Merge {i386,amd64}_linux_read_description

This commit merges i386_ and amd64_linux_read_description, renaming
both to x86_linux_read_description.

gdb/
2014-07-11  Gary Benson  <gbenson@redhat.com>

	* amd64-linux-nat.c (amd64_linux_read_description): Renamed to
	x86_linux_read_description.  All uses updated.  amd64-specific
	code conditionalized.  Conditionalized i386-specific code added.
	Redundant cast removed.
	* i386-linux-nat.c (i386_linux_read_description): Renamed to
	x86_linux_read_description.  All uses updated.  i386-specific
	code conditionalized.  Conditionalized amd64-specific code added.
	One sizeof replaced with the actual type it is describing.

1 files changed, 97 insertions, 82 deletions

diff --git a/gdb/amd64-linux-nat.c b/gdb/amd64-linux-nat.c
index d8e424a..c442878 100644
--- a/gdb/amd64-linux-nat.c
+++ b/gdb/amd64-linux-nat.c
@@ -1034,55 +1034,75 @@ amd64_linux_siginfo_fixup (siginfo_t *native, gdb_byte *inf, int direction)
     return 0;
 }
 
-/* Get Linux/x86 target description from running target.
-
-   Value of CS segment register:
-     1. 64bit process: 0x33.
-     2. 32bit process: 0x23.
-
-   Value of DS segment register:
-     1. LP64 process: 0x0.
-     2. X32 process: 0x2b.
- */
+#ifdef __x86_64__
+/* Value of CS segment register:
+     64bit process: 0x33
+     32bit process: 0x23  */
+#define AMD64_LINUX_USER64_CS 0x33
+
+/* Value of DS segment register:
+     LP64 process: 0x0
+     X32 process: 0x2b  */
+#define AMD64_LINUX_X32_DS 0x2b
+#endif
 
-#define AMD64_LINUX_USER64_CS	0x33
-#define AMD64_LINUX_X32_DS	0x2b
+/* Get Linux/x86 target description from running target.  */
 
 static const struct target_desc *
-amd64_linux_read_description (struct target_ops *ops)
+x86_linux_read_description (struct target_ops *ops)
 {
-  unsigned long cs;
-  unsigned long ds;
   int tid;
-  int is_64bit;
+  int is_64bit = 0;
+#ifdef __x86_64__
   int is_x32;
+#endif
   static uint64_t xcr0;
+  uint64_t xcr0_features_bits;
 
   /* GNU/Linux LWP ID's are process ID's.  */
   tid = ptid_get_lwp (inferior_ptid);
   if (tid == 0)
     tid = ptid_get_pid (inferior_ptid); /* Not a threaded program.  */
 
-  /* Get CS register.  */
-  errno = 0;
-  cs = ptrace (PTRACE_PEEKUSER, tid,
-	       offsetof (struct user_regs_struct, cs), 0);
-  if (errno != 0)
-    perror_with_name (_("Couldn't get CS register"));
-
-  is_64bit = cs == AMD64_LINUX_USER64_CS;
-
-  /* Get DS register.  */
-  errno = 0;
-  ds = ptrace (PTRACE_PEEKUSER, tid,
-	       offsetof (struct user_regs_struct, ds), 0);
-  if (errno != 0)
-    perror_with_name (_("Couldn't get DS register"));
-
-  is_x32 = ds == AMD64_LINUX_X32_DS;
+#ifdef __x86_64__
+  {
+    unsigned long cs;
+    unsigned long ds;
+
+    /* Get CS register.  */
+    errno = 0;
+    cs = ptrace (PTRACE_PEEKUSER, tid,
+		 offsetof (struct user_regs_struct, cs), 0);
+    if (errno != 0)
+      perror_with_name (_("Couldn't get CS register"));
+
+    is_64bit = cs == AMD64_LINUX_USER64_CS;
+
+    /* Get DS register.  */
+    errno = 0;
+    ds = ptrace (PTRACE_PEEKUSER, tid,
+		 offsetof (struct user_regs_struct, ds), 0);
+    if (errno != 0)
+      perror_with_name (_("Couldn't get DS register"));
+
+    is_x32 = ds == AMD64_LINUX_X32_DS;
+
+    if (sizeof (void *) == 4 && is_64bit && !is_x32)
+      error (_("Can't debug 64-bit process with 32-bit GDB"));
+  }
+#elif HAVE_PTRACE_GETFPXREGS
+  if (have_ptrace_getfpxregs == -1)
+    {
+      elf_fpxregset_t fpxregs;
 
-  if (sizeof (void *) == 4 && is_64bit && !is_x32)
-    error (_("Can't debug 64-bit process with 32-bit GDB"));
+      if (ptrace (PTRACE_GETFPXREGS, tid, 0, (int) &fpxregs) < 0)
+	{
+	  have_ptrace_getfpxregs = 0;
+	  have_ptrace_getregset = 0;
+	  return tdesc_i386_mmx_linux;
+	}
+    }
+#endif
 
   if (have_ptrace_getregset == -1)
     {
@@ -1094,7 +1114,7 @@ amd64_linux_read_description (struct target_ops *ops)
 
       /* Check if PTRACE_GETREGSET works.  */
       if (ptrace (PTRACE_GETREGSET, tid,
-		  (unsigned int) NT_X86_XSTATE, (long) &iov) < 0)
+		  (unsigned int) NT_X86_XSTATE, &iov) < 0)
 	have_ptrace_getregset = 0;
       else
 	{
@@ -1106,66 +1126,61 @@ amd64_linux_read_description (struct target_ops *ops)
 	}
     }
 
-  /* Check the native XCR0 only if PTRACE_GETREGSET is available.  */
-  if (have_ptrace_getregset && (xcr0 & I386_XSTATE_ALL_MASK))
+  /* Check the native XCR0 only if PTRACE_GETREGSET is available.  If
+     PTRACE_GETREGSET is not available then set xcr0_features_bits to
+     zero so that the "no-features" descriptions are returned by the
+     switches below.  */
+  if (have_ptrace_getregset)
+    xcr0_features_bits = xcr0 & I386_XSTATE_ALL_MASK;
+  else
+    xcr0_features_bits = 0;
+
+  if (is_64bit)
     {
-      switch (xcr0 & I386_XSTATE_ALL_MASK)
+#ifdef __x86_64__
+      switch (xcr0_features_bits)
 	{
-      case I386_XSTATE_MPX_AVX512_MASK:
-      case I386_XSTATE_AVX512_MASK:
-	if (is_64bit)
-	  {
-	    if (is_x32)
-	      return tdesc_x32_avx512_linux;
-	    else
-	      return tdesc_amd64_avx512_linux;
-	  }
-	else
-	  return tdesc_i386_avx512_linux;
+	case I386_XSTATE_MPX_AVX512_MASK:
+	case I386_XSTATE_AVX512_MASK:
+	  if (is_x32)
+	    return tdesc_x32_avx512_linux;
+	  else
+	    return tdesc_amd64_avx512_linux;
 	case I386_XSTATE_MPX_MASK:
-	  if (is_64bit)
-	    {
-	      if (is_x32)
-		return tdesc_x32_avx_linux; /* No MPX on x32 using AVX.  */
-	      else
-		return tdesc_amd64_mpx_linux;
-	    }
+	  if (is_x32)
+	    return tdesc_x32_avx_linux; /* No MPX on x32 using AVX.  */
 	  else
-	    return tdesc_i386_mpx_linux;
+	    return tdesc_amd64_mpx_linux;
 	case I386_XSTATE_AVX_MASK:
-	  if (is_64bit)
-	    {
-	      if (is_x32)
-		return tdesc_x32_avx_linux;
-	      else
-		return tdesc_amd64_avx_linux;
-	    }
+	  if (is_x32)
+	    return tdesc_x32_avx_linux;
 	  else
-	    return tdesc_i386_avx_linux;
+	    return tdesc_amd64_avx_linux;
 	default:
-	  if (is_64bit)
-	    {
-	      if (is_x32)
-		return tdesc_x32_linux;
-	      else
-		return tdesc_amd64_linux;
-	    }
+	  if (is_x32)
+	    return tdesc_x32_linux;
 	  else
-	    return tdesc_i386_linux;
+	    return tdesc_amd64_linux;
 	}
+#endif
     }
   else
     {
-      if (is_64bit)
+      switch (xcr0_features_bits)
 	{
-	  if (is_x32)
-	    return tdesc_x32_linux;
-	  else
-	    return tdesc_amd64_linux;
+	case I386_XSTATE_MPX_AVX512_MASK:
+	case I386_XSTATE_AVX512_MASK:
+	  return tdesc_i386_avx512_linux;
+	case I386_XSTATE_MPX_MASK:
+	  return tdesc_i386_mpx_linux;
+	case I386_XSTATE_AVX_MASK:
+	  return tdesc_i386_avx_linux;
+	default:
+	  return tdesc_i386_linux;
 	}
-      else
-	return tdesc_i386_linux;
     }
+
+  gdb_assert_not_reached ("failed to return tdesc");
 }
 
 /* Enable branch tracing.  */
@@ -1257,7 +1272,7 @@ _initialize_amd64_linux_nat (void)
   t->to_fetch_registers = amd64_linux_fetch_inferior_registers;
   t->to_store_registers = amd64_linux_store_inferior_registers;
 
-  t->to_read_description = amd64_linux_read_description;
+  t->to_read_description = x86_linux_read_description;
 
   /* Add btrace methods.  */
   t->to_supports_btrace = linux_supports_btrace;