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, 2005 Free
   4    Software 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
  44 struct type *builtin_type_scm;
  45
  46 void
  47 scm_printchar (int c, struct ui_file *stream)
  48 {
  49   fprintf_filtered (stream, "#\\%c", c);
  50 }
  51
  52 static void
  53 scm_printstr (struct ui_file *stream, const gdb_byte *string,
  54               unsigned int length, int width, int force_ellipses)
  55 {
  56   fprintf_filtered (stream, "\"%s\"", string);
  57 }
  58
  59 int
  60 is_scmvalue_type (struct type *type)
  61 {
  62   if (TYPE_CODE (type) == TYPE_CODE_INT
  63       && TYPE_NAME (type) && strcmp (TYPE_NAME (type), "SCM") == 0)
  64     {
  65       return 1;
  66     }
  67   return 0;
  68 }
  69
  70 /* Get the INDEX'th SCM value, assuming SVALUE is the address
  71    of the 0'th one.  */
  72
  73 LONGEST
  74 scm_get_field (LONGEST svalue, int index)
  75 {
  76   gdb_byte buffer[20];
  77   read_memory (SCM2PTR (svalue) + index * TYPE_LENGTH (builtin_type_scm),
  78                buffer, TYPE_LENGTH (builtin_type_scm));
  79   return extract_signed_integer (buffer, TYPE_LENGTH (builtin_type_scm));
  80 }
  81
  82 /* Unpack a value of type TYPE in buffer VALADDR as an integer
  83    (if CONTEXT == TYPE_CODE_IN), a pointer (CONTEXT == TYPE_CODE_PTR),
  84    or Boolean (CONTEXT == TYPE_CODE_BOOL).  */
  85
  86 LONGEST
  87 scm_unpack (struct type *type, const gdb_byte *valaddr, enum type_code context)
  88 {
  89   if (is_scmvalue_type (type))
  90     {
  91       LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));
  92       if (context == TYPE_CODE_BOOL)
  93         {
  94           if (svalue == SCM_BOOL_F)
  95             return 0;
  96           else
  97             return 1;
  98         }
  99       switch (7 & (int) svalue)
 100         {
 101         case 2:
 102         case 6:         /* fixnum */
 103           return svalue >> 2;
 104         case 4:         /* other immediate value */
 105           if (SCM_ICHRP (svalue))       /* character */
 106             return SCM_ICHR (svalue);
 107           else if (SCM_IFLAGP (svalue))
 108             {
 109               switch ((int) svalue)
 110                 {
 111 #ifndef SICP
 112                 case SCM_EOL:
 113 #endif
 114                 case SCM_BOOL_F:
 115                   return 0;
 116                 case SCM_BOOL_T:
 117                   return 1;
 118                 }
 119             }
 120           error (_("Value can't be converted to integer."));
 121         default:
 122           return svalue;
 123         }
 124     }
 125   else
 126     return unpack_long (type, valaddr);
 127 }
 128
 129 /* True if we're correctly in Guile's eval.c (the evaluator and apply). */
 130
 131 static int
 132 in_eval_c (void)
 133 {
 134   struct symtab_and_line cursal = get_current_source_symtab_and_line ();
 135
 136   if (cursal.symtab && cursal.symtab->filename)
 137     {
 138       char *filename = cursal.symtab->filename;
 139       int len = strlen (filename);
 140       if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)
 141         return 1;
 142     }
 143   return 0;
 144 }
 145
 146 /* Lookup a value for the variable named STR.
 147    First lookup in Scheme context (using the scm_lookup_cstr inferior
 148    function), then try lookup_symbol for compiled variables. */
 149
 150 static struct value *
 151 scm_lookup_name (char *str)
 152 {
 153   struct value *args[3];
 154   int len = strlen (str);
 155   struct value *func;
 156   struct value *val;
 157   struct symbol *sym;
 158   args[0] = value_allocate_space_in_inferior (len);
 159   args[1] = value_from_longest (builtin_type_int, len);
 160   write_memory (value_as_long (args[0]), (gdb_byte *) str, len);
 161
 162   if (in_eval_c ()
 163       && (sym = lookup_symbol ("env",
 164                                expression_context_block,
 165                                VAR_DOMAIN, (int *) NULL,
 166                                (struct symtab **) NULL)) != NULL)
 167     args[2] = value_of_variable (sym, expression_context_block);
 168   else
 169     /* FIXME in this case, we should try lookup_symbol first */
 170     args[2] = value_from_longest (builtin_type_scm, SCM_EOL);
 171
 172   func = find_function_in_inferior ("scm_lookup_cstr");
 173   val = call_function_by_hand (func, 3, args);
 174   if (!value_logical_not (val))
 175     return value_ind (val);
 176
 177   sym = lookup_symbol (str,
 178                        expression_context_block,
 179                        VAR_DOMAIN, (int *) NULL,
 180                        (struct symtab **) NULL);
 181   if (sym)
 182     return value_of_variable (sym, NULL);
 183   error (_("No symbol \"%s\" in current context."), str);
 184 }
 185
 186 struct value *
 187 scm_evaluate_string (char *str, int len)
 188 {
 189   struct value *func;
 190   struct value *addr = value_allocate_space_in_inferior (len + 1);
 191   LONGEST iaddr = value_as_long (addr);
 192   write_memory (iaddr, (gdb_byte *) str, len);
 193   /* FIXME - should find and pass env */
 194   write_memory (iaddr + len, (gdb_byte *) "", 1);
 195   func = find_function_in_inferior ("scm_evstr");
 196   return call_function_by_hand (func, 1, &addr);
 197 }
 198
 199 static struct value *
 200 evaluate_subexp_scm (struct type *expect_type, struct expression *exp,
 201                      int *pos, enum noside noside)
 202 {
 203   enum exp_opcode op = exp->elts[*pos].opcode;
 204   int len, pc;
 205   char *str;
 206   switch (op)
 207     {
 208     case OP_NAME:
 209       pc = (*pos)++;
 210       len = longest_to_int (exp->elts[pc + 1].longconst);
 211       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 212       if (noside == EVAL_SKIP)
 213         goto nosideret;
 214       str = &exp->elts[pc + 2].string;
 215       return scm_lookup_name (str);
 216     case OP_EXPRSTRING:
 217       pc = (*pos)++;
 218       len = longest_to_int (exp->elts[pc + 1].longconst);
 219       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 220       if (noside == EVAL_SKIP)
 221         goto nosideret;
 222       str = &exp->elts[pc + 2].string;
 223       return scm_evaluate_string (str, len);
 224     default:;
 225     }
 226   return evaluate_subexp_standard (expect_type, exp, pos, noside);
 227 nosideret:
 228   return value_from_longest (builtin_type_long, (LONGEST) 1);
 229 }
 230
 231 const struct exp_descriptor exp_descriptor_scm =
 232 {
 233   print_subexp_standard,
 234   operator_length_standard,
 235   op_name_standard,
 236   dump_subexp_body_standard,
 237   evaluate_subexp_scm
 238 };
 239
 240 const struct language_defn scm_language_defn =
 241 {
 242   "scheme",                     /* Language name */
 243   language_scm,
 244   NULL,
 245   range_check_off,
 246   type_check_off,
 247   case_sensitive_off,
 248   array_row_major,
 249   &exp_descriptor_scm,
 250   scm_parse,
 251   c_error,
 252   null_post_parser,
 253   scm_printchar,                /* Print a character constant */
 254   scm_printstr,                 /* Function to print string constant */
 255   NULL,                         /* Function to print a single character */
 256   NULL,                         /* Create fundamental type in this language */
 257   c_print_type,                 /* Print a type using appropriate syntax */
 258   scm_val_print,                /* Print a value using appropriate syntax */
 259   scm_value_print,              /* Print a top-level value */
 260   NULL,                         /* Language specific skip_trampoline */
 261   value_of_this,                /* value_of_this */
 262   basic_lookup_symbol_nonlocal, /* lookup_symbol_nonlocal */
 263   basic_lookup_transparent_type,/* lookup_transparent_type */
 264   NULL,                         /* Language specific symbol demangler */
 265   NULL,                         /* Language specific class_name_from_physname */
 266   NULL,                         /* expression operators for printing */
 267   1,                            /* c-style arrays */
 268   0,                            /* String lower bound */
 269   NULL,
 270   default_word_break_characters,
 271   c_language_arch_info,
 272   LANG_MAGIC
 273 };
 274
 275 void
 276 _initialize_scheme_language (void)
 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 }