binutils-gdb/gdb/p-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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/* Pascal language support routines for GDB, the GNU debugger.
Copyright (C) 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/>. */
/* This file is derived from c-lang.c */
#include "defs.h"
#include "gdb_string.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "expression.h"
#include "parser-defs.h"
#include "language.h"
#include "p-lang.h"
#include "valprint.h"
#include "value.h"
#include <ctype.h>
extern void _initialize_pascal_language (void);
/* All GPC versions until now (2007-09-27) also define a symbol called
'_p_initialize'. Check for the presence of this symbol first. */
static const char GPC_P_INITIALIZE[] = "_p_initialize";
/* The name of the symbol that GPC uses as the name of the main
procedure (since version 20050212). */
static const char GPC_MAIN_PROGRAM_NAME_1[] = "_p__M0_main_program";
/* Older versions of GPC (versions older than 20050212) were using
a different name for the main procedure. */
static const char GPC_MAIN_PROGRAM_NAME_2[] = "pascal_main_program";
/* Function returning the special symbol name used
by GPC for the main procedure in the main program
if it is found in minimal symbol list.
This function tries to find minimal symbols generated by GPC
so that it finds the even if the program was compiled
without debugging information.
According to information supplied by Waldeck Hebisch,
this should work for all versions posterior to June 2000. */
const char *
pascal_main_name (void)
{
struct minimal_symbol *msym;
msym = lookup_minimal_symbol (GPC_P_INITIALIZE, NULL, NULL);
/* If '_p_initialize' was not found, the main program is likely not
written in Pascal. */
if (msym == NULL)
return NULL;
msym = lookup_minimal_symbol (GPC_MAIN_PROGRAM_NAME_1, NULL, NULL);
if (msym != NULL)
{
return GPC_MAIN_PROGRAM_NAME_1;
}
msym = lookup_minimal_symbol (GPC_MAIN_PROGRAM_NAME_2, NULL, NULL);
if (msym != NULL)
{
return GPC_MAIN_PROGRAM_NAME_2;
}
/* No known entry procedure found, the main program is probably
not compiled with GPC. */
return NULL;
}
/* Determines if type TYPE is a pascal string type.
Returns a positive value if the type is a known pascal string type.
This function is used by p-valprint.c code to allow better string display.
If it is a pascal string type, then it also sets info needed
to get the length and the data of the string
length_pos, length_size and string_pos are given in bytes.
char_size gives the element size in bytes.
FIXME: if the position or the size of these fields
are not multiple of TARGET_CHAR_BIT then the results are wrong
but this does not happen for Free Pascal nor for GPC. */
int
is_pascal_string_type (struct type *type,int *length_pos,
int *length_size, int *string_pos,
struct type **char_type,
const char **arrayname)
{
if (type != NULL && TYPE_CODE (type) == TYPE_CODE_STRUCT)
{
/* Old Borland type pascal strings from Free Pascal Compiler. */
/* Two fields: length and st. */
if (TYPE_NFIELDS (type) == 2
&& TYPE_FIELD_NAME (type, 0)
&& strcmp (TYPE_FIELD_NAME (type, 0), "length") == 0
&& TYPE_FIELD_NAME (type, 1)
&& strcmp (TYPE_FIELD_NAME (type, 1), "st") == 0)
{
if (length_pos)
*length_pos = TYPE_FIELD_BITPOS (type, 0) / TARGET_CHAR_BIT;
if (length_size)
*length_size = TYPE_LENGTH (TYPE_FIELD_TYPE (type, 0));
if (string_pos)
*string_pos = TYPE_FIELD_BITPOS (type, 1) / TARGET_CHAR_BIT;
if (char_type)
*char_type = TYPE_TARGET_TYPE (TYPE_FIELD_TYPE (type, 1));
if (arrayname)
*arrayname = TYPE_FIELD_NAME (type, 1);
return 2;
};
/* GNU pascal strings. */
/* Three fields: Capacity, length and schema$ or _p_schema. */
if (TYPE_NFIELDS (type) == 3
&& TYPE_FIELD_NAME (type, 0)
&& strcmp (TYPE_FIELD_NAME (type, 0), "Capacity") == 0
&& TYPE_FIELD_NAME (type, 1)
&& strcmp (TYPE_FIELD_NAME (type, 1), "length") == 0)
{
if (length_pos)
*length_pos = TYPE_FIELD_BITPOS (type, 1) / TARGET_CHAR_BIT;
if (length_size)
*length_size = TYPE_LENGTH (TYPE_FIELD_TYPE (type, 1));
if (string_pos)
*string_pos = TYPE_FIELD_BITPOS (type, 2) / TARGET_CHAR_BIT;
/* FIXME: how can I detect wide chars in GPC ?? */
if (char_type)
{
*char_type = TYPE_TARGET_TYPE (TYPE_FIELD_TYPE (type, 2));
if (TYPE_CODE (*char_type) == TYPE_CODE_ARRAY)
*char_type = TYPE_TARGET_TYPE (*char_type);
}
if (arrayname)
*arrayname = TYPE_FIELD_NAME (type, 2);
return 3;
};
}
return 0;
}
static void pascal_one_char (int, struct ui_file *, int *);
/* Print the character C on STREAM as part of the contents of a literal
string.
In_quotes is reset to 0 if a char is written with #4 notation. */
static void
pascal_one_char (int c, struct ui_file *stream, int *in_quotes)
{
if (c == '\'' || ((unsigned int) c <= 0xff && (PRINT_LITERAL_FORM (c))))
{
if (!(*in_quotes))
fputs_filtered ("'", stream);
*in_quotes = 1;
if (c == '\'')
{
fputs_filtered ("''", stream);
}
else
fprintf_filtered (stream, "%c", c);
}
else
{
if (*in_quotes)
fputs_filtered ("'", stream);
*in_quotes = 0;
fprintf_filtered (stream, "#%d", (unsigned int) c);
}
}
static void pascal_emit_char (int c, struct type *type,
struct ui_file *stream, int quoter);
/* 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. */
static void
pascal_emit_char (int c, struct type *type, struct ui_file *stream, int quoter)
{
int in_quotes = 0;
pascal_one_char (c, stream, &in_quotes);
if (in_quotes)
fputs_filtered ("'", stream);
}
void
pascal_printchar (int c, struct type *type, struct ui_file *stream)
{
int in_quotes = 0;
pascal_one_char (c, stream, &in_quotes);
if (in_quotes)
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. */
void
pascal_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)
{
enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
unsigned int i;
unsigned int things_printed = 0;
int in_quotes = 0;
int need_comma = 0;
int width;
/* Preserve TYPE's original type, just set its LENGTH. */
check_typedef (type);
width = TYPE_LENGTH (type);
/* If the string was not truncated due to `set print elements', and
the last byte of it is a null, we don't print that, in traditional C
style. */
if ((!force_ellipses) && length > 0
&& extract_unsigned_integer (string + (length - 1) * width, width,
byte_order) == 0)
length--;
if (length == 0)
{
fputs_filtered ("''", stream);
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;
unsigned long int current_char;
QUIT;
if (need_comma)
{
fputs_filtered (", ", stream);
need_comma = 0;
}
current_char = extract_unsigned_integer (string + i * width, width,
byte_order);
rep1 = i + 1;
reps = 1;
while (rep1 < length
&& extract_unsigned_integer (string + rep1 * width, width,
byte_order) == current_char)
{
++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;
}
pascal_printchar (current_char, 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) && (PRINT_LITERAL_FORM (current_char)))
{
if (options->inspect_it)
fputs_filtered ("\\'", stream);
else
fputs_filtered ("'", stream);
in_quotes = 1;
}
pascal_one_char (current_char, stream, &in_quotes);
++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);
}
/* Table mapping opcodes into strings for printing operators
and precedences of the operators. */
const struct op_print pascal_op_print_tab[] =
{
{",", BINOP_COMMA, PREC_COMMA, 0},
{":=", BINOP_ASSIGN, PREC_ASSIGN, 1},
{"or", BINOP_BITWISE_IOR, PREC_BITWISE_IOR, 0},
{"xor", BINOP_BITWISE_XOR, PREC_BITWISE_XOR, 0},
{"and", BINOP_BITWISE_AND, PREC_BITWISE_AND, 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},
{"shr", BINOP_RSH, PREC_SHIFT, 0},
{"shl", BINOP_LSH, PREC_SHIFT, 0},
{"+", BINOP_ADD, PREC_ADD, 0},
{"-", BINOP_SUB, PREC_ADD, 0},
{"*", BINOP_MUL, PREC_MUL, 0},
{"/", BINOP_DIV, PREC_MUL, 0},
{"div", BINOP_INTDIV, PREC_MUL, 0},
{"mod", BINOP_REM, PREC_MUL, 0},
{"@", BINOP_REPEAT, PREC_REPEAT, 0},
{"-", UNOP_NEG, PREC_PREFIX, 0},
{"not", UNOP_LOGICAL_NOT, PREC_PREFIX, 0},
{"^", UNOP_IND, PREC_SUFFIX, 1},
{"@", UNOP_ADDR, PREC_PREFIX, 0},
{"sizeof", UNOP_SIZEOF, PREC_PREFIX, 0},
{NULL, 0, 0, 0}
};
enum pascal_primitive_types {
pascal_primitive_type_int,
pascal_primitive_type_long,
pascal_primitive_type_short,
pascal_primitive_type_char,
pascal_primitive_type_float,
pascal_primitive_type_double,
pascal_primitive_type_void,
pascal_primitive_type_long_long,
pascal_primitive_type_signed_char,
pascal_primitive_type_unsigned_char,
pascal_primitive_type_unsigned_short,
pascal_primitive_type_unsigned_int,
pascal_primitive_type_unsigned_long,
pascal_primitive_type_unsigned_long_long,
pascal_primitive_type_long_double,
pascal_primitive_type_complex,
pascal_primitive_type_double_complex,
nr_pascal_primitive_types
};
static void
pascal_language_arch_info (struct gdbarch *gdbarch,
struct language_arch_info *lai)
{
const struct builtin_type *builtin = builtin_type (gdbarch);
lai->string_char_type = builtin->builtin_char;
lai->primitive_type_vector
= GDBARCH_OBSTACK_CALLOC (gdbarch, nr_pascal_primitive_types + 1,
struct type *);
lai->primitive_type_vector [pascal_primitive_type_int]
= builtin->builtin_int;
lai->primitive_type_vector [pascal_primitive_type_long]
= builtin->builtin_long;
lai->primitive_type_vector [pascal_primitive_type_short]
= builtin->builtin_short;
lai->primitive_type_vector [pascal_primitive_type_char]
= builtin->builtin_char;
lai->primitive_type_vector [pascal_primitive_type_float]
= builtin->builtin_float;
lai->primitive_type_vector [pascal_primitive_type_double]
= builtin->builtin_double;
lai->primitive_type_vector [pascal_primitive_type_void]
= builtin->builtin_void;
lai->primitive_type_vector [pascal_primitive_type_long_long]
= builtin->builtin_long_long;
lai->primitive_type_vector [pascal_primitive_type_signed_char]
= builtin->builtin_signed_char;
lai->primitive_type_vector [pascal_primitive_type_unsigned_char]
= builtin->builtin_unsigned_char;
lai->primitive_type_vector [pascal_primitive_type_unsigned_short]
= builtin->builtin_unsigned_short;
lai->primitive_type_vector [pascal_primitive_type_unsigned_int]
= builtin->builtin_unsigned_int;
lai->primitive_type_vector [pascal_primitive_type_unsigned_long]
= builtin->builtin_unsigned_long;
lai->primitive_type_vector [pascal_primitive_type_unsigned_long_long]
= builtin->builtin_unsigned_long_long;
lai->primitive_type_vector [pascal_primitive_type_long_double]
= builtin->builtin_long_double;
lai->primitive_type_vector [pascal_primitive_type_complex]
= builtin->builtin_complex;
lai->primitive_type_vector [pascal_primitive_type_double_complex]
= builtin->builtin_double_complex;
lai->bool_type_symbol = "boolean";
lai->bool_type_default = builtin->builtin_bool;
}
const struct language_defn pascal_language_defn =
{
"pascal", /* Language name */
language_pascal,
range_check_on,
type_check_on,
case_sensitive_on,
array_row_major,
macro_expansion_no,
&exp_descriptor_standard,
pascal_parse,
pascal_error,
null_post_parser,
pascal_printchar, /* Print a character constant */
pascal_printstr, /* Function to print string constant */
pascal_emit_char, /* Print a single char */
pascal_print_type, /* Print a type using appropriate syntax */
pascal_print_typedef, /* Print a typedef using appropriate syntax */
pascal_val_print, /* Print a value using appropriate syntax */
pascal_value_print, /* Print a top-level value */
default_read_var_value, /* la_read_var_value */
NULL, /* Language specific skip_trampoline */
"this", /* 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 */
pascal_op_print_tab, /* expression operators for printing */
1, /* c-style arrays */
0, /* String lower bound */
default_word_break_characters,
default_make_symbol_completion_list,
pascal_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
};
void
_initialize_pascal_language (void)
{
add_language (&pascal_language_defn);
}