Make the cache in PlatformMappingValue strong instead of weak.

Clear the cache after each command. The overhead of a weak cache's online cleanup performed during lookups shows up in cpu profiles, and we don't need intra-command cleanup.

PiperOrigin-RevId: 680791811
Change-Id: Ibbd062baac40c4c4311c236cc211269a9a3f87b1

src/main/java/com/google/devtools/build/lib/skyframe/BUILD

@@ -270,6 +270,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/analysis:inconsistent_null_config_exception",
         "//src/main/java/com/google/devtools/build/lib/analysis:invalid_visibility_dependency_exception",
         "//src/main/java/com/google/devtools/build/lib/analysis:platform_configuration",
+        "//src/main/java/com/google/devtools/build/lib/analysis:platform_options",
         "//src/main/java/com/google/devtools/build/lib/analysis:required_config_fragments_provider",
         "//src/main/java/com/google/devtools/build/lib/analysis:resolved_toolchain_context",
         "//src/main/java/com/google/devtools/build/lib/analysis:starlark/starlark_build_settings_details_value",
@@ -337,6 +338,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/skyframe/actiongraph/v2:actiongraph_v2",
         "//src/main/java/com/google/devtools/build/lib/skyframe/config",
         "//src/main/java/com/google/devtools/build/lib/skyframe/config:exceptions",
+        "//src/main/java/com/google/devtools/build/lib/skyframe/config:platform_mapping_key",
         "//src/main/java/com/google/devtools/build/lib/skyframe/config:sky_functions",
         "//src/main/java/com/google/devtools/build/lib/skyframe/rewinding",
         "//src/main/java/com/google/devtools/build/lib/skyframe/rewinding:rewindable_graph_inconsistency_receiver",

src/main/java/com/google/devtools/build/lib/skyframe/SkyframeExecutor.java

@@ -98,6 +98,7 @@
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
 import com.google.devtools.build.lib.analysis.ConfiguredTargetValue;
 import com.google.devtools.build.lib.analysis.InconsistentNullConfigException;
+import com.google.devtools.build.lib.analysis.PlatformOptions;
 import com.google.devtools.build.lib.analysis.TargetAndConfiguration;
 import com.google.devtools.build.lib.analysis.TargetConfiguredEvent;
 import com.google.devtools.build.lib.analysis.TopLevelArtifactContext;
@@ -219,6 +220,8 @@
 import com.google.devtools.build.lib.skyframe.config.ParsedFlagsFunction;
 import com.google.devtools.build.lib.skyframe.config.ParsedFlagsValue;
 import com.google.devtools.build.lib.skyframe.config.PlatformMappingFunction;
+import com.google.devtools.build.lib.skyframe.config.PlatformMappingKey;
+import com.google.devtools.build.lib.skyframe.config.PlatformMappingValue;
 import com.google.devtools.build.lib.skyframe.rewinding.ActionRewindStrategy;
 import com.google.devtools.build.lib.skyframe.serialization.analysis.RemoteAnalysisCachingDependenciesProvider;
 import com.google.devtools.build.lib.skyframe.toolchains.RegisteredExecutionPlatformsFunction;
@@ -497,6 +500,8 @@ public abstract class SkyframeExecutor implements WalkableGraphFactory {
 
   private SkyfocusState skyfocusState = SkyfocusState.DISABLED;
 
+  @Nullable private PlatformMappingKey platformMappingKey;
+
   /**
    * Determines the type of hybrid globbing strategy to use when {@link
    * #tracksStateForIncrementality()} is {@code true}. See {@link #getGlobbingStrategy()} for more
@@ -1047,6 +1052,7 @@ public void notifyCommandComplete(ExtendedEventHandler eventHandler) throws Inte
       clearSyscallCache();
       // So that the supplier object can be GC-ed.
       mergedSkyframeAnalysisExecutionSupplier = null;
+      clearPlatformMappingCache();
     }
   }
 
@@ -2196,6 +2202,16 @@ public void clearSyscallCache() {
     syscallCache.clear();
   }
 
+  private void clearPlatformMappingCache() throws InterruptedException {
+    if (platformMappingKey == null) {
+      return;
+    }
+    SkyValue platformMappingValue = memoizingEvaluator.getExistingValue(platformMappingKey);
+    if (platformMappingValue != null) {
+      ((PlatformMappingValue) platformMappingValue).clearMappingCache();
+    }
+  }
+
   public void setConflictCheckingModeInThisBuild(
       ConflictCheckingMode conflictCheckingModeInThisBuild) {
     this.conflictCheckingModeInThisBuild = conflictCheckingModeInThisBuild;
@@ -2640,6 +2656,8 @@ public WorkspaceInfoFromDiff sync(
       String commandName)
       throws InterruptedException, AbruptExitException {
     getActionEnvFromOptions(options.getOptions(CoreOptions.class));
+    var platformOptions = options.getOptions(PlatformOptions.class);
+    platformMappingKey = platformOptions != null ? platformOptions.platformMappingKey : null;
     PrecomputedValue.REPO_ENV.set(injectable(), new LinkedHashMap<>(repoEnvOption));
     RemoteOptions remoteOptions = options.getOptions(RemoteOptions.class);
     setRemoteExecutionEnabled(remoteOptions != null && remoteOptions.isRemoteExecutionEnabled());

src/main/java/com/google/devtools/build/lib/skyframe/config/PlatformMappingValue.java

@@ -71,7 +71,7 @@ public final class PlatformMappingValue implements SkyValue {
     this.platformsToFlags = checkNotNull(platformsToFlags);
     this.flagsToPlatforms = checkNotNull(flagsToPlatforms);
     this.optionsClasses = checkNotNull(optionsClasses);
-    this.mappingCache = Caffeine.newBuilder().weakKeys().build(this::computeMapping);
+    this.mappingCache = Caffeine.newBuilder().build(this::computeMapping);
   }
 
   /**
@@ -109,6 +109,11 @@ public BuildConfigurationKey map(BuildOptions original) throws OptionsParsingExc
     }
   }
 
+  /** Clears the mapping cache to save memory. */
+  public void clearMappingCache() {
+    mappingCache.invalidateAll();
+  }
+
   private BuildConfigurationKey computeMapping(BuildOptions originalOptions)
       throws OptionsParsingException {
     if (originalOptions.hasNoConfig()) {