[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, 13 insertions, 46 deletions

diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c
index 5c56a5d..24b76a7 100644
--- a/gdb/gdbserver/linux-x86-low.c
+++ b/gdb/gdbserver/linux-x86-low.c
@@ -757,7 +757,7 @@ x86_linux_read_description (void)
 	{
 	  have_ptrace_getfpxregs = 0;
 	  have_ptrace_getregset = 0;
-	  return tdesc_i386_mmx_linux;
+	  return i386_linux_read_description (X86_XSTATE_X87);
 	}
       else
 	have_ptrace_getfpxregs = 1;
@@ -873,31 +873,15 @@ x86_linux_read_description (void)
     }
   else
     {
-      if (xcr0_features)
-	{
-	  switch (xcr0 & X86_XSTATE_ALL_MASK)
-	    {
-	    case X86_XSTATE_AVX_MPX_AVX512_PKU_MASK:
-	      return tdesc_i386_avx_mpx_avx512_pku_linux;
-
-	    case (X86_XSTATE_AVX_AVX512_MASK):
-	      return tdesc_i386_avx_avx512_linux;
+      const target_desc *tdesc = NULL;
 
-	    case (X86_XSTATE_MPX_MASK):
-	      return tdesc_i386_mpx_linux;
-
-	    case (X86_XSTATE_AVX_MPX_MASK):
-	      return tdesc_i386_avx_mpx_linux;
+      if (xcr0_features)
+	  tdesc = i386_linux_read_description (xcr0 & X86_XSTATE_ALL_MASK);
 
-	    case (X86_XSTATE_AVX_MASK):
-	      return tdesc_i386_avx_linux;
+      if (tdesc == NULL)
+	tdesc = i386_linux_read_description (X86_XSTATE_SSE);
 
-	    default:
-	      return tdesc_i386_linux;
-	    }
-	}
-      else
-	return tdesc_i386_linux;
+      return tdesc;
     }
 
   gdb_assert_not_reached ("failed to return tdesc");
@@ -2912,23 +2896,10 @@ x86_get_ipa_tdesc_idx (void)
     return X86_TDESC_AVX_AVX512;
 #endif
 
-  if (tdesc == tdesc_i386_mmx_linux)
-    return X86_TDESC_MMX;
-  if (tdesc == tdesc_i386_linux || tdesc == tdesc_i386_linux_no_xml)
+  if (tdesc == tdesc_i386_linux_no_xml)
     return X86_TDESC_SSE;
-  if (tdesc == tdesc_i386_avx_linux)
-    return X86_TDESC_AVX;
-  if (tdesc == tdesc_i386_mpx_linux)
-    return X86_TDESC_MPX;
-  if (tdesc == tdesc_i386_avx_mpx_linux)
-    return X86_TDESC_AVX_MPX;
-  if (tdesc == tdesc_i386_avx_mpx_avx512_pku_linux)
-    return X86_TDESC_AVX_MPX_AVX512_PKU;
-  if (tdesc == tdesc_i386_avx_avx512_linux)
-    return X86_TDESC_AVX_AVX512;
 
-  /* If none tdesc is found, return the one with minimum features.  */
-  return X86_TDESC_MMX;
+  return i386_get_ipa_tdesc_idx (tdesc);
 }
 
 /* This is initialized assuming an amd64 target.
@@ -2997,16 +2968,12 @@ initialize_low_arch (void)
   copy_target_description (tdesc_amd64_linux_no_xml, tdesc_amd64_linux);
   tdesc_amd64_linux_no_xml->xmltarget = xmltarget_amd64_linux_no_xml;
 #endif
-  init_registers_i386_linux ();
-  init_registers_i386_mmx_linux ();
-  init_registers_i386_avx_linux ();
-  init_registers_i386_mpx_linux ();
-  init_registers_i386_avx_mpx_linux ();
-  init_registers_i386_avx_avx512_linux ();
-  init_registers_i386_avx_mpx_avx512_pku_linux ();
+
+  initialize_low_tdesc ();
 
   tdesc_i386_linux_no_xml = XNEW (struct target_desc);
-  copy_target_description (tdesc_i386_linux_no_xml, tdesc_i386_linux);
+  copy_target_description (tdesc_i386_linux_no_xml,
+			   i386_linux_read_description (X86_XSTATE_SSE_MASK));
   tdesc_i386_linux_no_xml->xmltarget = xmltarget_i386_linux_no_xml;
 
   initialize_regsets_info (&x86_regsets_info);