Merge pull request #245 from Tokutek/gcc-4.9-support

Support gcc 4.9 in cmake, fix uninitialized value warnings

CMakeLists.txt

@@ -7,6 +7,31 @@ project(TokuDB)
 set(CMAKE_SHARED_LIBRARY_LINK_C_FLAGS "")
 set(CMAKE_SHARED_LIBRARY_LINK_CXX_FLAGS "")
 
+## Versions of gcc >= 4.9.0 require special version of 'ar' and 'ranlib' for
+## link-time optimizations to work properly.
+##
+## From https://gcc.gnu.org/gcc-4.9/changes.html:
+##
+##     When using a linker plugin, compiling with the -flto option now
+##     generates slim objects files (.o) which only contain intermediate
+##     language representation for LTO. Use -ffat-lto-objects to create
+##     files which contain additionally the object code. To generate
+##     static libraries suitable for LTO processing, use gcc-ar and
+##     gcc-ranlib; to list symbols from a slim object file use
+##     gcc-nm. (Requires that ar, ranlib and nm have been compiled with
+##     plugin support.)
+if ((CMAKE_CXX_COMPILER_ID STREQUAL GNU) AND
+    NOT (CMAKE_CXX_COMPILER_VERSION VERSION_LESS "4.9.0"))
+  find_program(gcc_ar "gcc-ar")
+  if (gcc_ar)
+    set(CMAKE_AR "${gcc_ar}")
+  endif ()
+  find_program(gcc_ranlib "gcc-ranlib")
+  if (gcc_ranlib)
+    set(CMAKE_RANLIB "${gcc_ranlib}")
+  endif ()
+endif()
+
 include(TokuFeatureDetection)
 include(TokuSetupCompiler)
 include(TokuSetupCTest)

ft/log_upgrade.cc

@@ -321,8 +321,8 @@ toku_maybe_upgrade_log(const char *env_dir, const char *log_dir, LSN * lsn_of_cl
         r = 0; //Logs are up to date
     else {
         FOOTPRINT(4);
-        LSN last_lsn;
-        TXNID last_xid;
+        LSN last_lsn = ZERO_LSN;
+        TXNID last_xid = TXNID_NONE;
         r = verify_clean_shutdown_of_log_version(log_dir, version_of_logs_on_disk, &last_lsn, &last_xid);
         if (r != 0) {
             goto cleanup;

ft/logger.cc

@@ -621,7 +621,7 @@ int toku_logger_find_next_unused_log_file(const char *directory, long long *resu
     if (d==0) return get_error_errno();
     while ((de=readdir(d))) {
         if (de==0) return get_error_errno();
-        long long thisl;
+        long long thisl = -1;
         if ( is_a_logfile(de->d_name, &thisl) ) {
             if ((long long)thisl > maxf) maxf = thisl;
         }