Add the option to have non-interface dependencies. This can greatly speed up

builds with C++ modules as modules can be built without waiting on dependencies
that are only required for the module's implementation.

--
MOS_MIGRATED_REVID=120119435

5 files changed, 89 insertions, 29 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcLibraryHelper.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcLibraryHelper.java
index 9f8f98d46c..dc7f035353 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcLibraryHelper.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcLibraryHelper.java
@@ -201,7 +201,8 @@ public final class CcLibraryHelper {
   @Nullable private Pattern nocopts;
   private final List<String> linkopts = new ArrayList<>();
   private final Set<String> defines = new LinkedHashSet<>();
-  private final List<TransitiveInfoCollection> deps = new ArrayList<>();
+  private final List<TransitiveInfoCollection> implementationDeps = new ArrayList<>();
+  private final List<TransitiveInfoCollection> interfaceDeps = new ArrayList<>();
   private final List<Artifact> linkstamps = new ArrayList<>();
   private final List<Artifact> prerequisites = new ArrayList<>();
   private final List<PathFragment> looseIncludeDirs = new ArrayList<>();
@@ -513,7 +514,26 @@ public final class CcLibraryHelper {
       Preconditions.checkArgument(dep.getConfiguration() == null
           || configuration.equalsOrIsSupersetOf(dep.getConfiguration()),
           "dep " + dep.getLabel() + " has a different config than " + ruleContext.getLabel());
-      this.deps.add(dep);
+      this.implementationDeps.add(dep);
+      this.interfaceDeps.add(dep);
+    }
+    return this;
+  }
+
+  /**
+   * Similar to @{link addDeps}, but adds the given targets as implementation dependencies.
+   * Implementation dependencies are required to actually build a target, but are not required to
+   * build the target's interface, e.g. header module. Thus, implementation dependencies are always
+   * a superset of interface dependencies. Whatever is required to build the interface is also
+   * required to build the implementation.
+   */
+  public CcLibraryHelper addImplementationDeps(Iterable<? extends TransitiveInfoCollection> deps) {
+    for (TransitiveInfoCollection dep : deps) {
+      Preconditions.checkArgument(
+          dep.getConfiguration() == null
+              || configuration.equalsOrIsSupersetOf(dep.getConfiguration()),
+          "dep " + dep.getLabel() + " has a different config than " + ruleContext.getLabel());
+      this.implementationDeps.add(dep);
     }
     return this;
   }
@@ -727,15 +747,26 @@ public final class CcLibraryHelper {
 
     if (checkDepsGenerateCpp) {
       for (LanguageDependentFragment dep :
-          AnalysisUtils.getProviders(deps, LanguageDependentFragment.class)) {
+          AnalysisUtils.getProviders(implementationDeps, LanguageDependentFragment.class)) {
         LanguageDependentFragment.Checker.depSupportsLanguage(
             ruleContext, dep, CppRuleClasses.LANGUAGE);
       }
     }
 
     CppModel model = initializeCppModel();
-    CppCompilationContext cppCompilationContext = initializeCppCompilationContext(model);
+    CppCompilationContext cppCompilationContext =
+        initializeCppCompilationContext(model, /*forInterface=*/ false);
     model.setContext(cppCompilationContext);
+
+    // If we actually have different interface deps, we need a separate compilation context
+    // for the interface. Otherwise, we can just re-use the normal cppCompilationContext.
+    CppCompilationContext interfaceCompilationContext = cppCompilationContext;
+    // As implemenationDeps is a superset of interfaceDeps, comparing the size proves equality.
+    if (implementationDeps.size() != interfaceDeps.size()) {
+      interfaceCompilationContext = initializeCppCompilationContext(model, /*forInterface=*/ true);
+    }
+    model.setInterfaceContext(interfaceCompilationContext);
+
     boolean compileHeaderModules = featureConfiguration.isEnabled(CppRuleClasses.HEADER_MODULES);
     Preconditions.checkState(
         !compileHeaderModules || cppCompilationContext.getCppModuleMap() != null,
@@ -781,7 +812,8 @@ public final class CcLibraryHelper {
           .build();
     }
 
-    DwoArtifactsCollector dwoArtifacts = DwoArtifactsCollector.transitiveCollector(ccOutputs, deps);
+    DwoArtifactsCollector dwoArtifacts =
+        DwoArtifactsCollector.transitiveCollector(ccOutputs, implementationDeps);
     Runfiles cppStaticRunfiles = collectCppRunfiles(ccLinkingOutputs, true);
     Runfiles cppSharedRunfiles = collectCppRunfiles(ccLinkingOutputs, false);
 
@@ -791,7 +823,7 @@ public final class CcLibraryHelper {
         new LinkedHashMap<>();
     providers.put(CppRunfilesProvider.class,
         new CppRunfilesProvider(cppStaticRunfiles, cppSharedRunfiles));
-    providers.put(CppCompilationContext.class, cppCompilationContext);
+    providers.put(CppCompilationContext.class, interfaceCompilationContext);
     providers.put(CppDebugFileProvider.class, new CppDebugFileProvider(
         dwoArtifacts.getDwoArtifacts(), dwoArtifacts.getPicDwoArtifacts()));
     providers.put(TransitiveLipoInfoProvider.class, collectTransitiveLipoInfo(ccOutputs));
@@ -855,9 +887,10 @@ public final class CcLibraryHelper {
   /**
    * Create context for cc compile action from generated inputs.
    */
-  private CppCompilationContext initializeCppCompilationContext(CppModel model) {
+  private CppCompilationContext initializeCppCompilationContext(
+      CppModel model, boolean forInterface) {
     CppCompilationContext.Builder contextBuilder =
-        new CppCompilationContext.Builder(ruleContext);
+        new CppCompilationContext.Builder(ruleContext, forInterface);
 
     // Setup the include path; local include directories come before those inherited from deps or
     // from the toolchain; in case of aliasing (same include file found on different entries),
@@ -881,7 +914,8 @@ public final class CcLibraryHelper {
     }
 
     contextBuilder.mergeDependentContexts(
-        AnalysisUtils.getProviders(deps, CppCompilationContext.class));
+        AnalysisUtils.getProviders(
+            forInterface ? interfaceDeps : implementationDeps, CppCompilationContext.class));
     CppHelper.mergeToolchainDependentContext(ruleContext, contextBuilder);
 
     // But defines come after those inherited from deps.
@@ -952,13 +986,13 @@ public final class CcLibraryHelper {
    * Creates context for cc compile action from generated inputs.
    */
   public CppCompilationContext initializeCppCompilationContext() {
-    return initializeCppCompilationContext(initializeCppModel());
+    return initializeCppCompilationContext(initializeCppModel(), /*forInterface=*/ false);
   }
 
   private Iterable<CppModuleMap> collectModuleMaps() {
     // Cpp module maps may be null for some rules. We filter the nulls out at the end.
     List<CppModuleMap> result = new ArrayList<>();
-    Iterables.addAll(result, Iterables.transform(deps, CPP_DEPS_TO_MODULES));
+    Iterables.addAll(result, Iterables.transform(interfaceDeps, CPP_DEPS_TO_MODULES));
     if (ruleContext.getRule().getAttributeDefinition(":stl") != null) {
       CppCompilationContext stl =
           ruleContext.getPrerequisite(":stl", Mode.TARGET, CppCompilationContext.class);
@@ -990,7 +1024,7 @@ public final class CcLibraryHelper {
     }
 
     for (TransitiveLipoInfoProvider dep :
-        AnalysisUtils.getProviders(deps, TransitiveLipoInfoProvider.class)) {
+        AnalysisUtils.getProviders(implementationDeps, TransitiveLipoInfoProvider.class)) {
       scannableBuilder.addTransitive(dep.getTransitiveIncludeScannables());
     }
 
@@ -1004,8 +1038,8 @@ public final class CcLibraryHelper {
   private Runfiles collectCppRunfiles(
       CcLinkingOutputs ccLinkingOutputs, boolean linkingStatically) {
     Runfiles.Builder builder = new Runfiles.Builder(ruleContext.getWorkspaceName());
-    builder.addTargets(deps, RunfilesProvider.DEFAULT_RUNFILES);
-    builder.addTargets(deps, CppRunfilesProvider.runfilesFunction(linkingStatically));
+    builder.addTargets(implementationDeps, RunfilesProvider.DEFAULT_RUNFILES);
+    builder.addTargets(implementationDeps, CppRunfilesProvider.runfilesFunction(linkingStatically));
     // Add the shared libraries to the runfiles.
     builder.addArtifacts(ccLinkingOutputs.getLibrariesForRunfiles(linkingStatically));
     return builder.build();
@@ -1019,7 +1053,7 @@ public final class CcLibraryHelper {
       protected void collect(CcLinkParams.Builder builder, boolean linkingStatically,
           boolean linkShared) {
         builder.addLinkstamps(linkstamps, cppCompilationContext);
-        builder.addTransitiveTargets(deps,
+        builder.addTransitiveTargets(implementationDeps,
             CcLinkParamsProvider.TO_LINK_PARAMS, CcSpecificLinkParamsProvider.TO_LINK_PARAMS);
         if (!neverlink) {
           builder.addLibraries(ccLinkingOutputs.getPreferredLibraries(linkingStatically,
@@ -1033,8 +1067,8 @@ public final class CcLibraryHelper {
   private NestedSet<LinkerInput> collectNativeCcLibraries(CcLinkingOutputs ccLinkingOutputs) {
     NestedSetBuilder<LinkerInput> result = NestedSetBuilder.linkOrder();
     result.addAll(ccLinkingOutputs.getDynamicLibraries());
-    for (CcNativeLibraryProvider dep : AnalysisUtils.getProviders(
-        deps, CcNativeLibraryProvider.class)) {
+    for (CcNativeLibraryProvider dep :
+        AnalysisUtils.getProviders(implementationDeps, CcNativeLibraryProvider.class)) {
       result.addTransitive(dep.getTransitiveCcNativeLibraries());
     }
 
@@ -1051,7 +1085,7 @@ public final class CcLibraryHelper {
 
     NestedSetBuilder<Artifact> builder = NestedSetBuilder.stableOrder();
     for (CcExecutionDynamicLibrariesProvider dep :
-        AnalysisUtils.getProviders(deps, CcExecutionDynamicLibrariesProvider.class)) {
+        AnalysisUtils.getProviders(implementationDeps, CcExecutionDynamicLibrariesProvider.class)) {
       builder.addTransitive(dep.getExecutionDynamicLibraryArtifacts());
     }
     return builder.isEmpty()
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeatures.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeatures.java
index b7bf3f48cc..41124222bb 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeatures.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeatures.java
@@ -999,7 +999,7 @@ public class CcToolchainFeatures implements Serializable {
     /**
      * @return whether the given {@code feature} is enabled.
      */
-    boolean isEnabled(String feature) {
+    public boolean isEnabled(String feature) {
       return enabledFeatureNames.contains(feature);
     }
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompilationContext.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompilationContext.java
index 4afd941c0b..af3bbba851 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompilationContext.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompilationContext.java
@@ -614,7 +614,7 @@ public final class CppCompilationContext implements TransitiveInfoProvider {
    * Builder class for {@link CppCompilationContext}.
    */
   public static class Builder {
-    private String purpose = "cpp_compilation_prerequisites";
+    private String purpose;
     private final Set<Artifact> compilationPrerequisites = new LinkedHashSet<>();
     private final Set<PathFragment> includeDirs = new LinkedHashSet<>();
     private final Set<PathFragment> quoteIncludeDirs = new LinkedHashSet<>();
@@ -654,7 +654,17 @@ public final class CppCompilationContext implements TransitiveInfoProvider {
      * Creates a new builder for a {@link CppCompilationContext} instance.
      */
     public Builder(RuleContext ruleContext) {
+      this(ruleContext, /*forInterface=*/ false);
+    }
+
+    /**
+     * Creates a new builder for a {@link CppCompilationContext} instance.
+     *
+     * @param forInterface if true, this context is designated for the compilation of an interface.
+     */
+    public Builder(RuleContext ruleContext, boolean forInterface) {
       this.ruleContext = ruleContext;
+      this.purpose = forInterface ? "cpp_interface_prerequisites" : "cpp_compilation_prerequisites";
     }
 
     /**
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppModel.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppModel.java
index 0132191c30..579e8492d8 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppModel.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppModel.java
@@ -61,6 +61,7 @@ public final class CppModel {
 
   // compile model
   private CppCompilationContext context;
+  private CppCompilationContext interfaceContext;
   private final List<Pair<Artifact, Label>> sourceFiles = new ArrayList<>();
   private final List<String> copts = new ArrayList<>();
   private final List<PathFragment> additionalIncludes = new ArrayList<>();
@@ -121,6 +122,15 @@ public final class CppModel {
     this.context = context;
     return this;
   }
+  
+  /**
+   * Sets the compilation context, i.e. include directories and allowed header files inclusions, for
+   * the compilation of this model's interface, e.g. header module.
+   */
+  public CppModel setInterfaceContext(CppCompilationContext context) {
+    this.interfaceContext = context;
+    return this;
+  }
 
   /**
    * Adds a single source file to be compiled. Note that this should only be called for primary
@@ -279,9 +289,10 @@ public final class CppModel {
    * Returns a {@code CppCompileActionBuilder} with the common fields for a C++ compile action
    * being initialized.
    */
-  private CppCompileActionBuilder initializeCompileAction(Artifact sourceArtifact,
-      Label sourceLabel) {
-    CppCompileActionBuilder builder = createCompileActionBuilder(sourceArtifact, sourceLabel);
+  private CppCompileActionBuilder initializeCompileAction(
+      Artifact sourceArtifact, Label sourceLabel, boolean forInterface) {
+    CppCompileActionBuilder builder =
+        createCompileActionBuilder(sourceArtifact, sourceLabel, forInterface);
     if (nocopts != null) {
       builder.addNocopts(nocopts);
     }
@@ -395,7 +406,8 @@ public final class CppModel {
       Artifact moduleMapArtifact = context.getCppModuleMap().getArtifact();
       Label moduleMapLabel = Label.parseAbsoluteUnchecked(context.getCppModuleMap().getName());
       PathFragment outputName = getObjectOutputPath(moduleMapArtifact, objectDir);
-      CppCompileActionBuilder builder = initializeCompileAction(moduleMapArtifact, moduleMapLabel);
+      CppCompileActionBuilder builder =
+          initializeCompileAction(moduleMapArtifact, moduleMapLabel, /*forInterface=*/ true);
 
       // A header module compile action is just like a normal compile action, but:
       // - the compiled source file is the module map
@@ -408,7 +420,8 @@ public final class CppModel {
       Artifact sourceArtifact = source.getFirst();
       Label sourceLabel = source.getSecond();
       PathFragment outputName = getObjectOutputPath(sourceArtifact, objectDir);
-      CppCompileActionBuilder builder = initializeCompileAction(sourceArtifact, sourceLabel);
+      CppCompileActionBuilder builder =
+          initializeCompileAction(sourceArtifact, sourceLabel, /*forInterface=*/ false);
       
       if (CppFileTypes.CPP_HEADER.matches(source.first.getExecPath())) {
         createHeaderAction(outputName, result, env, builder);
@@ -734,13 +747,11 @@ public final class CppModel {
    * crosstool inputs, output and dotd file names, compilation context and copts.
    */
   private CppCompileActionBuilder createCompileActionBuilder(
-      Artifact source, Label label) {
+      Artifact source, Label label, boolean forInterface) {
     CppCompileActionBuilder builder = new CppCompileActionBuilder(
         ruleContext, source, label);
 
-    builder
-        .setContext(context)
-        .addCopts(copts);
+    builder.setContext(forInterface ? interfaceContext : context).addCopts(copts);
     return builder;
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppRuleClasses.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppRuleClasses.java
index 77a9719923..2d71008e23 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppRuleClasses.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppRuleClasses.java
@@ -88,6 +88,11 @@ public class CppRuleClasses {
    * A string constant for the preprocess_headers feature.
    */
   public static final String PREPROCESS_HEADERS = "preprocess_headers";
+  
+  /**
+   * A string constant for the disable_pbh feature.
+   */
+  public static final String DISABLE_PBH = "disable_pbh";
 
   /**
    * A string constant for the module_maps feature; this is a precondition to the layering_check and