From: drh <drh@noemail.net>
Date: Mon, 29 May 2017 14:26:07 +0000 (+0000)
Subject: Optimizations to the Walker object and its methods to make the code a little
X-Git-Tag: version-3.20.0~240
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=979dd1be5710eb2ed38a46b1712cf5da74947c2a;p=thirdparty%2Fsqlite.git

Optimizations to the Walker object and its methods to make the code a little
smaller and to help it run a little faster.

FossilOrigin-Name: 6854a34ed708259f2280f7ee56cec09f7fc99810dc739dc2814ddeae286aa2c4
---

diff --git a/manifest b/manifest
index fcb8b8238e..36f2144283 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Correctly\sinitialize\sthe\siSelectId\sof\sFROM\sclause\sterms\sthat\sare\sa\sself\njoin\sof\sa\sreused\smaterialized\ssubquery.\s\sWithout\sthis,\sthe\sEXPLAIN\sQUERY\sPLAN\noutput\sfor\sthe\squery\swill\sidentify\sthe\ssubquery\susing\sthe\suninitialized\n(and\sarbitrary)\siSelectId.
-D 2017-05-29T13:09:24.519
+C Optimizations\sto\sthe\sWalker\sobject\sand\sits\smethods\sto\smake\sthe\scode\sa\slittle\nsmaller\sand\sto\shelp\sit\srun\sa\slittle\sfaster.
+D 2017-05-29T14:26:07.045
 F Makefile.in 1cc758ce3374a32425e4d130c2fe7b026b20de5b8843243de75f087c0a2661fb
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 8eeb80162074004e906b53d7340a12a14c471a83743aab975947e95ce061efcc
@@ -357,7 +357,7 @@ F src/ctime.c 47d91a25ad8f199a71a5b1b7b169d6dd0d6e98c5719eca801568798743d1161c
 F src/date.c cc42a41c7422389860d40419a5e3bce5eaf6e7835c3ba2677751dc653550a5c7
 F src/dbstat.c 19ee7a4e89979d4df8e44cfac7a8f905ec89b77d
 F src/delete.c bc2bfc227002ebe091e7cc321f09a48e52f86e1cd5ff9b028009db0671556749
-F src/expr.c 30f61b7d8236def0e99485651e5d983a102afa4cbc8b1ef0ab19ccb1f3841f99
+F src/expr.c 82ccc704a2e5aa114f2a2c67610b87963add6d65336f352bb1782a2942356bcb
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c db65492ae549c3b548c9ef1f279ce1684f1c473b116e1c56a90878cd5dcf968d
 F src/func.c 9d52522cc8ae7f5cdadfe14594262f1618bc1f86083c4cd6da861b4cf5af6174
@@ -402,14 +402,14 @@ F src/pragma.h 37a1311d0388db480388d7ec09054f7103045eff20d4971f8a433b77f40b9921
 F src/prepare.c b1140c3d0cf59bc85ace00ce363153041b424b7a
 F src/printf.c 8757834f1b54dae512fb25eb1acc8e94a0d15dd2290b58f2563f65973265adb2
 F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
-F src/resolve.c 3e518b962d932a997fae373366880fc028c75706
+F src/resolve.c ffb69e203f18a7c4013c0b37e657e19abd61379c92480dbbd582bd365c5876aa
 F src/rowset.c 7b7e7e479212e65b723bf40128c7b36dc5afdfac
-F src/select.c ecdb34eb3393633ca98f5e1a4228d83da3fb838a37db7bb5a3e2f838b2e52658
+F src/select.c fd0a17fb78130fe840a33024888d41c77ed0bab0340b72cf71b1558d5f465e88
 F src/shell.c 3f761fe604174b31aacd2ea2eacef5e6fe550111d60c0d71532cc008c68cf3f3
 F src/sqlite.h.in 8dd468837a4f6d76713e3a4cc65bea48095009038593d41040ab46c1b351197f
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 58fd0676d3111d02e62e5a35992a7d3da5d3f88753acc174f2d37b774fbbdd28
-F src/sqliteInt.h aea3aa1b81e0d07d5b1c39b8c5a54a1dc5e4f10136cb63da392aef9eb2a5108b
+F src/sqliteInt.h 80c485ad08b1091a6148637c1b9c334be6ab39cb0d28b839bab96e6783b9d006
 F src/sqliteLimit.h 1513bfb7b20378aa0041e7022d04acb73525de35b80b252f1b83fedb4de6a76b
 F src/status.c a9e66593dfb28a9e746cba7153f84d49c1ddc4b1
 F src/table.c b46ad567748f24a326d9de40e5b9659f96ffff34
@@ -484,7 +484,7 @@ F src/vtab.c 35b9bdc2b41de32a417141d12097bcc4e29a77ed7cdb8f836d1d2305d946b61b
 F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c 40c543f0a2195d1b0dc88ef12142bea690009344
 F src/wal.h 06b2a0b599cc0f53ea97f497cf8c6b758c999f71
-F src/walker.c b71a992b413b3a022572eccf29ef4b4890223791
+F src/walker.c d46044e7a5842560dfe7122d93ff5145dd4a96f4d0bf5ba5910a7731b8c01e79
 F src/where.c 67f98714b07ec3c1d5e033a63d23c0fd70c24861b7b46b69b10700f22dca6ffe
 F src/whereInt.h 2a4b634d63ce488b46d4b0da8f2eaa8f9aeab202bc25ef76f007de5e3fba1f20
 F src/wherecode.c 8ad48867660519e262a401720845dc76934f86f558ec9606335fafcd7a2554f8
@@ -1581,7 +1581,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 7cc940a97efc096ff3725710f526c06f52453bd923fb9e825ce6990275df747a
-R 35dcf48f31a7a8cf76b469de7e6b34dc
+P 43c9ae371f6250fee98a7c4011726eff8ad37f5a97add4f490ac3a2dd501a0d2
+R 453c4ffd0fd2d3ef84551e2d5c6aff9e
 U drh
-Z 3804513f19d04eacb2ef4a093a6026f8
+Z 17a17047de4968bc6d150d2777390a09
diff --git a/manifest.uuid b/manifest.uuid
index c803b5e6fc..61857b1385 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-43c9ae371f6250fee98a7c4011726eff8ad37f5a97add4f490ac3a2dd501a0d2
\ No newline at end of file
+6854a34ed708259f2280f7ee56cec09f7fc99810dc739dc2814ddeae286aa2c4
\ No newline at end of file
diff --git a/src/expr.c b/src/expr.c
index 201dedcc8a..707dfe4563 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -1772,10 +1772,12 @@ static int selectNodeIsConstant(Walker *pWalker, Select *NotUsed){
 }
 static int exprIsConst(Expr *p, int initFlag, int iCur){
   Walker w;
-  memset(&w, 0, sizeof(w));
   w.eCode = initFlag;
   w.xExprCallback = exprNodeIsConstant;
   w.xSelectCallback = selectNodeIsConstant;
+#ifdef SQLITE_DEBUG
+  w.xSelectCallback2 = sqlite3SelectWalkAssert2;
+#endif
   w.u.iCur = iCur;
   sqlite3WalkExpr(&w, p);
   return w.eCode;
@@ -1863,9 +1865,9 @@ static int exprNodeIsConstantOrGroupBy(Walker *pWalker, Expr *pExpr){
 */
 int sqlite3ExprIsConstantOrGroupBy(Parse *pParse, Expr *p, ExprList *pGroupBy){
   Walker w;
-  memset(&w, 0, sizeof(w));
   w.eCode = 1;
   w.xExprCallback = exprNodeIsConstantOrGroupBy;
+  w.xSelectCallback = 0;
   w.u.pGroupBy = pGroupBy;
   w.pParse = pParse;
   sqlite3WalkExpr(&w, p);
@@ -1893,10 +1895,12 @@ int sqlite3ExprIsConstantOrFunction(Expr *p, u8 isInit){
 */
 int sqlite3ExprContainsSubquery(Expr *p){
   Walker w;
-  memset(&w, 0, sizeof(w));
   w.eCode = 1;
   w.xExprCallback = sqlite3ExprWalkNoop;
   w.xSelectCallback = selectNodeIsConstant;
+#ifdef SQLITE_DEBUG
+  w.xSelectCallback2 = sqlite3SelectWalkAssert2;
+#endif
   sqlite3WalkExpr(&w, p);
   return w.eCode==0;
 }
@@ -4901,8 +4905,8 @@ int sqlite3FunctionUsesThisSrc(Expr *pExpr, SrcList *pSrcList){
   Walker w;
   struct SrcCount cnt;
   assert( pExpr->op==TK_AGG_FUNCTION );
-  memset(&w, 0, sizeof(w));
   w.xExprCallback = exprSrcCount;
+  w.xSelectCallback = 0;
   w.u.pSrcCount = &cnt;
   cnt.pSrc = pSrcList;
   cnt.nThis = 0;
@@ -5074,10 +5078,14 @@ static int analyzeAggregate(Walker *pWalker, Expr *pExpr){
   return WRC_Continue;
 }
 static int analyzeAggregatesInSelect(Walker *pWalker, Select *pSelect){
-  UNUSED_PARAMETER(pWalker);
   UNUSED_PARAMETER(pSelect);
+  pWalker->walkerDepth++;
   return WRC_Continue;
 }
+static void analyzeAggregatesInSelectEnd(Walker *pWalker, Select *pSelect){
+  UNUSED_PARAMETER(pSelect);
+  pWalker->walkerDepth--;
+}
 
 /*
 ** Analyze the pExpr expression looking for aggregate functions and
@@ -5090,9 +5098,10 @@ static int analyzeAggregatesInSelect(Walker *pWalker, Select *pSelect){
 */
 void sqlite3ExprAnalyzeAggregates(NameContext *pNC, Expr *pExpr){
   Walker w;
-  memset(&w, 0, sizeof(w));
   w.xExprCallback = analyzeAggregate;
   w.xSelectCallback = analyzeAggregatesInSelect;
+  w.xSelectCallback2 = analyzeAggregatesInSelectEnd;
+  w.walkerDepth = 0;
   w.u.pNC = pNC;
   assert( pNC->pSrcList!=0 );
   sqlite3WalkExpr(&w, pExpr);
diff --git a/src/resolve.c b/src/resolve.c
index 6b3caa625a..aed48260ec 100644
--- a/src/resolve.c
+++ b/src/resolve.c
@@ -1446,8 +1446,6 @@ int sqlite3ResolveExprNames(
   w.xExprCallback = resolveExprStep;
   w.xSelectCallback = resolveSelectStep;
   w.xSelectCallback2 = 0;
-  w.walkerDepth = 0;
-  w.eCode = 0;
   w.u.pNC = pNC;
   sqlite3WalkExpr(&w, pExpr);
 #if SQLITE_MAX_EXPR_DEPTH>0
@@ -1501,9 +1499,9 @@ void sqlite3ResolveSelectNames(
   Walker w;
 
   assert( p!=0 );
-  memset(&w, 0, sizeof(w));
   w.xExprCallback = resolveExprStep;
   w.xSelectCallback = resolveSelectStep;
+  w.xSelectCallback2 = 0;
   w.pParse = pParse;
   w.u.pNC = pOuterNC;
   sqlite3WalkSelect(&w, p);
diff --git a/src/select.c b/src/select.c
index a8547f8112..9d4c159198 100644
--- a/src/select.c
+++ b/src/select.c
@@ -4610,6 +4610,25 @@ int sqlite3ExprWalkNoop(Walker *NotUsed, Expr *NotUsed2){
   return WRC_Continue;
 }
 
+/*
+** No-op routine for the parse-tree walker for SELECT statements.
+** subquery in the parser tree.
+*/
+int sqlite3SelectWalkNoop(Walker *NotUsed, Select *NotUsed2){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  return WRC_Continue;
+}
+
+#if SQLITE_DEBUG
+/*
+** Always assert.  This xSelectCallback2 implementation proves that the
+** xSelectCallback2 is never invoked.
+*/
+void sqlite3SelectWalkAssert2(Walker *NotUsed, Select *NotUsed2){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  assert( 0 );
+}
+#endif
 /*
 ** This routine "expands" a SELECT statement and all of its subqueries.
 ** For additional information on what it means to "expand" a SELECT
@@ -4625,11 +4644,11 @@ int sqlite3ExprWalkNoop(Walker *NotUsed, Expr *NotUsed2){
 */
 static void sqlite3SelectExpand(Parse *pParse, Select *pSelect){
   Walker w;
-  memset(&w, 0, sizeof(w));
   w.xExprCallback = sqlite3ExprWalkNoop;
   w.pParse = pParse;
   if( pParse->hasCompound ){
     w.xSelectCallback = convertCompoundSelectToSubquery;
+    w.xSelectCallback2 = 0;
     sqlite3WalkSelect(&w, pSelect);
   }
   w.xSelectCallback = selectExpander;
@@ -4689,7 +4708,7 @@ static void selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
 static void sqlite3SelectAddTypeInfo(Parse *pParse, Select *pSelect){
 #ifndef SQLITE_OMIT_SUBQUERY
   Walker w;
-  memset(&w, 0, sizeof(w));
+  w.xSelectCallback = sqlite3SelectWalkNoop;
   w.xSelectCallback2 = selectAddSubqueryTypeInfo;
   w.xExprCallback = sqlite3ExprWalkNoop;
   w.pParse = pParse;
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index fc24885e28..7c78fdb426 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3337,6 +3337,10 @@ int sqlite3WalkSelect(Walker*, Select*);
 int sqlite3WalkSelectExpr(Walker*, Select*);
 int sqlite3WalkSelectFrom(Walker*, Select*);
 int sqlite3ExprWalkNoop(Walker*, Expr*);
+int sqlite3SelectWalkNoop(Walker*, Select*);
+#ifdef SQLITE_DEBUG
+void sqlite3SelectWalkAssert2(Walker*, Select*);
+#endif
 
 /*
 ** Return code from the parse-tree walking primitives and their
diff --git a/src/walker.c b/src/walker.c
index a7123d8ab0..dc874a259d 100644
--- a/src/walker.c
+++ b/src/walker.c
@@ -124,8 +124,9 @@ int sqlite3WalkSelectFrom(Walker *pWalker, Select *p){
 **
 ** If it is not NULL, the xSelectCallback() callback is invoked before
 ** the walk of the expressions and FROM clause. The xSelectCallback2()
-** method, if it is not NULL, is invoked following the walk of the 
-** expressions and FROM clause.
+** method is invoked following the walk of the expressions and FROM clause,
+** but only if both xSelectCallback and xSelectCallback2 are both non-NULL
+** and if the expressions and FROM clause both return WRC_Continue;
 **
 ** Return WRC_Continue under normal conditions.  Return WRC_Abort if
 ** there is an abort request.
@@ -135,27 +136,19 @@ int sqlite3WalkSelectFrom(Walker *pWalker, Select *p){
 */
 int sqlite3WalkSelect(Walker *pWalker, Select *p){
   int rc;
-  if( p==0 || (pWalker->xSelectCallback==0 && pWalker->xSelectCallback2==0) ){
-    return WRC_Continue;
-  }
-  rc = WRC_Continue;
-  pWalker->walkerDepth++;
-  while( p ){
-    if( pWalker->xSelectCallback ){
-       rc = pWalker->xSelectCallback(pWalker, p);
-       if( rc ) break;
-    }
+  if( p==0 || pWalker->xSelectCallback==0 ) return WRC_Continue;
+  do{
+    rc = pWalker->xSelectCallback(pWalker, p);
+    if( rc ) return rc & WRC_Abort;
     if( sqlite3WalkSelectExpr(pWalker, p)
      || sqlite3WalkSelectFrom(pWalker, p)
     ){
-      pWalker->walkerDepth--;
       return WRC_Abort;
     }
     if( pWalker->xSelectCallback2 ){
       pWalker->xSelectCallback2(pWalker, p);
     }
     p = p->pPrior;
-  }
-  pWalker->walkerDepth--;
-  return rc & WRC_Abort;
+  }while( p!=0 );
+  return WRC_Continue;
 }