Import chromium-63.0.3239.132

tools/gn/function_set_default_toolchain.cc

@@ -0,0 +1,86 @@
+// 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/loader.h"
+#include "tools/gn/parse_tree.h"
+#include "tools/gn/scope.h"
+#include "tools/gn/settings.h"
+
+namespace functions {
+
+const char kSetDefaultToolchain[] = "set_default_toolchain";
+const char kSetDefaultToolchain_HelpShort[] =
+    "set_default_toolchain: Sets the default toolchain name.";
+const char kSetDefaultToolchain_Help[] =
+    R"(set_default_toolchain: Sets the default toolchain name.
+
+  set_default_toolchain(toolchain_label)
+
+  The given label should identify a toolchain definition (see "gn help
+  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 only has an effect when run in the context of the
+  # default toolchain. Pick the right one according to the current CPU
+  # architecture.
+  if (target_cpu == "x64") {
+    set_default_toolchain("//toolchains:64")
+  } else if (target_cpu == "x86") {
+    set_default_toolchain("//toolchains:32")
+  }
+)";
+
+Value RunSetDefaultToolchain(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();
+  }
+
+  // When the loader is expecting the default toolchain to be set, it will set
+  // this key on the scope to point to the destination.
+  Label* default_toolchain_dest = static_cast<Label*>(
+      scope->GetProperty(Loader::kDefaultToolchainKey, nullptr));
+  if (!default_toolchain_dest)
+    return Value();
+
+  const SourceDir& current_dir = scope->GetSourceDir();
+  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();
+
+  *default_toolchain_dest = toolchain_label;
+  return Value();
+}
+
+}  // namespace functions