experiences with prototype

Maurizio Cimadamore maurizio.cimadamore at oracle.com
Wed Feb 4 12:42:42 UTC 2015


Compiler fixes have been pushed, I will now look into the runtime issues 
you are getting...

Maurizio

On 04/02/15 10:18, Maurizio Cimadamore wrote:
> Thanks for the additional feedback, I'll try to get at the bottom of 
> those issues.
>
> Maurizio
>
> On 04/02/15 08:46, Peter Levart wrote:
>> Hi Maurizio,
>>
>> I have now managed to successfully compile the code. Here's the 
>> updated source:
>>
>> http://cr.openjdk.java.net/~plevart/misc/valhala-hacks/javany-src.jar
>>
>>
>> But there's a StringIndexOutOfBoundsException thrown from specializer 
>> when running the following Test:
>>
>> public class Test {
>>     public static void main(String[] args) {
>>         List<int> ints = Arrays.asList(new int[]{1, 2, 3, 4, 5, 6, 7, 
>> 8});
>>         Iterator<int> it = ints.iterator();
>>         while (it.hasNext()) {
>>             System.out.println(it.next());
>>         }
>>     }
>> }
>>
>>
>> Specializing javany.util.List${0=I}; searching for 
>> javany/util/List.class (not found)
>> Specializing javany.util.List${0=I}; searching for 
>> javany/util/List.class (found)
>> Specializing javany.util.Collection${0=I}; searching for 
>> javany/util/Collection.class (not found)
>> Specializing javany.util.Collection${0=I}; searching for 
>> javany/util/Collection.class (found)
>> Specializing javany.lang.Iterable${0=I}; searching for 
>> javany/lang/Iterable.class (not found)
>> Specializing javany.lang.Iterable${0=I}; searching for 
>> javany/lang/Iterable.class (found)
>> Specializing method 
>> javany/util/Arrays$asList${0=I}.asList([Ljava/lang/Object;)Ljavany/util/List; 
>> with class=[] and method=[I]
>> Specializing javany.util.Arrays$ArrayList${0=I}; searching for 
>> javany/util/Arrays$ArrayList.class (not found)
>> Specializing javany.util.Arrays$ArrayList${0=I}; searching for 
>> javany/util/Arrays$ArrayList.class (found)
>> Exception in thread "main" java.lang.StringIndexOutOfBoundsException: 
>> String index out of range: 0
>>         at java.lang.String.charAt(String.java:646)
>>         at 
>> jdk.internal.org.objectweb.asm.signature.SignatureReader.accept(SignatureReader.java:107)
>>         at 
>> valhalla.specializer.SignatureSpecializer.forType(SignatureSpecializer.java:72)
>>         at 
>> valhalla.specializer.Specializer$ManglingMethodVisitor.visitInvokeDynamicInsn(Specializer.java:679)
>>         at 
>> jdk.internal.org.objectweb.asm.ClassReader.readCode(ClassReader.java:1507)
>>         at 
>> jdk.internal.org.objectweb.asm.ClassReader.readMethod(ClassReader.java:1084)
>>         at 
>> jdk.internal.org.objectweb.asm.ClassReader.accept(ClassReader.java:729)
>>         at 
>> valhalla.specializer.Specializer.specialize(Specializer.java:79)
>>         at java.net.URLClassLoader$1.run(URLClassLoader.java:409)
>>         at java.net.URLClassLoader$1.run(URLClassLoader.java:386)
>>         at java.security.AccessController.doPrivileged(Native Method)
>>         at java.net.URLClassLoader.findClass(URLClassLoader.java:385)
>>         at java.lang.ClassLoader.loadClass(ClassLoader.java:426)
>>         at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:317)
>>         at java.lang.ClassLoader.loadClass(ClassLoader.java:359)
>>         at 
>> javany.util.Arrays$asList${0=I}/511754216.asList(Arrays.java:810)
>>         at Test.main(Test.java:10)
>>
>>
>> Appart from that, I learned that when the component type of vararg 
>> array is an <any> type variable (for example: <any T> T[] 
>> Arrays.asList(T ... a)), the invocation doesn't compile:
>>
>> src/Test.java:10: error: method invoked with incorrect number of 
>> arguments; expected 3, found 1
>>         List<int> ints = Arrays.<int>asList(1, 2, 3);
>>                          ^
>> 1 error
>>
>>
>> Non-specialized code also has problems at runtime:
>>
>> public class Test {
>>     public static void main(String[] args) {
>>         List<String> strings = Arrays.<String>asList("a", "b", "c");
>>         Iterator<String> it = strings.iterator();
>>         while (it.hasNext()) {
>>             System.out.println(it.next());
>>         }
>>     }
>> }
>>
>>
>> Exception in thread "main" java.lang.ClassFormatError: Absent Code 
>> attribute in method that is not native or abstract in class file 
>> javany/util/AbstractList
>>         at java.lang.ClassLoader.defineClass1(Native Method)
>>         at java.lang.ClassLoader.defineClass(ClassLoader.java:762)
>>         at 
>> java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
>>         at java.net.URLClassLoader.defineClass(URLClassLoader.java:537)
>>         at java.net.URLClassLoader.access$300(URLClassLoader.java:78)
>>         at java.net.URLClassLoader$1.run(URLClassLoader.java:438)
>>         at java.net.URLClassLoader$1.run(URLClassLoader.java:386)
>>         at java.security.AccessController.doPrivileged(Native Method)
>>         at java.net.URLClassLoader.findClass(URLClassLoader.java:385)
>>         at java.lang.ClassLoader.loadClass(ClassLoader.java:426)
>>         at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:317)
>>         at java.lang.ClassLoader.loadClass(ClassLoader.java:359)
>>         at java.lang.ClassLoader.defineClass1(Native Method)
>>         at java.lang.ClassLoader.defineClass(ClassLoader.java:762)
>>         at 
>> java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
>>         at java.net.URLClassLoader.defineClass(URLClassLoader.java:537)
>>         at java.net.URLClassLoader.access$300(URLClassLoader.java:78)
>>         at java.net.URLClassLoader$1.run(URLClassLoader.java:438)
>>         at java.net.URLClassLoader$1.run(URLClassLoader.java:386)
>>         at java.security.AccessController.doPrivileged(Native Method)
>>         at java.net.URLClassLoader.findClass(URLClassLoader.java:385)
>>         at java.lang.ClassLoader.loadClass(ClassLoader.java:426)
>>         at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:317)
>>         at java.lang.ClassLoader.loadClass(ClassLoader.java:359)
>>         at javany.util.Arrays.asList(Arrays.java:810)
>>         at Test.main(Test.java:10)
>>
>>
>>
>> Regards, Peter
>>
>> On 02/03/2015 10:34 PM, Maurizio Cimadamore wrote:
>>>
>>> On 03/02/15 21:05, Peter Levart wrote:
>>>> Hi Maurizio,
>>>>
>>>> I see. I thought this could be a nice idiom for boxing, since the 
>>>> following:
>>>>
>>>> (Object) 42
>>>>
>>>> ...is legal and results in an Integer object at runtime.
>>> I'm not saying this will never work - actually the compiler is 
>>> currently accepting this kind of idioms, but the specializer does 
>>> nothing with it, so you'll get runtime errors.
>>>>
>>>> But I don't know if a checkcast is actually inserted for (Object). 
>>>> Could javac redundantly do it in case casting to Object is from 
>>>> expression of <any> type and also equip checkcast with BMA 
>>>> indicating the type of expression so that specialization could 
>>>> replace it with boxing code?
>>> That will be the way forward, yes
>>>
>>> Maurizio
>>>>
>>>> Regards, Peter
>>>>
>>>>
>>>> On 02/03/2015 08:09 PM, Maurizio Cimadamore wrote:
>>>>>
>>>>> On 03/02/15 18:46, Maurizio Cimadamore wrote:
>>>>>> I will also investigate on the crash you are getting... 
>>>>> Hi Peter,
>>>>> the crash is coming from this code in AbstractCollection (see code 
>>>>> in bold):
>>>>>
>>>>>     public boolean contains(Object o) {
>>>>>         __WhereVal(E) {
>>>>>             Iterator<E> it = iterator();
>>>>>             if (o == null) {
>>>>>                 return false;
>>>>>             } else {
>>>>>                 while (it.hasNext())
>>>>> *if (o.equals((Object) it.next()))*
>>>>>                         return true;
>>>>>             }
>>>>>             return false;
>>>>>         }
>>>>>         __WhereRef(E) {
>>>>>             Iterator<E> it = iterator();
>>>>>             if (o == null) {
>>>>>                 while (it.hasNext())
>>>>>                     if (it.next() == null)
>>>>>                         return true;
>>>>>             } else {
>>>>>                 while (it.hasNext())
>>>>>                     if (o.equals(it.next()))
>>>>>                         return true;
>>>>>             }
>>>>>             return false;
>>>>>         }
>>>>>     }
>>>>>
>>>>> I believe that, apart from the obvious javac bug, the code has an 
>>>>> issue, as it.next() is supposed to return a value there, but you 
>>>>> are casting to Object?
>>>>>
>>>>> For the records - a simpler test case for the bug is this:
>>>>>
>>>>> class Foo<any E> {
>>>>>     E e;
>>>>>     E get() { return e; }
>>>>>
>>>>>     void test() {
>>>>>         __WhereVal(E) {
>>>>>             Object o = (Object)get();
>>>>>         }
>>>>>     }
>>>>> }
>>>>>
>>>>> Maurizio
>>>>
>>>
>>>
>>
>



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