[APINotes] Upstream APINotesManager

This upstreams more of the Clang API Notes functionality that is
currently implemented in the Apple fork:
https://github.com/apple/llvm-project/tree/next/clang/lib/APINotes

2 files changed, 459 insertions, 0 deletions

diff --git a/clang/lib/APINotes/APINotesManager.cpp b/clang/lib/APINotes/APINotesManager.cpp
new file mode 100644
index 0000000..ec1fb3f
--- /dev/null
+++ b/clang/lib/APINotes/APINotesManager.cpp
@@ -0,0 +1,458 @@
+//===--- 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 *>())
+      delete Reader;
+  }
+
+  delete CurrentModuleReaders[ReaderKind::Public];
+  delete CurrentModuleReaders[ReaderKind::Private];
+}
+
+std::unique_ptr<APINotesReader>
+APINotesManager::loadAPINotes(FileEntryRef APINotesFile) {
+  PrettyStackTraceDoubleString Trace("Loading API notes from ",
+                                     APINotesFile.getName());
+
+  // Open the source file.
+  auto SourceFileID = SM.getOrCreateFileID(APINotesFile, SrcMgr::C_User);
+  auto SourceBuffer = SM.getBufferOrNone(SourceFileID, SourceLocation());
+  if (!SourceBuffer)
+    return nullptr;
+
+  // Compile the API notes source into a buffer.
+  // FIXME: Either propagate OSType through or, better yet, improve the binary
+  // APINotes format to maintain complete availability information.
+  // FIXME: We don't even really need to go through the binary format at all;
+  // we're just going to immediately deserialize it again.
+  llvm::SmallVector<char, 1024> APINotesBuffer;
+  std::unique_ptr<llvm::MemoryBuffer> CompiledBuffer;
+  {
+    SourceMgrAdapter SMAdapter(
+        SM, SM.getDiagnostics(), diag::err_apinotes_message,
+        diag::warn_apinotes_message, diag::note_apinotes_message, APINotesFile);
+    llvm::raw_svector_ostream OS(APINotesBuffer);
+    if (api_notes::compileAPINotes(
+            SourceBuffer->getBuffer(), SM.getFileEntryForID(SourceFileID), OS,
+            SMAdapter.getDiagHandler(), SMAdapter.getDiagContext()))
+      return nullptr;
+
+    // Make a copy of the compiled form into the buffer.
+    CompiledBuffer = llvm::MemoryBuffer::getMemBufferCopy(
+        StringRef(APINotesBuffer.data(), APINotesBuffer.size()));
+  }
+
+  // Load the binary form we just compiled.
+  auto Reader = APINotesReader::Create(std::move(CompiledBuffer), SwiftVersion);
+  assert(Reader && "Could not load the API notes we just generated?");
+  return Reader;
+}
+
+std::unique_ptr<APINotesReader>
+APINotesManager::loadAPINotes(StringRef Buffer) {
+  llvm::SmallVector<char, 1024> APINotesBuffer;
+  std::unique_ptr<llvm::MemoryBuffer> CompiledBuffer;
+  SourceMgrAdapter SMAdapter(
+      SM, SM.getDiagnostics(), diag::err_apinotes_message,
+      diag::warn_apinotes_message, diag::note_apinotes_message, std::nullopt);
+  llvm::raw_svector_ostream OS(APINotesBuffer);
+
+  if (api_notes::compileAPINotes(Buffer, nullptr, OS,
+                                 SMAdapter.getDiagHandler(),
+                                 SMAdapter.getDiagContext()))
+    return nullptr;
+
+  CompiledBuffer = llvm::MemoryBuffer::getMemBufferCopy(
+      StringRef(APINotesBuffer.data(), APINotesBuffer.size()));
+  auto Reader = APINotesReader::Create(std::move(CompiledBuffer), SwiftVersion);
+  assert(Reader && "Could not load the API notes we just generated?");
+  return Reader;
+}
+
+bool APINotesManager::loadAPINotes(const DirectoryEntry *HeaderDir,
+                                   FileEntryRef APINotesFile) {
+  assert(Readers.find(HeaderDir) == Readers.end());
+  if (auto Reader = loadAPINotes(APINotesFile)) {
+    Readers[HeaderDir] = Reader.release();
+    return false;
+  }
+
+  Readers[HeaderDir] = nullptr;
+  return true;
+}
+
+OptionalFileEntryRef
+APINotesManager::findAPINotesFile(DirectoryEntryRef Directory,
+                                  StringRef Basename, bool WantPublic) {
+  FileManager &FM = SM.getFileManager();
+
+  llvm::SmallString<128> Path(Directory.getName());
+
+  StringRef Suffix = WantPublic ? "" : "_private";
+
+  // Look for the source API notes file.
+  llvm::sys::path::append(Path, llvm::Twine(Basename) + Suffix + "." +
+                                    SOURCE_APINOTES_EXTENSION);
+  return FM.getOptionalFileRef(Path, /*Open*/ true);
+}
+
+OptionalDirectoryEntryRef APINotesManager::loadFrameworkAPINotes(
+    llvm::StringRef FrameworkPath, llvm::StringRef FrameworkName, bool Public) {
+  FileManager &FM = SM.getFileManager();
+
+  llvm::SmallString<128> Path(FrameworkPath);
+  unsigned FrameworkNameLength = Path.size();
+
+  StringRef Suffix = Public ? "" : "_private";
+
+  // Form the path to the APINotes file.
+  llvm::sys::path::append(Path, "APINotes");
+  llvm::sys::path::append(Path, (llvm::Twine(FrameworkName) + Suffix + "." +
+                                 SOURCE_APINOTES_EXTENSION));
+
+  // Try to open the APINotes file.
+  auto APINotesFile = FM.getOptionalFileRef(Path);
+  if (!APINotesFile)
+    return std::nullopt;
+
+  // Form the path to the corresponding header directory.
+  Path.resize(FrameworkNameLength);
+  llvm::sys::path::append(Path, Public ? "Headers" : "PrivateHeaders");
+
+  // Try to access the header directory.
+  auto HeaderDir = FM.getOptionalDirectoryRef(Path);
+  if (!HeaderDir)
+    return std::nullopt;
+
+  // Try to load the API notes.
+  if (loadAPINotes(*HeaderDir, *APINotesFile))
+    return std::nullopt;
+
+  // Success: return the header directory.
+  if (Public)
+    ++NumPublicFrameworkAPINotes;
+  else
+    ++NumPrivateFrameworkAPINotes;
+  return *HeaderDir;
+}
+
+static void checkPrivateAPINotesName(DiagnosticsEngine &Diags,
+                                     const FileEntry *File, const Module *M) {
+  if (File->tryGetRealPathName().empty())
+    return;
+
+  StringRef RealFileName =
+      llvm::sys::path::filename(File->tryGetRealPathName());
+  StringRef RealStem = llvm::sys::path::stem(RealFileName);
+  if (RealStem.endswith("_private"))
+    return;
+
+  unsigned DiagID = diag::warn_apinotes_private_case;
+  if (M->IsSystem)
+    DiagID = diag::warn_apinotes_private_case_system;
+
+  Diags.Report(SourceLocation(), DiagID) << M->Name << RealFileName;
+}
+
+/// \returns true if any of \p module's immediate submodules are defined in a
+/// private module map
+static bool hasPrivateSubmodules(const Module *M) {
+  return llvm::any_of(M->submodules(), [](const Module *Submodule) {
+    return Submodule->ModuleMapIsPrivate;
+  });
+}
+
+llvm::SmallVector<FileEntryRef, 2>
+APINotesManager::getCurrentModuleAPINotes(Module *M, bool LookInModule,
+                                          ArrayRef<std::string> SearchPaths) {
+  FileManager &FM = SM.getFileManager();
+  auto ModuleName = M->getTopLevelModuleName();
+  llvm::SmallVector<FileEntryRef, 2> APINotes;
+
+  // First, look relative to the module itself.
+  if (LookInModule) {
+    // Local function to try loading an API notes file in the given directory.
+    auto tryAPINotes = [&](DirectoryEntryRef Dir, bool WantPublic) {
+      if (auto File = findAPINotesFile(Dir, ModuleName, WantPublic)) {
+        if (!WantPublic)
+          checkPrivateAPINotesName(SM.getDiagnostics(), *File, M);
+
+        APINotes.push_back(*File);
+      }
+    };
+
+    if (M->IsFramework) {
+      // For frameworks, we search in the "Headers" or "PrivateHeaders"
+      // subdirectory.
+      //
+      // Public modules:
+      // - Headers/Foo.apinotes
+      // - PrivateHeaders/Foo_private.apinotes (if there are private submodules)
+      // Private modules:
+      // - PrivateHeaders/Bar.apinotes (except that 'Bar' probably already has
+      //   the word "Private" in it in practice)
+      llvm::SmallString<128> Path(M->Directory->getName());
+
+      if (!M->ModuleMapIsPrivate) {
+        unsigned PathLen = Path.size();
+
+        llvm::sys::path::append(Path, "Headers");
+        if (auto APINotesDir = FM.getOptionalDirectoryRef(Path))
+          tryAPINotes(*APINotesDir, /*wantPublic=*/true);
+
+        Path.resize(PathLen);
+      }
+
+      if (M->ModuleMapIsPrivate || hasPrivateSubmodules(M)) {
+        llvm::sys::path::append(Path, "PrivateHeaders");
+        if (auto PrivateAPINotesDir = FM.getOptionalDirectoryRef(Path))
+          tryAPINotes(*PrivateAPINotesDir,
+                      /*wantPublic=*/M->ModuleMapIsPrivate);
+      }
+    } else {
+      // Public modules:
+      // - Foo.apinotes
+      // - Foo_private.apinotes (if there are private submodules)
+      // Private modules:
+      // - Bar.apinotes (except that 'Bar' probably already has the word
+      //   "Private" in it in practice)
+      tryAPINotes(*M->Directory, /*wantPublic=*/true);
+      if (!M->ModuleMapIsPrivate && hasPrivateSubmodules(M))
+        tryAPINotes(*M->Directory, /*wantPublic=*/false);
+    }
+
+    if (!APINotes.empty())
+      return APINotes;
+  }
+
+  // Second, look for API notes for this module in the module API
+  // notes search paths.
+  for (const auto &SearchPath : SearchPaths) {
+    if (auto SearchDir = FM.getOptionalDirectoryRef(SearchPath)) {
+      if (auto File = findAPINotesFile(*SearchDir, ModuleName)) {
+        APINotes.push_back(*File);
+        return APINotes;
+      }
+    }
+  }
+
+  // Didn't find any API notes.
+  return APINotes;
+}
+
+bool APINotesManager::loadCurrentModuleAPINotes(
+    Module *M, bool LookInModule, ArrayRef<std::string> SearchPaths) {
+  assert(!CurrentModuleReaders[ReaderKind::Public] &&
+         "Already loaded API notes for the current module?");
+
+  auto APINotes = getCurrentModuleAPINotes(M, LookInModule, SearchPaths);
+  unsigned NumReaders = 0;
+  for (auto File : APINotes) {
+    CurrentModuleReaders[NumReaders++] = loadAPINotes(File).release();
+    if (!getCurrentModuleReaders().empty())
+      M->APINotesFile = File.getName().str();
+  }
+
+  return NumReaders > 0;
+}
+
+bool APINotesManager::loadCurrentModuleAPINotesFromBuffer(
+    ArrayRef<StringRef> Buffers) {
+  unsigned NumReader = 0;
+  for (auto Buf : Buffers) {
+    auto Reader = loadAPINotes(Buf);
+    assert(Reader && "Could not load the API notes we just generated?");
+
+    CurrentModuleReaders[NumReader++] = Reader.release();
+  }
+  return NumReader;
+}
+
+llvm::SmallVector<APINotesReader *, 2>
+APINotesManager::findAPINotes(SourceLocation Loc) {
+  llvm::SmallVector<APINotesReader *, 2> Results;
+
+  // If there are readers for the current module, return them.
+  if (!getCurrentModuleReaders().empty()) {
+    Results.append(getCurrentModuleReaders().begin(),
+                   getCurrentModuleReaders().end());
+    return Results;
+  }
+
+  // If we're not allowed to implicitly load API notes files, we're done.
+  if (!ImplicitAPINotes)
+    return Results;
+
+  // If we don't have source location information, we're done.
+  if (Loc.isInvalid())
+    return Results;
+
+  // API notes are associated with the expansion location. Retrieve the
+  // file for this location.
+  SourceLocation ExpansionLoc = SM.getExpansionLoc(Loc);
+  FileID ID = SM.getFileID(ExpansionLoc);
+  if (ID.isInvalid())
+    return Results;
+  OptionalFileEntryRef File = SM.getFileEntryRefForID(ID);
+  if (!File)
+    return Results;
+
+  // Look for API notes in the directory corresponding to this file, or one of
+  // its its parent directories.
+  OptionalDirectoryEntryRef Dir = File->getDir();
+  FileManager &FileMgr = SM.getFileManager();
+  llvm::SetVector<const DirectoryEntry *,
+                  SmallVector<const DirectoryEntry *, 4>,
+                  llvm::SmallPtrSet<const DirectoryEntry *, 4>>
+      DirsVisited;
+  do {
+    // Look for an API notes reader for this header search directory.
+    auto Known = Readers.find(*Dir);
+
+    // If we already know the answer, chase it.
+    if (Known != Readers.end()) {
+      ++NumDirectoryCacheHits;
+
+      // We've been redirected to another directory for answers. Follow it.
+      if (Known->second && Known->second.is<DirectoryEntryRef>()) {
+        DirsVisited.insert(*Dir);
+        Dir = Known->second.get<DirectoryEntryRef>();
+        continue;
+      }
+
+      // We have the answer.
+      if (auto Reader = Known->second.dyn_cast<APINotesReader *>())
+        Results.push_back(Reader);
+      break;
+    }
+
+    // Look for API notes corresponding to this directory.
+    StringRef Path = Dir->getName();
+    if (llvm::sys::path::extension(Path) == ".framework") {
+      // If this is a framework directory, check whether there are API notes
+      // in the APINotes subdirectory.
+      auto FrameworkName = llvm::sys::path::stem(Path);
+      ++NumFrameworksSearched;
+
+      // Look for API notes for both the public and private headers.
+      OptionalDirectoryEntryRef PublicDir =
+          loadFrameworkAPINotes(Path, FrameworkName, /*Public=*/true);
+      OptionalDirectoryEntryRef PrivateDir =
+          loadFrameworkAPINotes(Path, FrameworkName, /*Public=*/false);
+
+      if (PublicDir || PrivateDir) {
+        // We found API notes: don't ever look past the framework directory.
+        Readers[*Dir] = nullptr;
+
+        // Pretend we found the result in the public or private directory,
+        // as appropriate. All headers should be in one of those two places,
+        // but be defensive here.
+        if (!DirsVisited.empty()) {
+          if (PublicDir && DirsVisited.back() == *PublicDir) {
+            DirsVisited.pop_back();
+            Dir = *PublicDir;
+          } else if (PrivateDir && DirsVisited.back() == *PrivateDir) {
+            DirsVisited.pop_back();
+            Dir = *PrivateDir;
+          }
+        }
+
+        // Grab the result.
+        if (auto Reader = Readers[*Dir].dyn_cast<APINotesReader *>())
+          Results.push_back(Reader);
+        break;
+      }
+    } else {
+      // Look for an APINotes file in this directory.
+      llvm::SmallString<128> APINotesPath(Dir->getName());
+      llvm::sys::path::append(
+          APINotesPath, (llvm::Twine("APINotes.") + SOURCE_APINOTES_EXTENSION));
+
+      // If there is an API notes file here, try to load it.
+      ++NumDirectoriesSearched;
+      if (auto APINotesFile = FileMgr.getOptionalFileRef(APINotesPath)) {
+        if (!loadAPINotes(*Dir, *APINotesFile)) {
+          ++NumHeaderAPINotes;
+          if (auto Reader = Readers[*Dir].dyn_cast<APINotesReader *>())
+            Results.push_back(Reader);
+          break;
+        }
+      }
+    }
+
+    // We didn't find anything. Look at the parent directory.
+    if (!DirsVisited.insert(*Dir)) {
+      Dir = std::nullopt;
+      break;
+    }
+
+    StringRef ParentPath = llvm::sys::path::parent_path(Path);
+    while (llvm::sys::path::stem(ParentPath) == "..")
+      ParentPath = llvm::sys::path::parent_path(ParentPath);
+
+    Dir = ParentPath.empty() ? std::nullopt
+                             : FileMgr.getOptionalDirectoryRef(ParentPath);
+  } while (Dir);
+
+  // Path compression for all of the directories we visited, redirecting
+  // them to the directory we ended on. If no API notes were found, the
+  // resulting directory will be NULL, indicating no API notes.
+  for (const auto Visited : DirsVisited)
+    Readers[Visited] = Dir ? ReaderEntry(*Dir) : ReaderEntry();
+
+  return Results;
+}
diff --git a/clang/lib/APINotes/CMakeLists.txt b/clang/lib/APINotes/CMakeLists.txt
index dec596e..dc83edd 100644
--- a/clang/lib/APINotes/CMakeLists.txt
+++ b/clang/lib/APINotes/CMakeLists.txt
@@ -3,6 +3,7 @@ set(LLVM_LINK_COMPONENTS
   BitstreamReader
   Support)
 add_clang_library(clangAPINotes
+  APINotesManager.cpp
   APINotesReader.cpp
   APINotesTypes.cpp
   APINotesWriter.cpp