gdb/scm-lang.c

   1 /* Scheme/Guile language support routines for GDB, the GNU debugger.
   2    Copyright 1995 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, Boston, MA 02111-1307, USA.  */
  19
  20 #include "defs.h"
  21 #include "symtab.h"
  22 #include "gdbtypes.h"
  23 #include "expression.h"
  24 #include "parser-defs.h"
  25 #include "language.h"
  26 #include "value.h"
  27 #include "c-lang.h"
  28 #include "scm-lang.h"
  29 #include "scm-tags.h"
  30 #include "gdb_string.h"
  31 #include "gdbcore.h"
  32
  33 static value_ptr evaluate_subexp_scm PARAMS ((struct type *, struct expression *,
  34                                               int *, enum noside));
  35 static value_ptr scm_lookup_name PARAMS ((char *));
  36 static int in_eval_c PARAMS ((void));
  37 static void scm_printstr PARAMS ((GDB_FILE *stream, char *string, unsigned int length, int width, int force_ellipses));
  38
  39 extern struct type ** CONST_PTR (c_builtin_types[]);
  40
  41 struct type *builtin_type_scm;
  42
  43 void
  44 scm_printchar (c, stream)
  45      int c;
  46      GDB_FILE *stream;
  47 {
  48   fprintf_filtered (stream, "#\\%c", c);
  49 }
  50
  51 static void
  52 scm_printstr (stream, string, length, width, force_ellipses)
  53      GDB_FILE *stream;
  54      char *string;
  55      unsigned int length;
  56      int width;
  57      int force_ellipses;
  58 {
  59   fprintf_filtered (stream, "\"%s\"", string);
  60 }
  61
  62 int
  63 is_scmvalue_type (type)
  64      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 (svalue, index)
  79      LONGEST svalue;
  80      int index;
  81 {
  82   char buffer[20];
  83   read_memory (SCM2PTR (svalue) + index * TYPE_LENGTH (builtin_type_scm),
  84                buffer, TYPE_LENGTH (builtin_type_scm));
  85   return extract_signed_integer (buffer, TYPE_LENGTH (builtin_type_scm));
  86 }
  87
  88 /* Unpack a value of type TYPE in buffer VALADDR as an integer
  89    (if CONTEXT == TYPE_CODE_IN), a pointer (CONTEXT == TYPE_CODE_PTR),
  90    or Boolean (CONTEXT == TYPE_CODE_BOOL).  */
  91
  92 LONGEST
  93 scm_unpack (type, valaddr, context)
  94      struct type *type;
  95      char *valaddr;
  96      enum type_code context;
  97 {
  98   if (is_scmvalue_type (type))
  99     {
 100       LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));
 101       if (context == TYPE_CODE_BOOL)
 102         {
 103           if (svalue == SCM_BOOL_F)
 104             return 0;
 105           else
 106             return 1;
 107         }
 108       switch (7 & (int) svalue)
 109         {
 110         case 2:  case 6: /* fixnum */
 111           return svalue >> 2;
 112         case 4: /* other immediate value */
 113           if (SCM_ICHRP (svalue)) /* character */
 114             return SCM_ICHR (svalue);
 115           else if (SCM_IFLAGP (svalue))
 116             {
 117               switch ((int) svalue)
 118                 {
 119 #ifndef SICP
 120                 case SCM_EOL:
 121 #endif
 122                 case SCM_BOOL_F:
 123                   return 0;
 124                 case SCM_BOOL_T:
 125                   return 1;
 126                 }
 127             }
 128           error ("Value can't be converted to integer.");
 129         default:
 130           return svalue;
 131         }
 132     }
 133   else
 134     return unpack_long (type, valaddr);
 135 }
 136
 137 /* True if we're correctly in Guile's eval.c (the evaluator and apply). */
 138
 139 static int
 140 in_eval_c ()
 141 {
 142   if (current_source_symtab && current_source_symtab->filename)
 143     {
 144       char *filename = current_source_symtab->filename;
 145       int len = strlen (filename);
 146       if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)
 147         return 1;
 148     }
 149   return 0;
 150 }
 151
 152 /* Lookup a value for the variable named STR.
 153    First lookup in Scheme context (using the scm_lookup_cstr inferior
 154    function), then try lookup_symbol for compiled variables. */
 155
 156 static value_ptr
 157 scm_lookup_name (str)
 158      char *str;
 159 {
 160   value_ptr args[3];
 161   int len = strlen (str);
 162   value_ptr func, val;
 163   struct symbol *sym;
 164   args[0] = value_allocate_space_in_inferior (len);
 165   args[1] = value_from_longest (builtin_type_int, len);
 166   write_memory (value_as_long (args[0]), str, len);
 167
 168   if (in_eval_c ()
 169       && (sym = lookup_symbol ("env",
 170                                expression_context_block,
 171                                VAR_NAMESPACE, (int *) NULL,
 172                                (struct symtab **) NULL)) != NULL)
 173     args[2] = value_of_variable (sym, expression_context_block);
 174   else
 175     /* FIXME in this case, we should try lookup_symbol first */
 176     args[2] = value_from_longest (builtin_type_scm, SCM_EOL);
 177
 178   func = find_function_in_inferior ("scm_lookup_cstr");
 179   val = call_function_by_hand (func, 3, args);
 180   if (!value_logical_not (val))
 181     return value_ind (val);
 182
 183   sym = lookup_symbol (str,
 184                        expression_context_block,
 185                        VAR_NAMESPACE, (int *) NULL,
 186                        (struct symtab **) NULL);
 187   if (sym)
 188     return value_of_variable (sym, NULL);
 189   error ("No symbol \"%s\" in current context.");
 190 }
 191
 192 value_ptr
 193 scm_evaluate_string (str, len)
 194      char *str; int len;
 195 {
 196   value_ptr func;
 197   value_ptr addr = value_allocate_space_in_inferior (len + 1);
 198   LONGEST iaddr = value_as_long (addr);
 199   write_memory (iaddr, str, len);
 200   /* FIXME - should find and pass env */
 201   write_memory (iaddr + len, "", 1);
 202   func = find_function_in_inferior ("scm_evstr");
 203   return call_function_by_hand (func, 1, &addr);
 204 }
 205
 206 static value_ptr
 207 evaluate_subexp_scm (expect_type, exp, pos, noside)
 208      struct type *expect_type;
 209      register struct expression *exp;
 210      register int *pos;
 211      enum noside noside;
 212 {
 213   enum exp_opcode op = exp->elts[*pos].opcode;
 214   int len, pc;  char *str;
 215   switch (op)
 216     {
 217     case OP_NAME:
 218       pc = (*pos)++;
 219       len = longest_to_int (exp->elts[pc + 1].longconst);
 220       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 221       if (noside == EVAL_SKIP)
 222         goto nosideret;
 223       str = &exp->elts[pc + 2].string;
 224       return scm_lookup_name (str);
 225     case OP_EXPRSTRING:
 226       pc = (*pos)++;
 227       len = longest_to_int (exp->elts[pc + 1].longconst);
 228       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 229       if (noside == EVAL_SKIP)
 230         goto nosideret;
 231       str = &exp->elts[pc + 2].string;
 232       return scm_evaluate_string (str, len);
 233     default: ;
 234     }
 235   return evaluate_subexp_standard (expect_type, exp, pos, noside);
 236  nosideret:
 237   return value_from_longest (builtin_type_long, (LONGEST) 1);
 238 }
 239
 240 const struct language_defn scm_language_defn = {
 241   "scheme",                     /* Language name */
 242   language_scm,
 243   c_builtin_types,
 244   range_check_off,
 245   type_check_off,
 246   scm_parse,
 247   c_error,
 248   evaluate_subexp_scm,
 249   scm_printchar,                /* Print a character constant */
 250   scm_printstr,                 /* Function to print string constant */
 251   NULL,                         /* Function to print a single character */
 252   NULL,                         /* Create fundamental type in this language */
 253   c_print_type,                 /* Print a type using appropriate syntax */
 254   scm_val_print,                /* Print a value using appropriate syntax */
 255   scm_value_print,              /* Print a top-level value */
 256   {"",     "",    "",  ""},     /* Binary format info */
 257   {"#o%lo",  "#o",   "o", ""},  /* Octal format info */
 258   {"%ld",   "",    "d", ""},    /* Decimal format info */
 259   {"#x%lX", "#X",  "X", ""},    /* Hex format info */
 260   NULL,                         /* expression operators for printing */
 261   1,                            /* c-style arrays */
 262   0,                            /* String lower bound */
 263   &builtin_type_char,           /* Type of string elements */
 264   LANG_MAGIC
 265 };
 266
 267 void
 268 _initialize_scheme_language ()
 269 {
 270   add_language (&scm_language_defn);
 271   builtin_type_scm = init_type (TYPE_CODE_INT,
 272                                 TARGET_LONG_BIT / TARGET_CHAR_BIT,
 273                                 0, "SCM", (struct objfile *) NULL);
 274 }