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 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
  36 extern void _initialize_scheme_language (void);
  37 static struct value *evaluate_subexp_scm (struct type *, struct expression *,
  38                                       int *, enum noside);
  39 static struct value *scm_lookup_name (char *);
  40 static int in_eval_c (void);
  41
  42 struct type *builtin_type_scm;
  43
  44 void
  45 scm_printchar (int c, struct ui_file *stream)
  46 {
  47   fprintf_filtered (stream, "#\\%c", c);
  48 }
  49
  50 static void
  51 scm_printstr (struct ui_file *stream, const gdb_byte *string,
  52               unsigned int length, int width, int force_ellipses)
  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)
  72 {
  73   gdb_byte buffer[20];
  74   read_memory (SCM2PTR (svalue) + index * TYPE_LENGTH (builtin_type_scm),
  75                buffer, TYPE_LENGTH (builtin_type_scm));
  76   return extract_signed_integer (buffer, TYPE_LENGTH (builtin_type_scm));
  77 }
  78
  79 /* Unpack a value of type TYPE in buffer VALADDR as an integer
  80    (if CONTEXT == TYPE_CODE_IN), a pointer (CONTEXT == TYPE_CODE_PTR),
  81    or Boolean (CONTEXT == TYPE_CODE_BOOL).  */
  82
  83 LONGEST
  84 scm_unpack (struct type *type, const gdb_byte *valaddr, enum type_code context)
  85 {
  86   if (is_scmvalue_type (type))
  87     {
  88       LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));
  89       if (context == TYPE_CODE_BOOL)
  90         {
  91           if (svalue == SCM_BOOL_F)
  92             return 0;
  93           else
  94             return 1;
  95         }
  96       switch (7 & (int) svalue)
  97         {
  98         case 2:
  99         case 6:         /* fixnum */
 100           return svalue >> 2;
 101         case 4:         /* other immediate value */
 102           if (SCM_ICHRP (svalue))       /* character */
 103             return SCM_ICHR (svalue);
 104           else if (SCM_IFLAGP (svalue))
 105             {
 106               switch ((int) svalue)
 107                 {
 108 #ifndef SICP
 109                 case SCM_EOL:
 110 #endif
 111                 case SCM_BOOL_F:
 112                   return 0;
 113                 case SCM_BOOL_T:
 114                   return 1;
 115                 }
 116             }
 117           error (_("Value can't be converted to integer."));
 118         default:
 119           return svalue;
 120         }
 121     }
 122   else
 123     return unpack_long (type, valaddr);
 124 }
 125
 126 /* True if we're correctly in Guile's eval.c (the evaluator and apply). */
 127
 128 static int
 129 in_eval_c (void)
 130 {
 131   struct symtab_and_line cursal = get_current_source_symtab_and_line ();
 132
 133   if (cursal.symtab && cursal.symtab->filename)
 134     {
 135       char *filename = cursal.symtab->filename;
 136       int len = strlen (filename);
 137       if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)
 138         return 1;
 139     }
 140   return 0;
 141 }
 142
 143 /* Lookup a value for the variable named STR.
 144    First lookup in Scheme context (using the scm_lookup_cstr inferior
 145    function), then try lookup_symbol for compiled variables. */
 146
 147 static struct value *
 148 scm_lookup_name (char *str)
 149 {
 150   struct value *args[3];
 151   int len = strlen (str);
 152   struct value *func;
 153   struct value *val;
 154   struct symbol *sym;
 155   args[0] = value_allocate_space_in_inferior (len);
 156   args[1] = value_from_longest (builtin_type_int, len);
 157   write_memory (value_as_long (args[0]), (gdb_byte *) str, len);
 158
 159   if (in_eval_c ()
 160       && (sym = lookup_symbol ("env",
 161                                expression_context_block,
 162                                VAR_DOMAIN, (int *) NULL,
 163                                (struct symtab **) NULL)) != NULL)
 164     args[2] = value_of_variable (sym, expression_context_block);
 165   else
 166     /* FIXME in this case, we should try lookup_symbol first */
 167     args[2] = value_from_longest (builtin_type_scm, SCM_EOL);
 168
 169   func = find_function_in_inferior ("scm_lookup_cstr");
 170   val = call_function_by_hand (func, 3, args);
 171   if (!value_logical_not (val))
 172     return value_ind (val);
 173
 174   sym = lookup_symbol (str,
 175                        expression_context_block,
 176                        VAR_DOMAIN, (int *) NULL,
 177                        (struct symtab **) 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");
 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 (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_long, (LONGEST) 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   &exp_descriptor_scm,
 246   scm_parse,
 247   c_error,
 248   null_post_parser,
 249   scm_printchar,                /* Print a character constant */
 250   scm_printstr,                 /* Function to print string constant */
 251   NULL,                         /* Function to print a single character */
 252   c_print_type,                 /* Print a type using appropriate syntax */
 253   scm_val_print,                /* Print a value using appropriate syntax */
 254   scm_value_print,              /* Print a top-level value */
 255   NULL,                         /* Language specific skip_trampoline */
 256   NULL,                         /* name_of_this */
 257   basic_lookup_symbol_nonlocal, /* lookup_symbol_nonlocal */
 258   basic_lookup_transparent_type,/* lookup_transparent_type */
 259   NULL,                         /* Language specific symbol demangler */
 260   NULL,                         /* Language specific class_name_from_physname */
 261   NULL,                         /* expression operators for printing */
 262   1,                            /* c-style arrays */
 263   0,                            /* String lower bound */
 264   default_word_break_characters,
 265   default_make_symbol_completion_list,
 266   c_language_arch_info,
 267   default_print_array_index,
 268   default_pass_by_reference,
 269   LANG_MAGIC
 270 };
 271
 272 void
 273 _initialize_scheme_language (void)
 274 {
 275   add_language (&scm_language_defn);
 276   builtin_type_scm =
 277     init_type (TYPE_CODE_INT,
 278                gdbarch_long_bit (current_gdbarch) / TARGET_CHAR_BIT,
 279                0, "SCM", (struct objfile *) NULL);
 280 }