gdb/scm-lang.c

   1 /* Scheme/Guile language support routines for GDB, the GNU debugger.
   2    Copyright 1995, 1996, 1998, 2000 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,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include "defs.h"
  22 #include "symtab.h"
  23 #include "gdbtypes.h"
  24 #include "expression.h"
  25 #include "parser-defs.h"
  26 #include "language.h"
  27 #include "value.h"
  28 #include "c-lang.h"
  29 #include "scm-lang.h"
  30 #include "scm-tags.h"
  31 #include "gdb_string.h"
  32 #include "gdbcore.h"
  33
  34 extern void _initialize_scheme_language (void);
  35 static value_ptr evaluate_subexp_scm (struct type *, struct expression *,
  36                                       int *, enum noside);
  37 static value_ptr scm_lookup_name (char *);
  38 static int in_eval_c (void);
  39 static void scm_printstr (struct ui_file * stream, char *string,
  40                           unsigned int length, int width,
  41                           int force_ellipses);
  42
  43 extern struct type **CONST_PTR (c_builtin_types[]);
  44
  45 struct type *builtin_type_scm;
  46
  47 void
  48 scm_printchar (int c, struct ui_file *stream)
  49 {
  50   fprintf_filtered (stream, "#\\%c", c);
  51 }
  52
  53 static void
  54 scm_printstr (struct ui_file *stream, char *string, unsigned int length,
  55               int width, int force_ellipses)
  56 {
  57   fprintf_filtered (stream, "\"%s\"", string);
  58 }
  59
  60 int
  61 is_scmvalue_type (struct type *type)
  62 {
  63   if (TYPE_CODE (type) == TYPE_CODE_INT
  64       && TYPE_NAME (type) && strcmp (TYPE_NAME (type), "SCM") == 0)
  65     {
  66       return 1;
  67     }
  68   return 0;
  69 }
  70
  71 /* Get the INDEX'th SCM value, assuming SVALUE is the address
  72    of the 0'th one.  */
  73
  74 LONGEST
  75 scm_get_field (LONGEST svalue, int index)
  76 {
  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 (struct type *type, char *valaddr, enum type_code context)
  89 {
  90   if (is_scmvalue_type (type))
  91     {
  92       LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));
  93       if (context == TYPE_CODE_BOOL)
  94         {
  95           if (svalue == SCM_BOOL_F)
  96             return 0;
  97           else
  98             return 1;
  99         }
 100       switch (7 & (int) svalue)
 101         {
 102         case 2:
 103         case 6:         /* fixnum */
 104           return svalue >> 2;
 105         case 4:         /* other immediate value */
 106           if (SCM_ICHRP (svalue))       /* character */
 107             return SCM_ICHR (svalue);
 108           else if (SCM_IFLAGP (svalue))
 109             {
 110               switch ((int) svalue)
 111                 {
 112 #ifndef SICP
 113                 case SCM_EOL:
 114 #endif
 115                 case SCM_BOOL_F:
 116                   return 0;
 117                 case SCM_BOOL_T:
 118                   return 1;
 119                 }
 120             }
 121           error ("Value can't be converted to integer.");
 122         default:
 123           return svalue;
 124         }
 125     }
 126   else
 127     return unpack_long (type, valaddr);
 128 }
 129
 130 /* True if we're correctly in Guile's eval.c (the evaluator and apply). */
 131
 132 static int
 133 in_eval_c (void)
 134 {
 135   if (current_source_symtab && current_source_symtab->filename)
 136     {
 137       char *filename = current_source_symtab->filename;
 138       int len = strlen (filename);
 139       if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)
 140         return 1;
 141     }
 142   return 0;
 143 }
 144
 145 /* Lookup a value for the variable named STR.
 146    First lookup in Scheme context (using the scm_lookup_cstr inferior
 147    function), then try lookup_symbol for compiled variables. */
 148
 149 static value_ptr
 150 scm_lookup_name (char *str)
 151 {
 152   value_ptr args[3];
 153   int len = strlen (str);
 154   value_ptr func, val;
 155   struct symbol *sym;
 156   args[0] = value_allocate_space_in_inferior (len);
 157   args[1] = value_from_longest (builtin_type_int, len);
 158   write_memory (value_as_long (args[0]), str, len);
 159
 160   if (in_eval_c ()
 161       && (sym = lookup_symbol ("env",
 162                                expression_context_block,
 163                                VAR_NAMESPACE, (int *) NULL,
 164                                (struct symtab **) NULL)) != NULL)
 165     args[2] = value_of_variable (sym, expression_context_block);
 166   else
 167     /* FIXME in this case, we should try lookup_symbol first */
 168     args[2] = value_from_longest (builtin_type_scm, SCM_EOL);
 169
 170   func = find_function_in_inferior ("scm_lookup_cstr");
 171   val = call_function_by_hand (func, 3, args);
 172   if (!value_logical_not (val))
 173     return value_ind (val);
 174
 175   sym = lookup_symbol (str,
 176                        expression_context_block,
 177                        VAR_NAMESPACE, (int *) NULL,
 178                        (struct symtab **) NULL);
 179   if (sym)
 180     return value_of_variable (sym, NULL);
 181   error ("No symbol \"%s\" in current context.");
 182 }
 183
 184 value_ptr
 185 scm_evaluate_string (char *str, int len)
 186 {
 187   value_ptr func;
 188   value_ptr addr = value_allocate_space_in_inferior (len + 1);
 189   LONGEST iaddr = value_as_long (addr);
 190   write_memory (iaddr, str, len);
 191   /* FIXME - should find and pass env */
 192   write_memory (iaddr + len, "", 1);
 193   func = find_function_in_inferior ("scm_evstr");
 194   return call_function_by_hand (func, 1, &addr);
 195 }
 196
 197 static value_ptr
 198 evaluate_subexp_scm (struct type *expect_type, register struct expression *exp,
 199                      register int *pos, enum noside noside)
 200 {
 201   enum exp_opcode op = exp->elts[*pos].opcode;
 202   int len, pc;
 203   char *str;
 204   switch (op)
 205     {
 206     case OP_NAME:
 207       pc = (*pos)++;
 208       len = longest_to_int (exp->elts[pc + 1].longconst);
 209       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 210       if (noside == EVAL_SKIP)
 211         goto nosideret;
 212       str = &exp->elts[pc + 2].string;
 213       return scm_lookup_name (str);
 214     case OP_EXPRSTRING:
 215       pc = (*pos)++;
 216       len = longest_to_int (exp->elts[pc + 1].longconst);
 217       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 218       if (noside == EVAL_SKIP)
 219         goto nosideret;
 220       str = &exp->elts[pc + 2].string;
 221       return scm_evaluate_string (str, len);
 222     default:;
 223     }
 224   return evaluate_subexp_standard (expect_type, exp, pos, noside);
 225 nosideret:
 226   return value_from_longest (builtin_type_long, (LONGEST) 1);
 227 }
 228
 229 const struct language_defn scm_language_defn =
 230 {
 231   "scheme",                     /* Language name */
 232   language_scm,
 233   c_builtin_types,
 234   range_check_off,
 235   type_check_off,
 236   case_sensitive_off,
 237   scm_parse,
 238   c_error,
 239   evaluate_subexp_scm,
 240   scm_printchar,                /* Print a character constant */
 241   scm_printstr,                 /* Function to print string constant */
 242   NULL,                         /* Function to print a single character */
 243   NULL,                         /* Create fundamental type in this language */
 244   c_print_type,                 /* Print a type using appropriate syntax */
 245   scm_val_print,                /* Print a value using appropriate syntax */
 246   scm_value_print,              /* Print a top-level value */
 247   {"", "", "", ""},             /* Binary format info */
 248   {"#o%lo", "#o", "o", ""},     /* Octal format info */
 249   {"%ld", "", "d", ""},         /* Decimal format info */
 250   {"#x%lX", "#X", "X", ""},     /* Hex format info */
 251   NULL,                         /* expression operators for printing */
 252   1,                            /* c-style arrays */
 253   0,                            /* String lower bound */
 254   &builtin_type_char,           /* Type of string elements */
 255   LANG_MAGIC
 256 };
 257
 258 void
 259 _initialize_scheme_language (void)
 260 {
 261   add_language (&scm_language_defn);
 262   builtin_type_scm = init_type (TYPE_CODE_INT,
 263                                 TARGET_LONG_BIT / TARGET_CHAR_BIT,
 264                                 0, "SCM", (struct objfile *) NULL);
 265 }