Use an autorelease pool on i386 instead

Author: aschwaighofer

stdlib/public/stubs/SwiftNativeNSXXXBaseARC.m

@@ -24,30 +24,46 @@
 // want ARC to insert 'objc_retainAutoreleasedReturnValue' and the necessary
 // markers for the hand-off.
 
+// On i386 we use an autorelease pool to prevent leaking.
+#if defined(__i386__)
+#define AUTORELEASEPOOL @autoreleasepool
+#else
+// On other platforms we rely on autorelease return optimization.
+#define AUTORELEASEPOOL
+#endif
+
 SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERFACE
 size_t swift_stdlib_NSStringHashValue(NSString *NS_RELEASES_ARGUMENT str,
                                       bool isASCII) {
-  return isASCII ? str.hash : str.decomposedStringWithCanonicalMapping.hash;
+  AUTORELEASEPOOL {
+    return isASCII ? str.hash : str.decomposedStringWithCanonicalMapping.hash;
+  }
 }
 
 SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERFACE
 size_t
 swift_stdlib_NSStringHashValuePointer(void *opaque, bool isASCII) {
   NSString __unsafe_unretained *str =
       (__bridge NSString __unsafe_unretained *)opaque;
-  return isASCII ? str.hash : str.decomposedStringWithCanonicalMapping.hash;
+  AUTORELEASEPOOL {
+    return isASCII ? str.hash : str.decomposedStringWithCanonicalMapping.hash;
+  }
 }
 
 SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERFACE
 NS_RETURNS_RETAINED NSString *
 swift_stdlib_NSStringLowercaseString(NSString *NS_RELEASES_ARGUMENT str) {
-  return str.lowercaseString;
+  AUTORELEASEPOOL {
+    return str.lowercaseString;
+  }
 }
 
 SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERFACE
 NS_RETURNS_RETAINED NSString *
 swift_stdlib_NSStringUppercaseString(NSString *NS_RELEASES_ARGUMENT str) {
-  return str.uppercaseString;
+  AUTORELEASEPOOL {
+    return str.uppercaseString;
+  }
 }
 
 #endif

test/stdlib/StringMemoryTest.swift

@@ -6,10 +6,6 @@
 // REQUIRES: executable_test
 // REQUIRES: objc_interop
 
-// The autorelease return optimizaion seems to be failing in the simulator.
-// rdar://34863458
-// XFAIL: CPU=i386
-
 import Foundation
 
 let str = "abcdefg\u{A758}hijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\u{A759}"