RFR: 8354520: IGV: dump contextual information [v4]

[Damon Fenacci]

On Thu, 24 Apr 2025 10:55:37 GMT, Roberto Castañeda Lozano <rcastanedalo at openjdk.org> wrote:

>> This changeset extends the IGV graph dumps with additional properties that ease tracing the dumps back to the context in which they were produced. The changeset dumps, for every compilation, the following additional properties:
>> 
>> - JVM arguments
>> - platform information
>> - JVM version information
>> - date and time
>> - process ID
>> - (compiler) thread ID
>> 
>> ![compilation-properties](https://github.com/user-attachments/assets/8ddc8fb9-c348-4761-8e19-c70633a1b59f)
>> 
>> Additionally, the changeset produces and dumps the C2 stack trace from which each graph is dumped:
>> 
>> ![c2-stack-trace](https://github.com/user-attachments/assets/085547ee-b0b3-4a38-86f1-9df79cf1cc01)
>> 
>> This should be particularly useful in an interactive context, where the user steps through C2 code using a debugger and dumps graphs at different points. To produce a stack trace in this context, the usual debugger-entry C2 functions (`igv_print`, `igv_append`, `Node::dump_bfs`, ...) are extended with extra arguments to specify the stack handling registers (stack pointer, frame pointer, and program counter):
>> 
>> ![c2-stack-trace-from-gdb](https://github.com/user-attachments/assets/29de2964-ee2d-4f5f-bcf7-d81e1bc6c8a6)
>> 
>> The inconvenience of manually specifying the stack handling registers can be addressed by hiding them in debugger user-defined commands, e.g.:
>> 
>> 
>> define igv
>>   p igv_print(true, $sp, $fp, $pc)
>> end
>> 
>> define igv_node
>>   p find_node($arg0)->dump_bfs(0, 0, "!", $sp, $fp, $pc)
>> end
>> 
>> 
>> Thanks to @TobiHartmann for providing useful feedback!
>> 
>> #### Testing
>> 
>>  - tier1 (windows-x64, linux-x64, linux-aarch64, macosx-x64, and macosx-aarch64; release and debug mode).
>>  - Tested interactive usage manually via `gdb` and `rr` on linux-x64.
>>  - Tested automatically that dumping thousands of graphs does not trigger any assertion failure.
>
> Roberto Castañeda Lozano has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add relative link to compile.cpp

src/hotspot/share/opto/node.cpp line 2061:

> 2059:       Compile* C = Compile::current();
> 2060:       C->init_igv();
> 2061:       C->igv_print_graph_to_network(nullptr, _print_list, _frame);

I suppose you removed "PrintBFS" to make the graph name be "Debug" like the other ones and make it easier to handle name and stack printing right?

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PR Review Comment: https://git.openjdk.org/jdk/pull/24724#discussion_r2068579904