield.







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  pIn1 = &aMem[pOp->p1];
  assert( pIn1->flags==MEM_Int );
  pc = (int)pIn1->u.i;
  pIn1->flags = MEM_Undefined;
  break;
}

/* Opcode: InitCoroutine P1 P2 P3 * *
**
** Set up register P1 so that it will OP_Yield to the co-routine
** located at address P3.
**
** If P2!=0 then the co-routine implementation immediately follows
** this opcode.  So jump over the co-routine implementation to
** address P2.
*/
case OP_InitCoroutine: {     /* jump */

  assert( pOp->p1>0 &&  pOp->p1<=(p->nMem-p->nCursor) );
  assert( pOp->p2>=0 && pOp->p2<p->nOp );
  assert( pOp->p3>=0 && pOp->p3<p->nOp );
  pOut = &aMem[pOp->p1];


  assert( !VdbeMemDynamic(pOut) );
  pOut->u.i = pOp->p3 - 1;
  pOut->flags = MEM_Int;
  if( pOp->p2 ) pc = pOp->p2 - 1;
  break;
}

/* Opcode:  EndCoroutine P1 * * * *
**
** The instruction at the address in register P1 is an OP_Yield.
** Jump to the P2 parameter of that OP_Yield.

Changes to src/vdbeInt.h.

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double sqlite3VdbeRealValue(Mem*);
void sqlite3VdbeIntegerAffinity(Mem*);
int sqlite3VdbeMemRealify(Mem*);
int sqlite3VdbeMemNumerify(Mem*);
int sqlite3VdbeMemFromBtree(BtCursor*,u32,u32,int,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
void sqlite3VdbeMemReleaseExternal(Mem *p);
#define VdbeMemRelease(X)  \
  if((X)->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame)) \

    sqlite3VdbeMemReleaseExternal(X);
int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
const char *sqlite3OpcodeName(int);
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeCloseStatement(Vdbe *, int);
void sqlite3VdbeFrameDelete(VdbeFrame*);
int sqlite3VdbeFrameRestore(VdbeFrame *);
void sqlite3VdbeMemStoreType(Mem *pMem);







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double sqlite3VdbeRealValue(Mem*);
void sqlite3VdbeIntegerAffinity(Mem*);
int sqlite3VdbeMemRealify(Mem*);
int sqlite3VdbeMemNumerify(Mem*);
int sqlite3VdbeMemFromBtree(BtCursor*,u32,u32,int,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
void sqlite3VdbeMemReleaseExternal(Mem *p);
#define VdbeMemDynamic(X)  \
  (((X)->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame))!=0)
#define VdbeMemRelease(X)  \
  if( VdbeMemDynamic(X) ) sqlite3VdbeMemReleaseExternal(X);
int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
const char *sqlite3OpcodeName(int);
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeCloseStatement(Vdbe *, int);
void sqlite3VdbeFrameDelete(VdbeFrame*);
int sqlite3VdbeFrameRestore(VdbeFrame *);
void sqlite3VdbeMemStoreType(Mem *pMem);

Changes to src/where.c.

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    sqlite3VdbeAddOp2(v, OP_Integer, 0, pLevel->iLeftJoin);
    VdbeComment((v, "init LEFT JOIN no-match flag"));
  }

  /* Special case of a FROM clause subquery implemented as a co-routine */
  if( pTabItem->viaCoroutine ){
    int regYield = pTabItem->regReturn;
    sqlite3VdbeAddOp2(v, OP_InitCoroutine, regYield, pTabItem->addrFillSub);
    pLevel->p2 =  sqlite3VdbeAddOp2(v, OP_Yield, regYield, addrBrk);
    VdbeComment((v, "next row of co-routine %s", pTabItem->pTab->zName));
    pLevel->op = OP_Goto;
  }else

#ifndef SQLITE_OMIT_VIRTUALTABLE
  if(  (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){







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    sqlite3VdbeAddOp2(v, OP_Integer, 0, pLevel->iLeftJoin);
    VdbeComment((v, "init LEFT JOIN no-match flag"));
  }

  /* Special case of a FROM clause subquery implemented as a co-routine */
  if( pTabItem->viaCoroutine ){
    int regYield = pTabItem->regReturn;
    sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pTabItem->addrFillSub);
    pLevel->p2 =  sqlite3VdbeAddOp2(v, OP_Yield, regYield, addrBrk);
    VdbeComment((v, "next row of co-routine %s", pTabItem->pTab->zName));
    pLevel->op = OP_Goto;
  }else

#ifndef SQLITE_OMIT_VIRTUALTABLE
  if(  (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){