MDEV-26467: Use LOCK BTS also with the Microsoft compilerbb-10.6-MDEV-26467

Microsoft does not define inline assembler syntax for AMD64,
but it defines the intrinsic function _interlockedbittestandset()
that we can use.

ssux_lock_impl<bool>::rd_wait(): Remove a call to yield,
because writer.wr_lock() will take care of context switches
between loop iterations.

This addresses suggestions by Vladislav Vaintroub.

1 files changed, 47 insertions, 49 deletions

diff --git a/storage/innobase/sync/srw_lock.cc b/storage/innobase/sync/srw_lock.cc
index f38847f852b..7d26dd2b590 100644
--- a/storage/innobase/sync/srw_lock.cc
+++ b/storage/innobase/sync/srw_lock.cc
@@ -295,6 +295,35 @@ template void ssux_lock_impl<false>::wake();
 template void srw_mutex_impl<true>::wake();
 template void ssux_lock_impl<true>::wake();
 
+/*
+
+Unfortunately, compilers targeting IA-32 or AMD64 currently cannot
+translate the following single-bit operations into Intel 80386 instructions:
+
+     m.fetch_or(1<<b) & 1<<b       LOCK BTS b, m
+     m.fetch_and(~(1<<b)) & 1<<b   LOCK BTR b, m
+     m.fetch_xor(1<<b) & 1<<b      LOCK BTC b, m
+
+Hence, we will manually translate fetch_or() using GCC-style inline
+assembler code or a Microsoft intrinsic function.
+
+*/
+#if defined __GNUC__ && (defined __i386__ || defined __x86_64__)
+# define IF_FETCH_OR_GOTO(mem, bit, label)				\
+  __asm__ goto("lock btsl $" #bit ", %0\n\t"				\
+               "jc %l1" : : "m" (mem) : "cc", "memory" : label);
+# define IF_NOT_FETCH_OR_GOTO(mem, bit, label)				\
+  __asm__ goto("lock btsl $" #bit ", %0\n\t"				\
+               "jnc %l1" : : "m" (mem) : "cc", "memory" : label);
+#elif defined _MSC_VER && (defined _M_IX86 || defined _M_IX64)
+# define IF_FETCH_OR_GOTO(mem, bit, label)				\
+  if (_interlockedbittestandset(reinterpret_cast<volatile long*>(&mem), bit)) \
+    goto label;
+# define IF_NOT_FETCH_OR_GOTO(mem, bit, label)				\
+  if (!_interlockedbittestandset(reinterpret_cast<volatile long*>(&mem), bit))\
+    goto label;
+#endif
+
 template<>
 void srw_mutex_impl<true>::wait_and_lock()
 {
@@ -307,24 +336,15 @@ void srw_mutex_impl<true>::wait_and_lock()
     DBUG_ASSERT(~HOLDER & lk);
     if (lk & HOLDER)
       lk= lock.load(std::memory_order_relaxed);
-#if defined __GNUC__ && (defined __i386__ || defined __x86_64__)
-#elif defined _M_IX86||defined _M_X64||defined __i386__||defined __x86_64__
-    else if (lock.compare_exchange_weak(lk, lk | HOLDER,
-                                        std::memory_order_acquire,
-                                        std::memory_order_relaxed))
-      return;
-#else
-    else if (!((lk= lock.fetch_or(HOLDER, std::memory_order_relaxed)) &
-               HOLDER))
-      goto acquired;
-#endif
     else
     {
-#if defined __GNUC__ && (defined __i386__ || defined __x86_64__)
+#ifdef IF_NOT_FETCH_OR_GOTO
       static_assert(HOLDER == (1U << 31), "compatibility");
-      __asm__ goto("lock btsl $31, %0\n\t"
-                   "jnc %l1" : : "m" (*this) : "cc", "memory" : acquired);
+      IF_NOT_FETCH_OR_GOTO(*this, 31, acquired);
       lk|= HOLDER;
+#else
+      if (!((lk= lock.fetch_or(HOLDER, std::memory_order_relaxed)) & HOLDER))
+        goto acquired;
 #endif
       srw_pause(delay);
     }
@@ -338,36 +358,25 @@ void srw_mutex_impl<true>::wait_and_lock()
     if (lk & HOLDER)
     {
       wait(lk);
-#if defined __GNUC__ && (defined __i386__ || defined __x86_64__)
+#ifdef IF_FETCH_OR_GOTO
 reload:
 #endif
       lk= lock.load(std::memory_order_relaxed);
     }
-#if defined __GNUC__ && (defined __i386__ || defined __x86_64__)
     else
     {
+#ifdef IF_FETCH_OR_GOTO
       static_assert(HOLDER == (1U << 31), "compatibility");
-      __asm__ goto("lock btsl $31, %0\n\t"
-                   "jc %l1" : : "m" (*this) : "cc", "memory" : reload);
-acquired:
-      std::atomic_thread_fence(std::memory_order_acquire);
-      return;
-    }
-#elif defined _M_IX86||defined _M_X64||defined __i386__||defined __x86_64__
-    else if (lock.compare_exchange_weak(lk, lk | HOLDER,
-                                        std::memory_order_acquire,
-                                        std::memory_order_relaxed))
-      return;
+      IF_FETCH_OR_GOTO(*this, 31, reload);
 #else
-    else if (!((lk= lock.fetch_or(HOLDER, std::memory_order_relaxed)) &
-               HOLDER))
-    {
-acquired:
+      if ((lk= lock.fetch_or(HOLDER, std::memory_order_relaxed)) & HOLDER)
+        continue;
       DBUG_ASSERT(lk);
+#endif
+acquired:
       std::atomic_thread_fence(std::memory_order_acquire);
       return;
     }
-#endif
   }
 }
 
@@ -380,34 +389,24 @@ void srw_mutex_impl<false>::wait_and_lock()
     if (lk & HOLDER)
     {
       wait(lk);
-#if defined __GNUC__ && (defined __i386__ || defined __x86_64__)
+#ifdef IF_FETCH_OR_GOTO
 reload:
 #endif
       lk= lock.load(std::memory_order_relaxed);
     }
-#if defined __GNUC__ && (defined __i386__ || defined __x86_64__)
     else
     {
+#ifdef IF_FETCH_OR_GOTO
       static_assert(HOLDER == (1U << 31), "compatibility");
-      __asm__ goto("lock btsl $31, %0\n\t"
-                   "jc %l1" : : "m" (*this) : "cc", "memory" : reload);
-      std::atomic_thread_fence(std::memory_order_acquire);
-      return;
-    }
-#elif defined _M_IX86||defined _M_X64||defined __i386__||defined __x86_64__
-    else if (lock.compare_exchange_weak(lk, lk | HOLDER,
-                                        std::memory_order_acquire,
-                                        std::memory_order_relaxed))
-      return;
+      IF_FETCH_OR_GOTO(*this, 31, reload);
 #else
-    else if (!((lk= lock.fetch_or(HOLDER, std::memory_order_relaxed)) &
-               HOLDER))
-    {
+      if ((lk= lock.fetch_or(HOLDER, std::memory_order_relaxed)) & HOLDER)
+        continue;
       DBUG_ASSERT(lk);
+#endif
       std::atomic_thread_fence(std::memory_order_acquire);
       return;
     }
-#endif
   }
 }
 
@@ -456,7 +455,6 @@ void ssux_lock_impl<spinloop>::rd_wait()
     writer.wr_unlock();
     if (acquired)
       break;
-    std::this_thread::yield();
   }
 }