Re: [PATCH 4/6] DWARF Two Level Line Tables: lnp_state_machine, lnp_reader_state

[Simon Marchi <simon.marchi@ericsson.com>]

On 15-05-27 06:21 PM, Doug Evans wrote:
> Doug Evans writes:
>   > Hi.
>   >
>   > This patch puts the line number state machine into a struct
>   > to make it clear exactly what is part of the state machine
>   > and what is not. Previously, gdb just had a bunch of local variables.
>   >
>   > 2015-03-12  Doug Evans  <dje@google.com>
>   >
>   > 	* dwarf2read.c (lnp_state_machine): New typedef.
>   > 	(lnp_reader_state): New typedef.
>   > 	(dwarf_record_line_1): Renamed from dwarf_record_line.
>   > 	All callers updated.
>   > 	(dwarf_record_line): New function.
>   > 	(init_lnp_state_machine): New function.
>   > 	(check_line_address): Replace p_record_line parameter with state.
>   > 	All callers updated.
>   > 	(dwarf_decode_lines_1): Call dwarf_record_line, init_lnp_state_machine.
>   > 	Update to record state in lnp_state_machine.
> 
> Here is what I committed.
> Just a few comment changes to remove references to two level
> line tables, which are in a later patch.

Hi Doug,

I have a little question about something this patch. One behaviour changed,
but I don't know if it was intentional or not. I assume it is not, since the goal
of this patch was to refactor/cleanup.

When reading full symbols, after an end_sequence, dwarf_finish_line was called
unconditionally. Now, the call to dwarf_finish_line is guarded by:

    if (state->last_subfile != current_subfile) {

Before this patch, the two other calls to dwarf_finish_line were guarded by this if.
However, the third one wasn't. Is this change intentional?

I am asking this because that call is apparently important for gdb to properly
understand DWARF generated by one of our internal compiler. To restore the previous
behaviour, I did the following. Would it make sense to have the same change in FSF's gdb?

---8<---

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 1e290c3..d79b2e3 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -17658,7 +17658,7 @@ dwarf_record_line (lnp_reader_state *reader, lnp_state_machine *state,
       lh->file_names[file - 1].included_p = 1;
       if (reader->record_lines_p && is_stmt)
        {
-         if (state->last_subfile != current_subfile)
+         if (state->last_subfile != current_subfile || end_sequence)
            {
              dwarf_finish_line (reader->gdbarch, state->last_subfile,
                                 state->address, state->record_line);

--->8---