RFR: JDK-8302335: IGV: Bytecode not showing [v2]

[Tobias Holenstein]

On Wed, 15 Feb 2023 15:36:45 GMT, Tobias Holenstein <tholenstein at openjdk.org> wrote:

>> Currently, IGV does not show the bytecode of a graph in the "Bytecode" window although the bytecode is present in the XML file.
>> 
>> # Solution
>> 
>> Following is the `<bytecodes>` block of the XML file
>> 
>> <bytecodes>
>> <![CDATA[
>>    0 iconst_3
>>    1 istore_1
>>    2 bipush 9
>>    4 istore_2
>>    5 iload_2
>>    6 ifle 34
>>   0   bci: 6    BranchData          taken(0) displacement(112) not taken(0)
>>    9 iconst_2
>>   10 istore_3
>>   11 iload_3
>>   12 iload_2
>>   13 if_icmpge 28
>>   32  bci: 13   BranchData          taken(0) displacement(56)  not taken(0)
>>   16 iload_1
>>   17 istore_1
>>   18 iconst_1
>>   19 iload_3
>>   20 irem
>>   21 istore_1
>>   22 iinc #3 1
>>   25 goto 11
>>   64  bci: 25   JumpData            taken(0) displacement(-32)
>>   28 iinc #2 -1
>>   31 goto 5
>>   88  bci: 31   JumpData            taken(0) displacement(-88)
>>   34 return
>> ]]>
>> </bytecodes>
>> 
>> The problem was that during paring IGV skipped all lines that started with an empty space: This just skipped all bytecodes. We only want to skip bytecode like `  0   bci: 6    BranchData          taken(0) displacement(112) not taken(0)` . Meaning: whitespace - number - exactly two white spaces - and then arbitrary text.
>> 
>> <img width="283" alt="bytecode" src="https://user-images.githubusercontent.com/71546117/218495199-2b02a79c-3065-404c-af57-3f8a603ac499.png">
>
> Tobias Holenstein has updated the pull request incrementally with one additional commit since the last revision:
> 
>   support old and new bytecode format

> The method data still shows up for me:
> 
> ![Screenshot from 2023-02-16 13-39-18](https://user-images.githubusercontent.com/5312595/219367453-aed3f86d-de6c-4a54-9df5-bb5095e26026.png)



> The method data still shows up for me:
> 
> ![Screenshot from 2023-02-16 13-39-18](https://user-images.githubusercontent.com/5312595/219367453-aed3f86d-de6c-4a54-9df5-bb5095e26026.png)

Thanks for catching that! 
This is actually a bug in printing the bytecodes on the VM side: [JDK-8302656](https://bugs.openjdk.org/browse/JDK-8302656)
I adjusted the PR to work even in the presents of the bug (and still work when it is fixed)

-------------

PR: https://git.openjdk.org/jdk/pull/12537