RFR: 8255245: C1: Fix output of -XX:+PrintCFGToFile to open it with visualizer

[Nils Eliasson]

On Fri, 23 Oct 2020 13:16:27 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

> [JDK-8251093](https://bugs.openjdk.java.net/browse/JDK-8251093) introduced some improved logging for intervals. When specifying `-XX:+PrintCFGToFile` to dump the graph to a file to later open it with the C1 visualizer, it also uses the improved interval printing. However, this output can no longer be read by the C1 Visualizer. As the C1 Visualizer is not part of the JDK, we should include the old format again for the output produced by `-XX:+PrintCFGToFile` to be compatible with the visualizer again. The console output can still use the improved logging of JDK-8251093.

src/hotspot/share/c1/c1_LinearScan.cpp line 4607:

> 4605: 
> 4606: #ifndef PRODUCT
> 4607: void Interval::print_on(outputStream* out) const {

I suggest moving the impl of print_on to the declaration in the hpp-file. That will make it easier to see at a glance how the different print methods delegate to each other.

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PR: https://git.openjdk.java.net/jdk/pull/837