gdb/scm-lang.c

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