Only allocate some formerly frequently allocated PathFragment objects once.

This reduces both gc churn and retained memory usage.

PiperOrigin-RevId: 154718782

2 files changed, 69 insertions, 15 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java b/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
index f47b38d006..681c88b45a 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
@@ -1260,7 +1260,18 @@ public final class RuleContext extends TargetContext
    * <p>For example "pkg/dir/name" -> "pkg/&lt;fragment>/rule/dir/name.
    */
   public final PathFragment getUniqueDirectory(String fragment) {
-    return AnalysisUtils.getUniqueDirectory(getLabel(), PathFragment.create(fragment));
+    return getUniqueDirectory(PathFragment.create(fragment));
+  }
+
+  /**
+   * Returns a path fragment qualified by the rule name and unique fragment to
+   * disambiguate artifacts produced from the source file appearing in
+   * multiple rules.
+   *
+   * <p>For example "pkg/dir/name" -> "pkg/&lt;fragment>/rule/dir/name.
+   */
+  public final PathFragment getUniqueDirectory(PathFragment fragment) {
+    return AnalysisUtils.getUniqueDirectory(getLabel(), fragment);
   }
 
   /**
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
index 9e11f94270..3273a6d3e6 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
@@ -1168,7 +1168,7 @@ public final class BuildConfiguration {
     INCLUDE(BlazeDirectories.RELATIVE_INCLUDE_DIR),
     OUTPUT(false);
 
-    private final String name;
+    private final PathFragment nameFragment;
     private final boolean middleman;
 
     /**
@@ -1177,12 +1177,12 @@ public final class BuildConfiguration {
      * @param isMiddleman whether the root should be a middleman root or a "normal" derived root.
      */
     OutputDirectory(boolean isMiddleman) {
-      this.name = "";
+      this.nameFragment = PathFragment.EMPTY_FRAGMENT;
       this.middleman = isMiddleman;
     }
 
     OutputDirectory(String name) {
-      this.name = name;
+      this.nameFragment = PathFragment.create(name);
       this.middleman = false;
     }
 
@@ -1198,16 +1198,29 @@ public final class BuildConfiguration {
       }
       // e.g., [[execroot/repo1]/bazel-out/config/bin]
       return INTERNER.intern(
-          Root.asDerivedRoot(execRoot, outputDir.getRelative(name), repositoryName.isMain()));
+          Root.asDerivedRoot(
+              execRoot,
+              outputDir.getRelative(nameFragment),
+              repositoryName.isMain()));
     }
   }
 
-  // "Cache" of roots, so we don't keep around thousands of copies of the same root.
-  private static Interner<Root> INTERNER = Interners.newWeakInterner();
-
   private final BlazeDirectories directories;
   private final String outputDirName;
 
+  // We intern the roots for non-main repositories, so we don't keep around thousands of copies of
+  // the same root.
+  private static Interner<Root> INTERNER = Interners.newWeakInterner();
+
+  // We precompute the roots for the main repository, since that's the common case.
+  private final Root outputDirectoryForMainRepository;
+  private final Root binDirectoryForMainRepository;
+  private final Root includeDirectoryForMainRepository;
+  private final Root genfilesDirectoryForMainRepository;
+  private final Root coverageDirectoryForMainRepository;
+  private final Root testlogsDirectoryForMainRepository;
+  private final Root middlemanDirectoryForMainRepository;
+
   /** If false, AnalysisEnviroment doesn't register any actions created by the ConfiguredTarget. */
   private final boolean actionsEnabled;
 
@@ -1444,6 +1457,22 @@ public final class BuildConfiguration {
     this.mnemonic = buildMnemonic();
     this.outputDirName = (options.outputDirectoryName != null)
         ? options.outputDirectoryName : mnemonic;
+
+    this.outputDirectoryForMainRepository =
+        OutputDirectory.OUTPUT.getRoot(RepositoryName.MAIN, outputDirName, directories);
+    this.binDirectoryForMainRepository =
+        OutputDirectory.BIN.getRoot(RepositoryName.MAIN, outputDirName, directories);
+    this.includeDirectoryForMainRepository =
+        OutputDirectory.INCLUDE.getRoot(RepositoryName.MAIN, outputDirName, directories);
+    this.genfilesDirectoryForMainRepository =
+        OutputDirectory.GENFILES.getRoot(RepositoryName.MAIN, outputDirName, directories);
+    this.coverageDirectoryForMainRepository =
+        OutputDirectory.COVERAGE.getRoot(RepositoryName.MAIN, outputDirName, directories);
+    this.testlogsDirectoryForMainRepository =
+        OutputDirectory.TESTLOGS.getRoot(RepositoryName.MAIN, outputDirName, directories);
+    this.middlemanDirectoryForMainRepository =
+        OutputDirectory.MIDDLEMAN.getRoot(RepositoryName.MAIN, outputDirName, directories);
+
     this.platformName = buildPlatformName();
 
     this.shellExecutable = computeShellExecutable();
@@ -2068,7 +2097,9 @@ public final class BuildConfiguration {
    * Returns the output directory for this build configuration.
    */
   public Root getOutputDirectory(RepositoryName repositoryName) {
-    return OutputDirectory.OUTPUT.getRoot(repositoryName, outputDirName, directories);
+    return repositoryName.equals(RepositoryName.MAIN)
+        ? outputDirectoryForMainRepository
+        : OutputDirectory.OUTPUT.getRoot(repositoryName, outputDirName, directories);
   }
 
   /**
@@ -2087,7 +2118,9 @@ public final class BuildConfiguration {
    * repositories (external) but will need to be fixed.
    */
   public Root getBinDirectory(RepositoryName repositoryName) {
-    return OutputDirectory.BIN.getRoot(repositoryName, outputDirName, directories);
+    return repositoryName.equals(RepositoryName.MAIN)
+        ? binDirectoryForMainRepository
+        : OutputDirectory.BIN.getRoot(repositoryName, outputDirName, directories);
   }
 
   /**
@@ -2101,7 +2134,9 @@ public final class BuildConfiguration {
    * Returns the include directory for this build configuration.
    */
   public Root getIncludeDirectory(RepositoryName repositoryName) {
-    return OutputDirectory.INCLUDE.getRoot(repositoryName, outputDirName, directories);
+    return repositoryName.equals(RepositoryName.MAIN)
+        ? includeDirectoryForMainRepository
+        : OutputDirectory.INCLUDE.getRoot(repositoryName, outputDirName, directories);
   }
 
   /**
@@ -2114,7 +2149,9 @@ public final class BuildConfiguration {
   }
 
   public Root getGenfilesDirectory(RepositoryName repositoryName) {
-    return OutputDirectory.GENFILES.getRoot(repositoryName, outputDirName, directories);
+    return repositoryName.equals(RepositoryName.MAIN)
+        ? genfilesDirectoryForMainRepository
+        : OutputDirectory.GENFILES.getRoot(repositoryName, outputDirName, directories);
   }
 
   /**
@@ -2123,14 +2160,18 @@ public final class BuildConfiguration {
    * needed for Jacoco's coverage reporting tools.
    */
   public Root getCoverageMetadataDirectory(RepositoryName repositoryName) {
-    return OutputDirectory.COVERAGE.getRoot(repositoryName, outputDirName, directories);
+    return repositoryName.equals(RepositoryName.MAIN)
+        ? coverageDirectoryForMainRepository
+        : OutputDirectory.COVERAGE.getRoot(repositoryName, outputDirName, directories);
   }
 
   /**
    * Returns the testlogs directory for this build configuration.
    */
   public Root getTestLogsDirectory(RepositoryName repositoryName) {
-    return OutputDirectory.TESTLOGS.getRoot(repositoryName, outputDirName, directories);
+    return repositoryName.equals(RepositoryName.MAIN)
+        ? testlogsDirectoryForMainRepository
+        : OutputDirectory.TESTLOGS.getRoot(repositoryName, outputDirName, directories);
   }
 
   /**
@@ -2157,7 +2198,9 @@ public final class BuildConfiguration {
    * Returns the internal directory (used for middlemen) for this build configuration.
    */
   public Root getMiddlemanDirectory(RepositoryName repositoryName) {
-    return OutputDirectory.MIDDLEMAN.getRoot(repositoryName, outputDirName, directories);
+    return repositoryName.equals(RepositoryName.MAIN)
+        ? middlemanDirectoryForMainRepository
+        : OutputDirectory.MIDDLEMAN.getRoot(repositoryName, outputDirName, directories);
   }
 
   public boolean getAllowRuntimeDepsOnNeverLink() {