Convert LLVM raw profiles to indexed format if necessary.

Here is what is done today:

bazel build -c opt --fdo_optimize=<path_to_profdata_file> //target

The .profdata file is the LLVM profiles in indexed format and bazel creates a
symlink to it from bazel-fdo/_fdo/...  and compiles the target.

However, the instrumented binary generates a .profraw file and hence the
conversion to .profdata must be done manually using the llvm-profdata binary
which is shipped along with the crosstool as:
$ llvm-profdata -merge -o <path_to_profdata_file> <path_profraw_file>

We are trying to avoid this intermediate step in this change by baking this
into bazel.

This implementation does the following:

* In CppConfiguration.java, adds  new tool llvm-profdata.
* In CcToolchain.java, in function create, if LLVM instrumented FDO is desired,
  the profile format is checked and the profile conversion takes place.
* FdoSupport.java checks for LLVM instrumented FDO is bypassed.

RELNOTES[NEW]: Raw LLVM profiles are now supported.

PiperOrigin-RevId: 154569896

1 files changed, 1 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppFileTypes.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppFileTypes.java
index 597ebed521..cdda812667 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppFileTypes.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppFileTypes.java
@@ -156,6 +156,7 @@ public final class CppFileTypes {
   public static final FileType COVERAGE_DATA_IMPORTS = FileType.of(".gcda.imports");
   public static final FileType GCC_AUTO_PROFILE = FileType.of(".afdo");
   public static final FileType LLVM_PROFILE = FileType.of(".profdata");
+  public static final FileType LLVM_PROFILE_RAW = FileType.of(".profraw");
 
   public static final FileType CPP_MODULE_MAP = FileType.of(".cppmap");
   public static final FileType CPP_MODULE = FileType.of(".pcm");