Make sure the sqlite3VdbeGetOp() subroutine works even when SQLite is

compiled with SQLITE_OMIT_TRACE. (CVS 6784)

FossilOrigin-Name: 1c8ec2a6e4efbb3fdc58f999b7b725fa5dc4d0e9

manifest

@@ -1,5 +1,5 @@
-C Changes\sto\sthe\sbackup\sfunctionality\sso\sthat\sit\sworks\sbetter\swith\scodecs.\s(CVS\s6783)
-D 2009-06-18T20:52:47
+C Make\ssure\sthe\ssqlite3VdbeGetOp()\ssubroutine\sworks\seven\swhen\sSQLite\sis\ncompiled\swith\sSQLITE_OMIT_TRACE.\s(CVS\s6784)
+D 2009-06-19T00:33:32
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 8b8fb7823264331210cddf103831816c286ba446
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -146,7 +146,7 @@ F src/os_common.h 8c61457df58f1a4bd5f5adc3e90e01b37bf7afbc
 F src/os_os2.c bed77dc26e3a95ce4a204936b9a1ca6fe612fcc5
 F src/os_unix.c b64129c296e480c2827606e206ea51bb30904626
 F src/os_win.c 725c38a524d168ce280446ad8761d731bc516405
-F src/pager.c 4c21c7ac6777cca4efa1855070b099d2f964ec64
+F src/pager.c 3edf86ef797defae17bc32407626ca2ce7442d7b
 F src/pager.h 5aec418bf99f568b92ae82816a1463400513726d
 F src/parse.y bab89225c2543a350ef96995926520bbbd781aba
 F src/pcache.c 395f752a13574120bd7513a400ba02a265aaa76d
@@ -207,7 +207,7 @@ F src/vdbe.c 09925c462891da6d2efdd68e657f3e072620177e
 F src/vdbe.h 35a648bc3279a120da24f34d9a25213ec15daf8a
 F src/vdbeInt.h 3727128255a93d116e454f67d4559700f7ae4d6f
 F src/vdbeapi.c 619992b16821b989050e8a12e259d795d30731a9
-F src/vdbeaux.c 14e1c6065172530a14648292371ccd3c1ea0d490
+F src/vdbeaux.c 77b6734303c58e36db65f6e63795425546905059
 F src/vdbeblob.c c25d7e7bc6d5917feeb17270bd275fa771f26e5c
 F src/vdbemem.c ba39c0afa609595c7c23dfc2ac929d9414faa59f
 F src/vtab.c 98fbffc5efe68d8107511dec0a650efc7daa9446
@@ -736,7 +736,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl 672f81d693a03f80f5ae60bfefacd8a349e76746
-P ed08b53cd64c4ff2c94ef4e48441c5236041c9ca
-R 398bd4d99486dbc4ce2de243d75a2f75
+P 87d6796d986e4d5238252e704d936ab4407a0265
+R a70a1ca61dc3d6f4216d562f52d535d5
 U drh
-Z c91ffb1e85d44ff0c9e62c342254c34c
+Z 9502f7414b8e904937dc49dc8f715629

manifest.uuid

@@ -1 +1 @@
-87d6796d986e4d5238252e704d936ab4407a0265
+1c8ec2a6e4efbb3fdc58f999b7b725fa5dc4d0e9

src/pager.c

@@ -18,7 +18,7 @@
 ** file simultaneously, or one process from reading the database while
 ** another is writing.
 **
-** @(#) $Id: pager.c,v 1.595 2009/06/18 20:52:47 drh Exp $
+** @(#) $Id: pager.c,v 1.596 2009/06/19 00:33:32 drh Exp $
 */
 #ifndef SQLITE_OMIT_DISKIO
 #include "sqliteInt.h"

src/vdbeaux.c

@@ -14,7 +14,7 @@
 ** to version 2.8.7, all this code was combined into the vdbe.c source file.
 ** But that file was getting too big so this subroutines were split out.
 **
-** $Id: vdbeaux.c,v 1.460 2009/06/09 18:58:53 shane Exp $
+** $Id: vdbeaux.c,v 1.461 2009/06/19 00:33:32 drh Exp $
 */
 #include "sqliteInt.h"
 #include "vdbeInt.h"
@@ -626,11 +626,24 @@ void sqlite3VdbeNoopComment(Vdbe *p, const char *zFormat, ...){
 ** is readable and writable, but it has no effect.  The return of a dummy
 ** opcode allows the call to continue functioning after a OOM fault without
 ** having to check to see if the return from this routine is a valid pointer.
+**
+** About the #ifdef SQLITE_OMIT_TRACE:  Normally, this routine is never called
+** unless p->nOp>0.  This is because in the absense of SQLITE_OMIT_TRACE,
+** an OP_Trace instruction is always inserted by sqlite3VdbeGet() as soon as
+** a new VDBE is created.  So we are free to set addr to p->nOp-1 without
+** having to double-check to make sure that the result is non-negative. But
+** if SQLITE_OMIT_TRACE is defined, the OP_Trace is omitted and we do need to
+** check the value of p->nOp-1 before continuing.
 */
 VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
   static VdbeOp dummy;
   assert( p->magic==VDBE_MAGIC_INIT );
-  if( addr<0 ) addr = p->nOp - 1;
+  if( addr<0 ){
+#ifdef SQLITE_OMIT_TRACE
+    if( p->nOp==0 ) return &dummy;
+#endif
+    addr = p->nOp - 1;
+  }
   assert( (addr>=0 && addr<p->nOp) || p->db->mallocFailed );
   if( p->db->mallocFailed ){
     return &dummy;