1 files changed, 34 insertions, 23 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java
index 0e2f15463d..ad34044e68 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java
@@ -537,14 +537,23 @@ public class CppLinkActionBuilder {
     CppLinkVariablesExtension variablesExtension =
         isLTOIndexing
             ? new CppLinkVariablesExtension(
-                linkstampMap, needWholeArchive, linkerInputs, runtimeLinkerInputs, null, null)
+                configuration,
+                linkstampMap,
+                needWholeArchive,
+                linkerInputs,
+                runtimeLinkerInputs,
+                null,
+                linkerParamsFile,
+                ltoOutputRootPrefix)
             : new CppLinkVariablesExtension(
+                configuration,
                 linkstampMap,
                 needWholeArchive,
                 linkerInputs,
                 runtimeLinkerInputs,
                 output,
-                linkerParamsFile);
+                linkerParamsFile,
+                PathFragment.EMPTY_FRAGMENT);
     variablesExtension.addVariables(buildVariablesBuilder);
     for (VariablesExtension extraVariablesExtension : variablesExtensions) {
       extraVariablesExtension.addVariables(buildVariablesBuilder);
@@ -612,26 +621,8 @@ public class CppLinkActionBuilder {
           .setLinkopts(ImmutableList.copyOf(linkopts))
           .addLinkstampCompileOptions(linkstampOptions);
     } else {
-      // TODO(bazel-team): once the LLVM compiler patches have been finalized, this should
-      // be converted to a crosstool feature configuration instead.
       List<String> opts = new ArrayList<>(linkopts);
-      opts.add("-flto=thin");
-      if (linkerParamsFile != null) {
-        opts.add("-Wl,-plugin-opt,thinlto-index-only=" + linkerParamsFile.getExecPathString());
-      } else {
-        opts.add("-Wl,-plugin-opt,thinlto-index-only");
-      }
-      opts.add("-Wl,-plugin-opt,thinlto-emit-imports-files");
-      opts.add(
-          "-Wl,-plugin-opt,thinlto-prefix-replace="
-              + configuration.getBinDirectory(ruleContext.getRule().getRepository())
-                  .getExecPathString()
-              + ";"
-              + configuration
-                  .getBinDirectory(ruleContext.getRule().getRepository())
-                  .getExecPath()
-                  .getRelative(ltoOutputRootPrefix)
-                  .toString());
+      opts.addAll(featureConfiguration.getCommandLine("lto-indexing", buildVariables));
       linkCommandLineBuilder.setLinkopts(ImmutableList.copyOf(opts));
     }
 
@@ -1183,28 +1174,34 @@ public class CppLinkActionBuilder {
 
   private class CppLinkVariablesExtension implements VariablesExtension {
 
+    private final BuildConfiguration configuration;
     private final ImmutableMap<Artifact, Artifact> linkstampMap;
     private final boolean needWholeArchive;
     private final Iterable<LinkerInput> linkerInputs;
     private final ImmutableList<LinkerInput> runtimeLinkerInputs;
     private final Artifact outputArtifact;
     private final Artifact linkerParamsFile;
+    private final PathFragment ltoOutputRootPrefix;
 
     private final LinkArgCollector linkArgCollector = new LinkArgCollector();
 
     public CppLinkVariablesExtension(
+        BuildConfiguration configuration,
         ImmutableMap<Artifact, Artifact> linkstampMap,
         boolean needWholeArchive,
         Iterable<LinkerInput> linkerInputs,
         ImmutableList<LinkerInput> runtimeLinkerInputs,
         Artifact output,
-        Artifact linkerParamsFile) {
+        Artifact linkerParamsFile,
+        PathFragment ltoOutputRootPrefix) {
+      this.configuration = configuration;
       this.linkstampMap = linkstampMap;
       this.needWholeArchive = needWholeArchive;
       this.linkerInputs = linkerInputs;
       this.runtimeLinkerInputs = runtimeLinkerInputs;
       this.outputArtifact = output;
       this.linkerParamsFile = linkerParamsFile;
+      this.ltoOutputRootPrefix = ltoOutputRootPrefix;
 
       addInputFileLinkOptions(linkArgCollector);
     }
@@ -1274,6 +1271,20 @@ public class CppLinkActionBuilder {
             OUTPUT_EXECPATH_VARIABLE, this.outputArtifact.getExecPathString());
       }
 
+      if (!ltoOutputRootPrefix.equals(PathFragment.EMPTY_FRAGMENT)) {
+        if (linkerParamsFile != null) {
+          buildVariables.addVariable(
+              "thinlto_optional_params_file", "=" + linkerParamsFile.getExecPathString());
+        } else {
+          buildVariables.addVariable("thinlto_optional_params_file", "");
+        }
+        buildVariables.addVariable(
+            "thinlto_prefix_replace",
+            configuration.getBinDirectory().getExecPathString()
+                + ";"
+                + configuration.getBinDirectory().getExecPath().getRelative(ltoOutputRootPrefix));
+      }
+
       // Variables arising from the toolchain
       buildVariables
           .addAllVariables(CppHelper.getToolchain(ruleContext).getBuildVariables())
@@ -1450,7 +1461,7 @@ public class CppLinkActionBuilder {
               ltoMap);
         }
       }
-      if (linkerParamsFile != null) {
+      if (linkerParamsFile != null && ltoOutputRootPrefix.equals(PathFragment.EMPTY_FRAGMENT)) {
         standardArchiveInputParams.add("-Wl,@" + linkerParamsFile.getExecPathString());
       }