tools/gn/function_set_default_toolchain.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/build_settings.h"
#include "tools/gn/functions.h"
#include "tools/gn/parse_tree.h"
#include "tools/gn/scope.h"
#include "tools/gn/settings.h"
#include "tools/gn/toolchain_manager.h"

/*
set_default_toolchain: Sets the default toolchain name.

  set_default_toolchain(toolchain_label)

  The given label should identify a toolchain definition (see "toolchain").
  This toolchain will be used for all targets unless otherwise specified.

  This function is only valid to call during the processing of the build
  configuration file. Since the build configuration file is processed
  separately for each toolchain, this function will be a no-op when called
  under any non-default toolchains.

  For example, the default toolchain should be appropriate for the current
  environment. If the current environment is 32-bit and somebody references
  a target with a 64-bit toolchain, we wouldn't want processing of the build
  config file for the 64-bit toolchain to reset the default toolchain to
  64-bit, we want to keep it 32-bits.

Argument:

  toolchain_label:
      Toolchain name.

Example:

  set_default_toolchain("//build/config/win:vs32")
*/

Value ExecuteSetDefaultToolchain(Scope* scope,
                                 const FunctionCallNode* function,
                                 const std::vector<Value>& args,
                                 Err* err) {
  if (!scope->IsProcessingBuildConfig()) {
    *err = Err(function->function(), "Must be called from build config.",
        "set_default_toolchain can only be called from the build configuration "
        "file.");
    return Value();
  }

  // Ignore non-default-build-config invocations.
  if (!scope->IsProcessingDefaultBuildConfig())
    return Value();

  const SourceDir& current_dir = SourceDirForFunctionCall(function);
  const Label& default_toolchain = ToolchainLabelForScope(scope);

  if (!EnsureSingleStringArg(function, args, err))
    return Value();
  Label toolchain_label(
      Label::Resolve(current_dir, default_toolchain, args[0], err));
  if (toolchain_label.is_null())
    return Value();

  ToolchainManager& mgr =
      scope->settings()->build_settings()->toolchain_manager();
  mgr.SetDefaultToolchainUnlocked(toolchain_label, function->GetRange(), err);
  return Value();
}