Re: [PING] [PATCH] Fix backtrace limit stopping on inline frame

[Hannes Domani <ssbssa@yahoo.de>]

 Ping.


Am Mittwoch, 17. Januar 2024, 17:06:12 MEZ hat Hannes Domani <ssbssa@yahoo.de> Folgendes geschrieben:

> Ping.
>
>
> On 06.01.2024 15:17, Hannes Domani wrote:
> > If you have set up a backtrace limit, and the backtrace stops
> > because of this in an inline frame with arguments, you get an
> > assertion failure:
> > ```
> > (gdb) bt
> > #0  normal_frame (i=0) at gdb-29865.c:4
> > #1  0x000000013fe3162a in inline_frame (i=0) at gdb-29865.c:9
> > #2  main () at gdb-29865.c:14
> > (gdb) set backtrace limit 2
> > (gdb) bt
> > #0  normal_frame (i=0) at gdb-29865.c:4
> > #1  0x000000013fe3162a in inline_frame (
> > C:/src/repos/binutils-gdb.git/gdb/frame.c:3346: internal-error: reinflate: Assertion `m_cached_level >= -1' failed.
> > ```
> >
> > And if this one if fixed, there is another one as well:
> > ```
> > (gdb) bt
> > #0  normal_frame (i=0) at gdb-29865.c:4
> > #1  0x000000013fdf162a in inline_frame (
> > C:/src/repos/binutils-gdb.git/gdb/dwarf2/loc.c:1160: internal-error: dwarf_expr_reg_to_entry_parameter: Assertion `frame != NULL' failed.
> > ```
> >
> > The reason for both of them is this kind of loop:
> > ```
> >    while (get_frame_type (frame) == INLINE_FRAME)
> >      frame = get_prev_frame (frame);
> > ```
> > Since get_prev_frame respects the backtrace limit, it will return
> > NULL, and from there on you can't continue.
> > This changes these loops to use get_prev_frame_always instead, so
> > you always get a non-inline frame in the end.
> >
> > With this backtrace works:
> > ```
> > (gdb) bt
> > #0  normal_frame (i=0) at gdb-29865.c:4
> > #1  0x000000013fd4162a in inline_frame (i=0) at gdb-29865.c:9
> > (gdb)
> > ```
> >
> > Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29865
> > ---
> >  gdb/dwarf2/frame.c                  | 2 +-
> >  gdb/dwarf2/loc.c                    | 2 +-
> >  gdb/testsuite/gdb.opt/inline-bt.c  | 8 ++++----
> >  gdb/testsuite/gdb.opt/inline-bt.exp | 1 +
> >  4 files changed, 7 insertions(+), 6 deletions(-)
> >
> > diff --git a/gdb/dwarf2/frame.c b/gdb/dwarf2/frame.c
> > index d3d1ecdf1f5..143b934e5ef 100644
> > --- a/gdb/dwarf2/frame.c
> > +++ b/gdb/dwarf2/frame.c
> > @@ -1423,7 +1423,7 @@ dwarf2_frame_cfa (frame_info_ptr this_frame)
> >          _("cfa not available for record btrace target"));
> >
> >    while (get_frame_type (this_frame) == INLINE_FRAME)
> > -    this_frame = get_prev_frame (this_frame);
> > +    this_frame = get_prev_frame_always (this_frame);
> >    if (get_frame_unwind_stop_reason (this_frame) == UNWIND_UNAVAILABLE)
> >      throw_error (NOT_AVAILABLE_ERROR,
> >          _("can't compute CFA for this frame: "
> > diff --git a/gdb/dwarf2/loc.c b/gdb/dwarf2/loc.c
> > index c15221eb7a2..b1f188bf9c5 100644
> > --- a/gdb/dwarf2/loc.c
> > +++ b/gdb/dwarf2/loc.c
> > @@ -1156,7 +1156,7 @@ dwarf_expr_reg_to_entry_parameter (frame_info_ptr frame,
> >
> >    while (get_frame_type (frame) == INLINE_FRAME)
> >      {
> > -      frame = get_prev_frame (frame);
> > +      frame = get_prev_frame_always (frame);
> >        gdb_assert (frame != NULL);
> >      }
> >
> > diff --git a/gdb/testsuite/gdb.opt/inline-bt.c b/gdb/testsuite/gdb.opt/inline-bt.c
> > index 8dac8d30300..0dad0f47e6e 100644
> > --- a/gdb/testsuite/gdb.opt/inline-bt.c
> > +++ b/gdb/testsuite/gdb.opt/inline-bt.c
> > @@ -28,15 +28,15 @@ volatile int result;
> >
> >  void bar(void);
> >
> > -inline ATTR int func1(void)
> > +inline ATTR int func1(int s)
> >  {
> >    bar ();
> > -  return x * y;
> > +  return x * y + s;
> >  }
> >
> >  inline ATTR int func2(void)
> >  {
> > -  return x * func1 ();
> > +  return x * func1 (1);
> >  }
> >
> >  int main (void)
> > @@ -47,7 +47,7 @@ int main (void)
> >    y = 8;
> >    bar ();
> >
> > -  val = func1 ();
> > +  val = func1 (2);
> >    result = val;
> >
> >    val = func2 ();
> > diff --git a/gdb/testsuite/gdb.opt/inline-bt.exp b/gdb/testsuite/gdb.opt/inline-bt.exp
> > index 501b24109e3..b0e5f61a5c7 100644
> > --- a/gdb/testsuite/gdb.opt/inline-bt.exp
> > +++ b/gdb/testsuite/gdb.opt/inline-bt.exp
> > @@ -65,3 +65,4 @@ gdb_test "up" "#1  .*func1.*" "up from bar (4)"
> >  gdb_test "info frame" ".*in func1.*" "info frame still works"
> >  # Verify the user visible limit works as expected.
> >  gdb_test "up" "Initial frame selected; you cannot go up." "up hits limit"
> > +gdb_test "backtrace" "#0  bar.*#1  .*func1.*" "backtrace hits limit"