Index: libcxx/utils/ci/Dockerfile
===================================================================
--- libcxx/utils/ci/Dockerfile
+++ libcxx/utils/ci/Dockerfile
@@ -65,7 +65,7 @@
 # Install the most recent GCC
 ENV GCC_LATEST_VERSION=11
 RUN add-apt-repository ppa:ubuntu-toolchain-r/test
-RUN apt-get update && apt install -y gcc-$GCC_LATEST_VERSION g++-$GCC_LATEST_VERSION
+RUN apt-get update && apt install -y gcc-$GCC_LATEST_VERSION g++-$GCC_LATEST_VERSION gcc-$GCC_LATEST_VERSION-multilib g++-$GCC_LATEST_VERSION-multilib
 
 # Install a recent CMake
 RUN wget https://github.com/Kitware/CMake/releases/download/v3.21.1/cmake-3.21.1-linux-x86_64.sh -O /tmp/install-cmake.sh
Index: libunwind/test/forceunwind.pass.cpp
===================================================================
--- libunwind/test/forceunwind.pass.cpp
+++ libunwind/test/forceunwind.pass.cpp
@@ -9,12 +9,6 @@
 
 // REQUIRES: linux
 
-// TODO: Investigate these failures
-// XFAIL: asan, tsan, ubsan
-
-// TODO: Investigate this failure
-// XFAIL: 32bits-on-64bits
-
 // Basic test for _Unwind_ForcedUnwind.
 // See libcxxabi/test/forced_unwind* tests too.
 
Index: libunwind/test/frameheadercache_test.pass.cpp
===================================================================
--- libunwind/test/frameheadercache_test.pass.cpp
+++ libunwind/test/frameheadercache_test.pass.cpp
@@ -1,9 +1,3 @@
-// TODO: Investigate these failures
-// XFAIL: asan, tsan, ubsan
-
-// TODO: Investigate this failure
-// XFAIL: 32bits-on-64bits
-
 // The other libunwind tests don't test internal interfaces, so the include path
 // is a little wonky.
 #include "../src/config.h"
Index: libunwind/test/libunwind/test/config.py
===================================================================
--- libunwind/test/libunwind/test/config.py
+++ libunwind/test/libunwind/test/config.py
@@ -64,9 +64,13 @@
         self.cxx.compile_flags += ['-I' + libunwind_headers]
 
     def configure_link_flags_cxx_library(self):
-        # libunwind tests should not link with libc++
-        pass
+        # libunwind tests should not link with libc++ except when a sanitizer is used.
+        sanitizers = getattr(self.config, 'use_sanitizer', None)
+        if sanitizers is not None:
+            super().configure_link_flags_cxx_library()
 
     def configure_link_flags_abi_library(self):
-        # libunwind tests should not link with libc++abi
-        pass
+        # libunwind tests should not link with libc++ except when a sanitizer is used.
+        sanitizers = getattr(self.config, 'use_sanitizer', None)
+        if sanitizers is not None:
+            super().configure_link_flags_abi_library()
Index: libunwind/test/libunwind_01.pass.cpp
===================================================================
--- libunwind/test/libunwind_01.pass.cpp
+++ libunwind/test/libunwind_01.pass.cpp
@@ -1,12 +1,3 @@
-// TODO: Investigate these failures
-// XFAIL: asan, tsan, ubsan
-
-// TODO: Investigate these failures on x86_64 macOS
-// XFAIL: target=x86_64-apple-darwin{{.+}}
-
-// TODO: Investigate this failure
-// XFAIL: 32bits-on-64bits
-
 #include <libunwind.h>
 #include <stdlib.h>
 #include <string.h>
Index: libunwind/test/libunwind_02.pass.cpp
===================================================================
--- libunwind/test/libunwind_02.pass.cpp
+++ libunwind/test/libunwind_02.pass.cpp
@@ -1,9 +1,3 @@
-// TODO: Investigate these failures
-// XFAIL: asan, tsan, ubsan
-
-// TODO: Investigate this failure
-// XFAIL: 32bits-on-64bits
-
 #include <assert.h>
 #include <stdlib.h>
 #include <unwind.h>
Index: libunwind/test/lit.site.cfg.in
===================================================================
--- libunwind/test/lit.site.cfg.in
+++ libunwind/test/lit.site.cfg.in
@@ -44,6 +44,13 @@
 # Allow expanding substitutions that are based on other substitutions
 config.recursiveExpansionLimit = 10
 
+if platform.system() == 'Darwin':
+  config.substitutions.append(('%{exec}',
+      '{} --execdir %T --env DYLD_LIBRARY_PATH={} -- '.format(
+          config.executor,
+          pipes.quote(config.abi_library_root))
+  ))
+
 # Infer the test_exec_root from the build directory.
 config.test_exec_root = os.path.join(config.libunwind_obj_root, 'test')
 
Index: libunwind/test/remember_state_leak.pass.sh.s
===================================================================
--- libunwind/test/remember_state_leak.pass.sh.s
+++ libunwind/test/remember_state_leak.pass.sh.s
@@ -1,16 +1,8 @@
 # REQUIRES: target={{x86_64-.+-linux-gnu}}
+# UNSUPPORTED: 32bits-on-64bits
 # RUN: %{build}
 # RUN: %{run}
 
-// TODO: Investigate these failures
-// XFAIL: asan, tsan, ubsan
-
-// TODO: Investigate this failure
-// XFAIL: 32bits-on-64bits
-
-# TODO: Investigate this failure on GCC.
-# XFAIL: gcc
-
 # The following assembly is a translation of this code:
 #
 #   _Unwind_Reason_Code callback(int, _Unwind_Action, long unsigned int,
Index: libunwind/test/signal_frame.pass.cpp
===================================================================
--- libunwind/test/signal_frame.pass.cpp
+++ libunwind/test/signal_frame.pass.cpp
@@ -8,15 +8,8 @@
 //===----------------------------------------------------------------------===//
 
 // Ensure that functions marked as signal frames are reported as such.
-
-// TODO: Investigate these failures
-// XFAIL: asan, tsan, ubsan
-
-// TODO: Investigate this failure on macOS
-// XFAIL: target={{.+}}-apple-darwin{{.+}}
-
-// TODO: Investigate this failure
-// XFAIL: 32bits-on-64bits
+// cfi_signal_frame is only supported on DWARF based systems.
+// REQUIRES: linux
 
 // UNSUPPORTED: libunwind-arm-ehabi
 
Index: libunwind/test/signal_unwind.pass.cpp
===================================================================
--- libunwind/test/signal_unwind.pass.cpp
+++ libunwind/test/signal_unwind.pass.cpp
@@ -10,12 +10,6 @@
 // Ensure that the unwinder can cope with the signal handler.
 // REQUIRES: linux && (target={{aarch64-.+}} || target={{x86_64-.+}})
 
-// TODO: Investigate these failures
-// XFAIL: asan, tsan, ubsan
-
-// TODO: Investigate this failure
-// XFAIL: 32bits-on-64bits
-
 #include <assert.h>
 #include <dlfcn.h>
 #include <signal.h>
Index: libunwind/test/unw_getcontext.pass.cpp
===================================================================
--- libunwind/test/unw_getcontext.pass.cpp
+++ libunwind/test/unw_getcontext.pass.cpp
@@ -1,6 +1,3 @@
-// TODO: Investigate these failures
-// XFAIL: asan, tsan, ubsan
-
 #include <assert.h>
 #include <libunwind.h>
 
Index: libunwind/test/unwind_leaffunction.pass.cpp
===================================================================
--- libunwind/test/unwind_leaffunction.pass.cpp
+++ libunwind/test/unwind_leaffunction.pass.cpp
@@ -10,12 +10,6 @@
 // Ensure that leaf function can be unwund.
 // REQUIRES: linux && (target={{aarch64-.+}} || target={{x86_64-.+}})
 
-// TODO: Investigate these failures
-// XFAIL: asan, tsan, ubsan
-
-// TODO: Investigate this failure
-// XFAIL: 32bits-on-64bits
-
 #include <assert.h>
 #include <dlfcn.h>
 #include <signal.h>