Description redacted.

--
PiperOrigin-RevId: 145091484
MOS_MIGRATED_REVID=145091484

7 files changed, 128 insertions, 32 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcBinary.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcBinary.java
index b21536e797..6d8f41ce88 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcBinary.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcBinary.java
@@ -275,15 +275,21 @@ public abstract class CcBinary implements RuleConfiguredTargetFactory {
     // Store immutable context for use in other *_binary rules that are implemented by
     // linking the interpreter (Java, Python, etc.) together with native deps.
     CppLinkAction.Context linkContext = new CppLinkAction.Context(linkActionBuilder);
+    Iterable<LTOBackendArtifacts> ltoBackendArtifacts = ImmutableList.of();
+    boolean usePic = CppHelper.usePic(ruleContext, !isLinkShared(ruleContext));
 
     if (featureConfiguration.isEnabled(CppRuleClasses.THIN_LTO)) {
       linkActionBuilder.setLTOIndexing(true);
       CppLinkAction indexAction = linkActionBuilder.build();
       ruleContext.registerAction(indexAction);
 
-      for (LTOBackendArtifacts ltoArtifacts : indexAction.getAllLTOBackendArtifacts()) {
-        boolean usePic = CppHelper.usePic(ruleContext, !isLinkShared(ruleContext));
-        ltoArtifacts.scheduleLTOBackendAction(ruleContext, featureConfiguration, usePic);
+      ltoBackendArtifacts = indexAction.getAllLTOBackendArtifacts();
+      for (LTOBackendArtifacts ltoArtifacts : ltoBackendArtifacts) {
+        ltoArtifacts.scheduleLTOBackendAction(
+            ruleContext,
+            featureConfiguration,
+            usePic,
+            /*generateDwo=*/ cppConfiguration.useFission());
       }
 
       linkActionBuilder.setLTOIndexing(false);
@@ -317,7 +323,13 @@ public abstract class CcBinary implements RuleConfiguredTargetFactory {
     CppHelper.createStripAction(ruleContext, cppConfiguration, executable, strippedFile);
 
     DwoArtifactsCollector dwoArtifacts =
-        collectTransitiveDwoArtifacts(ruleContext, ccCompilationOutputs, linkStaticness);
+        collectTransitiveDwoArtifacts(
+            ruleContext,
+            ccCompilationOutputs,
+            linkStaticness,
+            cppConfiguration.useFission(),
+            usePic,
+            ltoBackendArtifacts);
     Artifact dwpFile =
         ruleContext.getImplicitOutputArtifact(CppRuleClasses.CC_BINARY_DEBUG_PACKAGE);
     createDebugPackagerActions(ruleContext, cppConfiguration, dwpFile, dwoArtifacts);
@@ -514,16 +526,23 @@ public abstract class CcBinary implements RuleConfiguredTargetFactory {
    * Collects .dwo artifacts either transitively or directly, depending on the link type.
    *
    * <p>For a cc_binary, we only include the .dwo files corresponding to the .o files that are
-   * passed into the link. For static linking, this includes all transitive dependencies. But
-   * for dynamic linking, dependencies are separately linked into their own shared libraries,
-   * so we don't need them here.
+   * passed into the link. For static linking, this includes all transitive dependencies. But for
+   * dynamic linking, dependencies are separately linked into their own shared libraries, so we
+   * don't need them here.
    */
-  private static DwoArtifactsCollector collectTransitiveDwoArtifacts(RuleContext context,
-      CcCompilationOutputs compilationOutputs, LinkStaticness linkStaticness) {
+  private static DwoArtifactsCollector collectTransitiveDwoArtifacts(
+      RuleContext context,
+      CcCompilationOutputs compilationOutputs,
+      LinkStaticness linkStaticness,
+      boolean generateDwo,
+      boolean ltoBackendArtifactsUsePic,
+      Iterable<LTOBackendArtifacts> ltoBackendArtifacts) {
     if (linkStaticness == LinkStaticness.DYNAMIC) {
-      return DwoArtifactsCollector.directCollector(compilationOutputs);
+      return DwoArtifactsCollector.directCollector(
+          context, compilationOutputs, generateDwo, ltoBackendArtifactsUsePic, ltoBackendArtifacts);
     } else {
-      return CcCommon.collectTransitiveDwoArtifacts(context, compilationOutputs);
+      return CcCommon.collectTransitiveDwoArtifacts(
+          context, compilationOutputs, generateDwo, ltoBackendArtifactsUsePic, ltoBackendArtifacts);
     }
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java
index c1128f773a..7cc659e1b5 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java
@@ -162,12 +162,13 @@ public final class CcCommon {
     return ruleContext.attributes().has(name, type);
   }
 
-  /**
-   * Collects all .dwo artifacts in this target's transitive closure.
-   */
+  /** Collects all .dwo artifacts in this target's transitive closure. */
   public static DwoArtifactsCollector collectTransitiveDwoArtifacts(
       RuleContext ruleContext,
-      CcCompilationOutputs compilationOutputs) {
+      CcCompilationOutputs compilationOutputs,
+      boolean generateDwo,
+      boolean ltoBackendArtifactsUsePic,
+      Iterable<LTOBackendArtifacts> ltoBackendArtifacts) {
     ImmutableList.Builder<TransitiveInfoCollection> deps =
         ImmutableList.<TransitiveInfoCollection>builder();
 
@@ -177,9 +178,15 @@ public final class CcCommon {
       deps.add(CppHelper.mallocForTarget(ruleContext));
     }
 
-    return compilationOutputs == null  // Possible in LIPO collection mode (see initializationHook).
+    return compilationOutputs == null // Possible in LIPO collection mode (see initializationHook).
         ? DwoArtifactsCollector.emptyCollector()
-        : DwoArtifactsCollector.transitiveCollector(compilationOutputs, deps.build());
+        : DwoArtifactsCollector.transitiveCollector(
+            ruleContext,
+            compilationOutputs,
+            deps.build(),
+            generateDwo,
+            ltoBackendArtifactsUsePic,
+            ltoBackendArtifacts);
   }
 
   public TransitiveLipoInfoProvider collectTransitiveLipoLabels(CcCompilationOutputs outputs) {
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 a172f805da..4a5692014d 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
@@ -926,7 +926,13 @@ public final class CcLibraryHelper {
     }
 
     DwoArtifactsCollector dwoArtifacts =
-        DwoArtifactsCollector.transitiveCollector(ccOutputs, deps);
+        DwoArtifactsCollector.transitiveCollector(
+            ruleContext,
+            ccOutputs,
+            deps, /*generateDwo=*/
+            false, /*ltoBackendArtifactsUsePic=*/
+            false, /*ltoBackendArtifacts=*/
+            ImmutableList.of());
     Runfiles cppStaticRunfiles = collectCppRunfiles(ccLinkingOutputs, true);
     Runfiles cppSharedRunfiles = collectCppRunfiles(ccLinkingOutputs, false);
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
index ec1ef1e3b8..64f1db9375 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
@@ -829,6 +829,7 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
                   + "    action: 'c++-compile'"
                   + "    action: 'assemble'"
                   + "    action: 'preprocess-assemble'"
+                  + "    action: 'lto-backend'"
                   + "    expand_if_all_available: 'per_object_debug_info_file'"
                   + "    flag_group {"
                   + "      flag: '-gsplit-dwarf'"
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 c3dee0b557..4c134a512d 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
@@ -508,6 +508,9 @@ public final class CppModel {
       } else if (CppFileTypes.CLIF_INPUT_PROTO.matches(source.getSource().getExecPath())) {
         createClifMatchAction(outputName, result, env, builder);
       } else {
+        boolean bitcodeOutput =
+            featureConfiguration.isEnabled(CppRuleClasses.THIN_LTO)
+                && CppFileTypes.LTO_SOURCE.matches(sourceArtifact.getFilename());
         createSourceAction(
             outputName,
             result,
@@ -517,7 +520,10 @@ public final class CppModel {
             ArtifactCategory.OBJECT_FILE,
             /*addObject=*/ true,
             isCodeCoverageEnabled(),
-            /*generateDwo=*/ cppConfiguration.useFission(),
+            // The source action does not generate dwo when it has bitcode
+            // output (since it isn't generating a native object with debug
+            // info). In that case the LTOBackendAction will generate the dwo.
+            /*generateDwo=*/ cppConfiguration.useFission() && !bitcodeOutput,
             CppFileTypes.mustProduceDotdFile(sourceArtifact.getFilename()),
             source.getBuildVariables());
       }
@@ -966,7 +972,15 @@ public final class CppModel {
 
       for (LTOBackendArtifacts ltoArtifacts : indexAction.getAllLTOBackendArtifacts()) {
         ltoArtifacts.scheduleLTOBackendAction(
-            ruleContext, featureConfiguration, usePicForSharedLibs);
+            ruleContext,
+            featureConfiguration,
+            usePicForSharedLibs,
+            // If support is ever added for generating a dwp file for shared
+            // library targets (e.g. when linkstatic=0), then this should change
+            // to generate dwo files when cppConfiguration.useFission(),
+            // and the dwp generating action for the shared library should
+            // include all of the resulting dwo files.
+            /*generateDwo=*/ false);
       }
 
       linkActionBuilder.setLTOIndexing(false);
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/DwoArtifactsCollector.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/DwoArtifactsCollector.java
index c097198c7f..5745d35d0c 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/DwoArtifactsCollector.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/DwoArtifactsCollector.java
@@ -15,6 +15,7 @@ package com.google.devtools.build.lib.rules.cpp;
 
 import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
@@ -38,11 +39,14 @@ public class DwoArtifactsCollector {
    */
   private final NestedSet<Artifact> picDwoArtifacts;
 
-  /**
-   * Instantiates a "real" collector on meaningful data.
-   */
-  private DwoArtifactsCollector(CcCompilationOutputs compilationOutputs,
-        Iterable<TransitiveInfoCollection> deps) {
+  /** Instantiates a "real" collector on meaningful data. */
+  private DwoArtifactsCollector(
+      RuleContext ruleContext,
+      CcCompilationOutputs compilationOutputs,
+      Iterable<TransitiveInfoCollection> deps,
+      boolean generateDwo,
+      boolean ltoBackendArtifactsUsePic,
+      Iterable<LTOBackendArtifacts> ltoBackendArtifacts) {
 
     Preconditions.checkNotNull(compilationOutputs);
     Preconditions.checkNotNull(deps);
@@ -56,6 +60,19 @@ public class DwoArtifactsCollector {
     dwoBuilder.addAll(compilationOutputs.getDwoFiles());
     picDwoBuilder.addAll(compilationOutputs.getPicDwoFiles());
 
+    // If we are generating .dwo, add any generated for LTOBackendArtifacts.
+    if (generateDwo) {
+      for (LTOBackendArtifacts ltoBackendArtifact : ltoBackendArtifacts) {
+        Artifact objectFile = ltoBackendArtifact.getObjectFile();
+        if (ltoBackendArtifactsUsePic) {
+          picDwoBuilder.add(
+              ruleContext.getRelatedArtifact(objectFile.getRootRelativePath(), ".dwo"));
+        } else {
+          dwoBuilder.add(ruleContext.getRelatedArtifact(objectFile.getRootRelativePath(), ".dwo"));
+        }
+      }
+    }
+
     for (TransitiveInfoCollection info : deps) {
       CppDebugFileProvider provider = info.getProvider(CppDebugFileProvider.class);
       if (provider != null) {
@@ -82,9 +99,20 @@ public class DwoArtifactsCollector {
    * @param compilationOutputs the output compilation context for the owning target
    * @param deps which of the target's transitive info collections should be visited
    */
-  public static DwoArtifactsCollector transitiveCollector(CcCompilationOutputs compilationOutputs,
-      Iterable<TransitiveInfoCollection> deps) {
-    return new DwoArtifactsCollector(compilationOutputs, deps);
+  public static DwoArtifactsCollector transitiveCollector(
+      RuleContext ruleContext,
+      CcCompilationOutputs compilationOutputs,
+      Iterable<TransitiveInfoCollection> deps,
+      boolean generateDwo,
+      boolean ltoBackendArtifactsUsePic,
+      Iterable<LTOBackendArtifacts> ltoBackendArtifacts) {
+    return new DwoArtifactsCollector(
+        ruleContext,
+        compilationOutputs,
+        deps,
+        generateDwo,
+        ltoBackendArtifactsUsePic,
+        ltoBackendArtifacts);
   }
 
   /**
@@ -92,9 +120,19 @@ public class DwoArtifactsCollector {
    *
    * @param compilationOutputs the output compilation context for the owning target
    */
-  public static DwoArtifactsCollector directCollector(CcCompilationOutputs compilationOutputs) {
-      return new DwoArtifactsCollector(
-          compilationOutputs, ImmutableList.<TransitiveInfoCollection>of());
+  public static DwoArtifactsCollector directCollector(
+      RuleContext ruleContext,
+      CcCompilationOutputs compilationOutputs,
+      boolean generateDwo,
+      boolean ltoBackendArtifactsUsePic,
+      Iterable<LTOBackendArtifacts> ltoBackendArtifacts) {
+    return new DwoArtifactsCollector(
+        ruleContext,
+        compilationOutputs,
+        ImmutableList.<TransitiveInfoCollection>of(),
+        generateDwo,
+        ltoBackendArtifactsUsePic,
+        ltoBackendArtifacts);
   }
 
   /**
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/LTOBackendArtifacts.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/LTOBackendArtifacts.java
index 1d2a25c9af..b509bf9007 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/LTOBackendArtifacts.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/LTOBackendArtifacts.java
@@ -106,7 +106,10 @@ public final class LTOBackendArtifacts {
   }
 
   public void scheduleLTOBackendAction(
-      RuleContext ruleContext, FeatureConfiguration featureConfiguration, boolean usePic) {
+      RuleContext ruleContext,
+      FeatureConfiguration featureConfiguration,
+      boolean usePic,
+      boolean generateDwo) {
     LTOBackendAction.Builder builder = new LTOBackendAction.Builder();
     builder.addImportsInfo(bitcodeFiles, imports);
 
@@ -139,6 +142,14 @@ public final class LTOBackendArtifacts {
     if (autoFdoProfile != null) {
       builder.addInput(autoFdoProfile);
     }
+
+    if (generateDwo) {
+      Artifact dwoFile = ruleContext.getRelatedArtifact(objectFile.getRootRelativePath(), ".dwo");
+      builder.addOutput(dwoFile);
+      buildVariablesBuilder.addStringVariable(
+          "per_object_debug_info_file", dwoFile.getExecPathString());
+    }
+
     Variables buildVariables = buildVariablesBuilder.build();
     List<String> execArgs = new ArrayList<>();
     execArgs.addAll(featureConfiguration.getCommandLine("lto-backend", buildVariables));