Merged: [wasm] compile fuzzer: initialize temporary before filling.

test/fuzzer/wasm-compile.cc

 // Copyright 2017 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stddef.h>
 #include <stdint.h>
 #include <stdlib.h>
 
 #include <algorithm>
 
@@ skipping 39 matching lines @@
       index = 0;
     }
     return split(index);
   }
 
   template <typename T>
   T get() {
     if (size() == 0) {
       return T();
     } else {
+      // We want to support the case where we have less than sizeof(T) bytes
+      // remaining in the slice. For example, if we emit an i32 constant, it's
+      // okay if we don't have a full four bytes available, we'll just use what
+      // we have. We aren't concerned about endianness because we are generating
+      // arbitrary expressions.
       const size_t num_bytes = std::min(sizeof(T), size());
-      T result;
+      T result = T();
       memcpy(&result, data_, num_bytes);
       data_ += num_bytes;
       size_ -= num_bytes;
       return result;
     }
   }
 };
 
 class WasmGenerator {
   template <WasmOpcode Op, ValueType... Args>
@@ skipping 361 matching lines @@
     if (!possible_nondeterminism && (result_interpreted != result_compiled)) {
       printf("\nInterpreter returned 0x%x but compiled code returned 0x%x\n",
              result_interpreted, result_compiled);
       V8_Fatal(__FILE__, __LINE__, "WasmCodeFuzzerHash=%x",
                v8::internal::StringHasher::HashSequentialString(
                    data, static_cast<int>(size), WASM_CODE_FUZZER_HASH_SEED));
     }
   }
   return 0;
 }