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

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

@@ -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.  */
+
 int
 cooked_index_entry::compare (const char *stra, const char *strb,
 			     comparison_mode mode)
@@ -451,6 +468,82 @@ 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 ()

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.
@@ -411,6 +415,9 @@ public:
 
   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

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