[PATCH][gdb/testsuite] Fix gdb.base/endianity.exp with gcc-4.8

[Tom de Vries <tdevries@suse.de>]

Hi,

When running test-case gdb.base/endianity.exp using gcc-4.8, we get:
...
(gdb) x/x &o.v^M
0x7fffffffd120: 0x00000004^M
(gdb) XFAIL: gdb.base/endianity.exp: x/x &o.v
x/xh &o.w^M
0x7fffffffd124: 0x0003^M
(gdb) FAIL: gdb.base/endianity.exp: x/xh &o.w
...

The gcc 4.8 compiler does not support the scalar_storage_order attribute, so
the testcase is compiled without that attribute, and the expected results are
different.

This is why there's the first XFAIL, and we could xfail the second FAIL for the
same reason.

Instead, fix this by adapting the expected values based on whether the attribute
has been used in endianity.c.

Also, remove hard-coding of the byte order in the expected memory printing.

Tested on x86_64-linux, with gcc-4.8, gcc-7, and clang-10.


Any comments?

Thanks,
- Tom

[gdb/testsuite] Fix gdb.base/endianity.exp with gcc-4.8

gdb/testsuite/ChangeLog:

2020-12-10  Tom de Vries  <tdevries@suse.de>

	PR testsuite/26953
	* gdb.base/endianity.c (ORDER_ATTR): New macro.
	(reverse): New variable.
	(struct otherendian): Use ORDER_ATTR.
	* gdb.base/endianity.exp: Use reverse variable to see if
	scalar_storage_order attribute was used.  Remove hard-coding of byte
	order in expected memory printing.

---
 gdb/testsuite/gdb.base/endianity.c   | 34 ++++++++++++++++------
 gdb/testsuite/gdb.base/endianity.exp | 56 ++++++++++++++++++++++++++++++++----
 2 files changed, 76 insertions(+), 14 deletions(-)

diff --git a/gdb/testsuite/gdb.base/endianity.c b/gdb/testsuite/gdb.base/endianity.c
index ef3b6d4fdb..2bc3d09502 100644
--- a/gdb/testsuite/gdb.base/endianity.c
+++ b/gdb/testsuite/gdb.base/endianity.c
@@ -17,6 +17,27 @@
 
 /* This tests the handling of dwarf attributes:
     DW_AT_endianity, DW_END_big, and DW_END_little.  */
+
+
+#if defined __GNUC__ && (__GNUC__ >= 6)
+/* Scalar_storage_order attribute supported.  */
+int reverse = 1;
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#define ORDER_ATTR \
+  __attribute__( ( scalar_storage_order( "big-endian" ) ) )
+#else
+#define ORDER_ATTR \
+  __attribute__( ( scalar_storage_order( "little-endian" ) ) )
+#endif
+
+#else
+
+#define ORDER_ATTR
+int reverse = 0;
+
+#endif
+
 struct otherendian
 {
   int v;
@@ -25,21 +46,16 @@ struct otherendian
   float f;
   __complex__ float cplx;
   double d;
-}
-#if defined __GNUC__ && (__GNUC__ >= 6)
-#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-__attribute__( ( scalar_storage_order( "big-endian" ) ) )
-#else
-__attribute__( ( scalar_storage_order( "little-endian" ) ) )
-#endif
-#endif
-;
+} ORDER_ATTR;
 
 void
 do_nothing (struct otherendian *c)
 {
 }
 
+int v = 4;
+short w = 3;
+
 int
 main (void)
 {
diff --git a/gdb/testsuite/gdb.base/endianity.exp b/gdb/testsuite/gdb.base/endianity.exp
index 2fa9ed3bf1..3f39be9239 100644
--- a/gdb/testsuite/gdb.base/endianity.exp
+++ b/gdb/testsuite/gdb.base/endianity.exp
@@ -34,12 +34,58 @@ gdb_test "print o.x = 2" "= 2"
 gdb_test "print o.f = 1.5" "= 1.5"
 gdb_test "print o.d = -23.125" "= -23.125"
 
-# scalar_storage_order requires gcc >= 6
-if { ([test_compiler_info {gcc-[0-5]-*}] || ![test_compiler_info gcc*]) } {
-  setup_xfail "*-*-*"
+proc reverse_hex { val } {
+    set r {}
+    foreach {a b} [split $val {}] {
+	set two "$a$b"
+	if { "$two" == "0x" } {
+	    continue
+	}
+	lappend r "$two"
+    }
+    set r [lreverse $r]
+    set r [join $r ""]
+    return "0x$r"
+}
+
+set reverse -1
+gdb_test_multiple "p reverse" "" {
+    -re -wrap "= 1" {
+	set reverse 1
+    }
+    -re -wrap "= 0" {
+	set reverse 0
+    }
+}
+
+if { $reverse != -1 } {
+
+    gdb_test_multiple "x/x &v" "" {
+	-wrap -re "$hex <v>:.*($hex)" {
+	    set v $expect_out(1,string)
+	    pass $gdb_test_name
+	    if { $reverse } {
+		set o_v [reverse_hex $v]
+	    } else {
+		set o_v $v
+	    }
+	    gdb_test "x/x &o.v" $o_v
+	}
+    }
+
+    gdb_test_multiple "x/xh &w" "" {
+	-wrap -re "$hex <w>:.*($hex)" {
+	    set w $expect_out(1,string)
+	    pass $gdb_test_name
+	    if { $reverse } {
+		set o_w [reverse_hex $w]
+	    } else {
+		set o_w $w
+	    }
+	    gdb_test "x/xh &o.w" $o_w
+	}
+    }
 }
-gdb_test "x/x &o.v" "0x04000000"
-gdb_test "x/xh &o.w" "0x0300"
 
 gdb_test "print o" "= {v = 4, w = 3, x = 2, f = 1.5, cplx = 1.25 \\+ 7.25i, d = -23.125}" \
     "print o after assignment"