Add option to provide an allow list of reexported modules for swift-symbolgraph-extract

Author: daniel-grumberg

include/swift/Option/Options.td

@@ -1573,6 +1573,10 @@ def output_dir : Separate<["-"], "output-dir">,
   HelpText<"Output directory">,
   MetaVarName<"<dir>">;
 
+def experimental_allowed_reexported_modules: CommaJoined<["-"], "experimental_allowed_reexported_modules">,
+  Flags<[NoDriverOption, SwiftSymbolGraphExtractOption]>,
+  HelpText<"Allow reexporting symbols from the provided modules if they are themselves exported from the main module. This is a comma separated list of module names.">;
+
 def skip_synthesized_members: Flag<[ "-" ], "skip-synthesized-members">,
   Flags<[NoDriverOption, SwiftSymbolGraphExtractOption]>,
   HelpText<"Skip members inherited through classes or default implementations">;

include/swift/SymbolGraphGen/SymbolGraphOptions.h

@@ -11,6 +11,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/TargetParser/Triple.h"
+#include "llvm/ADT/ArrayRef.h"
+
 #include "swift/AST/AttrKind.h"
 
 #ifndef SWIFT_SYMBOLGRAPHGEN_SYMBOLGRAPHOPTIONS_H
@@ -63,6 +65,10 @@ struct SymbolGraphOptions {
   /// but SourceKit should be able to load the information when pulling symbol
   /// information for individual queries.
   bool PrintPrivateStdlibSymbols = false;
+
+  /// If this has a value specifies an explicit allow list of reexported module
+  /// names that should be included symbol graph.
+  std::optional<llvm::ArrayRef<StringRef>> AllowedReexportedModules = {};
 };
 
 } // end namespace symbolgraphgen

lib/DriverTool/swift_symbolgraph_extract_main.cpp

@@ -163,6 +163,13 @@ int swift_symbolgraph_extract_main(ArrayRef<const char *> Args,
     }
   }
 
+  SmallVector<StringRef, 4> AllowedRexports;
+  if (auto *A =
+          ParsedArgs.getLastArg(OPT_experimental_allowed_reexported_modules)) {
+    for (const auto *val : A->getValues())
+      AllowedRexports.emplace_back(val);
+  }
+
   symbolgraphgen::SymbolGraphOptions Options;
   Options.OutputDir = OutputDir;
   Options.Target = Target;
@@ -175,6 +182,7 @@ int swift_symbolgraph_extract_main(ArrayRef<const char *> Args,
   Options.EmitExtensionBlockSymbols =
       ParsedArgs.hasFlag(OPT_emit_extension_block_symbols,
                          OPT_omit_extension_block_symbols, /*default=*/false);
+  Options.AllowedReexportedModules = AllowedRexports;
 
   if (auto *A = ParsedArgs.getLastArg(OPT_minimum_access_level)) {
     Options.MinimumAccessLevel =