[sanitizer] Add the settings of Read and Write flags in SignalContext for LoongArch

The bit-30 in this `__flags` means the address error is due to memory load, and the
bit-31 means the address error is due to memory store. (see SC_ADDRERR_RD
and SC_ADDRERR_WR in kernel arch/loongarch/include/uapi/asm/sigcontext.h).

`illegal_write_test.cpp` and `illegal_read_test.cpp` have been tested and passed.

Reviewed By: SixWeining, xen0n, XiaodongLoong

Differential Revision: https://reviews.llvm.org/D137231

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
index 5d1bf95..f23ea9d 100644 (file)
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
@@ -1956,6 +1956,13 @@ SignalContext::WriteFlag SignalContext::GetWriteFlag() const {
   u64 esr;
   if (!Aarch64GetESR(ucontext, &esr)) return Unknown;
   return esr & ESR_ELx_WNR ? Write : Read;
+#elif defined(__loongarch__)
+  u32 flags = ucontext->uc_mcontext.__flags;
+  if (flags & SC_ADDRERR_RD)
+    return SignalContext::Read;
+  if (flags & SC_ADDRERR_WR)
+    return SignalContext::Write;
+  return SignalContext::Unknown;
 #elif defined(__sparc__)
   // Decode the instruction to determine the access type.
   // From OpenSolaris $SRC/uts/sun4/os/trap.c (get_accesstype).