On Thu, Jan 03, 2019 at 12:31:50PM -0800, Tom Stellard wrote:
On 01/03/2019 12:28 PM, Carlos O'Donell wrote:
> On 1/3/19 2:49 PM, Michael Cronenworth wrote:
>> Part of Fedora's default C/CXX flags include -fstack-clash-protection
>> but clang does not support this flag and has until a few weeks ago[1]
>> silently ignored the flag.
>>
>> What are clang apps who use Fedora's default flags supposed to do?
>> Are there clang default flag macros?
>>
>> Thanks, Michael
>>
>> [1]
https://bugzilla.redhat.com/show_bug.cgi?id=1658311
>
> You should reach out to Tom or Serge for comments :-)
>
The recommended solution for now is to filter out flags that clang does
not support.
See for example:
https://src.fedoraproject.org/rpms/libcxx/blob/master/f/libcxx.spec#_60
If the goal is to harden the binary without much performance overhead,
clang also proposes some unique flags, maybe it is worth considering
them?
https://clang.llvm.org/docs/SafeStack.html looks like a decent choice.