Enhance the IdList object to exist in a single memory allocation (rather than

a separate allocate for the base object and the array of IDs).  Also permit
an IdList object to store an Expr pointer together with each name.

FossilOrigin-Name: 40f3c95871e6f40f287ef2756abafb8fc56dffdd0af69436e5c7d8e95022d94e

5 files changed, 54 insertions, 30 deletions

diff --git a/src/build.c b/src/build.c
index 22f7a79e0..30908500a 100644
--- a/src/build.c
+++ b/src/build.c
@@ -4672,18 +4672,17 @@ IdList *sqlite3IdListAppend(Parse *pParse, IdList *pList, Token *pToken){
   if( pList==0 ){
     pList = sqlite3DbMallocZero(db, sizeof(IdList) );
     if( pList==0 ) return 0;
+  }else{
+    IdList *pNew;
+    pNew = sqlite3DbRealloc(db, pList,
+                 sizeof(IdList) + pList->nId*sizeof(pList->a));
+    if( pNew==0 ){
+      sqlite3IdListDelete(db, pList);
+      return 0;
+    }
+    pList = pNew;
   }
-  pList->a = sqlite3ArrayAllocate(
-      db,
-      pList->a,
-      sizeof(pList->a[0]),
-      &pList->nId,
-      &i
-  );
-  if( i<0 ){
-    sqlite3IdListDelete(db, pList);
-    return 0;
-  }
+  i = pList->nId++;
   pList->a[i].zName = sqlite3NameFromToken(db, pToken);
   if( IN_RENAME_OBJECT && pList->a[i].zName ){
     sqlite3RenameTokenMap(pParse, (void*)pList->a[i].zName, pToken);
@@ -4696,11 +4695,13 @@ IdList *sqlite3IdListAppend(Parse *pParse, IdList *pList, Token *pToken){
 */
 void sqlite3IdListDelete(sqlite3 *db, IdList *pList){
   int i;
+  int delExpr;
   if( pList==0 ) return;
+  delExpr = pList->eU4==EU4_EXPR;
   for(i=0; i<pList->nId; i++){
     sqlite3DbFree(db, pList->a[i].zName);
+    if( delExpr ) sqlite3ExprDelete(db, pList->a[i].u4.pExpr);
   }
-  sqlite3DbFree(db, pList->a);
   sqlite3DbFreeNN(db, pList);
 }
 
diff --git a/src/expr.c b/src/expr.c
index e6d7f9e69..4e036c934 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -1698,22 +1698,16 @@ IdList *sqlite3IdListDup(sqlite3 *db, const IdList *p){
   int i;
   assert( db!=0 );
   if( p==0 ) return 0;
-  pNew = sqlite3DbMallocRawNN(db, sizeof(*pNew) );
+  assert( p->eU4!=EU4_EXPR );
+  pNew = sqlite3DbMallocRawNN(db, sizeof(*pNew)+(p->nId-1)*sizeof(p->a[0]) );
   if( pNew==0 ) return 0;
   pNew->nId = p->nId;
-  pNew->a = sqlite3DbMallocRawNN(db, p->nId*sizeof(p->a[0]) );
-  if( pNew->a==0 ){
-    sqlite3DbFreeNN(db, pNew);
-    return 0;
-  }
-  /* Note that because the size of the allocation for p->a[] is not
-  ** necessarily a power of two, sqlite3IdListAppend() may not be called
-  ** on the duplicate created by this function. */
+  pNew->eU4 = p->eU4;
   for(i=0; i<p->nId; i++){
     struct IdList_item *pNewItem = &pNew->a[i];
-    struct IdList_item *pOldItem = &p->a[i];
+    const struct IdList_item *pOldItem = &p->a[i];
     pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
-    pNewItem->idx = pOldItem->idx;
+    pNewItem->u4 = pOldItem->u4;
   }
   return pNew;
 }
diff --git a/src/insert.c b/src/insert.c
index 2593f353b..9b97b99a3 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -851,13 +851,15 @@ void sqlite3Insert(
   */
   bIdListInOrder = (pTab->tabFlags & (TF_OOOHidden|TF_HasStored))==0;
   if( pColumn ){
+    assert( pColumn->eU4!=EU4_EXPR );
+    pColumn->eU4 = EU4_IDX;
     for(i=0; i<pColumn->nId; i++){
-      pColumn->a[i].idx = -1;
+      pColumn->a[i].u4.idx = -1;
     }
     for(i=0; i<pColumn->nId; i++){
       for(j=0; j<pTab->nCol; j++){
         if( sqlite3StrICmp(pColumn->a[i].zName, pTab->aCol[j].zCnName)==0 ){
-          pColumn->a[i].idx = j;
+          pColumn->a[i].u4.idx = j;
           if( i!=j ) bIdListInOrder = 0;
           if( j==pTab->iPKey ){
             ipkColumn = i;  assert( !withoutRowid );
@@ -1159,7 +1161,8 @@ void sqlite3Insert(
       }
     }
     if( pColumn ){
-      for(j=0; j<pColumn->nId && pColumn->a[j].idx!=i; j++){}
+      assert( pColumn->eU4==EU4_IDX );
+      for(j=0; j<pColumn->nId && pColumn->a[j].u4.idx!=i; j++){}
       if( j>=pColumn->nId ){
         /* A column not named in the insert column list gets its
         ** default value */
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 1cd3e75b4..3a9d8b8a0 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3038,14 +3038,26 @@ struct ExprList {
 ** If "a" is the k-th column of table "t", then IdList.a[0].idx==k.
 */
 struct IdList {
+  int nId;         /* Number of identifiers on the list */
+  u8 eU4;          /* Which element of a.u4 is valid */
   struct IdList_item {
     char *zName;      /* Name of the identifier */
-    int idx;          /* Index in some Table.aCol[] of a column named zName */
-  } *a;
-  int nId;         /* Number of identifiers on the list */
+    union {
+      int idx;          /* Index in some Table.aCol[] of a column named zName */
+      Expr *pExpr;      /* Expr to implement a USING variable */
+    } u4;
+  } a[1];
 };
 
 /*
+** Allowed values for IdList.eType, which determines which value of the a.u4
+** is valid.
+*/
+#define EU4_NONE   0   /* Does not use IdList.a.u4 */
+#define EU4_IDX    1   /* Uses IdList.a.u4.idx */
+#define EU4_EXPR   2   /* Uses IdList.a.u4.pExpr */
+
+/*
 ** The SrcItem object represents a single term in the FROM clause of a query.
 ** The SrcList object is mostly an array of SrcItems.
 **
diff --git a/src/treeview.c b/src/treeview.c
index 0a3f94267..ff5558aca 100644
--- a/src/treeview.c
+++ b/src/treeview.c
@@ -846,7 +846,21 @@ void sqlite3TreeViewBareIdList(
       if( zName==0 ) zName = "(null)";
       sqlite3TreeViewPush(&pView, moreToFollow);
       sqlite3TreeViewLine(pView, 0);
-      fprintf(stdout, "%s (%d)\n", zName, pList->a[i].idx);
+      if( pList->eU4==EU4_NONE ){
+        fprintf(stdout, "%s\n", zName);
+      }else if( pList->eU4==EU4_IDX ){
+        fprintf(stdout, "%s (%d)\n", zName, pList->a[i].u4.idx);
+      }else{
+        assert( pList->eU4==EU4_EXPR );
+        if( pList->a[i].u4.pExpr==0 ){
+          fprintf(stdout, "%s (pExpr=NULL)\n", zName);
+        }else{
+          fprintf(stdout, "%s\n", zName);
+          sqlite3TreeViewPush(&pView, i<pList->nId-1);
+          sqlite3TreeViewExpr(pView, pList->a[i].u4.pExpr, 0);
+          sqlite3TreeViewPop(&pView);
+        }
+      }
       sqlite3TreeViewPop(&pView);
     }
   }