关于pr170的修改讨论

[axiangyushanhaijing]

pr170 其中修改了 公共区域代码，目前如果回退会报错，需要重新研究修改。

[axiangyushanhaijing]

对 pr170 进行分析。
参考之前的修改讨论 消除warning的comment，在回退对公共代码的修改的同时，还需要考虑消除返回值的warning ：“warning: no return statement in function returning non-void [-Wreturn-type]”，所以需要对Atomic::PlatformLoad以及Atomic::PlatformStore 修改。同时参考zero版本的实现：

template<>
template<typename T>
inline T Atomic::PlatformLoad<8>::operator()(T const volatile* src) const {
  STATIC_ASSERT(8 == sizeof(T));
  volatile int64_t dest;
  os::atomic_copy64(reinterpret_cast<const volatile int64_t*>(src), reinterpret_cast<volatile int64_t*>(&dest));
  return PrimitiveConversions::cast<T>(dest);
}

template<>
template<typename T>
inline void Atomic::PlatformStore<8>::operator()(T store_value,
                                                 T volatile* dest) const {
  STATIC_ASSERT(8 == sizeof(T));
  os::atomic_copy64(reinterpret_cast<const volatile int64_t*>(&store_value), reinterpret_cast<volatile int64_t*>(dest));
}

重新修改：

diff --git a/src/hotspot/os_cpu/linux_riscv32/atomic_linux_riscv32.hpp b/src/hotspot/os_cpu/linux_riscv32/atomic_linux_riscv32.hpp
index 6f211c80fb..436c6fc7e4 100644
--- a/src/hotspot/os_cpu/linux_riscv32/atomic_linux_riscv32.hpp
+++ b/src/hotspot/os_cpu/linux_riscv32/atomic_linux_riscv32.hpp
@@ -110,13 +110,21 @@ inline T Atomic::PlatformCmpxchg<4>::operator()(T exchange_value,
   return rv;
 }
 
-/*template<>
+template<>
 template<typename T>
-inline T Atomic::PlatformLoad<8>::operator()(T const volatile* src) const {}
+inline T Atomic::PlatformLoad<8>::operator()(T const volatile* src) const {
+  STATIC_ASSERT(8 == sizeof(T));
+  volatile int64_t dest;
+  os::atomic_copy64(reinterpret_cast<const volatile int64_t*>(src), reinterpret_cast<volatile int64_t*>(&dest));
+  return PrimitiveConversions::cast<T>(dest);
+}
 
 template<>
 template<typename T>
 inline void Atomic::PlatformStore<8>::operator()(T store_value,
-                                                 T volatile* dest) const {}
-*/
+                                                 T volatile* dest) const {
+  STATIC_ASSERT(8 == sizeof(T));
+  os::atomic_copy64(reinterpret_cast<const volatile int64_t*>(&store_value), reinterpret_cast<volatile int64_t*>(dest));
+  }
+
 #endif // OS_CPU_LINUX_RISCV32_VM_ATOMIC_LINUX_RISCV32_HPP
diff --git a/src/hotspot/share/runtime/atomic.hpp b/src/hotspot/share/runtime/atomic.hpp
index 5067031fa2..57bca10c21 100644
--- a/src/hotspot/share/runtime/atomic.hpp
+++ b/src/hotspot/share/runtime/atomic.hpp
@@ -416,7 +416,7 @@ template<size_t byte_size>
 struct Atomic::PlatformLoad {
   template<typename T>
   T operator()(T const volatile* dest) const {
-    //STATIC_ASSERT(sizeof(T) <= sizeof(void*)); // wide atomics need specialization
+    STATIC_ASSERT(sizeof(T) <= sizeof(void*)); // wide atomics need specialization
     return *dest;
   }
 };
@@ -486,7 +486,7 @@ struct Atomic::PlatformStore {
   template<typename T>
   void operator()(T new_value,
                   T volatile* dest) const {
-//    STATIC_ASSERT(sizeof(T) <= sizeof(void*)); // wide atomics need specialization
+  STATIC_ASSERT(sizeof(T) <= sizeof(void*)); // wide atomics need specialization
     (void)const_cast<T&>(*dest = new_value);
   }
 };

[axiangyushanhaijing]

已提交 pr341，修复后对当前进度无影响。