[llvm] [ctx_profile] Profile reader and writer (PR #91859)

[Snehasish Kumar via llvm-commits]

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@@ -0,0 +1,164 @@
+//===- PGOCtxProfReader.cpp - Contextual Instrumentation profile reader ---===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Read a contextual profile into a datastructure suitable for maintenance
+// throughout IPO
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ProfileData/PGOCtxProfReader.h"
+#include "llvm/Bitstream/BitCodeEnums.h"
+#include "llvm/Bitstream/BitstreamReader.h"
+#include "llvm/ProfileData/PGOCtxProfWriter.h"
+#include "llvm/Support/Errc.h"
+#include "llvm/Support/Error.h"
+
+using namespace llvm;
+
+#define EXPECT_OR_RET(LHS, RHS)                                                \
+  auto LHS = RHS;                                                              \
+  if (!LHS)                                                                    \
+    return LHS.takeError();
+
+#define RET_ON_ERR(EXPR)                                                       \
+  if (auto Err = (EXPR))                                                       \
+    return Err;
+
+Expected<PGOContextualProfile &>
+PGOContextualProfile::getOrEmplace(uint32_t Index, GlobalValue::GUID G,
+                                   SmallVectorImpl<uint64_t> &&Counters) {
+  auto I = Callsites[Index].insert(
+      {G, PGOContextualProfile(G, std::move(Counters))});
+  if (!I.second)
+    return make_error<StringError>(llvm::errc::invalid_argument,
+                                   "Duplicate GUID for same callsite.");
+  return I.first->second;
+}
+
+void PGOContextualProfile::getContainedGuids(
+    DenseSet<GlobalValue::GUID> &Guids) const {
+  Guids.insert(GUID);
+  for (const auto &[_, Callsite] : Callsites)
+    for (const auto &[_, Callee] : Callsite)
+      Callee.getContainedGuids(Guids);
+}
+
+Expected<BitstreamEntry> PGOCtxProfileReader::advance() {
+  return Cursor.advance(BitstreamCursor::AF_DontAutoprocessAbbrevs);
+}
+
+Error PGOCtxProfileReader::wrongValue(const Twine &Msg) {
+  return make_error<StringError>(llvm::errc::invalid_argument, Msg);
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snehasish wrote:

Can you use InstrProfError instead of StringError here?

https://github.com/llvm/llvm-project/pull/91859