From 05ca21cd313d6ada5dc33cf56ed348cb47f37810 Mon Sep 17 00:00:00 2001
From: Owen Voorhees <ovoorhees@apple.com>
Date: Thu, 11 Dec 2025 12:27:55 -0800
Subject: [PATCH] API digester support for Xcc options

---
 include/swift/Option/Options.td                   |  2 +-
 lib/DriverTool/swift_api_digester_main.cpp        |  7 +++++++
 lib/Option/features.json                          |  3 +++
 test/api-digester/Inputs/XccTest/XccTest.h        |  9 +++++++++
 test/api-digester/Inputs/XccTest/module.modulemap |  4 ++++
 test/api-digester/Xcc-preprocessor-define.swift   | 13 +++++++++++++
 6 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 test/api-digester/Inputs/XccTest/XccTest.h
 create mode 100644 test/api-digester/Inputs/XccTest/module.modulemap
 create mode 100644 test/api-digester/Xcc-preprocessor-define.swift

diff --git a/include/swift/Option/Options.td b/include/swift/Option/Options.td
index c9ae020129f97..abc06ad0de710 100644
--- a/include/swift/Option/Options.td
+++ b/include/swift/Option/Options.td
@@ -1556,7 +1556,7 @@ def Xfrontend : Separate<["-"], "Xfrontend">, Flags<[HelpHidden]>,
 
 def Xcc : Separate<["-"], "Xcc">,
   Flags<[FrontendOption, SwiftSymbolGraphExtractOption,
-         SwiftSynthesizeInterfaceOption]>,
+         SwiftSynthesizeInterfaceOption, SwiftAPIDigesterOption]>,
   MetaVarName<"<arg>">,
   HelpText<"Pass <arg> to the C/C++/Objective-C compiler">;
 
diff --git a/lib/DriverTool/swift_api_digester_main.cpp b/lib/DriverTool/swift_api_digester_main.cpp
index 777d141c6ed44..ef778c59ca005 100644
--- a/lib/DriverTool/swift_api_digester_main.cpp
+++ b/lib/DriverTool/swift_api_digester_main.cpp
@@ -2273,6 +2273,7 @@ class SwiftAPIDigesterInvocation {
   std::string ResourceDir;
   std::string ModuleCachePath;
   bool DisableFailOnError;
+  std::vector<std::string> ClangImporterArgs;
 
 public:
   SwiftAPIDigesterInvocation(const std::string &ExecPath)
@@ -2375,6 +2376,7 @@ class SwiftAPIDigesterInvocation {
         ParsedArgs.getAllArgValues(OPT_use_interface_for_module);
     ResourceDir = ParsedArgs.getLastArgValue(OPT_resource_dir).str();
     ModuleCachePath = ParsedArgs.getLastArgValue(OPT_module_cache_path).str();
+    ClangImporterArgs = ParsedArgs.getAllArgValues(OPT_Xcc);
     DebugMapping = ParsedArgs.hasArg(OPT_debug_mapping);
     DisableFailOnError = ParsedArgs.hasArg(OPT_disable_fail_on_error);
 
@@ -2456,6 +2458,11 @@ class SwiftAPIDigesterInvocation {
         InitInvoke.getLangOptions().Target.isOSDarwin();
     InitInvoke.getClangImporterOptions().ModuleCachePath = ModuleCachePath;
 
+    // Pass -Xcc arguments to the Clang importer
+    for (const auto &arg : ClangImporterArgs) {
+      InitInvoke.getClangImporterOptions().ExtraArgs.push_back(arg);
+    }
+
     if (!SwiftVersion.empty()) {
       using version::Version;
       bool isValid = false;
diff --git a/lib/Option/features.json b/lib/Option/features.json
index 7d521787a4dd8..554868bb3b4f9 100644
--- a/lib/Option/features.json
+++ b/lib/Option/features.json
@@ -53,6 +53,9 @@
     },
     {
        "name": "internal-import-bridging-header"
+    },
+    {
+       "name": "api-digester-Xcc"
     }
   ]
 }
diff --git a/test/api-digester/Inputs/XccTest/XccTest.h b/test/api-digester/Inputs/XccTest/XccTest.h
new file mode 100644
index 0000000000000..bd571ae5a2120
--- /dev/null
+++ b/test/api-digester/Inputs/XccTest/XccTest.h
@@ -0,0 +1,9 @@
+@import ObjectiveC;
+
+#ifdef MY_MACRO
+@interface Hidden : NSObject
+@end
+#endif
+
+@interface NotHidden : NSObject
+@end
diff --git a/test/api-digester/Inputs/XccTest/module.modulemap b/test/api-digester/Inputs/XccTest/module.modulemap
new file mode 100644
index 0000000000000..f51c5875e1452
--- /dev/null
+++ b/test/api-digester/Inputs/XccTest/module.modulemap
@@ -0,0 +1,4 @@
+module XccTest {
+  header "XccTest.h"
+  export *
+}
diff --git a/test/api-digester/Xcc-preprocessor-define.swift b/test/api-digester/Xcc-preprocessor-define.swift
new file mode 100644
index 0000000000000..ffb34bd9569c0
--- /dev/null
+++ b/test/api-digester/Xcc-preprocessor-define.swift
@@ -0,0 +1,13 @@
+// REQUIRES: VENDOR=apple
+
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t.module-cache)
+
+// RUN: %api-digester -dump-sdk -module XccTest -o %t.with-define.json -module-cache-path %t.module-cache %clang-importer-sdk-nosource -I %S/Inputs/XccTest -Xcc -DMY_MACRO
+// RUN: %api-digester -dump-sdk -module XccTest -o %t.without-define.json -module-cache-path %t.module-cache %clang-importer-sdk-nosource -I %S/Inputs/XccTest
+
+// RUN: grep -q "Hidden" %t.with-define.json
+// RUN: grep -q "NotHidden" %t.with-define.json
+
+// RUN: not grep -q "Hidden" %t.without-define.json
+// RUN: grep -q "NotHidden" %t.without-define.json
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