Clang importer: teach importFullName about dropping certain variadics.

This moves the hack used for UIActionSheet and UIAlertView's variadic
designated initializers over into importFullName().

Author: DougGregor

lib/ClangImporter/ClangImporter.cpp

@@ -1594,6 +1594,46 @@ StringRef ClangImporter::Implementation::getEnumConstantNamePrefix(
   return commonPrefix;
 }
 
+/// Determine whether the given Clang selector matches the given
+/// selector pieces.
+static bool isNonNullarySelector(clang::Selector selector,
+                                 ArrayRef<StringRef> pieces) {
+  unsigned n = selector.getNumArgs();
+  if (n == 0) return false;
+  if (n != pieces.size()) return false;
+
+  for (unsigned i = 0; i != n; ++i) {
+    if (selector.getNameForSlot(i) != pieces[i]) return false;
+  }
+
+  return true;
+}
+
+/// Whether we should make a variadic method with the given selector
+/// non-variadic.
+static bool shouldMakeSelectorNonVariadic(clang::Selector selector) {
+  // This is UIActionSheet's designated initializer.
+  if (isNonNullarySelector(selector,
+                           { "initWithTitle",
+                             "delegate",
+                             "cancelButtonTitle",
+                             "destructiveButtonTitle",
+                             "otherButtonTitles" }))
+    return true;
+
+  // This is UIAlertView's designated initializer.
+  if (isNonNullarySelector(selector,
+                           { "initWithTitle",
+                             "message",
+                             "delegate",
+                             "cancelButtonTitle",
+                             "otherButtonTitles" }))
+    return true;
+
+  // Nothing else for now.
+  return false;
+}
+
 auto ClangImporter::Implementation::importFullName(
        const clang::NamedDecl *D,
        clang::DeclContext **effectiveContext) -> ImportedName {
@@ -1694,8 +1734,16 @@ auto ClangImporter::Implementation::importFullName(
       baseName = "init";
     else
       baseName = selector.getNameForSlot(0);
-    for (unsigned index = 0, numArgs = selector.getNumArgs(); index != numArgs;
-         ++index) {
+
+    // If we have a variadic method for which we need to drop the last
+    // selector piece, do so now.
+    unsigned numArgs = selector.getNumArgs();
+    if (objcMethod->isVariadic() && shouldMakeSelectorNonVariadic(selector)) {
+      --numArgs;
+      result.DroppedVariadic = true;
+    }
+
+    for (unsigned index = 0; index != numArgs; ++index) {
       if (index == 0) {
         argumentNames.push_back(StringRef());
       } else {

lib/ClangImporter/ImporterImpl.h

@@ -753,6 +753,11 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
     /// swift_name attribute.
     bool HasCustomName = false;
 
+    /// Whether this was one of a special class of Objective-C
+    /// initializers for which we drop the variadic argument rather
+    /// than refuse to import the initializer.
+    bool DroppedVariadic = false;
+
     /// For an initializer, the kind of initializer to import.
     CtorInitializerKind InitKind;
 

test/IDE/Inputs/swift_name_objc.h

@@ -49,3 +49,7 @@ SWIFT_NAME(SomeProtocol)
 @protocol NSAccessibility
 @property (nonatomic) float accessibilityFloat;
 @end
+
+@interface UIActionSheet : NSObject
+-(instancetype)initWithTitle:(const char *)title delegate:(id)delegate cancelButtonTitle:(const char *)cancelButtonTitle destructiveButtonTitle:(const char *)destructiveButtonTitle otherButtonTitles:(const char *)otherButtonTitles, ...;
+@end

test/IDE/dump_swift_lookup_tables_objc.swift

@@ -9,12 +9,13 @@
 // CHECK-NEXT:   SNCollisionProtocol --> SNCollisionProtocol
 // CHECK-NEXT:   SomeClass --> SomeClass
 // CHECK-NEXT:   SomeProtocol --> SomeProtocol
+// CHECK-NEXT:   UIActionSheet --> UIActionSheet
 // CHECK-NEXT:   accessibilityFloat --> accessibilityFloat()
 // CHECK-NEXT:   categoryMethodWithX --> categoryMethodWithX(_:y:), categoryMethodWithX(_:y:z:)
 // CHECK-NEXT:   doubleProperty --> doubleProperty{{$}}
 // CHECK-NEXT:   extensionMethodWithX --> extensionMethodWithX(_:y:)
 // CHECK-NEXT:   floatProperty --> floatProperty{{$}}
-// CHECK-NEXT:   init --> init(float:), init(withDefault:), init(double:), init(withTry:), init(uint8:){{$}}
+// CHECK-NEXT:   init --> init(float:), init(withDefault:), init(double:), init(withTry:), init(uint8:), init(title:delegate:cancelButtonTitle:destructiveButtonTitle:)
 // CHECK-NEXT:   instanceMethodWithX --> instanceMethodWithX(_:y:z:)
 // CHECK-NEXT:   protoInstanceMethodWithX --> protoInstanceMethodWithX(_:y:)
 // CHECK-NEXT:   setAccessibilityFloat --> setAccessibilityFloat(_:)
@@ -30,6 +31,8 @@
 // CHECK-NEXT:     TU: SNSomeClass
 // CHECK-NEXT:   SomeProtocol:
 // CHECK-NEXT:     TU: SNSomeProtocol
+// CHECK-NEXT:   UIActionSheet:
+// CHECK-NEXT:     TU: UIActionSheet
 // CHECK-NEXT:   accessibilityFloat():
 // CHECK-NEXT:     NSAccessibility: -[NSAccessibility accessibilityFloat]
 // CHECK-NEXT:   categoryMethodWithX(_:y:):
@@ -46,6 +49,8 @@
 // CHECK-NEXT:     SNSomeClass: +[SNSomeClass someClassWithDouble:]
 // CHECK-NEXT:   init(float:):
 // CHECK-NEXT:     SNSomeClass: -[SNSomeClass initWithFloat:]
+// CHECK-NEXT:   init(title:delegate:cancelButtonTitle:destructiveButtonTitle:):
+// CHECK-NEXT:     UIActionSheet: -[UIActionSheet initWithTitle:delegate:cancelButtonTitle:destructiveButtonTitle:otherButtonTitles:]
 // CHECK-NEXT:   init(uint8:):
 // CHECK-NEXT:     SNSomeClass: +[SNSomeClass buildWithUnsignedChar:]
 // CHECK-NEXT:   init(withDefault:):