[APINotes] Introduce APINotes infrastructure in Clang Sema and Frontend

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 initial Clang APINotes infrastructure to Clang Sema and
Clang Frontend.

There will shortly be a follow-up patch with the actual usages of this
API. I'm splitting these changes into separate PRs to keep the diffs
easier to review.

Author: egorzhdan

clang/include/clang/Frontend/CompilerInstance.h

@@ -304,6 +304,11 @@ class CompilerInstance : public ModuleLoader {
     return Invocation->getHeaderSearchOptsPtr();
   }
 
+  APINotesOptions &getAPINotesOpts() { return Invocation->getAPINotesOpts(); }
+  const APINotesOptions &getAPINotesOpts() const {
+    return Invocation->getAPINotesOpts();
+  }
+
   LangOptions &getLangOpts() { return Invocation->getLangOpts(); }
   const LangOptions &getLangOpts() const { return Invocation->getLangOpts(); }
 

clang/include/clang/Sema/Sema.h

@@ -14,6 +14,7 @@
 #ifndef LLVM_CLANG_SEMA_SEMA_H
 #define LLVM_CLANG_SEMA_SEMA_H
 
+#include "clang/APINotes/APINotesManager.h"
 #include "clang/AST/ASTConcept.h"
 #include "clang/AST/ASTFwd.h"
 #include "clang/AST/Attr.h"
@@ -408,6 +409,7 @@ class Sema final {
   ASTConsumer &Consumer;
   DiagnosticsEngine &Diags;
   SourceManager &SourceMgr;
+  api_notes::APINotesManager APINotes;
 
   /// Flag indicating whether or not to collect detailed statistics.
   bool CollectStats;

clang/lib/Frontend/CMakeLists.txt

@@ -48,6 +48,7 @@ add_clang_library(clangFrontend
   intrinsics_gen
 
   LINK_LIBS
+  clangAPINotes
   clangAST
   clangBasic
   clangDriver

clang/lib/Frontend/CompilerInstance.cpp

@@ -747,6 +747,10 @@ void CompilerInstance::createSema(TranslationUnitKind TUKind,
                                   CodeCompleteConsumer *CompletionConsumer) {
   TheSema.reset(new Sema(getPreprocessor(), getASTContext(), getASTConsumer(),
                          TUKind, CompletionConsumer));
+
+  // Set up API notes.
+  TheSema->APINotes.setSwiftVersion(getAPINotesOpts().SwiftVersion);
+
   // Attach the external sema source if there is any.
   if (ExternalSemaSrc) {
     TheSema->addExternalSource(ExternalSemaSrc.get());

clang/lib/Sema/CMakeLists.txt

@@ -74,6 +74,7 @@ add_clang_library(clangSema
   ClangDriverOptions
 
   LINK_LIBS
+  clangAPINotes
   clangAST
   clangAnalysis
   clangBasic

clang/lib/Sema/Sema.cpp

@@ -191,7 +191,8 @@ Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
     : ExternalSource(nullptr), CurFPFeatures(pp.getLangOpts()),
       LangOpts(pp.getLangOpts()), PP(pp), Context(ctxt), Consumer(consumer),
       Diags(PP.getDiagnostics()), SourceMgr(PP.getSourceManager()),
-      CollectStats(false), CodeCompleter(CodeCompleter), CurContext(nullptr),
+      APINotes(SourceMgr, LangOpts), CollectStats(false),
+      CodeCompleter(CodeCompleter), CurContext(nullptr),
       OriginalLexicalContext(nullptr), MSStructPragmaOn(false),
       MSPointerToMemberRepresentationMethod(
           LangOpts.getMSPointerToMemberRepresentationMethod()),