* Using symbol map file with gdb? @ 2023-07-20 20:30 Roger Phillips via Gdb 2023-07-20 20:55 ` Jan Vrany via Gdb 2023-07-21 9:46 ` Andrew Haley via Gdb 0 siblings, 2 replies; 6+ messages in thread From: Roger Phillips via Gdb @ 2023-07-20 20:30 UTC (permalink / raw) To: gdb Greetings, I need to debug a segfault in java native code but the callstacks have no method names. Is it possible to import a symbol map file created with, say perf map agent into gdb? If yes, how? https://github.com/jvm-profiling-tools/perf-map-agent/tree/master ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Using symbol map file with gdb? 2023-07-20 20:30 Using symbol map file with gdb? Roger Phillips via Gdb @ 2023-07-20 20:55 ` Jan Vrany via Gdb 2023-07-21 9:46 ` Roger Phillips via Gdb 2023-07-22 13:25 ` Roger Phillips via Gdb 2023-07-21 9:46 ` Andrew Haley via Gdb 1 sibling, 2 replies; 6+ messages in thread From: Jan Vrany via Gdb @ 2023-07-20 20:55 UTC (permalink / raw) To: Roger Phillips, gdb Hi, On Thu, 2023-07-20 at 20:30 +0000, Roger Phillips via Gdb wrote: > Greetings, > > I need to debug a segfault in java native code but the callstacks have no method names. Is it possible to import a symbol map file created with, say perf map agent into gdb? If yes, how? > > https://github.com/jvm-profiling-tools/perf-map-agent/tree/master I do not think this is possible with current GDB. However, a year ago or so I implemented new Python API that allows one to register new functions (symbols) at runtime. I used this for similar purpose, to get a meaningful backtrace of Java code in GDB [1] The code is at sourceware.org. To use perf map. you'd essentially need to parse the map file in Python and then call the new API to get symbols registered in GDB, in essence you'd need to do something like: # assuming that # name contains Java method descriptor # code is method's entry point # size is method's code size objfile = gdb.Objfile(name) symtab = gdb.Symtab(objfile, "SomeJavaClass.java") symtab.add_block(name, code, code + size) # If you have line number info, you may want to # build a linetable and GDB would show the source # code... symtab.set_linetable([ gdb.LineTableEntry(29, code, True), gdb.LineTableEntry(30, code+3, True), gdb.LineTableEntry(31, code+6, True) ]) I plan to upstream the code, but sadly it is still not polished enough to submit it :-( HTH, Jan [1]: https://github.com/janvrany/openj9-gdb/tree/master [2]: https://sourceware.org/git/?p=binutils-gdb.git;a=shortlog;h=refs/heads/users/jv/wip/feature-py-jit-api ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Using symbol map file with gdb? 2023-07-20 20:55 ` Jan Vrany via Gdb @ 2023-07-21 9:46 ` Roger Phillips via Gdb 2023-07-22 13:25 ` Roger Phillips via Gdb 1 sibling, 0 replies; 6+ messages in thread From: Roger Phillips via Gdb @ 2023-07-21 9:46 UTC (permalink / raw) To: Jan Vrany, gdb This would make the life of many java debuggers a lot easier. Is there a ticket that I can put on watchlist? ________________________________ From: Jan Vrany <jan@vrany.io> Sent: Thursday, July 20, 2023 8:55 PM To: Roger Phillips <heidegg@hotmail.com>; gdb@sourceware.org <gdb@sourceware.org> Subject: Re: Using symbol map file with gdb? Hi, On Thu, 2023-07-20 at 20:30 +0000, Roger Phillips via Gdb wrote: > Greetings, > > I need to debug a segfault in java native code but the callstacks have no method names. Is it possible to import a symbol map file created with, say perf map agent into gdb? If yes, how? > > https://github.com/jvm-profiling-tools/perf-map-agent/tree/master I do not think this is possible with current GDB. However, a year ago or so I implemented new Python API that allows one to register new functions (symbols) at runtime. I used this for similar purpose, to get a meaningful backtrace of Java code in GDB [1] The code is at sourceware.org. To use perf map. you'd essentially need to parse the map file in Python and then call the new API to get symbols registered in GDB, in essence you'd need to do something like: # assuming that # name contains Java method descriptor # code is method's entry point # size is method's code size objfile = gdb.Objfile(name) symtab = gdb.Symtab(objfile, "SomeJavaClass.java") symtab.add_block(name, code, code + size) # If you have line number info, you may want to # build a linetable and GDB would show the source # code... symtab.set_linetable([ gdb.LineTableEntry(29, code, True), gdb.LineTableEntry(30, code+3, True), gdb.LineTableEntry(31, code+6, True) ]) I plan to upstream the code, but sadly it is still not polished enough to submit it :-( HTH, Jan [1]: https://github.com/janvrany/openj9-gdb/tree/master [2]: https://sourceware.org/git/?p=binutils-gdb.git;a=shortlog;h=refs/heads/users/jv/wip/feature-py-jit-api ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Using symbol map file with gdb? 2023-07-20 20:55 ` Jan Vrany via Gdb 2023-07-21 9:46 ` Roger Phillips via Gdb @ 2023-07-22 13:25 ` Roger Phillips via Gdb 2023-07-22 17:21 ` Andrew Haley via Gdb 1 sibling, 1 reply; 6+ messages in thread From: Roger Phillips via Gdb @ 2023-07-22 13:25 UTC (permalink / raw) To: gdb, aph For some reason your mail was only in the archive not in my inbox. Let's see if this works out: Do these debug helpers exists in Zulu VM which is based on OpenJDK? https://docs.azul.com/core/ Azul Zulu Builds of OpenJDK<https://docs.azul.com/core/> docs.azul.com docs.azul.com If yes, how to activate them? Do they produce full stack frames with parameters etc. ? ________________________________ From: Andrew Haley <aph@redhat.com<mailto:aph%40redhat.com?Subject=Re:%20Re%3A%20Using%20symbol%20map%20file%20with%20gdb%3F&In-Reply-To=%3Ce64d2692-9055-f05e-18e5-6e7e423b3949%40redhat.com%3E>> Sent: Thursday, July 20, 2023 8:55 PM To: Roger Phillips <heidegg@hotmail.com>; gdb@sourceware.org <gdb@sourceware.org> Subject: Re: Using symbol map file with gdb? Just in case you didn't already know this: If your JVM is HotSpot then it contains the debug helpers to handle debugging generated/interpreted code. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Using symbol map file with gdb? 2023-07-22 13:25 ` Roger Phillips via Gdb @ 2023-07-22 17:21 ` Andrew Haley via Gdb 0 siblings, 0 replies; 6+ messages in thread From: Andrew Haley via Gdb @ 2023-07-22 17:21 UTC (permalink / raw) To: Roger Phillips, gdb On 7/22/23 14:25, Roger Phillips wrote: > For some reason your mail was only in the archive not in my inbox. Let's see if this works out: > > Do these debug helpers exists in Zulu VM which is based on OpenJDK? I doubt it. But trying to debug segfaults in non-debug builds of OpenJDK is a difficult thing to do anyway. -- Andrew Haley (he/him) Java Platform Lead Engineer Red Hat UK Ltd. <https://www.redhat.com> https://keybase.io/andrewhaley EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671 ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Using symbol map file with gdb? 2023-07-20 20:30 Using symbol map file with gdb? Roger Phillips via Gdb 2023-07-20 20:55 ` Jan Vrany via Gdb @ 2023-07-21 9:46 ` Andrew Haley via Gdb 1 sibling, 0 replies; 6+ messages in thread From: Andrew Haley via Gdb @ 2023-07-21 9:46 UTC (permalink / raw) To: gdb On 7/20/23 21:30, Roger Phillips via Gdb wrote: > I need to debug a segfault in java native code but the callstacks have no method names. Is it possible to import a symbol map file created with, say perf map agent into gdb? If yes, how? Just in case you didn't already know this: If your JVM is HotSpot then it contains the debug helpers to handle debugging generated/interpreted code. -- Andrew Haley (he/him) Java Platform Lead Engineer Red Hat UK Ltd. <https://www.redhat.com> https://keybase.io/andrewhaley EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671 ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-07-22 17:22 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2023-07-20 20:30 Using symbol map file with gdb? Roger Phillips via Gdb 2023-07-20 20:55 ` Jan Vrany via Gdb 2023-07-21 9:46 ` Roger Phillips via Gdb 2023-07-22 13:25 ` Roger Phillips via Gdb 2023-07-22 17:21 ` Andrew Haley via Gdb 2023-07-21 9:46 ` Andrew Haley via Gdb
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