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binutils-gdb/gdb/cp-valprint.c
Andrew Burgess 2e62ab400f gdb: Introduce 'print max-depth' feature 
Introduce a new print setting max-depth which can be set with 'set
print max-depth DEPTH'.  The default value of DEPTH is 20, but this
can also be set to unlimited.

When GDB is printing a value containing nested structures GDB will
stop descending at depth DEPTH.  Here is a small example:

    typedef struct s1 { int a; } s1;
    typedef struct s2 { s1 b; } s2;
    typedef struct s3 { s2 c; } s3;
    typedef struct s4 { s3 d; } s4;

    s4 var = { { { { 3 } } } };

The following table shows how various depth settings affect printing
of 'var':

    | Depth Setting | Result of 'p var'              |
    |---------------+--------------------------------|
    |     Unlimited | $1 = {d = {c = {b = {a = 3}}}} |
    |             4 | $1 = {d = {c = {b = {a = 3}}}} |
    |             3 | $1 = {d = {c = {b = {...}}}}   |
    |             2 | $1 = {d = {c = {...}}}         |
    |             1 | $1 = {d = {...}}               |
    |             0 | $1 = {...}                     |

Only structures, unions, and arrays are replaced in this way, scalars
and strings are not replaced.

The replacement is counted from the level at which you print, not from
the top level of the structure.  So, consider the above example and
this GDB session:

    (gdb) set print max-depth 2
    (gdb) p var
    $1 = {d = {c = {...}}}
    (gdb) p var.d
    $2 = {c = {b = {...}}}
    (gdb) p var.d.c
    $3 = {b = {a = 3}}

Setting the max-depth to 2 doesn't prevent the user from exploring
deeper into 'var' by asking for specific sub-fields to be printed.

The motivation behind this feature is to try and give the user more
control over how much is printed when examining large, complex data
structures.

The default max-depth of 20 means that there is a change in GDB's
default behaviour.  Someone printing a data structure with 20 levels
of nesting will now see '{...}' instead of their data, they would need
to adjust the max depth, or call print again naming a specific field
in order to dig deeper into their data structure.  If this is
considered a problem then we could increase the default, or even make
the default unlimited.

This commit relies on the previous commit, which added a new field to
the language structure, this new field was a string that contained the
pattern that should be used when a structure/union/array is replaced
in the output, this allows languages to use a syntax that is more
appropriate, mostly this will be selecting the correct types of
bracket '(...)' or '{...}', both of which are currently in use.

This commit should have no impact on MI output, expressions are
printed through the MI using -var-create and then -var-list-children.
As each use of -var-list-children only ever displays a single level of
an expression then the max-depth setting will have no impact.

This commit also adds the max-depth mechanism to the scripting
language pretty printers following basically the same rules as for the
built in value printing.

One quirk is that when printing a value using the display hint 'map',
if the keys of the map are structs then GDB will hide the keys one
depth level after it hides the values, this ensures that GDB produces
output like this:

  $1 = map_object = {[{key1}] = {...}, [{key2}] = {...}}

Instead of this less helpful output:

  $1 = map_object = {[{...}] = {...}, [{...}] = {...}}

This is covered by the new tests in gdb.python/py-nested-maps.exp.

gdb/ChangeLog:

	* cp-valprint.c (cp_print_value_fields): Allow an additional level
	of depth when printing anonymous structs or unions.
	* guile/scm-pretty-print.c (gdbscm_apply_val_pretty_printer):
	Don't print either the top-level value, or the children if the
	max-depth is exceeded.
	(ppscm_print_children): When printing the key of a map, allow one
	extra level of depth.
	* python/py-prettyprint.c (gdbpy_apply_val_pretty_printer): Don't
	print either the top-level value, or the children if the max-depth
	is exceeded.
	(print_children): When printing the key of a map, allow one extra
	level of depth.
	* python/py-value.c (valpy_format_string): Add max_depth keyword.
	* valprint.c: (PRINT_MAX_DEPTH_DEFAULT): Define.
	(user_print_options): Initialise max_depth field.
	(val_print_scalar_or_string_type_p): New function.
	(val_print): Check to see if the max depth has been reached.
	(val_print_check_max_depth): Define new function.
	(show_print_max_depth): New function.
	(_initialize_valprint): Add 'print max-depth' option.
	* valprint.h (struct value_print_options) <max_depth>: New field.
	(val_print_check_max_depth): Declare new function.
	* NEWS: Document new feature.

gdb/doc/ChangeLog:

	* gdb.texinfo (Print Settings): Document 'print max-depth'.
	* guile.texi (Guile Pretty Printing API): Document that 'print
	max-depth' can effect the display of a values children.
	* python.texi (Pretty Printing API): Likewise.
	(Values From Inferior): Document max_depth keyword.

gdb/testsuite/ChangeLog:

	* gdb.base/max-depth.c: New file.
	* gdb.base/max-depth.exp: New file.
	* gdb.python/py-nested-maps.c: New file.
	* gdb.python/py-nested-maps.exp: New file.
	* gdb.python/py-nested-maps.py: New file.
	* gdb.python/py-format-string.exp (test_max_depth): New proc.
	(test_all_common): Call test_max_depth.
	* gdb.fortran/max-depth.exp: New file.
	* gdb.fortran/max-depth.f90: New file.
	* gdb.go/max-depth.exp: New file.
	* gdb.go/max-depth.go: New file.
	* gdb.modula2/max-depth.exp: New file.
	* gdb.modula2/max-depth.c: New file.
	* lib/gdb.exp (get_print_expr_at_depths): New proc.
2019-04-29 22:01:09 +01:00

857 lines
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/* Support for printing C++ values for GDB, the GNU debugger.
Copyright (C) 1986-2019 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 "gdb_obstack.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "expression.h"
#include "value.h"
#include "command.h"
#include "gdbcmd.h"
#include "demangle.h"
#include "annotate.h"
#include "c-lang.h"
#include "target.h"
#include "cp-abi.h"
#include "valprint.h"
#include "cp-support.h"
#include "language.h"
#include "extension.h"
#include "typeprint.h"
#include "common/byte-vector.h"
/* Controls printing of vtbl's. */
static void
show_vtblprint (struct ui_file *file, int from_tty,
struct cmd_list_element *c, const char *value)
{
fprintf_filtered (file, _("\
Printing of C++ virtual function tables is %s.\n"),
value);
}
/* Controls looking up an object's derived type using what we find in
its vtables. */
static void
show_objectprint (struct ui_file *file, int from_tty,
struct cmd_list_element *c,
const char *value)
{
fprintf_filtered (file, _("\
Printing of object's derived type based on vtable info is %s.\n"),
value);
}
static void
show_static_field_print (struct ui_file *file, int from_tty,
struct cmd_list_element *c,
const char *value)
{
fprintf_filtered (file,
_("Printing of C++ static members is %s.\n"),
value);
}
static struct obstack dont_print_vb_obstack;
static struct obstack dont_print_statmem_obstack;
static struct obstack dont_print_stat_array_obstack;
static void cp_print_static_field (struct type *, struct value *,
struct ui_file *, int,
const struct value_print_options *);
static void cp_print_value (struct type *, struct type *,
LONGEST,
CORE_ADDR, struct ui_file *,
int, struct value *,
const struct value_print_options *,
struct type **);
/* GCC versions after 2.4.5 use this. */
extern const char vtbl_ptr_name[] = "__vtbl_ptr_type";
/* Return truth value for assertion that TYPE is of the type
"pointer to virtual function". */
int
cp_is_vtbl_ptr_type (struct type *type)
{
const char *type_name = TYPE_NAME (type);
return (type_name != NULL && !strcmp (type_name, vtbl_ptr_name));
}
/* Return truth value for the assertion that TYPE is of the type
"pointer to virtual function table". */
int
cp_is_vtbl_member (struct type *type)
{
/* With older versions of g++, the vtbl field pointed to an array of
structures. Nowadays it points directly to the structure. */
if (TYPE_CODE (type) == TYPE_CODE_PTR)
{
type = TYPE_TARGET_TYPE (type);
if (TYPE_CODE (type) == TYPE_CODE_ARRAY)
{
type = TYPE_TARGET_TYPE (type);
if (TYPE_CODE (type) == TYPE_CODE_STRUCT /* if not using thunks */
|| TYPE_CODE (type) == TYPE_CODE_PTR) /* if using thunks */
{
/* Virtual functions tables are full of pointers
to virtual functions. */
return cp_is_vtbl_ptr_type (type);
}
}
else if (TYPE_CODE (type) == TYPE_CODE_STRUCT) /* if not using thunks */
{
return cp_is_vtbl_ptr_type (type);
}
else if (TYPE_CODE (type) == TYPE_CODE_PTR) /* if using thunks */
{
/* The type name of the thunk pointer is NULL when using
dwarf2. We could test for a pointer to a function, but
there is no type info for the virtual table either, so it
wont help. */
return cp_is_vtbl_ptr_type (type);
}
}
return 0;
}
/* Mutually recursive subroutines of cp_print_value and c_val_print to
print out a structure's fields: cp_print_value_fields and
cp_print_value.
TYPE, VALADDR, ADDRESS, STREAM, RECURSE, and OPTIONS have the same
meanings as in cp_print_value and c_val_print.
2nd argument REAL_TYPE is used to carry over the type of the
derived class across the recursion to base classes.
DONT_PRINT is an array of baseclass types that we should not print,
or zero if called from top level. */
void
cp_print_value_fields (struct type *type, struct type *real_type,
LONGEST offset,
CORE_ADDR address, struct ui_file *stream,
int recurse, struct value *val,
const struct value_print_options *options,
struct type **dont_print_vb,
int dont_print_statmem)
{
int i, len, n_baseclasses;
int fields_seen = 0;
static int last_set_recurse = -1;
type = check_typedef (type);
if (recurse == 0)
{
/* Any object can be left on obstacks only during an unexpected
error. */
if (obstack_object_size (&dont_print_statmem_obstack) > 0)
{
obstack_free (&dont_print_statmem_obstack, NULL);
obstack_begin (&dont_print_statmem_obstack,
32 * sizeof (CORE_ADDR));
}
if (obstack_object_size (&dont_print_stat_array_obstack) > 0)
{
obstack_free (&dont_print_stat_array_obstack, NULL);
obstack_begin (&dont_print_stat_array_obstack,
32 * sizeof (struct type *));
}
}
fprintf_filtered (stream, "{");
len = TYPE_NFIELDS (type);
n_baseclasses = TYPE_N_BASECLASSES (type);
/* First, print out baseclasses such that we don't print
duplicates of virtual baseclasses. */
if (n_baseclasses > 0)
cp_print_value (type, real_type,
offset, address, stream,
recurse + 1, val, options,
dont_print_vb);
/* Second, print out data fields */
/* If there are no data fields, skip this part */
if (len == n_baseclasses || !len)
fprintf_filtered (stream, "<No data fields>");
else
{
size_t statmem_obstack_initial_size = 0;
size_t stat_array_obstack_initial_size = 0;
struct type *vptr_basetype = NULL;
int vptr_fieldno;
if (dont_print_statmem == 0)
{
statmem_obstack_initial_size =
obstack_object_size (&dont_print_statmem_obstack);
if (last_set_recurse != recurse)
{
stat_array_obstack_initial_size =
obstack_object_size (&dont_print_stat_array_obstack);
last_set_recurse = recurse;
}
}
vptr_fieldno = get_vptr_fieldno (type, &vptr_basetype);
for (i = n_baseclasses; i < len; i++)
{
const gdb_byte *valaddr = value_contents_for_printing (val);
/* If requested, skip printing of static fields. */
if (!options->static_field_print
&& field_is_static (&TYPE_FIELD (type, i)))
continue;
if (fields_seen)
{
fputs_filtered (",", stream);
if (!options->prettyformat)
fputs_filtered (" ", stream);
}
else if (n_baseclasses > 0)
{
if (options->prettyformat)
{
fprintf_filtered (stream, "\n");
print_spaces_filtered (2 + 2 * recurse, stream);
fputs_filtered ("members of ", stream);
fputs_filtered (TYPE_NAME (type), stream);
fputs_filtered (":", stream);
}
}
fields_seen = 1;
if (options->prettyformat)
{
fprintf_filtered (stream, "\n");
print_spaces_filtered (2 + 2 * recurse, stream);
}
else
{
wrap_here (n_spaces (2 + 2 * recurse));
}
annotate_field_begin (TYPE_FIELD_TYPE (type, i));
if (field_is_static (&TYPE_FIELD (type, i)))
fputs_filtered ("static ", stream);
fprintf_symbol_filtered (stream,
TYPE_FIELD_NAME (type, i),
current_language->la_language,
DMGL_PARAMS | DMGL_ANSI);
annotate_field_name_end ();
/* We tweak various options in a few cases below. */
value_print_options options_copy = *options;
value_print_options *opts = &options_copy;
/* Do not print leading '=' in case of anonymous
unions. */
if (strcmp (TYPE_FIELD_NAME (type, i), ""))
fputs_filtered (" = ", stream);
else
{
/* If this is an anonymous field then we want to consider it
as though it is at its parent's depth when it comes to the
max print depth. */
if (opts->max_depth != -1 && opts->max_depth < INT_MAX)
++opts->max_depth;
}
annotate_field_value ();
if (!field_is_static (&TYPE_FIELD (type, i))
&& TYPE_FIELD_PACKED (type, i))
{
struct value *v;
/* Bitfields require special handling, especially due to
byte order problems. */
if (TYPE_FIELD_IGNORE (type, i))
{
fputs_filtered ("<optimized out or zero length>", stream);
}
else if (value_bits_synthetic_pointer (val,
TYPE_FIELD_BITPOS (type,
i),
TYPE_FIELD_BITSIZE (type,
i)))
{
fputs_filtered (_("<synthetic pointer>"), stream);
}
else
{
opts->deref_ref = 0;
v = value_field_bitfield (type, i, valaddr, offset, val);
common_val_print (v, stream, recurse + 1,
opts, current_language);
}
}
else
{
if (TYPE_FIELD_IGNORE (type, i))
{
fputs_filtered ("<optimized out or zero length>",
stream);
}
else if (field_is_static (&TYPE_FIELD (type, i)))
{
struct value *v = NULL;
try
{
v = value_static_field (type, i);
}
catch (const gdb_exception_error &ex)
{
fprintf_filtered (stream,
_("<error reading variable: %s>"),
ex.what ());
}
cp_print_static_field (TYPE_FIELD_TYPE (type, i),
v, stream, recurse + 1, opts);
}
else if (i == vptr_fieldno && type == vptr_basetype)
{
int i_offset = offset + TYPE_FIELD_BITPOS (type, i) / 8;
struct type *i_type = TYPE_FIELD_TYPE (type, i);
if (valprint_check_validity (stream, i_type, i_offset, val))
{
CORE_ADDR addr;
addr = extract_typed_address (valaddr + i_offset, i_type);
print_function_pointer_address (opts,
get_type_arch (type),
addr, stream);
}
}
else
{
opts->deref_ref = 0;
val_print (TYPE_FIELD_TYPE (type, i),
offset + TYPE_FIELD_BITPOS (type, i) / 8,
address,
stream, recurse + 1, val, opts,
current_language);
}
}
annotate_field_end ();
}
if (dont_print_statmem == 0)
{
size_t obstack_final_size =
obstack_object_size (&dont_print_statmem_obstack);
if (obstack_final_size > statmem_obstack_initial_size)
{
/* In effect, a pop of the printed-statics stack. */
size_t shrink_bytes
= statmem_obstack_initial_size - obstack_final_size;
obstack_blank_fast (&dont_print_statmem_obstack, shrink_bytes);
}
if (last_set_recurse != recurse)
{
obstack_final_size =
obstack_object_size (&dont_print_stat_array_obstack);
if (obstack_final_size > stat_array_obstack_initial_size)
{
void *free_to_ptr =
(char *) obstack_next_free (&dont_print_stat_array_obstack)
- (obstack_final_size
- stat_array_obstack_initial_size);
obstack_free (&dont_print_stat_array_obstack,
free_to_ptr);
}
last_set_recurse = -1;
}
}
if (options->prettyformat)
{
fprintf_filtered (stream, "\n");
print_spaces_filtered (2 * recurse, stream);
}
} /* if there are data fields */
fprintf_filtered (stream, "}");
}
/* Like cp_print_value_fields, but find the runtime type of the object
and pass it as the `real_type' argument to cp_print_value_fields.
This function is a hack to work around the fact that
common_val_print passes the embedded offset to val_print, but not
the enclosing type. */
void
cp_print_value_fields_rtti (struct type *type,
const gdb_byte *valaddr, LONGEST offset,
CORE_ADDR address,
struct ui_file *stream, int recurse,
struct value *val,
const struct value_print_options *options,
struct type **dont_print_vb,
int dont_print_statmem)
{
struct type *real_type = NULL;
/* We require all bits to be valid in order to attempt a
conversion. */
if (!value_bits_any_optimized_out (val,
TARGET_CHAR_BIT * offset,
TARGET_CHAR_BIT * TYPE_LENGTH (type)))
{
struct value *value;
int full, using_enc;
LONGEST top;
/* Ugh, we have to convert back to a value here. */
value = value_from_contents_and_address (type, valaddr + offset,
address + offset);
type = value_type (value);
/* We don't actually care about most of the result here -- just
the type. We already have the correct offset, due to how
val_print was initially called. */
real_type = value_rtti_type (value, &full, &top, &using_enc);
}
if (!real_type)
real_type = type;
cp_print_value_fields (type, real_type, offset,
address, stream, recurse, val, options,
dont_print_vb, dont_print_statmem);
}
/* Special val_print routine to avoid printing multiple copies of
virtual baseclasses. */
static void
cp_print_value (struct type *type, struct type *real_type,
LONGEST offset,
CORE_ADDR address, struct ui_file *stream,
int recurse, struct value *val,
const struct value_print_options *options,
struct type **dont_print_vb)
{
struct type **last_dont_print
= (struct type **) obstack_next_free (&dont_print_vb_obstack);
struct obstack tmp_obstack = dont_print_vb_obstack;
int i, n_baseclasses = TYPE_N_BASECLASSES (type);
LONGEST thisoffset;
struct type *thistype;
const gdb_byte *valaddr = value_contents_for_printing (val);
if (dont_print_vb == 0)
{
/* If we're at top level, carve out a completely fresh chunk of
the obstack and use that until this particular invocation
returns. */
/* Bump up the high-water mark. Now alpha is omega. */
obstack_finish (&dont_print_vb_obstack);
}
for (i = 0; i < n_baseclasses; i++)
{
LONGEST boffset = 0;
int skip = 0;
struct type *baseclass = check_typedef (TYPE_BASECLASS (type, i));
const char *basename = TYPE_NAME (baseclass);
struct value *base_val = NULL;
if (BASETYPE_VIA_VIRTUAL (type, i))
{
struct type **first_dont_print
= (struct type **) obstack_base (&dont_print_vb_obstack);
int j = (struct type **)
obstack_next_free (&dont_print_vb_obstack) - first_dont_print;
while (--j >= 0)
if (baseclass == first_dont_print[j])
goto flush_it;
obstack_ptr_grow (&dont_print_vb_obstack, baseclass);
}
thisoffset = offset;
thistype = real_type;
try
{
boffset = baseclass_offset (type, i, valaddr, offset, address, val);
}
catch (const gdb_exception_error &ex)
{
if (ex.error == NOT_AVAILABLE_ERROR)
skip = -1;
else
skip = 1;
}
if (skip == 0)
{
if (BASETYPE_VIA_VIRTUAL (type, i))
{
/* The virtual base class pointer might have been
clobbered by the user program. Make sure that it
still points to a valid memory location. */
if ((boffset + offset) < 0
|| (boffset + offset) >= TYPE_LENGTH (real_type))
{
gdb::byte_vector buf (TYPE_LENGTH (baseclass));
if (target_read_memory (address + boffset, buf.data (),
TYPE_LENGTH (baseclass)) != 0)
skip = 1;
base_val = value_from_contents_and_address (baseclass,
buf.data (),
address + boffset);
baseclass = value_type (base_val);
thisoffset = 0;
boffset = 0;
thistype = baseclass;
}
else
{
base_val = val;
}
}
else
{
base_val = val;
}
}
/* Now do the printing. */
if (options->prettyformat)
{
fprintf_filtered (stream, "\n");
print_spaces_filtered (2 * recurse, stream);
}
fputs_filtered ("<", stream);
/* Not sure what the best notation is in the case where there is
no baseclass name. */
fputs_filtered (basename ? basename : "", stream);
fputs_filtered ("> = ", stream);
if (skip < 0)
val_print_unavailable (stream);
else if (skip > 0)
val_print_invalid_address (stream);
else
{
int result = 0;
if (options->max_depth > -1
&& recurse >= options->max_depth)
{
const struct language_defn *language = current_language;
gdb_assert (language->la_struct_too_deep_ellipsis != NULL);
fputs_filtered (language->la_struct_too_deep_ellipsis, stream);
}
else
{
/* Attempt to run an extension language pretty-printer on the
baseclass if possible. */
if (!options->raw)
result
= apply_ext_lang_val_pretty_printer (baseclass,
thisoffset + boffset,
value_address (base_val),
stream, recurse,
base_val, options,
current_language);
if (!result)
cp_print_value_fields (baseclass, thistype,
thisoffset + boffset,
value_address (base_val),
stream, recurse, base_val, options,
((struct type **)
obstack_base (&dont_print_vb_obstack)),
0);
}
}
fputs_filtered (", ", stream);
flush_it:
;
}
if (dont_print_vb == 0)
{
/* Free the space used to deal with the printing
of this type from top level. */
obstack_free (&dont_print_vb_obstack, last_dont_print);
/* Reset watermark so that we can continue protecting
ourselves from whatever we were protecting ourselves. */
dont_print_vb_obstack = tmp_obstack;
}
}
/* Print value of a static member. To avoid infinite recursion when
printing a class that contains a static instance of the class, we
keep the addresses of all printed static member classes in an
obstack and refuse to print them more than once.
VAL contains the value to print, TYPE, STREAM, RECURSE, and OPTIONS
have the same meanings as in c_val_print. */
static void
cp_print_static_field (struct type *type,
struct value *val,
struct ui_file *stream,
int recurse,
const struct value_print_options *options)
{
struct value_print_options opts;
if (value_entirely_optimized_out (val))
{
val_print_optimized_out (val, stream);
return;
}
struct type *real_type = check_typedef (type);
if (TYPE_CODE (real_type) == TYPE_CODE_STRUCT)
{
CORE_ADDR *first_dont_print;
CORE_ADDR addr;
int i;
first_dont_print
= (CORE_ADDR *) obstack_base (&dont_print_statmem_obstack);
i = obstack_object_size (&dont_print_statmem_obstack)
/ sizeof (CORE_ADDR);
while (--i >= 0)
{
if (value_address (val) == first_dont_print[i])
{
fputs_filtered ("<same as static member of an already"
" seen type>",
stream);
return;
}
}
addr = value_address (val);
obstack_grow (&dont_print_statmem_obstack, (char *) &addr,
sizeof (CORE_ADDR));
cp_print_value_fields (type, value_enclosing_type (val),
value_embedded_offset (val), addr,
stream, recurse, val,
options, NULL, 1);
return;
}
if (TYPE_CODE (real_type) == TYPE_CODE_ARRAY)
{
struct type **first_dont_print;
int i;
struct type *target_type = TYPE_TARGET_TYPE (type);
first_dont_print
= (struct type **) obstack_base (&dont_print_stat_array_obstack);
i = obstack_object_size (&dont_print_stat_array_obstack)
/ sizeof (struct type *);
while (--i >= 0)
{
if (target_type == first_dont_print[i])
{
fputs_filtered ("<same as static member of an already"
" seen type>",
stream);
return;
}
}
obstack_grow (&dont_print_stat_array_obstack,
(char *) &target_type,
sizeof (struct type *));
}
opts = *options;
opts.deref_ref = 0;
val_print (type,
value_embedded_offset (val),
value_address (val),
stream, recurse, val,
&opts, current_language);
}
/* Find the field in *SELF, or its non-virtual base classes, with
bit offset OFFSET. Set *SELF to the containing type and *FIELDNO
to the containing field number. If OFFSET is not exactly at the
start of some field, set *SELF to NULL. */
static void
cp_find_class_member (struct type **self_p, int *fieldno,
LONGEST offset)
{
struct type *self;
unsigned int i;
unsigned len;
*self_p = check_typedef (*self_p);
self = *self_p;
len = TYPE_NFIELDS (self);
for (i = TYPE_N_BASECLASSES (self); i < len; i++)
{
LONGEST bitpos = TYPE_FIELD_BITPOS (self, i);
QUIT;
if (offset == bitpos)
{
*fieldno = i;
return;
}
}
for (i = 0; i < TYPE_N_BASECLASSES (self); i++)
{
LONGEST bitpos = TYPE_FIELD_BITPOS (self, i);
LONGEST bitsize = 8 * TYPE_LENGTH (TYPE_FIELD_TYPE (self, i));
if (offset >= bitpos && offset < bitpos + bitsize)
{
*self_p = TYPE_FIELD_TYPE (self, i);
cp_find_class_member (self_p, fieldno, offset - bitpos);
return;
}
}
*self_p = NULL;
}
void
cp_print_class_member (const gdb_byte *valaddr, struct type *type,
struct ui_file *stream, const char *prefix)
{
enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
/* VAL is a byte offset into the structure type SELF_TYPE.
Find the name of the field for that offset and
print it. */
struct type *self_type = TYPE_SELF_TYPE (type);
LONGEST val;
int fieldno;
val = extract_signed_integer (valaddr,
TYPE_LENGTH (type),
byte_order);
/* Pointers to data members are usually byte offsets into an object.
Because a data member can have offset zero, and a NULL pointer to
member must be distinct from any valid non-NULL pointer to
member, either the value is biased or the NULL value has a
special representation; both are permitted by ISO C++. HP aCC
used a bias of 0x20000000; HP cfront used a bias of 1; g++ 3.x
and other compilers which use the Itanium ABI use -1 as the NULL
value. GDB only supports that last form; to add support for
another form, make this into a cp-abi hook. */
if (val == -1)
{
fprintf_filtered (stream, "NULL");
return;
}
cp_find_class_member (&self_type, &fieldno, val << 3);
if (self_type != NULL)
{
const char *name;
fputs_filtered (prefix, stream);
name = TYPE_NAME (self_type);
if (name)
fputs_filtered (name, stream);
else
c_type_print_base (self_type, stream, 0, 0, &type_print_raw_options);
fprintf_filtered (stream, "::");
fputs_filtered (TYPE_FIELD_NAME (self_type, fieldno), stream);
}
else
fprintf_filtered (stream, "%ld", (long) val);
}
void
_initialize_cp_valprint (void)
{
add_setshow_boolean_cmd ("static-members", class_support,
&user_print_options.static_field_print, _("\
Set printing of C++ static members."), _("\
Show printing of C++ static members."), NULL,
NULL,
show_static_field_print,
&setprintlist, &showprintlist);
add_setshow_boolean_cmd ("vtbl", class_support,
&user_print_options.vtblprint, _("\
Set printing of C++ virtual function tables."), _("\
Show printing of C++ virtual function tables."), NULL,
NULL,
show_vtblprint,
&setprintlist, &showprintlist);
add_setshow_boolean_cmd ("object", class_support,
&user_print_options.objectprint, _("\
Set printing of object's derived type based on vtable info."), _("\
Show printing of object's derived type based on vtable info."), NULL,
NULL,
show_objectprint,
&setprintlist, &showprintlist);
obstack_begin (&dont_print_stat_array_obstack,
32 * sizeof (struct type *));
obstack_begin (&dont_print_statmem_obstack,
32 * sizeof (CORE_ADDR));
obstack_begin (&dont_print_vb_obstack,
32 * sizeof (struct type *));
}
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