Bug #2249
segfault Arch Linux GCC7
Description
I've compiled the 2.0.1 release and the current git master. Both segfault IF COMPILED WITH -O2.
I can avoid the segfault by compiling with -O0, but this is obviously not an ideal solution.
I've attached gdb output including a backtrace of the segfaulting 2.0.1 build.
This appears to be a similar issue to the one noted in these (separate) projects:
https://github.com/godotengine/godot/issues/4673
https://github.com/godotengine/godot/issues/4588
I believe this is a cast_to a NULL object in doomsday/sdk/libcore/include/de/filesys/node.h ,
but I have not managed to track it down.
Please let me know if I can offer any more helpful information.
Associated revisions
Fixed|Refactor: Potential crash in release build
According to the C++ standard, compilers are allowed to assume that
the `this` pointer is never null. This may allow them to optimize
certain operations better. However, the libcore.h AS_IS methods were
not compatible with this assumption (and the C++ standard), so they
were replaced with de::maybeAs<> template methods.
As a bonus, classes using these cast macros have fewer methods since
only the as<> methods remain in the class.
IssueID #2249
History
#1
Updated by skyjake over 7 years ago
Updated by - Tags set to GCC
- Status changed from New to In Progress
- Assignee set to skyjake
- Target version set to 2.0.2
The godot discussion hints at a possible workaround, I'll give it a try.
#2
Updated by fauxmight over 7 years ago
Updated by I'm sure this is obvious to you as the developer, but it appears the casts creating issues are probably those in the DENG2_AS_IS_METHODS() section of doomsday/sdk/libcore/include/de/libcore.h if I'm reading the code correctly.
#3
Updated by skyjake over 7 years ago
- % Done changed from 0 to 100
5f9c563853 seems to fix it for me when compiling with GCC 7.1.1 (on Fedora). I can include this fix in the stable branch as well after it's clear nothing has been broken.
#4
Updated by fauxmight over 7 years ago
This fix is great on Arch as well. Can close this issue as far as I'm concerned. Many thanks.
#5
Updated by skyjake over 7 years ago
- Status changed from In Progress to Closed
Fixed|Refactor: Potential crash in release build
According to the C++ standard, compilers are allowed to assume that
the `this` pointer is never null. This may allow them to optimize
certain operations better. However, the libcore.h AS_IS methods were
not compatible with this assumption (and the C++ standard), so they
were replaced with de::maybeAs<> template methods.
As a bonus, classes using these cast macros have fewer methods since
only the as<> methods remain in the class.
IssueID #2249