tools: port js2c.py to C++

This makes it easier to use third-party dependencies in this tool
(e.g. adding compression using algorithms not available in Python).
It is also much faster - locally js2c.py takes ~1.5s to generate the
output whereas this version takes ~0.1s - and consumes less memory
(~110MB v.s. 66MB).

This also modifies the js2c.py a bit to simplify the output, making
it easier to compare with one generated by the C++ version. Locally
the output from the two are identical. We'll remove js2c.py in a
subsequent commit when the C++ version is used by default.

Author: joyeecheung

Makefile

@@ -1434,6 +1434,7 @@ LINT_CPP_FILES = $(filter-out $(LINT_CPP_EXCLUDE), $(wildcard \
 	test/fixtures/*.c \
 	test/js-native-api/*/*.cc \
 	test/node-api/*/*.cc \
+	tools/js2c.cc \
 	tools/icu/*.cc \
 	tools/icu/*.h \
 	tools/code_cache/*.cc \

node.gyp

@@ -1123,6 +1123,35 @@
         }],
       ]
     }, # overlapped-checker
+    {
+      'target_name': 'node_js2c',
+      'type': 'executable',
+      'dependencies': [
+        'deps/simdutf/simdutf.gyp:simdutf',
+      ],
+      'include_dirs': [
+        'tools'
+      ],
+      'sources': [
+        'tools/js2c.cc',
+        'tools/executable_wrapper.h'
+      ],
+      'conditions': [
+        [ 'node_shared_libuv=="false"', {
+          'dependencies': [ 'deps/uv/uv.gyp:libuv' ],
+        }],
+        [ 'debug_node=="true"', {
+          'cflags!': [ '-O3' ],
+          'cflags': [ '-g', '-O0' ],
+          'defines': [ 'DEBUG' ],
+          'xcode_settings': {
+            'OTHER_CFLAGS': [
+              '-g', '-O0'
+            ],
+          },
+        }],
+      ]
+    },
     {
       'target_name': 'node_mksnapshot',
       'type': 'executable',

tools/executable_wrapper.h

@@ -0,0 +1,55 @@
+#ifndef TOOLS_EXECUTABLE_WRAPPER_H_
+#define TOOLS_EXECUTABLE_WRAPPER_H_
+
+// TODO(joyeecheung): reuse this in mksnapshot.
+#include "uv.h"
+#ifdef _WIN32
+#include <windows.h>
+#endif
+
+namespace node {
+#ifdef _WIN32
+using argv_type = wchar_t*;
+#define NODE_MAIN int wmain
+
+void FixupMain(int argc, argv_type raw_argv[], char*** argv) {
+  // Convert argv to UTF8.
+  *argv = new char*[argc + 1];
+  for (int i = 0; i < argc; i++) {
+    // Compute the size of the required buffer
+    DWORD size = WideCharToMultiByte(
+        CP_UTF8, 0, raw_argv[i], -1, nullptr, 0, nullptr, nullptr);
+    if (size == 0) {
+      // This should never happen.
+      fprintf(stderr, "Could not convert arguments to utf8.");
+      exit(1);
+    }
+    // Do the actual conversion
+    (*argv)[i] = new char[size];
+    DWORD result = WideCharToMultiByte(
+        CP_UTF8, 0, raw_argv[i], -1, (*argv)[i], size, nullptr, nullptr);
+    if (result == 0) {
+      // This should never happen.
+      fprintf(stderr, "Could not convert arguments to utf8.");
+      exit(1);
+    }
+  }
+  (*argv)[argc] = nullptr;
+}
+#else
+
+using argv_type = char*;
+#define NODE_MAIN int main
+
+void FixupMain(int argc, argv_type raw_argv[], char*** argv) {
+  *argv = uv_setup_args(argc, raw_argv);
+  // Disable stdio buffering, it interacts poorly with printf()
+  // calls elsewhere in the program (e.g., any logging from V8.)
+  setvbuf(stdout, nullptr, _IONBF, 0);
+  setvbuf(stderr, nullptr, _IONBF, 0);
+}
+#endif
+
+}  // namespace node
+
+#endif  // TOOLS_EXECUTABLE_WRAPPER_H_