[PrintAsObjC] Use C names when printing imported structs.

(and enums)

Previously this part of the compiler assumed that any imported
struct or enum would have the same name as it does in C, which is
no longer true.

Part of rdar://problem/26372925

Author: jrose-apple

lib/PrintAsObjC/PrintAsObjC.cpp

@@ -73,18 +73,25 @@ namespace {
   };
 }
 
-static Identifier getNameForObjC(const ValueDecl *VD,
-                                 CustomNamesOnly_t customNamesOnly = Normal) {
-  assert(isa<ClassDecl>(VD) || isa<ProtocolDecl>(VD)
-      || isa<EnumDecl>(VD) || isa<EnumElementDecl>(VD));
+static StringRef getNameForObjC(const ValueDecl *VD,
+                                CustomNamesOnly_t customNamesOnly = Normal) {
+  assert(isa<ClassDecl>(VD) || isa<ProtocolDecl>(VD) || isa<StructDecl>(VD) ||
+         isa<EnumDecl>(VD) || isa<EnumElementDecl>(VD));
   if (auto objc = VD->getAttrs().getAttribute<ObjCAttr>()) {
     if (auto name = objc->getName()) {
       assert(name->getNumSelectorPieces() == 1);
-      return name->getSelectorPieces().front();
+      return name->getSelectorPieces().front().str();
     }
   }
 
-  return customNamesOnly ? Identifier() : VD->getName();
+  if (customNamesOnly)
+    return StringRef();
+
+  if (auto clangDecl = dyn_cast_or_null<clang::NamedDecl>(VD->getClangDecl()))
+    if (const clang::IdentifierInfo *II = clangDecl->getIdentifier())
+      return II->getName();
+
+  return VD->getName().str();
 }
 
 
@@ -187,7 +194,7 @@ class ObjCPrinter : private DeclVisitor<ObjCPrinter>,
   void visitClassDecl(ClassDecl *CD) {
     printDocumentationComment(CD);
 
-    Identifier customName = getNameForObjC(CD, CustomNamesOnly);
+    StringRef customName = getNameForObjC(CD, CustomNamesOnly);
     if (customName.empty()) {
       llvm::SmallString<32> scratch;
       os << "SWIFT_CLASS(\"" << CD->getObjCRuntimeName(scratch) << "\")\n"
@@ -219,7 +226,7 @@ class ObjCPrinter : private DeclVisitor<ObjCPrinter>,
   void visitProtocolDecl(ProtocolDecl *PD) {
     printDocumentationComment(PD);
 
-    Identifier customName = getNameForObjC(PD, CustomNamesOnly);
+    StringRef customName = getNameForObjC(PD, CustomNamesOnly);
     if (customName.empty()) {
       llvm::SmallString<32> scratch;
       os << "SWIFT_PROTOCOL(\"" << PD->getObjCRuntimeName(scratch) << "\")\n"
@@ -240,7 +247,7 @@ class ObjCPrinter : private DeclVisitor<ObjCPrinter>,
   void visitEnumDecl(EnumDecl *ED) {
     printDocumentationComment(ED);
     os << "typedef ";
-    Identifier customName = getNameForObjC(ED, CustomNamesOnly);
+    StringRef customName = getNameForObjC(ED, CustomNamesOnly);
     if (customName.empty()) {
       os << "SWIFT_ENUM(";
     } else {
@@ -260,7 +267,7 @@ class ObjCPrinter : private DeclVisitor<ObjCPrinter>,
       // Print the cases as the concatenation of the enum name with the case
       // name.
       os << "  ";
-      Identifier customEltName = getNameForObjC(Elt, CustomNamesOnly);
+      StringRef customEltName = getNameForObjC(Elt, CustomNamesOnly);
       if (customEltName.empty()) {
         if (customName.empty()) {
           os << ED->getName();
@@ -1014,7 +1021,7 @@ class ObjCPrinter : private DeclVisitor<ObjCPrinter>,
       return;
 
     maybePrintTagKeyword(SD);
-    os << SD->getName();
+    os << getNameForObjC(SD);
   }
 
   /// Print a collection element type using Objective-C generics syntax.

test/PrintAsObjC/Inputs/swift_name.h

@@ -0,0 +1,22 @@
+// This file is meant to be used with the mock SDK, not the real one.
+#import <Foundation.h>
+
+#define SWIFT_NAME(x) __attribute__((swift_name(#x)))
+
+typedef NSString *ABCStringAlias SWIFT_NAME(ZZStringAlias);
+struct ABCPoint {
+  int x;
+  int y;
+} SWIFT_NAME(ZZPoint);
+enum ABCAlignment {
+  ABCAlignmentLeft,
+  ABCAlignmentRight
+} SWIFT_NAME(ZZAlignment);
+
+SWIFT_NAME(ZZClass)
+@interface ABCClass : NSObject
+@end
+
+SWIFT_NAME(ZZProto)
+@protocol ABCProto
+@end

test/PrintAsObjC/swift_name.swift

@@ -0,0 +1,33 @@
+// Please keep this file in alphabetical order!
+
+// REQUIRES: objc_interop
+
+// RUN: rm -rf %t && mkdir %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) -import-objc-header %S/Inputs/swift_name.h -emit-module -o %t %s
+// RUN: %target-swift-frontend(mock-sdk: -sdk %S/../Inputs/clang-importer-sdk -I %t) -import-objc-header %S/Inputs/swift_name.h -parse-as-library %t/swift_name.swiftmodule -parse -emit-objc-header-path %t/swift_name.h
+
+// RUN: FileCheck %s < %t/swift_name.h
+// RUN: %check-in-clang %t/swift_name.h
+
+import Foundation
+
+// CHECK-LABEL: @interface Test : NSObject
+// CHECK-NEXT: - (NSArray<ABCStringAlias> * _Nonnull)makeArray:(ABCStringAlias _Nonnull)_;
+// CHECK-NEXT: - (void)usePoint:(struct ABCPoint)_;
+// CHECK-NEXT: - (void)useAlignment:(enum ABCAlignment)_;
+// CHECK-NEXT: - (NSArray<id <ABCProto>> * _Nonnull)useObjects:(ABCClass * _Nonnull)_;
+// CHECK-NEXT: - (nonnull instancetype)init OBJC_DESIGNATED_INITIALIZER;
+// CHECK-NEXT: @end
+class Test : NSObject {
+  func makeArray(_: ZZStringAlias) -> [ZZStringAlias] { return [] }
+  func usePoint(_: ZZPoint) {}
+  func useAlignment(_: ZZAlignment) {}
+  func useObjects(_: ZZClass) -> [ZZProto] { return [] }
+}