RFR: 8370569: IGV: dump more graph properties at bytecode parsing
Roberto Castañeda Lozano
rcastanedalo at openjdk.org
Fri Oct 24 12:33:37 UTC 2025
This changeset makes it easier to trace C2's individual bytecode parsing steps to the input class files and the output of type flow analysis, by:
1. dumping the `map` node (holding the JVM state), basic block (reverse post-order index), and method name as properties of the graph that C2 dumps after each parsed bytecode at IGV dump level 6;
2. appending this information to the graph name (hence generalizing [JDK-8356779](https://bugs.openjdk.org/browse/JDK-8356779)); and
3. making the graph name suffix configurable via `Options -> Graph Name Suffix`. By default, it appends `(map: [map], block #[block] at [method])` to the names of graphs containing these properties (bytecode parsing dumps), and nothing otherwise.
Here are the `Outline` and `Properties` windows for
$ java -Xbatch -XX:CompileOnly=java.lang.String::charAt -XX:PrintIdealGraphLevel=6
before (left) and after (right) the changeset:
<img width="2537" height="1032" alt="before-after" src="https://github.com/user-attachments/assets/cbd78f21-2501-4dcf-b757-86a556002d95" />
Please let me know if there are other bytecode parsing graph properties that could be useful to dump, and whether you think the default graph name suffix contains the right amount of information.
#### Testing
- tier1.
- Tested automatically that dumping thousands of graphs does not trigger any assertion failure on HotSpot or IGV.
-------------
Commit messages:
- Initial commit
Changes: https://git.openjdk.org/jdk/pull/27975/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27975&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8370569
Stats: 155 lines in 9 files changed: 106 ins; 13 del; 36 mod
Patch: https://git.openjdk.org/jdk/pull/27975.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/27975/head:pull/27975
PR: https://git.openjdk.org/jdk/pull/27975
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