[lldb-dev] Various strange errors while debugging PostgreSQL

Aleksander Alekseev via lldb-dev lldb-dev at lists.llvm.org
Thu Mar 24 10:23:30 PDT 2016

> So I am guessing these are the only architectures that are supported.
> I am guessing you might be on an i386 system?

No I'm afraid it's x86_64. File RegisterContextPOSIXCore_x86_64.cpp is
present in source tree I used to build lldb.

This bug is very easy to reproduce.

0. You need Ubuntu 14.04 LTS x64 with latest updates
1. Create a new LXC container to exclude any possible side effects from
other installed applications
2. Build LLDB using this script: http://paste.ubuntu.com/15488691/
3. Run `sudo ninja install`
4. Create t.c:

#include <stdio.h>

int main()
  return 0;

5. Run ` /usr/local/bin/clang-3.8 t.c -o t ` (or ... -g - it doesn't
6. Then:

$ ./t
$ lldb ./t
(lldb) target create "./t"
Current executable set to './t' (x86_64).
(lldb) b main
Breakpoint 1: where = t`main, address = 0x0000000000400530
(lldb) r
Process 24974 launching
Process 24974 launched: './t' (x86_64)
Process 24974 stopped
* thread #1: tid = 24974, 0x0000000000400530 t`main, name = 't', stop
reason = breakpoint 1.1 frame #0: 0x0000000000400530 t`main
-> 0x400530 <main>: pushq  %rbp
   0x400531 <main+1>: movq   %rsp, %rbp
   0x400534 <main+4>: subq   $0x10, %rsp
   0x400538 <main+8>: movabsq $0x4005e4, %rdi
(lldb) process save-core /tmp/1.core

error: Failed to save core file for process: no ObjectFile plugins were
able to save a core for this process

(lldb) ^D

Best regards,
Aleksander Alekseev

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