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