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 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 *evaluate_subexp_scm (struct type *, struct expression *,
  39                                       int *, enum noside);
  40 static struct value *scm_lookup_name (struct gdbarch *, char *);
  41 static int in_eval_c (void);
  42
  43 void
  44 scm_printchar (int c, struct type *type, struct ui_file *stream)
  45 {
  46   fprintf_filtered (stream, "#\\%c", c);
  47 }
  48
  49 static void
  50 scm_printstr (struct ui_file *stream, struct type *type, const gdb_byte *string,
  51               unsigned int length, int force_ellipses,
  52               const struct value_print_options *options)
  53 {
  54   fprintf_filtered (stream, "\"%s\"", string);
  55 }
  56
  57 int
  58 is_scmvalue_type (struct type *type)
  59 {
  60   if (TYPE_NAME (type) && strcmp (TYPE_NAME (type), "SCM") == 0)
  61     {
  62       return 1;
  63     }
  64   return 0;
  65 }
  66
  67 /* Get the INDEX'th SCM value, assuming SVALUE is the address
  68    of the 0'th one.  */
  69
  70 LONGEST
  71 scm_get_field (LONGEST svalue, int index, int size)
  72 {
  73   gdb_byte buffer[20];
  74   read_memory (SCM2PTR (svalue) + index * size, buffer, size);
  75   return extract_signed_integer (buffer, size);
  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       LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));
  88       if (context == TYPE_CODE_BOOL)
  89         {
  90           if (svalue == SCM_BOOL_F)
  91             return 0;
  92           else
  93             return 1;
  94         }
  95       switch (7 & (int) svalue)
  96         {
  97         case 2:
  98         case 6:         /* fixnum */
  99           return svalue >> 2;
 100         case 4:         /* other immediate value */
 101           if (SCM_ICHRP (svalue))       /* character */
 102             return SCM_ICHR (svalue);
 103           else if (SCM_IFLAGP (svalue))
 104             {
 105               switch ((int) svalue)
 106                 {
 107 #ifndef SICP
 108                 case SCM_EOL:
 109 #endif
 110                 case SCM_BOOL_F:
 111                   return 0;
 112                 case SCM_BOOL_T:
 113                   return 1;
 114                 }
 115             }
 116           error (_("Value can't be converted to integer."));
 117         default:
 118           return svalue;
 119         }
 120     }
 121   else
 122     return unpack_long (type, valaddr);
 123 }
 124
 125 /* True if we're correctly in Guile's eval.c (the evaluator and apply). */
 126
 127 static int
 128 in_eval_c (void)
 129 {
 130   struct symtab_and_line cursal = get_current_source_symtab_and_line ();
 131
 132   if (cursal.symtab && cursal.symtab->filename)
 133     {
 134       char *filename = cursal.symtab->filename;
 135       int len = strlen (filename);
 136       if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)
 137         return 1;
 138     }
 139   return 0;
 140 }
 141
 142 /* Lookup a value for the variable named STR.
 143    First lookup in Scheme context (using the scm_lookup_cstr inferior
 144    function), then try lookup_symbol for compiled variables. */
 145
 146 static struct value *
 147 scm_lookup_name (struct gdbarch *gdbarch, char *str)
 148 {
 149   struct value *args[3];
 150   int len = strlen (str);
 151   struct value *func;
 152   struct value *val;
 153   struct symbol *sym;
 154
 155   func = find_function_in_inferior ("scm_lookup_cstr", NULL);
 156
 157   args[0] = value_allocate_space_in_inferior (len);
 158   args[1] = value_from_longest (builtin_type (gdbarch)->builtin_int, len);
 159   write_memory (value_as_long (args[0]), (gdb_byte *) str, len);
 160
 161   if (in_eval_c ()
 162       && (sym = lookup_symbol ("env",
 163                                expression_context_block,
 164                                VAR_DOMAIN, (int *) 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_scm_type (gdbarch)->builtin_scm,
 169                                   SCM_EOL);
 170
 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_DOMAIN, (int *) NULL);
 178   if (sym)
 179     return value_of_variable (sym, NULL);
 180   error (_("No symbol \"%s\" in current context."), str);
 181 }
 182
 183 struct value *
 184 scm_evaluate_string (char *str, int len)
 185 {
 186   struct value *func;
 187   struct value *addr = value_allocate_space_in_inferior (len + 1);
 188   LONGEST iaddr = value_as_long (addr);
 189   write_memory (iaddr, (gdb_byte *) str, len);
 190   /* FIXME - should find and pass env */
 191   write_memory (iaddr + len, (gdb_byte *) "", 1);
 192   func = find_function_in_inferior ("scm_evstr", NULL);
 193   return call_function_by_hand (func, 1, &addr);
 194 }
 195
 196 static struct value *
 197 evaluate_exp (struct type *expect_type, struct expression *exp,
 198               int *pos, enum noside noside)
 199 {
 200   enum exp_opcode op = exp->elts[*pos].opcode;
 201   int len, pc;
 202   char *str;
 203   switch (op)
 204     {
 205     case OP_NAME:
 206       pc = (*pos)++;
 207       len = longest_to_int (exp->elts[pc + 1].longconst);
 208       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 209       if (noside == EVAL_SKIP)
 210         goto nosideret;
 211       str = &exp->elts[pc + 2].string;
 212       return scm_lookup_name (exp->gdbarch, str);
 213     case OP_STRING:
 214       pc = (*pos)++;
 215       len = longest_to_int (exp->elts[pc + 1].longconst);
 216       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 217       if (noside == EVAL_SKIP)
 218         goto nosideret;
 219       str = &exp->elts[pc + 2].string;
 220       return scm_evaluate_string (str, len);
 221     default:;
 222     }
 223   return evaluate_subexp_standard (expect_type, exp, pos, noside);
 224 nosideret:
 225   return value_from_longest (builtin_type (exp->gdbarch)->builtin_int, 1);
 226 }
 227
 228 const struct exp_descriptor exp_descriptor_scm =
 229 {
 230   print_subexp_standard,
 231   operator_length_standard,
 232   op_name_standard,
 233   dump_subexp_body_standard,
 234   evaluate_exp
 235 };
 236
 237 const struct language_defn scm_language_defn =
 238 {
 239   "scheme",                     /* Language name */
 240   language_scm,
 241   range_check_off,
 242   type_check_off,
 243   case_sensitive_off,
 244   array_row_major,
 245   macro_expansion_no,
 246   &exp_descriptor_scm,
 247   scm_parse,
 248   c_error,
 249   null_post_parser,
 250   scm_printchar,                /* Print a character constant */
 251   scm_printstr,                 /* Function to print string constant */
 252   NULL,                         /* Function to print a single character */
 253   c_print_type,                 /* Print a type using appropriate syntax */
 254   default_print_typedef,        /* Print a typedef using appropriate syntax */
 255   scm_val_print,                /* Print a value using appropriate syntax */
 256   scm_value_print,              /* Print a top-level value */
 257   NULL,                         /* Language specific skip_trampoline */
 258   NULL,                         /* name_of_this */
 259   basic_lookup_symbol_nonlocal, /* lookup_symbol_nonlocal */
 260   basic_lookup_transparent_type,/* lookup_transparent_type */
 261   NULL,                         /* Language specific symbol demangler */
 262   NULL,                         /* Language specific class_name_from_physname */
 263   NULL,                         /* expression operators for printing */
 264   1,                            /* c-style arrays */
 265   0,                            /* String lower bound */
 266   default_word_break_characters,
 267   default_make_symbol_completion_list,
 268   c_language_arch_info,
 269   default_print_array_index,
 270   default_pass_by_reference,
 271   default_get_string,
 272   LANG_MAGIC
 273 };
 274
 275 static void *
 276 build_scm_types (struct gdbarch *gdbarch)
 277 {
 278   struct builtin_scm_type *builtin_scm_type
 279     = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct builtin_scm_type);
 280
 281   builtin_scm_type->builtin_scm
 282     = arch_integer_type (gdbarch, gdbarch_long_bit (gdbarch), 0, "SCM");
 283
 284   return builtin_scm_type;
 285 }
 286
 287 static struct gdbarch_data *scm_type_data;
 288
 289 const struct builtin_scm_type *
 290 builtin_scm_type (struct gdbarch *gdbarch)
 291 {
 292   return gdbarch_data (gdbarch, scm_type_data);
 293 }
 294
 295 void
 296 _initialize_scheme_language (void)
 297 {
 298   scm_type_data = gdbarch_data_register_post_init (build_scm_types);
 299
 300   add_language (&scm_language_defn);
 301 }