[7.4.0] Support layering_check with C++ path mapping

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

@@ -581,8 +581,8 @@ void addAdditionalInputs(NestedSetBuilder<Artifact> builder) {
     }
   }
 
-  /** @return modules maps from direct dependencies. */
-  public Iterable<Artifact> getDirectModuleMaps() {
+  /** Returns modules maps from direct dependencies. */
+  public ImmutableList<Artifact> getDirectModuleMaps() {
     return directModuleMaps;
   }
 
@@ -595,8 +595,8 @@ DerivedArtifact getSeparateHeaderModule(boolean usePic) {
   }
 
   /**
-   * @return all declared headers of the current module if the current target is compiled as a
-   *     module.
+   * Returns all declared headers of the current module if the current target is compiled as a
+   * module.
    */
   ImmutableList<Artifact> getHeaderModuleSrcs(boolean separateModule) {
     if (separateModule) {
@@ -651,7 +651,7 @@ public static CcCompilationContext createWithExtraHeaderTokens(
         headerTokens.build());
   }
 
-  /** @return the C++ module map of the owner. */
+  /** Returns the C++ module map of the owner. */
   public CppModuleMap getCppModuleMap() {
     return cppModuleMap;
   }
@@ -1154,7 +1154,7 @@ public ImmutableList<E> getMergedResult() {
    * Gathers data about the PIC and no-PIC .pcm files belonging to this context and the associated
    * information about the headers, e.g. modular vs. textual headers and pre-grepped header files.
    *
-   * <p>This also implements a data structure very similar to NestedSet, but chosing slightly
+   * <p>This also implements a data structure very similar to NestedSet, but choosing slightly
    * different trade-offs to account for the specific data stored in here, specifically, we know
    * that there is going to be a single entry in every node of the DAG. Contrary to NestedSet, we
    * reuse memoization data from dependencies to conserve both runtime and memory. Experiments have

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

@@ -22,7 +22,9 @@
 import com.google.devtools.build.docgen.annot.DocCategory;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.CommandLineExpansionException;
+import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.analysis.actions.ActionConstructionContext;
+import com.google.devtools.build.lib.analysis.actions.PathMappers;
 import com.google.devtools.build.lib.analysis.config.BuildConfigurationValue;
 import com.google.devtools.build.lib.analysis.starlark.StarlarkActionFactory;
 import com.google.devtools.build.lib.analysis.starlark.StarlarkRuleContext;
@@ -610,6 +612,7 @@ public void createModuleMapAction(
       Boolean generateSubmodules,
       Boolean withoutExternDependencies)
       throws EvalException {
+    RuleContext ruleContext = actions.getRuleContext();
     ActionConstructionContext actionConstructionContext = actions.getActionConstructionContext();
     actions
         .asActionRegistry(actions)
@@ -629,6 +632,10 @@ public void createModuleMapAction(
                 compiledModule,
                 moduleMapHomeIsCwd,
                 generateSubmodules,
-                withoutExternDependencies));
+                withoutExternDependencies,
+                PathMappers.getOutputPathsMode(ruleContext.getConfiguration()),
+                ruleContext
+                    .getConfiguration()
+                    .modifiedExecutionInfo(ImmutableMap.of(), CppModuleMapAction.MNEMONIC)));
   }
 }

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

@@ -1159,6 +1159,54 @@ public int hashCode() {
     }
   }
 
+  @Immutable
+  private static final class ArtifactSetSequence extends VariableValueAdapter {
+    private final NestedSet<Artifact> values;
+
+    private ArtifactSetSequence(NestedSet<Artifact> values) {
+      Preconditions.checkNotNull(values);
+      this.values = values;
+    }
+
+    @Override
+    public ImmutableList<VariableValue> getSequenceValue(
+        String variableName, PathMapper pathMapper) {
+      ImmutableList<Artifact> valuesList = values.toList();
+      ImmutableList.Builder<VariableValue> sequences =
+          ImmutableList.builderWithExpectedSize(valuesList.size());
+      for (Artifact value : valuesList) {
+        sequences.add(new StringValue(pathMapper.getMappedExecPathString(value)));
+      }
+      return sequences.build();
+    }
+
+    @Override
+    public String getVariableTypeName() {
+      return Sequence.SEQUENCE_VARIABLE_TYPE_NAME;
+    }
+
+    @Override
+    public boolean isTruthy() {
+      return !values.isEmpty();
+    }
+
+    @Override
+    public boolean equals(Object other) {
+      if (this == other) {
+        return true;
+      }
+      if (!(other instanceof ArtifactSetSequence otherArtifacts)) {
+        return false;
+      }
+      return values.shallowEquals(otherArtifacts.values);
+    }
+
+    @Override
+    public int hashCode() {
+      return values.shallowHashCode();
+    }
+  }
+
   /**
    * Single structure value. Be careful not to create sequences of single structures, as the memory
    * overhead is prohibitively big.
@@ -1470,6 +1518,19 @@ public Builder addPathFragmentSequenceVariable(String name, NestedSet<PathFragme
       return this;
     }
 
+    /**
+     * Add a sequence variable that expands {@code name} to {@link Artifact} {@code values}.
+     *
+     * <p>Accepts values as NestedSet. Nested set is stored directly, not cloned, not flattened.
+     */
+    @CanIgnoreReturnValue
+    public Builder addArtifactSequenceVariable(String name, NestedSet<Artifact> values) {
+      checkVariableNotPresentAlready(name);
+      Preconditions.checkNotNull(values, "Cannot set null as a value for variable '%s'", name);
+      variablesMap.put(name, new ArtifactSetSequence(values));
+      return this;
+    }
+
     /**
      * Add a variable built using {@code VariableValueBuilder} api that expands {@code name} to the
      * value returned by the {@code builder}.

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

@@ -163,7 +163,7 @@ public static CcToolchainVariables setupVariablesOrReportRuleError(
       Artifact diagnosticsFile,
       ImmutableList<VariablesExtension> variablesExtensions,
       ImmutableMap<String, String> additionalBuildVariables,
-      Iterable<Artifact> directModuleMaps,
+      ImmutableList<Artifact> directModuleMaps,
       NestedSet<PathFragment> includeDirs,
       NestedSet<PathFragment> quoteIncludeDirs,
       NestedSet<PathFragment> systemIncludeDirs,
@@ -237,7 +237,7 @@ public static CcToolchainVariables setupVariablesOrThrowEvalException(
       Artifact diagnosticsFile,
       ImmutableList<VariablesExtension> variablesExtensions,
       ImmutableMap<String, String> additionalBuildVariables,
-      Iterable<Artifact> directModuleMaps,
+      ImmutableList<Artifact> directModuleMaps,
       NestedSet<String> includeDirs,
       NestedSet<String> quoteIncludeDirs,
       NestedSet<String> systemIncludeDirs,
@@ -303,7 +303,7 @@ private static CcToolchainVariables setupVariables(
       Artifact diagnosticsFile,
       ImmutableList<VariablesExtension> variablesExtensions,
       ImmutableMap<String, String> additionalBuildVariables,
-      Iterable<Artifact> directModuleMaps,
+      ImmutableList<Artifact> directModuleMaps,
       NestedSet<PathFragment> includeDirs,
       NestedSet<PathFragment> quoteIncludeDirs,
       NestedSet<PathFragment> systemIncludeDirs,
@@ -475,7 +475,7 @@ public static void setupCommonVariables(
       String fdoStamp,
       List<VariablesExtension> variablesExtensions,
       Map<String, String> additionalBuildVariables,
-      Iterable<Artifact> directModuleMaps,
+      ImmutableList<Artifact> directModuleMaps,
       ImmutableList<PathFragment> includeDirs,
       ImmutableList<PathFragment> quoteIncludeDirs,
       ImmutableList<PathFragment> systemIncludeDirs,
@@ -509,7 +509,7 @@ private static void setupCommonVariablesInternal(
       String fdoStamp,
       List<VariablesExtension> variablesExtensions,
       Map<String, String> additionalBuildVariables,
-      Iterable<Artifact> directModuleMaps,
+      ImmutableList<Artifact> directModuleMaps,
       NestedSet<PathFragment> includeDirs,
       NestedSet<PathFragment> quoteIncludeDirs,
       NestedSet<PathFragment> systemIncludeDirs,
@@ -528,9 +528,9 @@ private static void setupCommonVariablesInternal(
       buildVariables.addStringVariable(MODULE_NAME.getVariableName(), cppModuleMap.getName());
       buildVariables.addArtifactVariable(
           MODULE_MAP_FILE.getVariableName(), cppModuleMap.getArtifact());
-      buildVariables.addStringSequenceVariable(
+      buildVariables.addArtifactSequenceVariable(
           DEPENDENT_MODULE_MAP_FILES.getVariableName(),
-          Iterables.transform(directModuleMaps, Artifact::getExecPathString));
+          NestedSetBuilder.wrap(Order.STABLE_ORDER, directModuleMaps));
     }
     if (featureConfiguration.isEnabled(CppRuleClasses.USE_HEADER_MODULES)) {
       // Module inputs will be set later when the action is executed.