[8.1.0] Add environment variables to LTO backend actions. (#25242)

PiperOrigin-RevId: 700351238
Change-Id: If9e0686bee0756b0af56cda91ac70d184858fd72

Commit
0937e35

Co-authored-by: Googler <[email protected]>

Author: bazel-io

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

@@ -165,6 +165,7 @@ public final class LtoBackendArtifacts implements LtoBackendArtifactsApi<Artifac
                         linkActionConstruction.getConfig().isSiblingRepositoryLayout()),
                     ".dwo"));
       }
+      addEnvironmentVariables(builder, buildVariables, featureConfiguration);
       scheduleLtoBackendAction(
           builder,
           buildVariables,
@@ -329,6 +330,20 @@ private static void addOutputsToLtoBackendActionBuilder(
     }
   }
 
+  private static void addEnvironmentVariables(
+      LtoBackendAction.Builder builder,
+      CcToolchainVariables buildVariables,
+      FeatureConfiguration featureConfiguration)
+      throws EvalException {
+    try {
+      builder.setEnvironment(
+          featureConfiguration.getEnvironmentVariables(
+              CppActionNames.LTO_BACKEND, buildVariables, PathMapper.NOOP));
+    } catch (ExpansionException e) {
+      throw new EvalException(e.getMessage());
+    }
+  }
+
   private static void addCommandLineToLtoBackendActionBuilder(
       LtoBackendAction.Builder builder,
       FeatureConfiguration featureConfiguration,

src/test/java/com/google/devtools/build/lib/analysis/mock/cc_toolchain_config.bzl

@@ -369,6 +369,7 @@ _static_env_feature = feature(
                 ACTION_NAMES.cpp_compile,
                 ACTION_NAMES.cpp_header_parsing,
                 ACTION_NAMES.cpp_module_compile,
+                ACTION_NAMES.lto_backend,
             ],
             env_entries = [
                 env_entry(

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

@@ -413,6 +413,17 @@ private void validateDwp(
         .containsExactlyElementsIn(expectedInputs);
   }
 
+  @Test
+  public void testLtoBackendEnv() throws Exception {
+    createBuildFiles("features = ['env_feature'],");
+    setupThinLTOCrosstool(MockCcSupport.ENV_VAR_FEATURES);
+
+    LtoBackendAction backendAction =
+        getBackendAction("pkg/bin.lto/" + getRootExecPath() + "/pkg/_objs/bin/binfile.o");
+    assertThat(backendAction.getMnemonic()).isEqualTo("CcLtoBackendCompile");
+    assertThat(backendAction.getIncompleteEnvironmentForTesting()).containsEntry("cat", "meow");
+  }
+
   @Test
   public void testFission() throws Exception {
     createBuildFiles();
@@ -1074,10 +1085,10 @@ public void testAutoFdo() throws Exception {
                 linkAction, "pkg/bin.lto/" + rootExecPath + "/pkg/_objs/bin/binfile.o");
 
     // Checks that -fauto-profile is added to the LtoBackendAction.
-    assertThat(Joiner.on(" ").join(backendAction.getArguments())).containsMatch(
-        "-fauto-profile=[^ ]*/profile.afdo");
-    assertThat(ActionsTestUtil.baseArtifactNames(backendAction.getInputs())).contains(
-        "profile.afdo");
+    assertThat(Joiner.on(" ").join(backendAction.getArguments()))
+        .containsMatch("-fauto-profile=[^ ]*/profile.afdo");
+    assertThat(ActionsTestUtil.baseArtifactNames(backendAction.getInputs()))
+        .contains("profile.afdo");
   }
 
   private void setupThinLTOCrosstool(String... extraFeatures) throws Exception {