experiences with prototype
Peter Levart
peter.levart at gmail.com
Wed Feb 4 08:46:21 UTC 2015
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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