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gdb+gdbserver/Linux: Remove USE_SIGTRAP_SIGINFO fallback

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It's been over 9 years (since commit faf09f0119) since Linux GDB and
GDBserver started relying on SIGTRAP si_code to tell whether a
breakpoint triggered, which is important for non-stop mode.  When that
then-new code was added, I had left the then-old code as fallback, in
case some architectured still needed it.  Given AFAIK there haven't
been complaints since, this commit finally removes the fallback code,
along with USE_SIGTRAP_SIGINFO.

Change-Id: I140a5333a9fe70e90dbd186aca1f081549b2e63d
This commit is contained in:
Pedro Alves
2024-04-17 18:20:35 +01:00
parent c7d73a7157
commit 5739a1b98d
3 changed files with 8 additions and 95 deletions
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53
gdb/linux-nat.c
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@@ -2633,18 +2633,6 @@ status_callback (struct lwp_info *lp)
discard = 1;
}
#if !USE_SIGTRAP_SIGINFO
else if (!breakpoint_inserted_here_p (lwp_inferior (lp)->aspace, pc))
{
linux_nat_debug_printf ("previous breakpoint of %s, at %s gone",
lp->ptid.to_string ().c_str (),
paddress (current_inferior ()->arch (),
lp->stop_pc));
discard = 1;
}
#endif
if (discard)
{
linux_nat_debug_printf ("pending event of %s cancelled.",
@@ -2724,9 +2712,7 @@ save_stop_reason (struct lwp_info *lp)
struct gdbarch *gdbarch;
CORE_ADDR pc;
CORE_ADDR sw_bp_pc;
#if USE_SIGTRAP_SIGINFO
siginfo_t siginfo;
#endif
gdb_assert (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON);
gdb_assert (lp->status != 0);
@@ -2744,7 +2730,6 @@ save_stop_reason (struct lwp_info *lp)
pc = regcache_read_pc (regcache);
sw_bp_pc = pc - gdbarch_decr_pc_after_break (gdbarch);
#if USE_SIGTRAP_SIGINFO
if (linux_nat_get_siginfo (lp->ptid, &siginfo))
{
if (siginfo.si_signo == SIGTRAP)
@@ -2787,21 +2772,6 @@ save_stop_reason (struct lwp_info *lp)
}
}
}
#else
if ((!lp->step || lp->stop_pc == sw_bp_pc)
&& software_breakpoint_inserted_here_p (inf->aspace, sw_bp_pc))
{
/* The LWP was either continued, or stepped a software
breakpoint instruction. */
lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
}
if (hardware_breakpoint_inserted_here_p (inf->aspace, pc))
lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
if (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON)
check_stopped_by_watchpoint (lp);
#endif
if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT)
{
@@ -2847,7 +2817,7 @@ linux_nat_target::stopped_by_sw_breakpoint ()
bool
linux_nat_target::supports_stopped_by_sw_breakpoint ()
{
return USE_SIGTRAP_SIGINFO;
return true;
}
/* Returns true if the LWP had stopped for a hardware
@@ -2868,7 +2838,7 @@ linux_nat_target::stopped_by_hw_breakpoint ()
bool
linux_nat_target::supports_stopped_by_hw_breakpoint ()
{
return USE_SIGTRAP_SIGINFO;
return true;
}
/* Select one LWP out of those that have events pending. */
@@ -3461,25 +3431,6 @@ linux_nat_wait_1 (ptid_t ptid, struct target_waitstatus *ourstatus,
gdb_assert (lp != NULL);
/* Now that we've selected our final event LWP, un-adjust its PC if
it was a software breakpoint, and we can't reliably support the
"stopped by software breakpoint" stop reason. */
if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
&& !USE_SIGTRAP_SIGINFO)
{
struct regcache *regcache = get_thread_regcache (linux_target, lp->ptid);
struct gdbarch *gdbarch = regcache->arch ();
int decr_pc = gdbarch_decr_pc_after_break (gdbarch);
if (decr_pc != 0)
{
CORE_ADDR pc;
pc = regcache_read_pc (regcache);
regcache_write_pc (regcache, pc + decr_pc);
}
}
/* We'll need this to determine whether to report a SIGSTOP as
GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
clears it. */