[CMake][libcxx] Support HWASan

[phosek]

Summary

This is analogous to ASan.

[ldionne]

I assume we should also add the ability to test libc++ that way? If so, let's add it (libcxx/utils/libcxx/test/params.py:129). How is HWAddress different from Address? Is it worth adding a CI job?

[phosek]

In D127608#3578073, @ldionne wrote:

I assume we should also add the ability to test libc++ that way? If so, let's add it (libcxx/utils/libcxx/test/params.py:129).

Done.

How is HWAddress different from Address? Is it worth adding a CI job?

It uses TBI on AArch64 to reduce performance overhead. Do we have AArch64 machines in CI?

[phosek]

@ldionne Ping?

[Mordante]

Parts of this work seem the have landed in https://reviews.llvm.org/rG18014fe0a9bf41775e377db7a4214a159f79f257 can you rebase this patch and see whether there is anything left?

libcxx/CMakeLists.txt

if (USE_SANITIZER AND NOT MSVC)
     append_flags_if_supported(SANITIZER_FLAGS "-gline-tables-only")
 
     if (NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG" AND
             NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "RELWITHDEBINFO")
       append_flags_if_supported(SANITIZER_FLAGS "-gline-tables-only")
     endif()
     if (USE_SANITIZER STREQUAL "Address")
       append_flags(SANITIZER_FLAGS "-fsanitize=address")
+    elseif (USE_SANITIZER STREQUAL "HWAddress")
+      append_flags(SANITIZER_FLAGS "-fsanitize=hwaddress")
     elseif (USE_SANITIZER MATCHES "Memory(WithOrigins)?")
       append_flags(SANITIZER_FLAGS -fsanitize=memory)
       if (USE_SANITIZER STREQUAL "MemoryWithOrigins")
         append_flags(SANITIZER_FLAGS "-fsanitize-memory-track-origins")
       endif()
     elseif (USE_SANITIZER STREQUAL "Undefined")
       append_flags(SANITIZER_FLAGS "-fsanitize=undefined -fno-sanitize=vptr,function -fno-sanitize-recover=all")
     elseif (USE_SANITIZER STREQUAL "Address;Undefined" OR
             USE_SANITIZER STREQUAL "Undefined;Address")
       append_flags(SANITIZER_FLAGS "-fsanitize=address,undefined -fno-sanitize=vptr,function -fno-sanitize-recover=all")
+    elseif (USE_SANITIZER STREQUAL "HWAddress;Undefined" OR
+            USE_SANITIZER STREQUAL "Undefined;HWAddress")
+      append_flags(SANITIZER_FLAGS "-fsanitize=hwaddress,undefined -fno-sanitize=vptr,function -fno-sanitize-recover=all")
     elseif (USE_SANITIZER STREQUAL "Thread")
       append_flags(SANITIZER_FLAGS -fsanitize=thread)
     elseif (USE_SANITIZER STREQUAL "DataFlow")
       append_flags(SANITIZER_FLAGS -fsanitize=dataflow)
     else()
       message(WARNING "Unsupported value of LLVM_USE_SANITIZER: ${USE_SANITIZER}")
     endif()
   elseif(USE_SANITIZER AND MSVC)