x32 Fast tracepoints: IPA target descriptions

Building GDB for x32 fails building the IPA, with:

   .../src/gdb/gdbserver/linux-amd64-ipa.c: In function ‘const target_desc* get_ipa_tdesc(int)’:
   .../src/gdb/gdbserver/linux-amd64-ipa.c:182:14: error: ‘tdesc_amd64_avx_linux’ was not declared in this scope
	  return tdesc_amd64_avx_linux;
		 ^
   .../src/gdb/gdbserver/linux-amd64-ipa.c:184:14: error: ‘tdesc_amd64_mpx_linux’ was not declared in this scope
	  return tdesc_amd64_mpx_linux;
		 ^
   .../src/gdb/gdbserver/linux-amd64-ipa.c:186:14: error: ‘tdesc_amd64_avx_mpx_linux’ was not declared in this scope
	  return tdesc_amd64_avx_mpx_linux;
		 ^
  [...]

The problem is that the IPA is trying to use the 64-bit descriptions,
when it should be using the x32 ones.

gdb/gdbserver/ChangeLog:
2016-08-19  Pedro Alves  <palves@redhat.com>

	PR gdb/20415
	* Makefile.in (x32-linux-ipa.o, x32-avx-linux-ipa.o)
	(x32-avx512-linux-ipa.o): New rules.
	* configure.ac (x86_64-*-linux*): New x32 check.
	* configure.srv (ipa_x32_linux_regobj): New.
	(x86_64-*-linux*): Use $ipa_x32_linux_regobj if building for x32.
	* linux-amd64-ipa.c (get_ipa_tdesc) [__ILP32__]: Return x32
	descriptions.
	(initialize_low_tracepoint) [__ILP32__]: Initialize x32
	descriptions.
	* configure: Regenerate.

1 files changed, 31 insertions, 0 deletions

diff --git a/gdb/gdbserver/configure b/gdb/gdbserver/configure
index 889e35b..6b14b52 100755
--- a/gdb/gdbserver/configure
+++ b/gdb/gdbserver/configure
@@ -6796,6 +6796,37 @@ fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $gdb_cv_i386_is_x86_64" >&5
 $as_echo "$gdb_cv_i386_is_x86_64" >&6; }
     ;;
+
+  x86_64-*-linux*)
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking if building for x32" >&5
+$as_echo_n "checking if building for x32... " >&6; }
+if test "${gdb_cv_x86_is_x32+set}" = set; then :
+  $as_echo_n "(cached) " >&6
+else
+  save_CPPFLAGS="$CPPFLAGS"
+		    CPPFLAGS="$CPPFLAGS $CFLAGS"
+		    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+#if __x86_64__ && __ILP32__
+got it
+#endif
+
+_ACEOF
+if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
+  $EGREP "got it" >/dev/null 2>&1; then :
+  gdb_cv_x86_is_x32=yes
+else
+  gdb_cv_x86_is_x32=no
+fi
+rm -f conftest*
+
+		    CPPFLAGS="$save_CPPFLAGS"
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $gdb_cv_x86_is_x32" >&5
+$as_echo "$gdb_cv_x86_is_x32" >&6; }
+    ;;
+
   m68k-*-*)
     { $as_echo "$as_me:${as_lineno-$LINENO}: checking if building for Coldfire" >&5
 $as_echo_n "checking if building for Coldfire... " >&6; }