Stack clash mitigation

This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.

This patch series is designed to mitigate the problems exposed by the stack-clash exploits. As I've noted before, the way to address this class of problems is via a good stack probing strategy.

This has taken much longer than expected to pull together for submission. Sorry about that. However, the delay has led to some clear improvements on ppc, aarch64 and s390 as well as tests which aren't eyeballed, but instead are part of the testsuite.

This series introduces -fstack-check=clash which is a variant of -fstack-check designed to prevent "jumping the stack" as seen in the stack-clash exploits.