mirrors/yosys
3
0
Fork 0
mirror of https://github.com/YosysHQ/yosys synced 2025-06-06 06:03:23 +00:00
Code Activity

kernel/rtlil: Fixed the destruction guard for IdString

Browse source 
The guard is optimised out on some compilers under certain conditions (eg: LTO on GCC) as constant under C++ lifetime rules.
This is because the guard type's member is invalid to access (UB) after the type has been destroyed, resulting in
`destruct_guard.ok` being unable to be `false` according to the optimiser, based on the lifetime rules.

This patch still invokes UB (all accesses to the destroyed IdString instance are), but at least the optimiser
can't reason that destruct_guard_ok cannot be false and therefore it's safe to optimise out from its guard role.
This commit is contained in:
dragonmux 2023-07-26 20:46:56 +01:00
parent b04d0e09e8
commit b59c717245
No known key found for this signature in database
GPG key ID: 64861EA89B35507A
2 changed files with 6 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

1
kernel/rtlil.cc
View file

@ -30,6 +30,7 @@
YOSYS_NAMESPACE_BEGIN
bool RTLIL::IdString::destruct_guard_ok = false;
RTLIL::IdString::destruct_guard_t RTLIL::IdString::destruct_guard;
std::vector<char*> RTLIL::IdString::global_id_storage_;
dict<char*, int, hash_cstr_ops> RTLIL::IdString::global_id_index_;