[PrintAsObjC] Defend against macros named 'any' (#12396)

SourceKit uses a clever pragma to automatically attach an attribute to
every declaration in the file. However, the form of this pragma (clang
attribute push) uses a parenthesized list marked with 'any', which turns
out to be a name that people sometimes use for macros. Guard against this
using the push_macro pragma (originally from MSVC), under the assumption
that anyone who supports the highly-use-specific 'external_source_symbol'
attribute probably implements this more common extension. This does make
the generated header a little uglier, but it's not like it was really
pretty to begin with.

rdar://problem/34168022

Author: jrose-apple

lib/PrintAsObjC/PrintAsObjC.cpp

@@ -2371,21 +2371,6 @@ class ModuleWriter {
            "# define __has_warning(x) 0\n"
            "#endif\n"
            "\n"
-           "#if __has_attribute(external_source_symbol)\n"
-           "# define SWIFT_STRINGIFY(str) #str\n"
-           "# define SWIFT_MODULE_NAMESPACE_PUSH(module_name) "
-             "_Pragma(SWIFT_STRINGIFY(clang attribute "
-             "push(__attribute__((external_source_symbol(language=\"Swift\", "
-             "defined_in=module_name, generated_declaration))), "
-             "apply_to=any(function, enum, objc_interface, objc_category, "
-             "objc_protocol))))\n"
-           "# define SWIFT_MODULE_NAMESPACE_POP "
-             "_Pragma(\"clang attribute pop\")\n"
-           "#else\n"
-           "# define SWIFT_MODULE_NAMESPACE_PUSH(module_name)\n"
-           "# define SWIFT_MODULE_NAMESPACE_POP\n"
-           "#endif\n"
-           "\n"
            "#if __has_include(<swift/objc-prologue.h>)\n"
            "# include <swift/objc-prologue.h>\n"
            "#endif\n"
@@ -2749,9 +2734,20 @@ class ModuleWriter {
         "#pragma clang diagnostic ignored \"-Wunknown-pragmas\"\n"
         "#pragma clang diagnostic ignored \"-Wnullability\"\n"
         "\n"
-        "SWIFT_MODULE_NAMESPACE_PUSH(\"" << M.getNameStr() << "\")\n"
+        "#if __has_attribute(external_source_symbol)\n"
+        "# pragma push_macro(\"any\")\n"
+        "# undef any\n"
+        "# pragma clang attribute push("
+          "__attribute__((external_source_symbol(language=\"Swift\", "
+            "defined_in=\"" << M.getNameStr() << "\",generated_declaration))), "
+          "apply_to=any(function,enum,objc_interface,objc_category,"
+             "objc_protocol))\n"
+        "# pragma pop_macro(\"any\")\n"
+        "#endif\n\n"
       << os.str()
-      << "SWIFT_MODULE_NAMESPACE_POP\n"
+      << "#if __has_attribute(external_source_symbol)\n"
+         "# pragma clang attribute pop\n"
+         "#endif\n"
          "#pragma clang diagnostic pop\n";
     return false;
   }

test/PrintAsObjC/Inputs/comments-expected-output.h

@@ -451,5 +451,7 @@ SWIFT_CLASS("_TtC8comments13UnorderedList")
 - (nonnull instancetype)init OBJC_DESIGNATED_INITIALIZER;
 @end
 
-SWIFT_MODULE_NAMESPACE_POP
+#if __has_attribute(external_source_symbol)
+# pragma clang attribute pop
+#endif
 #pragma clang diagnostic pop

test/PrintAsObjC/interfering-macros.swift

@@ -0,0 +1,19 @@
+// RUN: %empty-directory(%t)
+
+// FIXME: BEGIN -enable-source-import hackaround
+// RUN:  %target-swift-frontend(mock-sdk: -sdk %S/../Inputs/clang-importer-sdk -I %t) -emit-module -o %t %S/../Inputs/clang-importer-sdk/swift-modules/ObjectiveC.swift
+// RUN:  %target-swift-frontend(mock-sdk: -sdk %S/../Inputs/clang-importer-sdk -I %t) -emit-module -o %t %S/../Inputs/clang-importer-sdk/swift-modules/CoreGraphics.swift
+// RUN:  %target-swift-frontend(mock-sdk: -sdk %S/../Inputs/clang-importer-sdk -I %t) -emit-module -o %t %S/../Inputs/clang-importer-sdk/swift-modules/Foundation.swift
+// FIXME: END -enable-source-import hackaround
+
+// RUN: %target-swift-frontend(mock-sdk: -sdk %S/../Inputs/clang-importer-sdk -I %t) %s -typecheck -emit-objc-header-path %t/interfering-macros.h
+// RUN: %check-in-clang -fsyntax-only -Werror %t/interfering-macros.h -D'any=UNWANTED_MACRO_SUBSTITUTION'
+
+// REQUIRES: objc_interop
+
+import Foundation
+
+@objc public class Test : NSObject {
+  public var str: String = ""
+  public var strongProp: Any?
+}