1/* Scheme/Guile language support routines for GDB, the GNU debugger.
2
3   Copyright 1995, 1996, 1998, 2000, 2001, 2002, 2003, 2004 Free Software
4   Foundation, Inc.
5
6   This file is part of GDB.
7
8   This program is free software; you can redistribute it and/or modify
9   it under the terms of the GNU General Public License as published by
10   the Free Software Foundation; either version 2 of the License, or
11   (at your option) any later version.
12
13   This program is distributed in the hope that it will be useful,
14   but WITHOUT ANY WARRANTY; without even the implied warranty of
15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16   GNU General Public License for more details.
17
18   You should have received a copy of the GNU General Public License
19   along with this program; if not, write to the Free Software
20   Foundation, Inc., 59 Temple Place - Suite 330,
21   Boston, MA 02111-1307, USA.  */
22
23#include "defs.h"
24#include "symtab.h"
25#include "gdbtypes.h"
26#include "expression.h"
27#include "parser-defs.h"
28#include "language.h"
29#include "value.h"
30#include "c-lang.h"
31#include "scm-lang.h"
32#include "scm-tags.h"
33#include "source.h"
34#include "gdb_string.h"
35#include "gdbcore.h"
36#include "infcall.h"
37
38extern void _initialize_scheme_language (void);
39static struct value *evaluate_subexp_scm (struct type *, struct expression *,
40				      int *, enum noside);
41static struct value *scm_lookup_name (char *);
42static int in_eval_c (void);
43static void scm_printstr (struct ui_file * stream, char *string,
44			  unsigned int length, int width,
45			  int force_ellipses);
46
47struct type *builtin_type_scm;
48
49void
50scm_printchar (int c, struct ui_file *stream)
51{
52  fprintf_filtered (stream, "#\\%c", c);
53}
54
55static void
56scm_printstr (struct ui_file *stream, char *string, unsigned int length,
57	      int width, int force_ellipses)
58{
59  fprintf_filtered (stream, "\"%s\"", string);
60}
61
62int
63is_scmvalue_type (struct type *type)
64{
65  if (TYPE_CODE (type) == TYPE_CODE_INT
66      && TYPE_NAME (type) && strcmp (TYPE_NAME (type), "SCM") == 0)
67    {
68      return 1;
69    }
70  return 0;
71}
72
73/* Get the INDEX'th SCM value, assuming SVALUE is the address
74   of the 0'th one.  */
75
76LONGEST
77scm_get_field (LONGEST svalue, int index)
78{
79  char buffer[20];
80  read_memory (SCM2PTR (svalue) + index * TYPE_LENGTH (builtin_type_scm),
81	       buffer, TYPE_LENGTH (builtin_type_scm));
82  return extract_signed_integer (buffer, TYPE_LENGTH (builtin_type_scm));
83}
84
85/* Unpack a value of type TYPE in buffer VALADDR as an integer
86   (if CONTEXT == TYPE_CODE_IN), a pointer (CONTEXT == TYPE_CODE_PTR),
87   or Boolean (CONTEXT == TYPE_CODE_BOOL).  */
88
89LONGEST
90scm_unpack (struct type *type, const char *valaddr, enum type_code context)
91{
92  if (is_scmvalue_type (type))
93    {
94      LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));
95      if (context == TYPE_CODE_BOOL)
96	{
97	  if (svalue == SCM_BOOL_F)
98	    return 0;
99	  else
100	    return 1;
101	}
102      switch (7 & (int) svalue)
103	{
104	case 2:
105	case 6:		/* fixnum */
106	  return svalue >> 2;
107	case 4:		/* other immediate value */
108	  if (SCM_ICHRP (svalue))	/* character */
109	    return SCM_ICHR (svalue);
110	  else if (SCM_IFLAGP (svalue))
111	    {
112	      switch ((int) svalue)
113		{
114#ifndef SICP
115		case SCM_EOL:
116#endif
117		case SCM_BOOL_F:
118		  return 0;
119		case SCM_BOOL_T:
120		  return 1;
121		}
122	    }
123	  error ("Value can't be converted to integer.");
124	default:
125	  return svalue;
126	}
127    }
128  else
129    return unpack_long (type, valaddr);
130}
131
132/* True if we're correctly in Guile's eval.c (the evaluator and apply). */
133
134static int
135in_eval_c (void)
136{
137  struct symtab_and_line cursal = get_current_source_symtab_and_line ();
138
139  if (cursal.symtab && cursal.symtab->filename)
140    {
141      char *filename = cursal.symtab->filename;
142      int len = strlen (filename);
143      if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)
144	return 1;
145    }
146  return 0;
147}
148
149/* Lookup a value for the variable named STR.
150   First lookup in Scheme context (using the scm_lookup_cstr inferior
151   function), then try lookup_symbol for compiled variables. */
152
153static struct value *
154scm_lookup_name (char *str)
155{
156  struct value *args[3];
157  int len = strlen (str);
158  struct value *func;
159  struct value *val;
160  struct symbol *sym;
161  args[0] = value_allocate_space_in_inferior (len);
162  args[1] = value_from_longest (builtin_type_int, len);
163  write_memory (value_as_long (args[0]), str, len);
164
165  if (in_eval_c ()
166      && (sym = lookup_symbol ("env",
167			       expression_context_block,
168			       VAR_DOMAIN, (int *) NULL,
169			       (struct symtab **) NULL)) != NULL)
170    args[2] = value_of_variable (sym, expression_context_block);
171  else
172    /* FIXME in this case, we should try lookup_symbol first */
173    args[2] = value_from_longest (builtin_type_scm, SCM_EOL);
174
175  func = find_function_in_inferior ("scm_lookup_cstr");
176  val = call_function_by_hand (func, 3, args);
177  if (!value_logical_not (val))
178    return value_ind (val);
179
180  sym = lookup_symbol (str,
181		       expression_context_block,
182		       VAR_DOMAIN, (int *) NULL,
183		       (struct symtab **) NULL);
184  if (sym)
185    return value_of_variable (sym, NULL);
186  error ("No symbol \"%s\" in current context.", str);
187}
188
189struct value *
190scm_evaluate_string (char *str, int len)
191{
192  struct value *func;
193  struct value *addr = value_allocate_space_in_inferior (len + 1);
194  LONGEST iaddr = value_as_long (addr);
195  write_memory (iaddr, str, len);
196  /* FIXME - should find and pass env */
197  write_memory (iaddr + len, "", 1);
198  func = find_function_in_inferior ("scm_evstr");
199  return call_function_by_hand (func, 1, &addr);
200}
201
202static struct value *
203evaluate_subexp_scm (struct type *expect_type, struct expression *exp,
204		     int *pos, enum noside noside)
205{
206  enum exp_opcode op = exp->elts[*pos].opcode;
207  int len, pc;
208  char *str;
209  switch (op)
210    {
211    case OP_NAME:
212      pc = (*pos)++;
213      len = longest_to_int (exp->elts[pc + 1].longconst);
214      (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
215      if (noside == EVAL_SKIP)
216	goto nosideret;
217      str = &exp->elts[pc + 2].string;
218      return scm_lookup_name (str);
219    case OP_EXPRSTRING:
220      pc = (*pos)++;
221      len = longest_to_int (exp->elts[pc + 1].longconst);
222      (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
223      if (noside == EVAL_SKIP)
224	goto nosideret;
225      str = &exp->elts[pc + 2].string;
226      return scm_evaluate_string (str, len);
227    default:;
228    }
229  return evaluate_subexp_standard (expect_type, exp, pos, noside);
230nosideret:
231  return value_from_longest (builtin_type_long, (LONGEST) 1);
232}
233
234const struct exp_descriptor exp_descriptor_scm =
235{
236  print_subexp_standard,
237  operator_length_standard,
238  op_name_standard,
239  dump_subexp_body_standard,
240  evaluate_subexp_scm
241};
242
243const struct language_defn scm_language_defn =
244{
245  "scheme",			/* Language name */
246  language_scm,
247  NULL,
248  range_check_off,
249  type_check_off,
250  case_sensitive_off,
251  array_row_major,
252  &exp_descriptor_scm,
253  scm_parse,
254  c_error,
255  null_post_parser,
256  scm_printchar,		/* Print a character constant */
257  scm_printstr,			/* Function to print string constant */
258  NULL,				/* Function to print a single character */
259  NULL,				/* Create fundamental type in this language */
260  c_print_type,			/* Print a type using appropriate syntax */
261  scm_val_print,		/* Print a value using appropriate syntax */
262  scm_value_print,		/* Print a top-level value */
263  NULL,				/* Language specific skip_trampoline */
264  value_of_this,		/* value_of_this */
265  basic_lookup_symbol_nonlocal,	/* lookup_symbol_nonlocal */
266  basic_lookup_transparent_type,/* lookup_transparent_type */
267  NULL,				/* Language specific symbol demangler */
268  NULL,				/* Language specific class_name_from_physname */
269  NULL,				/* expression operators for printing */
270  1,				/* c-style arrays */
271  0,				/* String lower bound */
272  NULL,
273  default_word_break_characters,
274  c_language_arch_info,
275  LANG_MAGIC
276};
277
278void
279_initialize_scheme_language (void)
280{
281  add_language (&scm_language_defn);
282  builtin_type_scm = init_type (TYPE_CODE_INT,
283				TARGET_LONG_BIT / TARGET_CHAR_BIT,
284				0, "SCM", (struct objfile *) NULL);
285}
286