[Localization] Implement .def to .strings converter tool

tools/CMakeLists.txt

@@ -23,6 +23,7 @@ add_swift_tool_subdirectory(swift-dependency-tool)
 add_swift_tool_subdirectory(swift-demangle)
 add_swift_tool_subdirectory(swift-demangle-yamldump)
 add_swift_tool_subdirectory(swift-def-to-yaml-converter)
+add_swift_tool_subdirectory(swift-def-to-strings-converter)
 add_swift_tool_subdirectory(swift-serialize-diagnostics)
 add_swift_tool_subdirectory(sil-func-extractor)
 add_swift_tool_subdirectory(sil-llvm-gen)

tools/swift-def-to-strings-converter/CMakeLists.txt

@@ -0,0 +1,7 @@
+add_swift_host_tool(swift-def-to-strings-converter
+  swift-def-to-strings-converter.cpp
+  SWIFT_COMPONENT tools
+)
+
+target_link_libraries(swift-def-to-strings-converter PRIVATE
+  swiftLocalization)

tools/swift-def-to-strings-converter/swift-def-to-strings-converter.cpp

@@ -0,0 +1,104 @@
+//===--- swift-def-to-strings-converter.cpp -------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// Create a .strings file from the diagnostic messages text in `.def` files.
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/Basic/LLVMInitialize.h"
+#include "swift/Basic/Compiler.h"
+#include "swift/Localization/LocalizationFormat.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/EndianStream.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cstdlib>
+#include <string>
+#include <system_error>
+
+static constexpr const char *const diagnosticID[] = {
+#define DIAG(KIND, ID, Options, Text, Signature) #ID,
+#include "swift/AST/DiagnosticsAll.def"
+};
+
+static constexpr const char *const diagnosticMessages[] = {
+#define DIAG(KIND, ID, Options, Text, Signature) Text,
+#include "swift/AST/DiagnosticsAll.def"
+};
+
+enum LocalDiagID : uint32_t {
+#define DIAG(KIND, ID, Options, Text, Signature) ID,
+#include "swift/AST/DiagnosticsAll.def"
+  NumDiags
+};
+
+namespace options {
+
+static llvm::cl::OptionCategory
+    Category("swift-def-to-strings-converter Options");
+
+static llvm::cl::opt<std::string>
+    OutputDirectory("output-directory",
+                    llvm::cl::desc("Directory for the output file"),
+                    llvm::cl::cat(Category));
+
+static llvm::cl::opt<std::string>
+    OutputFilename("output-filename",
+                   llvm::cl::desc("Filename for the output file"),
+                   llvm::cl::cat(Category));
+
+} // namespace options
+
+int main(int argc, char *argv[]) {
+  PROGRAM_START(argc, argv);
+
+  llvm::cl::HideUnrelatedOptions(options::Category);
+  llvm::cl::ParseCommandLineOptions(argc, argv,
+                                    "Swift `.def` to `.strings` Converter\n");
+
+  llvm::SmallString<128> LocalizedFilePath;
+  if (options::OutputFilename.empty()) {
+    // The default language for localization is English
+    std::string defaultLocaleCode = "en";
+    LocalizedFilePath = options::OutputDirectory;
+    llvm::sys::path::append(LocalizedFilePath, defaultLocaleCode);
+    llvm::sys::path::replace_extension(LocalizedFilePath, ".strings");
+  } else {
+    LocalizedFilePath = options::OutputFilename;
+  }
+
+  std::error_code error;
+  llvm::raw_fd_ostream OS(LocalizedFilePath.str(), error,
+                          llvm::sys::fs::OF_None);
+
+  if (OS.has_error() || error) {
+    llvm::errs() << "Error has occurred while trying to write to "
+                 << LocalizedFilePath.str()
+                 << " with error code: " << error.message() << "\n";
+    return EXIT_FAILURE;
+  }
+
+  llvm::ArrayRef<const char *> ids(diagnosticID, LocalDiagID::NumDiags);
+  llvm::ArrayRef<const char *> messages(diagnosticMessages,
+                                        LocalDiagID::NumDiags);
+
+  swift::diag::DefToStringsConverter converter(ids, messages);
+  converter.convert(OS);
+
+  return EXIT_SUCCESS;
+}