RFR: 8295893: Improve printing of Constant Pool Cache Entries [v8]

[Ioi Lam]

On Wed, 2 Nov 2022 16:55:50 GMT, Matias Saavedra Silva <matsaave at openjdk.org> wrote:

>> As an extension of [JDK-8292699](https://bugs.openjdk.org/browse/JDK-8292699), this aims to further improve the printing of Constant Pool Cache entries. The contents and flag are decoded into human readable text with an appendix printed as before.
>> 
>> The text format and contents are tentative, please review.
>> 
>> Here is an example output when using `findmethod()`:
>> 
>> "Executing findmethod"
>> flags (bitmask):
>>    0x01  - print names of methods
>>    0x02  - print bytecodes
>>    0x04  - print the address of bytecodes
>>    0x08  - print info for invokedynamic
>>    0x10  - print info for invokehandle
>> 
>> [  0] 0x0000000801000800 class Concat0 loader data: 0x00007ffff02ddeb0 for instance a 'jdk/internal/loader/ClassLoaders$AppClassLoader'{0x00000007fef59110}
>> 0x00007fffa0400368 static method main : ([Ljava/lang/String;)V
>>    0 iconst_0
>>    1 istore_1
>>    2 iload_1
>>    3 iconst_2
>>    4 if_icmpge 24
>>    7 getstatic 7 <Concat0.s/Ljava/lang/String;> 
>>   10 invokedynamic bsm=31 13 <makeConcatWithConstants(Ljava/lang/String;)Ljava/lang/String;>
>>   BSM: REF_invokeStatic 32 <java/lang/invoke/StringConcatFactory.makeConcatWithConstants(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/String;[Ljava/lang/Object;)Ljava/lang/invoke/CallSite;> 
>>   arguments[1] = {
>>      000
>>   }
>>   ConstantPoolCacheEntry:   4
>>  - this: 0x00007fffa0400570
>>  - bytecode 1: invokedynamic ba
>>  - bytecode 2: nop 00
>>  - cp index:    13
>>  - F1:  [   0x00000008000c8658]
>>  - F2:  [   0x0000000000000003]
>>  -     Method: 0x00000008000c8658 java.lang.Object java.lang.invoke.Invokers$Holder.linkToTargetMethod(java.lang.Object, java.lang.Object)
>>  - flag values: [08|0|0|1|1|0|1|0|0|0|00|00|02]
>>  - tos: object
>>  - local signature: 1
>>  - has appendix: 1
>>  - forced virtual: 0
>>  - final: 1
>>  - virtual Final: 0
>>  - resolution Failed: 0
>>  - num Parameters: 02
>>   Method: 0x00000008000c8658 java/lang/invoke/Invokers$Holder.linkToTargetMethod(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
>>   appendix: java.lang.invoke.BoundMethodHandle$Species_LL 
>> {0x000000011f021360} - klass: 'java/lang/invoke/BoundMethodHandle$Species_LL'
>>  - ---- fields (total size 5 words):
>>  - private 'customizationCount' 'B' @12  0 (0x00)
>>  - private volatile 'updateInProgress' 'Z' @13  false (0x00)
>>  - private final 'type' 'Ljava/lang/invoke/MethodType;' @16  a 'java/lang/invoke/MethodType'{0x000000011f0185b0} = (Ljava/lang/String;)Ljava/lang/String; (0x23e030b6)
>>  - final 'form' 'Ljava/lang/invoke/LambdaForm;' @20  a 'java/lang/invoke/LambdaForm'{0x000000011f01df40} => a 'java/lang/invoke/MemberName'{0x000000011f0211e8} = {method} {0x00007fffa04012a8} 'invoke' '(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;' in 'java/lang/invoke/LambdaForm$MH+0x0000000801000400' (0x23e03be8)
>>  - private 'asTypeCache' 'Ljava/lang/invoke/MethodHandle;' @24  NULL (0x00000000)
>>  - private 'asTypeSoftCache' 'Ljava/lang/ref/SoftReference;' @28  NULL (0x00000000)
>>  - final 'argL0' 'Ljava/lang/Object;' @32  a 'java/lang/invoke/DirectMethodHandle'{0x000000011f019b70} (0x23e0336e)
>>  - final 'argL1' 'Ljava/lang/Object;' @36  "000"{0x000000011f0193d0} (0x23e0327a)
>>                  -------------
>>   15 putstatic 17 <Concat0.d/Ljava/lang/String;> 
>>   18 iinc #1 1
>>   21 goto 2
>>   24 return
>
> Matias Saavedra Silva has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fixed code formatting

Marked as reviewed by iklam (Reviewer).

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PR: https://git.openjdk.org/jdk/pull/10860