[ImmediateRef] Add failing tests.

test/test/spec/immediateref_spec.rb

@@ -0,0 +1,23 @@
+describe "ImmediateRef" do
+  class << self
+    # Tagged pointers are only available on 64-bit platforms.
+    alias_method :on_64bit_it, RUBY_ARCH =~ /64/ ? :it : :xit
+  end
+
+  on_64bit_it "forwards messages to the wrapped tagged pointer object" do
+    ref = TaggedNSObjectSubclass.taggedObject(42)
+    ref.class.should == TaggedNSObjectSubclass
+    ref.taggedValue.should == 42
+    ref.should == TaggedNSObjectSubclass.taggedObject(42)
+  end
+
+  on_64bit_it "returns the tagged pointer object's methods" do
+    ref = TaggedNSObjectSubclass.taggedObject(42)
+    ref.public_methods(false).should == [:taggedValue, :'isEqualTo:']
+  end
+
+  on_64bit_it "returns the tagged pointer object's description" do
+    ref = TaggedNSObjectSubclass.taggedObject(42)
+    ref.inspect.should.start_with '#<TaggedNSObjectSubclass'
+  end
+end

test/test/vendor/code/code.h

@@ -90,3 +90,11 @@ typedef int (^ReturnsIntBlock)();
 void KreateStackBlock(void (^inputBlock)(ReturnsIntBlock));
 ReturnsIntBlock KreateMallocBlock(int input);
 ReturnsIntBlock KreateGlobalBlock();
+
+#ifdef __LP64__
+@interface TaggedNSObjectSubclass : NSObject
++ (id)taggedObject:(uintptr_t)value;
+- (uintptr_t)taggedValue;
+- (BOOL)isEqualTo:(id)other;
+@end
+#endif

test/test/vendor/code/code.m

@@ -177,3 +177,33 @@ ReturnsIntBlock KreateGlobalBlock()
 {
   return ^{ return 42; };
 }
+
+#ifdef __LP64__
+void _objc_insert_tagged_isa(unsigned char slotNumber, Class isa);
+#define SLOT_NUMBER 7
+
+@implementation TaggedNSObjectSubclass
+
++ (void)load;
+{
+    _objc_insert_tagged_isa(SLOT_NUMBER, [TaggedNSObjectSubclass class]);
+}
+
++ (id)taggedObject:(uintptr_t)value;
+{
+    return (id)(1UL | ((uintptr_t)SLOT_NUMBER << 1) | (value << 4));
+}
+
+- (uintptr_t)taggedValue
+{
+    return (uintptr_t)self >> 4;
+}
+
+- (BOOL)isEqualTo:(id)other;
+{
+    return [other isKindOfClass:[TaggedNSObjectSubclass class]] &&
+	    [self taggedValue] == [other taggedValue];
+}
+
+@end
+#endif