http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46706
Summary: global constructors does not work properly since
changes from bug 29141
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Severity: critical
Priority: P3
Component: c++
AssignedTo: [email protected]
ReportedBy: [email protected]
CC: [email protected]
Target: avr
In my opinion the bug 29141 is still pending and not fixed. I reported it there
but until now no reaction and I am not able to reopen the bug thus I open a new
one.
The proposed fix of bug 29141 rises another issue. Since this change, global
constructors does not work properly anymore. The fix uses register r20 within
the __do_global_ctors loop but this register could be clobbered by a
constructor that is called, leading to destructing the exit condition of the
__do_global_ctors loop. In new version of gcc (see bug 45263 but still not
confirmed) this is weakly fixed by pushing and poping r20 around the
constructor call. I would suggest using a register between r2-r17 instead of
r20. According to the compiler abi this should be a register that the called
routine has to save if it needs to use it.
In my eyes, this is a critical or maybe a blocker bug, because global objects
can not be used as long as r20 is used unprotected without pushing/poping, or
by using another register instead that is not faced by this problem.
Affected gcc versions 4.4.0 - 4.5.1
