RFR: 8279570: IGV: Add source/destination property for load and store nodes with an associated field [v2]

[Tobias Hartmann]

On Thu, 13 Jan 2022 08:36:57 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

>> This patch adds a source/destination property field in the "Properties" view for a load/store node associated with a field in IGV. This simplifies the analysis of graphs when dealing with multiple loads/stores from/to fields.
>> 
>> For each node, we are trying to get the associated `ciField` (`get_field()`). This works fine for direct field load/stores nodes. However, when facing an array access, we need to find the actual node doing the field access to get the `ciField` from. For that purpose, I added an additional search based on pattern matching (`find_source_field_of_array_access()`). It follows the address input of a load/store to find the field `LoadN` (compressed oops) or `LoadP` (non-compressed oops) from which we can get the `ciField`.
>> 
>> Example:
>> 
>> iFld = 1; // StoreI 25 (not shown in graph)
>> iArrFld[2] = 3; // StoreI 67
>> x = iArrFld2[4][5]; // LoadI 138
>> 
>> ![Screenshot from 2022-01-07 15-12-41](https://user-images.githubusercontent.com/17833009/149097102-6192f9c1-72a5-4941-bf92-ff0f59018e08.png)
>> 
>> ![Screenshot from 2022-01-07 15-18-15](https://user-images.githubusercontent.com/17833009/149098172-0d750445-9e26-42da-82ff-7627428a4c12.png)
>> 
>> - `StoreI 25`: Can directly fetch the field `iFld` with `get_field()`.
>> - `StoreI 67`: For the store to an array, we follow the address input `AddP 66` -> `46 CastPP` -> `29 DecodeN` -> `28 LoadN` to get the field `iFldArr` from `28 LoadN` (done in `find_source_field_of_array_access()`)
>> - `LoadI 138`: Same as for `StoreI 67` but we repeat the loop in `find_source_field_of_array_access()` when reaching `LoadI 138` -> ... -> `104 LoadN` to get the field `iArrFld2` eventually from `70 LoadN`.
>> 
>> I additionally ran the following sanity testing with a Hello World program:
>> 
>> java -XX:-TieredCompilation -Xcomp -XX:+PrintIdealGraph -XX:PrintIdealGraphLevel=3 -XX:PrintIdealGraphFile=graph.xml HelloWorld.java
>> 
>> Thanks,
>> Christian
>
> Christian Hagedorn has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Change to Node::uncast

Looks good.

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Marked as reviewed by thartmann (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/7048