RFR: 8254360: Re-examine use of CodeBuffer::verify_section_allocation [v2]

[Vladimir Kozlov]

On Wed, 25 Nov 2020 15:13:13 GMT, Claes Redestad <redestad at openjdk.org> wrote:

>> - In release builds, only call `verify_section_allocation` in `~CodeBuffer`. This reduce overhead, while retaining most of the verification promises in product builds.
>> - Minor touch-ups the implementation of `verify_section_allocation`: Use is_aligned. Add a `disjoint` predicate. Only compare two sections once per verification. Remove some redundant checks.
>
> Claes Redestad has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:
> 
>  - Fix copyright
>  - Fix indentation, copyright
>  - Merge branch 'master' into verify_section_alloc
>  - Merge branch 'master' into verify_section_alloc
>  - Merge branch 'master' into verify_section_alloc
>  - Ptrs schmtrs
>  - Factor out disjoint property, avoid redundant checks (disjointedness is symmetric)
>  - 8254360: Re-examine use of CodeBuffer::verify_section_allocation

Changes requested by kvn (Reviewer).

src/hotspot/share/asm/codeBuffer.hpp line 494:

> 492:     initialize_misc("static buffer");
> 493:     initialize(code_start, code_size);
> 494:     debug_only(verify_section_allocation();)

You also need #ifdef ASSERT around verify_section_allocation() in codeBuffer.cpp.

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PR: https://git.openjdk.java.net/jdk/pull/1421