Generate c for feature instead of tdesc

This patch changes Makefile and command "maint print c-files" so
that GDB can print c files for features instead target description.
Previously, we feed GDB a target description xml file, which generate
c files including multiple features.

With this patch, in Makefile, we wrap each feature xml file, and
create a temp target description which include only one feature.
Then, adjust the target description printer for them, and print
a c function for each given feature, so that we can use these
c functions later to create target description in a flexible way.

Before GDB prints c-tdesc, we need to set tdesc.  However, this involves
some validations in each gdbarch on these target descriptions, and this
make troubles to generate c file for each target feature when we feed GDB
a target description only including an optional feature (without some
mandatory feature), GDB just reject it, and don't print the c file.

What we need here is to translate xml file to object target_desc, and
translate the object target_desc to c file.  We don't have to involve
gdbarch validation in this process at all, so I modify command
"maint print c-tdesc" to have an optional argument which is the filename
of xml target description.  If the file name is provided, parse the
xml target description, create target_desc object, and print c file from
it.

gdb:

2017-05-22  Yao Qi  <yao.qi@linaro.org>

	* features/Makefile (FEATURE_XMLFILES): New.
	(FEATURE_CFILES): New.
	New rules.
	* features/i386/32bit-avx.c: Generated.
 	* features/i386/32bit-avx512.c: Generated.
 	* features/i386/32bit-core.c: Generated.
 	* features/i386/32bit-linux.c: Generated.
 	* features/i386/32bit-mpx.c: Generated.
 	* features/i386/32bit-pkeys.c: Generated.
 	* features/i386/32bit-sse.c: Generated.
 	* target-descriptions.c: Include algorithm.
	(tdesc_element_visitor): Add method visit_end.
	(print_c_tdesc): Implement visit_end.
	(print_c_tdesc:: m_filename_after_features): Move it to
	protected.
	(print_c_feature): New class.
	(maint_print_c_tdesc_cmd): Use print_c_feature if XML file
	name starts with "i386/32bit-".

gdb/doc:

2017-06-08  Yao Qi  <yao.qi@linaro.org>

	* gdb.texinfo (Maintenance Commands): Document optional
	argument of "maint print c-tdesc".

0 files changed, 0 insertions, 0 deletions