[memprof] Add InstrProfWriter::addMemProfData (#116528)

This patch adds InstrProfWriter::addMemProfData, which adds the
complete MemProf profile (frames, call stacks, and records) to the
writer context.

Without this function, functions like loadInput in llvm-profdata.cpp
and InstrProfWriter::mergeRecordsFromWriter must add one item (frame,
call stack, or record) at a time.  The new function std::moves the
entire MemProf profile to the writer context if the destination is
empty, which is the common use case.  Otherwise, we fall back to
adding one item at a time behind the scene.

Here are a couple of reasons why we should add this function:

- We've had a bug where we forgot to add one of the three data
  structures (frames, call stacks, and records) to the writer context,
  resulting in a nearly empty indexed profile.  We should always
  package the three data structures together, especially on API
  boundaries.

- We expose a little too much of the MemProf detail to
  InstrProfWriter.  I'd like to gradually transform
  InstrProfReader/Writer to entities managing buffers (sequences of
  bytes), with actual serialization/deserialization left to external
  classes.  We already do some of this in InstrProfReader, where
  InstrProfReader "contracts out" to IndexedMemProfReader to handle
  MemProf details.

I am not changing loadInput or InstrProfWriter::mergeRecordsFromWriter
for now because MemProfReader uses DenseMap for frames and call
stacks, whereas MemProfData uses MapVector.  I'll resolve these
mismatches in subsequent patches.

1 files changed, 29 insertions, 0 deletions

diff --git a/llvm/lib/ProfileData/InstrProfWriter.cpp b/llvm/lib/ProfileData/InstrProfWriter.cpp
index 47f4635..87a538f 100644
--- a/llvm/lib/ProfileData/InstrProfWriter.cpp
+++ b/llvm/lib/ProfileData/InstrProfWriter.cpp
@@ -350,6 +350,35 @@ bool InstrProfWriter::addMemProfCallStack(
   return true;
 }
 
+bool InstrProfWriter::addMemProfData(memprof::IndexedMemProfData Incoming,
+                                     function_ref<void(Error)> Warn) {
+  // TODO: Once we remove support for MemProf format Version V1, assert that
+  // the three components (frames, call stacks, and records) are either all
+  // empty or populated.
+
+  if (MemProfData.Frames.empty())
+    MemProfData.Frames = std::move(Incoming.Frames);
+  else
+    for (const auto &[Id, F] : Incoming.Frames)
+      if (addMemProfFrame(Id, F, Warn))
+        return false;
+
+  if (MemProfData.CallStacks.empty())
+    MemProfData.CallStacks = std::move(Incoming.CallStacks);
+  else
+    for (const auto &[CSId, CS] : Incoming.CallStacks)
+      if (addMemProfCallStack(CSId, CS, Warn))
+        return false;
+
+  if (MemProfData.Records.empty())
+    MemProfData.Records = std::move(Incoming.Records);
+  else
+    for (const auto &[GUID, Record] : Incoming.Records)
+      addMemProfRecord(GUID, Record);
+
+  return true;
+}
+
 void InstrProfWriter::addBinaryIds(ArrayRef<llvm::object::BuildID> BIs) {
   llvm::append_range(BinaryIds, BIs);
 }