Expose more fields in C++ Starkark API

This CL exposes APIs related to ExtraLinkTimeLibraries. The necessary fields necessary for re-writing Go that are in the Go package are not exposed here, they should be exposed when the Go rules re-write starts.

Usage is still undocumented and guarded by an internal allow list.

PiperOrigin-RevId: 350572165

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

@@ -31,6 +31,7 @@
 import com.google.devtools.build.lib.packages.SymbolGenerator;
 import com.google.devtools.build.lib.packages.semantics.BuildLanguageOptions;
 import com.google.devtools.build.lib.starlarkbuildapi.cpp.CcLinkingContextApi;
+import com.google.devtools.build.lib.starlarkbuildapi.cpp.ExtraLinkTimeLibraryApi;
 import com.google.devtools.build.lib.starlarkbuildapi.cpp.LinkerInputApi;
 import com.google.devtools.build.lib.starlarkbuildapi.cpp.LinkstampApi;
 import com.google.devtools.build.lib.util.Fingerprint;
@@ -473,6 +474,22 @@ public Depset getStarlarkNonCodeInputs() {
     return Depset.of(Artifact.TYPE, getNonCodeInputs());
   }
 
+  @Override
+  public ExtraLinkTimeLibraryApi getGoLinkCArchiveForStarlark(StarlarkThread thread)
+      throws EvalException {
+    CcModule.checkPrivateStarlarkificationAllowlist(thread);
+    ExtraLinkTimeLibrary goLinkCArchive = null;
+    if (extraLinkTimeLibraries != null) {
+      for (ExtraLinkTimeLibrary extraLibrary : extraLinkTimeLibraries.getExtraLibraries()) {
+        if (goLinkCArchive != null) {
+          throw new EvalException("multiple GoLinkCArchive entries in go_link_c_archive");
+        }
+        goLinkCArchive = extraLibrary;
+      }
+    }
+    return goLinkCArchive;
+  }
+
   public NestedSet<LinkOptions> getUserLinkFlags() {
     NestedSetBuilder<LinkOptions> userLinkFlags = NestedSetBuilder.linkOrder();
     for (LinkerInput linkerInput : linkerInputs.toList()) {

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

@@ -886,6 +886,7 @@ public CcLinkingContext createCcLinkingInfo(
       Object librariesToLinkObject,
       Object userLinkFlagsObject,
       Object nonCodeInputsObject,
+      Object goLinkCArchiveObject,
       StarlarkThread thread)
       throws EvalException {
     if (Starlark.isNullOrNone(linkerInputs)) {
@@ -927,6 +928,15 @@ public CcLinkingContext createCcLinkingInfo(
       CcLinkingContext.Builder ccLinkingContextBuilder = CcLinkingContext.builder();
       ccLinkingContextBuilder.addTransitiveLinkerInputs(
           Depset.noneableCast(linkerInputs, CcLinkingContext.LinkerInput.class, "linker_inputs"));
+      if (checkObjectsBound(goLinkCArchiveObject)) {
+        checkPrivateStarlarkificationAllowlist(thread);
+      }
+      ExtraLinkTimeLibrary goLinkCArchive =
+          convertFromNoneable(goLinkCArchiveObject, /* defaultValue= */ null);
+      if (goLinkCArchive != null) {
+        ccLinkingContextBuilder.setExtraLinkTimeLibraries(
+            ExtraLinkTimeLibraries.builder().add(goLinkCArchive).build());
+      }
 
       @SuppressWarnings("unchecked")
       Sequence<LibraryToLink> librariesToLink = nullIfNone(librariesToLinkObject, Sequence.class);

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

@@ -18,6 +18,7 @@
 import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.packages.RuleClass.ConfiguredTargetFactory.RuleErrorException;
+import com.google.devtools.build.lib.starlarkbuildapi.cpp.ExtraLinkTimeLibraryApi;
 
 /**
  * An extra library to include in a link. The actual library is built at link time.
@@ -29,7 +30,7 @@
  * <p>Any implementations must be immutable (and therefore thread-safe), because this is passed
  * between rules and accessed in a multi-threaded context.
  */
-public interface ExtraLinkTimeLibrary {
+public interface ExtraLinkTimeLibrary extends ExtraLinkTimeLibraryApi {
 
   /** Output of {@link #buildLibraries}. Pair of libraries to link and runtime libraries. */
   class BuildLibraryOutput {

src/main/java/com/google/devtools/build/lib/starlarkbuildapi/cpp/CcLinkingContextApi.java

@@ -18,6 +18,7 @@
 import com.google.devtools.build.lib.collect.nestedset.Depset;
 import com.google.devtools.build.lib.packages.semantics.BuildLanguageOptions;
 import com.google.devtools.build.lib.starlarkbuildapi.FileApi;
+import javax.annotation.Nullable;
 import net.starlark.java.annot.StarlarkBuiltin;
 import net.starlark.java.annot.StarlarkMethod;
 import net.starlark.java.eval.EvalException;
@@ -66,4 +67,12 @@ public interface CcLinkingContextApi<FileT extends FileApi> extends StarlarkValu
 
   @StarlarkMethod(name = "linkstamps", documented = false, useStarlarkThread = true)
   Depset getLinkstampsForStarlark(StarlarkThread thread) throws EvalException;
+
+  @StarlarkMethod(
+      name = "go_link_c_archive",
+      documented = false,
+      allowReturnNones = true,
+      useStarlarkThread = true)
+  @Nullable
+  ExtraLinkTimeLibraryApi getGoLinkCArchiveForStarlark(StarlarkThread thread) throws EvalException;
 }

src/main/java/com/google/devtools/build/lib/starlarkbuildapi/cpp/CcModuleApi.java

@@ -753,12 +753,23 @@ void checkExperimentalStarlarkCcImport(StarlarkActionFactoryT starlarkActionFact
             defaultValue = "None",
             valueWhenDisabled = "None",
             allowedTypes = {@ParamType(type = NoneType.class), @ParamType(type = Sequence.class)}),
+        @Param(
+            name = "go_link_c_archive",
+            documented = false,
+            positional = false,
+            named = true,
+            defaultValue = "unbound",
+            allowedTypes = {
+              @ParamType(type = ExtraLinkTimeLibraryApi.class),
+              @ParamType(type = NoneType.class)
+            })
       })
   LinkingContextT createCcLinkingInfo(
       Object linkerInputs,
       Object librariesToLinkObject,
       Object userLinkFlagsObject,
       Object nonCodeInputs, // <FileT> expected
+      Object goLinkCArchive,
       StarlarkThread thread)
       throws EvalException, InterruptedException;
 

src/main/java/com/google/devtools/build/lib/starlarkbuildapi/cpp/ExtraLinkTimeLibraryApi.java

@@ -0,0 +1,26 @@
+// Copyright 2019 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.starlarkbuildapi.cpp;
+
+import com.google.devtools.build.docgen.annot.DocCategory;
+import net.starlark.java.annot.StarlarkBuiltin;
+import net.starlark.java.eval.StarlarkValue;
+
+/** Used for linking Go into C++ as a single library. */
+@StarlarkBuiltin(
+    name = "ExtraLinkTimeLibrary",
+    documented = false,
+    category = DocCategory.TOP_LEVEL_TYPE)
+public interface ExtraLinkTimeLibraryApi extends StarlarkValue {}

src/main/java/com/google/devtools/build/skydoc/fakebuildapi/cpp/FakeCcModule.java

@@ -214,6 +214,7 @@ public CcLinkingContextApi<FileApi> createCcLinkingInfo(
       Object librariesToLinkObject,
       Object userLinkFlagsObject,
       Object nonCodeInputs,
+      Object goLinkCArchiveObject,
       StarlarkThread thread) {
     return null;
   }

src/test/java/com/google/devtools/build/lib/rules/cpp/StarlarkCcCommonTest.java

@@ -7178,4 +7178,34 @@ public void testExpandedLinkstampApiRaisesError() throws Exception {
       assertThat(e).hasMessageThat().contains("Rule in 'b' cannot use private API");
     }
   }
+
+  @Test
+  public void testExtraLinkTimeLibraryApiRaisesError() throws Exception {
+    scratch.file(
+        "b/BUILD",
+        "load('//b:rule.bzl', 'cc_rule')",
+        "cc_library(name='cc_dep', srcs=['cc_dep.cc'])",
+        "cc_rule(name='foo', cc_dep=':cc_dep')");
+    ImmutableList<String> calls =
+        ImmutableList.of(
+            "cc_common.create_linking_context(linker_inputs=depset([]), go_link_c_archive=None)",
+            "linking_context.go_link_c_archive()");
+    for (String call : calls) {
+      scratch.overwriteFile(
+          "b/rule.bzl",
+          "def _impl(ctx):",
+          "  linking_context = ctx.attr.cc_dep[CcInfo].linking_context",
+          "  " + call,
+          "  return [DefaultInfo()]",
+          "cc_rule = rule(",
+          "  implementation = _impl,",
+          "  attrs = { ",
+          "    'cc_dep': attr.label(),",
+          "  },",
+          ")");
+      invalidatePackages();
+      AssertionError e = assertThrows(AssertionError.class, () -> getConfiguredTarget("//b:foo"));
+      assertThat(e).hasMessageThat().contains("Rule in 'b' cannot use private API");
+    }
+  }
 }