From 1ab139e5bedfec2bb277287574cc0322c21a252b Mon Sep 17 00:00:00 2001 From: Luis Machado Date: Thu, 9 Jan 2020 16:19:31 -0300 Subject: [PATCH] Add more debugging output to aarch64_displaced_step_fixup While debugging the step-over-syscall problem, i wanted to see a bit more debugging output to try to determine the root cause. This patch does this. gdb/ChangeLog: 2020-01-21 Luis Machado * aarch64-tdep.c (aarch64_displaced_step_fixup): Add more debugging output. --- gdb/ChangeLog | 5 +++++ gdb/aarch64-tdep.c | 27 +++++++++++++++++++++++++-- 2 files changed, 30 insertions(+), 2 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 146767f0697..ec9bac0dad3 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2020-01-21 Luis Machado + + * aarch64-tdep.c (aarch64_displaced_step_fixup): Add more debugging + output. + 2020-01-21 Luis Machado * aarch64-tdep.c (struct aarch64_displaced_step_closure ) diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c index fb7b8621ba2..03d650d9dc5 100644 --- a/gdb/aarch64-tdep.c +++ b/gdb/aarch64-tdep.c @@ -3037,8 +3037,16 @@ aarch64_displaced_step_fixup (struct gdbarch *gdbarch, regcache_cooked_read_unsigned (regs, AARCH64_PC_REGNUM, &pc); + if (debug_displaced) + debug_printf ("Displaced: PC after stepping: %s (was %s).\n", + paddress (gdbarch, pc), paddress (gdbarch, to)); + if (dsc->cond) { + if (debug_displaced) + debug_printf ("Displaced: [Conditional] pc_adjust before: %d\n", + dsc->pc_adjust); + if (pc - to == 8) { /* Condition is true. */ @@ -3050,8 +3058,18 @@ aarch64_displaced_step_fixup (struct gdbarch *gdbarch, } else gdb_assert_not_reached ("Unexpected PC value after displaced stepping"); + + if (debug_displaced) + debug_printf ("Displaced: [Conditional] pc_adjust after: %d\n", + dsc->pc_adjust); } + if (debug_displaced) + debug_printf ("Displaced: %s PC by %d\n", + dsc->pc_adjust? "adjusting" : "not adjusting", + dsc->pc_adjust); + + if (dsc->pc_adjust != 0) { /* Make sure the previous instruction was executed (that is, the PC @@ -3059,11 +3077,16 @@ aarch64_displaced_step_fixup (struct gdbarch *gdbarch, offset. Otherwise we may skip an instruction before its execution took place. */ if ((pc - to) == 0) - dsc->pc_adjust = 0; + { + if (debug_displaced) + debug_printf ("Displaced: PC did not move. Discarding PC " + "adjustment.\n"); + dsc->pc_adjust = 0; + } if (debug_displaced) { - debug_printf ("displaced: fixup: set PC to %s:%d\n", + debug_printf ("Displaced: fixup: set PC to %s:%d\n", paddress (gdbarch, from), dsc->pc_adjust); } regcache_cooked_write_unsigned (regs, AARCH64_PC_REGNUM, -- 2.30.2