RFR: 8261336: IGV: enhance default filters [v2]

[Christian Hagedorn]

On Mon, 15 Feb 2021 11:15:11 GMT, Roberto Castañeda Lozano <rcastanedalo at openjdk.org> wrote:

>> Redesign the filters shown by default in the "Filters" window:
>> 
>> - Add filters to color the graph by node category and execution frequency (if applicable), and to hide subgraphs or edges only by _category_. The category of a node can be one of {`data`, `memory`, `control`, `mixed`, `other`}, and is solely determined by its type. `mixed` nodes are those with a tuple type that has different categories, such as `CallStaticJavaNode`. The category of an edge is that of its source node.
>> 
>> - Instrument C2 to include the category and estimated execution frequency (if available) of each node in the graph dumps produced by `-XX:PrintIdealGraphLevel=N` (only in debug builds).
>> 
>> - Remove filters which depend on properties never emitted by C2 (e.g. 'Remove State') or which appear to be unused ('C2 Matcher Flags Coloring' and 'C2 Register Coloring'). Also remove the subsumed 'C2 Basic Coloring' filter. 
>> 
>> - Merge 'C2 Remove Filter' and 'C2 Structural' into a single filter with a clearer name ('Simplify graph').
>> 
>> ### Screenshots
>> 
>> "Filters" window before (left) and after (right) the proposed change:
>> ![filters-window](https://user-images.githubusercontent.com/8792647/107749859-7a664780-6d1b-11eb-84ba-fd43e13abd0e.png)
>> Default color scheme before (left) and after (right) the proposed change:
>> ![color-scheme](https://user-images.githubusercontent.com/8792647/107517355-f3479100-6bad-11eb-9b0b-a71c18961dd8.png)
>> Examples of the new 'Color by execution frequency' filter:
>> ![color-by-frequency-2](https://user-images.githubusercontent.com/8792647/107518492-5980e380-6baf-11eb-9e01-992b211d06e3.png)
>> ![color-by-frequency-1](https://user-images.githubusercontent.com/8792647/107518477-54bc2f80-6baf-11eb-8c7b-7eb7c1d85cf7.png)
>> Example of the new 'Hide X subgraph'' filters, where only the data subgraph is shown:
>> ![hide-all-but-data-subgraphs](https://user-images.githubusercontent.com/8792647/107750398-42133900-6d1c-11eb-8b27-264086b32bea.png)
>> Example of the new 'Hide X edges' filters, where all nodes remain in their position but only the memory edges are shown:
>> ![hide-all-but-memory-edges](https://user-images.githubusercontent.com/8792647/107751137-49871200-6d1d-11eb-9df0-79747bf8d16e.png)
>> 
>> 
>> Tested IGV manually on a few graphs. Tested C2 instrumentation by running `hs-tier1` with `-Xbatch -XX:PrintIdealGraphLevel=3 -XX:PrintIdealGraphFile=graph.xml` on windows-x64, linux-x64, linux-aarch64, and macosx-x64 (all debug).
>
> Roberto Castañeda Lozano has updated the pull request incrementally with five additional commits since the last revision:
> 
>  - Rewrite 'Show control flow only' filter using categories
>  - Add leading underscore field
>  - Move assertion to a default switch case
>  - Indent switch statements
>  - Use a scoped enum for type categories (as per the HotSpot style guide)

Thanks for addressing my suggestions. I tested it again - looks good!

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Marked as reviewed by chagedorn (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/2499