Hi! A severe ABI bug on AArch64 and especially on ARM 32-bit has been recently discovered and GCC 7.1 is going to have that ABI change in. For details see http://gcc.gnu.org/PR77728 gcc-7.1.1-0.16.fc{26,27} which I'll build tomorrow will contain the ABI changes as well as a -Wpsabi diagnostics (note:) on code that is changing the ABI. The ABI change should affect primarily just C++ code passing PODs by value where all the non-static data members and base classes are at most word aligned, but there are some static data members with doubleword or bigger alignment or there are typedefs or other nested types in the class/struct which are doubleword or bigger aligned, and are passed in certain positions in the argument list (passing them in even registers is fine, passing them in odd ones changes ABI, on the stack at odd positions might change the ABI too). For the typedefs, the broken ABI of GCC 5.2 to 7.0.1 has been actually not even self-consitent in some templates, earlier instantiation vs. lack thereof could affect the ABI. GCC 5.1 and earlier for structs used to match earlier AAPCS version and had different rules and issues. Could somebody from rel-eng perform a test mass rebuild on armv7hl and aarch64 of F26 to determine which packages are affected by the ABI changes so that we could rebuild only those that actually need changing? If grepping for note: is not good enough for the test mass rebuild, I could hack up a test compiler that does something different when it encounters this (say abort if it encounters this and some special env var is set, or writes something into some /tmp/ file and let some brp script collect info from there, etc.). Jakub _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx
