Re: [PATCH][debug] Add debug and earlydebug dumps

[Richard Biener <rguenther at suse dot de>]

On Mon, 13 Aug 2018, Tom de Vries wrote:

> Hi,
> 
> With the introduction of early debug, we've added a phase in the compiler which
> produces information which is not visible, unless we run the compiler in the
> debugger and call debug_dwarf from dwarf2out_early_finish or some such.
> 
> This patch adds dumping of "early" and "final" debug info, into .earlydebug
> and .debug dump files, such that we can follow f.i. the upper bound of a vla
> type from early debug:
> ...
>           DW_AT_upper_bound: location descriptor:
>             (0x7f0d645b7550) DW_OP_GNU_variable_value , 0
> ...
> to final debug:
> ...
>           DW_AT_upper_bound: location descriptor:
>             (0x7f0d645b7550) DW_OP_fbreg 18446744073709551592, 0
>             (0x7f0d645b7a00) DW_OP_deref 8, 0
> ...
> to -dA annotated assembly file:
> ...
>         .uleb128 0x3    # DW_AT_upper_bound
>         .byte   0x91    # DW_OP_fbreg
>         .sleb128 -24
>         .byte   0x6     # DW_OP_deref
> ...
> 
> The .debug file shows the same information as the annotated assembly, but in
> the same format as the "early" debug info.
> 
> Bootstrapped and reg-tested on x86_64.
> 
> OK for trunk?

OK.  Can you document the options to trigger those dumps?
I suppose -fdump-tree-earlydebug and -fdump-tree-debug?

Thanks,
Richard.

> Thanks,
> - Tom
> 
> [debug] Add debug and earlydebug dumps
> 
> 2018-08-13  Tom de Vries  <tdevries@suse.de>
> 
> 	* cgraph.h (debuginfo_early_init, debuginfo_init, debuginfo_fini)
> 	(debuginfo_start, debuginfo_stop, debuginfo_early_start)
> 	(debuginfo_early_stop): Declare.
> 	* cgraphunit.c (debuginfo_early_init, debuginfo_init, debuginfo_fini)
> 	(debuginfo_start, debuginfo_stop, debuginfo_early_start)
> 	(debuginfo_early_stop): New function.
> 	(symbol_table::finalize_compilation_unit): Call debuginfo_early_start
> 	and debuginfo_early_stop.
> 	* dwarf2out.c (print_dw_val, print_loc_descr, print_die): Handle
> 	flag_dump_noaddr and flag_dump_unnumbered.
> 	(dwarf2out_finish, dwarf2out_early_finish): Dump dwarf.
> 	* toplev.c (compile_file): Call debuginfo_start and debuginfo_stop.
> 	(general_init): Call debuginfo_early_init.
> 	(finalize): Call debuginfo_fini.
> 	(do_compile): Call debuginfo_init.
> 
> 	* lto.c (lto_main):  Call debuginfo_early_start and
> 	debuginfo_early_stop.
> 
> 	* gcc.c-torture/unsorted/dump-noaddr.x: Skip earlydebug and debug dumps.
> 
> ---
>  gcc/cgraph.h                                       |  8 +++
>  gcc/cgraphunit.c                                   | 66 ++++++++++++++++++++++
>  gcc/dwarf2out.c                                    | 46 ++++++++++++---
>  gcc/lto/lto.c                                      |  2 +
>  gcc/testsuite/gcc.c-torture/unsorted/dump-noaddr.x |  7 +++
>  gcc/toplev.c                                       |  5 ++
>  6 files changed, 126 insertions(+), 8 deletions(-)
> 
> diff --git a/gcc/cgraph.h b/gcc/cgraph.h
> index a8b1b4cb3c3..2b00f0165fa 100644
> --- a/gcc/cgraph.h
> +++ b/gcc/cgraph.h
> @@ -25,6 +25,14 @@ along with GCC; see the file COPYING3.  If not see
>  #include "ipa-ref.h"
>  #include "plugin-api.h"
>  
> +extern void debuginfo_early_init (void);
> +extern void debuginfo_init (void);
> +extern void debuginfo_fini (void);
> +extern void debuginfo_start (void);
> +extern void debuginfo_stop (void);
> +extern void debuginfo_early_start (void);
> +extern void debuginfo_early_stop (void);
> +
>  class ipa_opt_pass_d;
>  typedef ipa_opt_pass_d *ipa_opt_pass;
>  
> diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
> index 462e247328e..6649942c4fb 100644
> --- a/gcc/cgraphunit.c
> +++ b/gcc/cgraphunit.c
> @@ -2636,6 +2636,70 @@ symbol_table::compile (void)
>      }
>  }
>  
> +static int debuginfo_early_dump_nr;
> +static FILE *debuginfo_early_dump_file;
> +static dump_flags_t debuginfo_early_dump_flags;
> +
> +static int debuginfo_dump_nr;
> +static FILE *debuginfo_dump_file;
> +static dump_flags_t debuginfo_dump_flags;
> +
> +void
> +debuginfo_early_init (void)
> +{
> +  gcc::dump_manager *dumps = g->get_dumps ();
> +  debuginfo_early_dump_nr = dumps->dump_register (".earlydebug", "earlydebug",
> +						  "earlydebug", DK_tree,
> +						  OPTGROUP_NONE,
> +						  false);
> +  debuginfo_dump_nr = dumps->dump_register (".debug", "debug",
> +					     "debug", DK_tree,
> +					     OPTGROUP_NONE,
> +					     false);
> +}
> +
> +void
> +debuginfo_init (void)
> +{
> +  gcc::dump_manager *dumps = g->get_dumps ();
> +  debuginfo_dump_file = dump_begin (debuginfo_dump_nr, NULL);
> +  debuginfo_dump_flags = dumps->get_dump_file_info (debuginfo_dump_nr)->pflags;
> +  debuginfo_early_dump_file = dump_begin (debuginfo_early_dump_nr, NULL);
> +  debuginfo_early_dump_flags = dumps->get_dump_file_info (debuginfo_early_dump_nr)->pflags;
> +}
> +
> +void
> +debuginfo_fini (void)
> +{
> +  if (debuginfo_dump_file)
> +    dump_end (debuginfo_dump_nr, debuginfo_dump_file);
> +  if (debuginfo_early_dump_file)
> +    dump_end (debuginfo_early_dump_nr, debuginfo_early_dump_file);
> +}
> +
> +void
> +debuginfo_start (void)
> +{
> +  set_dump_file (debuginfo_dump_file);
> +}
> +
> +void
> +debuginfo_stop (void)
> +{
> +  set_dump_file (NULL);
> +}
> +
> +void
> +debuginfo_early_start (void)
> +{
> +  set_dump_file (debuginfo_early_dump_file);
> +}
> +
> +void
> +debuginfo_early_stop (void)
> +{
> +  set_dump_file (NULL);
> +}
>  
>  /* Analyze the whole compilation unit once it is parsed completely.  */
>  
> @@ -2691,7 +2755,9 @@ symbol_table::finalize_compilation_unit (void)
>  
>        /* Clean up anything that needs cleaning up after initial debug
>  	 generation.  */
> +      debuginfo_early_start ();
>        (*debug_hooks->early_finish) (main_input_filename);
> +      debuginfo_early_stop ();
>      }
>  
>    /* Finally drive the pass manager.  */
> diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
> index 9ed473088e7..4b63cbd8a1e 100644
> --- a/gcc/dwarf2out.c
> +++ b/gcc/dwarf2out.c
> @@ -6455,7 +6455,12 @@ print_dw_val (dw_val_node *val, bool recurse, FILE *outfile)
>  	  print_indent -= 4;
>  	}
>        else
> -	fprintf (outfile, " (%p)\n", (void *) val->v.val_loc);
> +	{
> +	  if (flag_dump_noaddr || flag_dump_unnumbered)
> +	    fprintf (outfile, " #\n");
> +	  else
> +	    fprintf (outfile, " (%p)\n", (void *) val->v.val_loc);
> +	}
>        break;
>      case dw_val_class_loc_list:
>        fprintf (outfile, "location list -> label:%s",
> @@ -6524,7 +6529,10 @@ print_dw_val (dw_val_node *val, bool recurse, FILE *outfile)
>  	    }
>  	  else
>  	    fprintf (outfile, "die -> %ld", die->die_offset);
> -	  fprintf (outfile, " (%p)", (void *) die);
> +	  if (flag_dump_noaddr || flag_dump_unnumbered)
> +	    fprintf (outfile, " #");
> +	  else
> +	    fprintf (outfile, " (%p)", (void *) die);
>  	}
>        else
>  	fprintf (outfile, "die -> <null>");
> @@ -6614,8 +6622,11 @@ print_loc_descr (dw_loc_descr_ref loc, FILE *outfile)
>    for (l = loc; l != NULL; l = l->dw_loc_next)
>      {
>        print_spaces (outfile);
> -      fprintf (outfile, "(%p) %s",
> -	       (void *) l,
> +      if (flag_dump_noaddr || flag_dump_unnumbered)
> +	fprintf (outfile, "#");
> +      else
> +	fprintf (outfile, "(%p)", (void *) l);
> +      fprintf (outfile, " %s",
>  	       dwarf_stack_op_name (l->dw_loc_opc));
>        if (l->dw_loc_oprnd1.val_class != dw_val_class_none)
>  	{
> @@ -6642,9 +6653,12 @@ print_die (dw_die_ref die, FILE *outfile)
>    unsigned ix;
>  
>    print_spaces (outfile);
> -  fprintf (outfile, "DIE %4ld: %s (%p)\n",
> -	   die->die_offset, dwarf_tag_name (die->die_tag),
> -	   (void*) die);
> +  fprintf (outfile, "DIE %4ld: %s ",
> +	   die->die_offset, dwarf_tag_name (die->die_tag));
> +  if (flag_dump_noaddr || flag_dump_unnumbered)
> +    fprintf (outfile, "#\n");
> +  else
> +    fprintf (outfile, "(%p)\n", (void*) die);
>    print_spaces (outfile);
>    fprintf (outfile, "  abbrev id: %lu", die->die_abbrev);
>    fprintf (outfile, " offset: %ld", die->die_offset);
> @@ -31088,7 +31102,7 @@ reset_dies (dw_die_ref die)
>     and generate the DWARF-2 debugging info.  */
>  
>  static void
> -dwarf2out_finish (const char *)
> +dwarf2out_finish (const char *filename)
>  {
>    comdat_type_node *ctnode;
>    dw_die_ref main_comp_unit_die;
> @@ -31169,6 +31183,12 @@ dwarf2out_finish (const char *)
>    resolve_addr (comp_unit_die ());
>    move_marked_base_types ();
>  
> +  if (dump_file)
> +    {
> +      fprintf (dump_file, "DWARF for %s\n", filename);
> +      print_die (comp_unit_die (), dump_file);
> +    }
> +
>    /* Initialize sections and labels used for actual assembler output.  */
>    unsigned generation = init_sections_and_labels (false);
>  
> @@ -31864,6 +31884,11 @@ dwarf2out_early_finish (const char *filename)
>    if (in_lto_p)
>      {
>        early_dwarf_finished = true;
> +      if (dump_file)
> +	{
> +	  fprintf (dump_file, "LTO EARLY DWARF for %s\n", filename);
> +	  print_die (comp_unit_die (), dump_file);
> +	}
>        return;
>      }
>  
> @@ -31941,6 +31966,11 @@ dwarf2out_early_finish (const char *filename)
>  
>    /* The early debug phase is now finished.  */
>    early_dwarf_finished = true;
> +  if (dump_file)
> +    {
> +      fprintf (dump_file, "EARLY DWARF for %s\n", filename);
> +      print_die (comp_unit_die (), dump_file);
> +    }
>  
>    /* Do not generate DWARF assembler now when not producing LTO bytecode.  */
>    if ((!flag_generate_lto && !flag_generate_offload)
> diff --git a/gcc/lto/lto.c b/gcc/lto/lto.c
> index 8db280ecefc..10618896022 100644
> --- a/gcc/lto/lto.c
> +++ b/gcc/lto/lto.c
> @@ -3419,7 +3419,9 @@ lto_main (void)
>  	    lto_promote_statics_nonwpa ();
>  
>  	  /* Annotate the CU DIE and mark the early debug phase as finished.  */
> +	  debuginfo_early_start ();
>  	  debug_hooks->early_finish ("<artificial>");
> +	  debuginfo_early_stop ();
>  
>  	  /* Let the middle end know that we have read and merged all of
>  	     the input files.  */ 
> diff --git a/gcc/testsuite/gcc.c-torture/unsorted/dump-noaddr.x b/gcc/testsuite/gcc.c-torture/unsorted/dump-noaddr.x
> index e86f36a1861..d2be9c001e0 100644
> --- a/gcc/testsuite/gcc.c-torture/unsorted/dump-noaddr.x
> +++ b/gcc/testsuite/gcc.c-torture/unsorted/dump-noaddr.x
> @@ -19,6 +19,13 @@ proc dump_compare { src options } {
>  	    set dump2 "$tmpdir/dump2/[file tail $dump1]"
>  	    set dumptail "gcc.c-torture/unsorted/[file tail $dump1]"
>  	    regsub {\.\d+((t|r|i)\.[^.]+)$} $dumptail {.*\1} dumptail
> +	    if { "$dumptail" == "gcc.c-torture/unsorted/dump-noaddr.c.*t.earlydebug" 
> +		 || "$dumptail" == "gcc.c-torture/unsorted/dump-noaddr.c.*t.debug" } {
> +		# The DW_AT_producer line contains the command line options so, this will
> +		# fail on dump1 having '--param ggc-min-heapsize=1', and dump2 not.
> +		untested "$dumptail, $option comparison"
> +		continue
> +	    }
>  	    set tmp [ diff "$dump1" "$dump2" ]
>  	    if { $tmp == 0 } {
>  		untested "$dumptail, $option comparison"
> diff --git a/gcc/toplev.c b/gcc/toplev.c
> index aa943a8655e..d28bff01552 100644
> --- a/gcc/toplev.c
> +++ b/gcc/toplev.c
> @@ -529,7 +529,9 @@ compile_file (void)
>        dwarf2out_frame_finish ();
>  #endif
>  
> +      debuginfo_start ();
>        (*debug_hooks->finish) (main_input_filename);
> +      debuginfo_stop ();
>        timevar_pop (TV_SYMOUT);
>  
>        /* Output some stuff at end of file if nec.  */
> @@ -1185,6 +1187,7 @@ general_init (const char *argv0, bool init_signals)
>    symtab = new (ggc_cleared_alloc <symbol_table> ()) symbol_table ();
>  
>    statistics_early_init ();
> +  debuginfo_early_init ();
>    finish_params ();
>  }
>  
> @@ -2079,6 +2082,7 @@ finalize (bool no_backend)
>    if (!no_backend)
>      {
>        statistics_fini ();
> +      debuginfo_fini ();
>  
>        g->get_passes ()->finish_optimization_passes ();
>  
> @@ -2156,6 +2160,7 @@ do_compile ()
>            init_final (main_input_filename);
>            coverage_init (aux_base_name);
>            statistics_init ();
> +	  debuginfo_init ();
>            invoke_plugin_callbacks (PLUGIN_START_UNIT, NULL);
>  
>            timevar_stop (TV_PHASE_SETUP);
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)