Fix two potential (and apparently harmless) shift overflows discovered by

the -fcatch-undefined-behavior option of clang.

FossilOrigin-Name: e19eead8c9977ed4f00eac54c5bc7e90db78caa8

manifest

@@ -1,5 +1,5 @@
-C Remove\sa\sbranch\sin\sSTAT4\slogic\sthat\sis\sno\slonger\sreachable\safter\s\nthe\sprevious\schange.
-D 2013-12-03T19:49:55.482
+C Fix\stwo\spotential\s(and\sapparently\sharmless)\sshift\soverflows\sdiscovered\sby\nthe\s-fcatch-undefined-behavior\soption\sof\sclang.
+D 2013-12-05T16:41:55.583
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in e1a9b4258bbde53f5636f4e238c65b7e11459e2b
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -205,7 +205,7 @@ F src/notify.c 976dd0f6171d4588e89e874fcc765e92914b6d30
 F src/os.c b4ad71336fd96f97776f75587cd9e8218288f5be
 F src/os.h 4a46270a64e9193af4a0aaa3bc2c66dc07c29b3f
 F src/os_common.h 92815ed65f805560b66166e3583470ff94478f04
-F src/os_unix.c 143624d9eabb3b997c59cf594e0d06c56edd43e9
+F src/os_unix.c f076587029285554a3a65d30d0e71d50cd61f41f
 F src/os_win.c 4323dd0bac4f7a7037fc4cf87fb4692d17f0b108
 F src/pager.c 2aa4444ffe86e9282d03bc349a4a5e49bd77c0e8
 F src/pager.h f094af9f6ececfaa8a1e93876905a4f34233fb0c
@@ -278,7 +278,7 @@ F src/tokenize.c ec4c1a62b890bf1dbcdb966399e140b904c700a4
 F src/trigger.c d84e1f3669e9a217731a14a9d472b1c7b87c87ba
 F src/update.c d1c2477dcf14d90999d1935af4efb4806553250b
 F src/utf.c 6fc6c88d50448c469c5c196acf21617a24f90269
-F src/util.c c1d47254d805074226eb68bab2327f2559799d88
+F src/util.c 76ed0519296e3f62e97e57dab1999e34184c8e49
 F src/vacuum.c 3728d74919d4fb1356f9e9a13e27773db60b7179
 F src/vdbe.c 54894fde8dc806d259e015ac7c9680145e725835
 F src/vdbe.h c06f0813f853566457ce9cfb1a4a4bc39a5da644
@@ -1145,7 +1145,7 @@ F tool/vdbe-compress.tcl f12c884766bd14277f4fcedcae07078011717381
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh d1a6de74685f360ab718efda6265994b99bbea01
 F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff
-P 33ad4f91477907b7b3e5808c7ba11aacc9a83ba6
-R b9a8385eb7153992ed9d3229f4d58e8a
+P eca7d3f1612c7a009a9e4ef89f76f9b7e275d1e6
+R ba7aebdef816e4dde9f2f30108dfb7a9
 U drh
-Z 1abf6c68d7a5a613f293f6a4e7a65cb6
+Z d225deef3eea562cd29618981c6f7c47

manifest.uuid

@@ -1 +1 @@
-eca7d3f1612c7a009a9e4ef89f76f9b7e275d1e6
+e19eead8c9977ed4f00eac54c5bc7e90db78caa8

src/os_unix.c

@@ -4081,7 +4081,7 @@ static int unixShmSystemLock(
 #ifdef SQLITE_DEBUG
   { u16 mask;
   OSTRACE(("SHM-LOCK "));
-  mask = (1<<(ofst+n)) - (1<<ofst);
+  mask = ofst>31 ? 0xffffffff : (1<<(ofst+n)) - (1<<ofst);
   if( rc==SQLITE_OK ){
     if( lockType==F_UNLCK ){
       OSTRACE(("unlock %d ok", ofst));

src/util.c

@@ -1281,6 +1281,8 @@ u64 sqlite3LogEstToInt(LogEst x){
   x /= 10;
   if( n>=5 ) n -= 2;
   else if( n>=1 ) n -= 1;
-  if( x>=3 ) return (n+8)<<(x-3);
+  if( x>=3 ){
+    return x>60 ? (u64)LARGEST_INT64 : (n+8)<<(x-3);
+  }
   return (n+8)>>(3-x);
 }