On 2012-06-11 01:34, Chung-Lin Tang wrote:
> Ping?
>
> On 2012/6/1 06:24 PM, Chung-Lin Tang wrote:
>> On 12/5/23 1:46 AM, Richard Henderson wrote:
>>> On 05/18/12 03:48, Chung-Lin Tang wrote:
>>>> @@ -2401,6 +2401,7 @@ scan_trace (dw_trace_info *trace)
>>>> {
>>>> /* Propagate across fallthru edges. */
>>>> dwarf2out_flush_queued_reg_saves ();
>>>> + def_cfa_1 (&this_cfa);
>>>> maybe_record_trace_start (insn, NULL);
>>>> break;
>>>> }
>>>> @@ -2455,6 +2456,18 @@ scan_trace (dw_trace_info *trace)
>>>> cur_cfa = &this_cfa;
>>>> continue;
>>>> }
>>>> + else
>>>> + {
>>>> + /* If ELT is a annulled branch-taken instruction (i.e.
>>>> executed
>>>> + only when branch is not taken), the args_size and CFA
>>>> should
>>>> + not change through the jump. */
>>>> + create_trace_edges (control);
>>>> +
>>>> + /* Update and continue with the trace. */
>>>> + add_cfi_insn = insn;
>>>> + scan_insn_after (elt);
>>>> + continue;
>>>> + }
>>>
>>> I think the def_cfa_1 is misplaced. It should be immediately before
>>> that last continue. That mirrors the sort of flow you get via the
>>> other paths through the loop.
>>
>> Or possibly moved before the dwarf2out_flush_queued_reg_saves () call in
>> the patch? (in the save_point_p () break case) Note I'm only saying
>> this based on overall ordering of those two routine calls in the loop.
>>
>> Attached is a testcase (adapted from libgomp) that, with the SH epilogue
>> unwind patch applied alone, produces the ICE I'm seeing (-O2
>> -funwind-tables).
>>
>> This dwarf2 patch, with any of the three new def_cfa_1() call sites
>> seems to solve it, though you might want to comment on which call site
>> seems "correct"
I've committed the following, after a --enable-languages=c,c++ --target=sh-elf
build and check-gcc with your patch 2/2 applied. I eyeballed the resulting
debug info and it looked correct.
Given the test case was extracted from libgomp I didn't commit that, trusting
that the real testing will continue to happen during a build.
r~
* dwarf2cfi.c (scan_trace): Handle annulled branch-taken delay slots.
diff --git a/gcc/dwarf2cfi.c b/gcc/dwarf2cfi.c
index bf2d802f..3edb6e1 100644
--- a/gcc/dwarf2cfi.c
+++ b/gcc/dwarf2cfi.c
@@ -2429,18 +2429,20 @@ scan_trace (dw_trace_info *trace)
elt = XVECEXP (pat, 0, 1);
- /* If ELT is an instruction from target of an annulled branch,
- the effects are for the target only and so the args_size
- and CFA along the current path shouldn't change. */
if (INSN_FROM_TARGET_P (elt))
{
HOST_WIDE_INT restore_args_size;
cfi_vec save_row_reg_save;
+ /* If ELT is an instruction from target of an annulled
+ branch, the effects are for the target only and so
+ the args_size and CFA along the current path
+ shouldn't change. */
add_cfi_insn = NULL;
restore_args_size = cur_trace->end_true_args_size;
cur_cfa = &cur_row->cfa;
- save_row_reg_save = VEC_copy (dw_cfi_ref, gc,
cur_row->reg_save);
+ save_row_reg_save
+ = VEC_copy (dw_cfi_ref, gc, cur_row->reg_save);
scan_insn_after (elt);
@@ -2453,8 +2455,20 @@ scan_trace (dw_trace_info *trace)
cur_row->cfa = this_cfa;
cur_row->reg_save = save_row_reg_save;
cur_cfa = &this_cfa;
- continue;
}
+ else
+ {
+ /* If ELT is a annulled branch-taken instruction (i.e.
+ executed only when branch is not taken), the args_size
+ and CFA should not change through the jump. */
+ create_trace_edges (control);
+
+ /* Update and continue with the trace. */
+ add_cfi_insn = insn;
+ scan_insn_after (elt);
+ def_cfa_1 (&this_cfa);
+ }
+ continue;
}
/* The insns in the delay slot should all be considered to happen
