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.

gdb:

2017-07-26  Yao Qi  <yao.qi@linaro.org>

	* features/Makefile (CFILES): Rename with TDESC_CFILES.
	(FEATURE_XMLFILES): New.
	(FEATURE_CFILES): New.
	New rules.
	(clean-cfiles): Remove generated c files.
	* 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-".

1 files changed, 14 insertions, 0 deletions

diff --git a/gdb/features/i386/32bit-pkeys.c b/gdb/features/i386/32bit-pkeys.c
new file mode 100644
index 0000000..24a40aa3
--- /dev/null
+++ b/gdb/features/i386/32bit-pkeys.c
@@ -0,0 +1,14 @@
+/* THIS FILE IS GENERATED.  -*- buffer-read-only: t -*- vi:set ro:
+  Original: 32bit-pkeys.xml */
+
+#include "target-descriptions.h"
+
+static int
+create_feature_i386_32bit_pkeys (struct target_desc *result, long regnum)
+{
+  struct tdesc_feature *feature;
+
+  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.pkeys");
+  tdesc_create_reg (feature, "pkru", regnum++, 1, NULL, 32, "uint32");
+  return regnum;
+}