[memprof] Add MemProf version (#86414)

This patch adds a version field to the MemProf section of the indexed
profile format, calling the new version "version 1".  The existing
version is called "version 0".

The writer supports both versions via a command-line option:

  llvm-profdata merge --memprof-version=1 ...

The reader supports both versions by automatically detecting the
version from the header.

1 files changed, 9 insertions, 1 deletions

diff --git a/llvm/tools/llvm-profdata/llvm-profdata.cpp b/llvm/tools/llvm-profdata/llvm-profdata.cpp
index 3a7bd06..e8ee3c2 100644
--- a/llvm/tools/llvm-profdata/llvm-profdata.cpp
+++ b/llvm/tools/llvm-profdata/llvm-profdata.cpp
@@ -300,6 +300,13 @@ cl::opt<bool> DoWritePrevVersion(
     cl::desc("Write the previous version of indexed format, to enable "
              "some forward compatibility."));
 
+cl::opt<memprof::IndexedVersion> MemProfVersionRequested(
+    "memprof-version", cl::Hidden, cl::sub(MergeSubcommand),
+    cl::desc("Specify the version of the memprof format to use"),
+    cl::init(memprof::Version0),
+    cl::values(clEnumValN(memprof::Version0, "0", "version 0"),
+               clEnumValN(memprof::Version1, "1", "version 1")));
+
 // Options specific to overlap subcommand.
 cl::opt<std::string> BaseFilename(cl::Positional, cl::Required,
                                   cl::desc("<base profile file>"),
@@ -588,7 +595,8 @@ struct WriterContext {
   WriterContext(bool IsSparse, std::mutex &ErrLock,
                 SmallSet<instrprof_error, 4> &WriterErrorCodes,
                 uint64_t ReservoirSize = 0, uint64_t MaxTraceLength = 0)
-      : Writer(IsSparse, ReservoirSize, MaxTraceLength, DoWritePrevVersion),
+      : Writer(IsSparse, ReservoirSize, MaxTraceLength, DoWritePrevVersion,
+               MemProfVersionRequested),
         ErrLock(ErrLock), WriterErrorCodes(WriterErrorCodes) {}
 };