[BOLT] Change mutex implementation

[Elvina]

Summary

Changed acquire implementation to __atomic_test_and_set() and release to __atomic_clear() so it eliminates inline asm usage and is arch independent.

Elvina Yakubova,
Advanced Software Technology Lab, Huawei

[yota9]

LGTM
@maksfb Please take a look :)

[rafauler]

LGTM

bolt/runtime/common.h

void assert(bool Assertion, const char *Msg) {
   char Buf[BufSize];
   char *Ptr = Buf;
   Ptr = strCopy(Ptr, "Assertion failed: ");
   Ptr = strCopy(Ptr, Msg, BufSize - 40);
   Ptr = strCopy(Ptr, "\n");
   reportError(Buf, Ptr - Buf);
 }
 
-/// 1B mutex accessed by lock xchg
 class Mutex {
   volatile bool InUse{false};
 
 public:
-  bool acquire() {
-    bool Result = true;
-    asm volatile("lock; xchg %0, %1" : "+m"(InUse), "=r"(Result) : : "cc");
-    return !Result;
-  }
-  void release() { InUse = false; }
+  bool acquire() { return !__atomic_test_and_set(&InUse, __ATOMIC_ACQUIRE); }
+  void release() { __atomic_clear(&InUse, __ATOMIC_RELEASE); }
 };
 
 /// RAII wrapper for Mutex
 class Lock {
   Mutex &M;
   uint64_t SignalMask[1] = {};
 
 public: