RE: [PATCH v4 13/13] gdb, mi: Add -shadow-stack-list-frames command

["Joos, Christina" <christina.joos@intel.com>]

> -----Original Message-----
> From: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
> Sent: Donnerstag, 3. September 2026 10:11
> To: Joos, Christina <christina.joos@intel.com>
> Cc: gdb-patches@sourceware.org; tom@tromey.com
> Subject: Re: [PATCH v4 13/13] gdb, mi: Add -shadow-stack-list-frames
> command
> 
> Christina Schimpe <christina.schimpe@intel.com> writes:
> 
> > Add the mi command for the command "backtrace -shadow".
> > Similar to the mi interface for the ordinary backtrace command,
> > support low-frame and high-frame as command line parameters.
> >
> > Example print of a full shadow stack backtrace:
> > ~~~
> > (gdb)
> > -shadow-stack-list-frames
> > ^done,shadow-stack=[
> > shadow-stack-frame={level="0",addr="0x00007ffff7c3fe70",
> >   func="__libc_start_call_main",file="../sysdeps/nptl/libc_start_call_main.h",
> >   fullname="/usr/[...]/sysdeps/nptl/libc_start_call_main.h",
> >   line="58",arch="i386:x86-64"},
> > shadow-stack-frame={level="1",addr="0x00007ffff7c3ff20",
> >   func="__libc_start_main_impl",file="../csu/libc-start.c",
> >   fullname="/usr/[...]/csu/libc-start.c",
> >   line="128",arch="i386:x86-64"},
> > shadow-stack-frame={level="2",addr="0x0000000000401075",
> >   func="_start",arch="i386:x86-64"}]
> > ~~~
> >
> > Example print of a shadow stack backtrace using low- and high-frame:
> > ~~~
> > (gdb)
> > -shadow-stack-list-frames 0 1
> > ^done,shadow-stack=[
> > shadow-stack-frame={level="0",addr="0x00007ffff7c3fe70",
> >   func="__libc_start_call_main",file="../sysdeps/nptl/libc_start_call_main.h",
> >   fullname="/usr/[...]/sysdeps/nptl/libc_start_call_main.h",
> >   line="58",arch="i386:x86-64"},
> > shadow-stack-frame={level="1",addr="0x00007ffff7c3ff20",
> >   func="__libc_start_main_impl",file="../csu/libc-start.c",
> >   fullname="/usr/[...]/csu/libc-start.c",
> >   line="128",arch="i386:x86-64"}]
> > ~~~
> > ---
> >  gdb/NEWS                                      |   8 ++
> >  gdb/doc/gdb.texinfo                           |  51 ++++++++
> >  gdb/mi/mi-cmd-stack.c                         | 100 +++++++++++++++
> >  gdb/mi/mi-cmds.c                              |   2 +
> >  gdb/mi/mi-cmds.h                              |   1 +
> >  gdb/shadow-stack.c                            | 121 ++++++++++++------
> >  gdb/shadow-stack.h                            |  40 ++++++
> >  .../gdb.mi/mi-shadow-stack-signal.exp         |  69 ++++++++++
> >  gdb/testsuite/gdb.mi/mi-shadow-stack.exp      |  93 ++++++++++++++
> >  9 files changed, 449 insertions(+), 36 deletions(-)  create mode
> > 100644 gdb/testsuite/gdb.mi/mi-shadow-stack-signal.exp
> >  create mode 100644 gdb/testsuite/gdb.mi/mi-shadow-stack.exp
> 
> I don't have much experience with MI, so I'll only comment on the translation
> strings. Though to be honest in all this time AFAICT GDB hasn't ever been
> translated so I wonder how useful it is to pay attention to this.

I don't know how often or if that happens, too....
But since I use the interface, I should probably better use it correctly. 😉 

> > +/* Parse arguments of -shadow-stack-list-frames command and set
> FRAME_LOW
> > +   and FRAME_HIGH accordingly.  Throw an error in case the arguments are
> > +   invalid.  */
> > +static void
> > +mi_cmd_shadow_stack_list_frames_parse_args (const char *const *argv,
> > +					    int argc, int &frame_low,
> > +					    int &frame_high)
> > +{
> > +  const std::string mi_cmd_name = "-shadow-stack-list-frames";
> > +  /* There should either be low - high range, or no arguments.  */
> > +  if ((argc != 0) && (argc != 2))
> > +    error (_("%s: Usage: [FRAME_LOW FRAME_HIGH]"), mi_cmd_name.c_str
> > +());
> > +
> > +  /* If there is a range, set it.  */
> > +  if (argc == 2)
> > +    {
> > +      frame_low = atoi (argv[0]);
> > +      frame_high = atoi (argv[1]);
> > +      std::string err_str;
> > +      if (frame_low < 0)
> > +	{
> > +	  err_str = "``" + std::to_string (frame_low) + "''";
> > +	  if (frame_high < 0)
> > +	    err_str += " and ``" + std::to_string (frame_high) + "''";
> > +	}
> > +      else if (frame_high < 0)
> > +	err_str = "``" + std::to_string (frame_high) + "''";
> > +
> > +      if (!err_str.empty ())
> > +	{
> > +	  err_str = mi_cmd_name + ": Invalid option " + err_str + ".";
> > +	  error (_("%s"), err_str.c_str ());
> 
> Passing "%s" as a string to be translated doesn't work. gettext extracts the
> translatable strings by scanning the source code at build time, it's not done at
> runtime.
> 
> You can see this if you run this in the GDB build directory:
> 
> $ make -C gdb gdb.pot
> 
> Then you'll see in $build_dir/gdb/po/gdb.pot:
> 
> #: compile/compile.c:112 cp-namespace.c:528 dwarf2/read.c:1021
> #: dwarf2/read.c:1030 mi/mi-cmd-stack.c:802 shadow-stack.c:632
> #: shadow-stack.c:649 utils.c:657 read.c:1021 read.c:1030 mi-cmd-stack.c:802
> #: compile.c:112
> #, possible-c-format
> msgid "%s"
> msgstr ""
> 
> Which isn't very translatable. The only string containing "Invalid option" in
> gdb.pot is from mi-cmd-var.c, unrelated to this code.

Ah thanks a lot for pointing this out, I was not aware ! Will fix this.

I think there are some more occurrences in this series which I will double check.
There is one, for instance, in shadow-stack.c:

~~~
      error (_("Cannot print shadow stack backtrace: %s.\n"),
	     ssp_unwind_stop_reason_to_err_string (reason));
~~~

But in this case REASON is more like an error code, so I believe it doesn't have to
be translated.

> > +	}
> > +    }
> > +  else
> > +    {
> > +      /* No arguments, print the whole shadow stack backtrace.  */
> > +      frame_low = -1;
> > +      frame_high = -1;
> > +    }
> > +}
> 
> ⋮
> 
> > +CORE_ADDR
> > +get_validated_shadow_stack_pointer (gdbarch *gdbarch)
> >  {
> >    if (!target_has_stack ())
> > -    error (_("No shadow stack."));
> > +    {
> > +      if (!current_uiout->is_mi_like_p ())
> > +	error (_("No shadow stack."));
> > +      else
> > +	error (_("-shadow-stack-list-frames: No shadow stack."));
> > +    }
> >
> > -  gdbarch *gdbarch = get_current_arch ();
> >    if (!gdbarch_address_in_shadow_stack_memory_range_p (gdbarch)
> >        || !gdbarch_top_addr_empty_shadow_stack_p (gdbarch)
> >        || gdbarch_ssp_regnum (gdbarch) == -1)
> > -    error (_("Printing of the shadow stack backtrace is not supported for"
> > -	     " the current target."));
> > +    {
> > +      std::string err_str = "Printing of the shadow stack backtrace";
> > +      err_str += " is not supported for the current target.";
> > +      if (!current_uiout->is_mi_like_p ())
> > +	error (_("%s"), err_str.c_str());
> > +      else
> > +	error (_("-shadow-stack-list-frames: %s"), err_str.c_str());
> 
> Same problem in the two _() calls above, and the two below.

Yes, will fix.

> > +    }
> >
> >    regcache *regcache = get_thread_regcache (inferior_thread ());
> >    bool shadow_stack_enabled = false;
> > @@ -621,10 +642,25 @@ backtrace_shadow_command (const
> frame_print_options &fp_opts,
> >  					shadow_stack_enabled);
> >
> >    if (!start_ssp.has_value () || !shadow_stack_enabled)
> > -    error (_("Shadow stack is not enabled for the current thread."));
> > +    {
> > +      std::string err_str
> > +	= "Shadow stack is not enabled for the current thread.";
> > +      if (!current_uiout->is_mi_like_p ())
> > +	error (_("%s"), err_str.c_str());
> > +      else
> > +	error (_("-shadow-stack-list-frames: %s"), err_str.c_str());
> > +    }
> >
> > -  /* Check if START_SSP points to a shadow stack memory range and use
> > -     the returned range to determine when to stop unwinding.
> > +  return *start_ssp;
> > +}

Thanks!
Christina
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