scm-lang.c   [plain text]

/* Scheme/Guile language support routines for GDB, the GNU debugger.
   Copyright 1995, 2000 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 2 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, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include "defs.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "expression.h"
#include "parser-defs.h"
#include "language.h"
#include "value.h"
#include "c-lang.h"
#include "scm-lang.h"
#include "scm-tags.h"
#include "gdb_string.h"
#include "gdbcore.h"

extern void _initialize_scheme_language (void);
static value_ptr evaluate_subexp_scm (struct type *, struct expression *,
				      int *, enum noside);
static value_ptr scm_lookup_name (char *);
static int in_eval_c (void);
static void scm_printstr (struct ui_file * stream, char *string,
			  unsigned int length, int width,
			  int force_ellipses);

extern struct type **CONST_PTR (c_builtin_types[]);

struct type *builtin_type_scm;

void
scm_printchar (int c, struct ui_file *stream)
{
  fprintf_filtered (stream, "#\\%c", c);
}

static void
scm_printstr (struct ui_file *stream, char *string, unsigned int length,
	      int width, int force_ellipses)
{
  fprintf_filtered (stream, "\"%s\"", string);
}

int
is_scmvalue_type (struct type *type)
{
  if (TYPE_CODE (type) == TYPE_CODE_INT
      && TYPE_NAME (type) && strcmp (TYPE_NAME (type), "SCM") == 0)
    {
      return 1;
    }
  return 0;
}

/* Get the INDEX'th SCM value, assuming SVALUE is the address
   of the 0'th one.  */

LONGEST
scm_get_field (LONGEST svalue, int index)
{
  char buffer[20];
  read_memory (SCM2PTR (svalue) + index * TYPE_LENGTH (builtin_type_scm),
	       buffer, TYPE_LENGTH (builtin_type_scm));
  return extract_signed_integer (buffer, TYPE_LENGTH (builtin_type_scm));
}

/* Unpack a value of type TYPE in buffer VALADDR as an integer
   (if CONTEXT == TYPE_CODE_IN), a pointer (CONTEXT == TYPE_CODE_PTR),
   or Boolean (CONTEXT == TYPE_CODE_BOOL).  */

LONGEST
scm_unpack (struct type *type, char *valaddr, enum type_code context)
{
  if (is_scmvalue_type (type))
    {
      LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));
      if (context == TYPE_CODE_BOOL)
	{
	  if (svalue == SCM_BOOL_F)
	    return 0;
	  else
	    return 1;
	}
      switch (7 & (int) svalue)
	{
	case 2:
	case 6:		/* fixnum */
	  return svalue >> 2;
	case 4:		/* other immediate value */
	  if (SCM_ICHRP (svalue))	/* character */
	    return SCM_ICHR (svalue);
	  else if (SCM_IFLAGP (svalue))
	    {
	      switch ((int) svalue)
		{
#ifndef SICP
		case SCM_EOL:
#endif
		case SCM_BOOL_F:
		  return 0;
		case SCM_BOOL_T:
		  return 1;
		}
	    }
	  error ("Value can't be converted to integer.");
	default:
	  return svalue;
	}
    }
  else
    return unpack_long (type, valaddr);
}

/* True if we're correctly in Guile's eval.c (the evaluator and apply). */

static int
in_eval_c (void)
{
  if (current_source_symtab && current_source_symtab->filename)
    {
      char *filename = current_source_symtab->filename;
      int len = strlen (filename);
      if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)
	return 1;
    }
  return 0;
}

/* Lookup a value for the variable named STR.
   First lookup in Scheme context (using the scm_lookup_cstr inferior
   function), then try lookup_symbol for compiled variables. */

static value_ptr
scm_lookup_name (char *str)
{
  value_ptr args[3];
  int len = strlen (str);
  value_ptr func, val;
  struct symbol *sym;
  args[0] = value_allocate_space_in_inferior (len);
  args[1] = value_from_longest (builtin_type_int, len);
  write_memory (value_as_long (args[0]), str, len);

  if (in_eval_c ()
      && (sym = lookup_symbol ("env",
			       expression_context_block,
			       VAR_NAMESPACE, (int *) NULL,
			       (struct symtab **) NULL)) != NULL)
    args[2] = value_of_variable (sym, expression_context_block);
  else
    /* FIXME in this case, we should try lookup_symbol first */
    args[2] = value_from_longest (builtin_type_scm, SCM_EOL);

  func = find_function_in_inferior ("scm_lookup_cstr", builtin_type_voidptrfuncptr);
  val = call_function_by_hand (func, 3, args);
  if (!value_logical_not (val))
    return value_ind (val);

  sym = lookup_symbol (str,
		       expression_context_block,
		       VAR_NAMESPACE, (int *) NULL,
		       (struct symtab **) NULL);
  if (sym)
    return value_of_variable (sym, NULL);
  error ("No symbol \"%s\" in current context.");
}

value_ptr
scm_evaluate_string (char *str, int len)
{
  value_ptr func;
  value_ptr addr = value_allocate_space_in_inferior (len + 1);
  LONGEST iaddr = value_as_long (addr);
  write_memory (iaddr, str, len);
  /* FIXME - should find and pass env */
  write_memory (iaddr + len, "", 1);
  func = find_function_in_inferior ("scm_evstr", builtin_type_voidptrfuncptr);
  return call_function_by_hand (func, 1, &addr);
}

static value_ptr
evaluate_subexp_scm (struct type *expect_type, register struct expression *exp,
		     register int *pos, enum noside noside)
{
  enum exp_opcode op = exp->elts[*pos].opcode;
  int len, pc;
  char *str;
  switch (op)
    {
    case OP_NAME:
      pc = (*pos)++;
      len = longest_to_int (exp->elts[pc + 1].longconst);
      (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
      if (noside == EVAL_SKIP)
	goto nosideret;
      str = &exp->elts[pc + 2].string;
      return scm_lookup_name (str);
    case OP_EXPRSTRING:
      pc = (*pos)++;
      len = longest_to_int (exp->elts[pc + 1].longconst);
      (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
      if (noside == EVAL_SKIP)
	goto nosideret;
      str = &exp->elts[pc + 2].string;
      return scm_evaluate_string (str, len);
    default:;
    }
  return evaluate_subexp_standard (expect_type, exp, pos, noside);
nosideret:
  return value_from_longest (builtin_type_long, (LONGEST) 1);
}

const struct language_defn scm_language_defn =
{
  "scheme",			/* Language name */
  language_scm,
  c_builtin_types,
  range_check_off,
  type_check_off,
  case_sensitive_off,
  scm_parse,
  c_error,
  evaluate_subexp_scm,
  scm_printchar,		/* Print a character constant */
  scm_printstr,			/* Function to print string constant */
  NULL,				/* Function to print a single character */
  NULL,				/* Create fundamental type in this language */
  c_print_type,			/* Print a type using appropriate syntax */
  scm_val_print,		/* Print a value using appropriate syntax */
  scm_value_print,		/* Print a top-level value */
  {"", "", "", ""},		/* Binary format info */
  {"#o%lo", "#o", "o", ""},	/* Octal format info */
  {"%ld", "", "d", ""},		/* Decimal format info */
  {"#x%lX", "#X", "X", ""},	/* Hex format info */
  NULL,				/* expression operators for printing */
  1,				/* c-style arrays */
  0,				/* String lower bound */
  &builtin_type_char,		/* Type of string elements */
  LANG_MAGIC
};

void
_initialize_scheme_language (void)
{
  add_language (&scm_language_defn);
  builtin_type_scm = init_type (TYPE_CODE_INT,
				TARGET_LONG_BIT / TARGET_CHAR_BIT,
				0, "SCM", (struct objfile *) NULL);
}