gdb/scm-lang.c

   1 /* Scheme/Guile language support routines for GDB, the GNU debugger.
   2
   3    Copyright 1995, 1996, 1998, 2000, 2001, 2002, 2003 Free Software
   4    Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #include "defs.h"
  24 #include "symtab.h"
  25 #include "gdbtypes.h"
  26 #include "expression.h"
  27 #include "parser-defs.h"
  28 #include "language.h"
  29 #include "value.h"
  30 #include "c-lang.h"
  31 #include "scm-lang.h"
  32 #include "scm-tags.h"
  33 #include "source.h"
  34 #include "gdb_string.h"
  35 #include "gdbcore.h"
  36
  37 extern void _initialize_scheme_language (void);
  38 static struct value *evaluate_subexp_scm (struct type *, struct expression *,
  39                                       int *, enum noside);
  40 static struct value *scm_lookup_name (char *);
  41 static int in_eval_c (void);
  42 static void scm_printstr (struct ui_file * stream, char *string,
  43                           unsigned int length, int width,
  44                           int force_ellipses);
  45
  46 extern struct type **const (c_builtin_types[]);
  47
  48 struct type *builtin_type_scm;
  49
  50 void
  51 scm_printchar (int c, struct ui_file *stream)
  52 {
  53   fprintf_filtered (stream, "#\\%c", c);
  54 }
  55
  56 static void
  57 scm_printstr (struct ui_file *stream, char *string, unsigned int length,
  58               int width, int force_ellipses)
  59 {
  60   fprintf_filtered (stream, "\"%s\"", string);
  61 }
  62
  63 int
  64 is_scmvalue_type (struct type *type)
  65 {
  66   if (TYPE_CODE (type) == TYPE_CODE_INT
  67       && TYPE_NAME (type) && strcmp (TYPE_NAME (type), "SCM") == 0)
  68     {
  69       return 1;
  70     }
  71   return 0;
  72 }
  73
  74 /* Get the INDEX'th SCM value, assuming SVALUE is the address
  75    of the 0'th one.  */
  76
  77 LONGEST
  78 scm_get_field (LONGEST svalue, int index)
  79 {
  80   char buffer[20];
  81   read_memory (SCM2PTR (svalue) + index * TYPE_LENGTH (builtin_type_scm),
  82                buffer, TYPE_LENGTH (builtin_type_scm));
  83   return extract_signed_integer (buffer, TYPE_LENGTH (builtin_type_scm));
  84 }
  85
  86 /* Unpack a value of type TYPE in buffer VALADDR as an integer
  87    (if CONTEXT == TYPE_CODE_IN), a pointer (CONTEXT == TYPE_CODE_PTR),
  88    or Boolean (CONTEXT == TYPE_CODE_BOOL).  */
  89
  90 LONGEST
  91 scm_unpack (struct type *type, const char *valaddr, 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 & (int) svalue)
 104         {
 105         case 2:
 106         case 6:         /* fixnum */
 107           return svalue >> 2;
 108         case 4:         /* other immediate value */
 109           if (SCM_ICHRP (svalue))       /* character */
 110             return SCM_ICHR (svalue);
 111           else if (SCM_IFLAGP (svalue))
 112             {
 113               switch ((int) svalue)
 114                 {
 115 #ifndef SICP
 116                 case SCM_EOL:
 117 #endif
 118                 case SCM_BOOL_F:
 119                   return 0;
 120                 case SCM_BOOL_T:
 121                   return 1;
 122                 }
 123             }
 124           error ("Value can't be converted to integer.");
 125         default:
 126           return svalue;
 127         }
 128     }
 129   else
 130     return unpack_long (type, valaddr);
 131 }
 132
 133 /* True if we're correctly in Guile's eval.c (the evaluator and apply). */
 134
 135 static int
 136 in_eval_c (void)
 137 {
 138   struct symtab_and_line cursal = get_current_source_symtab_and_line ();
 139
 140   if (cursal.symtab && cursal.symtab->filename)
 141     {
 142       char *filename = cursal.symtab->filename;
 143       int len = strlen (filename);
 144       if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)
 145         return 1;
 146     }
 147   return 0;
 148 }
 149
 150 /* Lookup a value for the variable named STR.
 151    First lookup in Scheme context (using the scm_lookup_cstr inferior
 152    function), then try lookup_symbol for compiled variables. */
 153
 154 static struct value *
 155 scm_lookup_name (char *str)
 156 {
 157   struct value *args[3];
 158   int len = strlen (str);
 159   struct value *func;
 160   struct value *val;
 161   struct symbol *sym;
 162   args[0] = value_allocate_space_in_inferior (len);
 163   args[1] = value_from_longest (builtin_type_int, len);
 164   write_memory (value_as_long (args[0]), str, len);
 165
 166   if (in_eval_c ()
 167       && (sym = lookup_symbol ("env",
 168                                expression_context_block,
 169                                VAR_NAMESPACE, (int *) NULL,
 170                                (struct symtab **) NULL)) != NULL)
 171     args[2] = value_of_variable (sym, expression_context_block);
 172   else
 173     /* FIXME in this case, we should try lookup_symbol first */
 174     args[2] = value_from_longest (builtin_type_scm, SCM_EOL);
 175
 176   func = find_function_in_inferior ("scm_lookup_cstr");
 177   val = call_function_by_hand (func, 3, args);
 178   if (!value_logical_not (val))
 179     return value_ind (val);
 180
 181   sym = lookup_symbol (str,
 182                        expression_context_block,
 183                        VAR_NAMESPACE, (int *) NULL,
 184                        (struct symtab **) NULL);
 185   if (sym)
 186     return value_of_variable (sym, NULL);
 187   error ("No symbol \"%s\" in current context.", str);
 188 }
 189
 190 struct value *
 191 scm_evaluate_string (char *str, int len)
 192 {
 193   struct value *func;
 194   struct value *addr = value_allocate_space_in_inferior (len + 1);
 195   LONGEST iaddr = value_as_long (addr);
 196   write_memory (iaddr, str, len);
 197   /* FIXME - should find and pass env */
 198   write_memory (iaddr + len, "", 1);
 199   func = find_function_in_inferior ("scm_evstr");
 200   return call_function_by_hand (func, 1, &addr);
 201 }
 202
 203 static struct value *
 204 evaluate_subexp_scm (struct type *expect_type, register struct expression *exp,
 205                      register int *pos, enum noside noside)
 206 {
 207   enum exp_opcode op = exp->elts[*pos].opcode;
 208   int len, pc;
 209   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 {
 237   "scheme",                     /* Language name */
 238   language_scm,
 239   c_builtin_types,
 240   range_check_off,
 241   type_check_off,
 242   case_sensitive_off,
 243   scm_parse,
 244   c_error,
 245   evaluate_subexp_scm,
 246   scm_printchar,                /* Print a character constant */
 247   scm_printstr,                 /* Function to print string constant */
 248   NULL,                         /* Function to print a single character */
 249   NULL,                         /* Create fundamental type in this language */
 250   c_print_type,                 /* Print a type using appropriate syntax */
 251   scm_val_print,                /* Print a value using appropriate syntax */
 252   scm_value_print,              /* Print a top-level value */
 253   NULL,                         /* Language specific skip_trampoline */
 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 (void)
 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 }