[clang] [APINotes] Upstream APINotesManager (PR #72389)

[Saleem Abdulrasool via cfe-commits]

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+//===--- APINotesManager.cpp - Manage API Notes Files ---------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/APINotes/APINotesManager.h"
+#include "clang/APINotes/APINotesReader.h"
+#include "clang/APINotes/APINotesYAMLCompiler.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Basic/LangOptions.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Basic/SourceMgrAdapter.h"
+#include "clang/Basic/Version.h"
+#include "llvm/ADT/APInt.h"
+#include "llvm/ADT/Hashing.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/PrettyStackTrace.h"
+
+using namespace clang;
+using namespace api_notes;
+
+#define DEBUG_TYPE "API Notes"
+STATISTIC(NumHeaderAPINotes, "non-framework API notes files loaded");
+STATISTIC(NumPublicFrameworkAPINotes, "framework public API notes loaded");
+STATISTIC(NumPrivateFrameworkAPINotes, "framework private API notes loaded");
+STATISTIC(NumFrameworksSearched, "frameworks searched");
+STATISTIC(NumDirectoriesSearched, "header directories searched");
+STATISTIC(NumDirectoryCacheHits, "directory cache hits");
+
+namespace {
+/// Prints two successive strings, which much be kept alive as long as the
+/// PrettyStackTrace entry.
+class PrettyStackTraceDoubleString : public llvm::PrettyStackTraceEntry {
+  StringRef First, Second;
+
+public:
+  PrettyStackTraceDoubleString(StringRef First, StringRef Second)
+      : First(First), Second(Second) {}
+  void print(raw_ostream &OS) const override { OS << First << Second; }
+};
+} // namespace
+
+APINotesManager::APINotesManager(SourceManager &SM, const LangOptions &LangOpts)
+    : SM(SM), ImplicitAPINotes(LangOpts.APINotes) {}
+
+APINotesManager::~APINotesManager() {
+  // Free the API notes readers.
+  for (const auto &Entry : Readers) {
+    if (auto Reader = Entry.second.dyn_cast<APINotesReader *>())
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compnerd wrote:

Why is the `dyn_cast` needed here?  The `Readers` is an array of `APINotesReader *`.  Should we instead consider using `std::unique_ptr<APINotesReader> Readers[2]` to avoid this and allow C++ to manage the memory properly?  Or are these readers allocated off a bump pointer allocator or something?

https://github.com/llvm/llvm-project/pull/72389