llvm-project/compiler-rt
Peter Collingbourne c336557f02 hwasan: Compatibility fixes for short granules.
We can't use short granules with stack instrumentation when targeting older
API levels because the rest of the system won't understand the short granule
tags stored in shadow memory.

Moreover, we need to be able to let old binaries (which won't understand
short granule tags) run on a new system that supports short granule
tags. Such binaries will call the __hwasan_tag_mismatch function when their
outlined checks fail. We can compensate for the binary's lack of support
for short granules by implementing the short granule part of the check in
the __hwasan_tag_mismatch function. Unfortunately we can't do anything about
inline checks, but I don't believe that we can generate these by default on
aarch64, nor did we do so when the ABI was fixed.

A new function, __hwasan_tag_mismatch_v2, is introduced that lets code
targeting the new runtime avoid redoing the short granule check. Because tag
mismatches are rare this isn't important from a performance perspective; the
main benefit is that it introduces a symbol dependency that prevents binaries
targeting the new runtime from running on older (i.e. incompatible) runtimes.

Differential Revision: https://reviews.llvm.org/D68059

llvm-svn: 373035
2019-09-27 01:02:10 +00:00
..
cmake [NFC] Invoke lipo from CMAKE_LIPO. 2019-09-24 23:48:42 +00:00
docs
include [compiler-rt] Add ubsan interface header. 2019-09-13 08:22:58 +00:00
lib hwasan: Compatibility fixes for short granules. 2019-09-27 01:02:10 +00:00
test hwasan: Compatibility fixes for short granules. 2019-09-27 01:02:10 +00:00
tools Add GWP-ASan fuzz target to compiler-rt/tools. 2019-08-27 18:28:07 +00:00
unittests [compiler-rt] Rename lit.*.cfg.* -> lit.*.cfg.py.* 2019-06-27 20:56:04 +00:00
utils Update generate_netbsd_ioctls.awk for NetBSD 9.99.3 2019-08-08 02:08:23 +00:00
www Adjust documentation for git migration. 2019-01-29 16:37:27 +00:00
.arcconfig [compiler-rt] Set up .arcconfig to point to new Diffusion CRT repository 2017-12-06 20:55:32 +00:00
.gitignore Add .pyc files to .gitignore to compiler-rt 2017-07-24 21:51:12 +00:00
CMakeLists.txt [compiler-rt] Don't use libcxx if it's not enabled by LLVM_ENABLE_PROJECTS 2019-08-28 02:41:14 +00:00
CODE_OWNERS.TXT
CREDITS.TXT
LICENSE.TXT Fix typos throughout the license files that somehow I and my reviewers 2019-01-21 09:52:34 +00:00
README.txt

README.txt

Compiler-RT
================================

This directory and its subdirectories contain source code for the compiler
support routines.

Compiler-RT is open source software. You may freely distribute it under the
terms of the license agreement found in LICENSE.txt.

================================