[PATCH][gdb/testsuite] Fix error message test in dw2-error.exp

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

Hi,

the executable used in dw2-error.exp is compiled from a .s that was generated
with dwarf2 debug information but has been hand-edited to set the version in
the compilation unit header to 0x99:
...
.Ldebug_info0:
        .long   0x4e    # Length of Compilation Unit Info
        .value  0x99    # DWARF version number
        .long   .Ldebug_abbrev0 # Offset Into Abbrev. Section
...

Consequently, dwarf2read.c:read_comp_unit_head() interprets the compilation
unit header as dwarf5, which starts with fields unit_length (4 or 12 byte
unsigned), version (uhalf), and unit_type (ubyte). So, the unit_type
field is initialized from the first byte of .Ldebug_abbrev0 offset.

Using objdump, we find that the value of that byte is 0x64.
...
Contents of section .debug_info:
 ...
 00c0 00450000 0001804e 00000099 00640000  .E.....N.....d..
...

And indeed gdb errors out accordingly (note: 0x64 == 100):
...
(gdb) file outputs/gdb.dwarf2/dw2-error/dw2-error
Reading symbols from outputs/gdb.dwarf2/dw2-error/dw2-error...
Dwarf Error: wrong unit_type in compilation unit header
             (is 100, should be 1 or 2)
	     [in module outputs/gdb.dwarf2/dw2-error/dw2-error]
(no debugging symbols found)...done.
...

The test fails however because it expects the error message to contain 0
instead of the 100 we're seeing.

This patch fixes the failure by allowing any value for the unit_type in the
error message.

Tested on x86_64-linux.

OK for trunk?

Thanks,
- Tom

[gdb/testsuite] Fix error message test in dw2-error.exp

2018-06-19  Tom de Vries  <tdevries@suse.de>

	* gdb.dwarf2/dw2-error.exp: Allowing any value for the unit_type in
        the "wrong unit_type in compilation unit header" error message.

---
 gdb/testsuite/gdb.dwarf2/dw2-error.exp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gdb/testsuite/gdb.dwarf2/dw2-error.exp b/gdb/testsuite/gdb.dwarf2/dw2-error.exp
index e22667dea5..441e0f8db5 100644
--- a/gdb/testsuite/gdb.dwarf2/dw2-error.exp
+++ b/gdb/testsuite/gdb.dwarf2/dw2-error.exp
@@ -41,7 +41,7 @@ gdb_test_no_output "set breakpoint pending off"
 
 # First test that reading symbols fails.
 gdb_test "file $binfile" \
-    {Reading symbols.*Dwarf Error: wrong unit_type in compilation unit header \(is 0, should be 1 or 2\).*} \
+    {Reading symbols.*Dwarf Error: wrong unit_type in compilation unit header \(is [0-9]+, should be 1 or 2\).*} \
     "file $testfile"
 
 # Now check that we can still break given the minimal symbol.