binutils-gdb/gdbsupport/tdesc.cc
Andrew Burgess caa7fd04f6 gdb: New maintenance command to print XML target description
This commit adds a new maintenance command that dumps the current
target description as an XML document.  This is a maintenance command
as I currently only see this being useful for GDB developers, or for
people debugging a new remote target.

By default the command will print whatever the current target
description is, whether this was delivered by the remote, loaded by
the user from a file, or if it is a built in target within GDB.

The command can also take an optional filename argument.  In this case
GDB loads a target description from the file, and then reprints it.
This could be useful for testing GDB's parsing of target descriptions,
or to check that GDB can successfully parse a particular XML
description.

It is worth noting that the XML description printed will not be an
exact copy of the document fed into GDB.  For example this minimal
input file:

  <target>
    <feature name="abc">
      <reg name="r1" bitsize="32"/>
    </feature>
  </target>

Will produce this output:

  (gdb) maint print xml-tdesc path/to/file.xml
  <?xml version="1.0"?>
  <!DOCTYPE target SYSTEM "gdb-target.dtd">
  <target>
    <feature name="abc">
      <reg name="r1" bitsize="32" type="int" regnum="0"/>
    </feature>
  </target>

Notice that GDB filled in both the 'type' and 'regnum' fields of the
<reg>.  I think this is actually a positive as it means we get to
really understand how GDB processed the document, if GDB made some
assumptions that differ to those the user expected then hopefully this
will bring those issues to the users attention.

To implement this I have tweaked the output produced by the
print_xml_feature which is defined within the gdbsupport/ directory.
The changes I have made to this class are:

  1. The <architecture>...</architecture> tags are now not produced if
  the architecture name is NULL.

  2. The <osabi>...</osabi> tags get a newline at the end.

  3. And, the whole XML document is indented using white space in a
  nested fashion (as in the example output above).

I think that these changes should be fine, the print_xml_feature class
is used:

  1. In gdbserver to generate an XML document to send as the target
  description to GDB.

  2. In GDB as part of a self-check function, a target_desc is
  converted to XML then parsed back into a target_desc.  We then check
  the before and after target_desc objects are the same.

  3. In the new 'maint print xml-tdesc' command.

In all of these use cases adding the extra white space should be fine.

gdbsupport/ChangeLog:

	* tdesc.cc (print_xml_feature::visit_pre): Use add_line to add
	output content, and call indent as needed in all overloaded
	variants.
	(print_xml_feature::visit_post): Likewise.
	(print_xml_feature::visit): Likewise.
	(print_xml_feature::add_line): Two new overloaded functions.
	* tdesc.h (print_xml_feature::indent): New member function.
	(print_xml_feature::add_line): Two new overloaded member
	functions.
	(print_xml_feature::m_depth): New member variable.

gdb/ChangeLog:

	* target-descriptions.c (tdesc_architecture_name): Protect against
	NULL pointer dereference.
	(maint_print_xml_tdesc_cmd): New function.
	(_initialize_target_descriptions): Register new 'maint print
	xml-tdesc' command and give it the filename completer.
	* NEWS: Mention new 'maint print xml-tdesc' command.

gdb/testsuite/ChangeLog:

	* gdb.xml/tdesc-reload.c: New file.
	* gdb.xml/tdesc-reload.exp: New file.
	* gdb.xml/maint-xml-dump-01.xml: New file.
	* gdb.xml/maint-xml-dump-02.xml: New file.
	* gdb.xml/maint-xml-dump.exp: New file.

gdb/doc/ChangeLog:

	* gdb.texinfo (Maintenance Commands): Document new 'maint print
	xml-desc' command.
2020-06-23 22:17:20 +01:00

448 lines
11 KiB
C++

/* Target description support for GDB.
Copyright (C) 2018-2020 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 "common-defs.h"
#include "gdbsupport/tdesc.h"
tdesc_reg::tdesc_reg (struct tdesc_feature *feature, const std::string &name_,
int regnum, int save_restore_, const char *group_,
int bitsize_, const char *type_)
: name (name_), target_regnum (regnum),
save_restore (save_restore_),
group (group_ != NULL ? group_ : ""),
bitsize (bitsize_),
type (type_ != NULL ? type_ : "<unknown>")
{
/* If the register's type is target-defined, look it up now. We may not
have easy access to the containing feature when we want it later. */
tdesc_type = tdesc_named_type (feature, type.c_str ());
}
/* Predefined types. */
static tdesc_type_builtin tdesc_predefined_types[] =
{
{ "bool", TDESC_TYPE_BOOL },
{ "int8", TDESC_TYPE_INT8 },
{ "int16", TDESC_TYPE_INT16 },
{ "int32", TDESC_TYPE_INT32 },
{ "int64", TDESC_TYPE_INT64 },
{ "int128", TDESC_TYPE_INT128 },
{ "uint8", TDESC_TYPE_UINT8 },
{ "uint16", TDESC_TYPE_UINT16 },
{ "uint32", TDESC_TYPE_UINT32 },
{ "uint64", TDESC_TYPE_UINT64 },
{ "uint128", TDESC_TYPE_UINT128 },
{ "code_ptr", TDESC_TYPE_CODE_PTR },
{ "data_ptr", TDESC_TYPE_DATA_PTR },
{ "ieee_half", TDESC_TYPE_IEEE_HALF },
{ "ieee_single", TDESC_TYPE_IEEE_SINGLE },
{ "ieee_double", TDESC_TYPE_IEEE_DOUBLE },
{ "arm_fpa_ext", TDESC_TYPE_ARM_FPA_EXT },
{ "i387_ext", TDESC_TYPE_I387_EXT }
};
void tdesc_feature::accept (tdesc_element_visitor &v) const
{
v.visit_pre (this);
for (const tdesc_type_up &type : types)
type->accept (v);
for (const tdesc_reg_up &reg : registers)
reg->accept (v);
v.visit_post (this);
}
bool tdesc_feature::operator== (const tdesc_feature &other) const
{
if (name != other.name)
return false;
if (registers.size () != other.registers.size ())
return false;
for (int ix = 0; ix < registers.size (); ix++)
{
const tdesc_reg_up &reg1 = registers[ix];
const tdesc_reg_up &reg2 = other.registers[ix];
if (reg1 != reg2 && *reg1 != *reg2)
return false;
}
if (types.size () != other.types.size ())
return false;
for (int ix = 0; ix < types.size (); ix++)
{
const tdesc_type_up &type1 = types[ix];
const tdesc_type_up &type2 = other.types[ix];
if (type1 != type2 && *type1 != *type2)
return false;
}
return true;
}
/* Lookup a predefined type. */
static struct tdesc_type *
tdesc_predefined_type (enum tdesc_type_kind kind)
{
for (int ix = 0; ix < ARRAY_SIZE (tdesc_predefined_types); ix++)
if (tdesc_predefined_types[ix].kind == kind)
return &tdesc_predefined_types[ix];
gdb_assert_not_reached ("bad predefined tdesc type");
}
/* See gdbsupport/tdesc.h. */
struct tdesc_type *
tdesc_named_type (const struct tdesc_feature *feature, const char *id)
{
/* First try target-defined types. */
for (const tdesc_type_up &type : feature->types)
if (type->name == id)
return type.get ();
/* Next try the predefined types. */
for (int ix = 0; ix < ARRAY_SIZE (tdesc_predefined_types); ix++)
if (tdesc_predefined_types[ix].name == id)
return &tdesc_predefined_types[ix];
return NULL;
}
/* See gdbsupport/tdesc.h. */
void
tdesc_create_reg (struct tdesc_feature *feature, const char *name,
int regnum, int save_restore, const char *group,
int bitsize, const char *type)
{
tdesc_reg *reg = new tdesc_reg (feature, name, regnum, save_restore,
group, bitsize, type);
feature->registers.emplace_back (reg);
}
/* See gdbsupport/tdesc.h. */
struct tdesc_type *
tdesc_create_vector (struct tdesc_feature *feature, const char *name,
struct tdesc_type *field_type, int count)
{
tdesc_type_vector *type = new tdesc_type_vector (name, field_type, count);
feature->types.emplace_back (type);
return type;
}
/* See gdbsupport/tdesc.h. */
tdesc_type_with_fields *
tdesc_create_struct (struct tdesc_feature *feature, const char *name)
{
tdesc_type_with_fields *type
= new tdesc_type_with_fields (name, TDESC_TYPE_STRUCT);
feature->types.emplace_back (type);
return type;
}
/* See gdbsupport/tdesc.h. */
void
tdesc_set_struct_size (tdesc_type_with_fields *type, int size)
{
gdb_assert (type->kind == TDESC_TYPE_STRUCT);
gdb_assert (size > 0);
type->size = size;
}
/* See gdbsupport/tdesc.h. */
tdesc_type_with_fields *
tdesc_create_union (struct tdesc_feature *feature, const char *name)
{
tdesc_type_with_fields *type
= new tdesc_type_with_fields (name, TDESC_TYPE_UNION);
feature->types.emplace_back (type);
return type;
}
/* See gdbsupport/tdesc.h. */
tdesc_type_with_fields *
tdesc_create_flags (struct tdesc_feature *feature, const char *name,
int size)
{
gdb_assert (size > 0);
tdesc_type_with_fields *type
= new tdesc_type_with_fields (name, TDESC_TYPE_FLAGS, size);
feature->types.emplace_back (type);
return type;
}
/* See gdbsupport/tdesc.h. */
tdesc_type_with_fields *
tdesc_create_enum (struct tdesc_feature *feature, const char *name,
int size)
{
gdb_assert (size > 0);
tdesc_type_with_fields *type
= new tdesc_type_with_fields (name, TDESC_TYPE_ENUM, size);
feature->types.emplace_back (type);
return type;
}
/* See gdbsupport/tdesc.h. */
void
tdesc_add_field (tdesc_type_with_fields *type, const char *field_name,
struct tdesc_type *field_type)
{
gdb_assert (type->kind == TDESC_TYPE_UNION
|| type->kind == TDESC_TYPE_STRUCT);
/* Initialize start and end so we know this is not a bit-field
when we print-c-tdesc. */
type->fields.emplace_back (field_name, field_type, -1, -1);
}
/* See gdbsupport/tdesc.h. */
void
tdesc_add_typed_bitfield (tdesc_type_with_fields *type, const char *field_name,
int start, int end, struct tdesc_type *field_type)
{
gdb_assert (type->kind == TDESC_TYPE_STRUCT
|| type->kind == TDESC_TYPE_FLAGS);
gdb_assert (start >= 0 && end >= start);
type->fields.emplace_back (field_name, field_type, start, end);
}
/* See gdbsupport/tdesc.h. */
void
tdesc_add_bitfield (tdesc_type_with_fields *type, const char *field_name,
int start, int end)
{
struct tdesc_type *field_type;
gdb_assert (start >= 0 && end >= start);
if (type->size > 4)
field_type = tdesc_predefined_type (TDESC_TYPE_UINT64);
else
field_type = tdesc_predefined_type (TDESC_TYPE_UINT32);
tdesc_add_typed_bitfield (type, field_name, start, end, field_type);
}
/* See gdbsupport/tdesc.h. */
void
tdesc_add_flag (tdesc_type_with_fields *type, int start,
const char *flag_name)
{
gdb_assert (type->kind == TDESC_TYPE_FLAGS
|| type->kind == TDESC_TYPE_STRUCT);
type->fields.emplace_back (flag_name,
tdesc_predefined_type (TDESC_TYPE_BOOL),
start, start);
}
/* See gdbsupport/tdesc.h. */
void
tdesc_add_enum_value (tdesc_type_with_fields *type, int value,
const char *name)
{
gdb_assert (type->kind == TDESC_TYPE_ENUM);
type->fields.emplace_back (name,
tdesc_predefined_type (TDESC_TYPE_INT32),
value, -1);
}
void print_xml_feature::visit_pre (const tdesc_feature *e)
{
add_line ("<feature name=\"%s\">", e->name.c_str ());
indent (1);
}
void print_xml_feature::visit_post (const tdesc_feature *e)
{
indent (-1);
add_line ("</feature>");
}
void print_xml_feature::visit (const tdesc_type_builtin *t)
{
error (_("xml output is not supported for type \"%s\"."), t->name.c_str ());
}
void print_xml_feature::visit (const tdesc_type_vector *t)
{
add_line ("<vector id=\"%s\" type=\"%s\" count=\"%d\"/>",
t->name.c_str (), t->element_type->name.c_str (), t->count);
}
void print_xml_feature::visit (const tdesc_type_with_fields *t)
{
const static char *types[] = { "struct", "union", "flags", "enum" };
gdb_assert (t->kind >= TDESC_TYPE_STRUCT && t->kind <= TDESC_TYPE_ENUM);
std::string tmp;
string_appendf (tmp,
"<%s id=\"%s\"", types[t->kind - TDESC_TYPE_STRUCT],
t->name.c_str ());
switch (t->kind)
{
case TDESC_TYPE_STRUCT:
case TDESC_TYPE_FLAGS:
if (t->size > 0)
string_appendf (tmp, " size=\"%d\"", t->size);
string_appendf (tmp, ">");
add_line (tmp);
for (const tdesc_type_field &f : t->fields)
{
tmp.clear ();
string_appendf (tmp, " <field name=\"%s\"", f.name.c_str ());
if (f.start != -1)
string_appendf (tmp, " start=\"%d\" end=\"%d\"", f.start,
f.end);
string_appendf (tmp, " type=\"%s\"/>",
f.type->name.c_str ());
add_line (tmp);
}
break;
case TDESC_TYPE_ENUM:
string_appendf (tmp, ">");
add_line (tmp);
for (const tdesc_type_field &f : t->fields)
add_line (" <field name=\"%s\" start=\"%d\"/>",
f.name.c_str (), f.start);
break;
case TDESC_TYPE_UNION:
string_appendf (tmp, ">");
add_line (tmp);
for (const tdesc_type_field &f : t->fields)
add_line (" <field name=\"%s\" type=\"%s\"/>",
f.name.c_str (), f.type->name.c_str ());
break;
default:
error (_("xml output is not supported for type \"%s\"."),
t->name.c_str ());
}
add_line ("</%s>", types[t->kind - TDESC_TYPE_STRUCT]);
}
void print_xml_feature::visit (const tdesc_reg *r)
{
std::string tmp;
string_appendf (tmp,
"<reg name=\"%s\" bitsize=\"%d\" type=\"%s\" regnum=\"%ld\"",
r->name.c_str (), r->bitsize, r->type.c_str (),
r->target_regnum);
if (r->group.length () > 0)
string_appendf (tmp, " group=\"%s\"", r->group.c_str ());
if (r->save_restore == 0)
string_appendf (tmp, " save-restore=\"no\"");
string_appendf (tmp, "/>");
add_line (tmp);
}
void print_xml_feature::visit_pre (const target_desc *e)
{
#ifndef IN_PROCESS_AGENT
add_line ("<?xml version=\"1.0\"?>");
add_line ("<!DOCTYPE target SYSTEM \"gdb-target.dtd\">");
add_line ("<target>");
indent (1);
if (tdesc_architecture_name (e))
add_line ("<architecture>%s</architecture>",
tdesc_architecture_name (e));
const char *osabi = tdesc_osabi_name (e);
if (osabi != nullptr)
add_line ("<osabi>%s</osabi>", osabi);
const std::vector<tdesc_compatible_info_up> &compatible_list
= tdesc_compatible_info_list (e);
for (const auto &c : compatible_list)
add_line ("<compatible>%s</compatible>",
tdesc_compatible_info_arch_name (c));
#endif
}
void print_xml_feature::visit_post (const target_desc *e)
{
indent (-1);
add_line ("</target>");
}
/* See gdbsupport/tdesc.h. */
void
print_xml_feature::add_line (const std::string &str)
{
string_appendf (*m_buffer, "%*s", m_depth, "");
string_appendf (*m_buffer, "%s", str.c_str ());
string_appendf (*m_buffer, "\n");
}
/* See gdbsupport/tdesc.h. */
void
print_xml_feature::add_line (const char *fmt, ...)
{
std::string tmp;
va_list ap;
va_start (ap, fmt);
string_vappendf (tmp, fmt, ap);
va_end (ap);
add_line (tmp);
}