Re: [committed][gdb/testsuite] Fix exec_is_pie with gold linker

Tom de Vries
2020-05-25T15:29:13Z

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On 25-05-2020 16:54, Pedro Alves wrote:
> On 5/25/20 11:02 AM, Tom de Vries wrote:
>> Hi,
>>
>> When running test-case gdb.base/break-interp.exp with target board gold, we
>> run into:
>> ...
>> gdb compile failed, pie failed to generate PIE executable
>> ...
>>
>> The problem is that the proc exec_is_pie uses the PIE flag in the readelf -d
>> output, which doesn't seem to be set by the gold linker.
>
> Seems like a Gold bug?

Yeah, Andreas Schwab had the same comment in bugzilla, so I filed
PR26039 - "gold doesn't add PIE flag" (
https://sourceware.org/bugzilla/show_bug.cgi?id=26039 ).

> A comment in exec_is_pie explaining why we don't
> do the more obvious thing would be helpful, IMO.
>

Fixed in attached patch, committed.

Thanks,
- Tom

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[gdb/testsuite] Add comment in exec_is_pie

Add comment to exec_is_pie explaining why readelf -d output is not used.

gdb/testsuite/ChangeLog:

2020-05-25 Tom de Vries <tdevries@suse.de>

* lib/gdb.exp (exec_is_pie): Add comment.

---
gdb/testsuite/lib/gdb.exp | 3 +++
1 file changed, 3 insertions(+)

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 7177be941b..8e22941f0b 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -5509,6 +5509,9 @@ proc exec_is_pie { executable } {
return -1
}
set readelf_program [gdb_find_readelf]
+ # We're not testing readelf -d | grep "FLAGS_1.*Flags:.*PIE"
+ # because the PIE flag is not set by all versions of gold, see PR
+ # binutils/26039.
set res [catch {exec $readelf_program -h $executable} output]
if { $res != 0 } {
return -1