Enable Apple Silicon iOS simulator support via use of new CPU type. T…

…his will be removed in favor of platforms once moved onto the new toolchain resolution system.

PiperOrigin-RevId: 391596112

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

@@ -67,9 +67,13 @@ public class AppleConfiguration extends Fragment implements AppleConfigurationAp
    */
   public static final String APPLE_SDK_PLATFORM_ENV_NAME = "APPLE_SDK_PLATFORM";
 
-  /** Prefix for iOS cpu values. */
+  /** Prefix for iOS cpu values */
   public static final String IOS_CPU_PREFIX = "ios_";
 
+  // TODO(b/180572694): Remove after platforms based toolchain resolution supported.
+  /** Prefix for forced iOS simulator cpu values */
+  public static final String IOS_FORCED_SIMULATOR_CPU_PREFIX = "sim_";
+
   /** Default cpu for iOS builds. */
   @VisibleForTesting static final String DEFAULT_IOS_CPU = "x86_64";
 
@@ -214,16 +218,33 @@ public String getIosCpu() {
    */
   @Override
   public String getSingleArchitecture() {
-    return getSingleArchitecture(applePlatformType, appleCpus);
+    return getSingleArchitecture(applePlatformType, appleCpus, /* removeSimPrefix= */ true);
   }
 
-  private static String getSingleArchitecture(PlatformType applePlatformType, AppleCpus appleCpus) {
+  private static String getSingleArchitecture(
+      PlatformType applePlatformType, AppleCpus appleCpus, boolean removeSimPrefix) {
+    // The removeSimPrefix argument is necessary due to a simulator and device both using arm64
+    // architecture. In the case of Starlark asking for the architecture, we should return the
+    // actual architecture (arm64) but in other cases in this class what we actually want is the
+    // CPU without the ios prefix (e.g. sim_arm64). This parameter is provided in the private method
+    // so that internal to this class we are able to use both without duplicating retrieval logic.
+    // TODO(b/180572694): Remove removeSimPrefix parameter once platforms are used instead of CPU
     if (!Strings.isNullOrEmpty(appleCpus.appleSplitCpu())) {
-      return appleCpus.appleSplitCpu();
+      String cpu = appleCpus.appleSplitCpu();
+      if (removeSimPrefix && cpu.startsWith(IOS_FORCED_SIMULATOR_CPU_PREFIX)) {
+        cpu = cpu.substring(IOS_FORCED_SIMULATOR_CPU_PREFIX.length());
+      }
+      return cpu;
     }
     switch (applePlatformType) {
       case IOS:
-        return Iterables.getFirst(appleCpus.iosMultiCpus(), appleCpus.iosCpu());
+        {
+          String cpu = Iterables.getFirst(appleCpus.iosMultiCpus(), appleCpus.iosCpu());
+          if (removeSimPrefix && cpu.startsWith(IOS_FORCED_SIMULATOR_CPU_PREFIX)) {
+            cpu = cpu.substring(IOS_FORCED_SIMULATOR_CPU_PREFIX.length());
+          }
+          return cpu;
+        }
       case WATCHOS:
         return appleCpus.watchosCpus().get(0);
       case TVOS:
@@ -292,7 +313,9 @@ public List<String> getMultiArchitectures(PlatformType platformType) {
    */
   @Override
   public ApplePlatform getSingleArchPlatform() {
-    return ApplePlatform.forTarget(applePlatformType, getSingleArchitecture());
+    return ApplePlatform.forTarget(
+        applePlatformType,
+        getSingleArchitecture(applePlatformType, appleCpus, /* removeSimPrefix= */ false));
   }
 
   /**
@@ -394,7 +417,8 @@ public static AppleBitcodeMode getAppleBitcodeMode(
       PlatformType applePlatformType,
       AppleCpus appleCpus,
       EnumMap<ApplePlatform.PlatformType, AppleBitcodeMode> platformBitcodeModes) {
-    String architecture = getSingleArchitecture(applePlatformType, appleCpus);
+    String architecture =
+        getSingleArchitecture(applePlatformType, appleCpus, /* removeSimPrefix= */ false);
     String cpuString = ApplePlatform.cpuStringForTarget(applePlatformType, architecture);
     if (ApplePlatform.isApplePlatform(cpuString)) {
       ApplePlatform platform = ApplePlatform.forTarget(applePlatformType, architecture);

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

@@ -41,8 +41,9 @@ public enum ApplePlatform implements ApplePlatformApi {
   WATCHOS_SIMULATOR("watchos_simulator", "WatchSimulator", PlatformType.WATCHOS, false),
   CATALYST("catalyst", "MacOSX", PlatformType.CATALYST, true);
 
+  // TODO(b/180572694): Remove ios_sim_arm64 after platforms based toolchain resolution supported.
   private static final ImmutableSet<String> IOS_SIMULATOR_TARGET_CPUS =
-      ImmutableSet.of("ios_x86_64", "ios_i386");
+      ImmutableSet.of("ios_x86_64", "ios_i386", "ios_sim_arm64");
   private static final ImmutableSet<String> IOS_DEVICE_TARGET_CPUS =
       ImmutableSet.of("ios_armv6", "ios_arm64", "ios_armv7", "ios_armv7s", "ios_arm64e");
   private static final ImmutableSet<String> WATCHOS_SIMULATOR_TARGET_CPUS =