Adds a JSON parser and a benchmark (json-bench) to catch performance regressions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146735 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 103 insertions, 0 deletions

diff --git a/utils/json-bench/CMakeLists.txt b/utils/json-bench/CMakeLists.txt
new file mode 100644
index 0000000000..03ac51ce64
--- /dev/null
+++ b/utils/json-bench/CMakeLists.txt
@@ -0,0 +1,5 @@
+add_llvm_utility(json-bench
+  JSONBench.cpp
+  )
+
+target_link_libraries(json-bench LLVMSupport)
diff --git a/utils/json-bench/JSONBench.cpp b/utils/json-bench/JSONBench.cpp
new file mode 100644
index 0000000000..b9f4af63d0
--- /dev/null
+++ b/utils/json-bench/JSONBench.cpp
@@ -0,0 +1,77 @@
+//===- JSONBench - Benchmark the JSONParser implementation ----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This program executes the JSONParser on differntly sized JSON texts and
+// outputs the run time.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/Twine.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/JSONParser.h"
+#include "llvm/Support/Timer.h"
+#include "llvm/Support/raw_ostream.h"
+
+static llvm::cl::opt<bool>
+Verify("verify", llvm::cl::desc(
+         "Run a quick verification useful for regression testing"),
+       llvm::cl::init(false));
+
+void benchmark(llvm::TimerGroup &Group, llvm::StringRef Name,
+               llvm::StringRef JSONText) {
+  llvm::Timer BaseLine((Name + ": Loop").str(), Group);
+  BaseLine.startTimer();
+  char C = 0;
+  for (llvm::StringRef::iterator I = JSONText.begin(),
+                                 E = JSONText.end();
+       I != E; ++I) { C += *I; }
+  BaseLine.stopTimer();
+  volatile char DontOptimizeOut = C; (void)DontOptimizeOut;
+
+  llvm::Timer Parsing((Name + ": Parsing").str(), Group);
+  Parsing.startTimer();
+  llvm::JSONParser Parser(JSONText);
+  if (!Parser.validate()) {
+    llvm::errs() << "Parsing error in JSON parser benchmark.\n";
+    exit(1);
+  }
+  Parsing.stopTimer();
+}
+
+std::string createJSONText(int N, int ValueSize) {
+  std::string JSONText;
+  llvm::raw_string_ostream Stream(JSONText);
+  Stream << "[\n";
+  for (int I = 0; I < N; ++I) {
+    Stream << " {\n"
+           << "  \"key1\": \"" << std::string(ValueSize, '*') << "\",\n"
+           << "  \"key2\": \"" << std::string(ValueSize, '*') << "\",\n"
+           << "  \"key3\": \"" << std::string(ValueSize, '*') << "\"\n"
+           << " }";
+    if (I + 1 < N) Stream << ",";
+    Stream << "\n";
+  }
+  Stream << "]\n";
+  Stream.flush();
+  return JSONText;
+}
+
+int main(int argc, char **argv) {
+  llvm::cl::ParseCommandLineOptions(argc, argv);
+  llvm::TimerGroup Group("JSON parser benchmark");
+  if (Verify) {
+    benchmark(Group, "Fast", createJSONText(1000, 500));
+  } else {
+    benchmark(Group, "Small Values", createJSONText(1000000, 5));
+    benchmark(Group, "Medium Values", createJSONText(1000000, 500));
+    benchmark(Group, "Large Values", createJSONText(10000, 50000));
+  }
+  return 0;
+}
+
diff --git a/utils/json-bench/Makefile b/utils/json-bench/Makefile
new file mode 100644
index 0000000000..6651626f68
--- /dev/null
+++ b/utils/json-bench/Makefile
@@ -0,0 +1,21 @@
+##===- utils/FileCheck/Makefile ----------------------------*- Makefile -*-===##
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../..
+TOOLNAME = json-bench
+USEDLIBS = LLVMSupport.a
+
+# This tool has no plugins, optimize startup time.
+TOOL_NO_EXPORTS = 1
+
+# Don't install this utility
+NO_INSTALL = 1
+
+include $(LEVEL)/Makefile.common
+