[MemProf] Support for random hotness when writing profile (#113998)

Add support for generating random hotness in the memprof profile writer,
to be used for testing. The random seed is printed to stderr, and an
additional option enables providing a specific seed in order to
reproduce a particular random profile.

1 files changed, 11 insertions, 1 deletions

diff --git a/llvm/tools/llvm-profdata/llvm-profdata.cpp b/llvm/tools/llvm-profdata/llvm-profdata.cpp
index 59f0f1f..f7023aa 100644
--- a/llvm/tools/llvm-profdata/llvm-profdata.cpp
+++ b/llvm/tools/llvm-profdata/llvm-profdata.cpp
@@ -342,6 +342,15 @@ cl::opt<bool> MemProfFullSchema(
     "memprof-full-schema", cl::Hidden, cl::sub(MergeSubcommand),
     cl::desc("Use the full schema for serialization"), cl::init(false));
 
+static cl::opt<bool>
+    MemprofGenerateRandomHotness("memprof-random-hotness", cl::init(false),
+                                 cl::Hidden, cl::sub(MergeSubcommand),
+                                 cl::desc("Generate random hotness values"));
+static cl::opt<unsigned> MemprofGenerateRandomHotnessSeed(
+    "memprof-random-hotness-seed", cl::init(0), cl::Hidden,
+    cl::sub(MergeSubcommand),
+    cl::desc("Random hotness seed to use (0 to generate new seed)"));
+
 // Options specific to overlap subcommand.
 cl::opt<std::string> BaseFilename(cl::Positional, cl::Required,
                                   cl::desc("<base profile file>"),
@@ -641,7 +650,8 @@ struct WriterContext {
                 SmallSet<instrprof_error, 4> &WriterErrorCodes,
                 uint64_t ReservoirSize = 0, uint64_t MaxTraceLength = 0)
       : Writer(IsSparse, ReservoirSize, MaxTraceLength, DoWritePrevVersion,
-               MemProfVersionRequested, MemProfFullSchema),
+               MemProfVersionRequested, MemProfFullSchema,
+               MemprofGenerateRandomHotness, MemprofGenerateRandomHotnessSeed),
         ErrLock(ErrLock), WriterErrorCodes(WriterErrorCodes) {}
 };