aot compiler halts when there exists an infinite loop in clinit()

[Yuting Chen]

Besides,  if a class initializer writes into an external file (or make
some computations), the compiler will have side effects when compiling
the corresponding class, :).

On Tue, Apr 18, 2017 at 5:17 PM, Yuting Chen <chenyt.cs.sjtu at gmail.com> wrote:
> Thank you, Vladimir. Should it be better if the compiler can report a
> timeout error for such a class initializer?
>
> On Tue, Apr 18, 2017 at 4:46 PM, Vladimir Kozlov
> <vladimir.kozlov at oracle.com> wrote:
>> On 4/18/17 2:20 PM, Yuting Chen wrote:
>>>
>>> Hi, are there any comments to this case? I found that the clinit
>>> method will be compiled if it does not contain the infinite loop. Does
>>> it mean that clinit will run before it is compiled.
>>
>>
>> Yes, AOT compiler will run class initializer since it needs to access static
>> fields and other values.
>>
>> Vladimir
>>
>>
>>>
>>> Re-paste the bytecode:
>>>
>>> public class Vector1
>>>   minor version: 0
>>>   major version: 52
>>>   flags: ACC_PUBLIC, ACC_SUPER
>>> Constant pool:
>>>    #1 = Utf8               Vector1
>>>    #2 = Class              #1             // Vector1
>>>    #3 = Utf8               java/lang/Object
>>>    #4 = Class              #3             // java/lang/Object
>>>    #5 = Utf8               serialVersionUID
>>>    #6 = Utf8               J
>>>    #7 = Long               -2767605614048989439l
>>>    #9 = Utf8               <clinit>
>>>   #10 = Utf8               ()V
>>>   #11 = NameAndType        #5:#6          // serialVersionUID:J
>>>   #12 = Fieldref           #2.#11         // Vector1.serialVersionUID:J
>>>   #13 = Utf8               main
>>>   #14 = Utf8               ([Ljava/lang/String;)V
>>>   #15 = Utf8               ConstantValue
>>>   #16 = Utf8               Code
>>>   #17 = Utf8               StackMapTable
>>> {
>>>   public static {};
>>>     descriptor: ()V
>>>     flags: ACC_PUBLIC, ACC_STATIC
>>>     Code:
>>>       stack=2, locals=0, args_size=0
>>>          0: ldc2_w        #7                  // long
>>> -2767605614048989439l
>>>          3: putstatic     #12                 // Field serialVersionUID:J
>>>          6: iconst_1
>>>          7: iconst_m1
>>>          8: iadd
>>>          9: ifge          0
>>>         12: return
>>>       StackMapTable: number_of_entries = 1
>>>         frame_type = 0 /* same */
>>>
>>>   public static void main(java.lang.String[]);
>>>     descriptor: ([Ljava/lang/String;)V
>>>     flags: ACC_PUBLIC, ACC_STATIC
>>>     Code:
>>>       stack=0, locals=1, args_size=1
>>>          0: return
>>> }
>>>
>>> On Tue, Apr 18, 2017 at 9:41 AM, Yuting Chen <chenyt.cs.sjtu at gmail.com>
>>> wrote:
>>>>
>>>> Hi, are there any comments to this case? I found that the clinit
>>>> method will be compiled if it does not contain the infinite loop. It's
>>>> weird.
>>>>
>>>> The bytecode is shown as follows:
>>>>
>>>>  public class Vector1
>>>>    minor version: 0
>>>>    major version: 52
>>>>    flags: ACC_PUBLIC, ACC_SUPER
>>>>  Constant pool:
>>>>     #1 = Utf8               Vector1
>>>>     #2 = Class              #1             // Vector1
>>>>     #3 = Utf8               java/lang/Object
>>>>     #4 = Class              #3             // java/lang/Object
>>>>     #5 = Utf8               serialVersionUID
>>>>     #6 = Utf8               J
>>>>     #7 = Long               -2767605614048989439l
>>>>     #9 = Utf8               <clinit>
>>>>    #10 = Utf8               ()V
>>>>    #11 = NameAndType        #5:#6          // serialVersionUID:J
>>>>    #12 = Fieldref           #2.#11         // Vector1.serialVersionUID:J
>>>>    #13 = Utf8               main
>>>>    #14 = Utf8               ([Ljava/lang/String;)V
>>>>    #15 = Utf8               ConstantValue
>>>>    #16 = Utf8               Code
>>>>    #17 = Utf8               StackMapTable
>>>>  {
>>>>    public static {};
>>>>      descriptor: ()V
>>>>      flags: ACC_PUBLIC, ACC_STATIC
>>>>      Code:
>>>>        stack=2, locals=0, args_size=0
>>>>           0: ldc2_w        #7                  // long
>>>> -2767605614048989439l
>>>>           3: putstatic     #12                 // Field
>>>> serialVersionUID:J
>>>>           6: iconst_1
>>>>           7: iconst_m1
>>>>           8: iadd
>>>>           9: ifge          0
>>>>          12: return
>>>>        StackMapTable: number_of_entries = 1
>>>>          frame_type = 0 /* same */
>>>>
>>>>    public static void main(java.lang.String[]);
>>>>      descriptor: ([Ljava/lang/String;)V
>>>>      flags: ACC_PUBLIC, ACC_STATIC
>>>>      Code:
>>>>        stack=0, locals=1, args_size=1
>>>>           0: return
>>>>  }