Simplify the bytecode generation for SQL function calls such that the

OP_Function or OP_PureFunc opcodes are coded directly, rather than using
the intermediate OP_Function0 or OP_PureFunc0 - opcodes that are now removed.

FossilOrigin-Name: 84e02d773d60cffe619104991d21d7f0c68616c0f6bb99686bf54f5306c756d0

6 files changed, 97 insertions, 71 deletions

diff --git a/src/analyze.c b/src/analyze.c
index 6df6e7a6e..2a071ef12 100644
--- a/src/analyze.c
+++ b/src/analyze.c
@@ -916,18 +916,17 @@ static const FuncDef statGetFuncdef = {
   {0}
 };
 
-static void callStatGet(Vdbe *v, int regStat4, int iParam, int regOut){
-  assert( regOut!=regStat4 && regOut!=regStat4+1 );
+static void callStatGet(Parse *pParse, int regStat4, int iParam, int regOut){
 #ifdef SQLITE_ENABLE_STAT4
-  sqlite3VdbeAddOp2(v, OP_Integer, iParam, regStat4+1);
+  sqlite3VdbeAddOp2(pParse->pVdbe, OP_Integer, iParam, regStat4+1);
 #elif SQLITE_DEBUG
   assert( iParam==STAT_GET_STAT1 );
 #else
   UNUSED_PARAMETER( iParam );
 #endif
-  sqlite3VdbeAddOp4(v, OP_Function0, 0, regStat4, regOut,
-                    (char*)&statGetFuncdef, P4_FUNCDEF);
-  sqlite3VdbeChangeP5(v, 1 + IsStat4);
+  assert( regOut!=regStat4 && regOut!=regStat4+1 );
+  sqlite3VdbeAddFunctionCall(pParse, 0, regStat4, regOut, 1+IsStat4,
+                             &statGetFuncdef, 0);
 }
 
 /*
@@ -1095,9 +1094,8 @@ static void analyzeOneTable(
 #endif
     sqlite3VdbeAddOp2(v, OP_Integer, nCol, regStat4+1);
     sqlite3VdbeAddOp2(v, OP_Integer, pIdx->nKeyCol, regStat4+2);
-    sqlite3VdbeAddOp4(v, OP_Function0, 0, regStat4+1, regStat4,
-                     (char*)&statInitFuncdef, P4_FUNCDEF);
-    sqlite3VdbeChangeP5(v, 2+IsStat4);
+    sqlite3VdbeAddFunctionCall(pParse, 0, regStat4+1, regStat4, 2+IsStat4,
+                               &statInitFuncdef, 0);
 
     /* Implementation of the following:
     **
@@ -1192,13 +1190,12 @@ static void analyzeOneTable(
     }
 #endif
     assert( regChng==(regStat4+1) );
-    sqlite3VdbeAddOp4(v, OP_Function0, 1, regStat4, regTemp,
-                     (char*)&statPushFuncdef, P4_FUNCDEF);
-    sqlite3VdbeChangeP5(v, 2+IsStat4);
+    sqlite3VdbeAddFunctionCall(pParse, 1, regStat4, regTemp, 2+IsStat4,
+                               &statPushFuncdef, 0);
     sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, addrNextRow); VdbeCoverage(v);
 
     /* Add the entry to the stat1 table. */
-    callStatGet(v, regStat4, STAT_GET_STAT1, regStat1);
+    callStatGet(pParse, regStat4, STAT_GET_STAT1, regStat1);
     assert( "BBB"[0]==SQLITE_AFF_TEXT );
     sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regTemp, "BBB", 0);
     sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regNewRowid);
@@ -1224,12 +1221,12 @@ static void analyzeOneTable(
       pParse->nMem = MAX(pParse->nMem, regCol+nCol);
 
       addrNext = sqlite3VdbeCurrentAddr(v);
-      callStatGet(v, regStat4, STAT_GET_ROWID, regSampleRowid);
+      callStatGet(pParse, regStat4, STAT_GET_ROWID, regSampleRowid);
       addrIsNull = sqlite3VdbeAddOp1(v, OP_IsNull, regSampleRowid);
       VdbeCoverage(v);
-      callStatGet(v, regStat4, STAT_GET_NEQ, regEq);
-      callStatGet(v, regStat4, STAT_GET_NLT, regLt);
-      callStatGet(v, regStat4, STAT_GET_NDLT, regDLt);
+      callStatGet(pParse, regStat4, STAT_GET_NEQ, regEq);
+      callStatGet(pParse, regStat4, STAT_GET_NLT, regLt);
+      callStatGet(pParse, regStat4, STAT_GET_NDLT, regDLt);
       sqlite3VdbeAddOp4Int(v, seekOp, iTabCur, addrNext, regSampleRowid, 0);
       VdbeCoverage(v);
       for(i=0; i<nCol; i++){
diff --git a/src/attach.c b/src/attach.c
index 1dcb407ed..ca9af483c 100644
--- a/src/attach.c
+++ b/src/attach.c
@@ -401,11 +401,8 @@ static void codeAttach(
 
   assert( v || db->mallocFailed );
   if( v ){
-    sqlite3VdbeAddOp4(v, OP_Function0, 0, regArgs+3-pFunc->nArg, regArgs+3,
-                      (char *)pFunc, P4_FUNCDEF);
-    assert( pFunc->nArg==-1 || (pFunc->nArg&0xff)==pFunc->nArg );
-    sqlite3VdbeChangeP5(v, (u8)(pFunc->nArg));
- 
+    sqlite3VdbeAddFunctionCall(pParse, 0, regArgs+3-pFunc->nArg, regArgs+3,
+                               pFunc->nArg, pFunc, 0);
     /* Code an OP_Expire. For an ATTACH statement, set P1 to true (expire this
     ** statement only). For DETACH, set it to false (expire all existing
     ** statements).
diff --git a/src/expr.c b/src/expr.c
index 7dd557736..36ab7c795 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -4032,9 +4032,8 @@ expr_code_doover:
       }else
 #endif
       {
-        sqlite3VdbeAddOp4(v, pParse->iSelfTab ? OP_PureFunc0 : OP_Function0,
-                          constMask, r1, target, (char*)pDef, P4_FUNCDEF);
-        sqlite3VdbeChangeP5(v, (u8)nFarg);
+        sqlite3VdbeAddFunctionCall(pParse, constMask, r1, target, nFarg,
+                                   pDef, pParse->iSelfTab);
       }
       if( nFarg && constMask==0 ){
         sqlite3ReleaseTempRange(pParse, r1, nFarg);
diff --git a/src/vdbe.c b/src/vdbe.c
index 7c8d2a4ef..dbfa18a5e 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -7442,13 +7442,15 @@ case OP_MaxPgcnt: {            /* out2 */
 }
 #endif
 
-/* Opcode: Function0 P1 P2 P3 P4 P5
+/* Opcode: Function P1 P2 P3 P4 *
 ** Synopsis: r[P3]=func(r[P2@P5])
 **
-** Invoke a user function (P4 is a pointer to a FuncDef object that
-** defines the function) with P5 arguments taken from register P2 and
-** successors.  The result of the function is stored in register P3.
-** Register P3 must not be one of the function inputs.
+** Invoke a user function (P4 is a pointer to an sqlite3_context object that
+** contains a pointer to the function to be run) with arguments taken
+** from register P2 and successors.  The number of arguments is in
+** the sqlite3_context object that P4 points to.
+** The result of the function is stored
+** in register P3.  Register P3 must not be one of the function inputs.
 **
 ** P1 is a 32-bit bitmask indicating whether or not each argument to the 
 ** function was determined to be constant at compile time. If the first
@@ -7457,14 +7459,16 @@ case OP_MaxPgcnt: {            /* out2 */
 ** sqlite3_set_auxdata() API may be safely retained until the next
 ** invocation of this opcode.
 **
-** See also: Function, AggStep, AggFinal
+** See also: AggStep, AggFinal, PureFunc
 */
-/* Opcode: Function P1 P2 P3 P4 P5
+/* Opcode: PureFunc P1 P2 P3 P4 *
 ** Synopsis: r[P3]=func(r[P2@P5])
 **
 ** Invoke a user function (P4 is a pointer to an sqlite3_context object that
-** contains a pointer to the function to be run) with P5 arguments taken
-** from register P2 and successors.  The result of the function is stored
+** contains a pointer to the function to be run) with arguments taken
+** from register P2 and successors.  The number of arguments is in
+** the sqlite3_context object that P4 points to.
+** The result of the function is stored
 ** in register P3.  Register P3 must not be one of the function inputs.
 **
 ** P1 is a 32-bit bitmask indicating whether or not each argument to the 
@@ -7474,40 +7478,16 @@ case OP_MaxPgcnt: {            /* out2 */
 ** sqlite3_set_auxdata() API may be safely retained until the next
 ** invocation of this opcode.
 **
-** SQL functions are initially coded as OP_Function0 with P4 pointing
-** to a FuncDef object.  But on first evaluation, the P4 operand is
-** automatically converted into an sqlite3_context object and the operation
-** changed to this OP_Function opcode.  In this way, the initialization of
-** the sqlite3_context object occurs only once, rather than once for each
-** evaluation of the function.
+** This opcode works exactly like OP_Function.  The only difference is in
+** its name.  This opcode is used in places where the function must be
+** purely non-deterministic.  Some built-in date/time functions can be
+** either determinitic of non-deterministic, depending on their arguments.
+** When those function are used in a non-deterministic way, they will check
+** to see if they were called using OP_PureFunc instead of OP_Function, and
+** if they were, they throw an error.
 **
-** See also: Function0, AggStep, AggFinal
+** See also: AggStep, AggFinal, Function
 */
-case OP_PureFunc0:              /* group */
-case OP_Function0: {            /* group */
-  int n;
-  sqlite3_context *pCtx;
-
-  assert( pOp->p4type==P4_FUNCDEF );
-  n = pOp->p5;
-  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
-  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=(p->nMem+1 - p->nCursor)+1) );
-  assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );
-  pCtx = sqlite3DbMallocRawNN(db, sizeof(*pCtx) + (n-1)*sizeof(sqlite3_value*));
-  if( pCtx==0 ) goto no_mem;
-  pCtx->pOut = 0;
-  pCtx->pFunc = pOp->p4.pFunc;
-  pCtx->iOp = (int)(pOp - aOp);
-  pCtx->pVdbe = p;
-  pCtx->isError = 0;
-  pCtx->argc = n;
-  pOp->p4type = P4_FUNCCTX;
-  pOp->p4.pCtx = pCtx;
-  assert( OP_PureFunc == OP_PureFunc0+2 );
-  assert( OP_Function == OP_Function0+2 );
-  pOp->opcode += 2;
-  /* Fall through into OP_Function */
-}
 case OP_PureFunc:              /* group */
 case OP_Function: {            /* group */
   int i;
@@ -7522,9 +7502,11 @@ case OP_Function: {            /* group */
   ** reinitializes the relavant parts of the sqlite3_context object */
   pOut = &aMem[pOp->p3];
   if( pCtx->pOut != pOut ){
+    pCtx->pVdbe = p;
     pCtx->pOut = pOut;
     for(i=pCtx->argc-1; i>=0; i--) pCtx->argv[i] = &aMem[pOp->p2+i];
   }
+  assert( pCtx->pVdbe==p );
 
   memAboutToChange(p, pOut);
 #ifdef SQLITE_DEBUG
diff --git a/src/vdbe.h b/src/vdbe.h
index b5c2f02de..3214d5bce 100644
--- a/src/vdbe.h
+++ b/src/vdbe.h
@@ -190,6 +190,7 @@ int sqlite3VdbeAddOp3(Vdbe*,int,int,int,int);
 int sqlite3VdbeAddOp4(Vdbe*,int,int,int,int,const char *zP4,int);
 int sqlite3VdbeAddOp4Dup8(Vdbe*,int,int,int,int,const u8*,int);
 int sqlite3VdbeAddOp4Int(Vdbe*,int,int,int,int,int);
+int sqlite3VdbeAddFunctionCall(Parse*,int,int,int,int,const FuncDef*,int);
 void sqlite3VdbeEndCoroutine(Vdbe*,int);
 #if defined(SQLITE_DEBUG) && !defined(SQLITE_TEST_REALLOC_STRESS)
   void sqlite3VdbeVerifyNoMallocRequired(Vdbe *p, int N);
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index c83292fa4..de6575cd5 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -15,6 +15,10 @@
 #include "sqliteInt.h"
 #include "vdbeInt.h"
 
+/* Forward references */
+static void freeEphemeralFunction(sqlite3 *db, FuncDef *pDef);
+static void vdbeFreeOpArray(sqlite3 *, Op *, int);
+
 /*
 ** Create a new virtual database engine.
 */
@@ -329,6 +333,48 @@ int sqlite3VdbeAddOp4(
 }
 
 /*
+** Add an OP_Function or OP_PureFunc opcode.
+**
+** The eCallCtx argument is information (typically taken from Expr.op2)
+** that describes the calling context of the function.  0 means a general
+** function call.  NC_IsCheck means called by a check constraint,
+** NC_IdxExpr means called as part of an index expression.  NC_PartIdx
+** means in the WHERE clause of a partial index.  NC_GenCol means called
+** while computing a generated column value.  0 is the usual case.
+*/
+int sqlite3VdbeAddFunctionCall(
+  Parse *pParse,        /* Parsing context */
+  int p1,               /* Constant argument mask */
+  int p2,               /* First argument register */
+  int p3,               /* Register into which results are written */
+  int nArg,             /* Number of argument */
+  const FuncDef *pFunc, /* The function to be invoked */
+  int eCallCtx          /* Calling context */
+){
+  Vdbe *v = pParse->pVdbe;
+  int nByte;
+  int addr;
+  sqlite3_context *pCtx;
+  assert( v );
+  nByte = sizeof(*pCtx) + (nArg-1)*sizeof(sqlite3_value*);
+  pCtx = sqlite3DbMallocRawNN(pParse->db, nByte);
+  if( pCtx==0 ){
+    assert( pParse->db->mallocFailed );
+    freeEphemeralFunction(pParse->db, (FuncDef*)pFunc);
+    return 0;
+  }
+  pCtx->pOut = 0;
+  pCtx->pFunc = (FuncDef*)pFunc;
+  pCtx->pVdbe = v;
+  pCtx->isError = 0;
+  pCtx->argc = nArg;
+  addr = sqlite3VdbeAddOp4(v, eCallCtx ? OP_PureFunc : OP_Function,
+                           p1, p2, p3, (char*)pCtx, P4_FUNCCTX);
+  pCtx->iOp = addr;
+  return addr;
+}
+
+/*
 ** Add an opcode that includes the p4 value with a P4_INT64 or
 ** P4_REAL type.
 */
@@ -1020,8 +1066,6 @@ static void freeEphemeralFunction(sqlite3 *db, FuncDef *pDef){
   }
 }
 
-static void vdbeFreeOpArray(sqlite3 *, Op *, int);
-
 /*
 ** Delete a P4 value if necessary.
 */
@@ -1031,7 +1075,7 @@ static SQLITE_NOINLINE void freeP4Mem(sqlite3 *db, Mem *p){
 }
 static SQLITE_NOINLINE void freeP4FuncCtx(sqlite3 *db, sqlite3_context *p){
   freeEphemeralFunction(db, p->pFunc);
- sqlite3DbFreeNN(db, p);
+  sqlite3DbFreeNN(db, p);
 }
 static void freeP4(sqlite3 *db, int p4type, void *p4){
   assert( db );
@@ -1537,13 +1581,11 @@ static char *displayP4(Op *pOp, char *zTemp, int nTemp){
       sqlite3_str_appendf(&x, "%s(%d)", pDef->zName, pDef->nArg);
       break;
     }
-#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
     case P4_FUNCCTX: {
       FuncDef *pDef = pOp->p4.pCtx->pFunc;
       sqlite3_str_appendf(&x, "%s(%d)", pDef->zName, pDef->nArg);
       break;
     }
-#endif
     case P4_INT64: {
       sqlite3_str_appendf(&x, "%lld", *pOp->p4.pI64);
       break;
@@ -4961,9 +5003,17 @@ int sqlite3NotPureFunc(sqlite3_context *pCtx){
   if( pCtx->pVdbe==0 ) return 1;
 #endif
   if( pCtx->pVdbe->aOp[pCtx->iOp].opcode==OP_PureFunc ){
+#if 0
+    char *zMsg = sqlite3_mprintf(
+       "non-deterministic use of %s() in an index, CHECK constraint, "
+       "or generated column", pCtx->pFunc->zName);
+    sqlite3_result_error(pCtx, zMsg, -1);
+    sqlite3_free(zMsg);
+#else
     sqlite3_result_error(pCtx, 
        "non-deterministic function in index expression or CHECK constraint",
        -1);
+#endif
     return 0;
   }
   return 1;