gdb/symtab.c

/* Symbol table lookup for the GNU debugger, GDB.

   Copyright (C) 1986-2024 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "dwarf2/call-site.h"
#include "symtab.h"
#include "event-top.h"
#include "gdbtypes.h"
#include "gdbcore.h"
#include "frame.h"
#include "target.h"
#include "value.h"
#include "symfile.h"
#include "objfiles.h"
#include "gdbsupport/gdb_regex.h"
#include "expression.h"
#include "language.h"
#include "demangle.h"
#include "inferior.h"
#include "source.h"
#include "filenames.h"
#include "objc-lang.h"
#include "d-lang.h"
#include "ada-lang.h"
#include "go-lang.h"
#include "p-lang.h"
#include "addrmap.h"
#include "cli/cli-utils.h"
#include "cli/cli-style.h"
#include "cli/cli-cmds.h"
#include "fnmatch.h"
#include "hashtab.h"
#include "typeprint.h"

#include "gdbsupport/gdb_obstack.h"
#include "block.h"
#include "dictionary.h"

#include <sys/types.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <ctype.h>
#include "cp-abi.h"
#include "cp-support.h"
#include "observable.h"
#include "solist.h"
#include "macrotab.h"
#include "macroscope.h"

#include "parser-defs.h"
#include "completer.h"
#include "progspace-and-thread.h"
#include <optional>
#include "filename-seen-cache.h"
#include "arch-utils.h"
#include <algorithm>
#include <string_view>
#include "gdbsupport/pathstuff.h"
#include "gdbsupport/common-utils.h"
#include <optional>

/* Forward declarations for local functions.  */

static void rbreak_command (const char *, int);

static int find_line_common (const linetable *, int, int *, int);

static struct block_symbol
  lookup_symbol_aux (const char *name,
		     symbol_name_match_type match_type,
		     const struct block *block,
		     const domain_search_flags domain,
		     enum language language,
		     struct field_of_this_result *);

static
struct block_symbol lookup_local_symbol (const char *name,
					 symbol_name_match_type match_type,
					 const struct block *block,
					 const domain_search_flags domain,
					 const struct language_defn *langdef);

static struct block_symbol
  lookup_symbol_in_objfile (struct objfile *objfile,
			    enum block_enum block_index,
			    const char *name,
			    const domain_search_flags domain);

static void set_main_name (program_space *pspace, const char *name,
			   language lang);

/* Type of the data stored on the program space.  */

struct main_info
{
  /* Name of "main".  */

  std::string name_of_main;

  /* Language of "main".  */

  enum language language_of_main = language_unknown;
};

/* Program space key for finding name and language of "main".  */

static const registry<program_space>::key<main_info> main_progspace_key;

/* The default symbol cache size.
   There is no extra cpu cost for large N (except when flushing the cache,
   which is rare).  The value here is just a first attempt.  A better default
   value may be higher or lower.  A prime number can make up for a bad hash
   computation, so that's why the number is what it is.  */
#define DEFAULT_SYMBOL_CACHE_SIZE 1021

/* The maximum symbol cache size.
   There's no method to the decision of what value to use here, other than
   there's no point in allowing a user typo to make gdb consume all memory.  */
#define MAX_SYMBOL_CACHE_SIZE (1024*1024)

/* symbol_cache_lookup returns this if a previous lookup failed to find the
   symbol in any objfile.  */
#define SYMBOL_LOOKUP_FAILED \
 ((struct block_symbol) {(struct symbol *) 1, NULL})
#define SYMBOL_LOOKUP_FAILED_P(SIB) (SIB.symbol == (struct symbol *) 1)

/* Recording lookups that don't find the symbol is just as important, if not
   more so, than recording found symbols.  */

enum symbol_cache_slot_state
{
  SYMBOL_SLOT_UNUSED,
  SYMBOL_SLOT_NOT_FOUND,
  SYMBOL_SLOT_FOUND
};

struct symbol_cache_slot
{
  enum symbol_cache_slot_state state;

  /* The objfile that was current when the symbol was looked up.
     This is only needed for global blocks, but for simplicity's sake
     we allocate the space for both.  If data shows the extra space used
     for static blocks is a problem, we can split things up then.

     Global blocks need cache lookup to include the objfile context because
     we need to account for gdbarch_iterate_over_objfiles_in_search_order
     which can traverse objfiles in, effectively, any order, depending on
     the current objfile, thus affecting which symbol is found.  Normally,
     only the current objfile is searched first, and then the rest are
     searched in recorded order; but putting cache lookup inside
     gdbarch_iterate_over_objfiles_in_search_order would be awkward.
     Instead we just make the current objfile part of the context of
     cache lookup.  This means we can record the same symbol multiple times,
     each with a different "current objfile" that was in effect when the
     lookup was saved in the cache, but cache space is pretty cheap.  */
  const struct objfile *objfile_context;

  /* The domain that was searched for initially.  This must exactly
     match.  */
  domain_search_flags domain;

  union
  {
    struct block_symbol found;
    char *name;
  } value;
};

/* Clear out SLOT.  */

static void
symbol_cache_clear_slot (struct symbol_cache_slot *slot)
{
  if (slot->state == SYMBOL_SLOT_NOT_FOUND)
    xfree (slot->value.name);
  slot->state = SYMBOL_SLOT_UNUSED;
}

/* Symbols don't specify global vs static block.
   So keep them in separate caches.  */

struct block_symbol_cache
{
  unsigned int hits;
  unsigned int misses;
  unsigned int collisions;

  /* SYMBOLS is a variable length array of this size.
     One can imagine that in general one cache (global/static) should be a
     fraction of the size of the other, but there's no data at the moment
     on which to decide.  */
  unsigned int size;

  struct symbol_cache_slot symbols[1];
};

/* Clear all slots of BSC and free BSC.  */

static void
destroy_block_symbol_cache (struct block_symbol_cache *bsc)
{
  if (bsc != nullptr)
    {
      for (unsigned int i = 0; i < bsc->size; i++)
	symbol_cache_clear_slot (&bsc->symbols[i]);
      xfree (bsc);
    }
}

/* The symbol cache.

   Searching for symbols in the static and global blocks over multiple objfiles
   again and again can be slow, as can searching very big objfiles.  This is a
   simple cache to improve symbol lookup performance, which is critical to
   overall gdb performance.

   Symbols are hashed on the name, its domain, and block.
   They are also hashed on their objfile for objfile-specific lookups.  */

struct symbol_cache
{
  symbol_cache () = default;

  ~symbol_cache ()
  {
    destroy_block_symbol_cache (global_symbols);
    destroy_block_symbol_cache (static_symbols);
  }

  struct block_symbol_cache *global_symbols = nullptr;
  struct block_symbol_cache *static_symbols = nullptr;
};

/* Program space key for finding its symbol cache.  */

static const registry<program_space>::key<symbol_cache> symbol_cache_key;

/* When non-zero, print debugging messages related to symtab creation.  */
unsigned int symtab_create_debug = 0;

/* When non-zero, print debugging messages related to symbol lookup.  */
unsigned int symbol_lookup_debug = 0;

/* The size of the cache is staged here.  */
static unsigned int new_symbol_cache_size = DEFAULT_SYMBOL_CACHE_SIZE;

/* The current value of the symbol cache size.
   This is saved so that if the user enters a value too big we can restore
   the original value from here.  */
static unsigned int symbol_cache_size = DEFAULT_SYMBOL_CACHE_SIZE;

/* True 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.  */
bool basenames_may_differ = false;

/* Allow the user to configure the debugger behavior with respect
   to multiple-choice menus when more than one symbol matches during
   a symbol lookup.  */

const char multiple_symbols_ask[] = "ask";
const char multiple_symbols_all[] = "all";
const char multiple_symbols_cancel[] = "cancel";
static const char *const multiple_symbols_modes[] =
{
  multiple_symbols_ask,
  multiple_symbols_all,
  multiple_symbols_cancel,
  NULL
};
static const char *multiple_symbols_mode = multiple_symbols_all;

/* When TRUE, ignore the prologue-end flag in linetable_entry when searching
   for the SAL past a function prologue.  */
static bool ignore_prologue_end_flag = false;

/* Read-only accessor to AUTO_SELECT_MODE.  */

const char *
multiple_symbols_select_mode (void)
{
  return multiple_symbols_mode;
}

/* Return the name of a domain_enum.  */

const char *
domain_name (domain_enum e)
{
  switch (e)
    {
#define SYM_DOMAIN(X)				\
      case X ## _DOMAIN: return #X "_DOMAIN";
#include "sym-domains.def"
#undef SYM_DOMAIN
    default: gdb_assert_not_reached ("bad domain_enum");
    }
}

/* See symtab.h.  */

std::string
domain_name (domain_search_flags flags)
{
  static constexpr domain_search_flags::string_mapping mapping[] = {
#define SYM_DOMAIN(X) \
    MAP_ENUM_FLAG (SEARCH_ ## X ## _DOMAIN),
#include "sym-domains.def"
#undef SYM_DOMAIN
  };

  return flags.to_string (mapping);
}

/* See symtab.h.  */

domain_search_flags
from_scripting_domain (int val)
{
  if ((val & SCRIPTING_SEARCH_FLAG) == 0)
    {
      /* VAL should be one of the domain constants.  Verify this and
	 convert it to a search constant.  */
      switch (val)
	{
#define SYM_DOMAIN(X)					\
	  case X ## _DOMAIN: break;
#include "sym-domains.def"
#undef SYM_DOMAIN
	default:
	  error (_("unrecognized domain constant"));
	}
      domain_search_flags result = to_search_flags ((domain_enum) val);
      if (val == VAR_DOMAIN)
	{
	  /* This matches the historical practice.  */
	  result |= SEARCH_TYPE_DOMAIN | SEARCH_FUNCTION_DOMAIN;
	}
      return result;
    }
  else
    {
      /* VAL is several search constants or'd together.  Verify
	 this.  */
      val &= ~SCRIPTING_SEARCH_FLAG;
      int check = val;
#define SYM_DOMAIN(X)				\
      check &= ~ (int) SEARCH_ ## X ## _DOMAIN;
#include "sym-domains.def"
#undef SYM_DOMAIN
      if (check != 0)
	error (_("unrecognized domain constant"));
      return (domain_search_flag) val;
    }
}

/* See symtab.h.  */

struct symbol *
search_symbol_list (const char *name, int num, struct symbol **syms)
{
  for (int i = 0; i < num; ++i)
    {
      if (strcmp (name, syms[i]->natural_name ()) == 0)
	return syms[i];
    }
  return nullptr;
}

/* See symtab.h.  */

CORE_ADDR
linetable_entry::pc (const struct objfile *objfile) const
{
  return CORE_ADDR (m_pc) + objfile->text_section_offset ();
}

/* See symtab.h.  */

call_site *
compunit_symtab::find_call_site (CORE_ADDR pc) const
{
  if (m_call_site_htab == nullptr)
    return nullptr;

  CORE_ADDR delta = this->objfile ()->text_section_offset ();
  unrelocated_addr unrelocated_pc = (unrelocated_addr) (pc - delta);

  struct call_site call_site_local (unrelocated_pc, nullptr, nullptr);
  void **slot
    = htab_find_slot (m_call_site_htab, &call_site_local, NO_INSERT);
  if (slot != nullptr)
    return (call_site *) *slot;

  /* See if the arch knows another PC we should try.  On some
     platforms, GCC emits a DWARF call site that is offset from the
     actual return location.  */
  struct gdbarch *arch = objfile ()->arch ();
  CORE_ADDR new_pc = gdbarch_update_call_site_pc (arch, pc);
  if (pc == new_pc)
    return nullptr;

  unrelocated_pc = (unrelocated_addr) (new_pc - delta);
  call_site new_call_site_local (unrelocated_pc, nullptr, nullptr);
  slot = htab_find_slot (m_call_site_htab, &new_call_site_local, NO_INSERT);
  if (slot == nullptr)
    return nullptr;

  return (call_site *) *slot;
}

/* See symtab.h.  */

void
compunit_symtab::set_call_site_htab (htab_up call_site_htab)
{
  gdb_assert (m_call_site_htab == nullptr);
  m_call_site_htab = call_site_htab.release ();
}

/* See symtab.h.  */

void
compunit_symtab::set_primary_filetab (symtab *primary_filetab)
{
  symtab *prev_filetab = nullptr;

  /* Move PRIMARY_FILETAB to the head of the filetab list.  */
  for (symtab *filetab : this->filetabs ())
    {
      if (filetab == primary_filetab)
	{
	  if (prev_filetab != nullptr)
	    {
	      prev_filetab->next = primary_filetab->next;
	      primary_filetab->next = m_filetabs;
	      m_filetabs = primary_filetab;
	    }

	  break;
	}

      prev_filetab = filetab;
    }

  gdb_assert (primary_filetab == m_filetabs);
}

/* See symtab.h.  */

struct symtab *
compunit_symtab::primary_filetab () const
{
  gdb_assert (m_filetabs != nullptr);

  /* The primary file symtab is the first one in the list.  */
  return m_filetabs;
}

/* See symtab.h.  */

enum language
compunit_symtab::language () const
{
  struct symtab *symtab = primary_filetab ();

  /* The language of the compunit symtab is the language of its
     primary source file.  */
  return symtab->language ();
}

/* See symtab.h.  */

void
compunit_symtab::forget_cached_source_info ()
{
  for (symtab *s : filetabs ())
    s->release_fullname ();
}

/* See symtab.h.  */

void
compunit_symtab::finalize ()
{
  this->forget_cached_source_info ();
  if (m_call_site_htab != nullptr)
    htab_delete (m_call_site_htab);
}

/* The relocated address of the minimal symbol, using the section
   offsets from OBJFILE.  */

CORE_ADDR
minimal_symbol::value_address (objfile *objfile) const
{
  if (this->maybe_copied (objfile))
    return this->get_maybe_copied_address (objfile);
  else
    return (CORE_ADDR (this->unrelocated_address ())
	    + objfile->section_offsets[this->section_index ()]);
}

/* See symtab.h.  */

bool
minimal_symbol::data_p () const
{
  return m_type == mst_data
    || m_type == mst_bss
    || m_type == mst_abs
    || m_type == mst_file_data
    || m_type == mst_file_bss;
}

/* See symtab.h.  */

bool
minimal_symbol::text_p () const
{
  return m_type == mst_text
    || m_type == mst_text_gnu_ifunc
    || m_type == mst_data_gnu_ifunc
    || m_type == mst_slot_got_plt
    || m_type == mst_solib_trampoline
    || m_type == mst_file_text;
}

/* See symtab.h.  */

bool
minimal_symbol::maybe_copied (objfile *objfile) const
{
  return (objfile->object_format_has_copy_relocs
	  && (objfile->flags & OBJF_MAINLINE) == 0
	  && (m_type == mst_data || m_type == mst_bss));
}

/* See whether FILENAME matches SEARCH_NAME using the rule that we
   advertise to the user.  (The manual's description of linespecs
   describes what we advertise).  Returns true if they match, false
   otherwise.  */

bool
compare_filenames_for_search (const char *filename, const char *search_name)
{
  int len = strlen (filename);
  size_t search_len = strlen (search_name);

  if (len < search_len)
    return false;

  /* The tail of FILENAME must match.  */
  if (FILENAME_CMP (filename + len - search_len, search_name) != 0)
    return false;

  /* Either the names must completely match, or the character
     preceding the trailing SEARCH_NAME segment of FILENAME must be a
     directory separator.

     The check !IS_ABSOLUTE_PATH ensures SEARCH_NAME "/dir/file.c"
     cannot match FILENAME "/path//dir/file.c" - as user has requested
     absolute path.  The sama applies for "c:\file.c" possibly
     incorrectly hypothetically matching "d:\dir\c:\file.c".

     The HAS_DRIVE_SPEC purpose is to make FILENAME "c:file.c"
     compatible with SEARCH_NAME "file.c".  In such case a compiler had
     to put the "c:file.c" name into debug info.  Such compatibility
     works only on GDB built for DOS host.  */
  return (len == search_len
	  || (!IS_ABSOLUTE_PATH (search_name)
	      && IS_DIR_SEPARATOR (filename[len - search_len - 1]))
	  || (HAS_DRIVE_SPEC (filename)
	      && STRIP_DRIVE_SPEC (filename) == &filename[len - search_len]));
}

/* Same as compare_filenames_for_search, but for glob-style patterns.
   Heads up on the order of the arguments.  They match the order of
   compare_filenames_for_search, but it's the opposite of the order of
   arguments to gdb_filename_fnmatch.  */

bool
compare_glob_filenames_for_search (const char *filename,
				   const char *search_name)
{
  /* We rely on the property of glob-style patterns with FNM_FILE_NAME that
     all /s have to be explicitly specified.  */
  int file_path_elements = count_path_elements (filename);
  int search_path_elements = count_path_elements (search_name);

  if (search_path_elements > file_path_elements)
    return false;

  if (IS_ABSOLUTE_PATH (search_name))
    {
      return (search_path_elements == file_path_elements
	      && gdb_filename_fnmatch (search_name, filename,
				       FNM_FILE_NAME | FNM_NOESCAPE) == 0);
    }

  {
    const char *file_to_compare
      = strip_leading_path_elements (filename,
				     file_path_elements - search_path_elements);

    return gdb_filename_fnmatch (search_name, file_to_compare,
				 FNM_FILE_NAME | FNM_NOESCAPE) == 0;
  }
}

/* Check for a symtab of a specific name by searching some symtabs.
   This is a helper function for callbacks of iterate_over_symtabs.

   If NAME is not absolute, then REAL_PATH is NULL
   If NAME is absolute, then REAL_PATH is the gdb_realpath form of NAME.

   The return value, NAME, REAL_PATH and CALLBACK are identical to the
   `map_symtabs_matching_filename' method of quick_symbol_functions.

   FIRST and AFTER_LAST indicate the range of compunit symtabs to search.
   Each symtab within the specified compunit symtab is also searched.
   AFTER_LAST is one past the last compunit symtab to search; NULL means to
   search until the end of the list.  */

bool
iterate_over_some_symtabs (const char *name,
			   const char *real_path,
			   struct compunit_symtab *first,
			   struct compunit_symtab *after_last,
			   gdb::function_view<bool (symtab *)> callback)
{
  struct compunit_symtab *cust;
  const char* base_name = lbasename (name);

  for (cust = first; cust != NULL && cust != after_last; cust = cust->next)
    {
      /* Skip included compunits.  */
      if (cust->user != nullptr)
	continue;

      for (symtab *s : cust->filetabs ())
	{
	  if (compare_filenames_for_search (s->filename, name))
	    {
	      if (callback (s))
		return true;
	      continue;
	    }

	  /* Before we invoke realpath, which can get expensive when many
	     files are involved, do a quick comparison of the basenames.  */
	  if (! basenames_may_differ
	      && FILENAME_CMP (base_name, lbasename (s->filename)) != 0)
	    continue;

	  if (compare_filenames_for_search (symtab_to_fullname (s), name))
	    {
	      if (callback (s))
		return true;
	      continue;
	    }

	  /* If the user gave us an absolute path, try to find the file in
	     this symtab and use its absolute path.  */
	  if (real_path != NULL)
	    {
	      const char *fullname = symtab_to_fullname (s);

	      gdb_assert (IS_ABSOLUTE_PATH (real_path));
	      gdb_assert (IS_ABSOLUTE_PATH (name));
	      gdb::unique_xmalloc_ptr<char> fullname_real_path
		= gdb_realpath (fullname);
	      fullname = fullname_real_path.get ();
	      if (FILENAME_CMP (real_path, fullname) == 0)
		{
		  if (callback (s))
		    return true;
		  continue;
		}
	    }
	}
    }

  return false;
}

/* Check for a symtab of a specific name; first in symtabs, then in
   psymtabs.  *If* there is no '/' in the name, a match after a '/'
   in the symtab filename will also work.

   Calls CALLBACK with each symtab that is found.  If CALLBACK returns
   true, the search stops.  */

void
iterate_over_symtabs (const char *name,
		      gdb::function_view<bool (symtab *)> callback)
{
  gdb::unique_xmalloc_ptr<char> real_path;

  /* Here we are interested in canonicalizing an absolute path, not
     absolutizing a relative path.  */
  if (IS_ABSOLUTE_PATH (name))
    {
      real_path = gdb_realpath (name);
      gdb_assert (IS_ABSOLUTE_PATH (real_path.get ()));
    }

  for (objfile *objfile : current_program_space->objfiles ())
    {
      if (iterate_over_some_symtabs (name, real_path.get (),
				     objfile->compunit_symtabs, NULL,
				     callback))
	return;
    }

  /* Same search rules as above apply here, but now we look thru the
     psymtabs.  */

  for (objfile *objfile : current_program_space->objfiles ())
    {
      if (objfile->map_symtabs_matching_filename (name, real_path.get (),
						  callback))
	return;
    }
}

/* A wrapper for iterate_over_symtabs that returns the first matching
   symtab, or NULL.  */

struct symtab *
lookup_symtab (const char *name)
{
  struct symtab *result = NULL;

  iterate_over_symtabs (name, [&] (symtab *symtab)
    {
      result = symtab;
      return true;
    });

  return result;
}


/* Mangle a GDB method stub type.  This actually reassembles the pieces of the
   full method name, which consist of the class name (from T), the unadorned
   method name from METHOD_ID, and the signature for the specific overload,
   specified by SIGNATURE_ID.  Note that this function is g++ specific.  */

char *
gdb_mangle_name (struct type *type, int method_id, int signature_id)
{
  int mangled_name_len;
  char *mangled_name;
  struct fn_field *f = TYPE_FN_FIELDLIST1 (type, method_id);
  struct fn_field *method = &f[signature_id];
  const char *field_name = TYPE_FN_FIELDLIST_NAME (type, method_id);
  const char *physname = TYPE_FN_FIELD_PHYSNAME (f, signature_id);
  const char *newname = type->name ();

  /* Does the form of physname indicate that it is the full mangled name
     of a constructor (not just the args)?  */
  int is_full_physname_constructor;

  int is_constructor;
  int is_destructor = is_destructor_name (physname);
  /* Need a new type prefix.  */
  const char *const_prefix = method->is_const ? "C" : "";
  const char *volatile_prefix = method->is_volatile ? "V" : "";
  char buf[20];
  int len = (newname == NULL ? 0 : strlen (newname));

  /* Nothing to do if physname already contains a fully mangled v3 abi name
     or an operator name.  */
  if ((physname[0] == '_' && physname[1] == 'Z')
      || is_operator_name (field_name))
    return xstrdup (physname);

  is_full_physname_constructor = is_constructor_name (physname);

  is_constructor = is_full_physname_constructor 
    || (newname && strcmp (field_name, newname) == 0);

  if (!is_destructor)
    is_destructor = (startswith (physname, "__dt"));

  if (is_destructor || is_full_physname_constructor)
    {
      mangled_name = (char *) xmalloc (strlen (physname) + 1);
      strcpy (mangled_name, physname);
      return mangled_name;
    }

  if (len == 0)
    {
      xsnprintf (buf, sizeof (buf), "__%s%s", const_prefix, volatile_prefix);
    }
  else if (physname[0] == 't' || physname[0] == 'Q')
    {
      /* The physname for template and qualified methods already includes
	 the class name.  */
      xsnprintf (buf, sizeof (buf), "__%s%s", const_prefix, volatile_prefix);
      newname = NULL;
      len = 0;
    }
  else
    {
      xsnprintf (buf, sizeof (buf), "__%s%s%d", const_prefix,
		 volatile_prefix, len);
    }
  mangled_name_len = ((is_constructor ? 0 : strlen (field_name))
		      + strlen (buf) + len + strlen (physname) + 1);

  mangled_name = (char *) xmalloc (mangled_name_len);
  if (is_constructor)
    mangled_name[0] = '\0';
  else
    strcpy (mangled_name, field_name);

  strcat (mangled_name, buf);
  /* If the class doesn't have a name, i.e. newname NULL, then we just
     mangle it using 0 for the length of the class.  Thus it gets mangled
     as something starting with `::' rather than `classname::'.  */
  if (newname != NULL)
    strcat (mangled_name, newname);

  strcat (mangled_name, physname);
  return (mangled_name);
}

/* See symtab.h.  */

void
general_symbol_info::set_demangled_name (const char *name,
					 struct obstack *obstack)
{
  if (language () == language_ada)
    {
      if (name == NULL)
	{
	  ada_mangled = 0;
	  language_specific.obstack = obstack;
	}
      else
	{
	  ada_mangled = 1;
	  language_specific.demangled_name = name;
	}
    }
  else
    language_specific.demangled_name = name;
}


/* Initialize the language dependent portion of a symbol
   depending upon the language for the symbol.  */

void
general_symbol_info::set_language (enum language language,
				   struct obstack *obstack)
{
  m_language = language;
  if (language == language_cplus
      || language == language_d
      || language == language_go
      || language == language_objc
      || language == language_fortran)
    {
      set_demangled_name (NULL, obstack);
    }
  else if (language == language_ada)
    {
      gdb_assert (ada_mangled == 0);
      language_specific.obstack = obstack;
    }
  else
    {
      memset (&language_specific, 0, sizeof (language_specific));
    }
}

/* Functions to initialize a symbol's mangled name.  */

/* Objects of this type are stored in the demangled name hash table.  */
struct demangled_name_entry
{
  demangled_name_entry (std::string_view mangled_name)
    : mangled (mangled_name) {}

  std::string_view mangled;
  enum language language;
  gdb::unique_xmalloc_ptr<char> demangled;
};

/* Hash function for the demangled name hash.  */

static hashval_t
hash_demangled_name_entry (const void *data)
{
  const struct demangled_name_entry *e
    = (const struct demangled_name_entry *) data;

  return gdb::string_view_hash () (e->mangled);
}

/* Equality function for the demangled name hash.  */

static int
eq_demangled_name_entry (const void *a, const void *b)
{
  const struct demangled_name_entry *da
    = (const struct demangled_name_entry *) a;
  const struct demangled_name_entry *db
    = (const struct demangled_name_entry *) b;

  return da->mangled == db->mangled;
}

static void
free_demangled_name_entry (void *data)
{
  struct demangled_name_entry *e
    = (struct demangled_name_entry *) data;

  e->~demangled_name_entry();
}

/* Create the hash table used for demangled names.  Each hash entry is
   a pair of strings; one for the mangled name and one for the demangled
   name.  The entry is hashed via just the mangled name.  */

static void
create_demangled_names_hash (struct objfile_per_bfd_storage *per_bfd)
{
  /* Choose 256 as the starting size of the hash table, somewhat arbitrarily.
     The hash table code will round this up to the next prime number.
     Choosing a much larger table size wastes memory, and saves only about
     1% in symbol reading.  However, if the minsym count is already
     initialized (e.g. because symbol name setting was deferred to
     a background thread) we can initialize the hashtable with a count
     based on that, because we will almost certainly have at least that
     many entries.  If we have a nonzero number but less than 256,
     we still stay with 256 to have some space for psymbols, etc.  */

  /* htab will expand the table when it is 3/4th full, so we account for that
     here.  +2 to round up.  */
  int minsym_based_count = (per_bfd->minimal_symbol_count + 2) / 3 * 4;
  int count = std::max (per_bfd->minimal_symbol_count, minsym_based_count);

  per_bfd->demangled_names_hash.reset (htab_create_alloc
    (count, hash_demangled_name_entry, eq_demangled_name_entry,
     free_demangled_name_entry, xcalloc, xfree));
}

/* See symtab.h  */

gdb::unique_xmalloc_ptr<char>
symbol_find_demangled_name (struct general_symbol_info *gsymbol,
			    const char *mangled)
{
  gdb::unique_xmalloc_ptr<char> demangled;
  int i;

  if (gsymbol->language () != language_unknown)
    {
      const struct language_defn *lang = language_def (gsymbol->language ());

      lang->sniff_from_mangled_name (mangled, &demangled);
      return demangled;
    }

  for (i = language_unknown; i < nr_languages; ++i)
    {
      enum language l = (enum language) i;
      const struct language_defn *lang = language_def (l);

      if (lang->sniff_from_mangled_name (mangled, &demangled))
	{
	  gsymbol->m_language = l;
	  return demangled;
	}
    }

  return NULL;
}

/* Set both the mangled and demangled (if any) names for GSYMBOL based
   on LINKAGE_NAME and LEN.  Ordinarily, NAME is copied onto the
   objfile's obstack; but if COPY_NAME is 0 and if NAME is
   NUL-terminated, then this function assumes that NAME is already
   correctly saved (either permanently or with a lifetime tied to the
   objfile), and it will not be copied.

   The hash table corresponding to OBJFILE is used, and the memory
   comes from the per-BFD storage_obstack.  LINKAGE_NAME is copied,
   so the pointer can be discarded after calling this function.  */

void
general_symbol_info::compute_and_set_names (std::string_view linkage_name,
					    bool copy_name,
					    objfile_per_bfd_storage *per_bfd,
					    std::optional<hashval_t> hash)
{
  struct demangled_name_entry **slot;

  if (language () == language_ada)
    {
      /* In Ada, we do the symbol lookups using the mangled name, so
	 we can save some space by not storing the demangled name.  */
      if (!copy_name)
	m_name = linkage_name.data ();
      else
	m_name = obstack_strndup (&per_bfd->storage_obstack,
				  linkage_name.data (),
				  linkage_name.length ());
      set_demangled_name (NULL, &per_bfd->storage_obstack);

      return;
    }

  if (per_bfd->demangled_names_hash == NULL)
    create_demangled_names_hash (per_bfd);

  struct demangled_name_entry entry (linkage_name);
  if (!hash.has_value ())
    hash = hash_demangled_name_entry (&entry);
  slot = ((struct demangled_name_entry **)
	  htab_find_slot_with_hash (per_bfd->demangled_names_hash.get (),
				    &entry, *hash, INSERT));

  /* The const_cast is safe because the only reason it is already
     initialized is if we purposefully set it from a background
     thread to avoid doing the work here.  However, it is still
     allocated from the heap and needs to be freed by us, just
     like if we called symbol_find_demangled_name here.  If this is
     nullptr, we call symbol_find_demangled_name below, but we put
     this smart pointer here to be sure that we don't leak this name.  */
  gdb::unique_xmalloc_ptr<char> demangled_name
    (const_cast<char *> (language_specific.demangled_name));

  /* If this name is not in the hash table, add it.  */
  if (*slot == NULL
      /* A C version of the symbol may have already snuck into the table.
	 This happens to, e.g., main.init (__go_init_main).  Cope.  */
      || (language () == language_go && (*slot)->demangled == nullptr))
    {
      /* A 0-terminated copy of the linkage name.  Callers must set COPY_NAME
	 to true if the string might not be nullterminated.  We have to make
	 this copy because demangling needs a nullterminated string.  */
      std::string_view linkage_name_copy;
      if (copy_name)
	{
	  char *alloc_name = (char *) alloca (linkage_name.length () + 1);
	  memcpy (alloc_name, linkage_name.data (), linkage_name.length ());
	  alloc_name[linkage_name.length ()] = '\0';

	  linkage_name_copy = std::string_view (alloc_name,
						linkage_name.length ());
	}
      else
	linkage_name_copy = linkage_name;

      if (demangled_name.get () == nullptr)
	 demangled_name
	   = symbol_find_demangled_name (this, linkage_name_copy.data ());

      /* Suppose we have demangled_name==NULL, copy_name==0, and
	 linkage_name_copy==linkage_name.  In this case, we already have the
	 mangled name saved, and we don't have a demangled name.  So,
	 you might think we could save a little space by not recording
	 this in the hash table at all.

	 It turns out that it is actually important to still save such
	 an entry in the hash table, because storing this name gives
	 us better bcache hit rates for partial symbols.  */
      if (!copy_name)
	{
	  *slot
	    = ((struct demangled_name_entry *)
	       obstack_alloc (&per_bfd->storage_obstack,
			      sizeof (demangled_name_entry)));
	  new (*slot) demangled_name_entry (linkage_name);
	}
      else
	{
	  /* If we must copy the mangled name, put it directly after
	     the struct so we can have a single allocation.  */
	  *slot
	    = ((struct demangled_name_entry *)
	       obstack_alloc (&per_bfd->storage_obstack,
			      sizeof (demangled_name_entry)
			      + linkage_name.length () + 1));
	  char *mangled_ptr = reinterpret_cast<char *> (*slot + 1);
	  memcpy (mangled_ptr, linkage_name.data (), linkage_name.length ());
	  mangled_ptr [linkage_name.length ()] = '\0';
	  new (*slot) demangled_name_entry
	    (std::string_view (mangled_ptr, linkage_name.length ()));
	}
      (*slot)->demangled = std::move (demangled_name);
      (*slot)->language = language ();
    }
  else if (language () == language_unknown)
    m_language = (*slot)->language;

  m_name = (*slot)->mangled.data ();
  set_demangled_name ((*slot)->demangled.get (), &per_bfd->storage_obstack);
}

/* See symtab.h.  */

const char *
general_symbol_info::natural_name () const
{
  switch (language ())
    {
    case language_cplus:
    case language_d:
    case language_go:
    case language_objc:
    case language_fortran:
    case language_rust:
      if (language_specific.demangled_name != nullptr)
	return language_specific.demangled_name;
      break;
    case language_ada:
      return ada_decode_symbol (this);
    default:
      break;
    }
  return linkage_name ();
}

/* See symtab.h.  */

const char *
general_symbol_info::demangled_name () const
{
  const char *dem_name = NULL;

  switch (language ())
    {
    case language_cplus:
    case language_d:
    case language_go:
    case language_objc:
    case language_fortran:
    case language_rust:
      dem_name = language_specific.demangled_name;
      break;
    case language_ada:
      dem_name = ada_decode_symbol (this);
      break;
    default:
      break;
    }
  return dem_name;
}

/* See symtab.h.  */

const char *
general_symbol_info::search_name () const
{
  if (language () == language_ada)
    return linkage_name ();
  else
    return natural_name ();
}

/* See symtab.h.  */

struct obj_section *
general_symbol_info::obj_section (const struct objfile *objfile) const
{
  if (section_index () >= 0)
    return &objfile->sections_start[section_index ()];
  return nullptr;
}

/* See symtab.h.  */

bool
symbol_matches_search_name (const struct general_symbol_info *gsymbol,
			    const lookup_name_info &name)
{
  symbol_name_matcher_ftype *name_match
    = language_def (gsymbol->language ())->get_symbol_name_matcher (name);
  return name_match (gsymbol->search_name (), name, NULL);
}



/* Return true if the two sections are the same, or if they could
   plausibly be copies of each other, one in an original object
   file and another in a separated debug file.  */

bool
matching_obj_sections (struct obj_section *obj_first,
		       struct obj_section *obj_second)
{
  asection *first = obj_first? obj_first->the_bfd_section : NULL;
  asection *second = obj_second? obj_second->the_bfd_section : NULL;

  /* If they're the same section, then they match.  */
  if (first == second)
    return true;

  /* If either is NULL, give up.  */
  if (first == NULL || second == NULL)
    return false;

  /* This doesn't apply to absolute symbols.  */
  if (first->owner == NULL || second->owner == NULL)
    return false;

  /* If they're in the same object file, they must be different sections.  */
  if (first->owner == second->owner)
    return false;

  /* Check whether the two sections are potentially corresponding.  They must
     have the same size, address, and name.  We can't compare section indexes,
     which would be more reliable, because some sections may have been
     stripped.  */
  if (bfd_section_size (first) != bfd_section_size (second))
    return false;

  /* In-memory addresses may start at a different offset, relativize them.  */
  if (bfd_section_vma (first) - bfd_get_start_address (first->owner)
      != bfd_section_vma (second) - bfd_get_start_address (second->owner))
    return false;

  if (bfd_section_name (first) == NULL
      || bfd_section_name (second) == NULL
      || strcmp (bfd_section_name (first), bfd_section_name (second)) != 0)
    return false;

  /* Otherwise check that they are in corresponding objfiles.  */

  struct objfile *obj = NULL;
  for (objfile *objfile : current_program_space->objfiles ())
    if (objfile->obfd == first->owner)
      {
	obj = objfile;
	break;
      }
  gdb_assert (obj != NULL);

  if (obj->separate_debug_objfile != NULL
      && obj->separate_debug_objfile->obfd == second->owner)
    return true;
  if (obj->separate_debug_objfile_backlink != NULL
      && obj->separate_debug_objfile_backlink->obfd == second->owner)
    return true;

  return false;
}

/* Hash function for the symbol cache.  */

static unsigned int
hash_symbol_entry (const struct objfile *objfile_context,
		   const char *name, domain_search_flags domain)
{
  unsigned int hash = (uintptr_t) objfile_context;

  if (name != NULL)
    hash += htab_hash_string (name);

  hash += domain * 7;

  return hash;
}

/* Equality function for the symbol cache.  */

static int
eq_symbol_entry (const struct symbol_cache_slot *slot,
		 const struct objfile *objfile_context,
		 const char *name, domain_search_flags domain)
{
  const char *slot_name;

  if (slot->state == SYMBOL_SLOT_UNUSED)
    return 0;

  if (slot->objfile_context != objfile_context)
    return 0;

  domain_search_flags slot_domain = slot->domain;
  if (slot->state == SYMBOL_SLOT_NOT_FOUND)
    slot_name = slot->value.name;
  else
    slot_name = slot->value.found.symbol->search_name ();

  /* NULL names match.  */
  if (slot_name == NULL && name == NULL)
    {
      /* But there's no point in calling symbol_matches_domain in the
	 SYMBOL_SLOT_FOUND case.  */
      if (slot_domain != domain)
	return 0;
    }
  else if (slot_name != NULL && name != NULL)
    {
      /* It's important that we use the same comparison that was done
	 the first time through.  If the slot records a found symbol,
	 then this means using the symbol name comparison function of
	 the symbol's language with symbol->search_name ().  See
	 dictionary.c.

	 If the slot records a not-found symbol, then require a precise match.
	 We could still be lax with whitespace like strcmp_iw though.  */

      if (slot_domain != domain)
	return 0;

      if (slot->state == SYMBOL_SLOT_NOT_FOUND)
	{
	  if (strcmp (slot_name, name) != 0)
	    return 0;
	}
      else
	{
	  struct symbol *sym = slot->value.found.symbol;
	  lookup_name_info lookup_name (name, symbol_name_match_type::FULL);

	  if (!symbol_matches_search_name (sym, lookup_name))
	    return 0;
	}
    }
  else
    {
      /* Only one name is NULL.  */
      return 0;
    }

  return 1;
}

/* Given a cache of size SIZE, return the size of the struct (with variable
   length array) in bytes.  */

static size_t
symbol_cache_byte_size (unsigned int size)
{
  return (sizeof (struct block_symbol_cache)
	  + ((size - 1) * sizeof (struct symbol_cache_slot)));
}

/* Resize CACHE.  */

static void
resize_symbol_cache (struct symbol_cache *cache, unsigned int new_size)
{
  /* If there's no change in size, don't do anything.
     All caches have the same size, so we can just compare with the size
     of the global symbols cache.  */
  if ((cache->global_symbols != NULL
       && cache->global_symbols->size == new_size)
      || (cache->global_symbols == NULL
	  && new_size == 0))
    return;

  destroy_block_symbol_cache (cache->global_symbols);
  destroy_block_symbol_cache (cache->static_symbols);

  if (new_size == 0)
    {
      cache->global_symbols = NULL;
      cache->static_symbols = NULL;
    }
  else
    {
      size_t total_size = symbol_cache_byte_size (new_size);

      cache->global_symbols
	= (struct block_symbol_cache *) xcalloc (1, total_size);
      cache->static_symbols
	= (struct block_symbol_cache *) xcalloc (1, total_size);
      cache->global_symbols->size = new_size;
      cache->static_symbols->size = new_size;
    }
}

/* Return the symbol cache of PSPACE.
   Create one if it doesn't exist yet.  */

static struct symbol_cache *
get_symbol_cache (struct program_space *pspace)
{
  struct symbol_cache *cache = symbol_cache_key.get (pspace);

  if (cache == NULL)
    {
      cache = symbol_cache_key.emplace (pspace);
      resize_symbol_cache (cache, symbol_cache_size);
    }

  return cache;
}

/* Set the size of the symbol cache in all program spaces.  */

static void
set_symbol_cache_size (unsigned int new_size)
{
  for (struct program_space *pspace : program_spaces)
    {
      struct symbol_cache *cache = symbol_cache_key.get (pspace);

      /* The pspace could have been created but not have a cache yet.  */
      if (cache != NULL)
	resize_symbol_cache (cache, new_size);
    }
}

/* Called when symbol-cache-size is set.  */

static void
set_symbol_cache_size_handler (const char *args, int from_tty,
			       struct cmd_list_element *c)
{
  if (new_symbol_cache_size > MAX_SYMBOL_CACHE_SIZE)
    {
      /* Restore the previous value.
	 This is the value the "show" command prints.  */
      new_symbol_cache_size = symbol_cache_size;

      error (_("Symbol cache size is too large, max is %u."),
	     MAX_SYMBOL_CACHE_SIZE);
    }
  symbol_cache_size = new_symbol_cache_size;

  set_symbol_cache_size (symbol_cache_size);
}

/* Lookup symbol NAME,DOMAIN in BLOCK in the symbol cache of PSPACE.
   OBJFILE_CONTEXT is the current objfile, which may be NULL.
   The result is the symbol if found, SYMBOL_LOOKUP_FAILED if a previous lookup
   failed (and thus this one will too), or NULL if the symbol is not present
   in the cache.
   *BSC_PTR and *SLOT_PTR are set to the cache and slot of the symbol, which
   can be used to save the result of a full lookup attempt.  */

static struct block_symbol
symbol_cache_lookup (struct symbol_cache *cache,
		     struct objfile *objfile_context, enum block_enum block,
		     const char *name, domain_search_flags domain,
		     struct block_symbol_cache **bsc_ptr,
		     struct symbol_cache_slot **slot_ptr)
{
  struct block_symbol_cache *bsc;
  unsigned int hash;
  struct symbol_cache_slot *slot;

  if (block == GLOBAL_BLOCK)
    bsc = cache->global_symbols;
  else
    bsc = cache->static_symbols;
  if (bsc == NULL)
    {
      *bsc_ptr = NULL;
      *slot_ptr = NULL;
      return {};
    }

  hash = hash_symbol_entry (objfile_context, name, domain);
  slot = bsc->symbols + hash % bsc->size;

  *bsc_ptr = bsc;
  *slot_ptr = slot;

  if (eq_symbol_entry (slot, objfile_context, name, domain))
    {
      symbol_lookup_debug_printf ("%s block symbol cache hit%s for %s, %s",
				  block == GLOBAL_BLOCK ? "Global" : "Static",
				  slot->state == SYMBOL_SLOT_NOT_FOUND
				  ? " (not found)" : "", name,
				  domain_name (domain).c_str ());
      ++bsc->hits;
      if (slot->state == SYMBOL_SLOT_NOT_FOUND)
	return SYMBOL_LOOKUP_FAILED;
      return slot->value.found;
    }

  /* Symbol is not present in the cache.  */

  symbol_lookup_debug_printf ("%s block symbol cache miss for %s, %s",
			      block == GLOBAL_BLOCK ? "Global" : "Static",
			      name, domain_name (domain).c_str ());
  ++bsc->misses;
  return {};
}

/* Mark SYMBOL as found in SLOT.
   OBJFILE_CONTEXT is the current objfile when the lookup was done, or NULL
   if it's not needed to distinguish lookups (STATIC_BLOCK).  It is *not*
   necessarily the objfile the symbol was found in.  */

static void
symbol_cache_mark_found (struct block_symbol_cache *bsc,
			 struct symbol_cache_slot *slot,
			 struct objfile *objfile_context,
			 struct symbol *symbol,
			 const struct block *block,
			 domain_search_flags domain)
{
  if (bsc == NULL)
    return;
  if (slot->state != SYMBOL_SLOT_UNUSED)
    {
      ++bsc->collisions;
      symbol_cache_clear_slot (slot);
    }
  slot->state = SYMBOL_SLOT_FOUND;
  slot->objfile_context = objfile_context;
  slot->value.found.symbol = symbol;
  slot->value.found.block = block;
  slot->domain = domain;
}

/* Mark symbol NAME, DOMAIN as not found in SLOT.
   OBJFILE_CONTEXT is the current objfile when the lookup was done, or NULL
   if it's not needed to distinguish lookups (STATIC_BLOCK).  */

static void
symbol_cache_mark_not_found (struct block_symbol_cache *bsc,
			     struct symbol_cache_slot *slot,
			     struct objfile *objfile_context,
			     const char *name, domain_search_flags domain)
{
  if (bsc == NULL)
    return;
  if (slot->state != SYMBOL_SLOT_UNUSED)
    {
      ++bsc->collisions;
      symbol_cache_clear_slot (slot);
    }
  slot->state = SYMBOL_SLOT_NOT_FOUND;
  slot->objfile_context = objfile_context;
  slot->value.name = xstrdup (name);
  slot->domain = domain;
}

/* Flush the symbol cache of PSPACE.  */

static void
symbol_cache_flush (struct program_space *pspace)
{
  ada_clear_symbol_cache (pspace);
  struct symbol_cache *cache = symbol_cache_key.get (pspace);
  int pass;

  if (cache == NULL)
    return;
  if (cache->global_symbols == NULL)
    {
      gdb_assert (symbol_cache_size == 0);
      gdb_assert (cache->static_symbols == NULL);
      return;
    }

  /* If the cache is untouched since the last flush, early exit.
     This is important for performance during the startup of a program linked
     with 100s (or 1000s) of shared libraries.  */
  if (cache->global_symbols->misses == 0
      && cache->static_symbols->misses == 0)
    return;

  gdb_assert (cache->global_symbols->size == symbol_cache_size);
  gdb_assert (cache->static_symbols->size == symbol_cache_size);

  for (pass = 0; pass < 2; ++pass)
    {
      struct block_symbol_cache *bsc
	= pass == 0 ? cache->global_symbols : cache->static_symbols;
      unsigned int i;

      for (i = 0; i < bsc->size; ++i)
	symbol_cache_clear_slot (&bsc->symbols[i]);
    }

  cache->global_symbols->hits = 0;
  cache->global_symbols->misses = 0;
  cache->global_symbols->collisions = 0;
  cache->static_symbols->hits = 0;
  cache->static_symbols->misses = 0;
  cache->static_symbols->collisions = 0;
}

/* Dump CACHE.  */

static void
symbol_cache_dump (const struct symbol_cache *cache)
{
  int pass;

  if (cache->global_symbols == NULL)
    {
      gdb_printf ("  <disabled>\n");
      return;
    }

  for (pass = 0; pass < 2; ++pass)
    {
      const struct block_symbol_cache *bsc
	= pass == 0 ? cache->global_symbols : cache->static_symbols;
      unsigned int i;

      if (pass == 0)
	gdb_printf ("Global symbols:\n");
      else
	gdb_printf ("Static symbols:\n");

      for (i = 0; i < bsc->size; ++i)
	{
	  const struct symbol_cache_slot *slot = &bsc->symbols[i];

	  QUIT;

	  switch (slot->state)
	    {
	    case SYMBOL_SLOT_UNUSED:
	      break;
	    case SYMBOL_SLOT_NOT_FOUND:
	      gdb_printf ("  [%4u] = %s, %s %s (not found)\n", i,
			  host_address_to_string (slot->objfile_context),
			  slot->value.name,
			  domain_name (slot->domain).c_str ());
	      break;
	    case SYMBOL_SLOT_FOUND:
	      {
		struct symbol *found = slot->value.found.symbol;
		const struct objfile *context = slot->objfile_context;

		gdb_printf ("  [%4u] = %s, %s %s\n", i,
			    host_address_to_string (context),
			    found->print_name (),
			    domain_name (found->domain ()));
		break;
	      }
	    }
	}
    }
}

/* The "mt print symbol-cache" command.  */

static void
maintenance_print_symbol_cache (const char *args, int from_tty)
{
  for (struct program_space *pspace : program_spaces)
    {
      struct symbol_cache *cache;

      gdb_printf (_("Symbol cache for pspace %d\n%s:\n"),
		  pspace->num,
		  pspace->symfile_object_file != NULL
		  ? objfile_name (pspace->symfile_object_file)
		  : "(no object file)");

      /* If the cache hasn't been created yet, avoid creating one.  */
      cache = symbol_cache_key.get (pspace);
      if (cache == NULL)
	gdb_printf ("  <empty>\n");
      else
	symbol_cache_dump (cache);
    }
}

/* The "mt flush-symbol-cache" command.  */

static void
maintenance_flush_symbol_cache (const char *args, int from_tty)
{
  for (struct program_space *pspace : program_spaces)
    {
      symbol_cache_flush (pspace);
    }
}

/* Print usage statistics of CACHE.  */

static void
symbol_cache_stats (struct symbol_cache *cache)
{
  int pass;

  if (cache->global_symbols == NULL)
    {
      gdb_printf ("  <disabled>\n");
      return;
    }

  for (pass = 0; pass < 2; ++pass)
    {
      const struct block_symbol_cache *bsc
	= pass == 0 ? cache->global_symbols : cache->static_symbols;

      QUIT;

      if (pass == 0)
	gdb_printf ("Global block cache stats:\n");
      else
	gdb_printf ("Static block cache stats:\n");

      gdb_printf ("  size:       %u\n", bsc->size);
      gdb_printf ("  hits:       %u\n", bsc->hits);
      gdb_printf ("  misses:     %u\n", bsc->misses);
      gdb_printf ("  collisions: %u\n", bsc->collisions);
    }
}

/* The "mt print symbol-cache-statistics" command.  */

static void
maintenance_print_symbol_cache_statistics (const char *args, int from_tty)
{
  for (struct program_space *pspace : program_spaces)
    {
      struct symbol_cache *cache;

      gdb_printf (_("Symbol cache statistics for pspace %d\n%s:\n"),
		  pspace->num,
		  pspace->symfile_object_file != NULL
		  ? objfile_name (pspace->symfile_object_file)
		  : "(no object file)");

      /* If the cache hasn't been created yet, avoid creating one.  */
      cache = symbol_cache_key.get (pspace);
      if (cache == NULL)
	gdb_printf ("  empty, no stats available\n");
      else
	symbol_cache_stats (cache);
    }
}

/* This module's 'new_objfile' observer.  */

static void
symtab_new_objfile_observer (struct objfile *objfile)
{
  symbol_cache_flush (objfile->pspace ());
}

/* This module's 'all_objfiles_removed' observer.  */

static void
symtab_all_objfiles_removed (program_space *pspace)
{
  symbol_cache_flush (pspace);

  /* Forget everything we know about the main function.  */
  set_main_name (pspace, nullptr, language_unknown);
}

/* This module's 'free_objfile' observer.  */

static void
symtab_free_objfile_observer (struct objfile *objfile)
{
  symbol_cache_flush (objfile->pspace ());
}

/* See symtab.h.  */

void
fixup_symbol_section (struct symbol *sym, struct objfile *objfile)
{
  gdb_assert (sym != nullptr);
  gdb_assert (sym->is_objfile_owned ());
  gdb_assert (objfile != nullptr);
  gdb_assert (sym->section_index () == -1);

  /* Note that if this ends up as -1, fixup_section will handle that
     reasonably well.  So, it's fine to use the objfile's section
     index without doing the check that is done by the wrapper macros
     like SECT_OFF_TEXT.  */
  int fallback;
  switch (sym->aclass ())
    {
    case LOC_STATIC:
      fallback = objfile->sect_index_data;
      break;

    case LOC_LABEL:
      fallback = objfile->sect_index_text;
      break;

    default:
      /* Nothing else will be listed in the minsyms -- no use looking
	 it up.  */
      return;
    }

  CORE_ADDR addr = sym->value_address ();

  struct minimal_symbol *msym;

  /* First, check whether a minimal symbol with the same name exists
     and points to the same address.  The address check is required
     e.g. on PowerPC64, where the minimal symbol for a function will
     point to the function descriptor, while the debug symbol will
     point to the actual function code.  */
  msym = lookup_minimal_symbol_by_pc_name (addr, sym->linkage_name (),
					   objfile);
  if (msym)
    sym->set_section_index (msym->section_index ());
  else
    {
      /* Static, function-local variables do appear in the linker
	 (minimal) symbols, but are frequently given names that won't
	 be found via lookup_minimal_symbol().  E.g., it has been
	 observed in frv-uclinux (ELF) executables that a static,
	 function-local variable named "foo" might appear in the
	 linker symbols as "foo.6" or "foo.3".  Thus, there is no
	 point in attempting to extend the lookup-by-name mechanism to
	 handle this case due to the fact that there can be multiple
	 names.

	 So, instead, search the section table when lookup by name has
	 failed.  The ``addr'' and ``endaddr'' fields may have already
	 been relocated.  If so, the relocation offset needs to be
	 subtracted from these values when performing the comparison.
	 We unconditionally subtract it, because, when no relocation
	 has been performed, the value will simply be zero.

	 The address of the symbol whose section we're fixing up HAS
	 NOT BEEN adjusted (relocated) yet.  It can't have been since
	 the section isn't yet known and knowing the section is
	 necessary in order to add the correct relocation value.  In
	 other words, we wouldn't even be in this function (attempting
	 to compute the section) if it were already known.

	 Note that it is possible to search the minimal symbols
	 (subtracting the relocation value if necessary) to find the
	 matching minimal symbol, but this is overkill and much less
	 efficient.  It is not necessary to find the matching minimal
	 symbol, only its section.

	 Note that this technique (of doing a section table search)
	 can fail when unrelocated section addresses overlap.  For
	 this reason, we still attempt a lookup by name prior to doing
	 a search of the section table.  */

      for (obj_section *s : objfile->sections ())
	{
	  if ((bfd_section_flags (s->the_bfd_section) & SEC_ALLOC) == 0)
	    continue;

	  int idx = s - objfile->sections_start;
	  CORE_ADDR offset = objfile->section_offsets[idx];

	  if (fallback == -1)
	    fallback = idx;

	  if (s->addr () - offset <= addr && addr < s->endaddr () - offset)
	    {
	      sym->set_section_index (idx);
	      return;
	    }
	}

      /* If we didn't find the section, assume it is in the first
	 section.  If there is no allocated section, then it hardly
	 matters what we pick, so just pick zero.  */
      if (fallback == -1)
	sym->set_section_index (0);
      else
	sym->set_section_index (fallback);
    }
}

/* See symtab.h.  */

demangle_for_lookup_info::demangle_for_lookup_info
  (const lookup_name_info &lookup_name, language lang)
{
  demangle_result_storage storage;

  if (lookup_name.ignore_parameters () && lang == language_cplus)
    {
      gdb::unique_xmalloc_ptr<char> without_params
	= cp_remove_params_if_any (lookup_name.c_str (),
				   lookup_name.completion_mode ());

      if (without_params != NULL)
	{
	  if (lookup_name.match_type () != symbol_name_match_type::SEARCH_NAME)
	    m_demangled_name = demangle_for_lookup (without_params.get (),
						    lang, storage);
	  return;
	}
    }

  if (lookup_name.match_type () == symbol_name_match_type::SEARCH_NAME)
    m_demangled_name = lookup_name.c_str ();
  else
    m_demangled_name = demangle_for_lookup (lookup_name.c_str (),
					    lang, storage);
}

/* See symtab.h.  */

const lookup_name_info &
lookup_name_info::match_any ()
{
  /* Lookup any symbol that "" would complete.  I.e., this matches all
     symbol names.  */
  static const lookup_name_info lookup_name ("", symbol_name_match_type::FULL,
					     true);

  return lookup_name;
}

/* See symtab.h.  */

unsigned int
lookup_name_info::search_name_hash (language lang) const
{
  /* This works around an obscure problem.  If currently in Ada mode,
     and the name is wrapped in '<...>' (indicating verbatim mode),
     force the use of the Ada language here so that the '<' and '>'
     will be removed.  */
  if (current_language->la_language == language_ada && ada ().verbatim_p ())
    lang = language_ada;

  /* Only compute each language's hash once.  */
  if (!m_demangled_hashes_p[lang])
    {
      m_demangled_hashes[lang]
	= ::search_name_hash (lang, language_lookup_name (lang));
      m_demangled_hashes_p[lang] = true;
    }
  return m_demangled_hashes[lang];
}

/* Compute the demangled form of NAME as used by the various symbol
   lookup functions.  The result can either be the input NAME
   directly, or a pointer to a buffer owned by the STORAGE object.

   For Ada, this function just returns NAME, unmodified.
   Normally, Ada symbol lookups are performed using the encoded name
   rather than the demangled name, and so it might seem to make sense
   for this function to return an encoded version of NAME.
   Unfortunately, we cannot do this, because this function is used in
   circumstances where it is not appropriate to try to encode NAME.
   For instance, when displaying the frame info, we demangle the name
   of each parameter, and then perform a symbol lookup inside our
   function using that demangled name.  In Ada, certain functions
   have internally-generated parameters whose name contain uppercase
   characters.  Encoding those name would result in those uppercase
   characters to become lowercase, and thus cause the symbol lookup
   to fail.  */

const char *
demangle_for_lookup (const char *name, enum language lang,
		     demangle_result_storage &storage)
{
  /* If we are using C++, D, or Go, demangle the name before doing a
     lookup, so we can always binary search.  */
  if (lang == language_cplus)
    {
      gdb::unique_xmalloc_ptr<char> demangled_name
	= gdb_demangle (name, DMGL_ANSI | DMGL_PARAMS);
      if (demangled_name != NULL)
	return storage.set_malloc_ptr (std::move (demangled_name));

      /* If we were given a non-mangled name, canonicalize it
	 according to the language (so far only for C++).  */
      gdb::unique_xmalloc_ptr<char> canon = cp_canonicalize_string (name);
      if (canon != nullptr)
	return storage.set_malloc_ptr (std::move (canon));
    }
  else if (lang == language_d)
    {
      gdb::unique_xmalloc_ptr<char> demangled_name = d_demangle (name, 0);
      if (demangled_name != NULL)
	return storage.set_malloc_ptr (std::move (demangled_name));
    }
  else if (lang == language_go)
    {
      gdb::unique_xmalloc_ptr<char> demangled_name
	= language_def (language_go)->demangle_symbol (name, 0);
      if (demangled_name != NULL)
	return storage.set_malloc_ptr (std::move (demangled_name));
    }

  return name;
}

/* See symtab.h.  */

unsigned int
search_name_hash (enum language language, const char *search_name)
{
  return language_def (language)->search_name_hash (search_name);
}

/* See symtab.h.

   This function (or rather its subordinates) have a bunch of loops and
   it would seem to be attractive to put in some QUIT's (though I'm not really
   sure whether it can run long enough to be really important).  But there
   are a few calls for which it would appear to be bad news to quit
   out of here: e.g., find_proc_desc in alpha-mdebug-tdep.c.  (Note
   that there is C++ code below which can error(), but that probably
   doesn't affect these calls since they are looking for a known
   variable and thus can probably assume it will never hit the C++
   code).  */

struct block_symbol
lookup_symbol_in_language (const char *name, const struct block *block,
			   const domain_search_flags domain,
			   enum language lang,
			   struct field_of_this_result *is_a_field_of_this)
{
  SYMBOL_LOOKUP_SCOPED_DEBUG_ENTER_EXIT;

  demangle_result_storage storage;
  const char *modified_name = demangle_for_lookup (name, lang, storage);

  return lookup_symbol_aux (modified_name,
			    symbol_name_match_type::FULL,
			    block, domain, lang,
			    is_a_field_of_this);
}

/* See symtab.h.  */

struct block_symbol
lookup_symbol (const char *name, const struct block *block,
	       domain_search_flags domain,
	       struct field_of_this_result *is_a_field_of_this)
{
  return lookup_symbol_in_language (name, block, domain,
				    current_language->la_language,
				    is_a_field_of_this);
}

/* See symtab.h.  */

struct block_symbol
lookup_symbol_search_name (const char *search_name, const struct block *block,
			   domain_search_flags domain)
{
  return lookup_symbol_aux (search_name, symbol_name_match_type::SEARCH_NAME,
			    block, domain, language_asm, NULL);
}

/* See symtab.h.  */

struct block_symbol
lookup_language_this (const struct language_defn *lang,
		      const struct block *block)
{
  if (lang->name_of_this () == NULL || block == NULL)
    return {};

  symbol_lookup_debug_printf_v ("lookup_language_this (%s, %s (objfile %s))",
				lang->name (), host_address_to_string (block),
				objfile_debug_name (block->objfile ()));

  lookup_name_info this_name (lang->name_of_this (),
			      symbol_name_match_type::SEARCH_NAME);

  while (block)
    {
      struct symbol *sym;

      sym = block_lookup_symbol (block, this_name, SEARCH_VFT);
      if (sym != NULL)
	{
	  symbol_lookup_debug_printf_v
	    ("lookup_language_this (...) = %s (%s, block %s)",
	     sym->print_name (), host_address_to_string (sym),
	     host_address_to_string (block));
	  return (struct block_symbol) {sym, block};
	}
      if (block->function ())
	break;
      block = block->superblock ();
    }

  symbol_lookup_debug_printf_v ("lookup_language_this (...) = NULL");
  return {};
}

/* Given TYPE, a structure/union,
   return 1 if the component named NAME from the ultimate target
   structure/union is defined, otherwise, return 0.  */

static int
check_field (struct type *type, const char *name,
	     struct field_of_this_result *is_a_field_of_this)
{
  int i;

  /* The type may be a stub.  */
  type = check_typedef (type);

  for (i = type->num_fields () - 1; i >= TYPE_N_BASECLASSES (type); i--)
    {
      const char *t_field_name = type->field (i).name ();

      if (t_field_name && (strcmp_iw (t_field_name, name) == 0))
	{
	  is_a_field_of_this->type = type;
	  is_a_field_of_this->field = &type->field (i);
	  return 1;
	}
    }

  /* C++: If it was not found as a data field, then try to return it
     as a pointer to a method.  */

  for (i = TYPE_NFN_FIELDS (type) - 1; i >= 0; --i)
    {
      if (strcmp_iw (TYPE_FN_FIELDLIST_NAME (type, i), name) == 0)
	{
	  is_a_field_of_this->type = type;
	  is_a_field_of_this->fn_field = &TYPE_FN_FIELDLIST (type, i);
	  return 1;
	}
    }

  for (i = TYPE_N_BASECLASSES (type) - 1; i >= 0; i--)
    if (check_field (TYPE_BASECLASS (type, i), name, is_a_field_of_this))
      return 1;

  return 0;
}

/* Behave like lookup_symbol except that NAME is the natural name
   (e.g., demangled name) of the symbol that we're looking for.  */

static struct block_symbol
lookup_symbol_aux (const char *name, symbol_name_match_type match_type,
		   const struct block *block,
		   const domain_search_flags domain, enum language language,
		   struct field_of_this_result *is_a_field_of_this)
{
  SYMBOL_LOOKUP_SCOPED_DEBUG_ENTER_EXIT;

  struct block_symbol result;
  const struct language_defn *langdef;

  if (symbol_lookup_debug)
    {
      struct objfile *objfile = (block == nullptr
				 ? nullptr : block->objfile ());

      symbol_lookup_debug_printf
	("demangled symbol name = \"%s\", block @ %s (objfile %s)",
	 name, host_address_to_string (block),
	 objfile != NULL ? objfile_debug_name (objfile) : "NULL");
      symbol_lookup_debug_printf
	("domain name = \"%s\", language = \"%s\")",
	 domain_name (domain).c_str (), language_str (language));
    }

  /* Make sure we do something sensible with is_a_field_of_this, since
     the callers that set this parameter to some non-null value will
     certainly use it later.  If we don't set it, the contents of
     is_a_field_of_this are undefined.  */
  if (is_a_field_of_this != NULL)
    memset (is_a_field_of_this, 0, sizeof (*is_a_field_of_this));

  langdef = language_def (language);

  /* Search specified block and its superiors.  Don't search
     STATIC_BLOCK or GLOBAL_BLOCK.  */

  result = lookup_local_symbol (name, match_type, block, domain, langdef);
  if (result.symbol != NULL)
    {
      symbol_lookup_debug_printf
	("found symbol @ %s (using lookup_local_symbol)",
	 host_address_to_string (result.symbol));
      return result;
    }

  /* If requested to do so by the caller and if appropriate for LANGUAGE,
     check to see if NAME is a field of `this'.  */

  /* Don't do this check if we are searching for a struct.  It will
     not be found by check_field, but will be found by other
     means.  */
  if (is_a_field_of_this != NULL && (domain & SEARCH_STRUCT_DOMAIN) == 0)
    {
      result = lookup_language_this (langdef, block);

      if (result.symbol)
	{
	  struct type *t = result.symbol->type ();

	  /* I'm not really sure that type of this can ever
	     be typedefed; just be safe.  */
	  t = check_typedef (t);
	  if (t->is_pointer_or_reference ())
	    t = t->target_type ();

	  if (t->code () != TYPE_CODE_STRUCT
	      && t->code () != TYPE_CODE_UNION)
	    error (_("Internal error: `%s' is not an aggregate"),
		   langdef->name_of_this ());

	  if (check_field (t, name, is_a_field_of_this))
	    {
	      symbol_lookup_debug_printf ("no symbol found");
	      return {};
	    }
	}
    }

  /* Now do whatever is appropriate for LANGUAGE to look
     up static and global variables.  */

  result = langdef->lookup_symbol_nonlocal (name, block, domain);
  if (result.symbol != NULL)
    {
      symbol_lookup_debug_printf
	("found symbol @ %s (using language lookup_symbol_nonlocal)",
	 host_address_to_string (result.symbol));
      return result;
    }

  /* Now search all static file-level symbols.  Not strictly correct,
     but more useful than an error.  */

  result = lookup_static_symbol (name, domain);
  symbol_lookup_debug_printf
    ("found symbol @ %s (using lookup_static_symbol)",
     result.symbol != NULL ? host_address_to_string (result.symbol) : "NULL");
  return result;
}

/* Check to see if the symbol is defined in BLOCK or its superiors.
   Don't search STATIC_BLOCK or GLOBAL_BLOCK.  */

static struct block_symbol
lookup_local_symbol (const char *name,
		     symbol_name_match_type match_type,
		     const struct block *block,
		     const domain_search_flags domain,
		     const struct language_defn *langdef)
{
  if (block == nullptr)
    return {};

  const char *scope = block->scope ();
  
  while (!block->is_global_block () && !block->is_static_block ())
    {
      struct symbol *sym = lookup_symbol_in_block (name, match_type,
						   block, domain);
      if (sym != NULL)
	return (struct block_symbol) {sym, block};

      struct symbol *function = block->function ();
      if (function != nullptr && function->is_template_function ())
	{
	  struct template_symbol *templ = (struct template_symbol *) function;
	  sym = search_symbol_list (name,
				    templ->n_template_arguments,
				    templ->template_arguments);
	  if (sym != nullptr)
	    return (struct block_symbol) {sym, block};
	}

      struct block_symbol blocksym
	= langdef->lookup_symbol_local (scope, name, block, domain);
      if (blocksym.symbol != nullptr)
	return blocksym;

      if (block->inlined_p ())
	break;
      block = block->superblock ();
    }

  /* We've reached the end of the function without finding a result.  */

  return {};
}

/* See symtab.h.  */

struct symbol *
lookup_symbol_in_block (const char *name, symbol_name_match_type match_type,
			const struct block *block,
			const domain_search_flags domain)
{
  struct symbol *sym;

  if (symbol_lookup_debug)
    {
      struct objfile *objfile
	= block == nullptr ? nullptr : block->objfile ();

      symbol_lookup_debug_printf_v
	("lookup_symbol_in_block (%s, %s (objfile %s), %s)",
	 name, host_address_to_string (block),
	 objfile != nullptr ? objfile_debug_name (objfile) : "NULL",
	 domain_name (domain).c_str ());
    }

  lookup_name_info lookup_name (name, match_type);
  sym = block_lookup_symbol (block, lookup_name, domain);
  if (sym)
    {
      symbol_lookup_debug_printf_v ("lookup_symbol_in_block (...) = %s",
				    host_address_to_string (sym));
      return sym;
    }

  symbol_lookup_debug_printf_v ("lookup_symbol_in_block (...) = NULL");
  return NULL;
}

/* See symtab.h.  */

struct block_symbol
lookup_global_symbol_from_objfile (struct objfile *main_objfile,
				   enum block_enum block_index,
				   const char *name,
				   const domain_search_flags domain)
{
  gdb_assert (block_index == GLOBAL_BLOCK || block_index == STATIC_BLOCK);

  for (objfile *objfile : main_objfile->separate_debug_objfiles ())
    {
      struct block_symbol result
	= lookup_symbol_in_objfile (objfile, block_index, name, domain);

      if (result.symbol != nullptr)
	return result;
    }

  return {};
}

/* Check to see if the symbol is defined in one of the OBJFILE's
   symtabs.  BLOCK_INDEX should be either GLOBAL_BLOCK or STATIC_BLOCK,
   depending on whether or not we want to search global symbols or
   static symbols.  */

static struct block_symbol
lookup_symbol_in_objfile_symtabs (struct objfile *objfile,
				  enum block_enum block_index, const char *name,
				  const domain_search_flags domain)
{
  gdb_assert (block_index == GLOBAL_BLOCK || block_index == STATIC_BLOCK);

  symbol_lookup_debug_printf_v
    ("lookup_symbol_in_objfile_symtabs (%s, %s, %s, %s)",
     objfile_debug_name (objfile),
     block_index == GLOBAL_BLOCK ? "GLOBAL_BLOCK" : "STATIC_BLOCK",
     name, domain_name (domain).c_str ());

  struct block_symbol other;
  other.symbol = NULL;
  for (compunit_symtab *cust : objfile->compunits ())
    {
      const struct blockvector *bv;
      const struct block *block;
      struct block_symbol result;

      bv = cust->blockvector ();
      block = bv->block (block_index);
      result.symbol = block_lookup_symbol_primary (block, name, domain);
      result.block = block;
      if (result.symbol == NULL)
	continue;
      if (best_symbol (result.symbol, domain))
	{
	  other = result;
	  break;
	}
      if (result.symbol->matches (domain))
	{
	  struct symbol *better
	    = better_symbol (other.symbol, result.symbol, domain);
	  if (better != other.symbol)
	    {
	      other.symbol = better;
	      other.block = block;
	    }
	}
    }

  if (other.symbol != NULL)
    {
      symbol_lookup_debug_printf_v
	("lookup_symbol_in_objfile_symtabs (...) = %s (block %s)",
	 host_address_to_string (other.symbol),
	 host_address_to_string (other.block));
      return other;
    }

  symbol_lookup_debug_printf_v
    ("lookup_symbol_in_objfile_symtabs (...) = NULL");
  return {};
}

/* Wrapper around lookup_symbol_in_objfile_symtabs for search_symbols.
   Look up LINKAGE_NAME in DOMAIN in the global and static blocks of OBJFILE
   and all associated separate debug objfiles.

   Normally we only look in OBJFILE, and not any separate debug objfiles
   because the outer loop will cause them to be searched too.  This case is
   different.  Here we're called from search_symbols where it will only
   call us for the objfile that contains a matching minsym.  */

static struct block_symbol
lookup_symbol_in_objfile_from_linkage_name (struct objfile *objfile,
					    const char *linkage_name,
					    domain_search_flags domain)
{
  enum language lang = current_language->la_language;
  struct objfile *main_objfile;

  demangle_result_storage storage;
  const char *modified_name = demangle_for_lookup (linkage_name, lang, storage);

  if (objfile->separate_debug_objfile_backlink)
    main_objfile = objfile->separate_debug_objfile_backlink;
  else
    main_objfile = objfile;

  for (::objfile *cur_objfile : main_objfile->separate_debug_objfiles ())
    {
      struct block_symbol result;

      result = lookup_symbol_in_objfile_symtabs (cur_objfile, GLOBAL_BLOCK,
						 modified_name, domain);
      if (result.symbol == NULL)
	result = lookup_symbol_in_objfile_symtabs (cur_objfile, STATIC_BLOCK,
						   modified_name, domain);
      if (result.symbol != NULL)
	return result;
    }

  return {};
}

/* A helper function that throws an exception when a symbol was found
   in a psymtab but not in a symtab.  */

[[noreturn]] static void
error_in_psymtab_expansion (enum block_enum block_index, const char *name,
			    struct compunit_symtab *cust)
{
  error (_("\
Internal: %s symbol `%s' found in %s psymtab but not in symtab.\n\
%s may be an inlined function, or may be a template function\n	 \
(if a template, try specifying an instantiation: %s<type>)."),
	 block_index == GLOBAL_BLOCK ? "global" : "static",
	 name,
	 symtab_to_filename_for_display (cust->primary_filetab ()),
	 name, name);
}

/* A helper function for various lookup routines that interfaces with
   the "quick" symbol table functions.  */

static struct block_symbol
lookup_symbol_via_quick_fns (struct objfile *objfile,
			     enum block_enum block_index, const char *name,
			     const domain_search_flags domain)
{
  struct compunit_symtab *cust;
  const struct blockvector *bv;
  const struct block *block;
  struct block_symbol result;

  symbol_lookup_debug_printf_v
    ("lookup_symbol_via_quick_fns (%s, %s, %s, %s)",
     objfile_debug_name (objfile),
     block_index == GLOBAL_BLOCK ? "GLOBAL_BLOCK" : "STATIC_BLOCK",
     name, domain_name (domain).c_str ());

  lookup_name_info lookup_name (name, symbol_name_match_type::FULL);
  cust = objfile->lookup_symbol (block_index, lookup_name, domain);
  if (cust == NULL)
    {
      symbol_lookup_debug_printf_v
	("lookup_symbol_via_quick_fns (...) = NULL");
      return {};
    }

  bv = cust->blockvector ();
  block = bv->block (block_index);
  result.symbol = block_lookup_symbol (block, lookup_name, domain);
  if (result.symbol == NULL)
    error_in_psymtab_expansion (block_index, name, cust);

  symbol_lookup_debug_printf_v
    ("lookup_symbol_via_quick_fns (...) = %s (block %s)",
     host_address_to_string (result.symbol),
     host_address_to_string (block));

  result.block = block;
  return result;
}

/* See language.h.  */

struct block_symbol
language_defn::lookup_symbol_nonlocal (const char *name,
				       const struct block *block,
				       const domain_search_flags domain) const
{
  struct block_symbol result;

  /* NOTE: dje/2014-10-26: The lookup in all objfiles search could skip
     the current objfile.  Searching the current objfile first is useful
     for both matching user expectations as well as performance.  */

  result = lookup_symbol_in_static_block (name, block, domain);
  if (result.symbol != NULL)
    return result;

  /* If we didn't find a definition for a builtin type in the static block,
     search for it now.  This is actually the right thing to do and can be
     a massive performance win.  E.g., when debugging a program with lots of
     shared libraries we could search all of them only to find out the
     builtin type isn't defined in any of them.  This is common for types
     like "void".  */
  if ((domain & SEARCH_TYPE_DOMAIN) != 0)
    {
      struct gdbarch *gdbarch;

      if (block == NULL)
	gdbarch = current_inferior ()->arch ();
      else
	gdbarch = block->gdbarch ();
      result.symbol = language_lookup_primitive_type_as_symbol (this,
								gdbarch, name);
      result.block = NULL;
      if (result.symbol != NULL)
	return result;
    }

  return lookup_global_symbol (name, block, domain);
}

/* See symtab.h.  */

struct block_symbol
lookup_symbol_in_static_block (const char *name,
			       const struct block *block,
			       const domain_search_flags domain)
{
  if (block == nullptr)
    return {};

  const struct block *static_block = block->static_block ();
  struct symbol *sym;

  if (static_block == NULL)
    return {};

  if (symbol_lookup_debug)
    {
      struct objfile *objfile = (block == nullptr
				 ? nullptr : block->objfile ());

      symbol_lookup_debug_printf
	("lookup_symbol_in_static_block (%s, %s (objfile %s), %s)",
	 name, host_address_to_string (block),
	 objfile != nullptr ? objfile_debug_name (objfile) : "NULL",
	 domain_name (domain).c_str ());
    }

  sym = lookup_symbol_in_block (name,
				symbol_name_match_type::FULL,
				static_block, domain);
  symbol_lookup_debug_printf ("lookup_symbol_in_static_block (...) = %s",
			      sym != NULL
			      ? host_address_to_string (sym) : "NULL");
  return (struct block_symbol) {sym, static_block};
}

/* Perform the standard symbol lookup of NAME in OBJFILE:
   1) First search expanded symtabs, and if not found
   2) Search the "quick" symtabs (partial or .gdb_index).
   BLOCK_INDEX is one of GLOBAL_BLOCK or STATIC_BLOCK.  */

static struct block_symbol
lookup_symbol_in_objfile (struct objfile *objfile, enum block_enum block_index,
			  const char *name, const domain_search_flags domain)
{
  struct block_symbol result;

  gdb_assert (block_index == GLOBAL_BLOCK || block_index == STATIC_BLOCK);

  symbol_lookup_debug_printf ("lookup_symbol_in_objfile (%s, %s, %s, %s)",
			      objfile_debug_name (objfile),
			      block_index == GLOBAL_BLOCK
			      ? "GLOBAL_BLOCK" : "STATIC_BLOCK",
			      name, domain_name (domain).c_str ());

  result = lookup_symbol_in_objfile_symtabs (objfile, block_index,
					     name, domain);
  if (result.symbol != NULL)
    {
      symbol_lookup_debug_printf
	("lookup_symbol_in_objfile (...) = %s (in symtabs)",
	 host_address_to_string (result.symbol));
      return result;
    }

  result = lookup_symbol_via_quick_fns (objfile, block_index,
					name, domain);
  symbol_lookup_debug_printf ("lookup_symbol_in_objfile (...) = %s%s",
			      result.symbol != NULL
			      ? host_address_to_string (result.symbol)
			      : "NULL",
			      result.symbol != NULL ? " (via quick fns)"
			      : "");
  return result;
}

/* This function contains the common code of lookup_{global,static}_symbol.
   OBJFILE is only used if BLOCK_INDEX is GLOBAL_SCOPE, in which case it is
   the objfile to start the lookup in.  */

static struct block_symbol
lookup_global_or_static_symbol (const char *name,
				enum block_enum block_index,
				struct objfile *objfile,
				const domain_search_flags domain)
{
  struct symbol_cache *cache = get_symbol_cache (current_program_space);
  struct block_symbol result;
  struct block_symbol_cache *bsc;
  struct symbol_cache_slot *slot;

  gdb_assert (block_index == GLOBAL_BLOCK || block_index == STATIC_BLOCK);
  gdb_assert (objfile == nullptr || block_index == GLOBAL_BLOCK);

  /* First see if we can find the symbol in the cache.
     This works because we use the current objfile to qualify the lookup.  */
  result = symbol_cache_lookup (cache, objfile, block_index, name, domain,
				&bsc, &slot);
  if (result.symbol != NULL)
    {
      if (SYMBOL_LOOKUP_FAILED_P (result))
	return {};
      return result;
    }

  /* Do a global search (of global blocks, heh).  */
  if (result.symbol == NULL)
    gdbarch_iterate_over_objfiles_in_search_order
      (objfile != NULL ? objfile->arch () : current_inferior ()->arch (),
       [&result, block_index, name, domain] (struct objfile *objfile_iter)
	 {
	   result = lookup_symbol_in_objfile (objfile_iter, block_index,
					      name, domain);
	   return result.symbol != nullptr;
	 },
       objfile);

  if (result.symbol != NULL)
    symbol_cache_mark_found (bsc, slot, objfile, result.symbol, result.block,
			     domain);
  else
    symbol_cache_mark_not_found (bsc, slot, objfile, name, domain);

  return result;
}

/* See symtab.h.  */

struct block_symbol
lookup_static_symbol (const char *name, const domain_search_flags domain)
{
  return lookup_global_or_static_symbol (name, STATIC_BLOCK, nullptr, domain);
}

/* See symtab.h.  */

struct block_symbol
lookup_global_symbol (const char *name,
		      const struct block *block,
		      const domain_search_flags domain)
{
  /* If a block was passed in, we want to search the corresponding
     global block first.  This yields "more expected" behavior, and is
     needed to support 'FILENAME'::VARIABLE lookups.  */
  const struct block *global_block
    = block == nullptr ? nullptr : block->global_block ();
  symbol *sym = NULL;
  if (global_block != nullptr)
    {
      sym = lookup_symbol_in_block (name,
				    symbol_name_match_type::FULL,
				    global_block, domain);
      if (sym != NULL && best_symbol (sym, domain))
	return { sym, global_block };
    }

  struct objfile *objfile = nullptr;
  if (block != nullptr)
    {
      objfile = block->objfile ();
      if (objfile->separate_debug_objfile_backlink != nullptr)
	objfile = objfile->separate_debug_objfile_backlink;
    }

  block_symbol bs
    = lookup_global_or_static_symbol (name, GLOBAL_BLOCK, objfile, domain);
  if (better_symbol (sym, bs.symbol, domain) == sym)
    return { sym, global_block };
  else
    return bs;
}

/* See symtab.h.  */

bool
symbol::matches (domain_search_flags flags) const
{
  /* C++ has a typedef for every tag, and the types are in the struct
     domain.  */
  if (language () == language_cplus && (flags & SEARCH_TYPE_DOMAIN) != 0)
    flags |= SEARCH_STRUCT_DOMAIN;

  return search_flags_matches (flags, m_domain);
}

/* See symtab.h.  */

struct type *
lookup_transparent_type (const char *name, domain_search_flags flags)
{
  return current_language->lookup_transparent_type (name, flags);
}

/* A helper for basic_lookup_transparent_type that interfaces with the
   "quick" symbol table functions.  */

static struct type *
basic_lookup_transparent_type_quick (struct objfile *objfile,
				     enum block_enum block_index,
				     domain_search_flags flags,
				     const lookup_name_info &name)
{
  struct compunit_symtab *cust;
  const struct blockvector *bv;
  const struct block *block;
  struct symbol *sym;

  cust = objfile->lookup_symbol (block_index, name, flags);
  if (cust == NULL)
    return NULL;

  bv = cust->blockvector ();
  block = bv->block (block_index);

  sym = block_find_symbol (block, name, flags, nullptr);
  if (sym == nullptr)
    error_in_psymtab_expansion (block_index, name.c_str (), cust);
  gdb_assert (!TYPE_IS_OPAQUE (sym->type ()));
  return sym->type ();
}

/* Subroutine of basic_lookup_transparent_type to simplify it.
   Look up the non-opaque definition of NAME in BLOCK_INDEX of OBJFILE.
   BLOCK_INDEX is either GLOBAL_BLOCK or STATIC_BLOCK.  */

static struct type *
basic_lookup_transparent_type_1 (struct objfile *objfile,
				 enum block_enum block_index,
				 domain_search_flags flags,
				 const lookup_name_info &name)
{
  const struct blockvector *bv;
  const struct block *block;
  const struct symbol *sym;

  for (compunit_symtab *cust : objfile->compunits ())
    {
      bv = cust->blockvector ();
      block = bv->block (block_index);
      sym = block_find_symbol (block, name, flags, nullptr);
      if (sym != nullptr)
	{
	  gdb_assert (!TYPE_IS_OPAQUE (sym->type ()));
	  return sym->type ();
	}
    }

  return NULL;
}

/* The standard implementation of lookup_transparent_type.  This code
   was modeled on lookup_symbol -- the parts not relevant to looking
   up types were just left out.  In particular it's assumed here that
   types are available in STRUCT_DOMAIN and only in file-static or
   global blocks.  */

struct type *
basic_lookup_transparent_type (const char *name, domain_search_flags flags)
{
  struct type *t;

  lookup_name_info lookup_name (name, symbol_name_match_type::FULL);

  /* Now search all the global symbols.  Do the symtab's first, then
     check the psymtab's.  If a psymtab indicates the existence
     of the desired name as a global, then do psymtab-to-symtab
     conversion on the fly and return the found symbol.  */

  for (objfile *objfile : current_program_space->objfiles ())
    {
      t = basic_lookup_transparent_type_1 (objfile, GLOBAL_BLOCK,
					   flags, lookup_name);
      if (t)
	return t;
    }

  for (objfile *objfile : current_program_space->objfiles ())
    {
      t = basic_lookup_transparent_type_quick (objfile, GLOBAL_BLOCK,
					       flags, lookup_name);
      if (t)
	return t;
    }

  /* Now search the static file-level symbols.
     Not strictly correct, but more useful than an error.
     Do the symtab's first, then
     check the psymtab's.  If a psymtab indicates the existence
     of the desired name as a file-level static, then do psymtab-to-symtab
     conversion on the fly and return the found symbol.  */

  for (objfile *objfile : current_program_space->objfiles ())
    {
      t = basic_lookup_transparent_type_1 (objfile, STATIC_BLOCK,
					   flags, lookup_name);
      if (t)
	return t;
    }

  for (objfile *objfile : current_program_space->objfiles ())
    {
      t = basic_lookup_transparent_type_quick (objfile, STATIC_BLOCK,
					       flags, lookup_name);
      if (t)
	return t;
    }

  return (struct type *) 0;
}

/* See symtab.h.  */

bool
iterate_over_symbols (const struct block *block,
		      const lookup_name_info &name,
		      const domain_search_flags domain,
		      gdb::function_view<symbol_found_callback_ftype> callback)
{
  for (struct symbol *sym : block_iterator_range (block, &name))
    {
      if (sym->matches (domain))
	{
	  struct block_symbol block_sym = {sym, block};

	  if (!callback (&block_sym))
	    return false;
	}
    }
  return true;
}

/* See symtab.h.  */

bool
iterate_over_symbols_terminated
  (const struct block *block,
   const lookup_name_info &name,
   const domain_search_flags domain,
   gdb::function_view<symbol_found_callback_ftype> callback)
{
  if (!iterate_over_symbols (block, name, domain, callback))
    return false;
  struct block_symbol block_sym = {nullptr, block};
  return callback (&block_sym);
}

/* Find the compunit symtab associated with PC and SECTION.
   This will read in debug info as necessary.  */

struct compunit_symtab *
find_pc_sect_compunit_symtab (CORE_ADDR pc, struct obj_section *section)
{
  struct compunit_symtab *best_cust = NULL;
  CORE_ADDR best_cust_range = 0;

  /* If we know that this is not a text address, return failure.  This is
     necessary because we loop based on the block's high and low code
     addresses, which do not include the data ranges, and because
     we call find_pc_sect_psymtab which has a similar restriction based
     on the partial_symtab's texthigh and textlow.  */
  bound_minimal_symbol msymbol
    = lookup_minimal_symbol_by_pc_section (pc, section);
  if (msymbol.minsym && msymbol.minsym->data_p ())
    return NULL;

  /* Search all symtabs for the one whose file contains our address, and which
     is the smallest of all the ones containing the address.  This is designed
     to deal with a case like symtab a is at 0x1000-0x2000 and 0x3000-0x4000
     and symtab b is at 0x2000-0x3000.  So the GLOBAL_BLOCK for a is from
     0x1000-0x4000, but for address 0x2345 we want to return symtab b.

     This happens for native ecoff format, where code from included files
     gets its own symtab.  The symtab for the included file should have
     been read in already via the dependency mechanism.
     It might be swifter to create several symtabs with the same name
     like xcoff does (I'm not sure).

     It also happens for objfiles that have their functions reordered.
     For these, the symtab we are looking for is not necessarily read in.  */

  for (objfile *obj_file : current_program_space->objfiles ())
    {
      for (compunit_symtab *cust : obj_file->compunits ())
	{
	  const struct blockvector *bv = cust->blockvector ();
	  const struct block *global_block = bv->global_block ();
	  CORE_ADDR start = global_block->start ();
	  CORE_ADDR end = global_block->end ();
	  bool in_range_p = start <= pc && pc < end;
	  if (!in_range_p)
	    continue;

	  if (bv->map () != nullptr)
	    {
	      if (bv->map ()->find (pc) == nullptr)
		continue;

	      return cust;
	    }

	  CORE_ADDR range = end - start;
	  if (best_cust != nullptr
	      && range >= best_cust_range)
	    /* Cust doesn't have a smaller range than best_cust, skip it.  */
	    continue;
	
	  /* For an objfile that has its functions reordered,
	     find_pc_psymtab will find the proper partial symbol table
	     and we simply return its corresponding symtab.  */
	  /* In order to better support objfiles that contain both
	     stabs and coff debugging info, we continue on if a psymtab
	     can't be found.  */
	  struct compunit_symtab *result
	    = obj_file->find_pc_sect_compunit_symtab (msymbol, pc,
						      section, 0);
	  if (result != nullptr)
	    return result;

	  if (section != 0)
	    {
	      struct symbol *found_sym = nullptr;

	      for (int b_index = GLOBAL_BLOCK;
		   b_index <= STATIC_BLOCK && found_sym == nullptr;
		   ++b_index)
		{
		  const struct block *b = bv->block (b_index);
		  for (struct symbol *sym : block_iterator_range (b))
		    {
		      if (matching_obj_sections (sym->obj_section (obj_file),
						 section))
			{
			  found_sym = sym;
			  break;
			}
		    }
		}
	      if (found_sym == nullptr)
		continue;		/* No symbol in this symtab matches
					   section.  */
	    }

	  /* Cust is best found sofar, save it.  */
	  best_cust = cust;
	  best_cust_range = range;
	}
    }

  if (best_cust != NULL)
    return best_cust;

  /* Not found in symtabs, search the "quick" symtabs (e.g. psymtabs).  */

  for (objfile *objf : current_program_space->objfiles ())
    {
      struct compunit_symtab *result
	= objf->find_pc_sect_compunit_symtab (msymbol, pc, section, 1);
      if (result != NULL)
	return result;
    }

  return NULL;
}

/* Find the compunit symtab associated with PC.
   This will read in debug info as necessary.
   Backward compatibility, no section.  */

struct compunit_symtab *
find_pc_compunit_symtab (CORE_ADDR pc)
{
  return find_pc_sect_compunit_symtab (pc, find_pc_mapped_section (pc));
}

/* See symtab.h.  */

struct symbol *
find_symbol_at_address (CORE_ADDR address)
{
  /* A helper function to search a given symtab for a symbol matching
     ADDR.  */
  auto search_symtab = [] (compunit_symtab *symtab, CORE_ADDR addr) -> symbol *
    {
      const struct blockvector *bv = symtab->blockvector ();

      for (int i = GLOBAL_BLOCK; i <= STATIC_BLOCK; ++i)
	{
	  const struct block *b = bv->block (i);

	  for (struct symbol *sym : block_iterator_range (b))
	    {
	      if (sym->aclass () == LOC_STATIC
		  && sym->value_address () == addr)
		return sym;
	    }
	}
      return nullptr;
    };

  for (objfile *objfile : current_program_space->objfiles ())
    {
      /* If this objfile was read with -readnow, then we need to
	 search the symtabs directly.  */
      if ((objfile->flags & OBJF_READNOW) != 0)
	{
	  for (compunit_symtab *symtab : objfile->compunits ())
	    {
	      struct symbol *sym = search_symtab (symtab, address);
	      if (sym != nullptr)
		return sym;
	    }
	}
      else
	{
	  struct compunit_symtab *symtab
	    = objfile->find_compunit_symtab_by_address (address);
	  if (symtab != NULL)
	    {
	      struct symbol *sym = search_symtab (symtab, address);
	      if (sym != nullptr)
		return sym;
	    }
	}
    }

  return NULL;
}



/* Find the source file and line number for a given PC value and SECTION.
   Return a structure containing a symtab pointer, a line number,
   and a pc range for the entire source line.
   The value's .pc field is NOT the specified pc.
   NOTCURRENT nonzero means, if specified pc is on a line boundary,
   use the line that ends there.  Otherwise, in that case, the line
   that begins there is used.  */

/* The big complication here is that a line may start in one file, and end just
   before the start of another file.  This usually occurs when you #include
   code in the middle of a subroutine.  To properly find the end of a line's PC
   range, we must search all symtabs associated with this compilation unit, and
   find the one whose first PC is closer than that of the next line in this
   symtab.  */

struct symtab_and_line
find_pc_sect_line (CORE_ADDR pc, struct obj_section *section, int notcurrent)
{
  struct compunit_symtab *cust;
  const linetable *l;
  int len;
  const linetable_entry *item;
  const struct blockvector *bv;

  /* Info on best line seen so far, and where it starts, and its file.  */

  const linetable_entry *best = NULL;
  CORE_ADDR best_end = 0;
  struct symtab *best_symtab = 0;

  /* Store here the first line number
     of a file which contains the line at the smallest pc after PC.
     If we don't find a line whose range contains PC,
     we will use a line one less than this,
     with a range from the start of that file to the first line's pc.  */
  const linetable_entry *alt = NULL;

  /* Info on best line seen in this file.  */

  const linetable_entry *prev;

  /* If this pc is not from the current frame,
     it is the address of the end of a call instruction.
     Quite likely that is the start of the following statement.
     But what we want is the statement containing the instruction.
     Fudge the pc to make sure we get that.  */

  /* It's tempting to assume that, if we can't find debugging info for
     any function enclosing PC, that we shouldn't search for line
     number info, either.  However, GAS can emit line number info for
     assembly files --- very helpful when debugging hand-written
     assembly code.  In such a case, we'd have no debug info for the
     function, but we would have line info.  */

  if (notcurrent)
    pc -= 1;

  /* elz: added this because this function returned the wrong
     information if the pc belongs to a stub (import/export)
     to call a shlib function.  This stub would be anywhere between
     two functions in the target, and the line info was erroneously
     taken to be the one of the line before the pc.  */

  /* RT: Further explanation:

   * We have stubs (trampolines) inserted between procedures.
   *
   * Example: "shr1" exists in a shared library, and a "shr1" stub also
   * exists in the main image.
   *
   * In the minimal symbol table, we have a bunch of symbols
   * sorted by start address.  The stubs are marked as "trampoline",
   * the others appear as text. E.g.:
   *
   *  Minimal symbol table for main image
   *     main:  code for main (text symbol)
   *     shr1: stub  (trampoline symbol)
   *     foo:   code for foo (text symbol)
   *     ...
   *  Minimal symbol table for "shr1" image:
   *     ...
   *     shr1: code for shr1 (text symbol)
   *     ...
   *
   * So the code below is trying to detect if we are in the stub
   * ("shr1" stub), and if so, find the real code ("shr1" trampoline),
   * and if found,  do the symbolization from the real-code address
   * rather than the stub address.
   *
   * Assumptions being made about the minimal symbol table:
   *   1. lookup_minimal_symbol_by_pc() will return a trampoline only
   *      if we're really in the trampoline.s If we're beyond it (say
   *      we're in "foo" in the above example), it'll have a closer
   *      symbol (the "foo" text symbol for example) and will not
   *      return the trampoline.
   *   2. lookup_minimal_symbol_text() will find a real text symbol
   *      corresponding to the trampoline, and whose address will
   *      be different than the trampoline address.  I put in a sanity
   *      check for the address being the same, to avoid an
   *      infinite recursion.
   */
  bound_minimal_symbol msymbol = lookup_minimal_symbol_by_pc (pc);
  if (msymbol.minsym != NULL)
    if (msymbol.minsym->type () == mst_solib_trampoline)
      {
	bound_minimal_symbol mfunsym
	  = lookup_minimal_symbol_text (current_program_space,
					msymbol.minsym->linkage_name (),
					nullptr);

	if (mfunsym.minsym == NULL)
	  /* I eliminated this warning since it is coming out
	   * in the following situation:
	   * gdb shmain // test program with shared libraries
	   * (gdb) break shr1  // function in shared lib
	   * Warning: In stub for ...
	   * In the above situation, the shared lib is not loaded yet,
	   * so of course we can't find the real func/line info,
	   * but the "break" still works, and the warning is annoying.
	   * So I commented out the warning.  RT */
	  /* warning ("In stub for %s; unable to find real function/line info",
	     msymbol->linkage_name ()); */
	  ;
	/* fall through */
	else if (mfunsym.value_address ()
		 == msymbol.value_address ())
	  /* Avoid infinite recursion */
	  /* See above comment about why warning is commented out.  */
	  /* warning ("In stub for %s; unable to find real function/line info",
	     msymbol->linkage_name ()); */
	  ;
	/* fall through */
	else
	  {
	    /* Detect an obvious case of infinite recursion.  If this
	       should occur, we'd like to know about it, so error out,
	       fatally.  */
	    if (mfunsym.value_address () == pc)
	      internal_error (_("Infinite recursion detected in find_pc_sect_line;"
		  "please file a bug report"));

	    return find_pc_line (mfunsym.value_address (), 0);
	  }
      }

  symtab_and_line val;
  val.pspace = current_program_space;

  cust = find_pc_sect_compunit_symtab (pc, section);
  if (cust == NULL)
    {
      /* If no symbol information, return previous pc.  */
      if (notcurrent)
	pc++;
      val.pc = pc;
      return val;
    }

  bv = cust->blockvector ();
  struct objfile *objfile = cust->objfile ();

  /* Look at all the symtabs that share this blockvector.
     They all have the same apriori range, that we found was right;
     but they have different line tables.  */

  for (symtab *iter_s : cust->filetabs ())
    {
      /* Find the best line in this symtab.  */
      l = iter_s->linetable ();
      if (!l)
	continue;
      len = l->nitems;
      if (len <= 0)
	{
	  /* I think len can be zero if the symtab lacks line numbers
	     (e.g. gcc -g1).  (Either that or the LINETABLE is NULL;
	     I'm not sure which, and maybe it depends on the symbol
	     reader).  */
	  continue;
	}

      prev = NULL;
      item = l->item;		/* Get first line info.  */

      /* Is this file's first line closer than the first lines of other files?
	 If so, record this file, and its first line, as best alternate.  */
      if (item->pc (objfile) > pc
	  && (!alt || item->unrelocated_pc () < alt->unrelocated_pc ()))
	alt = item;

      auto pc_compare = [] (const unrelocated_addr &comp_pc,
			    const struct linetable_entry & lhs)
      {
	return comp_pc < lhs.unrelocated_pc ();
      };

      const linetable_entry *first = item;
      const linetable_entry *last = item + len;
      item = (std::upper_bound
	      (first, last,
	       unrelocated_addr (pc - objfile->text_section_offset ()),
	       pc_compare));
      if (item != first)
	{