[cxx-interop] Remove workarounds for CF_OPTIONS default arguments

ClangImporter has logic that infers default arguments of certain C/C++ types, such as the types declared via `CF_OPTIONS`/`NS_OPTIONS` macros.

There were some workarounds in place which triggered for C++ interop mode specifically. The workarounds were applying a heuristic based on the name of the type, which tried to match the behavior to non-C++ interop mode for certain types from the OS SDK. That was not working well for user-defined types, causing source compatibility breakages when enabling C++ interop.

This change replaces the name-based heuristic with a more robust criteria.

See also 3791ccb.

rdar://142961112

Author: egorzhdan

lib/ClangImporter/ImportEnumInfo.h

@@ -163,6 +163,11 @@ StringRef getCommonPluralPrefix(StringRef singular, StringRef plural);
 /// Returns the underlying integer type of an enum. If clang treats the type as
 /// an elaborated type, an unwrapped type is returned.
 const clang::Type *getUnderlyingType(const clang::EnumDecl *decl);
+
+inline bool isCFOptionsMacro(StringRef macroName) {
+  return macroName == "CF_OPTIONS" || macroName == "NS_OPTIONS";
+}
+
 }
 }
 

lib/ClangImporter/ImportName.cpp

@@ -1875,7 +1875,7 @@ ImportedName NameImporter::importNameImpl(const clang::NamedDecl *D,
     if (loc.isMacroID()) {
       StringRef macroName =
           clangSema.getPreprocessor().getImmediateMacroName(loc);
-      if (macroName == "CF_OPTIONS" || macroName == "NS_OPTIONS")
+      if (isCFOptionsMacro(macroName))
         return ImportedName();
     }
   }

lib/ClangImporter/ImportType.cpp

@@ -2919,42 +2919,24 @@ ArgumentAttrs ClangImporter::Implementation::inferDefaultArgument(
   } else if (const clang::TypedefType *typedefType =
                  type->getAs<clang::TypedefType>()) {
     // Get the AvailabilityAttr that would be set from CF/NS_OPTIONS
-    if (importer::isUnavailableInSwift(typedefType->getDecl(), nullptr, true)) {
+    auto typedefDecl = typedefType->getDecl();
+    if (importer::isUnavailableInSwift(typedefDecl, nullptr, true)) {
       // If we've taken this branch it means we have an enum type, and it is
       // likely an integer or NSInteger that is being used by NS/CF_OPTIONS to
       // behave like a C enum in the presence of C++.
-      auto enumName = typedefType->getDecl()->getName();
+      auto enumName = typedefDecl->getName();
       ArgumentAttrs argumentAttrs(DefaultArgumentKind::None, true, enumName);
-      auto camelCaseWords = camel_case::getWords(enumName);
-      for (auto it = camelCaseWords.rbegin(); it != camelCaseWords.rend();
-           ++it) {
-        auto word = *it;
-        auto next = std::next(it);
+      for (auto word : llvm::reverse(camel_case::getWords(enumName))) {
         if (camel_case::sameWordIgnoreFirstCase(word, "options")) {
           argumentAttrs.argumentKind = DefaultArgumentKind::EmptyArray;
           return argumentAttrs;
         }
-        if (camel_case::sameWordIgnoreFirstCase(word, "units"))
-          return argumentAttrs;
-        if (camel_case::sameWordIgnoreFirstCase(word, "domain"))
-          return argumentAttrs;
-        if (camel_case::sameWordIgnoreFirstCase(word, "action"))
-          return argumentAttrs;
-        if (camel_case::sameWordIgnoreFirstCase(word, "event"))
-          return argumentAttrs;
-        if (camel_case::sameWordIgnoreFirstCase(word, "events") &&
-            next != camelCaseWords.rend() &&
-            camel_case::sameWordIgnoreFirstCase(*next, "control"))
-          return argumentAttrs;
-        if (camel_case::sameWordIgnoreFirstCase(word, "state"))
-          return argumentAttrs;
-        if (camel_case::sameWordIgnoreFirstCase(word, "unit"))
-          return argumentAttrs;
-        if (camel_case::sameWordIgnoreFirstCase(word, "position") &&
-            next != camelCaseWords.rend() &&
-            camel_case::sameWordIgnoreFirstCase(*next, "scroll"))
-          return argumentAttrs;
-        if (camel_case::sameWordIgnoreFirstCase(word, "edge"))
+      }
+      auto loc = typedefDecl->getEndLoc();
+      if (loc.isMacroID()) {
+        StringRef macroName =
+            nameImporter.getClangPreprocessor().getImmediateMacroName(loc);
+        if (isCFOptionsMacro(macroName))
           return argumentAttrs;
       }
     }

test/Interop/Cxx/enum/Inputs/c-enums-withOptions-omit.h

@@ -1,43 +1,57 @@
+#include "CFAvailability.h"
+
+typedef unsigned long NSUInteger;
+
 // Enum usage that is bitwise-able and assignable in C++, aka how CF_OPTIONS
 // does things.
-typedef int __attribute__((availability(swift, unavailable))) NSEnumerationOptions;
-enum : NSEnumerationOptions { NSEnumerationConcurrent, NSEnumerationReverse };
+typedef CF_OPTIONS(NSUInteger, NSEnumerationOptions) {
+  NSEnumerationConcurrent = (1UL << 0),
+  NSEnumerationReverse = (1UL << 1),
+};
 
 @interface NSSet
 - (void)enumerateObjectsWithOptions:(NSEnumerationOptions)opts ;
 @end
 
-typedef int __attribute__((availability(swift, unavailable))) NSOrderedCollectionDifferenceCalculationOptions;
-enum : NSOrderedCollectionDifferenceCalculationOptions {
+typedef CF_OPTIONS(NSUInteger, NSOrderedCollectionDifferenceCalculationOptions) {
   NSOrderedCollectionDifferenceCalculationOptions1,
   NSOrderedCollectionDifferenceCalculationOptions2
 };
 
-typedef int __attribute__((availability(swift, unavailable))) NSCalendarUnit;
-enum : NSCalendarUnit { NSCalendarUnit1, NSCalendarUnit2 };
+typedef CF_OPTIONS(NSUInteger, NSCalendarUnit) {
+  NSCalendarUnit1,
+  NSCalendarUnit2
+};
 
-typedef int __attribute__((availability(swift, unavailable))) NSSearchPathDomainMask;
-enum : NSSearchPathDomainMask { NSSearchPathDomainMask1, NSSearchPathDomainMask2 };
+typedef CF_OPTIONS(NSUInteger, NSSearchPathDomainMask) {
+  NSSearchPathDomainMask1,
+  NSSearchPathDomainMask2
+};
 
-typedef int __attribute__((availability(swift, unavailable))) NSControlCharacterAction;
-enum : NSControlCharacterAction { NSControlCharacterAction1, NSControlCharacterAction2 };
+typedef CF_OPTIONS(NSUInteger, NSControlCharacterAction) {
+  NSControlCharacterAction1,
+  NSControlCharacterAction2
+};
 
-typedef int __attribute__((availability(swift, unavailable))) UIControlState;
-enum : UIControlState { UIControlState1, UIControlState2 };
+typedef CF_OPTIONS(NSUInteger, UIControlState) {
+  UIControlState1,
+  UIControlState2
+};
 
-typedef int __attribute__((availability(swift, unavailable))) UITableViewCellStateMask;
-enum : UITableViewCellStateMask { UITableViewCellStateMask1, UITableViewCellStateMask2 };
+typedef CF_OPTIONS(NSUInteger, UITableViewCellStateMask) {
+  UITableViewCellStateMask1,
+  UITableViewCellStateMask2
+};
 
-typedef int __attribute__((availability(swift, unavailable))) UIControlEvents;
-enum : UIControlEvents { UIControlEvents1, UIControlEvents2 };
+typedef CF_OPTIONS(NSUInteger, UIControlEvents) {
+  UIControlEvents1,
+  UIControlEvents2
+};
 
-typedef int __attribute__((availability(swift, unavailable)))
-UITableViewScrollPosition;
-enum : UITableViewScrollPosition {
+typedef CF_OPTIONS(NSUInteger, UITableViewScrollPosition) {
   UITableViewScrollPosition1,
   UITableViewScrollPosition2
 };
-
 @interface NSIndexPath
 @end