Extend --apple_bitcode to take an optional platform and allow multi…

…ple occurrences.

This change changes `--apple_bitcode` in a backward-compatible way to accept `--apple_bitcode=[platform=]mode`, where `platform` is `ios`, `macos`, `tvos`, or `watchos`. If a platform is specified, the given Bitcode mode will be applied specifically to that platform; if omitted, the option behaves as before, applying the Bitcode mode to all platforms. The option can be listed multiple times, with later ones winning, so a default can be set for all platforms and then overridden for specific ones.

This new format can be useful, for example, when building watchOS apps that must be distributed with Bitcode but where you do not want to build the companion iOS app with it enabled. To achieve this, pass `--apple_bitcode=watchos=embedded` to your build invocation.

RELNOTES: `--apple_bitcode` now takes an optional platform and only applies the Bitcode mode to that platform if present. The option may be provided multiple times.
PiperOrigin-RevId: 324023106

src/main/java/com/google/devtools/build/lib/rules/apple/AppleBitcodeConverter.java

@@ -0,0 +1,103 @@
+// Copyright 2020 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.apple;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.collect.Maps;
+import com.google.devtools.build.lib.rules.apple.AppleCommandLineOptions.AppleBitcodeMode;
+import com.google.devtools.common.options.Converter;
+import com.google.devtools.common.options.OptionsParsingException;
+import java.util.Map;
+
+/**
+ * Converts the {@code --apple_bitcode} command line option to a pair containing an optional
+ * platform type and the bitcode mode to apply to builds targeting that platform.
+ */
+public final class AppleBitcodeConverter
+    implements Converter<Map.Entry<ApplePlatform.PlatformType, AppleBitcodeMode>> {
+  /** Used to convert Bitcode mode strings to their enum value. */
+  private static final AppleBitcodeMode.Converter MODE_CONVERTER = new AppleBitcodeMode.Converter();
+
+  /** Used to convert Apple platform type strings to their enum value. */
+  private static final AppleCommandLineOptions.PlatformTypeConverter PLATFORM_TYPE_CONVERTER =
+      new AppleCommandLineOptions.PlatformTypeConverter();
+
+  private static final String TYPE_DESCRIPTION =
+      String.format(
+          "'mode' or 'platform=mode', where 'mode' is %s, and 'platform' is %s",
+          MODE_CONVERTER.getTypeDescription(), PLATFORM_TYPE_CONVERTER.getTypeDescription());
+
+  @VisibleForTesting
+  public static final String INVALID_APPLE_BITCODE_OPTION_FORMAT =
+      "Apple Bitcode mode must be in the form " + TYPE_DESCRIPTION;
+
+  @Override
+  public Map.Entry<ApplePlatform.PlatformType, AppleBitcodeMode> convert(String input)
+      throws OptionsParsingException {
+    ApplePlatform.PlatformType platformType;
+    AppleBitcodeMode mode;
+
+    int pos = input.indexOf('=');
+    if (pos < 0) {
+      // If there was no '=', then parse it as a Bitcode mode and apply it to all platforms (by
+      // using a null key in the entry).
+      platformType = null;
+      mode = convertAppleBitcodeMode(input);
+    } else {
+      // If there was a '=', then parse the platform type from the left side, the Bitcode mode from
+      // the right side, and apply it to just that platform.
+      String platformTypeName = input.substring(0, pos);
+      String modeName = input.substring(pos + 1);
+
+      platformType = convertPlatformType(platformTypeName);
+      mode = convertAppleBitcodeMode(modeName);
+    }
+
+    return Maps.immutableEntry(platformType, mode);
+  }
+
+  @Override
+  public String getTypeDescription() {
+    return TYPE_DESCRIPTION;
+  }
+
+  /**
+   * Returns the {@code AppleBitcodeMode} value that is equivalent to the given string.
+   *
+   * @throws OptionsParsingException if the string was not a valid Apple Bitcode mode
+   */
+  private static AppleBitcodeMode convertAppleBitcodeMode(String input)
+      throws OptionsParsingException {
+    try {
+      return MODE_CONVERTER.convert(input);
+    } catch (OptionsParsingException e) {
+      throw new OptionsParsingException(INVALID_APPLE_BITCODE_OPTION_FORMAT, e);
+    }
+  }
+
+  /**
+   * Returns the {@code ApplePlatform.PlatformType} value that is equivalent to the given string.
+   *
+   * @throws OptionsParsingException if any of the strings was not a valid Apple platform type
+   */
+  private static ApplePlatform.PlatformType convertPlatformType(String input)
+      throws OptionsParsingException {
+    try {
+      return PLATFORM_TYPE_CONVERTER.convert(input);
+    } catch (OptionsParsingException e) {
+      throw new OptionsParsingException(INVALID_APPLE_BITCODE_OPTION_FORMAT, e);
+    }
+  }
+}

src/main/java/com/google/devtools/build/lib/rules/apple/AppleCommandLineOptions.java

@@ -38,6 +38,7 @@
 import com.google.protobuf.CodedOutputStream;
 import java.io.IOException;
 import java.util.List;
+import java.util.Map;
 
 /** Command-line options for building for Apple platforms. */
 public class AppleCommandLineOptions extends FragmentOptions {
@@ -355,18 +356,21 @@ public DefaultProvisioningProfileConverter() {
   }
 
   @Option(
-    name = "apple_bitcode",
-    converter = AppleBitcodeMode.Converter.class,
-    // TODO(blaze-team): Default to embedded_markers when fully implemented.
-    defaultValue = "none",
-    documentationCategory = OptionDocumentationCategory.OUTPUT_PARAMETERS,
-    effectTags = {OptionEffectTag.LOSES_INCREMENTAL_STATE},
-    help =
-        "Specify the Apple bitcode mode for compile steps. "
-            + "Values: 'none', 'embedded_markers', 'embedded'."
-  )
-  public AppleBitcodeMode appleBitcodeMode;
-
+      name = "apple_bitcode",
+      allowMultiple = true,
+      converter = AppleBitcodeConverter.class,
+      defaultValue = "null",
+      documentationCategory = OptionDocumentationCategory.OUTPUT_PARAMETERS,
+      effectTags = {OptionEffectTag.LOSES_INCREMENTAL_STATE},
+      help =
+          "Specify the Apple bitcode mode for compile steps targeting device architectures. Values"
+              + " are of the form '[platform=]mode', where the platform (which must be 'ios',"
+              + " 'macos', 'tvos', or 'watchos') is optional. If provided, the bitcode mode is"
+              + " applied for that platform specifically; if omitted, it is applied for all"
+              + " platforms. The mode must be 'none', 'embedded_markers', or 'embedded'. This"
+              + " option may be provided multiple times.")
+  public List<Map.Entry<ApplePlatform.PlatformType, AppleBitcodeMode>> appleBitcodeMode;
+
   /** Returns whether the minimum OS version is explicitly set for the current platform. */
   public DottedVersion getMinimumOsVersion() {
     DottedVersion.Option option;

src/main/java/com/google/devtools/build/lib/rules/apple/AppleConfiguration.java

@@ -33,7 +33,10 @@
 import com.google.devtools.build.lib.rules.apple.ApplePlatform.PlatformType;
 import com.google.devtools.build.lib.skylarkbuildapi.apple.AppleConfigurationApi;
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.EnumMap;
 import java.util.List;
+import java.util.Map;
 import javax.annotation.Nullable;
 
 /** A configuration containing flags required for Apple platforms and tools. */
@@ -70,7 +73,7 @@ public class AppleConfiguration extends Fragment implements AppleConfigurationAp
   private final ImmutableList<String> watchosCpus;
   private final ImmutableList<String> tvosCpus;
   private final ImmutableList<String> macosCpus;
-  private final AppleBitcodeMode bitcodeMode;
+  private final EnumMap<ApplePlatform.PlatformType, AppleBitcodeMode> platformBitcodeModes;
   private final Label xcodeConfigLabel;
   private final AppleCommandLineOptions options;
   @Nullable private final Label defaultProvisioningProfileLabel;
@@ -95,7 +98,7 @@ private AppleConfiguration(AppleCommandLineOptions options, String iosCpu) {
     this.macosCpus = (options.macosCpus == null || options.macosCpus.isEmpty())
         ? ImmutableList.of(AppleCommandLineOptions.DEFAULT_MACOS_CPU)
         : ImmutableList.copyOf(options.macosCpus);
-    this.bitcodeMode = options.appleBitcodeMode;
+    this.platformBitcodeModes = collectBitcodeModes(options.appleBitcodeMode);
     this.xcodeConfigLabel =
         Preconditions.checkNotNull(options.xcodeVersionConfig, "xcodeConfigLabel");
     this.defaultProvisioningProfileLabel = options.defaultProvisioningProfile;
@@ -357,11 +360,13 @@ public ImmutableList<String> getIosMultiCpus() {
    */
   @Override
   public AppleBitcodeMode getBitcodeMode() {
-    if (hasValidSingleArchPlatform() && getSingleArchPlatform().isDevice()) {
-      return bitcodeMode;
-    } else {
-      return AppleBitcodeMode.NONE;
+    if (hasValidSingleArchPlatform()) {
+      ApplePlatform platform = getSingleArchPlatform();
+      if (platform.isDevice()) {
+        return platformBitcodeModes.get(applePlatformType);
+      }
     }
+    return AppleBitcodeMode.NONE;
   }
 
   /**
@@ -433,6 +438,35 @@ static AppleConfiguration create(AppleCommandLineOptions appleOptions, String cp
     return new AppleConfiguration(appleOptions, iosCpuFromCpu(cpu));
   }
 
+  /**
+   * Compute the platform-type-to-bitcode-mode mapping from the pairs that were passed on the
+   * command line.
+   */
+  private static EnumMap<ApplePlatform.PlatformType, AppleBitcodeMode> collectBitcodeModes(
+      List<Map.Entry<ApplePlatform.PlatformType, AppleBitcodeMode>> platformModeMappings) {
+    EnumMap<ApplePlatform.PlatformType, AppleBitcodeMode> modes =
+        new EnumMap<>(ApplePlatform.PlatformType.class);
+    ApplePlatform.PlatformType[] allPlatforms = ApplePlatform.PlatformType.values();
+
+    // Seed the map with the default mode for every key so that there is a valid mode for every
+    // platform.
+    // TODO(blaze-team): Default to embedded_markers when fully implemented.
+    Arrays.stream(allPlatforms).forEach(platform -> modes.put(platform, AppleBitcodeMode.NONE));
+
+    // Process the entries in order. If we encounter one with a null key, apply the mode to all
+    // platforms; otherwise, apply it only to that specific platform. This ensures that the later
+    // options override the earlier options.
+    for (Map.Entry<ApplePlatform.PlatformType, AppleBitcodeMode> entry : platformModeMappings) {
+      if (entry.getKey() == null) {
+        Arrays.stream(allPlatforms).forEach(platform -> modes.put(platform, entry.getValue()));
+      } else {
+        modes.put(entry.getKey(), entry.getValue());
+      }
+    }
+
+    return modes;
+  }
+
   /**
    * Loads {@link AppleConfiguration} from build options.
    */

src/test/java/com/google/devtools/build/lib/rules/objc/ObjcLibraryTest.java

@@ -17,6 +17,7 @@
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.google.devtools.build.lib.actions.util.ActionsTestUtil.baseArtifactNames;
+import static com.google.devtools.build.lib.rules.apple.AppleBitcodeConverter.INVALID_APPLE_BITCODE_OPTION_FORMAT;
 import static com.google.devtools.build.lib.rules.objc.CompilationSupport.ABSOLUTE_INCLUDES_PATH_FORMAT;
 import static com.google.devtools.build.lib.rules.objc.CompilationSupport.BOTH_MODULE_NAME_AND_MODULE_MAP_SPECIFIED;
 import static com.google.devtools.build.lib.rules.objc.CompilationSupport.FILE_IN_SRCS_AND_HDRS_WARNING_FORMAT;
@@ -677,6 +678,138 @@ public void testCompilationActionsWithBitcode_simulator() throws Exception {
     assertThat(compileActionA.getArguments()).doesNotContain("-fembed-bitcode-marker");
   }
 
+  @Test
+  public void testCompilationActionsWithEmbeddedBitcodeForMultiplePlatformsWithMatch()
+      throws Exception {
+    useConfiguration(
+        "--apple_platform_type=ios",
+        "--ios_multi_cpus=arm64",
+        "--apple_bitcode=ios=embedded",
+        "--apple_bitcode=watchos=embedded");
+    createLibraryTargetWriter("//objc:lib")
+        .setAndCreateFiles("srcs", "a.m", "b.m", "private.h")
+        .setAndCreateFiles("hdrs", "c.h")
+        .write();
+
+    CommandAction compileActionA = compileAction("//objc:lib", "a.o");
+
+    assertThat(compileActionA.getArguments()).contains("-fembed-bitcode");
+  }
+
+  @Test
+  public void testCompilationActionsWithEmbeddedBitcodeForMultiplePlatformsWithoutMatch()
+      throws Exception {
+    useConfiguration(
+        "--apple_platform_type=ios",
+        "--ios_multi_cpus=arm64",
+        "--apple_bitcode=tvos=embedded",
+        "--apple_bitcode=watchos=embedded");
+    createLibraryTargetWriter("//objc:lib")
+        .setAndCreateFiles("srcs", "a.m", "b.m", "private.h")
+        .setAndCreateFiles("hdrs", "c.h")
+        .write();
+
+    CommandAction compileActionA = compileAction("//objc:lib", "a.o");
+
+    assertThat(compileActionA.getArguments()).doesNotContain("-fembed-bitcode");
+    assertThat(compileActionA.getArguments()).doesNotContain("-fembed-bitcode-marker");
+  }
+
+  @Test
+  public void testLaterBitcodeOptionsOverrideEarlierOptionsForSamePlatform() throws Exception {
+    useConfiguration(
+        "--apple_platform_type=ios",
+        "--ios_multi_cpus=arm64",
+        "--apple_bitcode=ios=embedded",
+        "--apple_bitcode=ios=embedded_markers");
+    createLibraryTargetWriter("//objc:lib")
+        .setAndCreateFiles("srcs", "a.m", "b.m", "private.h")
+        .setAndCreateFiles("hdrs", "c.h")
+        .write();
+
+    CommandAction compileActionA = compileAction("//objc:lib", "a.o");
+
+    assertThat(compileActionA.getArguments()).doesNotContain("-fembed-bitcode");
+    assertThat(compileActionA.getArguments()).contains("-fembed-bitcode-marker");
+  }
+
+  @Test
+  public void testLaterPlatformBitcodeOptionWithPlatformOverridesEarlierOptionWithoutPlatform()
+      throws Exception {
+    useConfiguration(
+        "--apple_platform_type=ios",
+        "--ios_multi_cpus=arm64",
+        "--apple_bitcode=ios=embedded",
+        "--apple_bitcode=embedded_markers");
+    createLibraryTargetWriter("//objc:lib")
+        .setAndCreateFiles("srcs", "a.m", "b.m", "private.h")
+        .setAndCreateFiles("hdrs", "c.h")
+        .write();
+
+    CommandAction compileActionA = compileAction("//objc:lib", "a.o");
+
+    assertThat(compileActionA.getArguments()).doesNotContain("-fembed-bitcode");
+    assertThat(compileActionA.getArguments()).contains("-fembed-bitcode-marker");
+  }
+
+  @Test
+  public void testLaterBitcodeOptionWithoutPlatformOverridesEarlierOptionWithPlatform()
+      throws Exception {
+    useConfiguration(
+        "--apple_platform_type=ios",
+        "--ios_multi_cpus=arm64",
+        "--apple_bitcode=embedded",
+        "--apple_bitcode=ios=embedded_markers");
+    createLibraryTargetWriter("//objc:lib")
+        .setAndCreateFiles("srcs", "a.m", "b.m", "private.h")
+        .setAndCreateFiles("hdrs", "c.h")
+        .write();
+
+    CommandAction compileActionA = compileAction("//objc:lib", "a.o");
+
+    assertThat(compileActionA.getArguments()).doesNotContain("-fembed-bitcode");
+    assertThat(compileActionA.getArguments()).contains("-fembed-bitcode-marker");
+  }
+
+  @Test
+  public void testAppleBitcode_invalidPlatformNameGivesError() throws Exception {
+    checkBitcodeModeError(
+        "--apple_platform_type=ios",
+        "--ios_multi_cpus=arm64",
+        "--apple_bitcode=ios=embedded",
+        "--apple_bitcode=nachos=embedded");
+  }
+
+  @Test
+  public void testAppleBitcode_invalidBitcodeModeGivesError() throws Exception {
+    checkBitcodeModeError(
+        "--apple_platform_type=ios", "--ios_multi_cpus=arm64", "--apple_bitcode=indebted");
+  }
+
+  @Test
+  public void testAppleBitcode_invalidBitcodeModeWithPlatformGivesError() throws Exception {
+    checkBitcodeModeError(
+        "--apple_platform_type=ios", "--ios_multi_cpus=arm64", "--apple_bitcode=ios=indebted");
+  }
+
+  @Test
+  public void testAppleBitcode_emptyBitcodeModeGivesError() throws Exception {
+    checkBitcodeModeError(
+        "--apple_platform_type=ios", "--ios_multi_cpus=arm64", "--apple_bitcode=ios=");
+  }
+
+  @Test
+  public void testAppleBitcode_emptyValueGivesError() throws Exception {
+    checkBitcodeModeError(
+        "--apple_platform_type=ios", "--ios_multi_cpus=arm64", "--apple_bitcode=");
+  }
+
+  private void checkBitcodeModeError(String... args) throws Exception {
+    OptionsParsingException thrown =
+        assertThrows(OptionsParsingException.class, () -> useConfiguration(args));
+    assertThat(thrown).hasMessageThat().contains(INVALID_APPLE_BITCODE_OPTION_FORMAT);
+  }
+
   @Test
   public void testModuleNameAttributeChangesName() throws Exception {
     RULE_TYPE.scratchTarget(scratch, "module_name", "'foo'");