gdb/scm-lang.c

   1 /* Scheme/Guile language support routines for GDB, the GNU debugger.
   2
   3    Copyright (C) 1995, 1996, 1998, 2000, 2001, 2002, 2003, 2004, 2005, 2007,
   4    2008, 2009, 2010 Free 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 3 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, see <http://www.gnu.org/licenses/>.  */
  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 "source.h"
  32 #include "gdb_string.h"
  33 #include "gdbcore.h"
  34 #include "infcall.h"
  35 #include "objfiles.h"
  36
  37 extern void _initialize_scheme_language (void);
  38 static struct value *scm_lookup_name (struct gdbarch *, char *);
  39 static int in_eval_c (void);
  40
  41 void
  42 scm_printchar (int c, struct type *type, struct ui_file *stream)
  43 {
  44   fprintf_filtered (stream, "#\\%c", c);
  45 }
  46
  47 static void
  48 scm_printstr (struct ui_file *stream, struct type *type, const gdb_byte *string,
  49               unsigned int length, const char *encoding, int force_ellipses,
  50               const struct value_print_options *options)
  51 {
  52   fprintf_filtered (stream, "\"%s\"", string);
  53 }
  54
  55 int
  56 is_scmvalue_type (struct type *type)
  57 {
  58   if (TYPE_NAME (type) && strcmp (TYPE_NAME (type), "SCM") == 0)
  59     {
  60       return 1;
  61     }
  62   return 0;
  63 }
  64
  65 /* Get the INDEX'th SCM value, assuming SVALUE is the address
  66    of the 0'th one.  */
  67
  68 LONGEST
  69 scm_get_field (LONGEST svalue, int index, int size,
  70                enum bfd_endian byte_order)
  71 {
  72   gdb_byte buffer[20];
  73
  74   read_memory (SCM2PTR (svalue) + index * size, buffer, size);
  75   return extract_signed_integer (buffer, size, byte_order);
  76 }
  77
  78 /* Unpack a value of type TYPE in buffer VALADDR as an integer
  79    (if CONTEXT == TYPE_CODE_IN), a pointer (CONTEXT == TYPE_CODE_PTR),
  80    or Boolean (CONTEXT == TYPE_CODE_BOOL).  */
  81
  82 LONGEST
  83 scm_unpack (struct type *type, const gdb_byte *valaddr, enum type_code context)
  84 {
  85   if (is_scmvalue_type (type))
  86     {
  87       enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
  88       LONGEST svalue
  89         = extract_signed_integer (valaddr, TYPE_LENGTH (type), byte_order);
  90
  91       if (context == TYPE_CODE_BOOL)
  92         {
  93           if (svalue == SCM_BOOL_F)
  94             return 0;
  95           else
  96             return 1;
  97         }
  98       switch (7 & (int) svalue)
  99         {
 100         case 2:
 101         case 6:         /* fixnum */
 102           return svalue >> 2;
 103         case 4:         /* other immediate value */
 104           if (SCM_ICHRP (svalue))       /* character */
 105             return SCM_ICHR (svalue);
 106           else if (SCM_IFLAGP (svalue))
 107             {
 108               switch ((int) svalue)
 109                 {
 110 #ifndef SICP
 111                 case SCM_EOL:
 112 #endif
 113                 case SCM_BOOL_F:
 114                   return 0;
 115                 case SCM_BOOL_T:
 116                   return 1;
 117                 }
 118             }
 119           error (_("Value can't be converted to integer."));
 120         default:
 121           return svalue;
 122         }
 123     }
 124   else
 125     return unpack_long (type, valaddr);
 126 }
 127
 128 /* True if we're correctly in Guile's eval.c (the evaluator and apply). */
 129
 130 static int
 131 in_eval_c (void)
 132 {
 133   struct symtab_and_line cursal = get_current_source_symtab_and_line ();
 134
 135   if (cursal.symtab && cursal.symtab->filename)
 136     {
 137       char *filename = cursal.symtab->filename;
 138       int len = strlen (filename);
 139
 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 (struct gdbarch *gdbarch, 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
 159   func = find_function_in_inferior ("scm_lookup_cstr", NULL);
 160
 161   args[0] = value_allocate_space_in_inferior (len);
 162   args[1] = value_from_longest (builtin_type (gdbarch)->builtin_int, len);
 163   write_memory (value_as_long (args[0]), (gdb_byte *) str, len);
 164
 165   if (in_eval_c ()
 166       && (sym = lookup_symbol ("env",
 167                                expression_context_block,
 168                                VAR_DOMAIN, (int *) NULL)) != NULL)
 169     args[2] = value_of_variable (sym, expression_context_block);
 170   else
 171     /* FIXME in this case, we should try lookup_symbol first */
 172     args[2] = value_from_longest (builtin_scm_type (gdbarch)->builtin_scm,
 173                                   SCM_EOL);
 174
 175   val = call_function_by_hand (func, 3, args);
 176   if (!value_logical_not (val))
 177     return value_ind (val);
 178
 179   sym = lookup_symbol (str,
 180                        expression_context_block,
 181                        VAR_DOMAIN, (int *) NULL);
 182   if (sym)
 183     return value_of_variable (sym, NULL);
 184   error (_("No symbol \"%s\" in current context."), str);
 185 }
 186
 187 struct value *
 188 scm_evaluate_string (char *str, int len)
 189 {
 190   struct value *func;
 191   struct value *addr = value_allocate_space_in_inferior (len + 1);
 192   LONGEST iaddr = value_as_long (addr);
 193
 194   write_memory (iaddr, (gdb_byte *) str, len);
 195   /* FIXME - should find and pass env */
 196   write_memory (iaddr + len, (gdb_byte *) "", 1);
 197   func = find_function_in_inferior ("scm_evstr", NULL);
 198   return call_function_by_hand (func, 1, &addr);
 199 }
 200
 201 static struct value *
 202 evaluate_exp (struct type *expect_type, struct expression *exp,
 203               int *pos, enum noside noside)
 204 {
 205   enum exp_opcode op = exp->elts[*pos].opcode;
 206   int len, pc;
 207   char *str;
 208
 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 (exp->gdbarch, str);
 219     case OP_STRING:
 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 (exp->gdbarch)->builtin_int, 1);
 232 }
 233
 234 const struct exp_descriptor exp_descriptor_scm =
 235 {
 236   print_subexp_standard,
 237   operator_length_standard,
 238   operator_check_standard,
 239   op_name_standard,
 240   dump_subexp_body_standard,
 241   evaluate_exp
 242 };
 243
 244 const struct language_defn scm_language_defn =
 245 {
 246   "scheme",                     /* Language name */
 247   language_scm,
 248   range_check_off,
 249   type_check_off,
 250   case_sensitive_off,
 251   array_row_major,
 252   macro_expansion_no,
 253   &exp_descriptor_scm,
 254   scm_parse,
 255   c_error,
 256   null_post_parser,
 257   scm_printchar,                /* Print a character constant */
 258   scm_printstr,                 /* Function to print string constant */
 259   NULL,                         /* Function to print a single character */
 260   c_print_type,                 /* Print a type using appropriate syntax */
 261   default_print_typedef,        /* Print a typedef using appropriate syntax */
 262   scm_val_print,                /* Print a value using appropriate syntax */
 263   scm_value_print,              /* Print a top-level value */
 264   NULL,                         /* Language specific skip_trampoline */
 265   NULL,                         /* name_of_this */
 266   basic_lookup_symbol_nonlocal, /* lookup_symbol_nonlocal */
 267   basic_lookup_transparent_type,/* lookup_transparent_type */
 268   NULL,                         /* Language specific symbol demangler */
 269   NULL,                         /* Language specific class_name_from_physname */
 270   NULL,                         /* expression operators for printing */
 271   1,                            /* c-style arrays */
 272   0,                            /* String lower bound */
 273   default_word_break_characters,
 274   default_make_symbol_completion_list,
 275   c_language_arch_info,
 276   default_print_array_index,
 277   default_pass_by_reference,
 278   default_get_string,
 279   LANG_MAGIC
 280 };
 281
 282 static void *
 283 build_scm_types (struct gdbarch *gdbarch)
 284 {
 285   struct builtin_scm_type *builtin_scm_type
 286     = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct builtin_scm_type);
 287
 288   builtin_scm_type->builtin_scm
 289     = arch_integer_type (gdbarch, gdbarch_long_bit (gdbarch), 0, "SCM");
 290
 291   return builtin_scm_type;
 292 }
 293
 294 static struct gdbarch_data *scm_type_data;
 295
 296 const struct builtin_scm_type *
 297 builtin_scm_type (struct gdbarch *gdbarch)
 298 {
 299   return gdbarch_data (gdbarch, scm_type_data);
 300 }
 301
 302 void
 303 _initialize_scheme_language (void)
 304 {
 305   scm_type_data = gdbarch_data_register_post_init (build_scm_types);
 306
 307   add_language (&scm_language_defn);
 308 }