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,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include "defs.h"
  22 #include "symtab.h"
  23 #include "gdbtypes.h"
  24 #include "expression.h"
  25 #include "parser-defs.h"
  26 #include "language.h"
  27 #include "value.h"
  28 #include "c-lang.h"
  29 #include "scm-lang.h"
  30 #include "scm-tags.h"
  31 #include "gdb_string.h"
  32 #include "gdbcore.h"
  33
  34 extern void _initialize_scheme_language PARAMS ((void));
  35 static value_ptr evaluate_subexp_scm PARAMS ((struct type *, struct expression *,
  36                                               int *, enum noside));
  37 static value_ptr scm_lookup_name PARAMS ((char *));
  38 static int in_eval_c PARAMS ((void));
  39 static void scm_printstr PARAMS ((GDB_FILE * stream, char *string, unsigned int length, int width, int force_ellipses));
  40
  41 extern struct type **CONST_PTR (c_builtin_types[]);
  42
  43 struct type *builtin_type_scm;
  44
  45 void
  46 scm_printchar (c, stream)
  47      int c;
  48      GDB_FILE *stream;
  49 {
  50   fprintf_filtered (stream, "#\\%c", c);
  51 }
  52
  53 static void
  54 scm_printstr (stream, string, length, width, force_ellipses)
  55      GDB_FILE *stream;
  56      char *string;
  57      unsigned int length;
  58      int width;
  59      int force_ellipses;
  60 {
  61   fprintf_filtered (stream, "\"%s\"", string);
  62 }
  63
  64 int
  65 is_scmvalue_type (type)
  66      struct type *type;
  67 {
  68   if (TYPE_CODE (type) == TYPE_CODE_INT
  69       && TYPE_NAME (type) && strcmp (TYPE_NAME (type), "SCM") == 0)
  70     {
  71       return 1;
  72     }
  73   return 0;
  74 }
  75
  76 /* Get the INDEX'th SCM value, assuming SVALUE is the address
  77    of the 0'th one.  */
  78
  79 LONGEST
  80 scm_get_field (svalue, index)
  81      LONGEST svalue;
  82      int index;
  83 {
  84   char buffer[20];
  85   read_memory (SCM2PTR (svalue) + index * TYPE_LENGTH (builtin_type_scm),
  86                buffer, TYPE_LENGTH (builtin_type_scm));
  87   return extract_signed_integer (buffer, TYPE_LENGTH (builtin_type_scm));
  88 }
  89
  90 /* Unpack a value of type TYPE in buffer VALADDR as an integer
  91    (if CONTEXT == TYPE_CODE_IN), a pointer (CONTEXT == TYPE_CODE_PTR),
  92    or Boolean (CONTEXT == TYPE_CODE_BOOL).  */
  93
  94 LONGEST
  95 scm_unpack (type, valaddr, context)
  96      struct type *type;
  97      char *valaddr;
  98      enum type_code context;
  99 {
 100   if (is_scmvalue_type (type))
 101     {
 102       LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));
 103       if (context == TYPE_CODE_BOOL)
 104         {
 105           if (svalue == SCM_BOOL_F)
 106             return 0;
 107           else
 108             return 1;
 109         }
 110       switch (7 & (int) svalue)
 111         {
 112         case 2:
 113         case 6:         /* fixnum */
 114           return svalue >> 2;
 115         case 4:         /* other immediate value */
 116           if (SCM_ICHRP (svalue))       /* character */
 117             return SCM_ICHR (svalue);
 118           else if (SCM_IFLAGP (svalue))
 119             {
 120               switch ((int) svalue)
 121                 {
 122 #ifndef SICP
 123                 case SCM_EOL:
 124 #endif
 125                 case SCM_BOOL_F:
 126                   return 0;
 127                 case SCM_BOOL_T:
 128                   return 1;
 129                 }
 130             }
 131           error ("Value can't be converted to integer.");
 132         default:
 133           return svalue;
 134         }
 135     }
 136   else
 137     return unpack_long (type, valaddr);
 138 }
 139
 140 /* True if we're correctly in Guile's eval.c (the evaluator and apply). */
 141
 142 static int
 143 in_eval_c ()
 144 {
 145   if (current_source_symtab && current_source_symtab->filename)
 146     {
 147       char *filename = current_source_symtab->filename;
 148       int len = strlen (filename);
 149       if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)
 150         return 1;
 151     }
 152   return 0;
 153 }
 154
 155 /* Lookup a value for the variable named STR.
 156    First lookup in Scheme context (using the scm_lookup_cstr inferior
 157    function), then try lookup_symbol for compiled variables. */
 158
 159 static value_ptr
 160 scm_lookup_name (str)
 161      char *str;
 162 {
 163   value_ptr args[3];
 164   int len = strlen (str);
 165   value_ptr func, val;
 166   struct symbol *sym;
 167   args[0] = value_allocate_space_in_inferior (len);
 168   args[1] = value_from_longest (builtin_type_int, len);
 169   write_memory (value_as_long (args[0]), str, len);
 170
 171   if (in_eval_c ()
 172       && (sym = lookup_symbol ("env",
 173                                expression_context_block,
 174                                VAR_NAMESPACE, (int *) NULL,
 175                                (struct symtab **) NULL)) != NULL)
 176     args[2] = value_of_variable (sym, expression_context_block);
 177   else
 178     /* FIXME in this case, we should try lookup_symbol first */
 179     args[2] = value_from_longest (builtin_type_scm, SCM_EOL);
 180
 181   func = find_function_in_inferior ("scm_lookup_cstr");
 182   val = call_function_by_hand (func, 3, args);
 183   if (!value_logical_not (val))
 184     return value_ind (val);
 185
 186   sym = lookup_symbol (str,
 187                        expression_context_block,
 188                        VAR_NAMESPACE, (int *) NULL,
 189                        (struct symtab **) NULL);
 190   if (sym)
 191     return value_of_variable (sym, NULL);
 192   error ("No symbol \"%s\" in current context.");
 193 }
 194
 195 value_ptr
 196 scm_evaluate_string (str, len)
 197      char *str;
 198      int len;
 199 {
 200   value_ptr func;
 201   value_ptr addr = value_allocate_space_in_inferior (len + 1);
 202   LONGEST iaddr = value_as_long (addr);
 203   write_memory (iaddr, str, len);
 204   /* FIXME - should find and pass env */
 205   write_memory (iaddr + len, "", 1);
 206   func = find_function_in_inferior ("scm_evstr");
 207   return call_function_by_hand (func, 1, &addr);
 208 }
 209
 210 static value_ptr
 211 evaluate_subexp_scm (expect_type, exp, pos, noside)
 212      struct type *expect_type;
 213      register struct expression *exp;
 214      register int *pos;
 215      enum noside noside;
 216 {
 217   enum exp_opcode op = exp->elts[*pos].opcode;
 218   int len, pc;
 219   char *str;
 220   switch (op)
 221     {
 222     case OP_NAME:
 223       pc = (*pos)++;
 224       len = longest_to_int (exp->elts[pc + 1].longconst);
 225       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 226       if (noside == EVAL_SKIP)
 227         goto nosideret;
 228       str = &exp->elts[pc + 2].string;
 229       return scm_lookup_name (str);
 230     case OP_EXPRSTRING:
 231       pc = (*pos)++;
 232       len = longest_to_int (exp->elts[pc + 1].longconst);
 233       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 234       if (noside == EVAL_SKIP)
 235         goto nosideret;
 236       str = &exp->elts[pc + 2].string;
 237       return scm_evaluate_string (str, len);
 238     default:;
 239     }
 240   return evaluate_subexp_standard (expect_type, exp, pos, noside);
 241 nosideret:
 242   return value_from_longest (builtin_type_long, (LONGEST) 1);
 243 }
 244
 245 const struct language_defn scm_language_defn =
 246 {
 247   "scheme",                     /* Language name */
 248   language_scm,
 249   c_builtin_types,
 250   range_check_off,
 251   type_check_off,
 252   scm_parse,
 253   c_error,
 254   evaluate_subexp_scm,
 255   scm_printchar,                /* Print a character constant */
 256   scm_printstr,                 /* Function to print string constant */
 257   NULL,                         /* Function to print a single character */
 258   NULL,                         /* Create fundamental type in this language */
 259   c_print_type,                 /* Print a type using appropriate syntax */
 260   scm_val_print,                /* Print a value using appropriate syntax */
 261   scm_value_print,              /* Print a top-level value */
 262   {"", "", "", ""},             /* Binary format info */
 263   {"#o%lo", "#o", "o", ""},     /* Octal format info */
 264   {"%ld", "", "d", ""},         /* Decimal format info */
 265   {"#x%lX", "#X", "X", ""},     /* Hex format info */
 266   NULL,                         /* expression operators for printing */
 267   1,                            /* c-style arrays */
 268   0,                            /* String lower bound */
 269   &builtin_type_char,           /* Type of string elements */
 270   LANG_MAGIC
 271 };
 272
 273 void
 274 _initialize_scheme_language ()
 275 {
 276   add_language (&scm_language_defn);
 277   builtin_type_scm = init_type (TYPE_CODE_INT,
 278                                 TARGET_LONG_BIT / TARGET_CHAR_BIT,
 279                                 0, "SCM", (struct objfile *) NULL);
 280 }