Add GN function get_label_info

tools/gn/filesystem_utils.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "tools/gn/filesystem_utils.h"
 
 #include <algorithm>
 
 #include "base/file_util.h"
 #include "base/logging.h"
@@ skipping 649 matching lines @@
   }
   return SourceDir(result_str);
 }
 
 SourceDir SourceDirForCurrentDirectory(const base::FilePath& source_root) {
   base::FilePath cd;
   base::GetCurrentDirectory(&cd);
   return SourceDirForPath(source_root, cd);
 }
 
+std::string GetOutputSubdirName(const Label& toolchain_label, bool is_default) {
+  // The default toolchain has no subdir.
+  if (is_default)
+    return std::string();
+
+  // For now just assume the toolchain name is always a valid dir name. We may
+  // want to clean up the in the future.
+  return toolchain_label.name();
+}
+
 SourceDir GetToolchainOutputDir(const Settings* settings) {
   const OutputFile& toolchain_subdir = settings->toolchain_output_subdir();
 
   std::string result = settings->build_settings()->build_dir().value();
   if (!toolchain_subdir.value().empty())
     result.append(toolchain_subdir.value());
 
   return SourceDir(SourceDir::SWAP_IN, &result);
 }
 
+SourceDir GetToolchainOutputDir(const BuildSettings* build_settings,
+                                const Label& toolchain_label, bool is_default) {
+  std::string toolchain_subdir =
+      GetOutputSubdirName(toolchain_label, is_default);
+
+  std::string result = build_settings->build_dir().value();
+  if (!toolchain_subdir.empty()) {
+    result.append(toolchain_subdir);
+    result.push_back('/');
+  }
+  return SourceDir(SourceDir::SWAP_IN, &result);
+}
+
 SourceDir GetToolchainGenDir(const Settings* settings) {
   const OutputFile& toolchain_subdir = settings->toolchain_output_subdir();
 
   std::string result = settings->build_settings()->build_dir().value();
   if (!toolchain_subdir.value().empty())
     result.append(toolchain_subdir.value());
 
   result.append("gen/");
   return SourceDir(SourceDir::SWAP_IN, &result);
 }
 
+SourceDir GetToolchainGenDir(const BuildSettings* build_settings,
+                             const Label& toolchain_label, bool is_default) {
+  std::string result = GetToolchainOutputDir(
+      build_settings, toolchain_label, is_default).value();
+  result.append("gen/");
+  return SourceDir(SourceDir::SWAP_IN, &result);
+}
+
 SourceDir GetOutputDirForSourceDir(const Settings* settings,
                                    const SourceDir& source_dir) {
   SourceDir toolchain = GetToolchainOutputDir(settings);
 
   std::string ret;
   toolchain.SwapValue(&ret);
   ret.append("obj/");
 
   // The source dir should be source-absolute, so we trim off the two leading
   // slashes to append to the toolchain object directory.
@@ skipping 26 matching lines @@
   return GetGenDirForSourceDir(target->settings(), target->label().dir());
 }
 
 SourceDir GetCurrentOutputDir(const Scope* scope) {
   return GetOutputDirForSourceDir(scope->settings(), scope->GetSourceDir());
 }
 
 SourceDir GetCurrentGenDir(const Scope* scope) {
   return GetGenDirForSourceDir(scope->settings(), scope->GetSourceDir());
 }