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 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., 51 Franklin Street, Fifth Floor,
  21    Boston, MA 02110-1301, 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_NAME (type) && strcmp (TYPE_NAME (type), "SCM") == 0)
  63     {
  64       return 1;
  65     }
  66   return 0;
  67 }
  68
  69 /* Get the INDEX'th SCM value, assuming SVALUE is the address
  70    of the 0'th one.  */
  71
  72 LONGEST
  73 scm_get_field (LONGEST svalue, int index)
  74 {
  75   gdb_byte buffer[20];
  76   read_memory (SCM2PTR (svalue) + index * TYPE_LENGTH (builtin_type_scm),
  77                buffer, TYPE_LENGTH (builtin_type_scm));
  78   return extract_signed_integer (buffer, TYPE_LENGTH (builtin_type_scm));
  79 }
  80
  81 /* Unpack a value of type TYPE in buffer VALADDR as an integer
  82    (if CONTEXT == TYPE_CODE_IN), a pointer (CONTEXT == TYPE_CODE_PTR),
  83    or Boolean (CONTEXT == TYPE_CODE_BOOL).  */
  84
  85 LONGEST
  86 scm_unpack (struct type *type, const gdb_byte *valaddr, enum type_code context)
  87 {
  88   if (is_scmvalue_type (type))
  89     {
  90       LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));
  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       if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)
 140         return 1;
 141     }
 142   return 0;
 143 }
 144
 145 /* Lookup a value for the variable named STR.
 146    First lookup in Scheme context (using the scm_lookup_cstr inferior
 147    function), then try lookup_symbol for compiled variables. */
 148
 149 static struct value *
 150 scm_lookup_name (char *str)
 151 {
 152   struct value *args[3];
 153   int len = strlen (str);
 154   struct value *func;
 155   struct value *val;
 156   struct symbol *sym;
 157   args[0] = value_allocate_space_in_inferior (len);
 158   args[1] = value_from_longest (builtin_type_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,
 165                                (struct symtab **) NULL)) != NULL)
 166     args[2] = value_of_variable (sym, expression_context_block);
 167   else
 168     /* FIXME in this case, we should try lookup_symbol first */
 169     args[2] = value_from_longest (builtin_type_scm, SCM_EOL);
 170
 171   func = find_function_in_inferior ("scm_lookup_cstr");
 172   val = call_function_by_hand (func, 3, args);
 173   if (!value_logical_not (val))
 174     return value_ind (val);
 175
 176   sym = lookup_symbol (str,
 177                        expression_context_block,
 178                        VAR_DOMAIN, (int *) NULL,
 179                        (struct symtab **) NULL);
 180   if (sym)
 181     return value_of_variable (sym, NULL);
 182   error (_("No symbol \"%s\" in current context."), str);
 183 }
 184
 185 struct value *
 186 scm_evaluate_string (char *str, int len)
 187 {
 188   struct value *func;
 189   struct value *addr = value_allocate_space_in_inferior (len + 1);
 190   LONGEST iaddr = value_as_long (addr);
 191   write_memory (iaddr, (gdb_byte *) str, len);
 192   /* FIXME - should find and pass env */
 193   write_memory (iaddr + len, (gdb_byte *) "", 1);
 194   func = find_function_in_inferior ("scm_evstr");
 195   return call_function_by_hand (func, 1, &addr);
 196 }
 197
 198 static struct value *
 199 evaluate_exp (struct type *expect_type, struct expression *exp,
 200               int *pos, enum noside noside)
 201 {
 202   enum exp_opcode op = exp->elts[*pos].opcode;
 203   int len, pc;
 204   char *str;
 205   switch (op)
 206     {
 207     case OP_NAME:
 208       pc = (*pos)++;
 209       len = longest_to_int (exp->elts[pc + 1].longconst);
 210       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 211       if (noside == EVAL_SKIP)
 212         goto nosideret;
 213       str = &exp->elts[pc + 2].string;
 214       return scm_lookup_name (str);
 215     case OP_STRING:
 216       pc = (*pos)++;
 217       len = longest_to_int (exp->elts[pc + 1].longconst);
 218       (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
 219       if (noside == EVAL_SKIP)
 220         goto nosideret;
 221       str = &exp->elts[pc + 2].string;
 222       return scm_evaluate_string (str, len);
 223     default:;
 224     }
 225   return evaluate_subexp_standard (expect_type, exp, pos, noside);
 226 nosideret:
 227   return value_from_longest (builtin_type_long, (LONGEST) 1);
 228 }
 229
 230 const struct exp_descriptor exp_descriptor_scm =
 231 {
 232   print_subexp_standard,
 233   operator_length_standard,
 234   op_name_standard,
 235   dump_subexp_body_standard,
 236   evaluate_exp
 237 };
 238
 239 const struct language_defn scm_language_defn =
 240 {
 241   "scheme",                     /* Language name */
 242   language_scm,
 243   NULL,
 244   range_check_off,
 245   type_check_off,
 246   case_sensitive_off,
 247   array_row_major,
 248   &exp_descriptor_scm,
 249   scm_parse,
 250   c_error,
 251   null_post_parser,
 252   scm_printchar,                /* Print a character constant */
 253   scm_printstr,                 /* Function to print string constant */
 254   NULL,                         /* Function to print a single character */
 255   NULL,                         /* Create fundamental type in this language */
 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   value_of_this,                /* value_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   NULL,
 269   default_word_break_characters,
 270   c_language_arch_info,
 271   default_print_array_index,
 272   LANG_MAGIC
 273 };
 274
 275 void
 276 _initialize_scheme_language (void)
 277 {
 278   add_language (&scm_language_defn);
 279   builtin_type_scm =
 280     init_type (TYPE_CODE_INT,
 281                gdbarch_long_bit (current_gdbarch) / TARGET_CHAR_BIT,
 282                0, "SCM", (struct objfile *) NULL);
 283 }