Add an option to remove the toolchain identifier from the name of the…

… output directory.

This will probably need some more work so that there are no name clashes with e.g. Android output directory names, but let's take one step at a time.

RELNOTES: None.
PiperOrigin-RevId: 162328750

src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java

@@ -226,6 +226,11 @@ ImmutableList<String> evaluate(Iterable<String> features) {
   private final Label crosstoolTop;
   private final String hostSystemName;
   private final String compiler;
+  // TODO(lberki): desiredCpu *should* be always the same as targetCpu, except that we don't check
+  // that the CPU we get from the toolchain matches BuildConfiguration.Options.cpu . So we store
+  // it here so that the output directory doesn't depend on the CToolchain. When we will eventually
+  // verify that the two are the same, we can remove one of desiredCpu and targetCpu.
+  private final String desiredCpu;
   private final String targetCpu;
   private final String targetSystemName;
   private final String targetLibc;
@@ -313,12 +318,17 @@ ImmutableList<String> evaluate(Iterable<String> features) {
    */
   private final boolean lipoContextCollector;
 
+  /** If true, add the toolchain identifier to the name of the output directory. */
+  private final boolean toolchainIdInOutputDirectory;
+
   protected CppConfiguration(CppConfigurationParameters params)
       throws InvalidConfigurationException {
     CrosstoolConfig.CToolchain toolchain = params.toolchain;
     cppOptions = params.cppOptions;
+    this.toolchainIdInOutputDirectory = cppOptions.toolchainIdInOutputDirectory;
     this.hostSystemName = toolchain.getHostSystemName();
     this.compiler = toolchain.getCompiler();
+    this.desiredCpu = Preconditions.checkNotNull(params.commonOptions.cpu);
     this.targetCpu = toolchain.getTargetCpu();
     this.lipoMode = cppOptions.getLipoMode();
     this.targetSystemName = toolchain.getTargetSystemName();
@@ -2068,7 +2078,9 @@ public String getOutputDirectoryName() {
     } else {
       lipoSuffix = "";
     }
-    return toolchainIdentifier + lipoSuffix;
+    String toolchainPrefix = toolchainIdInOutputDirectory
+        ? toolchainIdentifier : desiredCpu;
+    return toolchainPrefix + lipoSuffix;
   }
 
   @Override

src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java

@@ -540,6 +540,16 @@ public LipoMode getLipoMode() {
    */
   public Label lipoContextForBuild;
 
+  @Option(
+    name = "experimental_toolchain_id_in_output_directory",
+    defaultValue = "true",
+    category = "semantics",
+    documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,
+    effectTags = OptionEffectTag.AFFECTS_OUTPUTS,
+    help = "Whether to embed the name of the C++ toolchain in the name of the output directory"
+  )
+  public boolean toolchainIdInOutputDirectory;
+
   /**
    * Returns the --lipo_context value if LIPO is specified and active for this configuration,
    * null otherwise.
@@ -840,6 +850,11 @@ public FragmentOptions getHost(boolean fallback) {
       }
     }
 
+    // the name of the output directory for the host configuration is forced to be "host" in
+    // BuildConfiguration.Options#getHost(), but let's be prudent here in case someone ends up
+    // removing that
+    host.toolchainIdInOutputDirectory = toolchainIdInOutputDirectory;
+
     // hostLibcTop doesn't default to the target's libcTop.
     // Only an explicit command-line option will change it.
     // The default is whatever the host's crosstool (which might have been specified