Suppress two CLANG Analyze warning (#4291)

Summary:
Suppress two CLANG analyze warnings. They don't seem to be real bugs
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4291

Differential Revision: D9407333

Pulled By: siying

fbshipit-source-id: 2ed63d88fa0b217fdccb1572d7508467c2203dc8

table/block_based_table_reader.cc

@@ -2840,32 +2840,32 @@ Status BlockBasedTable::DumpTable(WritableFile* out_file,
         "  ");
     out_file->Append(table_properties->ToString("\n  ", ": ").c_str());
     out_file->Append("\n");
-  }
 
-  // Output Filter blocks
-  if (!rep_->filter && !table_properties->filter_policy_name.empty()) {
-    // Support only BloomFilter as off now
-    rocksdb::BlockBasedTableOptions table_options;
-    table_options.filter_policy.reset(rocksdb::NewBloomFilterPolicy(1));
-    if (table_properties->filter_policy_name.compare(
-            table_options.filter_policy->Name()) == 0) {
-      std::string filter_block_key = kFilterBlockPrefix;
-      filter_block_key.append(table_properties->filter_policy_name);
-      BlockHandle handle;
-      if (FindMetaBlock(meta_iter.get(), filter_block_key, &handle).ok()) {
-        BlockContents block;
-        Slice dummy_comp_dict;
-        BlockFetcher block_fetcher(
-            rep_->file.get(), nullptr /* prefetch_buffer */, rep_->footer,
-            ReadOptions(), handle, &block, rep_->ioptions, false /*decompress*/,
-            dummy_comp_dict /*compression dict*/,
-            rep_->persistent_cache_options);
-        s = block_fetcher.ReadBlockContents();
-        if (!s.ok()) {
-          rep_->filter.reset(new BlockBasedFilterBlockReader(
-              prefix_extractor, table_options,
-              table_options.whole_key_filtering, std::move(block),
-              rep_->ioptions.statistics));
+    // Output Filter blocks
+    if (!rep_->filter && !table_properties->filter_policy_name.empty()) {
+      // Support only BloomFilter as off now
+      rocksdb::BlockBasedTableOptions table_options;
+      table_options.filter_policy.reset(rocksdb::NewBloomFilterPolicy(1));
+      if (table_properties->filter_policy_name.compare(
+              table_options.filter_policy->Name()) == 0) {
+        std::string filter_block_key = kFilterBlockPrefix;
+        filter_block_key.append(table_properties->filter_policy_name);
+        BlockHandle handle;
+        if (FindMetaBlock(meta_iter.get(), filter_block_key, &handle).ok()) {
+          BlockContents block;
+          Slice dummy_comp_dict;
+          BlockFetcher block_fetcher(
+              rep_->file.get(), nullptr /* prefetch_buffer */, rep_->footer,
+              ReadOptions(), handle, &block, rep_->ioptions,
+              false /*decompress*/, dummy_comp_dict /*compression dict*/,
+              rep_->persistent_cache_options);
+          s = block_fetcher.ReadBlockContents();
+          if (!s.ok()) {
+            rep_->filter.reset(new BlockBasedFilterBlockReader(
+                prefix_extractor, table_options,
+                table_options.whole_key_filtering, std::move(block),
+                rep_->ioptions.statistics));
+          }
         }
       }
     }

table/block_fetcher.cc

@@ -169,6 +169,7 @@ void BlockFetcher::GetBlockContents() {
     // page can be either uncompressed or compressed, the buffer either stack
     // or heap provided. Refer to https://github.com/facebook/rocksdb/pull/4096
     if (got_from_prefetch_buffer_ || used_buf_ == &stack_buf_[0]) {
+      assert(used_buf_ != heap_buf_.get());
       heap_buf_.reset(new char[block_size_ + kBlockTrailerSize]);
       memcpy(heap_buf_.get(), used_buf_, block_size_ + kBlockTrailerSize);
     }