--

MOS_MIGRATED_REVID=128827694

3 files changed, 8 insertions, 11 deletions

diff --git a/site/docs/bazel-user-manual.html b/site/docs/bazel-user-manual.html
index efdf1d1426..794497490c 100644
--- a/site/docs/bazel-user-manual.html
+++ b/site/docs/bazel-user-manual.html
@@ -1291,9 +1291,9 @@ $ bazel fetch //...
 
 </p>
 <p>
-  For the LLVM compiler the argument instead is the path to the raw LLVM profile
-  output file to generate, e.g.
-  <code class='flag'>--fdo_instrument=<var>/path/to/profile.profraw</var></code>.
+  For the LLVM compiler the argument is also the directory under which the raw LLVM profile
+  data file(s) is dumped, e.g.
+  <code class='flag'>--fdo_instrument=<var>/path/to/rawprof/dir/</var></code>.
 </p>
 <p>
   The options <code class='flag'>--fdo_instrument</code> and <code class='flag'>--fdo_optimize</code>
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 9943a79f47..03212b9fc2 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
@@ -873,10 +873,7 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
                 + "    action: 'c++-link-dynamic-library'"
                 + "    action: 'c++-link-executable'"
                 + "    flag_group {"
-                + "      flag: '-Xgcc-only=-fprofile-generate=%{fdo_instrument_path}'"
-                + "      flag: '-Xclang-only=-fprofile-instr-generate=%{fdo_instrument_path}'"
-                + "    }"
-                + "    flag_group {"
+                + "      flag: '-fprofile-generate=%{fdo_instrument_path}'"
                 + "      flag: '-fno-data-sections'"
                 + "    }"
                 + "  }"
@@ -894,8 +891,7 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
                 + "    action: 'c++-compile'"
                 + "    expand_if_all_available: 'fdo_profile_path'"
                 + "    flag_group {"
-                + "      flag: '-Xgcc-only=-fprofile-use=%{fdo_profile_path}'"
-                + "      flag: '-Xclang-only=-fprofile-instr-use=%{fdo_profile_path}'"
+                + "      flag: '-fprofile-use=%{fdo_profile_path}'"
                 + "      flag: '-Xclang-only=-Wno-profile-instr-unprofiled'"
                 + "      flag: '-Xclang-only=-Wno-profile-instr-out-of-date'"
                 + "      flag: '-fprofile-correction'"
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
index 0d60a44401..2195e3ff2d 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
@@ -379,8 +379,9 @@ public class CppOptions extends FragmentOptions {
     implicitRequirements = {"--copt=-Wno-error"},
     help =
         "Generate binaries with FDO instrumentation. Specify the relative "
-            + "directory name for the .gcda files at runtime. It also accepts "
-            + "an LLVM profile output file path."
+            + "directory name for the .gcda files at runtime with GCC compiler. "
+            + "With Clang/LLVM compiler, it also accepts the directory name under"
+            + "which the raw profile file(s) will be dumped at runtime."
   )
   public PathFragment fdoInstrument;