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, 2004 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 struct type *builtin_type_scm;
  48
  49 void
  50 scm_printchar (int c, struct ui_file *stream)
  51 {
  52   fprintf_filtered (stream, "#\\%c", c);
  53 }
  54
  55 static void
  56 scm_printstr (struct ui_file *stream, char *string, unsigned int length,
  57               int width, int force_ellipses)
  58 {
  59   fprintf_filtered (stream, "\"%s\"", string);
  60 }
  61
  62 int
  63 is_scmvalue_type (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 (LONGEST svalue, int index)
  78 {
  79   char buffer[20];
  80   read_memory (SCM2PTR (svalue) + index * TYPE_LENGTH (builtin_type_scm),
  81                buffer, TYPE_LENGTH (builtin_type_scm));
  82   return extract_signed_integer (buffer, TYPE_LENGTH (builtin_type_scm));
  83 }
  84
  85 /* Unpack a value of type TYPE in buffer VALADDR as an integer
  86    (if CONTEXT == TYPE_CODE_IN), a pointer (CONTEXT == TYPE_CODE_PTR),
  87    or Boolean (CONTEXT == TYPE_CODE_BOOL).  */
  88
  89 LONGEST
  90 scm_unpack (struct type *type, const char *valaddr, enum type_code context)
  91 {
  92   if (is_scmvalue_type (type))
  93     {
  94       LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));
  95       if (context == TYPE_CODE_BOOL)
  96         {
  97           if (svalue == SCM_BOOL_F)
  98             return 0;
  99           else
 100             return 1;
 101         }
 102       switch (7 & (int) svalue)
 103         {
 104         case 2:
 105         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 ((int) 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 (void)
 136 {
 137   struct symtab_and_line cursal = get_current_source_symtab_and_line ();
 138
 139   if (cursal.symtab && cursal.symtab->filename)
 140     {
 141       char *filename = cursal.symtab->filename;
 142       int len = strlen (filename);
 143       if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)
 144         return 1;
 145     }
 146   return 0;
 147 }
 148
 149 /* Lookup a value for the variable named STR.
 150    First lookup in Scheme context (using the scm_lookup_cstr inferior
 151    function), then try lookup_symbol for compiled variables. */
 152
 153 static struct value *
 154 scm_lookup_name (char *str)
 155 {
 156   struct value *args[3];
 157   int len = strlen (str);
 158   struct value *func;
 159   struct value *val;
 160   struct symbol *sym;
 161   args[0] = value_allocate_space_in_inferior (len);
 162   args[1] = value_from_longest (builtin_type_int, len);
 163   write_memory (value_as_long (args[0]), str, len);
 164
 165   if (in_eval_c ()
 166       && (sym = lookup_symbol ("env",
 167                                expression_context_block,
 168                                VAR_DOMAIN, (int *) NULL,
 169                                (struct symtab **) NULL)) != NULL)
 170     args[2] = value_of_variable (sym, expression_context_block);
 171   else
 172     /* FIXME in this case, we should try lookup_symbol first */
 173     args[2] = value_from_longest (builtin_type_scm, SCM_EOL);
 174
 175   func = find_function_in_inferior ("scm_lookup_cstr");
 176   val = call_function_by_hand (func, 3, args);
 177   if (!value_logical_not (val))
 178     return value_ind (val);
 179
 180   sym = lookup_symbol (str,
 181                        expression_context_block,
 182                        VAR_DOMAIN, (int *) NULL,
 183                        (struct symtab **) NULL);
 184   if (sym)
 185     return value_of_variable (sym, NULL);
 186   error ("No symbol \"%s\" in current context.", str);
 187 }
 188
 189 struct value *
 190 scm_evaluate_string (char *str, int len)
 191 {
 192   struct value *func;
 193   struct value *addr = value_allocate_space_in_inferior (len + 1);
 194   LONGEST iaddr = value_as_long (addr);
 195   write_memory (iaddr, str, len);
 196   /* FIXME - should find and pass env */
 197   write_memory (iaddr + len, "", 1);
 198   func = find_function_in_inferior ("scm_evstr");
 199   return call_function_by_hand (func, 1, &addr);
 200 }
 201
 202 static struct value *
 203 evaluate_subexp_scm (struct type *expect_type, struct expression *exp,
 204                      int *pos, enum noside noside)
 205 {
 206   enum exp_opcode op = exp->elts[*pos].opcode;
 207   int len, pc;
 208   char *str;
 209   switch (op)
 210     {
 211     case OP_NAME:
 212       pc = (*pos)++;
 213       len = longest_to_int (exp->elts[pc + 1].longconst);
 214       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 215       if (noside == EVAL_SKIP)
 216         goto nosideret;
 217       str = &exp->elts[pc + 2].string;
 218       return scm_lookup_name (str);
 219     case OP_EXPRSTRING:
 220       pc = (*pos)++;
 221       len = longest_to_int (exp->elts[pc + 1].longconst);
 222       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 223       if (noside == EVAL_SKIP)
 224         goto nosideret;
 225       str = &exp->elts[pc + 2].string;
 226       return scm_evaluate_string (str, len);
 227     default:;
 228     }
 229   return evaluate_subexp_standard (expect_type, exp, pos, noside);
 230 nosideret:
 231   return value_from_longest (builtin_type_long, (LONGEST) 1);
 232 }
 233
 234 const struct exp_descriptor exp_descriptor_scm =
 235 {
 236   print_subexp_standard,
 237   operator_length_standard,
 238   op_name_standard,
 239   dump_subexp_body_standard,
 240   evaluate_subexp_scm
 241 };
 242
 243 const struct language_defn scm_language_defn =
 244 {
 245   "scheme",                     /* Language name */
 246   language_scm,
 247   NULL,
 248   range_check_off,
 249   type_check_off,
 250   case_sensitive_off,
 251   array_row_major,
 252   &exp_descriptor_scm,
 253   scm_parse,
 254   c_error,
 255   null_post_parser,
 256   scm_printchar,                /* Print a character constant */
 257   scm_printstr,                 /* Function to print string constant */
 258   NULL,                         /* Function to print a single character */
 259   NULL,                         /* Create fundamental type in this language */
 260   c_print_type,                 /* Print a type using appropriate syntax */
 261   scm_val_print,                /* Print a value using appropriate syntax */
 262   scm_value_print,              /* Print a top-level value */
 263   NULL,                         /* Language specific skip_trampoline */
 264   value_of_this,                /* value_of_this */
 265   basic_lookup_symbol_nonlocal, /* lookup_symbol_nonlocal */
 266   basic_lookup_transparent_type,/* lookup_transparent_type */
 267   NULL,                         /* Language specific symbol demangler */
 268   NULL,                         /* Language specific class_name_from_physname */
 269   NULL,                         /* expression operators for printing */
 270   1,                            /* c-style arrays */
 271   0,                            /* String lower bound */
 272   NULL,
 273   default_word_break_characters,
 274   c_language_arch_info,
 275   LANG_MAGIC
 276 };
 277
 278 void
 279 _initialize_scheme_language (void)
 280 {
 281   add_language (&scm_language_defn);
 282   builtin_type_scm = init_type (TYPE_CODE_INT,
 283                                 TARGET_LONG_BIT / TARGET_CHAR_BIT,
 284                                 0, "SCM", (struct objfile *) NULL);
 285 }