darling-gdb/gdb/m2-lang.c
Joel Brobecker a5ee536be2 language-specific read_var_value for Ada renamings
The purpose of this patch is to better support renamings in the
"info locals" command. Consider ...

    procedure Foo is
       GV : Integer renames Pck.Global_Variable;
    begin
       Increment (GV); -- STOP
    end Foo;

... Pck.Global_Variable is just an integer. After having stopped at
the "STOP" line, "info locals" yields:

    (gdb) info locals
    gv = <error reading variable gv (Cannot access memory at address 0xffffffffffffffff)>

In reality, two things are happening:

   (1) Variable "GV" does not exist, which is normal, since there is
       "GV" the renaming of another variable;

   (2) But to allow the user access to that renaming the same way
       the code has, the compiler produces an artificial variable
       whose name encodes the renaming:

        gv___XR_pck__global_variable___XE

       For practical reasons, the artificial variable itself is given
       irrelevant types and addresses.

But the "info locals" command does not act as if it was a short-cut
of "foreach VAR in locals, print VAR". Instead it gets the value of
each VAR directly, which does not work in this case, since the variable
is artificial and needs to be decoded first.

This patch makes the "read_var_value" routine language-specific.
The old implementation of "read_var_value" gets renamed to
"default_read_var_value" and all languages now use it (unchanged
behavior), except for Ada. In Ada, the new function ada_read_var_value
checks if we have a renaming, and if so, evaluates its value, or else
defers to default_read_var_value.

gdb/ChangeLog:

        * language.h (struct language_defn): New "method" la_read_var_value.
        * findvar.c: #include "language.h".
        (default_read_var_value): Renames read_var_value.  Rewrite
        function description.
        (read_var_value): New function.
        * value.h (default_read_var_value): Add prototype.
        * ada-lang.c (ada_read_renaming_var_value, ada_read_var_value):
        New functions.
        (ada_language_defn): Add entry for la_read_var_value.
        * c-lang.c, d-lang.c, f-lang.c, jv-lang.c, language.c,
        * m2-lang.c, objc-lang.c, opencl-lang.c, p-lang.c: Update
        language_defn structures to add entry for new la_read_var_value
        field.
2012-03-02 19:29:01 +00:00

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/* Modula 2 language support routines for GDB, the GNU debugger.
Copyright (C) 1992-1996, 1998, 2000, 2002-2005, 2007-2012 Free
Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "expression.h"
#include "parser-defs.h"
#include "language.h"
#include "m2-lang.h"
#include "c-lang.h"
#include "valprint.h"
extern void _initialize_m2_language (void);
static void m2_printchar (int, struct type *, struct ui_file *);
static void m2_emit_char (int, struct type *, struct ui_file *, int);
/* Print the character C on STREAM as part of the contents of a literal
string whose delimiter is QUOTER. Note that that format for printing
characters and strings is language specific.
FIXME: This is a copy of the same function from c-exp.y. It should
be replaced with a true Modula version. */
static void
m2_emit_char (int c, struct type *type, struct ui_file *stream, int quoter)
{
c &= 0xFF; /* Avoid sign bit follies. */
if (PRINT_LITERAL_FORM (c))
{
if (c == '\\' || c == quoter)
{
fputs_filtered ("\\", stream);
}
fprintf_filtered (stream, "%c", c);
}
else
{
switch (c)
{
case '\n':
fputs_filtered ("\\n", stream);
break;
case '\b':
fputs_filtered ("\\b", stream);
break;
case '\t':
fputs_filtered ("\\t", stream);
break;
case '\f':
fputs_filtered ("\\f", stream);
break;
case '\r':
fputs_filtered ("\\r", stream);
break;
case '\033':
fputs_filtered ("\\e", stream);
break;
case '\007':
fputs_filtered ("\\a", stream);
break;
default:
fprintf_filtered (stream, "\\%.3o", (unsigned int) c);
break;
}
}
}
/* FIXME: This is a copy of the same function from c-exp.y. It should
be replaced with a true Modula version. */
static void
m2_printchar (int c, struct type *type, struct ui_file *stream)
{
fputs_filtered ("'", stream);
LA_EMIT_CHAR (c, type, stream, '\'');
fputs_filtered ("'", stream);
}
/* Print the character string STRING, printing at most LENGTH characters.
Printing stops early if the number hits print_max; repeat counts
are printed as appropriate. Print ellipses at the end if we
had to stop before printing LENGTH characters, or if FORCE_ELLIPSES.
FIXME: This is a copy of the same function from c-exp.y. It should
be replaced with a true Modula version. */
static void
m2_printstr (struct ui_file *stream, struct type *type, const gdb_byte *string,
unsigned int length, const char *encoding, int force_ellipses,
const struct value_print_options *options)
{
unsigned int i;
unsigned int things_printed = 0;
int in_quotes = 0;
int need_comma = 0;
if (length == 0)
{
fputs_filtered ("\"\"", gdb_stdout);
return;
}
for (i = 0; i < length && things_printed < options->print_max; ++i)
{
/* Position of the character we are examining
to see whether it is repeated. */
unsigned int rep1;
/* Number of repetitions we have detected so far. */
unsigned int reps;
QUIT;
if (need_comma)
{
fputs_filtered (", ", stream);
need_comma = 0;
}
rep1 = i + 1;
reps = 1;
while (rep1 < length && string[rep1] == string[i])
{
++rep1;
++reps;
}
if (reps > options->repeat_count_threshold)
{
if (in_quotes)
{
if (options->inspect_it)
fputs_filtered ("\\\", ", stream);
else
fputs_filtered ("\", ", stream);
in_quotes = 0;
}
m2_printchar (string[i], type, stream);
fprintf_filtered (stream, " <repeats %u times>", reps);
i = rep1 - 1;
things_printed += options->repeat_count_threshold;
need_comma = 1;
}
else
{
if (!in_quotes)
{
if (options->inspect_it)
fputs_filtered ("\\\"", stream);
else
fputs_filtered ("\"", stream);
in_quotes = 1;
}
LA_EMIT_CHAR (string[i], type, stream, '"');
++things_printed;
}
}
/* Terminate the quotes if necessary. */
if (in_quotes)
{
if (options->inspect_it)
fputs_filtered ("\\\"", stream);
else
fputs_filtered ("\"", stream);
}
if (force_ellipses || i < length)
fputs_filtered ("...", stream);
}
static struct value *
evaluate_subexp_modula2 (struct type *expect_type, struct expression *exp,
int *pos, enum noside noside)
{
enum exp_opcode op = exp->elts[*pos].opcode;
struct value *arg1;
struct value *arg2;
struct type *type;
switch (op)
{
case UNOP_HIGH:
(*pos)++;
arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
return arg1;
else
{
arg1 = coerce_ref (arg1);
type = check_typedef (value_type (arg1));
if (m2_is_unbounded_array (type))
{
struct value *temp = arg1;
type = TYPE_FIELD_TYPE (type, 1);
/* i18n: Do not translate the "_m2_high" part! */
arg1 = value_struct_elt (&temp, NULL, "_m2_high", NULL,
_("unbounded structure "
"missing _m2_high field"));
if (value_type (arg1) != type)
arg1 = value_cast (type, arg1);
}
}
return arg1;
case BINOP_SUBSCRIPT:
(*pos)++;
arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
if (noside == EVAL_SKIP)
goto nosideret;
/* If the user attempts to subscript something that is not an
array or pointer type (like a plain int variable for example),
then report this as an error. */
arg1 = coerce_ref (arg1);
type = check_typedef (value_type (arg1));
if (m2_is_unbounded_array (type))
{
struct value *temp = arg1;
type = TYPE_FIELD_TYPE (type, 0);
if (type == NULL || (TYPE_CODE (type) != TYPE_CODE_PTR))
{
warning (_("internal error: unbounded "
"array structure is unknown"));
return evaluate_subexp_standard (expect_type, exp, pos, noside);
}
/* i18n: Do not translate the "_m2_contents" part! */
arg1 = value_struct_elt (&temp, NULL, "_m2_contents", NULL,
_("unbounded structure "
"missing _m2_contents field"));
if (value_type (arg1) != type)
arg1 = value_cast (type, arg1);
check_typedef (value_type (arg1));
return value_ind (value_ptradd (arg1, value_as_long (arg2)));
}
else
if (TYPE_CODE (type) != TYPE_CODE_ARRAY)
{
if (TYPE_NAME (type))
error (_("cannot subscript something of type `%s'"),
TYPE_NAME (type));
else
error (_("cannot subscript requested type"));
}
if (noside == EVAL_AVOID_SIDE_EFFECTS)
return value_zero (TYPE_TARGET_TYPE (type), VALUE_LVAL (arg1));
else
return value_subscript (arg1, value_as_long (arg2));
default:
return evaluate_subexp_standard (expect_type, exp, pos, noside);
}
nosideret:
return value_from_longest (builtin_type (exp->gdbarch)->builtin_int, 1);
}
/* Table of operators and their precedences for printing expressions. */
static const struct op_print m2_op_print_tab[] =
{
{"+", BINOP_ADD, PREC_ADD, 0},
{"+", UNOP_PLUS, PREC_PREFIX, 0},
{"-", BINOP_SUB, PREC_ADD, 0},
{"-", UNOP_NEG, PREC_PREFIX, 0},
{"*", BINOP_MUL, PREC_MUL, 0},
{"/", BINOP_DIV, PREC_MUL, 0},
{"DIV", BINOP_INTDIV, PREC_MUL, 0},
{"MOD", BINOP_REM, PREC_MUL, 0},
{":=", BINOP_ASSIGN, PREC_ASSIGN, 1},
{"OR", BINOP_LOGICAL_OR, PREC_LOGICAL_OR, 0},
{"AND", BINOP_LOGICAL_AND, PREC_LOGICAL_AND, 0},
{"NOT", UNOP_LOGICAL_NOT, PREC_PREFIX, 0},
{"=", BINOP_EQUAL, PREC_EQUAL, 0},
{"<>", BINOP_NOTEQUAL, PREC_EQUAL, 0},
{"<=", BINOP_LEQ, PREC_ORDER, 0},
{">=", BINOP_GEQ, PREC_ORDER, 0},
{">", BINOP_GTR, PREC_ORDER, 0},
{"<", BINOP_LESS, PREC_ORDER, 0},
{"^", UNOP_IND, PREC_PREFIX, 0},
{"@", BINOP_REPEAT, PREC_REPEAT, 0},
{"CAP", UNOP_CAP, PREC_BUILTIN_FUNCTION, 0},
{"CHR", UNOP_CHR, PREC_BUILTIN_FUNCTION, 0},
{"ORD", UNOP_ORD, PREC_BUILTIN_FUNCTION, 0},
{"FLOAT", UNOP_FLOAT, PREC_BUILTIN_FUNCTION, 0},
{"HIGH", UNOP_HIGH, PREC_BUILTIN_FUNCTION, 0},
{"MAX", UNOP_MAX, PREC_BUILTIN_FUNCTION, 0},
{"MIN", UNOP_MIN, PREC_BUILTIN_FUNCTION, 0},
{"ODD", UNOP_ODD, PREC_BUILTIN_FUNCTION, 0},
{"TRUNC", UNOP_TRUNC, PREC_BUILTIN_FUNCTION, 0},
{NULL, 0, 0, 0}
};
/* The built-in types of Modula-2. */
enum m2_primitive_types {
m2_primitive_type_char,
m2_primitive_type_int,
m2_primitive_type_card,
m2_primitive_type_real,
m2_primitive_type_bool,
nr_m2_primitive_types
};
static void
m2_language_arch_info (struct gdbarch *gdbarch,
struct language_arch_info *lai)
{
const struct builtin_m2_type *builtin = builtin_m2_type (gdbarch);
lai->string_char_type = builtin->builtin_char;
lai->primitive_type_vector
= GDBARCH_OBSTACK_CALLOC (gdbarch, nr_m2_primitive_types + 1,
struct type *);
lai->primitive_type_vector [m2_primitive_type_char]
= builtin->builtin_char;
lai->primitive_type_vector [m2_primitive_type_int]
= builtin->builtin_int;
lai->primitive_type_vector [m2_primitive_type_card]
= builtin->builtin_card;
lai->primitive_type_vector [m2_primitive_type_real]
= builtin->builtin_real;
lai->primitive_type_vector [m2_primitive_type_bool]
= builtin->builtin_bool;
lai->bool_type_symbol = "BOOLEAN";
lai->bool_type_default = builtin->builtin_bool;
}
const struct exp_descriptor exp_descriptor_modula2 =
{
print_subexp_standard,
operator_length_standard,
operator_check_standard,
op_name_standard,
dump_subexp_body_standard,
evaluate_subexp_modula2
};
const struct language_defn m2_language_defn =
{
"modula-2",
language_m2,
range_check_on,
type_check_on,
case_sensitive_on,
array_row_major,
macro_expansion_no,
&exp_descriptor_modula2,
m2_parse, /* parser */
m2_error, /* parser error function */
null_post_parser,
m2_printchar, /* Print character constant */
m2_printstr, /* function to print string constant */
m2_emit_char, /* Function to print a single character */
m2_print_type, /* Print a type using appropriate syntax */
m2_print_typedef, /* Print a typedef using appropriate syntax */
m2_val_print, /* Print a value using appropriate syntax */
c_value_print, /* Print a top-level value */
default_read_var_value, /* la_read_var_value */
NULL, /* Language specific skip_trampoline */
NULL, /* name_of_this */
basic_lookup_symbol_nonlocal, /* lookup_symbol_nonlocal */
basic_lookup_transparent_type,/* lookup_transparent_type */
NULL, /* Language specific symbol demangler */
NULL, /* Language specific
class_name_from_physname */
m2_op_print_tab, /* expression operators for printing */
0, /* arrays are first-class (not c-style) */
0, /* String lower bound */
default_word_break_characters,
default_make_symbol_completion_list,
m2_language_arch_info,
default_print_array_index,
default_pass_by_reference,
default_get_string,
NULL, /* la_get_symbol_name_cmp */
iterate_over_symbols,
LANG_MAGIC
};
static void *
build_m2_types (struct gdbarch *gdbarch)
{
struct builtin_m2_type *builtin_m2_type
= GDBARCH_OBSTACK_ZALLOC (gdbarch, struct builtin_m2_type);
/* Modula-2 "pervasive" types. NOTE: these can be redefined!!! */
builtin_m2_type->builtin_int
= arch_integer_type (gdbarch, gdbarch_int_bit (gdbarch), 0, "INTEGER");
builtin_m2_type->builtin_card
= arch_integer_type (gdbarch, gdbarch_int_bit (gdbarch), 1, "CARDINAL");
builtin_m2_type->builtin_real
= arch_float_type (gdbarch, gdbarch_float_bit (gdbarch), "REAL", NULL);
builtin_m2_type->builtin_char
= arch_character_type (gdbarch, TARGET_CHAR_BIT, 1, "CHAR");
builtin_m2_type->builtin_bool
= arch_boolean_type (gdbarch, gdbarch_int_bit (gdbarch), 1, "BOOLEAN");
return builtin_m2_type;
}
static struct gdbarch_data *m2_type_data;
const struct builtin_m2_type *
builtin_m2_type (struct gdbarch *gdbarch)
{
return gdbarch_data (gdbarch, m2_type_data);
}
/* Initialization for Modula-2 */
void
_initialize_m2_language (void)
{
m2_type_data = gdbarch_data_register_post_init (build_m2_types);
add_language (&m2_language_defn);
}