gdb/scm-lang.c

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