[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, 16 insertions, 23 deletions

diff --git a/gdb/gdbserver/linux-i386-ipa.c b/gdb/gdbserver/linux-i386-ipa.c
index e9ac78b..54608da 100644
--- a/gdb/gdbserver/linux-i386-ipa.c
+++ b/gdb/gdbserver/linux-i386-ipa.c
@@ -22,6 +22,7 @@
 #include <sys/mman.h>
 #include "tracepoint.h"
 #include "linux-x86-tdesc.h"
+#include "common/x86-xstate.h"
 
 /* GDB register numbers.  */
 
@@ -250,27 +251,24 @@ initialize_fast_tracepoint_trampoline_buffer (void)
 const struct target_desc *
 get_ipa_tdesc (int idx)
 {
-  switch (idx)
+  if (idx >= X86_TDESC_LAST)
     {
-    case X86_TDESC_MMX:
-      return tdesc_i386_mmx_linux;
-    case X86_TDESC_SSE:
-      return tdesc_i386_linux;
-    case X86_TDESC_AVX:
-      return tdesc_i386_avx_linux;
-    case X86_TDESC_MPX:
-      return tdesc_i386_mpx_linux;
-    case X86_TDESC_AVX_MPX:
-      return tdesc_i386_avx_mpx_linux;
-    case X86_TDESC_AVX_AVX512:
-      return tdesc_i386_avx_avx512_linux;
-    case X86_TDESC_AVX_MPX_AVX512_PKU:
-      return tdesc_i386_avx_mpx_avx512_pku_linux;
-    default:
       internal_error (__FILE__, __LINE__,
 		      "unknown ipa tdesc index: %d", idx);
-      return tdesc_i386_linux;
     }
+
+  /* Map the tdesc index to xcr0 mask.  */
+  uint64_t idx2mask[X86_TDESC_LAST] = {
+    X86_XSTATE_X87_MASK,
+    X86_XSTATE_SSE_MASK,
+    X86_XSTATE_AVX_MASK,
+    X86_XSTATE_MPX_MASK,
+    X86_XSTATE_AVX_MPX_MASK,
+    X86_XSTATE_AVX_AVX512_MASK,
+    X86_XSTATE_AVX_MPX_AVX512_PKU_MASK,
+  };
+
+  return i386_linux_read_description (idx2mask[idx]);
 }
 
 /* Allocate buffer for the jump pads.  On i386, we can reach an arbitrary
@@ -291,12 +289,7 @@ alloc_jump_pad_buffer (size_t size)
 void
 initialize_low_tracepoint (void)
 {
-  init_registers_i386_mmx_linux ();
-  init_registers_i386_linux ();
-  init_registers_i386_avx_linux ();
-  init_registers_i386_mpx_linux ();
-  init_registers_i386_avx_avx512_linux ();
-  init_registers_i386_avx_mpx_avx512_pku_linux ();
+  initialize_low_tdesc ();
 
   initialize_fast_tracepoint_trampoline_buffer ();
 }