RFR: 8279057: Consolidate InstructionPrinter::do_BlockBegin and remove extra lines in logs of blocks with phi functions

[Hamlin Li]

On Thu, 23 Dec 2021 12:43:13 GMT, Yi Yang <yyang at openjdk.org> wrote:

>> This pr does following things:
>>  - First, the code related to printing phi in InstructionPrinter::do_BlockBegin is bit redudant, it could be consolidated;
>>  - Second, only locals and stack values related to phi functions are printed out now.
>>  - Third, there are extra blank lines in printed log of blocks with phi functions, these blank lines are better to be removed.
>
> src/hotspot/share/c1/c1_InstructionPrinter.cpp line 639:
> 
>> 637:       if (v && is_phi_of_block(v, x)) {
>> 638:         if (!printed_phis_in_locals_header) {
>> 639:           output()->cr(); output()->print("Values in locals related to phi functions:");
> 
> Can we keep this old style? i.e. "Locals:" and "Stacks:".

Thanks @kelthuzadx 
As this patch is modifying some output content, I'm not quite sure if the labels should be modified accordingly. 
I do understand your concerns, Let's see how others think about it.

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PR: https://git.openjdk.java.net/jdk/pull/6921