guile/libguile/debug.c

/* Debugging extensions for Guile

   Copyright 1995-2003,2006,2008-2013,2018,2025
     Free Software Foundation, Inc.

   This file is part of Guile.

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

   Guile 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 Lesser General Public
   License for more details.

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


#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <errno.h>

#ifdef HAVE_GETRLIMIT
#include <sys/time.h>
#include <sys/resource.h>
#endif

#ifdef __MINGW32__
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
#endif

#include "alist.h"
#include "async.h"
#include "continuations.h"
#include "dynwind.h"
#include "eval.h"
#include "feature.h"
#include "fluids.h"
#include "gsubr.h"
#include "list.h"
#include "macros.h"
#include "memoize.h"
#include "modules.h"
#include "pairs.h"
#include "ports.h"
#include "private-options.h"
#include "procprop.h"
#include "programs.h"
#include "read.h"
#include "smob.h"
#include "stackchk.h"
#include "strports.h"
#include "struct.h"
#include "throw.h"
#include "variable.h"
#include "vm.h"

#include "debug.h"




/*
 * Debugging options.
 */

scm_t_option scm_debug_opts[] = {
  { SCM_OPTION_BOOLEAN, "backwards", 0,
    "Display backtrace in anti-chronological order." },
  { SCM_OPTION_INTEGER, "width", 79, "Maximal width of backtrace." },
  { SCM_OPTION_INTEGER, "depth", 20, "Maximal length of printed backtrace." },
  { SCM_OPTION_BOOLEAN, "backtrace", 1, "Show backtrace on error." },
  /* This default stack limit will be overridden by init_stack_limit(),
     if we have getrlimit() and the stack limit is not INFINITY. But it is still
     important, as some systems have both the soft and the hard limits set to
     INFINITY; in that case we fall back to this value.

     The situation is aggravated by certain compilers, which can consume
     "beaucoup de stack", as they say in France.

     See http://thread.gmane.org/gmane.lisp.guile.devel/8599/focus=8662 for
     more discussion. This setting is 640 KB on 32-bit arches (should be enough
     for anyone!) or a whoppin' 1280 KB on 64-bit arches.
  */
  { SCM_OPTION_INTEGER, "stack", 160000, "Stack size limit (measured in words; 0 = no check)." },
  { SCM_OPTION_SCM, "show-file-name", SCM_BOOL_T_BITS,
    "Show file names and line numbers "
    "in backtraces when not `#f'.  A value of `base' "
    "displays only base names, while `#t' displays full names."},
  { SCM_OPTION_BOOLEAN, "warn-deprecated", 0,
    "Warn when deprecated features are used." },
  { 0 }, 
};


/* {Run time control of the debugging evaluator}
 */

SCM_DEFINE (scm_debug_options, "debug-options-interface", 0, 1, 0, 
            (SCM setting),
	    "Option interface for the debug options. Instead of using\n"
	    "this procedure directly, use the procedures @code{debug-enable},\n"
	    "@code{debug-disable}, @code{debug-set!} and @code{debug-options}.")
#define FUNC_NAME s_scm_debug_options
{
  SCM ans;

  ans = scm_options (setting, scm_debug_opts, FUNC_NAME);
  scm_stack_checking_enabled_p = SCM_STACK_CHECKING_P;

  return ans;
}
#undef FUNC_NAME




#if 0
SCM_REGISTER_PROC (s_reverse_lookup, "reverse-lookup", 2, 0, 0, scm_reverse_lookup);
#endif

SCM
scm_reverse_lookup (SCM env, SCM data)
{
  while (scm_is_pair (env) && scm_is_pair (SCM_CAR (env)))
    {
      SCM names = SCM_CAAR (env);
      SCM values = SCM_CDAR (env);
      while (scm_is_pair (names))
	{
	  if (scm_is_eq (SCM_CAR (values), data))
	    return SCM_CAR (names);
	  names = SCM_CDR (names);
	  values = SCM_CDR (values);
	}
      if (!scm_is_null (names) && scm_is_eq (values, data))
	return names;
      env = SCM_CDR (env);
    }
  return SCM_BOOL_F;
}



/* Undocumented debugging procedure */
#ifdef GUILE_DEBUG
SCM_DEFINE (scm_debug_hang, "debug-hang", 0, 1, 0, 
            (SCM obj),
	    "Go into an endless loop, which can be only terminated with\n"
	    "a debugger.")
#define FUNC_NAME s_scm_debug_hang
{
  int go = 0;
  while (!go) ;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
#endif

static SCM local_eval_var;

static void
init_local_eval_var (void)
{
  local_eval_var = scm_c_public_variable ("ice-9 local-eval", "local-eval");
}

SCM
scm_local_eval (SCM exp, SCM env)
{
  static scm_i_pthread_once_t once = SCM_I_PTHREAD_ONCE_INIT;
  scm_i_pthread_once (&once, init_local_eval_var);

  return scm_call_2 (scm_variable_ref (local_eval_var), exp, env);
}

static void
init_stack_limit (void)
{
#if defined HAVE_GETRLIMIT
  struct rlimit lim;
  if (getrlimit (RLIMIT_STACK, &lim) == 0)
      {
        rlim_t bytes = lim.rlim_cur;

        /* set our internal stack limit to 80% of the rlimit. */
        if (bytes == RLIM_INFINITY)
          bytes = lim.rlim_max;

        if (bytes != RLIM_INFINITY)
          SCM_STACK_LIMIT = bytes * 8 / 10 / sizeof (scm_t_bits);
      }
  errno = 0;
#elif defined __MINGW32__
  MEMORY_BASIC_INFORMATION m;
  uintptr_t bytes;

  if (VirtualQuery ((LPCVOID) &m, &m, sizeof m))
    {
      bytes = (DWORD_PTR) m.BaseAddress + m.RegionSize
	       - (DWORD_PTR) m.AllocationBase;
      SCM_STACK_LIMIT = bytes * 8 / 10 / sizeof (scm_t_bits);
    }
#endif
}



void
scm_init_debug ()
{
  init_stack_limit ();
  scm_init_opts (scm_debug_options, scm_debug_opts);

  scm_add_feature ("debug-extensions");

#include "debug.x"
}