On Fri, Nov 02, 2018 at 01:38:25PM -0500, Sudakshina Das wrote: > Hi > > This patch is part of a series that enables ARMv8.5-A in GCC and > adds Branch Target Identification Mechanism. > (https://developer.arm.com/products/architecture/cpu-architecture/a-profile/exploration-tools) > > NOTE: This patch is dependent on Sam Tebbs patch to deprecate > -msign-return-address and add new -mbranch-protection option > https://gcc.gnu.org/ml/gcc-patches/2018-11/msg00104.html > > This pass updates the CLI of -mbranch-protection to add "bti" as a new > type of branch protection and also add it its definition of "none" and > "standard". Since the BTI instructions, just like the return address > signing instructions are in the HINT space, this option is not limited > to ARMv8.5-A architecture version. > > The option does not really do anything functional. > The functional changes are in the next patch. I am initializing the > target variable aarch64_enable_bti to 2 since I am also adding a > configure option in a later patch and a value different from 0 and 1 > would help identify if its already been updated. > > Bootstrapped and regression tested with aarch64-none-linux-gnu. > Is this ok for trunk?
OK. Thanks, James > *** gcc/ChangeLog *** > > 2018-xx-xx Sudakshina Das <sudi....@arm.com> > > * config/aarch64/aarch64-protos.h (aarch64_bti_enabled): > Declare. > * config/aarch64/aarch64.c > (aarch64_handle_no_branch_protection): Disable bti for > -mbranch-protection=none. > (aarch64_handle_standard_branch_protection): Enable bti for > -mbranch-protection=standard. > (aarch64_handle_bti_protection): Enable bti for "bti" in the > string to -mbranch-protection. > (aarch64_bti_enabled): Check if bti is enabled. > * config/aarch64/aarch64.opt: Declare target variable. > * doc/invoke.texi: Add bti to the -mbranch-protection > documentation.
