Reenable external categories (llvm#87357)

Reenables b31414b.

Also adds a new warning for missing `--symbol-graph-dir` arg when
`--emit-extension-symbol-graphs` is provided. This also reverts the
commit that removed.

Author: daniel-grumberg

clang/include/clang/Basic/DiagnosticDriverKinds.td

@@ -548,6 +548,12 @@ def err_drv_extract_api_wrong_kind : Error<
   "header file '%0' input '%1' does not match the type of prior input "
   "in api extraction; use '-x %2' to override">;
 
+def err_drv_missing_symbol_graph_dir: Error<
+  "Must provide a symbol graph output directory using --symbol-graph-dir=<directory>">;
+
+def err_drv_unexpected_symbol_graph_output : Error<
+  "Unexpected output symbol graph '%1'; please provide --symbol-graph-dir=<directory> instead">;
+
 def warn_slash_u_filename : Warning<"'/U%0' treated as the '/U' option">,
   InGroup<DiagGroup<"slash-u-filename">>;
 def note_use_dashdash : Note<

clang/include/clang/Basic/DiagnosticFrontendKinds.td

@@ -366,4 +366,8 @@ def warn_profile_data_misexpect : Warning<
 def err_extract_api_ignores_file_not_found :
   Error<"file '%0' specified by '--extract-api-ignores=' not found">, DefaultFatal;
 
+def warn_missing_symbol_graph_dir : Warning<
+  "Missing symbol graph output directory, defaulting to working directory">,
+  InGroup<ExtractAPIMisuse>;
+
 }

clang/include/clang/Basic/DiagnosticGroups.td

@@ -1517,3 +1517,5 @@ def UnsafeBufferUsage : DiagGroup<"unsafe-buffer-usage", [UnsafeBufferUsageInCon
 // Warnings and notes InstallAPI verification.
 def InstallAPIViolation : DiagGroup<"installapi-violation">;
 
+// Warnings about misuse of ExtractAPI options.
+def ExtractAPIMisuse : DiagGroup<"extractapi-misuse">;

clang/include/clang/Driver/Options.td

@@ -1507,14 +1507,29 @@ def extract_api : Flag<["-"], "extract-api">,
 def product_name_EQ: Joined<["--"], "product-name=">,
   Visibility<[ClangOption, CC1Option]>,
   MarshallingInfoString<FrontendOpts<"ProductName">>;
-def emit_symbol_graph_EQ: JoinedOrSeparate<["--"], "emit-symbol-graph=">,
+def emit_symbol_graph: Flag<["-"], "emit-symbol-graph">,
   Visibility<[ClangOption, CC1Option]>,
-    HelpText<"Generate Extract API information as a side effect of compilation.">,
-    MarshallingInfoString<FrontendOpts<"SymbolGraphOutputDir">>;
+  HelpText<"Generate Extract API information as a side effect of compilation.">,
+  MarshallingInfoFlag<FrontendOpts<"EmitSymbolGraph">>;
+def emit_extension_symbol_graphs: Flag<["--"], "emit-extension-symbol-graphs">,
+  Visibility<[ClangOption, CC1Option]>,
+  HelpText<"Generate additional symbol graphs for extended modules.">,
+  MarshallingInfoFlag<FrontendOpts<"EmitExtensionSymbolGraphs">>;
 def extract_api_ignores_EQ: CommaJoined<["--"], "extract-api-ignores=">,
   Visibility<[ClangOption, CC1Option]>,
     HelpText<"Comma separated list of files containing a new line separated list of API symbols to ignore when extracting API information.">,
     MarshallingInfoStringVector<FrontendOpts<"ExtractAPIIgnoresFileList">>;
+def symbol_graph_dir_EQ: Joined<["--"], "symbol-graph-dir=">,
+   Visibility<[ClangOption, CC1Option]>,
+   HelpText<"Directory in which to emit symbol graphs.">,
+   MarshallingInfoString<FrontendOpts<"SymbolGraphOutputDir">>;
+def emit_pretty_sgf: Flag<["--"], "pretty-sgf">,
+    Visibility<[ClangOption, CC1Option]>,
+    HelpText<"Emit pretty printed symbol graphs">,
+    MarshallingInfoFlag<FrontendOpts<"EmitPrettySymbolGraphs">>;
+def emit_sgf_symbol_labels_for_testing: Flag<["--"], "emit-sgf-symbol-labels-for-testing">,
+   Visibility<[CC1Option]>,
+   MarshallingInfoFlag<FrontendOpts<"EmitSymbolGraphSymbolLabelsForTesting">>;
 def e : Separate<["-"], "e">, Flags<[LinkerInput]>, Group<Link_Group>;
 def fmax_tokens_EQ : Joined<["-"], "fmax-tokens=">, Group<f_Group>,
   Visibility<[ClangOption, CC1Option]>,