fix or suppress errors due to -Wmaybe-uninitialized in GCC 4.8

closes #13

ft/ft-flusher.cc

@@ -783,7 +783,8 @@ move_leafentries(
     *num_bytes_moved = 0;
     for (i = lbi; i < ube; i++) {
         OMTVALUE lev;
-        toku_omt_fetch(src_bn->buffer, i, &lev);
+        int r = toku_omt_fetch(src_bn->buffer, i, &lev);
+        assert_zero(r);
         LEAFENTRY CAST_FROM_VOIDP(curr_le, lev);
         size_t le_size = leafentry_memsize(curr_le);
         *num_bytes_moved += leafentry_disksize(curr_le);
@@ -851,7 +852,7 @@ ftleaf_split(
     }
 
 
-    FTNODE B;
+    FTNODE B = nullptr;
     uint32_t fullhash;
     BLOCKNUM name;
 
@@ -875,6 +876,9 @@ ftleaf_split(
             &fullhash,
             &B
             );
+        // GCC 4.8 seems to get confused and think B is maybe uninitialized at link time.
+        // TODO(leif): figure out why it thinks this and actually fix it.
+        invariant_notnull(B);
     }
 
 
@@ -1245,7 +1249,8 @@ merge_leaf_nodes(FTNODE a, FTNODE b)
     // fill in pivot for what used to be max of node 'a', if it is needed
     if (a_has_tail) {
         OMTVALUE lev;
-        toku_omt_fetch(a_last_buffer, toku_omt_size(a_last_buffer) - 1, &lev);
+        int r = toku_omt_fetch(a_last_buffer, toku_omt_size(a_last_buffer) - 1, &lev);
+        assert_zero(r);
         LEAFENTRY CAST_FROM_VOIDP(le, lev);
         uint32_t keylen;
         void *key = le_key_and_len(le, &keylen);

ft/ft-ops.cc

@@ -4050,13 +4050,14 @@ ft_cursor_extract_key_and_val(LEAFENTRY le,
         *val = le;
         *vallen = leafentry_memsize(le);
     } else if (cursor->is_snapshot_read) {
-        le_iterate_val(
+        int r = le_iterate_val(
             le,
             does_txn_read_entry,
             val,
             vallen,
             cursor->ttxn
             );
+        lazy_assert_zero(r);
         *key = le_key_and_len(le, keylen);
     } else {
         *key = le_key_and_len(le, keylen);

ft/ft.cc

@@ -474,7 +474,7 @@ int toku_read_ft_and_store_in_cachefile (FT_HANDLE brt, CACHEFILE cf, LSN max_ac
         }
     }
     *was_open = false;
-    FT h;
+    FT h = nullptr;
     int r;
     {
         int fd = toku_cachefile_get_fd(cf);
@@ -485,6 +485,8 @@ int toku_read_ft_and_store_in_cachefile (FT_HANDLE brt, CACHEFILE cf, LSN max_ac
         }
     }
     if (r!=0) return r;
+    // GCC 4.8 seems to get confused by the gotos in the deserialize code and think h is maybe uninitialized.
+    invariant_notnull(h);
     h->cf = cf;
     h->compare_fun = brt->options.compare_fun;
     h->update_fun = brt->options.update_fun;

ft/logger.cc

@@ -1014,8 +1014,9 @@ int toku_fread_TXNID   (FILE *f, TXNID *txnid, struct x1764 *checksum, uint32_t
 int toku_fread_TXNID_PAIR   (FILE *f, TXNID_PAIR *txnid, struct x1764 *checksum, uint32_t *len) {
     TXNID parent;
     TXNID child;
-    toku_fread_TXNID(f, &parent, checksum, len);
-    toku_fread_TXNID(f, &child, checksum, len);
+    int r;
+    r = toku_fread_TXNID(f, &parent, checksum, len); if (r != 0) { return r; }
+    r = toku_fread_TXNID(f, &child, checksum, len);  if (r != 0) { return r; }
     txnid->parent_id64 = parent;
     txnid->child_id64 = child;
     return 0;

portability/tests/CMakeLists.txt

@@ -8,6 +8,15 @@ if(BUILD_TESTING)
 
   file(GLOB srcs RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" *.cc)
 
+  foreach(src ${srcs})
+    get_filename_component(test ${src} NAME_WE)
+    add_executable(${test} ${test})
+    target_link_libraries(${test} ${LIBTOKUPORTABILITY})
+    set_target_properties(${test} PROPERTIES POSITION_INDEPENDENT_CODE ON)
+    add_space_separated_property(TARGET ${test} COMPILE_FLAGS -fvisibility=hidden)
+    list(APPEND tests ${test})
+  endforeach(src)
+
   include(CheckCCompilerFlag)
   check_c_compiler_flag(-Wno-unused-result HAVE_WNO_UNUSED_RESULT)
   if (HAVE_WNO_UNUSED_RESULT)
@@ -16,17 +25,9 @@ if(BUILD_TESTING)
   check_c_compiler_flag(-Wno-maybe-uninitialized HAVE_WNO_MAYBE_UNINITIALIZED)
   if (HAVE_WNO_MAYBE_UNINITIALIZED)
     add_space_separated_property(SOURCE try-uninit COMPILE_FLAGS -Wno-maybe-uninitialized)
+    add_space_separated_property(TARGET try-uninit LINK_FLAGS -Wno-maybe-uninitialized)
   endif ()
 
-  foreach(src ${srcs})
-    get_filename_component(test ${src} NAME_WE)
-    add_executable(${test} ${test})
-    target_link_libraries(${test} ${LIBTOKUPORTABILITY})
-    set_target_properties(${test} PROPERTIES POSITION_INDEPENDENT_CODE ON)
-    add_space_separated_property(TARGET ${test} COMPILE_FLAGS -fvisibility=hidden)
-    list(APPEND tests ${test})
-  endforeach(src)
-
   configure_file(ensure_memcheck_fails.sh . COPYONLY)
   foreach(test try-leak-lost try-leak-reachable try-uninit)
     list(REMOVE_ITEM tests ${test})

src/tests/test_cursor_stickyness.cc

@@ -151,6 +151,9 @@ test_cursor_sticky (int n, int dup_mode) {
     DBC *cursor;
     r = db->cursor(db, 0, &cursor, 0); assert(r == 0);
     for (i=0; i<n; i++) {
+        // GCC 4.8 complains about these being maybe uninitialized.
+        // TODO(leif): figure out why and fix it.
+        k = 0; v = 0;
         r = cursor_get(cursor, &k, &v, DB_NEXT); assert(r == 0);
         assert(k == htonl(i)); assert(v == htonl(i));
     }

src/tests/test_txn_nested4.cc

@@ -358,8 +358,10 @@ futz_with_stack:
                 if (min_allowed_branch_level >= nest_level) {
                     //start new subtree
                     int max = nest_level + 4;
-                    if (MAX_NEST - 1 < max) max = MAX_NEST - 1;
+                    if (MAX_NEST - 1 < max) {
+                        max = MAX_NEST - 1;
                         assert(max > nest_level);
+                    }
                     int branch_level;
                     for (branch_level = nest_level + 1; branch_level <= max; branch_level++) {
                         start_txn_and_maybe_insert_or_delete(branch_level);

src/tests/test_txn_nested5.cc

@@ -377,8 +377,10 @@ futz_with_stack:
                 if (min_allowed_branch_level >= nest_level) {
                     //start new subtree
                     int max = nest_level + 4;
-                    if (MAX_NEST - 1 < max) max = MAX_NEST - 1;
+                    if (MAX_NEST - 1 < max) {
+                        max = MAX_NEST - 1;
                         assert(max > nest_level);
+                    }
                     int branch_level;
                     for (branch_level = nest_level + 1; branch_level <= max; branch_level++) {
                         start_txn_and_maybe_insert_or_delete(branch_level);