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
  32 extern struct type ** const (c_builtin_types[]);
  33 extern value_ptr value_allocate_space_in_inferior PARAMS ((int));
  34 extern value_ptr find_function_in_inferior PARAMS ((char*));
  35
  36 struct type *builtin_type_scm;
  37
  38 void
  39 scm_printchar (c, stream)
  40      int c;
  41      GDB_FILE *stream;
  42 {
  43   fprintf_filtered (stream, "#\\%c", c);
  44 }
  45
  46 static void
  47 scm_printstr (stream, string, length, force_ellipses)
  48      GDB_FILE *stream;
  49      char *string;
  50      unsigned int length;
  51      int force_ellipses;
  52 {
  53   fprintf_filtered (stream, "\"%s\"", string);
  54 }
  55
  56 int
  57 is_scmvalue_type (type)
  58      struct type *type;
  59 {
  60   if (TYPE_CODE (type) == TYPE_CODE_INT
  61       && TYPE_NAME (type) && strcmp (TYPE_NAME (type), "SCM") == 0)
  62     {
  63       return 1;
  64     }
  65   return 0;
  66 }
  67
  68 /* Get the INDEX'th SCM value, assuming SVALUE is the address
  69    of the 0'th one.  */
  70
  71 LONGEST
  72 scm_get_field (svalue, index)
  73      LONGEST svalue;
  74      int index;
  75 {
  76   value_ptr val;
  77   char buffer[20];
  78   read_memory (SCM2PTR (svalue) + index * TYPE_LENGTH (builtin_type_scm),
  79                buffer, TYPE_LENGTH (builtin_type_scm));
  80   return extract_signed_integer (buffer, TYPE_LENGTH (builtin_type_scm));
  81 }
  82
  83 /* Unpack a value of type TYPE in buffer VALADDR as an integer
  84    (if CONTEXT == TYPE_CODE_IN), a pointer (CONTEXT == TYPE_CODE_PTR),
  85    or Boolean (CONTEXT == TYPE_CODE_BOOL).  */
  86
  87 LONGEST
  88 scm_unpack (type, valaddr, context)
  89      struct type *type;
  90      char *valaddr;
  91      enum type_code context;
  92 {
  93   if (is_scmvalue_type (type))
  94     {
  95       LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));
  96       if (context == TYPE_CODE_BOOL)
  97         {
  98           if (svalue == SCM_BOOL_F)
  99             return 0;
 100           else
 101             return 1;
 102         }
 103       switch (7 & svalue)
 104         {
 105         case 2:  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 (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
 134 static int
 135 in_eval_c ()
 136 {
 137   if (current_source_symtab && current_source_symtab->filename)
 138     {
 139       char *filename = current_source_symtab->filename;
 140       int len = strlen (filename);
 141       if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)
 142         return 1;
 143     }
 144   return 0;
 145 }
 146
 147 /* Lookup a value for the variable named STR.
 148    First lookup in Scheme context (using the scm_lookup_cstr inferior
 149    function), then try lookup_symbol for compiled variables. */
 150
 151 value_ptr
 152 scm_lookup_name (str)
 153      char *str;
 154 {
 155   value_ptr args[3];
 156   int len = strlen (str);
 157   value_ptr symval, func, val;
 158   struct symbol *sym;
 159   args[0] = value_allocate_space_in_inferior (len);
 160   args[1] = value_from_longest (builtin_type_int, len);
 161   write_memory (value_as_long (args[0]), str, len);
 162
 163   if (in_eval_c ()
 164       && (sym = lookup_symbol ("env",
 165                                expression_context_block,
 166                                VAR_NAMESPACE, (int *) NULL,
 167                                (struct symtab **) NULL)) != NULL)
 168     args[2] = value_of_variable (sym, expression_context_block);
 169   else
 170     /* FIXME in this case, we should try lookup_symbol first */
 171     args[2] = value_from_longest (builtin_type_scm, SCM_EOL);
 172
 173   func = find_function_in_inferior ("scm_lookup_cstr");
 174   val = call_function_by_hand (func, 3, args);
 175   if (!value_logical_not (val))
 176     return value_ind (val);
 177
 178   sym = lookup_symbol (str,
 179                        expression_context_block,
 180                        VAR_NAMESPACE, (int *) NULL,
 181                        (struct symtab **) NULL);
 182   if (sym)
 183     return value_of_variable (sym, NULL);
 184   error ("No symbol \"%s\" in current context.");
 185 }
 186
 187 value_ptr
 188 scm_evaluate_string (str, len)
 189      char *str; int len;
 190 {
 191   value_ptr func;
 192   value_ptr addr = value_allocate_space_in_inferior (len + 1);
 193   LONGEST iaddr = value_as_long (addr);
 194   write_memory (iaddr, str, len);
 195   /* FIXME - should find and pass env */
 196   write_memory (iaddr + len, "", 1);
 197   func = find_function_in_inferior ("scm_evstr");
 198   return call_function_by_hand (func, 1, &addr);
 199 }
 200
 201 static value_ptr
 202 evaluate_subexp_scm (expect_type, exp, pos, noside)
 203      struct type *expect_type;
 204      register struct expression *exp;
 205      register int *pos;
 206      enum noside noside;
 207 {
 208   enum exp_opcode op = exp->elts[*pos].opcode;
 209   int len, pc;  char *str;
 210   switch (op)
 211     {
 212     case OP_NAME:
 213       pc = (*pos)++;
 214       len = longest_to_int (exp->elts[pc + 1].longconst);
 215       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 216       if (noside == EVAL_SKIP)
 217         goto nosideret;
 218       str = &exp->elts[pc + 2].string;
 219       return scm_lookup_name (str);
 220     case OP_EXPRSTRING:
 221       pc = (*pos)++;
 222       len = longest_to_int (exp->elts[pc + 1].longconst);
 223       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 224       if (noside == EVAL_SKIP)
 225         goto nosideret;
 226       str = &exp->elts[pc + 2].string;
 227       return scm_evaluate_string (str, len);
 228     default: ;
 229     }
 230   return evaluate_subexp_standard (expect_type, exp, pos, noside);
 231  nosideret:
 232   return value_from_longest (builtin_type_long, (LONGEST) 1);
 233 }
 234
 235 const struct language_defn scm_language_defn = {
 236   "scheme",                     /* Language name */
 237   language_scm,
 238   c_builtin_types,
 239   range_check_off,
 240   type_check_off,
 241   scm_parse,
 242   c_error,
 243   evaluate_subexp_scm,
 244   scm_printchar,                        /* Print a character constant */
 245   scm_printstr,                 /* Function to print string constant */
 246   NULL, /* Create fundamental type in this language */
 247   c_print_type,                 /* Print a type using appropriate syntax */
 248   scm_val_print,                /* Print a value using appropriate syntax */
 249   scm_value_print,              /* Print a top-level value */
 250   {"",     "",    "",  ""},     /* Binary format info */
 251   {"#o%lo",  "#o",   "o", ""},  /* Octal format info */
 252   {"%ld",   "",    "d", ""},    /* Decimal format info */
 253   {"#x%lX", "#X",  "X", ""},    /* Hex format info */
 254   NULL,                         /* expression operators for printing */
 255   1,                            /* c-style arrays */
 256   0,                            /* String lower bound */
 257   &builtin_type_char,           /* Type of string elements */
 258   LANG_MAGIC
 259 };
 260
 261 void
 262 _initialize_scheme_language ()
 263 {
 264   add_language (&scm_language_defn);
 265   builtin_type_scm = init_type (TYPE_CODE_INT,
 266                                 TARGET_LONG_BIT / TARGET_CHAR_BIT,
 267                                 0, "SCM", (struct objfile *) NULL);
 268 }