Add fuzzer for spvBinaryParser (#2045)

Add fuzzer for spvBinaryParser

test/fuzzers/BUILD.gn

@@ -33,6 +33,7 @@ if (!build_with_chromium || use_fuzzing_engine) {
     testonly = true
 
     deps = [
+      ":spvtools_binary_parser_fuzzer",
       ":spvtools_opt_legalization_fuzzer",
       ":spvtools_opt_performance_fuzzer",
       ":spvtools_opt_size_fuzzer",
@@ -62,6 +63,12 @@ template("spvtools_fuzzer") {
   }
 }
 
+spvtools_fuzzer("spvtools_binary_parser_fuzzer_src") {
+  sources = [
+    "spvtools_binary_parser_fuzzer.cpp",
+  ]
+}
+
 spvtools_fuzzer("spvtools_opt_performance_fuzzer_src") {
   sources = [
     "spvtools_opt_performance_fuzzer.cpp",
@@ -87,6 +94,15 @@ spvtools_fuzzer("spvtools_val_fuzzer_src") {
 }
 
 if (!build_with_chromium || use_fuzzing_engine) {
+  fuzzer_test("spvtools_binary_parser_fuzzer") {
+    sources = []
+    deps = [
+      ":spvtools_binary_parser_fuzzer_src",
+    ]
+    # Intentionally doesn't use the seed corpus, because it consumes
+    #  part of the input as not part of the file.
+  }
+
   fuzzer_test("spvtools_opt_performance_fuzzer") {
     sources = []
     deps = [

test/fuzzers/spvtools_binary_parser_fuzzer.cpp

@@ -0,0 +1,44 @@
+// Copyright (c) 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <cstdint>
+#include <vector>
+
+#include "spirv-tools/libspirv.hpp"
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size < sizeof(spv_target_env) + 1) return 0;
+
+  const spv_context context =
+      spvContextCreate(*reinterpret_cast<const spv_target_env*>(data));
+  if (context == nullptr) return 0;
+
+  data += sizeof(spv_target_env);
+  size -= sizeof(spv_target_env);
+
+  std::vector<uint32_t> input;
+  input.resize(size >> 2);
+
+  size_t count = 0;
+  for (size_t i = 0; (i + 3) < size; i += 4) {
+    input[count++] = data[i] | (data[i + 1] << 8) | (data[i + 2] << 16) |
+                     (data[i + 3]) << 24;
+  }
+
+  spvBinaryParse(context, nullptr, input.data(), input.size(), nullptr, nullptr,
+                 nullptr);
+
+  spvContextDestroy(context);
+  return 0;
+}