Re: [doc RFA] "set debug dwarf2-read" and "set debug symtab-create"

[Doug Evans <dje@google.com>]

Hi.  "Ping." :-)

On Tue, Jun 19, 2012 at 3:26 PM, Doug Evans <dje@google.com> wrote:
> Hi.
>
> I'm committing this after a doc RFA.
> [But feel free to suggest changes or enhancements.]
>
> This adds two options for debugging dwarf2 debug info reading and symbol table
> creation, and adds the beginnings of some useful messages for such.
>
> 2012-06-19  Doug Evans  <dje@google.com>
>
>        * NEWS: Mention new options "set debug dwarf2-read" and
>        "set debug symtab-create".
>        * dwarf2read.c (dwarf2_read_debug): New static global.
>        (dwarf2_build_psymtabs_hard): Add debugging printfs.
>        (process_queue): Ditto.
>        (process_full_comp_unit): Ditto.
>        (_initialize_dwarf2_read): Add new option "set debug dwarf2-read".
>        * elfread.c (elf_symfile_read): Add debugging printf.
>        * minsyms.c (install_minimal_symbols): Ditto.
>        * psymtab.c (allocate_psymtab): Ditto.
>        * symfile.c (allocate_symtab): Ditto.
>        * symtab.c (symtab_create_debug): New global.
>        (_initialize_symtab): Add new option "set debug symtab-create".
>        * symtab.h (symtab_create_debug): Declare.
>
>        doc/
>        * gdb.texinfo (Debugging Output): Document debug options dwarf2-read
>        and symtab-create.
>
> diff --git a/gdb/NEWS b/gdb/NEWS
> index 5450939..e357599 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -462,6 +462,16 @@ tstop [NOTES]
>
>  * New options
>
> +set debug dwarf2-read
> +show debug dwarf2-read
> +  Turns on or off display of GDB info related to reading DWARF debugging
> +  information.  The default is off.
> +
> +set debug symtab-create
> +show debug symtab-create
> +  Turns on or off display of GDB debugging info related to symbol table
> +  creation.  The default is off.
> +
>  set extended-prompt
>  show extended-prompt
>   Set the GDB prompt, and allow escape sequences to be inserted to
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index a14e322..29f7257 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -21741,6 +21741,12 @@ The value is the number of nesting levels to print.
>  A value of zero turns off the display.
>  @item show debug dwarf2-die
>  Show the current state of DWARF2 DIE debugging.
> +@item set debug dwarf2-read
> +@cindex DWARF2 Reading
> +Turns on or off display of @value{GDBN} info related to reading
> +DWARF debugging information.  The default is off.
> +@item show debug dwarf2-read
> +Show the current state of DWARF2 reader debugging.
>  @item set debug displaced
>  @cindex displaced stepping debugging info
>  Turns on or off display of @value{GDBN} debugging info for the
> @@ -21838,6 +21844,12 @@ Turns on or off debugging messages for FR-V shared-library code.
>  @item show debug solib-frv
>  Display the current state of FR-V shared-library code debugging
>  messages.
> +@item set debug symtab-create
> +@cindex Symbol Table Creation
> +Turns on or off display of @value{GDBN} debugging info related to
> +symbol table creation.  The default is off.
> +@item show debug symtab-create
> +Show the current state of symbol table creation debugging.
>  @item set debug target
>  @cindex target debugging info
>  Turns on or off display of @value{GDBN} target debugging info. This info
> diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
> index 097ee7f..d128f77 100644
> --- a/gdb/dwarf2read.c
> +++ b/gdb/dwarf2read.c
> @@ -81,6 +81,10 @@
>  typedef struct symbol *symbolp;
>  DEF_VEC_P (symbolp);
>
> +/* When non-zero, print basic high level tracing messages.
> +   This is in contrast to the low level DIE reading of dwarf2_die_debug.  */
> +static int dwarf2_read_debug = 0;
> +
>  /* When non-zero, dump DIEs after they are read in.  */
>  static int dwarf2_die_debug = 0;
>
> @@ -4349,6 +4353,12 @@ dwarf2_build_psymtabs_hard (struct objfile *objfile)
>   struct obstack temp_obstack;
>   int i;
>
> +  if (dwarf2_read_debug)
> +    {
> +      fprintf_unfiltered (gdb_stdlog, "Building psymtabs of objfile %s ...\n",
> +                         objfile->name);
> +    }
> +
>   dwarf2_per_objfile->reading_partial_symbols = 1;
>
>   dwarf2_read_section (objfile, &dwarf2_per_objfile->info);
> @@ -4382,6 +4392,10 @@ dwarf2_build_psymtabs_hard (struct objfile *objfile)
>   discard_cleanups (addrmap_cleanup);
>
>   do_cleanups (back_to);
> +
> +  if (dwarf2_read_debug)
> +    fprintf_unfiltered (gdb_stdlog, "Done building psymtabs of %s\n",
> +                       objfile->name);
>  }
>
>  /* die_reader_func for load_partial_comp_unit.  */
> @@ -5286,6 +5300,13 @@ process_queue (void)
>  {
>   struct dwarf2_queue_item *item, *next_item;
>
> +  if (dwarf2_read_debug)
> +    {
> +      fprintf_unfiltered (gdb_stdlog,
> +                         "Expanding one or more symtabs of objfile %s ...\n",
> +                         dwarf2_per_objfile->objfile->name);
> +    }
> +
>   /* The queue starts out with one item, but following a DIE reference
>      may load a new CU, adding it to the end of the queue.  */
>   for (item = dwarf2_queue; item != NULL; dwarf2_queue = item = next_item)
> @@ -5301,6 +5322,12 @@ process_queue (void)
>     }
>
>   dwarf2_queue_tail = NULL;
> +
> +  if (dwarf2_read_debug)
> +    {
> +      fprintf_unfiltered (gdb_stdlog, "Done expanding symtabs of %s.\n",
> +                         dwarf2_per_objfile->objfile->name);
> +    }
>  }
>
>  /* Free all allocated queue entries.  This function only releases anything if
> @@ -5690,6 +5717,14 @@ process_full_comp_unit (struct dwarf2_per_cu_data *per_cu,
>   struct cleanup *back_to, *delayed_list_cleanup;
>   CORE_ADDR baseaddr;
>
> +  if (dwarf2_read_debug)
> +    {
> +      fprintf_unfiltered (gdb_stdlog,
> +                         "Expanding symtab of %s at offset 0x%x\n",
> +                         per_cu->is_debug_types ? "TU" : "CU",
> +                         per_cu->offset.sect_off);
> +    }
> +
>   baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
>
>   buildsym_init ();
> @@ -5765,6 +5800,14 @@ process_full_comp_unit (struct dwarf2_per_cu_data *per_cu,
>   VEC_safe_push (dwarf2_per_cu_ptr, dwarf2_per_objfile->just_read_cus, per_cu);
>
>   do_cleanups (back_to);
> +
> +  if (dwarf2_read_debug)
> +    {
> +      fprintf_unfiltered (gdb_stdlog,
> +                         "Done expanding symtab of %s at offset 0x%x\n",
> +                         per_cu->is_debug_types ? "TU" : "CU",
> +                         per_cu->offset.sect_off);
> +    }
>  }
>
>  /* Process an imported unit DIE.  */
> @@ -18077,6 +18120,15 @@ conversational style, when possible."),
>                           &set_dwarf2_cmdlist,
>                           &show_dwarf2_cmdlist);
>
> +  add_setshow_boolean_cmd ("dwarf2-read", no_class, &dwarf2_read_debug, _("\
> +Set debugging of the dwarf2 reader."), _("\
> +Show debugging of the dwarf2 reader."), _("\
> +When enabled, debugging messages are printed during dwarf2 reading\n\
> +and symtab expansion."),
> +                           NULL,
> +                           NULL,
> +                           &setdebuglist, &showdebuglist);
> +
>   add_setshow_zinteger_cmd ("dwarf2-die", no_class, &dwarf2_die_debug, _("\
>  Set debugging of the dwarf2 DIE reader."), _("\
>  Show debugging of the dwarf2 DIE reader."), _("\
> diff --git a/gdb/elfread.c b/gdb/elfread.c
> index 679d081..1edfb27 100644
> --- a/gdb/elfread.c
> +++ b/gdb/elfread.c
> @@ -1251,6 +1251,13 @@ elf_symfile_read (struct objfile *objfile, int symfile_flags)
>   asymbol **symbol_table = NULL, **dyn_symbol_table = NULL;
>   asymbol *synthsyms;
>
> +  if (symtab_create_debug)
> +    {
> +      fprintf_unfiltered (gdb_stdlog,
> +                         "Reading minimal symbols of objfile %s ...\n",
> +                         objfile->name);
> +    }
> +
>   init_minimal_symbol_collection ();
>   back_to = make_cleanup_discard_minimal_symbols ();
>
> @@ -1443,6 +1450,9 @@ elf_symfile_read (struct objfile *objfile, int symfile_flags)
>          xfree (debugfile);
>        }
>     }
> +
> +  if (symtab_create_debug)
> +    fprintf_unfiltered (gdb_stdlog, "Done reading minimal symbols.\n");
>  }
>
>  /* Callback to lazily read psymtabs.  */
> diff --git a/gdb/minsyms.c b/gdb/minsyms.c
> index d762b2d..1070fff 100644
> --- a/gdb/minsyms.c
> +++ b/gdb/minsyms.c
> @@ -1167,6 +1167,13 @@ install_minimal_symbols (struct objfile *objfile)
>
>   if (msym_count > 0)
>     {
> +      if (symtab_create_debug)
> +       {
> +         fprintf_unfiltered (gdb_stdlog,
> +                             "Installing %d minimal symbols of objfile %s.\n",
> +                             msym_count, objfile->name);
> +       }
> +
>       /* Allocate enough space in the obstack, into which we will gather the
>          bunches of new and existing minimal symbols, sort them, and then
>          compact out the duplicate entries.  Once we have a final table,
> diff --git a/gdb/psymtab.c b/gdb/psymtab.c
> index 647368c..c92cab8 100644
> --- a/gdb/psymtab.c
> +++ b/gdb/psymtab.c
> @@ -1731,6 +1731,26 @@ allocate_psymtab (const char *filename, struct objfile *objfile)
>   psymtab->next = objfile->psymtabs;
>   objfile->psymtabs = psymtab;
>
> +  if (symtab_create_debug)
> +    {
> +      /* Be a bit clever with debugging messages, and don't print objfile
> +        every time, only when it changes.  */
> +      static char *last_objfile_name = NULL;
> +
> +      if (last_objfile_name == NULL
> +         || strcmp (last_objfile_name, objfile->name) != 0)
> +       {
> +         xfree (last_objfile_name);
> +         last_objfile_name = xstrdup (objfile->name);
> +         fprintf_unfiltered (gdb_stdlog,
> +                             "Creating one or more psymtabs for objfile %s ...\n",
> +                             last_objfile_name);
> +       }
> +      fprintf_unfiltered (gdb_stdlog,
> +                         "Created psymtab 0x%lx for module %s.\n",
> +                         (long) psymtab, filename);
> +    }
> +
>   return (psymtab);
>  }
>
> diff --git a/gdb/symfile.c b/gdb/symfile.c
> index 37d98d9..01252e2 100644
> --- a/gdb/symfile.c
> +++ b/gdb/symfile.c
> @@ -2873,6 +2873,26 @@ allocate_symtab (const char *filename, struct objfile *objfile)
>   symtab->next = objfile->symtabs;
>   objfile->symtabs = symtab;
>
> +  if (symtab_create_debug)
> +    {
> +      /* Be a bit clever with debugging messages, and don't print objfile
> +        every time, only when it changes.  */
> +      static char *last_objfile_name = NULL;
> +
> +      if (last_objfile_name == NULL
> +         || strcmp (last_objfile_name, objfile->name) != 0)
> +       {
> +         xfree (last_objfile_name);
> +         last_objfile_name = xstrdup (objfile->name);
> +         fprintf_unfiltered (gdb_stdlog,
> +                             "Creating one or more symtabs for objfile %s ...\n",
> +                             last_objfile_name);
> +       }
> +      fprintf_unfiltered (gdb_stdlog,
> +                         "Created symtab 0x%lx for module %s.\n",
> +                         (long) symtab, filename);
> +    }
> +
>   return (symtab);
>  }
>
> diff --git a/gdb/symtab.c b/gdb/symtab.c
> index 215c53d..ee37f30 100644
> --- a/gdb/symtab.c
> +++ b/gdb/symtab.c
> @@ -109,6 +109,9 @@ void _initialize_symtab (void);
>
>  /* */
>
> +/* When non-zero, print debugging messages related to symtab creation.  */
> +int symtab_create_debug = 0;
> +
>  /* Non-zero if a file may be known by two different basenames.
>    This is the uncommon case, and significantly slows down gdb.
>    Default set to "off" to not slow down the common case.  */
> @@ -5014,5 +5017,13 @@ one base name, and gdb will do file name comparisons more efficiently."),
>                           NULL, NULL,
>                           &setlist, &showlist);
>
> +  add_setshow_boolean_cmd ("symtab-create", no_class, &symtab_create_debug,
> +                          _("Set debugging of symbol table creation."),
> +                          _("Show debugging of symbol table creation."), _("\
> +When enabled, debugging messages are printed when building symbol tables."),
> +                           NULL,
> +                           NULL,
> +                           &setdebuglist, &showdebuglist);
> +
>   observer_attach_executable_changed (symtab_observer_executable_changed);
>  }
> diff --git a/gdb/symtab.h b/gdb/symtab.h
> index 8ee187e..57f618d 100644
> --- a/gdb/symtab.h
> +++ b/gdb/symtab.h
> @@ -1250,6 +1250,8 @@ void fixup_section (struct general_symbol_info *ginfo,
>
>  struct objfile *lookup_objfile_from_block (const struct block *block);
>
> +extern int symtab_create_debug;
> +
>  extern int basenames_may_differ;
>
>  int compare_filenames_for_search (const char *filename,