1 files changed, 82 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/AppleCrosstoolTransition.java b/src/main/java/com/google/devtools/build/lib/rules/objc/AppleCrosstoolTransition.java
new file mode 100644
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--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/AppleCrosstoolTransition.java
@@ -0,0 +1,82 @@
+// Copyright 2016 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.rules.objc;
+
+import com.google.common.collect.ImmutableList;
+import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
+import com.google.devtools.build.lib.analysis.config.BuildOptions;
+import com.google.devtools.build.lib.packages.Attribute.SplitTransition;
+import com.google.devtools.build.lib.rules.apple.AppleCommandLineOptions;
+import com.google.devtools.build.lib.rules.apple.AppleConfiguration.ConfigurationDistinguisher;
+import com.google.devtools.build.lib.rules.cpp.CppOptions;
+import java.util.List;
+
+/**
+ * Transition that produces a configuration that causes c++ toolchain selection to use the
+ * CROSSTOOL given in apple_crosstool_top.
+ */
+public class AppleCrosstoolTransition implements SplitTransition<BuildOptions> {
+
+  /**
+   * A singleton instance of AppleCrosstoolTransition.
+   */
+  public static final SplitTransition<BuildOptions> APPLE_CROSSTOOL_TRANSITION =
+      new AppleCrosstoolTransition();
+  
+  @Override
+  public boolean defaultsToSelf() {
+    return true;
+  }
+
+  @Override
+  public List<BuildOptions> split(BuildOptions buildOptions) {
+    BuildOptions result = buildOptions.clone();
+    result.get(AppleCommandLineOptions.class).configurationDistinguisher =
+        ConfigurationDistinguisher.APPLE_CROSSTOOL;
+
+
+    // TODO(b/29355778): Once ios_cpu is retired, introduce another top-level flag (perhaps
+    // --apple_cpu) for toolchain selection in top-level consuming rules.
+    String cpu = "ios_" + buildOptions.get(AppleCommandLineOptions.class).iosCpu;
+    setAppleCrosstoolTransitionConfiguration(buildOptions, result, cpu);
+    return ImmutableList.of(result);
+  }
+  
+  /**
+   * Sets configuration fields required for a transition that uses apple_crosstool_top in place of
+   * the default CROSSTOOL.
+   *
+   * @param from options from the originating configuration
+   * @param to options for the destination configuration. This instance will be modified
+   *     to so the destination configuration uses the apple crosstool
+   * @param cpu {@code --cpu} value for toolchain selection in the destination configuration
+   */
+  public static void setAppleCrosstoolTransitionConfiguration(BuildOptions from,
+      BuildOptions to, String cpu) {
+    to.get(BuildConfiguration.Options.class).cpu = cpu;
+    to.get(CppOptions.class).crosstoolTop =
+        from.get(AppleCommandLineOptions.class).appleCrosstoolTop; 
+
+    // --compiler = "compiler" for all OSX toolchains.  We do not support asan/tsan, cfi, etc. on
+    // darwin.
+    to.get(CppOptions.class).cppCompiler = "compiler";
+
+    // OSX toolchains always use the runtime of the platform they are targeting (i.e. we do not
+    // support custom production environments).
+    to.get(CppOptions.class).libcTop = null;
+    to.get(CppOptions.class).glibc = null; 
+  }
+  
+}