Added benchmark of parsing.

BUILD

@@ -231,6 +231,17 @@ cc_binary(
 
 # C/C++ tests ##################################################################
 
+cc_binary(
+    name = "benchmark",
+    testonly = 1,
+    srcs = ["tests/benchmark.cc"],
+    deps = [
+        ":descriptor_upbproto",
+        ":descriptor_upbreflection",
+        "@com_github_google_benchmark//:benchmark_main",
+    ],
+)
+
 cc_library(
     name = "upb_test",
     testonly = 1,

WORKSPACE

@@ -23,3 +23,17 @@ http_archive(
     strip_prefix = "ragel-6.10",
     urls = ["http://www.colm.net/files/ragel/ragel-6.10.tar.gz"],
 )
+
+http_archive(
+     name = "com_google_googletest",
+     urls = ["https://github.com/google/googletest/archive/b6cd405286ed8635ece71c72f118e659f4ade3fb.zip"],  # 2019-01-07
+     strip_prefix = "googletest-b6cd405286ed8635ece71c72f118e659f4ade3fb",
+     sha256 = "ff7a82736e158c077e76188232eac77913a15dac0b22508c390ab3f88e6d6d86",
+)
+
+http_archive(
+    name = "com_github_google_benchmark",
+    urls = ["https://github.com/google/benchmark/archive/16703ff83c1ae6d53e5155df3bb3ab0bc96083be.zip"],
+    strip_prefix = "benchmark-16703ff83c1ae6d53e5155df3bb3ab0bc96083be",
+    sha256 = "59f918c8ccd4d74b6ac43484467b500f1d64b40cc1010daa055375b322a43ba3",
+)

tests/benchmark.cc

@@ -0,0 +1,36 @@
+
+#include <string.h>
+#include <benchmark/benchmark.h>
+#include "google/protobuf/descriptor.upb.h"
+#include "google/protobuf/descriptor.upbdefs.h"
+
+upb_strview descriptor = google_protobuf_descriptor_proto_upbdefinit.descriptor;
+
+/* A buffer big enough to parse descriptor.proto without going to heap. */
+char buf[65535];
+
+static void BM_CreateArena(benchmark::State& state) {
+  for (auto _ : state) {
+    upb_arena* arena = upb_arena_init(buf, sizeof(buf), NULL);
+    upb_arena_free(arena);
+  }
+}
+BENCHMARK(BM_CreateArena);
+
+static void BM_ParseDescriptor(benchmark::State& state) {
+  size_t bytes = 0;
+  for (auto _ : state) {
+    upb_arena* arena = upb_arena_init(buf, sizeof(buf), NULL);
+    google_protobuf_FileDescriptorProto* set =
+        google_protobuf_FileDescriptorProto_parse(descriptor.data,
+                                                descriptor.size, arena);
+    if (!set) {
+      printf("Failed to parse.\n");
+      exit(1);
+    }
+    bytes += descriptor.size;
+    upb_arena_free(arena);
+  }
+  state.SetBytesProcessed(state.iterations() * descriptor.size);
+}
+BENCHMARK(BM_ParseDescriptor);