[PATCH v2] gdb/dwarf: dump cooked index contents in cooked_index_functions::dump

Simon Marchi via Gdb-patches
2023-01-30T16:04:06Z

From: Simon Marchi <simon.marchi@polymtl.ca>

New in v2:

- move the implementation to the cooked_index_vector class
- use the gdbarch from the objfile
- add some QUIT macro calls
- add call to wait, to ensure the index is finished

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 | 93 +++++++++++++++++++++++++++++++++++++++
gdb/dwarf2/cooked-index.h | 7 +++
gdb/dwarf2/read.c | 10 ++++-
3 files changed, 109 insertions(+), 1 deletion(-)

diff --git a/gdb/dwarf2/cooked-index.c b/gdb/dwarf2/cooked-index.c
index 646bc76575cd..0ee7afb7b978 100644
--- a/gdb/dwarf2/cooked-index.c
+++ b/gdb/dwarf2/cooked-index.c
@@ -20,6 +20,7 @@
#include "defs.h"
#include "dwarf2/cooked-index.h"
#include "dwarf2/read.h"
+#include "dwarf2/stringify.h"
#include "cp-support.h"
#include "c-lang.h"
#include "ada-lang.h"
@@ -30,6 +31,22 @@

/* 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)
@@ -442,6 +459,82 @@ cooked_index_vector::get_main () const
return result;
}

+/* See cooked-index.h. */
+
+void
+cooked_index_vector::dump (gdbarch *arch) const
+{
+ /* Ensure the index is done building. */
+ this->wait ();
+
+ gdb_printf (" entries:\n");
+ gdb_printf ("\n");
+
+ size_t i = 0;
+ for (const cooked_index_entry *entry : this->all_entries ())
+ {
+ QUIT;
+
+ 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 = this->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<const addrmap *> addrmaps = this->get_addrmaps ();
+ for (i = 0; i < addrmaps.size (); ++i)
+ {
+ const addrmap &addrmap = *addrmaps[i];
+
+ gdb_printf (" [%zu] ((addrmap *) %p)\n", i, &addrmap);
+ gdb_printf ("\n");
+
+ addrmap.foreach ([arch] (CORE_ADDR start_addr, const void *obj)
+ {
+ QUIT;
+
+ const char *start_addr_str = paddress (arch, start_addr);
+
+ if (obj != nullptr)
+ {
+ const dwarf2_per_cu_data *per_cu
+ = static_cast<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 _initialize_cooked_index ();
void
_initialize_cooked_index ()
diff --git a/gdb/dwarf2/cooked-index.h b/gdb/dwarf2/cooked-index.h
index 7299a4f77b44..9d9be517c3a9 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.
@@ -373,6 +377,9 @@ class cooked_index_vector : public dwarf_scanner_base

quick_symbol_functions_up make_quick_functions () const override;

+ /* Dump a human-readable form of the contents of the index. */
+ void dump (gdbarch *arch) const;
+
private:

/* The vector of cooked_index objects. This is stored because the
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 9d8952a4eb8d..16559133a3d0 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -18589,7 +18589,15 @@ 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 *index
+ = (gdb::checked_static_cast<cooked_index_vector *>
+ (per_objfile->per_bfd->index_table.get ()));
+
+ index->dump (objfile->arch ());
}

void expand_matching_symbols
--
2.39.1