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 #include "infcall.h"
  37
  38 extern void _initialize_scheme_language (void);
  39 static struct value *evaluate_subexp_scm (struct type *, struct expression *,
  40                                       int *, enum noside);
  41 static struct value *scm_lookup_name (char *);
  42 static int in_eval_c (void);
  43 static void scm_printstr (struct ui_file * stream, char *string,
  44                           unsigned int length, int width,
  45                           int force_ellipses);
  46
  47 extern struct type **const (c_builtin_types[]);
  48
  49 struct type *builtin_type_scm;
  50
  51 void
  52 scm_printchar (int c, struct ui_file *stream)
  53 {
  54   fprintf_filtered (stream, "#\\%c", c);
  55 }
  56
  57 static void
  58 scm_printstr (struct ui_file *stream, char *string, unsigned int length,
  59               int width, int force_ellipses)
  60 {
  61   fprintf_filtered (stream, "\"%s\"", string);
  62 }
  63
  64 int
  65 is_scmvalue_type (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 (LONGEST svalue, 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 (struct type *type, const char *valaddr, enum type_code context)
  93 {
  94   if (is_scmvalue_type (type))
  95     {
  96       LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));
  97       if (context == TYPE_CODE_BOOL)
  98         {
  99           if (svalue == SCM_BOOL_F)
 100             return 0;
 101           else
 102             return 1;
 103         }
 104       switch (7 & (int) svalue)
 105         {
 106         case 2:
 107         case 6:         /* fixnum */
 108           return svalue >> 2;
 109         case 4:         /* other immediate value */
 110           if (SCM_ICHRP (svalue))       /* character */
 111             return SCM_ICHR (svalue);
 112           else if (SCM_IFLAGP (svalue))
 113             {
 114               switch ((int) svalue)
 115                 {
 116 #ifndef SICP
 117                 case SCM_EOL:
 118 #endif
 119                 case SCM_BOOL_F:
 120                   return 0;
 121                 case SCM_BOOL_T:
 122                   return 1;
 123                 }
 124             }
 125           error ("Value can't be converted to integer.");
 126         default:
 127           return svalue;
 128         }
 129     }
 130   else
 131     return unpack_long (type, valaddr);
 132 }
 133
 134 /* True if we're correctly in Guile's eval.c (the evaluator and apply). */
 135
 136 static int
 137 in_eval_c (void)
 138 {
 139   struct symtab_and_line cursal = get_current_source_symtab_and_line ();
 140
 141   if (cursal.symtab && cursal.symtab->filename)
 142     {
 143       char *filename = cursal.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 struct value *
 156 scm_lookup_name (char *str)
 157 {
 158   struct value *args[3];
 159   int len = strlen (str);
 160   struct value *func;
 161   struct value *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_DOMAIN, (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_DOMAIN, (int *) NULL,
 185                        (struct symtab **) NULL);
 186   if (sym)
 187     return value_of_variable (sym, NULL);
 188   error ("No symbol \"%s\" in current context.", str);
 189 }
 190
 191 struct value *
 192 scm_evaluate_string (char *str, int len)
 193 {
 194   struct value *func;
 195   struct value *addr = value_allocate_space_in_inferior (len + 1);
 196   LONGEST iaddr = value_as_long (addr);
 197   write_memory (iaddr, str, len);
 198   /* FIXME - should find and pass env */
 199   write_memory (iaddr + len, "", 1);
 200   func = find_function_in_inferior ("scm_evstr");
 201   return call_function_by_hand (func, 1, &addr);
 202 }
 203
 204 static struct value *
 205 evaluate_subexp_scm (struct type *expect_type, register struct expression *exp,
 206                      register int *pos, enum noside noside)
 207 {
 208   enum exp_opcode op = exp->elts[*pos].opcode;
 209   int len, pc;
 210   char *str;
 211   switch (op)
 212     {
 213     case OP_NAME:
 214       pc = (*pos)++;
 215       len = longest_to_int (exp->elts[pc + 1].longconst);
 216       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 217       if (noside == EVAL_SKIP)
 218         goto nosideret;
 219       str = &exp->elts[pc + 2].string;
 220       return scm_lookup_name (str);
 221     case OP_EXPRSTRING:
 222       pc = (*pos)++;
 223       len = longest_to_int (exp->elts[pc + 1].longconst);
 224       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 225       if (noside == EVAL_SKIP)
 226         goto nosideret;
 227       str = &exp->elts[pc + 2].string;
 228       return scm_evaluate_string (str, len);
 229     default:;
 230     }
 231   return evaluate_subexp_standard (expect_type, exp, pos, noside);
 232 nosideret:
 233   return value_from_longest (builtin_type_long, (LONGEST) 1);
 234 }
 235
 236 const struct language_defn scm_language_defn =
 237 {
 238   "scheme",                     /* Language name */
 239   language_scm,
 240   c_builtin_types,
 241   range_check_off,
 242   type_check_off,
 243   case_sensitive_off,
 244   scm_parse,
 245   c_error,
 246   evaluate_subexp_scm,
 247   scm_printchar,                /* Print a character constant */
 248   scm_printstr,                 /* Function to print string constant */
 249   NULL,                         /* Function to print a single character */
 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   NULL,                         /* Language specific skip_trampoline */
 255   value_of_this,                /* value_of_this */
 256   basic_lookup_symbol_nonlocal, /* lookup_symbol_nonlocal */
 257   NULL,                         /* Language specific symbol demangler */
 258   {"", "", "", ""},             /* Binary format info */
 259   {"#o%lo", "#o", "o", ""},     /* Octal format info */
 260   {"%ld", "", "d", ""},         /* Decimal format info */
 261   {"#x%lX", "#X", "X", ""},     /* Hex format info */
 262   NULL,                         /* expression operators for printing */
 263   1,                            /* c-style arrays */
 264   0,                            /* String lower bound */
 265   &builtin_type_char,           /* Type of string elements */
 266   LANG_MAGIC
 267 };
 268
 269 void
 270 _initialize_scheme_language (void)
 271 {
 272   add_language (&scm_language_defn);
 273   builtin_type_scm = init_type (TYPE_CODE_INT,
 274                                 TARGET_LONG_BIT / TARGET_CHAR_BIT,
 275                                 0, "SCM", (struct objfile *) NULL);
 276 }