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Greg Parker
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[runtime] Add tests of pre-stable ABI objects with the stable ABI runtime (#21403)
 * [test] Fix objc_old_swift when objc/objc-internal.h is not in the SDK.
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‎test/Interpreter/SDK/Inputs/OldABI/OldABI.h

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#include <objc/objc.h>
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OBJC_EXTERN bool CanTestOldABI();
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OBJC_EXTERN id _Nonnull AllocOldABIObject();

‎test/Interpreter/SDK/Inputs/OldABI/OldABI.mm

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#include "OldABI.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <limits.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <malloc/malloc.h>
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#include <objc/runtime.h>
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#include <Foundation/Foundation.h>
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// Implementation of ObjC classes
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// with bits set to mimic the pre-stable Swift ABI
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// and additional memory protection to detect mis-use
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#if __has_include(<objc/objc-internal.h>)
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#include <objc/objc-internal.h>
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#else
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extern "C" Class objc_initializeClassPair(Class superclass, const char *name, Class cls, Class metacls);
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extern "C" id _objc_rootRetain(id);
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extern "C" void _objc_rootRelease(id);
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extern "C" id _objc_rootAutorelease(id);
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extern "C" uintptr_t _objc_rootRetainCount(id);
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extern "C" bool _objc_rootTryRetain(id);
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extern "C" bool _objc_rootIsDeallocating(id);
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#endif
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// This class stands in for the pre-stable ABI's SwiftObject.
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// Stable Swift's class is named Swift._SwiftObject (but mangled).
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__attribute__((objc_root_class))
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@interface SwiftObject { id isa; } @end
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@implementation SwiftObject
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+(void)initialize { }
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+(id)allocWithZone:(struct _malloc_zone_t *)zone {
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return class_createInstance(self, 0);
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}
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+(id)alloc { return [self allocWithZone:nil]; }
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+(id)class { return self; }
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-(id)class { return object_getClass(self); }
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+(id)superclass { return class_getSuperclass(self); }
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-(id)superclass { return class_getSuperclass([self class]); }
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+(BOOL)isMemberOfClass:(Class)cls { return object_getClass(self) == cls; }
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-(BOOL)isMemberOfClass:(Class)cls { return [self class] == cls; }
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-(id)self { return self; }
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-(BOOL)isProxy { return NO; }
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-(struct _malloc_zone_t *)zone { return malloc_default_zone(); }
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-(void)doesNotRecognizeSelector:(SEL)sel {
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Class cls = [self class];
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fprintf(stderr, "unrecognized selector %c[%s %s]\n",
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class_isMetaClass(cls) ? '+' : '-',
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class_getName(cls), sel_getName(sel));
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abort();
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}
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+(id)retain { return self; }
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+(void)release { }
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+(id)autorelease { return self; }
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+(uintptr_t)retainCount { return ~(uintptr_t)0; }
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+(BOOL)_tryRetain { return YES; }
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+(BOOL)_isDeallocating { return NO; }
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-(id)retain { return _objc_rootRetain(self); }
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-(void)release { _objc_rootRelease(self); }
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-(id)autorelease { return _objc_rootAutorelease(self); }
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-(uintptr_t)retainCount { return _objc_rootRetainCount(self); }
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-(BOOL)_tryRetain { return _objc_rootTryRetain(self); }
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-(BOOL)_isDeallocating { return _objc_rootIsDeallocating(self); }
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-(void)dealloc { object_dispose(self); }
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-(BOOL)isKindOfClass:(Class)other {
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for (Class cls = object_getClass(self); cls; cls = class_getSuperclass(cls))
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if (cls == other) return YES;
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return NO;
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}
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+(BOOL)isSubclassOfClass:(Class)other {
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for (Class cls = self; cls; cls = class_getSuperclass(cls))
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if (cls == other) return YES;
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return NO;
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}
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-(BOOL)respondsToSelector:(SEL)sel {
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if (!sel) return NO;
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return class_respondsToSelector(object_getClass(self), sel);
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}
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+(BOOL)instancesRespondToSelector:(SEL)sel {
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if (!sel) return NO;
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return class_respondsToSelector(self, sel);
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}
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-(uintptr_t)hash { return (uintptr_t)self; }
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-(BOOL)isEqual:(id)other { return self == other; }
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+(NSString *)description { return @"FakeSwiftObject class"; }
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-(NSString *)description { return @"FakeSwiftObject instance"; }
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-(NSString *)debugDescription { return [self description]; }
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- (BOOL)isNSArray__ { return NO; }
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- (BOOL)isNSCFConstantString__ { return NO; }
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- (BOOL)isNSData__ { return NO; }
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- (BOOL)isNSDate__ { return NO; }
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- (BOOL)isNSDictionary__ { return NO; }
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- (BOOL)isNSObject__ { return NO; }
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- (BOOL)isNSOrderedSet__ { return NO; }
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- (BOOL)isNSNumber__ { return NO; }
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- (BOOL)isNSSet__ { return NO; }
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- (BOOL)isNSString__ { return NO; }
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- (BOOL)isNSTimeZone__ { return NO; }
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- (BOOL)isNSValue__ { return NO; }
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@end
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static char *AllocTailGuardedPointer(size_t size) {
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// Round up to page boundary.
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size_t writeableSize = (size + PAGE_MAX_SIZE - 1) & ~(PAGE_MAX_SIZE - 1);
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// Allocate writeable memory plus one guard page.
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char *writeableBuffer = (char *)mmap(0, writeableSize + PAGE_MAX_SIZE,
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PROT_READ | PROT_WRITE,
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MAP_ANON | MAP_PRIVATE, -1, 0);
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if (writeableBuffer == MAP_FAILED) abort();
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// Mark the guard page inaccessible.
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mprotect(writeableBuffer + writeableSize, PAGE_MAX_SIZE, 0);
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// Scribble on the prefix.
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memset(writeableBuffer, 0x55, writeableSize - size);
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// Return the address just before the guard page.
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// FIXME: this doesn't handle alignment properly,
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// but we don't need to for this test's usage.
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return writeableBuffer + writeableSize - size;
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}
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static Class CreateOldABISubclass(Class supercls, const char *name) {
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// Allocate class and metaclass in tail-guarded memory.
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// If the Swift runtime incorrectly tries to read Swift
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// metadata from this class then it'll crash.
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char *clsbuf = AllocTailGuardedPointer(5*sizeof(uintptr_t));
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char *metabuf = AllocTailGuardedPointer(5*sizeof(uintptr_t));
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Class result = objc_initializeClassPair(supercls, name,
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(Class)clsbuf, (Class)metabuf);
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// Set the old is-Swift bit in the class.
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uintptr_t *words = (uintptr_t *)clsbuf;
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words[4] |= 1;
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return result;
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}
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static Class FakeOldABIClass;
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__attribute__((constructor))
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static void initialize(void) {
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FakeOldABIClass = CreateOldABISubclass([SwiftObject class],
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"_TtC6OldABI8Subclass");
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}
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bool CanTestOldABI() {
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// These tests don't work until the stable ABI is using its designed bit.
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// This check can be removed after SWIFT_DARWIN_ENABLE_STABLE_ABI_BIT
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// is set everywhere.
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Class cls = objc_getClass("_TtCs19__EmptyArrayStorage");
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if (!cls) abort();
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uintptr_t *words = (uintptr_t *)cls;
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if ((words[4] & 3) != 2) return false; // wrong stable is-Swift bit
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return true;
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}
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id AllocOldABIObject() {
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return [FakeOldABIClass alloc];
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}

‎test/Interpreter/SDK/Inputs/OldABI/module.map

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module OldABI {
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header "OldABI.h"
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}

‎test/Interpreter/SDK/objc_old_swift.swift

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// RUN: %empty-directory(%t)
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//
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// RUN: cp %s %t/main.swift
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// RUN: %target-clang %S/Inputs/OldABI/OldABI.mm -g -c -o %t/OldABI.o
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// RUN: %target-build-swift %t/main.swift -framework Foundation -I %S/Inputs/OldABI/ -Xlinker %t/OldABI.o -o %t/objc_old_swift -Xfrontend -disable-access-control
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// RUN: %target-codesign %t/objc_old_swift
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// RUN: %target-run %t/objc_old_swift
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// REQUIRES: executable_test
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// REQUIRES: objc_interop
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// Verify that objects that appear to be from the pre-stable Swift ABI
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// are correctly ignored by stable Swift's entry points.
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import Foundation
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import OldABI
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import StdlibUnittest
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var tests = TestSuite("objc_old_swift")
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tests.test("description")
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.skip(.custom({ !CanTestOldABI() },
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reason: "not using stable ABI's is-Swift bit yet"))
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.code {
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let obj = AllocOldABIObject()
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expectEqual(String(describing:obj), "OldABI.Subclass")
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expectEqual((obj as AnyObject).description!, "FakeSwiftObject instance")
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}
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tests.test("casts")
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.skip(.custom({ !CanTestOldABI() },
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reason: "not using stable ABI's is-Swift bit yet"))
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.code {
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let obj = AllocOldABIObject()
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expectNil(obj as? String)
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expectNotNil(obj as Any)
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expectNotNil(obj as AnyObject)
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}
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tests.test("array")
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.skip(.custom({ !CanTestOldABI() },
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reason: "not using stable ABI's is-Swift bit yet"))
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.code {
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let array = Array(repeating: AllocOldABIObject(), count:5)
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expectEqual(String(describing: array), "[OldABI.Subclass, OldABI.Subclass, OldABI.Subclass, OldABI.Subclass, OldABI.Subclass]")
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var array2 = Array(repeating: AllocOldABIObject(), count:0)
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for i in 0..<array.count {
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expectNotNil(array[i])
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array2.append(i as NSNumber)
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array2.append(array[i]);
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}
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expectEqual(String(describing: array2), "[0, OldABI.Subclass, 1, OldABI.Subclass, 2, OldABI.Subclass, 3, OldABI.Subclass, 4, OldABI.Subclass]")
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// Bridge an array of pre-stable objects to NSArray
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let nsarray = NSMutableArray(array: array2)
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expectEqual(nsarray.description, #"""
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(
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0,
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"FakeSwiftObject instance",
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1,
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"FakeSwiftObject instance",
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2,
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"FakeSwiftObject instance",
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3,
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"FakeSwiftObject instance",
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4,
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"FakeSwiftObject instance"
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)
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"""#)
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nsarray.add(5 as NSNumber)
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// Bridge back from NSArray
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let array3 = nsarray as [AnyObject]
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expectEqual(String(describing: array3), "[0, OldABI.Subclass, 1, OldABI.Subclass, 2, OldABI.Subclass, 3, OldABI.Subclass, 4, OldABI.Subclass, 5]")
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}
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// FIXME: add coverage of more Swift runtime entrypoints
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runAllTests()

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