gdb/scm-lang.c

   1 /* Scheme/Guile language support routines for GDB, the GNU debugger.
   2    Copyright 1995, 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 (c, stream)
  49      int c;
  50      struct ui_file *stream;
  51 {
  52   fprintf_filtered (stream, "#\\%c", c);
  53 }
  54
  55 static void
  56 scm_printstr (stream, string, length, width, force_ellipses)
  57      struct ui_file *stream;
  58      char *string;
  59      unsigned int length;
  60      int width;
  61      int force_ellipses;
  62 {
  63   fprintf_filtered (stream, "\"%s\"", string);
  64 }
  65
  66 int
  67 is_scmvalue_type (type)
  68      struct type *type;
  69 {
  70   if (TYPE_CODE (type) == TYPE_CODE_INT
  71       && TYPE_NAME (type) && strcmp (TYPE_NAME (type), "SCM") == 0)
  72     {
  73       return 1;
  74     }
  75   return 0;
  76 }
  77
  78 /* Get the INDEX'th SCM value, assuming SVALUE is the address
  79    of the 0'th one.  */
  80
  81 LONGEST
  82 scm_get_field (svalue, index)
  83      LONGEST svalue;
  84      int index;
  85 {
  86   char buffer[20];
  87   read_memory (SCM2PTR (svalue) + index * TYPE_LENGTH (builtin_type_scm),
  88                buffer, TYPE_LENGTH (builtin_type_scm));
  89   return extract_signed_integer (buffer, TYPE_LENGTH (builtin_type_scm));
  90 }
  91
  92 /* Unpack a value of type TYPE in buffer VALADDR as an integer
  93    (if CONTEXT == TYPE_CODE_IN), a pointer (CONTEXT == TYPE_CODE_PTR),
  94    or Boolean (CONTEXT == TYPE_CODE_BOOL).  */
  95
  96 LONGEST
  97 scm_unpack (type, valaddr, context)
  98      struct type *type;
  99      char *valaddr;
 100      enum type_code context;
 101 {
 102   if (is_scmvalue_type (type))
 103     {
 104       LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));
 105       if (context == TYPE_CODE_BOOL)
 106         {
 107           if (svalue == SCM_BOOL_F)
 108             return 0;
 109           else
 110             return 1;
 111         }
 112       switch (7 & (int) svalue)
 113         {
 114         case 2:
 115         case 6:         /* fixnum */
 116           return svalue >> 2;
 117         case 4:         /* other immediate value */
 118           if (SCM_ICHRP (svalue))       /* character */
 119             return SCM_ICHR (svalue);
 120           else if (SCM_IFLAGP (svalue))
 121             {
 122               switch ((int) svalue)
 123                 {
 124 #ifndef SICP
 125                 case SCM_EOL:
 126 #endif
 127                 case SCM_BOOL_F:
 128                   return 0;
 129                 case SCM_BOOL_T:
 130                   return 1;
 131                 }
 132             }
 133           error ("Value can't be converted to integer.");
 134         default:
 135           return svalue;
 136         }
 137     }
 138   else
 139     return unpack_long (type, valaddr);
 140 }
 141
 142 /* True if we're correctly in Guile's eval.c (the evaluator and apply). */
 143
 144 static int
 145 in_eval_c ()
 146 {
 147   if (current_source_symtab && current_source_symtab->filename)
 148     {
 149       char *filename = current_source_symtab->filename;
 150       int len = strlen (filename);
 151       if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)
 152         return 1;
 153     }
 154   return 0;
 155 }
 156
 157 /* Lookup a value for the variable named STR.
 158    First lookup in Scheme context (using the scm_lookup_cstr inferior
 159    function), then try lookup_symbol for compiled variables. */
 160
 161 static value_ptr
 162 scm_lookup_name (str)
 163      char *str;
 164 {
 165   value_ptr args[3];
 166   int len = strlen (str);
 167   value_ptr func, val;
 168   struct symbol *sym;
 169   args[0] = value_allocate_space_in_inferior (len);
 170   args[1] = value_from_longest (builtin_type_int, len);
 171   write_memory (value_as_long (args[0]), str, len);
 172
 173   if (in_eval_c ()
 174       && (sym = lookup_symbol ("env",
 175                                expression_context_block,
 176                                VAR_NAMESPACE, (int *) NULL,
 177                                (struct symtab **) NULL)) != NULL)
 178     args[2] = value_of_variable (sym, expression_context_block);
 179   else
 180     /* FIXME in this case, we should try lookup_symbol first */
 181     args[2] = value_from_longest (builtin_type_scm, SCM_EOL);
 182
 183   func = find_function_in_inferior ("scm_lookup_cstr");
 184   val = call_function_by_hand (func, 3, args);
 185   if (!value_logical_not (val))
 186     return value_ind (val);
 187
 188   sym = lookup_symbol (str,
 189                        expression_context_block,
 190                        VAR_NAMESPACE, (int *) NULL,
 191                        (struct symtab **) NULL);
 192   if (sym)
 193     return value_of_variable (sym, NULL);
 194   error ("No symbol \"%s\" in current context.");
 195 }
 196
 197 value_ptr
 198 scm_evaluate_string (str, len)
 199      char *str;
 200      int len;
 201 {
 202   value_ptr func;
 203   value_ptr addr = value_allocate_space_in_inferior (len + 1);
 204   LONGEST iaddr = value_as_long (addr);
 205   write_memory (iaddr, str, len);
 206   /* FIXME - should find and pass env */
 207   write_memory (iaddr + len, "", 1);
 208   func = find_function_in_inferior ("scm_evstr");
 209   return call_function_by_hand (func, 1, &addr);
 210 }
 211
 212 static value_ptr
 213 evaluate_subexp_scm (expect_type, exp, pos, noside)
 214      struct type *expect_type;
 215      register struct expression *exp;
 216      register int *pos;
 217      enum noside noside;
 218 {
 219   enum exp_opcode op = exp->elts[*pos].opcode;
 220   int len, pc;
 221   char *str;
 222   switch (op)
 223     {
 224     case OP_NAME:
 225       pc = (*pos)++;
 226       len = longest_to_int (exp->elts[pc + 1].longconst);
 227       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 228       if (noside == EVAL_SKIP)
 229         goto nosideret;
 230       str = &exp->elts[pc + 2].string;
 231       return scm_lookup_name (str);
 232     case OP_EXPRSTRING:
 233       pc = (*pos)++;
 234       len = longest_to_int (exp->elts[pc + 1].longconst);
 235       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 236       if (noside == EVAL_SKIP)
 237         goto nosideret;
 238       str = &exp->elts[pc + 2].string;
 239       return scm_evaluate_string (str, len);
 240     default:;
 241     }
 242   return evaluate_subexp_standard (expect_type, exp, pos, noside);
 243 nosideret:
 244   return value_from_longest (builtin_type_long, (LONGEST) 1);
 245 }
 246
 247 const struct language_defn scm_language_defn =
 248 {
 249   "scheme",                     /* Language name */
 250   language_scm,
 251   c_builtin_types,
 252   range_check_off,
 253   type_check_off,
 254   scm_parse,
 255   c_error,
 256   evaluate_subexp_scm,
 257   scm_printchar,                /* Print a character constant */
 258   scm_printstr,                 /* Function to print string constant */
 259   NULL,                         /* Function to print a single character */
 260   NULL,                         /* Create fundamental type in this language */
 261   c_print_type,                 /* Print a type using appropriate syntax */
 262   scm_val_print,                /* Print a value using appropriate syntax */
 263   scm_value_print,              /* Print a top-level value */
 264   {"", "", "", ""},             /* Binary format info */
 265   {"#o%lo", "#o", "o", ""},     /* Octal format info */
 266   {"%ld", "", "d", ""},         /* Decimal format info */
 267   {"#x%lX", "#X", "X", ""},     /* Hex format info */
 268   NULL,                         /* expression operators for printing */
 269   1,                            /* c-style arrays */
 270   0,                            /* String lower bound */
 271   &builtin_type_char,           /* Type of string elements */
 272   LANG_MAGIC
 273 };
 274
 275 void
 276 _initialize_scheme_language ()
 277 {
 278   add_language (&scm_language_defn);
 279   builtin_type_scm = init_type (TYPE_CODE_INT,
 280                                 TARGET_LONG_BIT / TARGET_CHAR_BIT,
 281                                 0, "SCM", (struct objfile *) NULL);
 282 }