gdb/dwarf: dump cooked index contents in cooked_index_functions::dump

  From: Simon Marchi <simon.marchi@efficios.com>

As I am investigating a crash I see with the cooked index, I thought it
would be useful to have a way to dump the index contents.  For those not
too familiar with it (that includes me), it can help get a feel of what
it contains and how it is structured.

The cooked_index_functions::dump function is called as part of the
"maintenance print objfiles" command.  I tried to make the output
well structured and indented to help readability, as this prints a lot
of text.

The dump function first dumps all cooked index entries, like this:

    [25] ((cooked_index_entry *) 0x621000121220)
    name:       __ioinit
    canonical:  __ioinit
    DWARF tag:  DW_TAG_variable
    flags:      0x2 [IS_STATIC]
    DIE offset: 0x21a4
    parent:     ((cooked_index_entry *) 0x6210000f9610) [std]

Then the information about the main symbol:

    main: ((cooked_index_entry *) 0x621000123b40) [main]

And finally the address map contents:

    [1] ((addrmap *) 0x6210000f7910)

      [0x0] ((dwarf2_per_cu_data *) 0)
      [0x118a] ((dwarf2_per_cu_data *) 0x60c000007f00)
      [0x1cc7] ((dwarf2_per_cu_data *) 0)
      [0x1cc8] ((dwarf2_per_cu_data *) 0x60c000007f00)
      [0x1cdf] ((dwarf2_per_cu_data *) 0)
      [0x1ce0] ((dwarf2_per_cu_data *) 0x60c000007f00)

The display of address maps above could probably be improved, to show it
more as ranges, but I think this is a reasonable start.

Note that this patch depends on Pedro Alves' patch "enum_flags
to_string" [1].  If my patch is to be merged before Pedro's series, I
will cherry-pick this patch from his series and merge it before mine.

[1] https://inbox.sourceware.org/gdb-patches/20221212203101.1034916-8-pedro@palves.net/

Change-Id: Ida13e479fd4c8d21102ddd732241778bc3b6904a
---
 gdb/dwarf2/cooked-index.c | 16 +++++++++
 gdb/dwarf2/cooked-index.h |  4 +++
 gdb/dwarf2/read.c         | 74 ++++++++++++++++++++++++++++++++++++++-
 3 files changed, 93 insertions(+), 1 deletion(-)


base-commit: 48afe8b710712bf131fadbfa3278e512a7034483
  

Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:

> From: Simon Marchi <simon.marchi@efficios.com>
>
> As I am investigating a crash I see with the cooked index, I thought it
> would be useful to have a way to dump the index contents.  For those not
> too familiar with it (that includes me), it can help get a feel of what
> it contains and how it is structured.
>
> The cooked_index_functions::dump function is called as part of the
> "maintenance print objfiles" command.  I tried to make the output
> well structured and indented to help readability, as this prints a lot
> of text.
>
> The dump function first dumps all cooked index entries, like this:
>
>     [25] ((cooked_index_entry *) 0x621000121220)
>     name:       __ioinit
>     canonical:  __ioinit
>     DWARF tag:  DW_TAG_variable
>     flags:      0x2 [IS_STATIC]
>     DIE offset: 0x21a4
>     parent:     ((cooked_index_entry *) 0x6210000f9610) [std]
>
> Then the information about the main symbol:
>
>     main: ((cooked_index_entry *) 0x621000123b40) [main]
>
> And finally the address map contents:
>
>     [1] ((addrmap *) 0x6210000f7910)
>
>       [0x0] ((dwarf2_per_cu_data *) 0)
>       [0x118a] ((dwarf2_per_cu_data *) 0x60c000007f00)
>       [0x1cc7] ((dwarf2_per_cu_data *) 0)
>       [0x1cc8] ((dwarf2_per_cu_data *) 0x60c000007f00)
>       [0x1cdf] ((dwarf2_per_cu_data *) 0)
>       [0x1ce0] ((dwarf2_per_cu_data *) 0x60c000007f00)
>
> The display of address maps above could probably be improved, to show it
> more as ranges, but I think this is a reasonable start.
>
> Note that this patch depends on Pedro Alves' patch "enum_flags
> to_string" [1].  If my patch is to be merged before Pedro's series, I
> will cherry-pick this patch from his series and merge it before mine.
>
> [1] https://inbox.sourceware.org/gdb-patches/20221212203101.1034916-8-pedro@palves.net/

Tested this.  The output looks good to me.

Patch LGTM too.

Thanks,
Andrew

>
> Change-Id: Ida13e479fd4c8d21102ddd732241778bc3b6904a
> ---
>  gdb/dwarf2/cooked-index.c | 16 +++++++++
>  gdb/dwarf2/cooked-index.h |  4 +++
>  gdb/dwarf2/read.c         | 74 ++++++++++++++++++++++++++++++++++++++-
>  3 files changed, 93 insertions(+), 1 deletion(-)
>
> diff --git a/gdb/dwarf2/cooked-index.c b/gdb/dwarf2/cooked-index.c
> index 09b3fd70b262..0dc1c6e2516c 100644
> --- a/gdb/dwarf2/cooked-index.c
> +++ b/gdb/dwarf2/cooked-index.c
> @@ -30,6 +30,22 @@
>  
>  /* See cooked-index.h.  */
>  
> +std::string
> +to_string (cooked_index_flag flags)
> +{
> +  static constexpr cooked_index_flag::string_mapping mapping[] = {
> +    MAP_ENUM_FLAG (IS_MAIN),
> +    MAP_ENUM_FLAG (IS_STATIC),
> +    MAP_ENUM_FLAG (IS_ENUM_CLASS),
> +    MAP_ENUM_FLAG (IS_LINKAGE),
> +    MAP_ENUM_FLAG (IS_TYPE_DECLARATION),
> +  };
> +
> +  return flags.to_string (mapping);
> +}
> +
> +/* See cooked-index.h.  */
> +
>  bool
>  cooked_index_entry::compare (const char *stra, const char *strb,
>  			     bool completing)
> diff --git a/gdb/dwarf2/cooked-index.h b/gdb/dwarf2/cooked-index.h
> index 55eaf9955ab7..7a2e85ecf699 100644
> --- a/gdb/dwarf2/cooked-index.h
> +++ b/gdb/dwarf2/cooked-index.h
> @@ -54,6 +54,10 @@ enum cooked_index_flag_enum : unsigned char
>  };
>  DEF_ENUM_FLAGS_TYPE (enum cooked_index_flag_enum, cooked_index_flag);
>  
> +/* Return a string representation of FLAGS.  */
> +
> +std::string to_string (cooked_index_flag flags);
> +
>  /* A cooked_index_entry represents a single item in the index.  Note
>     that two entries can be created for the same DIE -- one using the
>     name, and another one using the linkage name, if any.
> diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
> index cd937f24ee74..73aafbed80b4 100644
> --- a/gdb/dwarf2/read.c
> +++ b/gdb/dwarf2/read.c
> @@ -93,6 +93,7 @@
>  #include "split-name.h"
>  #include "gdbsupport/parallel-for.h"
>  #include "gdbsupport/thread-pool.h"
> +#include "inferior.h"
>  
>  /* When == 1, print basic high level tracing messages.
>     When > 1, be more verbose.
> @@ -18588,7 +18589,78 @@ struct cooked_index_functions : public dwarf2_base_index_functions
>  
>    void dump (struct objfile *objfile) override
>    {
> -    gdb_printf ("Cooked index in use\n");
> +    gdb_printf ("Cooked index in use:\n");
> +    gdb_printf ("\n");
> +
> +    dwarf2_per_objfile *per_objfile = get_dwarf2_per_objfile (objfile);
> +
> +    cooked_index_vector *table
> +      = (gdb::checked_static_cast<cooked_index_vector *>
> +         (per_objfile->per_bfd->index_table.get ()));
> +
> +    gdb_printf ("  entries:\n");
> +    gdb_printf ("\n");
> +
> +    size_t i = 0;
> +    for (const cooked_index_entry *entry : table->all_entries ())
> +      {
> +	gdb_printf ("    [%zu] ((cooked_index_entry *) %p)\n", i++, entry);
> +	gdb_printf ("    name:       %s\n", entry->name);
> +	gdb_printf ("    canonical:  %s\n", entry->canonical);
> +	gdb_printf ("    DWARF tag:  %s\n", dwarf_tag_name (entry->tag));
> +	gdb_printf ("    flags:      %s\n", to_string (entry->flags).c_str ());
> +	gdb_printf ("    DIE offset: 0x%lx\n",
> +		    to_underlying (entry->die_offset));
> +
> +	if (entry->parent_entry != nullptr)
> +	  gdb_printf ("    parent:     ((cooked_index_entry *) %p) [%s]\n",
> +		      entry->parent_entry, entry->parent_entry->name);
> +	else
> +	  gdb_printf ("    parent:     ((cooked_index_entry *) 0)\n");
> +
> +	gdb_printf ("\n");
> +      }
> +
> +    const cooked_index_entry *main_entry = table->get_main ();
> +    if (main_entry != nullptr)
> +      gdb_printf ("  main: ((cooked_index_entry *) %p) [%s]\n", main_entry,
> +		  main_entry->name);
> +    else
> +      gdb_printf ("  main: ((cooked_index_entry *) 0)\n");
> +
> +    gdb_printf ("\n");
> +    gdb_printf ("  address maps:\n");
> +    gdb_printf ("\n");
> +
> +    std::vector<addrmap *> addrmaps = table->get_addrmaps ();
> +    for (i = 0; i < addrmaps.size (); ++i)
> +      {
> +	addrmap &addrmap = *addrmaps[i];
> +
> +	gdb_printf ("    [%zu] ((addrmap *) %p)\n", i, &addrmap);
> +	gdb_printf ("\n");
> +
> +	addrmap.foreach ([] (CORE_ADDR start_addr, void *obj)
> +	  {
> +	    const char *start_addr_str
> +	      = paddress (current_inferior ()->gdbarch, start_addr);
> +
> +	    if (obj != nullptr)
> +	      {
> +		const dwarf2_per_cu_data *per_cu
> +		  = (const dwarf2_per_cu_data *) obj;
> +		gdb_printf ("      [%s] ((dwarf2_per_cu_data *) %p)\n",
> +			    start_addr_str, per_cu);
> +	      }
> +	    else
> +	      gdb_printf ("      [%s] ((dwarf2_per_cu_data *) 0)\n",
> +			  start_addr_str);
> +
> +	    return 0;
> +	  });
> +
> +	gdb_printf ("\n");
> +      }
>    }
>  
>    void expand_matching_symbols
>
> base-commit: 48afe8b710712bf131fadbfa3278e512a7034483
> -- 
> 2.39.0
  

>>>>> "Simon" == Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:

Simon> The cooked_index_functions::dump function is called as part of the
Simon> "maintenance print objfiles" command.  I tried to make the output
Simon> well structured and indented to help readability, as this prints a lot
Simon> of text.

Thanks for doing this.

Simon> diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
Simon> index cd937f24ee74..73aafbed80b4 100644
Simon> --- a/gdb/dwarf2/read.c
Simon> +++ b/gdb/dwarf2/read.c
Simon> @@ -93,6 +93,7 @@
Simon>  #include "split-name.h"
Simon>  #include "gdbsupport/parallel-for.h"
Simon>  #include "gdbsupport/thread-pool.h"
Simon> +#include "inferior.h"
 
Simon>  /* When == 1, print basic high level tracing messages.
Simon>     When > 1, be more verbose.
Simon> @@ -18588,7 +18589,78 @@ struct cooked_index_functions : public dwarf2_base_index_functions
 
Simon>    void dump (struct objfile *objfile) override
Simon>    {
Simon> -    gdb_printf ("Cooked index in use\n");
Simon> +    gdb_printf ("Cooked index in use:\n");
Simon> +    gdb_printf ("\n");

I think I'd rather have the bulk of the dumping in the cooked-index code
instead of here.

Simon> +
Simon> +    dwarf2_per_objfile *per_objfile = get_dwarf2_per_objfile (objfile);
Simon> +
Simon> +    cooked_index_vector *table
Simon> +      = (gdb::checked_static_cast<cooked_index_vector *>
Simon> +         (per_objfile->per_bfd->index_table.get ()));

Like right here could be a method call.

The cooked index dumper should probably start with a call to 'wait' to
ensure that no background work is being done.

Simon> +	    const char *start_addr_str
Simon> +	      = paddress (current_inferior ()->gdbarch, start_addr);

I was curious why the inferior.h include was needed.
I suspect the objfile's arch is preferred here.

Tom
  

> Simon> +
> Simon> +    dwarf2_per_objfile *per_objfile = get_dwarf2_per_objfile (objfile);
> Simon> +
> Simon> +    cooked_index_vector *table
> Simon> +      = (gdb::checked_static_cast<cooked_index_vector *>
> Simon> +         (per_objfile->per_bfd->index_table.get ()));
> 
> Like right here could be a method call.
> 
> The cooked index dumper should probably start with a call to 'wait' to
> ensure that no background work is being done.
Ah, that makes sense.

> Simon> +	    const char *start_addr_str
> Simon> +	      = paddress (current_inferior ()->gdbarch, start_addr);
> 
> I was curious why the inferior.h include was needed.
> I suspect the objfile's arch is preferred here.

Ah, I forgot that objfiles had arches.  Makes sense.

I'll send a v2 with those fixed.

Simon