Add a flag to make Apple rules not share C++ compile actions.

This is accomplished by:

- Setting the APPLE_CROSSTOOL configuration distinguisher in AppleCrosstoolTransition
- Doing nothing in AppleCrosstoolTransition in case we are already in an Apple configuration so that funky use cases like a binary having a dependency on a swift_library both directly and through an objc_library work
- Adding the "apl-" prefix to the output directory name in APPLE_CROSSTOOL configurations

Plus a few minor cleanups:

- Removed some unused methods
- Nopped out --enable_apple_crosstool_transition if the new flag is set
- Nopped out --target_uses_apple_crosstool if the new flag is set

These latter reduce the possible space of Apple configurations, thus making the code a bit more comprehensible.

RELNOTES: None.
PiperOrigin-RevId: 206157413

2 files changed, 20 insertions, 50 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/apple/AppleCommandLineOptions.java b/src/main/java/com/google/devtools/build/lib/rules/apple/AppleCommandLineOptions.java
index 5a2ff9d259..af55552e95 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/apple/AppleCommandLineOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/apple/AppleCommandLineOptions.java
@@ -15,7 +15,6 @@
 package com.google.devtools.build.lib.rules.apple;
 
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration.DefaultLabelConverter;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration.LabelConverter;
@@ -333,6 +332,16 @@ public class AppleCommandLineOptions extends FragmentOptions {
   public boolean enableAppleCrosstoolTransition;
 
   @Option(
+      name = "apple_crosstool_in_output_directory_name",
+      defaultValue = "false",
+      documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,
+      effectTags =  {OptionEffectTag.LOADING_AND_ANALYSIS},
+      metadataTags = {OptionMetadataTag.INCOMPATIBLE_CHANGE},
+      help = "If true, all Apple configurations have a different output directory than non-Apple "
+          + "ones")
+  public boolean appleCrosstoolInOutputDirectoryName;
+
+  @Option(
     name = "target_uses_apple_crosstool",
     defaultValue = "false",
     documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,
@@ -358,34 +367,6 @@ public class AppleCommandLineOptions extends FragmentOptions {
   }
 
   /**
-   * Returns the architecture implied by these options.
-   *
-   * <p>In contexts in which a configuration instance is present, prefer {@link
-   * AppleConfiguration#getSingleArchitecture}.
-   */
-  public String getSingleArchitecture() {
-    if (!Strings.isNullOrEmpty(appleSplitCpu)) {
-      return appleSplitCpu;
-    }
-    switch (applePlatformType) {
-      case IOS:
-        if (!iosMultiCpus.isEmpty()) {
-          return iosMultiCpus.get(0);
-        } else {
-          return iosCpu;
-        }
-      case WATCHOS:
-        return watchosCpus.get(0);
-      case TVOS:
-        return tvosCpus.get(0);
-      case MACOS:
-        return macosCpus.get(0);
-      default:
-        throw new IllegalArgumentException("Unhandled platform type " + applePlatformType);
-    }
-  }
-
-  /**
    * Represents the Apple Bitcode mode for compilation steps.
    *
    * <p>Bitcode is an intermediate representation of a compiled program. For many platforms, Apple
diff --git a/src/main/java/com/google/devtools/build/lib/rules/apple/AppleConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/apple/AppleConfiguration.java
index 22333bb41a..530e62ad5c 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/apple/AppleConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/apple/AppleConfiguration.java
@@ -383,24 +383,18 @@ public class AppleConfiguration extends BuildConfiguration.Fragment
     return xcodeConfigLabel;
   }
 
-  /**
-   * Returns the unique identifier distinguishing configurations that are otherwise the same.
-   *
-   * <p>Use this value for situations in which two configurations create two outputs that are the
-   * same but are not collapsed due to their different configuration owners.
-   */
-  public ConfigurationDistinguisher getConfigurationDistinguisher() {
-    return configurationDistinguisher;
-  }
-
   private boolean shouldDistinguishOutputDirectory() {
-    if (configurationDistinguisher == ConfigurationDistinguisher.UNKNOWN) {
-      return false;
-    } else if (configurationDistinguisher == ConfigurationDistinguisher.APPLE_CROSSTOOL
-        && isAppleCrosstoolEnabled()) {
-      return false;
+    if (options.appleCrosstoolInOutputDirectoryName) {
+      return configurationDistinguisher != ConfigurationDistinguisher.UNKNOWN;
     } else {
-      return true;
+      if (configurationDistinguisher == ConfigurationDistinguisher.UNKNOWN) {
+        return false;
+      } else if (configurationDistinguisher == ConfigurationDistinguisher.APPLE_CROSSTOOL
+          && enableAppleCrosstool) {
+        return false;
+      } else {
+        return true;
+      }
     }
   }
 
@@ -439,11 +433,6 @@ public class AppleConfiguration extends BuildConfiguration.Fragment
     return objcProviderFromLinked;
   }
 
-  /** Returns true if {@link AppleCrosstoolTransition} should be applied to every apple rule. */
-  public boolean isAppleCrosstoolEnabled() {
-    return enableAppleCrosstool;
-  }
-
   @Override
   public boolean equals(Object obj) {
     if (this == obj) {