[GDBserver] Centralize tdesc for i386-linux

tdesc_i386_XXX_linux is used in many places in linux-x86-low.c and this
patch adds a new function i386_linux_read_description to return the right
tdesc according to xcr0.  i386_linux_read_description is quite similar to
the counterpart in GDB, and the following patch will share the duplicated
code, so this patch adds arch/tdesc.h includes the declarations of various
tdesc apis which are used by the shared code.  The generated c feature
files can include arch/tdesc.h only.

gdb/gdbserver:

2017-09-05  Yao Qi  <yao.qi@linaro.org>

	* configure.srv (srv_tgtobj): Append linux-x86-tdesc.o.
	(ipa_obj): Likewise.
	* linux-i386-ipa.c: Include common/x86-xstate.h
	(get_ipa_tdesc): Call i386_linux_read_description.
	(initialize_low_tracepoint): Don't call  init_registers_XXX
	functions, call initialize_low_tdesc instead.
	* linux-x86-low.c (x86_linux_read_description): Call
	i386_linux_read_description.
	(initialize_low_arch): Don't call init_registers_i386_XXX
	functions, call initialize_low_tdesc.
	* linux-x86-tdesc.c: New file.
	* linux-x86-tdesc.h (x86_linux_tdesc): New X86_TDESC_LAST.
	(i386_get_ipa_tdesc_idx): Declare.
	(i386_get_ipa_tdesc): Declare.
	(initialize_low_tdesc): Declare.

gdb:

2017-09-05  Yao Qi  <yao.qi@linaro.org>

	* arch/tdesc.h: New file.
	* regformats/regdat.sh: Generate code using tdesc_create_reg.
	* target-descriptions.c: Update comments.
	* target-descriptions.h: Include "arch/tdesc.h".  Remove the
	declarations.
	* features/i386/32bit-avx.c: Re-generated.
	* features/i386/32bit-avx512.c: Re-generated.
	* features/i386/32bit-core.c: Re-generated.
	* features/i386/32bit-linux.c: Re-generated.
	* features/i386/32bit-mpx.c: Re-generated.
	* features/i386/32bit-pkeys.c: Re-generated.
	* features/i386/32bit-sse.c: Re-generated.

1 files changed, 80 insertions, 0 deletions

diff --git a/gdb/arch/tdesc.h b/gdb/arch/tdesc.h
new file mode 100644
index 0000000..872df68
--- /dev/null
+++ b/gdb/arch/tdesc.h
@@ -0,0 +1,80 @@
+/* Copyright (C) 2006-2017 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/>.  */
+
+#ifndef ARCH_TDESC_H
+#define ARCH_TDESC_H 1
+
+struct tdesc_feature;
+struct tdesc_type;
+struct tdesc_reg;
+struct target_desc;
+
+/* Return the type associated with ID in the context of FEATURE, or
+   NULL if none.  */
+struct tdesc_type *tdesc_named_type (const struct tdesc_feature *feature,
+				     const char *id);
+
+/* Return the created feature named NAME in target description TDESC.  */
+struct tdesc_feature *tdesc_create_feature (struct target_desc *tdesc,
+					    const char *name);
+
+/* Return the created vector tdesc_type named NAME in FEATURE.  */
+struct tdesc_type *tdesc_create_vector (struct tdesc_feature *feature,
+					const char *name,
+					struct tdesc_type *field_type,
+					int count);
+
+/* Return the created struct tdesc_type named NAME in FEATURE.  */
+struct tdesc_type *tdesc_create_struct (struct tdesc_feature *feature,
+					const char *name);
+
+/* Return the created union tdesc_type named NAME in FEATURE.  */
+struct tdesc_type *tdesc_create_union (struct tdesc_feature *feature,
+				       const char *name);
+
+/* Return the created flags tdesc_type named NAME in FEATURE.  */
+struct tdesc_type *tdesc_create_flags (struct tdesc_feature *feature,
+				       const char *name,
+				       int size);
+
+/* Add a new field to TYPE.  FIELD_NAME is its name, and FIELD_TYPE is
+   its type.  */
+void tdesc_add_field (struct tdesc_type *type, const char *field_name,
+		      struct tdesc_type *field_type);
+
+/* Set the total length of TYPE.  Structs which contain bitfields may
+   omit the reserved bits, so the end of the last field may not
+   suffice.  */
+void tdesc_set_struct_size (struct tdesc_type *type, int size);
+
+/* Add a new untyped bitfield to TYPE.
+   Untyped bitfields become either uint32 or uint64 depending on the size
+   of the underlying type.  */
+void tdesc_add_bitfield (struct tdesc_type *type, const char *field_name,
+			 int start, int end);
+
+/* A flag is just a typed(bool) single-bit bitfield.
+   This function is kept to minimize changes in generated files.  */
+void tdesc_add_flag (struct tdesc_type *type, int start,
+		     const char *flag_name);
+
+/* Create a register in feature FEATURE.  */
+void tdesc_create_reg (struct tdesc_feature *feature, const char *name,
+		       int regnum, int save_restore, const char *group,
+		       int bitsize, const char *type);
+
+#endif /* ARCH_TDESC_H */