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

OP_InitCoroutine and OP_EndCoroutine.

FossilOrigin-Name: 1ec0e9dd4b26d9f597adc8e062317d4866c5a6a6

1 files changed, 13 insertions, 31 deletions

diff --git a/src/insert.c b/src/insert.c
index edf277876..c7e60a478 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -373,16 +373,13 @@ void sqlite3AutoincrementEnd(Parse *pParse){
 **           yield X
 **         end loop
 **         cleanup after the SELECT
-**         R <- undefined (signals EOF)
-**         yield X
-**         halt-error
+**         end co-routine R
 **      B:
 **
 ** To use this subroutine, the caller generates code as follows:
 **
 **         [ Co-routine generated by this subroutine, shown above ]
-**      S: yield X
-**         if R==undefined goto E
+**      S: yield X, at EOF goto E
 **         if skip this row, goto C
 **         if terminate loop, goto E
 **         deal with this row
@@ -399,18 +396,14 @@ int sqlite3CodeCoroutine(Parse *pParse, Select *pSelect, SelectDest *pDest){
   regYield = ++pParse->nMem;
   v = sqlite3GetVdbe(pParse);
   addrTop = sqlite3VdbeCurrentAddr(v);
-  sqlite3VdbeAddOp2(v, OP_Integer, addrTop+1, regYield); /* X <- A */
-  VdbeComment((v, "Co-routine entry point"));
+  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_Undef, pDest->iSdst);     /* Signal EOF */
-  sqlite3VdbeAddOp1(v, OP_Yield, regYield);         /* yield X */
-  sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_INTERNAL, OE_Abort);
-  VdbeComment((v, "End of coroutine"));
+  sqlite3VdbeAddOp1(v, OP_EndCoroutine, regYield);
   sqlite3VdbeJumpHere(v, j1);                             /* label B: */
   return rc;
 }
@@ -487,12 +480,9 @@ static int xferOptimization(
 **           yield X
 **         end loop
 **         cleanup after the SELECT
-**         R <- undefined (signals EOF)
-**         yield X
-**         goto A
+**         end-coroutine X
 **      B: open write cursor to <table> and its indices
-**      C: yield X
-**         if R=undefined goto D
+**      C: yield X, at EOF goto D
 **         insert the select result into <table> from R..R+n
 **         goto C
 **      D: cleanup
@@ -511,12 +501,9 @@ static int xferOptimization(
 **           yield X
 **         end loop
 **         cleanup after the SELECT
-**         R <- undefined (signals EOF)
-**         yield X
-**         halt-error
+**         end co-routine R
 **      B: open temp table
-**      L: yield X
-**         if R=undefined goto M
+**      L: yield X, at EOF goto M
 **         insert row from R..R+n into temp table
 **         goto L
 **      M: open write cursor to <table> and its indices
@@ -701,8 +688,7 @@ void sqlite3Insert(
       ** here is from the 4th template:
       **
       **      B: open temp table
-      **      L: yield X
-      **         if R=undefined goto M
+      **      L: yield X, goto M at EOF
       **         insert row from R..R+n into temp table
       **         goto L
       **      M: ...
@@ -710,19 +696,17 @@ void sqlite3Insert(
       int regRec;          /* Register to hold packed record */
       int regTempRowid;    /* Register to hold temp table ROWID */
       int addrTop;         /* Label "L" */
-      int addrIf;          /* Address of jump to M */
 
       srcTab = pParse->nTab++;
       regRec = sqlite3GetTempReg(pParse);
       regTempRowid = sqlite3GetTempReg(pParse);
       sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
       addrTop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
-      addrIf = sqlite3VdbeAddOp1(v, OP_IsUndef, regFromSelect);
       sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
       sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
       sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
       sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);
-      sqlite3VdbeJumpHere(v, addrIf);
+      sqlite3VdbeJumpHere(v, addrTop);
       sqlite3ReleaseTempReg(pParse, regRec);
       sqlite3ReleaseTempReg(pParse, regTempRowid);
     }
@@ -834,7 +818,7 @@ void sqlite3Insert(
     /* This block codes the top of loop only.  The complete loop is the
     ** following pseudocode (template 4):
     **
-    **         rewind temp table
+    **         rewind temp table, if empty goto D
     **      C: loop over rows of intermediate table
     **           transfer values form intermediate table into <table>
     **         end loop
@@ -846,14 +830,12 @@ void sqlite3Insert(
     /* This block codes the top of loop only.  The complete loop is the
     ** following pseudocode (template 3):
     **
-    **      C: yield X
-    **         if R=undefined goto D
+    **      C: yield X, at EOF goto D
     **         insert the select result into <table> from R..R+n
     **         goto C
     **      D: ...
     */
-    addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
-    addrInsTop = sqlite3VdbeAddOp1(v, OP_IsUndef, dest.iSdst);
+    addrInsTop = addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
   }
 
   /* Allocate registers for holding the rowid of the new row,