[libFuzzer] Enable for SystemZ

* Add SystemZ to the list of supported architectures.

* XFAIL a few tests.

Coverage reporting is broken, and is not easy to fix (see comment in
coverage.test). Interaction with sanitizers needs to be investigated
more thoroughly, since they appear to reduce coverage in certain cases.

compiler-rt/cmake/config-ix.cmake

@@ -305,7 +305,7 @@ else()
 endif()
 
 if(OS_NAME MATCHES "Linux")
-  set(ALL_FUZZER_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM64})
+  set(ALL_FUZZER_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM64} ${S390X})
 elseif (OS_NAME MATCHES "Windows")
   set(ALL_FUZZER_SUPPORTED_ARCH ${X86} ${X86_64})
 elseif(OS_NAME MATCHES "Android")

compiler-rt/test/fuzzer/coverage.test

@@ -1,5 +1,7 @@
 # FIXME: Disabled on Windows because -fPIC cannot be used to compile for Windows.
 UNSUPPORTED: windows
+# FIXME: CreatePCArray() emits PLT stub addresses for entry blocks, which are ignored by TracePC::PrintCoverage().
+XFAIL: s390x
 RUN: %cpp_compiler -mllvm -use-unknown-locations=Disable  %S/NullDerefTest.cpp -o %t-NullDerefTest
 RUN: %cpp_compiler -mllvm -use-unknown-locations=Disable %S/DSO1.cpp -fPIC %ld_flags_rpath_so1 -O0 -shared -o %dynamiclib1
 RUN: %cpp_compiler -mllvm -use-unknown-locations=Disable %S/DSO2.cpp -fPIC %ld_flags_rpath_so2 -O0 -shared -o %dynamiclib2

compiler-rt/test/fuzzer/msan.test

@@ -1,3 +1,5 @@
+FIXME: Fails to find BINGO on s390x.
+XFAIL: s390x
 REQUIRES: msan
 RUN: %msan_compiler %S/SimpleTestStdio.cpp -o %t
 RUN: not %run %t -seed=1 -runs=10000000 2>&1 | FileCheck %s --check-prefix=NO-REPORT

compiler-rt/test/fuzzer/swap-cmp.test

@@ -1,3 +1,5 @@
+# FIXME: Fails to find BINGO with ASAN on s390x, work fine without ASAN.
+XFAIL: s390x
 RUN: %cpp_compiler %S/SwapCmpTest.cpp -o %t-SwapCmpTest
 CHECK: BINGO
 RUN: not %run %t-SwapCmpTest -seed=1 -runs=10000000 2>&1 | FileCheck %s