[APINotes] Upstream APINotesOptions

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

This adds the first compiler options related to API Notes to the
upstream Clang: `-iapinotes-modules` and `-fapinotes-swift-version=`.
However, this does not add the `-fapinotes` flag that enables API Notes,
since the feature is not fully functional yet.

clang/include/clang/APINotes/APINotesOptions.h

@@ -0,0 +1,34 @@
+//===--- APINotesOptions.h --------------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_APINOTES_APINOTESOPTIONS_H
+#define LLVM_CLANG_APINOTES_APINOTESOPTIONS_H
+
+#include "llvm/Support/VersionTuple.h"
+#include <string>
+#include <vector>
+
+namespace clang {
+
+/// Tracks various options which control how API notes are found and handled.
+class APINotesOptions {
+public:
+  /// The Swift version which should be used for API notes.
+  llvm::VersionTuple SwiftVersion;
+
+  /// The set of search paths where we API notes can be found for particular
+  /// modules.
+  ///
+  /// The API notes in this directory are stored as <ModuleName>.apinotes, and
+  /// are only applied when building the module <ModuleName>.
+  std::vector<std::string> ModuleSearchPaths;
+};
+
+} // namespace clang
+
+#endif // LLVM_CLANG_APINOTES_APINOTESOPTIONS_H

clang/include/clang/Driver/Options.td

@@ -1733,6 +1733,10 @@ def fswift_async_fp_EQ : Joined<["-"], "fswift-async-fp=">,
     NormalizedValuesScope<"CodeGenOptions::SwiftAsyncFramePointerKind">,
     NormalizedValues<["Auto", "Always", "Never"]>,
     MarshallingInfoEnum<CodeGenOpts<"SwiftAsyncFramePointer">, "Always">;
+def fapinotes_swift_version : Joined<["-"], "fapinotes-swift-version=">,
+  Group<f_clang_Group>, Visibility<[ClangOption, CC1Option]>,
+  MetaVarName<"<version>">,
+  HelpText<"Specify the Swift version to use when filtering API notes">;
 
 defm addrsig : BoolFOption<"addrsig",
   CodeGenOpts<"Addrsig">, DefaultFalse,
@@ -4129,6 +4133,9 @@ def ibuiltininc : Flag<["-"], "ibuiltininc">, Group<clang_i_Group>,
 def index_header_map : Flag<["-"], "index-header-map">,
   Visibility<[ClangOption, CC1Option]>,
   HelpText<"Make the next included directory (-I or -F) an indexer header map">;
+def iapinotes_modules : JoinedOrSeparate<["-"], "iapinotes-modules">, Group<clang_i_Group>,
+  Visibility<[ClangOption, CC1Option]>,
+  HelpText<"Add directory to the API notes search path referenced by module name">, MetaVarName<"<directory>">;
 def idirafter : JoinedOrSeparate<["-"], "idirafter">, Group<clang_i_Group>,
   Visibility<[ClangOption, CC1Option]>,
   HelpText<"Add directory to AFTER include search path">;

clang/include/clang/Frontend/CompilerInvocation.h

@@ -9,6 +9,7 @@
 #ifndef LLVM_CLANG_FRONTEND_COMPILERINVOCATION_H
 #define LLVM_CLANG_FRONTEND_COMPILERINVOCATION_H
 
+#include "clang/APINotes/APINotesOptions.h"
 #include "clang/Basic/CodeGenOptions.h"
 #include "clang/Basic/DiagnosticOptions.h"
 #include "clang/Basic/FileSystemOptions.h"
@@ -92,6 +93,9 @@ class CompilerInvocationBase {
 
   std::shared_ptr<MigratorOptions> MigratorOpts;
 
+  /// Options controlling API notes.
+  std::shared_ptr<APINotesOptions> APINotesOpts;
+
   /// Options controlling IRgen and the backend.
   std::shared_ptr<CodeGenOptions> CodeGenOpts;
 
@@ -131,6 +135,7 @@ class CompilerInvocationBase {
   const PreprocessorOptions &getPreprocessorOpts() const { return *PPOpts; }
   const AnalyzerOptions &getAnalyzerOpts() const { return *AnalyzerOpts; }
   const MigratorOptions &getMigratorOpts() const { return *MigratorOpts; }
+  const APINotesOptions &getAPINotesOpts() const { return *APINotesOpts; }
   const CodeGenOptions &getCodeGenOpts() const { return *CodeGenOpts; }
   const FileSystemOptions &getFileSystemOpts() const { return *FSOpts; }
   const FrontendOptions &getFrontendOpts() const { return *FrontendOpts; }
@@ -242,6 +247,7 @@ class CompilerInvocation : public CompilerInvocationBase {
   PreprocessorOptions &getPreprocessorOpts() { return *PPOpts; }
   AnalyzerOptions &getAnalyzerOpts() { return *AnalyzerOpts; }
   MigratorOptions &getMigratorOpts() { return *MigratorOpts; }
+  APINotesOptions &getAPINotesOpts() { return *APINotesOpts; }
   CodeGenOptions &getCodeGenOpts() { return *CodeGenOpts; }
   FileSystemOptions &getFileSystemOpts() { return *FSOpts; }
   FrontendOptions &getFrontendOpts() { return *FrontendOpts; }

clang/lib/Frontend/CompilerInvocation.cpp

@@ -3261,6 +3261,17 @@ static bool ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args,
   return Diags.getNumErrors() == NumErrorsBefore;
 }
 
+static void ParseAPINotesArgs(APINotesOptions &Opts, ArgList &Args,
+                              DiagnosticsEngine &diags) {
+  if (const Arg *A = Args.getLastArg(OPT_fapinotes_swift_version)) {
+    if (Opts.SwiftVersion.tryParse(A->getValue()))
+      diags.Report(diag::err_drv_invalid_value)
+          << A->getAsString(Args) << A->getValue();
+  }
+  for (const Arg *A : Args.filtered(OPT_iapinotes_modules))
+    Opts.ModuleSearchPaths.push_back(A->getValue());
+}
+
 /// Check if input file kind and language standard are compatible.
 static bool IsInputCompatibleWithStandard(InputKind IK,
                                           const LangStandard &S) {
@@ -4538,6 +4549,7 @@ bool CompilerInvocation::CreateFromArgsImpl(
   llvm::Triple T(Res.getTargetOpts().Triple);
   ParseHeaderSearchArgs(Res.getHeaderSearchOpts(), Args, Diags,
                         Res.getFileSystemOpts().WorkingDir);
+  ParseAPINotesArgs(Res.getAPINotesOpts(), Args, Diags);
 
   ParseLangArgs(LangOpts, Args, DashX, T, Res.getPreprocessorOpts().Includes,
                 Diags);