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 #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 (char *);
  41 static int in_eval_c (void);
  42
  43 struct type *builtin_type_scm;
  44
  45 void
  46 scm_printchar (int c, struct ui_file *stream)
  47 {
  48   fprintf_filtered (stream, "#\\%c", c);
  49 }
  50
  51 static void
  52 scm_printstr (struct ui_file *stream, const gdb_byte *string,
  53               unsigned int length, int width, int force_ellipses)
  54 {
  55   fprintf_filtered (stream, "\"%s\"", string);
  56 }
  57
  58 int
  59 is_scmvalue_type (struct type *type)
  60 {
  61   if (TYPE_NAME (type) && strcmp (TYPE_NAME (type), "SCM") == 0)
  62     {
  63       return 1;
  64     }
  65   return 0;
  66 }
  67
  68 /* Get the INDEX'th SCM value, assuming SVALUE is the address
  69    of the 0'th one.  */
  70
  71 LONGEST
  72 scm_get_field (LONGEST svalue, int index)
  73 {
  74   gdb_byte buffer[20];
  75   read_memory (SCM2PTR (svalue) + index * TYPE_LENGTH (builtin_type_scm),
  76                buffer, TYPE_LENGTH (builtin_type_scm));
  77   return extract_signed_integer (buffer, TYPE_LENGTH (builtin_type_scm));
  78 }
  79
  80 /* Unpack a value of type TYPE in buffer VALADDR as an integer
  81    (if CONTEXT == TYPE_CODE_IN), a pointer (CONTEXT == TYPE_CODE_PTR),
  82    or Boolean (CONTEXT == TYPE_CODE_BOOL).  */
  83
  84 LONGEST
  85 scm_unpack (struct type *type, const gdb_byte *valaddr, enum type_code context)
  86 {
  87   if (is_scmvalue_type (type))
  88     {
  89       LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));
  90       if (context == TYPE_CODE_BOOL)
  91         {
  92           if (svalue == SCM_BOOL_F)
  93             return 0;
  94           else
  95             return 1;
  96         }
  97       switch (7 & (int) svalue)
  98         {
  99         case 2:
 100         case 6:         /* fixnum */
 101           return svalue >> 2;
 102         case 4:         /* other immediate value */
 103           if (SCM_ICHRP (svalue))       /* character */
 104             return SCM_ICHR (svalue);
 105           else if (SCM_IFLAGP (svalue))
 106             {
 107               switch ((int) svalue)
 108                 {
 109 #ifndef SICP
 110                 case SCM_EOL:
 111 #endif
 112                 case SCM_BOOL_F:
 113                   return 0;
 114                 case SCM_BOOL_T:
 115                   return 1;
 116                 }
 117             }
 118           error (_("Value can't be converted to integer."));
 119         default:
 120           return svalue;
 121         }
 122     }
 123   else
 124     return unpack_long (type, valaddr);
 125 }
 126
 127 /* True if we're correctly in Guile's eval.c (the evaluator and apply). */
 128
 129 static int
 130 in_eval_c (void)
 131 {
 132   struct symtab_and_line cursal = get_current_source_symtab_and_line ();
 133
 134   if (cursal.symtab && cursal.symtab->filename)
 135     {
 136       char *filename = cursal.symtab->filename;
 137       int len = strlen (filename);
 138       if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)
 139         return 1;
 140     }
 141   return 0;
 142 }
 143
 144 /* Lookup a value for the variable named STR.
 145    First lookup in Scheme context (using the scm_lookup_cstr inferior
 146    function), then try lookup_symbol for compiled variables. */
 147
 148 static struct value *
 149 scm_lookup_name (char *str)
 150 {
 151   struct objfile *objf;
 152   struct gdbarch *gdbarch;
 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", &objf);
 160   gdbarch = get_objfile_arch (objf);
 161
 162   args[0] = value_allocate_space_in_inferior (len);
 163   args[1] = value_from_longest (builtin_type (gdbarch)->builtin_int, len);
 164   write_memory (value_as_long (args[0]), (gdb_byte *) str, len);
 165
 166   if (in_eval_c ()
 167       && (sym = lookup_symbol ("env",
 168                                expression_context_block,
 169                                VAR_DOMAIN, (int *) NULL)) != NULL)
 170     args[2] = value_of_variable (sym, expression_context_block);
 171   else
 172     /* FIXME in this case, we should try lookup_symbol first */
 173     args[2] = value_from_longest (builtin_type_scm, 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   write_memory (iaddr, (gdb_byte *) str, len);
 194   /* FIXME - should find and pass env */
 195   write_memory (iaddr + len, (gdb_byte *) "", 1);
 196   func = find_function_in_inferior ("scm_evstr", NULL);
 197   return call_function_by_hand (func, 1, &addr);
 198 }
 199
 200 static struct value *
 201 evaluate_exp (struct type *expect_type, struct expression *exp,
 202               int *pos, enum noside noside)
 203 {
 204   enum exp_opcode op = exp->elts[*pos].opcode;
 205   int len, pc;
 206   char *str;
 207   switch (op)
 208     {
 209     case OP_NAME:
 210       pc = (*pos)++;
 211       len = longest_to_int (exp->elts[pc + 1].longconst);
 212       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 213       if (noside == EVAL_SKIP)
 214         goto nosideret;
 215       str = &exp->elts[pc + 2].string;
 216       return scm_lookup_name (str);
 217     case OP_STRING:
 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_evaluate_string (str, len);
 225     default:;
 226     }
 227   return evaluate_subexp_standard (expect_type, exp, pos, noside);
 228 nosideret:
 229   return value_from_longest (builtin_type_int8, (LONGEST) 1);
 230 }
 231
 232 const struct exp_descriptor exp_descriptor_scm =
 233 {
 234   print_subexp_standard,
 235   operator_length_standard,
 236   op_name_standard,
 237   dump_subexp_body_standard,
 238   evaluate_exp
 239 };
 240
 241 const struct language_defn scm_language_defn =
 242 {
 243   "scheme",                     /* Language name */
 244   language_scm,
 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   c_print_type,                 /* Print a type using appropriate syntax */
 257   scm_val_print,                /* Print a value using appropriate syntax */
 258   scm_value_print,              /* Print a top-level value */
 259   NULL,                         /* Language specific skip_trampoline */
 260   NULL,                         /* name_of_this */
 261   basic_lookup_symbol_nonlocal, /* lookup_symbol_nonlocal */
 262   basic_lookup_transparent_type,/* lookup_transparent_type */
 263   NULL,                         /* Language specific symbol demangler */
 264   NULL,                         /* Language specific class_name_from_physname */
 265   NULL,                         /* expression operators for printing */
 266   1,                            /* c-style arrays */
 267   0,                            /* String lower bound */
 268   default_word_break_characters,
 269   default_make_symbol_completion_list,
 270   c_language_arch_info,
 271   default_print_array_index,
 272   default_pass_by_reference,
 273   LANG_MAGIC
 274 };
 275
 276 void
 277 _initialize_scheme_language (void)
 278 {
 279   add_language (&scm_language_defn);
 280   builtin_type_scm =
 281     init_type (TYPE_CODE_INT,
 282                gdbarch_long_bit (current_gdbarch) / TARGET_CHAR_BIT,
 283                0, "SCM", (struct objfile *) NULL);
 284 }