JosephTremoulet added a comment.
@jasonmolenda @clayborg ping. To clarify, the issue this fixes is, using test
functionalities/signal/handle-abrt as an example:
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
void handler(int sig)
{
printf("Set a breakpoint here.\n");
exit(0);
}
void abort_caller() {
abort();
}
int main()
{
if (signal(SIGABRT, handler) == SIG_ERR)
{
perror("signal");
return 1;
}
abort_caller();
return 2;
}
When stopped at the breakpoint in "handler", backtrace currently gives this:
(lldb) bt
* thread #1, name = 'sigtest', stop reason = breakpoint 1.1
* frame #0: 0x0000000000400651 sigtest`handler(sig=6) at main.c:7
frame #1: 0x00007ffff7a424b0 libc.so.6`___lldb_unnamed_symbol1$$libc.so.6
+ 1 <----- the symbol context of this frame is the issue
frame #2: 0x00007ffff7a42428 libc.so.6`__GI_raise(sig=6) at raise.c:54
frame #3: 0x00007ffff7a4402a libc.so.6`__GI_abort at abort.c:89
frame #4: 0x000000000040066e sigtest`abort_caller() at main.c:12
frame #5: 0x00000000004006a2 sigtest`main at main.c:23
frame #6: 0x00007ffff7a2d830
libc.so.6`__libc_start_main(main=(sigtest`main at main.c:16), argc=1,
argv=0x00007fffffffe328, init=<unavailable>, fini=<unavailable>,
rtld_fini=<unavailable>, stack_end=0x00007fffffffe318) at libc-start.c:291
frame #7: 0x0000000000400579 sigtest`_start + 41
the pc of frame 1 is actually on the first byte of the relevant function, not
following a call:
(lldb) frame select 1
frame #1: 0x00007ffff7a424b0 libc.so.6`___lldb_unnamed_symbol1$$libc.so.6 + 1
libc.so.6`__restore_rt:
-> 0x7ffff7a424b0 <+0>: movq $0xf, %rax
0x7ffff7a424b7 <+7>: syscall
0x7ffff7a424b9 <+9>: nopl (%rax)
libc.so.6`__GI___libc_sigaction:
0x7ffff7a424c0 <+0>: subq $0xd0, %rsp
(lldb) disassemble -s '$pc - 2'
0x7ffff7a424ae: addb %al, (%rax)
libc.so.6`__restore_rt:
-> 0x7ffff7a424b0 <+0>: movq $0xf, %rax
0x7ffff7a424b7 <+7>: syscall
0x7ffff7a424b9 <+9>: nopl (%rax)
libc.so.6`__GI___libc_sigaction:
0x7ffff7a424c0 <+0>: subq $0xd0, %rsp
0x7ffff7a424c7 <+7>: testq %rsi, %rsi
0x7ffff7a424ca <+10>: movq %rdx, %r8
With this fix, we instead get this backtrace:
(lldb) bt
* thread #1, name = 'sigtest', stop reason = breakpoint 1.1
* frame #0: 0x0000000000400651 sigtest`handler(sig=6) at main.c:7
frame #1: 0x00007ffff7a424b0 libc.so.6`__restore_rt
<-------------- correct symbol context here
frame #2: 0x00007ffff7a42428 libc.so.6`__GI_raise(sig=6) at raise.c:54
frame #3: 0x00007ffff7a4402a libc.so.6`__GI_abort at abort.c:89
frame #4: 0x000000000040066e sigtest`abort_caller() at main.c:12
frame #5: 0x00000000004006a2 sigtest`main at main.c:23
frame #6: 0x00007ffff7a2d830
libc.so.6`__libc_start_main(main=(sigtest`main at main.c:16), argc=1,
argv=0x00007fffffffe328, init=<unavailable>, fini=<unavailable>,
rtld_fini=<unavailable>, stack_end=0x00007fffffffe318) at libc-start.c:291
frame #7: 0x0000000000400579 sigtest`_start + 41
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D64993/new/
https://reviews.llvm.org/D64993
_______________________________________________
lldb-commits mailing list
lldb-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
