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

[Doug Evans <dje at google dot 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,