Rollforward of []: Blaze changes to support LLVM profile feedback

Rollback of commit b961bb931400044ed91e6b0b596f94fe983f9f17.

--
MOS_MIGRATED_REVID=98833728

1 files changed, 39 insertions, 5 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupport.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupport.java
index 592fe2c295..a2339c2b2a 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupport.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupport.java
@@ -121,13 +121,20 @@ public class FdoSupport {
   private static final PathFragment ZIP_ROOT = new PathFragment("/");
 
   /**
-   * Returns true if the give fdoFile represents an AutoFdo profile.
+   * Returns true if the given fdoFile represents an AutoFdo profile.
    */
   public static final boolean isAutoFdo(String fdoFile) {
     return CppFileTypes.GCC_AUTO_PROFILE.matches(fdoFile);
   }
 
   /**
+   * Returns true if the given fdoFile represents an LLVM profile.
+   */
+  public static final boolean isLLVMFdo(String fdoFile) {
+    return CppFileTypes.LLVM_PROFILE.matches(fdoFile);
+  }
+
+  /**
    * Coverage information output directory passed to {@code --fdo_instrument},
    * or {@code null} if FDO instrumentation is disabled.
    */
@@ -173,6 +180,12 @@ public class FdoSupport {
   private final boolean useAutoFdo;
 
   /**
+   * Flag indicating whether to use LLVM instrumentation-based FDO (as
+   * opposed to GCC instrumentation-based FDO).
+   */
+  private final boolean useLLVMFdo;
+
+  /**
    * The {@code .gcda} files that have been extracted from the ZIP file,
    * relative to the root of the ZIP file.
    *
@@ -217,6 +230,7 @@ public class FdoSupport {
             fdoProfile.getBaseName()));
     this.lipoMode = lipoMode;
     this.useAutoFdo = fdoProfile != null && isAutoFdo(fdoProfile.getBaseName());
+    this.useLLVMFdo = fdoProfile != null && isLLVMFdo(fdoProfile.getBaseName());
   }
 
   public Root getFdoRoot() {
@@ -276,6 +290,9 @@ public class FdoSupport {
         }
         FileSystemUtils.ensureSymbolicLink(
             execRoot.getRelative(getAutoProfilePath()), fdoProfile);
+      } else if (useLLVMFdo) {
+        FileSystemUtils.ensureSymbolicLink(
+            execRoot.getRelative(getLLVMProfilePath()), fdoProfile);
       } else {
         Path zipFilePath = new ZipFileSystem(fdoProfile).getRootDirectory();
         if (!zipFilePath.getRelative("blaze-out").isDirectory()) {
@@ -477,8 +494,13 @@ public class FdoSupport {
               getAutoProfilePath().getPathString());
         }
         if (featureConfiguration.isEnabled(CppRuleClasses.FDO_OPTIMIZE)) {
-          buildVariables.addVariable("fdo_profile_path",
-              fdoRootExecPath.getPathString());
+          if (useLLVMFdo) {
+            buildVariables.addVariable("fdo_profile_path",
+                getLLVMProfilePath().getPathString());
+          } else {
+            buildVariables.addVariable("fdo_profile_path",
+                fdoRootExecPath.getPathString());
+          }
         }
       } else {
         // TODO(bazel-team): Remove this workaround once the feature configuration
@@ -516,11 +538,14 @@ public class FdoSupport {
     // If --fdo_optimize was not specified, we don't have any additional inputs.
     if (fdoProfile == null) {
       return ImmutableSet.of();
-    } else if (useAutoFdo) {
+    } else if (useAutoFdo || useLLVMFdo) {
       ImmutableSet.Builder<Artifact> auxiliaryInputs = ImmutableSet.builder();
 
+      PathFragment profileRootRelativePath = (useLLVMFdo)
+          ? getLLVMProfileRootRelativePath()
+          : getAutoProfileRootRelativePath();
       Artifact artifact = env.getDerivedArtifact(
-          fdoPath.getRelative(getAutoProfileRootRelativePath()), fdoRoot);
+          fdoPath.getRelative(profileRootRelativePath), fdoRoot);
       env.registerAction(new FdoStubAction(ruleContext.getActionOwner(), artifact));
       auxiliaryInputs.add(artifact);
       if (lipoContextProvider != null) {
@@ -624,6 +649,15 @@ public class FdoSupport {
     return new PathFragment(fdoProfile.getBaseName());
   }
 
+
+  private PathFragment getLLVMProfilePath() {
+    return fdoRootExecPath.getRelative(getLLVMProfileRootRelativePath());
+  }
+
+  private PathFragment getLLVMProfileRootRelativePath() {
+    return new PathFragment(fdoProfile.getBaseName());
+  }
+
   /**
    * Returns whether LIPO is enabled.
    */