Simplifications to the expression code generator. Remove about 80 lines of

older and obsolete code.

FossilOrigin-Name: 53f5cfe11516d0496c7760378b6305c3088d479f

manifest

@@ -1,8 +1,8 @@
 -----BEGIN PGP SIGNED MESSAGE-----
 Hash: SHA1
 
-C Enhance\sthe\sANALYZE\scommand\sso\sthat\sit\sgathers\sstatistics\sin\sthe\ssqlite_stat1\ntable\seven\sfor\stables\sthat\sare\sempty\sor\shave\sno\sindices.
+C Simplifications\sto\sthe\sexpression\scode\sgenerator.\s\sRemove\sabout\s80\slines\sof\nolder\sand\sobsolete\scode.
-D 2010-09-25T22:32:56
+D 2010-09-27T18:14:12
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in c599a15d268b1db2aeadea19df2adc3bf2eb6bee
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -130,7 +130,7 @@ F src/complete.c dc1d136c0feee03c2f7550bafc0d29075e36deac
 F src/ctime.c 4f3aadad62c6c9f0d4e5a96718516ac4e3c598df
 F src/date.c 5dd8448a0bfea8d31fb14cff487d0c06ff8c8b20
 F src/delete.c 7ed8a8c8b5f748ece92df173d7e0f7810c899ebd
-F src/expr.c 21ad2494bd7c0826072216ea0f20db86a0a4ac82
+F src/expr.c d2ffe8ed8eed8208c3e550cfba98a2a301a64108
 F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
 F src/fkey.c 58bbf52c6ddd3f64ca40a3230f9e548a83a5cb16
 F src/func.c caa6c5134106d95cced4db80ce3fdcdde4f6c8d4
@@ -180,7 +180,7 @@ F src/select.c b0b124781474e4e0c8f64022875e5e2009e13443
 F src/shell.c 8517fc1f9c59ae4007e6cc8b9af91ab231ea2056
 F src/sqlite.h.in dae3f74d7b2b516967ede39b8e503718b571d9da
 F src/sqlite3ext.h 69dfb8116af51b84a029cddb3b35062354270c89
-F src/sqliteInt.h d8ae67308fec3f2abdce817a630aceae42ad8043
+F src/sqliteInt.h 224c8e31f88489ea015c695bcf1877f3701b404c
 F src/sqliteLimit.h a17dcd3fb775d63b64a43a55c54cb282f9726f44
 F src/status.c 496913d4e8441195f6f2a75b1c95993a45b9b30b
 F src/table.c 2cd62736f845d82200acfa1287e33feb3c15d62e
@@ -870,14 +870,14 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P 20e16fef55c355a1d7e97d0c390769b941e83fdb
+P a7645d293801da64a7579737d0a8b48117af2e2c
-R 96b44d864f75b35f18ba4c7ab3226d4c
+R 31b9d8f725b1355a3ecd589f9c768e32
 U drh
-Z e1547e0aba5840882b569e70505d3edd
+Z da56ebaf0e041408b3401a85ccd2b2a6
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+iD8DBQFMoN73oxKgR168RlERAqBjAJ4/xTLrVYlxWxhlWBOiHhf+ogrH4gCdGQFv
-P4TBzZ9lm4AFS3sK2f1UkgA=
+0abukVW0mExAm/y5XFe9a7M=
-=phK5
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manifest.uuid

@@ -1 +1 @@
-a7645d293801da64a7579737d0a8b48117af2e2c
+53f5cfe11516d0496c7760378b6305c3088d479f

src/expr.c

@@ -2234,73 +2234,6 @@ static int usedAsColumnCache(Parse *pParse, int iFrom, int iTo){
 }
 #endif /* SQLITE_DEBUG || SQLITE_COVERAGE_TEST */
 
-/*
-** If the last instruction coded is an ephemeral copy of any of
-** the registers in the nReg registers beginning with iReg, then
-** convert the last instruction from OP_SCopy to OP_Copy.
-*/
-void sqlite3ExprHardCopy(Parse *pParse, int iReg, int nReg){
-  VdbeOp *pOp;
-  Vdbe *v;
-
-  assert( pParse->db->mallocFailed==0 );
-  v = pParse->pVdbe;
-  assert( v!=0 );
-  pOp = sqlite3VdbeGetOp(v, -1);
-  assert( pOp!=0 );
-  if( pOp->opcode==OP_SCopy && pOp->p1>=iReg && pOp->p1<iReg+nReg ){
-    pOp->opcode = OP_Copy;
-  }
-}
-
-/*
-** Generate code to store the value of the iAlias-th alias in register
-** target.  The first time this is called, pExpr is evaluated to compute
-** the value of the alias.  The value is stored in an auxiliary register
-** and the number of that register is returned.  On subsequent calls,
-** the register number is returned without generating any code.
-**
-** Note that in order for this to work, code must be generated in the
-** same order that it is executed.
-**
-** Aliases are numbered starting with 1.  So iAlias is in the range
-** of 1 to pParse->nAlias inclusive.  
-**
-** pParse->aAlias[iAlias-1] records the register number where the value
-** of the iAlias-th alias is stored.  If zero, that means that the
-** alias has not yet been computed.
-*/
-static int codeAlias(Parse *pParse, int iAlias, Expr *pExpr, int target){
-#if 0
-  sqlite3 *db = pParse->db;
-  int iReg;
-  if( pParse->nAliasAlloc<pParse->nAlias ){
-    pParse->aAlias = sqlite3DbReallocOrFree(db, pParse->aAlias,
-                                 sizeof(pParse->aAlias[0])*pParse->nAlias );
-    testcase( db->mallocFailed && pParse->nAliasAlloc>0 );
-    if( db->mallocFailed ) return 0;
-    memset(&pParse->aAlias[pParse->nAliasAlloc], 0,
-           (pParse->nAlias-pParse->nAliasAlloc)*sizeof(pParse->aAlias[0]));
-    pParse->nAliasAlloc = pParse->nAlias;
-  }
-  assert( iAlias>0 && iAlias<=pParse->nAlias );
-  iReg = pParse->aAlias[iAlias-1];
-  if( iReg==0 ){
-    if( pParse->iCacheLevel>0 ){
-      iReg = sqlite3ExprCodeTarget(pParse, pExpr, target);
-    }else{
-      iReg = ++pParse->nMem;
-      sqlite3ExprCode(pParse, pExpr, iReg);
-      pParse->aAlias[iAlias-1] = iReg;
-    }
-  }
-  return iReg;
-#else
-  UNUSED_PARAMETER(iAlias);
-  return sqlite3ExprCodeTarget(pParse, pExpr, target);
-#endif
-}
-
 /*
 ** Generate code into the current Vdbe to evaluate the given
 ** expression.  Attempt to store the results in register "target".
@@ -2409,7 +2342,7 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
       break;
     }
     case TK_AS: {
-      inReg = codeAlias(pParse, pExpr->iTable, pExpr->pLeft, target);
+      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
       break;
     }
 #ifndef SQLITE_OMIT_CAST
@@ -3112,17 +3045,12 @@ int sqlite3ExprCodeExprList(
   assert( target>0 );
   n = pList->nExpr;
   for(pItem=pList->a, i=0; i<n; i++, pItem++){
-    if( pItem->iAlias ){
+    Expr *pExpr = pItem->pExpr;
-      int iReg = codeAlias(pParse, pItem->iAlias, pItem->pExpr, target+i);
+    int inReg = sqlite3ExprCodeTarget(pParse, pExpr, target+i);
-      Vdbe *v = sqlite3GetVdbe(pParse);
+    assert( pParse->pVdbe || pParse->db->mallocFailed );
-      if( iReg!=target+i ){
+    if( inReg!=target+i && pParse->pVdbe ){
-        sqlite3VdbeAddOp2(v, OP_SCopy, iReg, target+i);
+      sqlite3VdbeAddOp2(pParse->pVdbe, doHardCopy ? OP_Copy : OP_SCopy,
-      }
+                        inReg, target+i);
-    }else{
-      sqlite3ExprCode(pParse, pItem->pExpr, target+i);
-    }
-    if( doHardCopy && !pParse->db->mallocFailed ){
-      sqlite3ExprHardCopy(pParse, target, n);
     }
   }
   return n;

src/sqliteInt.h

@@ -2702,7 +2702,6 @@ void sqlite3ExprCachePop(Parse*, int);
 void sqlite3ExprCacheRemove(Parse*, int, int);
 void sqlite3ExprCacheClear(Parse*);
 void sqlite3ExprCacheAffinityChange(Parse*, int, int);
-void sqlite3ExprHardCopy(Parse*,int,int);
 int sqlite3ExprCode(Parse*, Expr*, int);
 int sqlite3ExprCodeTemp(Parse*, Expr*, int*);
 int sqlite3ExprCodeTarget(Parse*, Expr*, int);