[APINotes] Upstream Driver and Frontend options that enable API Notes

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

Author: egorzhdan

clang/include/clang/Basic/LangOptions.def

@@ -405,6 +405,7 @@ LANGOPT(XLPragmaPack, 1, 0, "IBM XL #pragma pack handling")
 LANGOPT(RetainCommentsFromSystemHeaders, 1, 0, "retain documentation comments from system headers in the AST")
 
 LANGOPT(APINotes, 1, 0, "use external API notes")
+LANGOPT(APINotesModules, 1, 0, "use module-based external API notes")
 
 LANGOPT(SanitizeAddressFieldPadding, 2, 0, "controls how aggressive is ASan "
                                            "field padding (0: none, 1:least "

clang/include/clang/Driver/Options.td

@@ -1754,6 +1754,18 @@ def fswift_async_fp_EQ : Joined<["-"], "fswift-async-fp=">,
     NormalizedValuesScope<"CodeGenOptions::SwiftAsyncFramePointerKind">,
     NormalizedValues<["Auto", "Always", "Never"]>,
     MarshallingInfoEnum<CodeGenOpts<"SwiftAsyncFramePointer">, "Always">;
+defm apinotes : BoolOption<"f", "apinotes",
+    LangOpts<"APINotes">, DefaultFalse,
+    PosFlag<SetTrue, [], [ClangOption], "Enable">,
+    NegFlag<SetFalse, [], [ClangOption], "Disable">,
+    BothFlags<[], [ClangOption, CC1Option], "external API notes support">>,
+    Group<f_clang_Group>;
+defm apinotes_modules : BoolOption<"f", "apinotes-modules",
+    LangOpts<"APINotesModules">, DefaultFalse,
+    PosFlag<SetTrue, [], [ClangOption], "Enable">,
+    NegFlag<SetFalse, [], [ClangOption], "Disable">,
+    BothFlags<[], [ClangOption, CC1Option], "module-based external API notes support">>,
+    Group<f_clang_Group>;
 def fapinotes_swift_version : Joined<["-"], "fapinotes-swift-version=">,
   Group<f_clang_Group>, Visibility<[ClangOption, CC1Option]>,
   MetaVarName<"<version>">,

clang/lib/Driver/ToolChains/Clang.cpp

@@ -6720,6 +6720,13 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   Args.addOptOutFlag(CmdArgs, options::OPT_fassume_sane_operator_new,
                      options::OPT_fno_assume_sane_operator_new);
 
+  if (Args.hasFlag(options::OPT_fapinotes, options::OPT_fno_apinotes, false))
+    CmdArgs.push_back("-fapinotes");
+  if (Args.hasFlag(options::OPT_fapinotes_modules,
+                   options::OPT_fno_apinotes_modules, false))
+    CmdArgs.push_back("-fapinotes-modules");
+  Args.AddLastArg(CmdArgs, options::OPT_fapinotes_swift_version);
+
   // -fblocks=0 is default.
   if (Args.hasFlag(options::OPT_fblocks, options::OPT_fno_blocks,
                    TC.IsBlocksDefault()) ||

clang/lib/Frontend/CompilerInstance.cpp

@@ -756,6 +756,14 @@ void CompilerInstance::createSema(TranslationUnitKind TUKind,
     TheSema->addExternalSource(ExternalSemaSrc.get());
     ExternalSemaSrc->InitializeSema(*TheSema);
   }
+
+  // If we're building a module and are supposed to load API notes,
+  // notify the API notes manager.
+  if (auto *currentModule = getPreprocessor().getCurrentModule()) {
+    (void)TheSema->APINotes.loadCurrentModuleAPINotes(
+        currentModule, getLangOpts().APINotesModules,
+        getAPINotesOpts().ModuleSearchPaths);
+  }
 }
 
 // Output Files

clang/lib/Frontend/CompilerInvocation.cpp

@@ -3267,6 +3267,16 @@ static bool ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args,
   return Diags.getNumErrors() == NumErrorsBefore;
 }
 
+static void GenerateAPINotesArgs(const APINotesOptions &Opts,
+                                 ArgumentConsumer Consumer) {
+  if (!Opts.SwiftVersion.empty())
+    GenerateArg(Consumer, OPT_fapinotes_swift_version,
+                Opts.SwiftVersion.getAsString());
+
+  for (const auto &Path : Opts.ModuleSearchPaths)
+    GenerateArg(Consumer, OPT_iapinotes_modules, Path);
+}
+
 static void ParseAPINotesArgs(APINotesOptions &Opts, ArgList &Args,
                               DiagnosticsEngine &diags) {
   if (const Arg *A = Args.getLastArg(OPT_fapinotes_swift_version)) {
@@ -4746,6 +4756,18 @@ std::string CompilerInvocation::getModuleHash() const {
   for (const auto &ext : getFrontendOpts().ModuleFileExtensions)
     ext->hashExtension(HBuilder);
 
+  // Extend the signature with the Swift version for API notes.
+  const APINotesOptions &APINotesOpts = getAPINotesOpts();
+  if (!APINotesOpts.SwiftVersion.empty()) {
+    HBuilder.add(APINotesOpts.SwiftVersion.getMajor());
+    if (auto Minor = APINotesOpts.SwiftVersion.getMinor())
+      HBuilder.add(*Minor);
+    if (auto Subminor = APINotesOpts.SwiftVersion.getSubminor())
+      HBuilder.add(*Subminor);
+    if (auto Build = APINotesOpts.SwiftVersion.getBuild())
+      HBuilder.add(*Build);
+  }
+
   // When compiling with -gmodules, also hash -fdebug-prefix-map as it
   // affects the debug info in the PCM.
   if (getCodeGenOpts().DebugTypeExtRefs)
@@ -4776,6 +4798,7 @@ void CompilerInvocationBase::generateCC1CommandLine(
   GenerateFrontendArgs(getFrontendOpts(), Consumer, getLangOpts().IsHeaderFile);
   GenerateTargetArgs(getTargetOpts(), Consumer);
   GenerateHeaderSearchArgs(getHeaderSearchOpts(), Consumer);
+  GenerateAPINotesArgs(getAPINotesOpts(), Consumer);
   GenerateLangArgs(getLangOpts(), Consumer, T, getFrontendOpts().DashX);
   GenerateCodeGenArgs(getCodeGenOpts(), Consumer, T,
                       getFrontendOpts().OutputFile, &getLangOpts());