Merge pull request #4444 from lioncash/volatile

common/atomic_ops: Don't cast away volatile from pointers

src/common/atomic_ops.cpp

@@ -14,50 +14,55 @@ namespace Common {
 
 #if _MSC_VER
 
-bool AtomicCompareAndSwap(u8 volatile* pointer, u8 value, u8 expected) {
+bool AtomicCompareAndSwap(volatile u8* pointer, u8 value, u8 expected) {
-    u8 result = _InterlockedCompareExchange8((char*)pointer, value, expected);
+    const u8 result =
+        _InterlockedCompareExchange8(reinterpret_cast<volatile char*>(pointer), value, expected);
     return result == expected;
 }
 
-bool AtomicCompareAndSwap(u16 volatile* pointer, u16 value, u16 expected) {
+bool AtomicCompareAndSwap(volatile u16* pointer, u16 value, u16 expected) {
-    u16 result = _InterlockedCompareExchange16((short*)pointer, value, expected);
+    const u16 result =
+        _InterlockedCompareExchange16(reinterpret_cast<volatile short*>(pointer), value, expected);
     return result == expected;
 }
 
-bool AtomicCompareAndSwap(u32 volatile* pointer, u32 value, u32 expected) {
+bool AtomicCompareAndSwap(volatile u32* pointer, u32 value, u32 expected) {
-    u32 result = _InterlockedCompareExchange((long*)pointer, value, expected);
+    const u32 result =
+        _InterlockedCompareExchange(reinterpret_cast<volatile long*>(pointer), value, expected);
     return result == expected;
 }
 
-bool AtomicCompareAndSwap(u64 volatile* pointer, u64 value, u64 expected) {
+bool AtomicCompareAndSwap(volatile u64* pointer, u64 value, u64 expected) {
-    u64 result = _InterlockedCompareExchange64((__int64*)pointer, value, expected);
+    const u64 result = _InterlockedCompareExchange64(reinterpret_cast<volatile __int64*>(pointer),
+                                                     value, expected);
     return result == expected;
 }
 
-bool AtomicCompareAndSwap(u64 volatile* pointer, u128 value, u128 expected) {
+bool AtomicCompareAndSwap(volatile u64* pointer, u128 value, u128 expected) {
-    return _InterlockedCompareExchange128((__int64*)pointer, value[1], value[0],
+    return _InterlockedCompareExchange128(reinterpret_cast<volatile __int64*>(pointer), value[1],
-                                          (__int64*)expected.data()) != 0;
+                                          value[0],
+                                          reinterpret_cast<__int64*>(expected.data())) != 0;
 }
 
 #else
 
-bool AtomicCompareAndSwap(u8 volatile* pointer, u8 value, u8 expected) {
+bool AtomicCompareAndSwap(volatile u8* pointer, u8 value, u8 expected) {
     return __sync_bool_compare_and_swap(pointer, expected, value);
 }
 
-bool AtomicCompareAndSwap(u16 volatile* pointer, u16 value, u16 expected) {
+bool AtomicCompareAndSwap(volatile u16* pointer, u16 value, u16 expected) {
     return __sync_bool_compare_and_swap(pointer, expected, value);
 }
 
-bool AtomicCompareAndSwap(u32 volatile* pointer, u32 value, u32 expected) {
+bool AtomicCompareAndSwap(volatile u32* pointer, u32 value, u32 expected) {
     return __sync_bool_compare_and_swap(pointer, expected, value);
 }
 
-bool AtomicCompareAndSwap(u64 volatile* pointer, u64 value, u64 expected) {
+bool AtomicCompareAndSwap(volatile u64* pointer, u64 value, u64 expected) {
     return __sync_bool_compare_and_swap(pointer, expected, value);
 }
 
-bool AtomicCompareAndSwap(u64 volatile* pointer, u128 value, u128 expected) {
+bool AtomicCompareAndSwap(volatile u64* pointer, u128 value, u128 expected) {
     unsigned __int128 value_a;
     unsigned __int128 expected_a;
     std::memcpy(&value_a, value.data(), sizeof(u128));

src/common/atomic_ops.h

@@ -8,10 +8,10 @@
 
 namespace Common {
 
-bool AtomicCompareAndSwap(u8 volatile* pointer, u8 value, u8 expected);
+bool AtomicCompareAndSwap(volatile u8* pointer, u8 value, u8 expected);
-bool AtomicCompareAndSwap(u16 volatile* pointer, u16 value, u16 expected);
+bool AtomicCompareAndSwap(volatile u16* pointer, u16 value, u16 expected);
-bool AtomicCompareAndSwap(u32 volatile* pointer, u32 value, u32 expected);
+bool AtomicCompareAndSwap(volatile u32* pointer, u32 value, u32 expected);
-bool AtomicCompareAndSwap(u64 volatile* pointer, u64 value, u64 expected);
+bool AtomicCompareAndSwap(volatile u64* pointer, u64 value, u64 expected);
-bool AtomicCompareAndSwap(u64 volatile* pointer, u128 value, u128 expected);
+bool AtomicCompareAndSwap(volatile u64* pointer, u128 value, u128 expected);
 
 } // namespace Common

src/core/memory.cpp

@@ -704,7 +704,7 @@ struct Memory::Impl {
         u8* page_pointer = current_page_table->pointers[vaddr >> PAGE_BITS];
         if (page_pointer != nullptr) {
             // NOTE: Avoid adding any extra logic to this fast-path block
-            T volatile* pointer = reinterpret_cast<T volatile*>(&page_pointer[vaddr]);
+            auto* pointer = reinterpret_cast<volatile T*>(&page_pointer[vaddr]);
             return Common::AtomicCompareAndSwap(pointer, data, expected);
         }
 
@@ -720,9 +720,8 @@ struct Memory::Impl {
         case Common::PageType::RasterizerCachedMemory: {
             u8* host_ptr{GetPointerFromRasterizerCachedMemory(vaddr)};
             system.GPU().InvalidateRegion(vaddr, sizeof(T));
-            T volatile* pointer = reinterpret_cast<T volatile*>(&host_ptr);
+            auto* pointer = reinterpret_cast<volatile T*>(&host_ptr);
             return Common::AtomicCompareAndSwap(pointer, data, expected);
-            break;
         }
         default:
             UNREACHABLE();
@@ -734,7 +733,7 @@ struct Memory::Impl {
         u8* const page_pointer = current_page_table->pointers[vaddr >> PAGE_BITS];
         if (page_pointer != nullptr) {
             // NOTE: Avoid adding any extra logic to this fast-path block
-            u64 volatile* pointer = reinterpret_cast<u64 volatile*>(&page_pointer[vaddr]);
+            auto* pointer = reinterpret_cast<volatile u64*>(&page_pointer[vaddr]);
             return Common::AtomicCompareAndSwap(pointer, data, expected);
         }
 
@@ -750,9 +749,8 @@ struct Memory::Impl {
         case Common::PageType::RasterizerCachedMemory: {
             u8* host_ptr{GetPointerFromRasterizerCachedMemory(vaddr)};
             system.GPU().InvalidateRegion(vaddr, sizeof(u128));
-            u64 volatile* pointer = reinterpret_cast<u64 volatile*>(&host_ptr);
+            auto* pointer = reinterpret_cast<volatile u64*>(&host_ptr);
             return Common::AtomicCompareAndSwap(pointer, data, expected);
-            break;
         }
         default:
             UNREACHABLE();