JEP 228: Add More Diagnostic Commands

Summary

Define additional diagnostic commands, in order to improve the diagnosability of Hotspot and the JDK.

Description

This is a list of the new commands (exact names are TBD):

print_class_summary

• Print a list of all loaded classes and their inheritence structure.
• Responsible group: runtime

print_codegenlist

• Print methods queued for compilation with either C1 or C2 (separate queues)
• Responsible group: compiler

print_utf8pool

• Print all UTF-8 string constants.
• Responsible group: runtime

datadump_request

• Signal the JVM to do a data-dump request for JVMTI.
• Responsible group: serviceability

dump_codelist

• Print n-methods (compiled) with full signature, address range, and state (alive, nonentrant, and zombie).
• Allow selection of printing to stdout or to a file.
• Allow XML or text printout.
• Responsible group: compiler

print_codeblocks

• Print the size of the code cache and a list of blocks in the code cache, with adresses.
• Responsible group: compiler

set_vmflag

• Set a command-line flag/option in VM or the libraries.
• Responsible group: servicability

Testing

There needs to be a test for each command to verify the output.