Collect .o files compiled from C(++), and skip the rest for the LTO backend step.

This should make ThinLTO work with .o files that are not generated by
compiling C++ in a cc_library()

--
MOS_MIGRATED_REVID=104764111

1 files changed, 24 insertions, 4 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkerInputs.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkerInputs.java
index e3875be2c1..21e4146c63 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkerInputs.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkerInputs.java
@@ -16,6 +16,7 @@ package com.google.devtools.build.lib.rules.cpp;
 
 import com.google.common.base.Function;
 import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.collect.CollectionUtils;
@@ -113,6 +114,8 @@ public abstract class LinkerInputs {
      * Returns whether the library is a solib symlink.
      */
     boolean isSolibSymlink();
+
+    Iterable<Artifact> getLTOBitcodeFiles();
   }
 
   /**
@@ -146,6 +149,11 @@ public abstract class LinkerInputs {
     }
 
     @Override
+    public Iterable<Artifact> getLTOBitcodeFiles() {
+      return ImmutableList.<Artifact>of();
+    }
+
+    @Override
     public boolean isFake() {
       return false;
     }
@@ -195,10 +203,16 @@ public abstract class LinkerInputs {
   private static class CompoundLibraryToLink implements LibraryToLink {
     private final Artifact libraryArtifact;
     private final Iterable<Artifact> objectFiles;
+    private final Iterable<Artifact> ltoBitcodeFiles;
 
-    private CompoundLibraryToLink(Artifact libraryArtifact, Iterable<Artifact> objectFiles) {
+    private CompoundLibraryToLink(
+        Artifact libraryArtifact,
+        Iterable<Artifact> objectFiles,
+        Iterable<Artifact> ltoBitcodeFiles) {
       this.libraryArtifact = Preconditions.checkNotNull(libraryArtifact);
       this.objectFiles = objectFiles == null ? null : CollectionUtils.makeImmutable(objectFiles);
+      this.ltoBitcodeFiles =
+          (ltoBitcodeFiles == null) ? null : CollectionUtils.makeImmutable(ltoBitcodeFiles);
     }
 
     @Override
@@ -233,6 +247,11 @@ public abstract class LinkerInputs {
     }
 
     @Override
+    public Iterable<Artifact> getLTOBitcodeFiles() {
+      return ltoBitcodeFiles;
+    }
+
+    @Override
     public boolean equals(Object that) {
       if (this == that) {
         return true;
@@ -318,14 +337,15 @@ public abstract class LinkerInputs {
     // Preconditions.checkArgument(
     //     !(artifact.getGeneratingAction() instanceof CppLinkAction) ||
     //     !Link.ARCHIVE_LIBRARY_FILETYPES.contains(artifact.getFileType()));
-    return new CompoundLibraryToLink(artifact, null);
+    return new CompoundLibraryToLink(artifact, null, null);
   }
 
   /**
    * Creates a library to link with the specified object files.
    */
-  public static LibraryToLink newInputLibrary(Artifact library, Iterable<Artifact> objectFiles) {
-    return new CompoundLibraryToLink(library, objectFiles);
+  public static LibraryToLink newInputLibrary(
+      Artifact library, Iterable<Artifact> objectFiles, Iterable<Artifact> ltoBitcodeFiles) {
+    return new CompoundLibraryToLink(library, objectFiles, ltoBitcodeFiles);
   }
 
   private static final Function<LibraryToLink, Artifact> LIBRARY_TO_NON_SOLIB =