Integrated: 8356761: IGV: dump escape analysis information

[Anton Seoane Ampudia]

On Thu, 30 Oct 2025 13:49:44 GMT, Anton Seoane Ampudia <aseoane at openjdk.org> wrote:

> This PR introduces new IGV dumps, property fields and filters related to escape analysis information.
> 
> The C2 escape analysis algorithm is carried out in six primary steps, of which many have interesting sub-steps (e.g. `split_unique_types`) or present an iterative nature where access to intermediate results can aid debugging and analysis. Additionally, escape analysis relies on an "intermediate structure" called the _connection graph_, which is also particularly valuable for deeper investigations.
> 
> With this changeset, escape analysis information is now dumped at key points throughout the algorithm, with a degree of granularity (from only the basic steps to in-detail iterative dumping). The dumps include several property fields, such as:
> 
> - Node escape “level”.
> - Scalar replaceability.
> - Node type within the connection graph (per [C2 Escape Analysis connection graph](https://wiki.openjdk.org/display/HotSpot/EscapeAnalysis)).
> 
> This is achieved by passing the `ConnectionGraph` in use to the `IdealGraphPrinter` during escape analysis, so that these properties can be dumped. After escape analysis, remaining interesting information that is left until macro elimination (and consequent elimination of non-escaping, replaceable allocations) is also dumped.
> 
> Additionally, two filters are provided: one for displaying the connection node type in the IGV node box, and another one for color-scaling nodes based on their escaping/scalar status.
> 
> **Testing:** passes tiers 1-3, manual testing in IGV

This pull request has now been integrated.

Changeset: 0829c6ac
Author:    Anton Seoane Ampudia <aseoane at openjdk.org>
Committer: Roberto Castañeda Lozano <rcastanedalo at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/0829c6acde496833300efb38b4b900bf94b99dc0
Stats:     205 lines in 10 files changed: 200 ins; 1 del; 4 mod

8356761: IGV: dump escape analysis information

Reviewed-by: rcastanedalo, chagedorn

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PR: https://git.openjdk.org/jdk/pull/28060