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From: George Timoshenko <george.timoshenko@gmail.com>
Subject: Re: [drlvm][jvmti] Profiling support - Compiled Method Load event
Date: Tue, 05 Dec 2006 14:24:04 +0600
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Egor Pasko wrote:
> On the 0x235 day of Apache Harmony George Timoshenko wrote:
>> Eugene,
>>
>> I've answered in JIRA:
>>
>> https://issues.apache.org/jira/browse/HARMONY-2145#action_12455313
>>
>> (Summary: Everything is OK)
>>
>> For this particular testcase it is possible. But there is a general
>> problem:
>>
>> Code layout may be quite unordered. (It mostly depends on hottness,
>> not the instructions<->method relations) So a method (say A) body
>> can be layouted at two (or more) unsuccessive regions.  And the
>> regeion between them can belong to some another method (say B). And
>> B is _not_ inlined into A.
> 
> That is essential, an inlined method can be separated in
> non-contiguous regions for performance during CFG alignment. IMHO, we
> should register several code blocks for the same inlined method (if
> the method's code was split into parts) through the
> compiled_method_load(...) interface. This can be done completely on
> the JIT side.
> 
> What do you, guys, think?

No doubts it can be done on the JIT side, but what is the purpose of it?

If there is only one question: "I get instruction, which method does it 
belong to?" it can be answerd easily:

For each method jvmtiAddrLocationMap is reported. And each instruction 
(with particular codeAddress) belongs to the only one such map.

I do not understand the necessity of reporting each piece (a number of 
instructions that goes in a row and belongs to the same method) of a 
method while we are already reporting _each_instruction_ separately.