ARM stores the Thumb state in the least significant bit of the
function pointers. When compiling for ARM or Thumb, as all
instructions are at least 16-bit aligned, ignore the LSB when
computing the prefix hash location, so we can support both
pure Thumb and mixed ARM/Thumb binaries.
Fixes#62936
Reviewed By: MaskRay, simon_tatham
Differential Revision: https://reviews.llvm.org/D152484
KCFI traps should always be recoverable, but as Intrinsic::trap
is marked noreturn, it's not possible to continue execution after
handling the trap as the compiler is free to assume we never
return. Switch to debugtrap instead to ensure we have the option
to resume execution after the trap.
The KCFI sanitizer emits "kcfi" operand bundles to indirect
call instructions, which the LLVM back-end lowers into an
architecture-specific type check with a known machine instruction
sequence. Currently, KCFI operand bundle lowering is supported only
on 64-bit X86 and AArch64 architectures.
As a lightweight forward-edge CFI implementation that doesn't
require LTO is also useful for non-Linux low-level targets on
other machine architectures, add a generic KCFI operand bundle
lowering pass that's only used when back-end lowering support is not
available and allows -fsanitize=kcfi to be enabled in Clang on all
architectures.
This relands commit eb2a57ebc7aaad551af30462097a9e06c96db925 with
fixes.
Reviewed By: nickdesaulniers, MaskRay
Differential Revision: https://reviews.llvm.org/D135411
This reverts commit eb2a57ebc7aaad551af30462097a9e06c96db925.
llvm/include/llvm/Transforms/Instrumentation/KCFI.h including
llvm/CodeGen is a layering violation. We should use an approach where
Instrumementation/ doesn't need to include CodeGen/.
Sorry for not spotting this in the review.
The KCFI sanitizer emits "kcfi" operand bundles to indirect
call instructions, which the LLVM back-end lowers into an
architecture-specific type check with a known machine instruction
sequence. Currently, KCFI operand bundle lowering is supported only
on 64-bit X86 and AArch64 architectures.
As a lightweight forward-edge CFI implementation that doesn't
require LTO is also useful for non-Linux low-level targets on
other machine architectures, add a generic KCFI operand bundle
lowering pass that's only used when back-end lowering support is not
available and allows -fsanitize=kcfi to be enabled in Clang on all
architectures.
Reviewed By: nickdesaulniers, MaskRay
Differential Revision: https://reviews.llvm.org/D135411
