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Re: [PATCH][gdb] Fix build breaker with gcc 4.8
- From: Tom de Vries <tdevries at suse dot de>
- To: Pedro Alves <palves at redhat dot com>, gdb-patches at sourceware dot org
- Date: Wed, 19 Jun 2019 16:35:06 +0200
- Subject: Re: [PATCH][gdb] Fix build breaker with gcc 4.8
- References: <20190619110410.GA14131@delia> <bdbbe02e-4dba-1a62-553b-80d206743e33@redhat.com>
On 19-06-19 14:43, Pedro Alves wrote:
> On 6/19/19 12:04 PM, Tom de Vries wrote:
>> Hi,
>>
>> When compiling with gcc 4.8, we run into:
>> ...
>> /usr/include/c++/4.8/bits/unordered_map.h:100:18: required from \
>> ‘class std::unordered_map<sect_offset, std::vector<sect_offset> >’
>> src/gdb/dwarf2read.h:260:5: required from here
>> /usr/include/c++/4.8/bits/hashtable_policy.h:1070:12: error: invalid use of \
>> incomplete type ‘struct std::hash<sect_offset>’
>> ...
>>
>> Fix this by adding std::hash<sect_offset>.
>>
>> Build and reg-tested on x86_64-linux with gcc 4.8.
>>
>> OK for trunk?
>>
>
> hash_enum was added for this:
>
> https://sourceware.org/ml/gdb-patches/2017-12/msg00210.html
>
> Can you use it here?
>
> It's currently used in dwarf2read.c, here:
>
> std::unordered_map<sect_offset,
> dwarf2_per_cu_data *,
> gdb::hash_enum<sect_offset>>
>
Yes, that works for me.
OK for trunk?
Thanks,
- Tom
[gdb] Fix build breaker with gcc 4.8
When compiling with gcc 4.8, we run into:
...
/usr/include/c++/4.8/bits/unordered_map.h:100:18: required from \
â??class std::unordered_map<sect_offset, std::vector<sect_offset> >â??
src/gdb/dwarf2read.h:260:5: required from here
/usr/include/c++/4.8/bits/hashtable_policy.h:1070:12: error: invalid use of \
incomplete type â??struct std::hash<sect_offset>â??
...
Fix this by setting the Hash template parameter of the unordered_map to
gdb::hash_enum<sect_offset>, rather than using the default
std::hash<sect_offset>.
Build and reg-tested on x86_64-linux with gcc 4.8.
gdb/ChangeLog:
2019-06-19 Tom de Vries <tdevries@suse.de>
* dwarf2read.h (abstract_to_concrete): Change type to
std::unordered_map<sect_offset, std::vector<sect_offset>,
gdb::hash_enum<sect_offset>>.
---
gdb/dwarf2read.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/gdb/dwarf2read.h b/gdb/dwarf2read.h
index 776860e454..7113cfd384 100644
--- a/gdb/dwarf2read.h
+++ b/gdb/dwarf2read.h
@@ -24,6 +24,7 @@
#include "dwarf-index-cache.h"
#include "filename-seen-cache.h"
#include "gdb_obstack.h"
+#include "common/hash_enum.h"
/* Hold 'maintenance (set|show) dwarf' commands. */
extern struct cmd_list_element *set_dwarf_cmdlist;
@@ -256,7 +257,8 @@ public:
/* Mapping from abstract origin DIE to concrete DIEs that reference it as
DW_AT_abstract_origin. */
- std::unordered_map<sect_offset, std::vector<sect_offset>>
+ std::unordered_map<sect_offset, std::vector<sect_offset>, \
+ gdb::hash_enum<sect_offset>> \
abstract_to_concrete;
};