1 files changed, 69 insertions, 5 deletions

diff --git a/src/expr.c b/src/expr.c
index e4bfa995d..6050058e4 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -2346,6 +2346,52 @@ Expr *sqlite3ExprSimplifiedAndOr(Expr *pExpr){
   return pExpr;
 }
 
+/*
+** pExpr is a TK_FUNCTION node.  Try to determine whether or not the
+** function is a constant function.  A function is constant if all of
+** the following are true:
+**
+**    (1)  It is a scalar function (not an aggregate or window function)
+**    (2)  It has either the SQLITE_FUNC_CONSTANT or SQLITE_FUNC_SLOCHNG
+**         property.
+**    (3)  All of its arguments are constants
+**
+** This routine sets pWalker->eCode to 0 if pExpr is not a constant.
+** It makes no changes to pWalker->eCode if pExpr is constant.  In
+** every case, it returns WRC_Abort.
+**
+** Called as a service subroutine from exprNodeIsConstant().
+*/
+static SQLITE_NOINLINE int exprNodeIsConstantFunction(
+  Walker *pWalker,
+  Expr *pExpr
+){
+  int n;             /* Number of arguments */
+  ExprList *pList;   /* List of arguments */
+  FuncDef *pDef;     /* The function */
+  sqlite3 *db;       /* The database */
+
+  assert( pExpr->op==TK_FUNCTION );
+  if( pWalker->eCode==0 ) return WRC_Abort;
+  pList = pExpr->x.pList;
+  if( pList==0 ){
+    n = 0;
+  }else{
+    n = pList->nExpr;
+    sqlite3WalkExprList(pWalker, pList);
+    if( pWalker->eCode==0 ) return WRC_Abort;
+  }
+  db = pWalker->pParse->db;
+  pDef = sqlite3FindFunction(db, pExpr->u.zToken, n, ENC(db), 0);
+  if( pDef==0
+   || pDef->xFinalize!=0
+   || (pDef->funcFlags & (SQLITE_FUNC_CONSTANT|SQLITE_FUNC_SLOCHNG))==0
+  ){
+    pWalker->eCode = 0;
+  }
+  return WRC_Abort;
+}
+
 
 /*
 ** These routines are Walker callbacks used to check expressions to
@@ -2393,6 +2439,8 @@ static int exprNodeIsConstant(Walker *pWalker, Expr *pExpr){
       ){
         if( pWalker->eCode==5 ) ExprSetProperty(pExpr, EP_FromDDL);
         return WRC_Continue;
+      }else if( pWalker->pParse ){
+        return exprNodeIsConstantFunction(pWalker, pExpr);
       }else{
         pWalker->eCode = 0;
         return WRC_Abort;
@@ -2448,6 +2496,7 @@ static int exprNodeIsConstant(Walker *pWalker, Expr *pExpr){
 static int exprIsConst(Expr *p, int initFlag, int iCur){
   Walker w;
   w.eCode = initFlag;
+  w.pParse = 0;
   w.xExprCallback = exprNodeIsConstant;
   w.xSelectCallback = sqlite3SelectWalkFail;
 #ifdef SQLITE_DEBUG
@@ -2465,9 +2514,24 @@ static int exprIsConst(Expr *p, int initFlag, int iCur){
 ** For the purposes of this function, a double-quoted string (ex: "abc")
 ** is considered a variable but a single-quoted string (ex: 'abc') is
 ** a constant.
+**
+** The pParse parameter may be NULL.  But if it is NULL, there is no way
+** to determine if function calls are constant or not, and hence all
+** function calls will be considered to be non-constant.  If pParse is
+** not NULL, then a function call might be constant, depending on the
+** function and on its parameters.
 */
-int sqlite3ExprIsConstant(Expr *p){
-  return exprIsConst(p, 1, 0);
+int sqlite3ExprIsConstant(Parse *pParse, Expr *p){
+  Walker w;
+  w.eCode = 1;
+  w.pParse = pParse;
+  w.xExprCallback = exprNodeIsConstant;
+  w.xSelectCallback = sqlite3SelectWalkFail;
+#ifdef SQLITE_DEBUG
+  w.xSelectCallback2 = sqlite3SelectWalkAssert2;
+#endif
+  sqlite3WalkExpr(&w, p);
+  return w.eCode;
 }
 
 /*
@@ -2902,7 +2966,7 @@ static int sqlite3InRhsIsConstant(Expr *pIn){
   assert( !ExprHasProperty(pIn, EP_xIsSelect) );
   pLHS = pIn->pLeft;
   pIn->pLeft = 0;
-  res = sqlite3ExprIsConstant(pIn);
+  res = sqlite3ExprIsConstant(0, pIn);
   pIn->pLeft = pLHS;
   return res;
 }
@@ -3454,7 +3518,7 @@ void sqlite3CodeRhsOfIN(
       ** this code only executes once.  Because for a non-constant
       ** expression we need to rerun this code each time.
       */
-      if( addrOnce && !sqlite3ExprIsConstant(pE2) ){
+      if( addrOnce && !sqlite3ExprIsConstant(0, pE2) ){
         sqlite3VdbeChangeToNoop(v, addrOnce-1);
         sqlite3VdbeChangeToNoop(v, addrOnce);
         ExprClearProperty(pExpr, EP_Subrtn);
@@ -4822,7 +4886,7 @@ expr_code_doover:
       }
 
       for(i=0; i<nFarg; i++){
-        if( i<32 && sqlite3ExprIsConstant(pFarg->a[i].pExpr) ){
+        if( i<32 && sqlite3ExprIsConstant(0, pFarg->a[i].pExpr) ){
           testcase( i==31 );
           constMask |= MASKBIT32(i);
         }