[Arm64] Use half barriers for IL Volatile implementation

4 files changed, 28 insertions, 10 deletions

diff --git a/src/jit/codegen.h b/src/jit/codegen.h
index 30a84e038d..b1b073862d 100644
--- a/src/jit/codegen.h
+++ b/src/jit/codegen.h
@@ -959,7 +959,11 @@ public:
 
     void instGen_Return(unsigned stkArgSize);
 
+#ifdef _TARGET_ARM64_
+    void instGen_MemoryBarrier(insBarrier barrierType = INS_BARRIER_SY);
+#else
     void instGen_MemoryBarrier();
+#endif
 
     void instGen_Set_Reg_To_Zero(emitAttr size, regNumber reg, insFlags flags = INS_FLAGS_DONT_CARE);
 
diff --git a/src/jit/codegenarm64.cpp b/src/jit/codegenarm64.cpp
index c7c350ef3b..4ef7ef3c46 100644
--- a/src/jit/codegenarm64.cpp
+++ b/src/jit/codegenarm64.cpp
@@ -2565,7 +2565,7 @@ void CodeGen::genCodeForInitBlkUnroll(GenTreeBlk* initBlkNode)
 
     if (initBlkNode->gtFlags & GTF_BLK_VOLATILE)
     {
-        // issue a full memory barrier before volatile an initBlockUnroll operation
+        // issue a full memory barrier before a volatile an initBlockUnroll operation
         instGen_MemoryBarrier();
     }
 
@@ -2714,7 +2714,7 @@ void CodeGen::genCodeForCpBlkUnroll(GenTreeBlk* cpBlkNode)
 
     if (cpBlkNode->gtFlags & GTF_BLK_VOLATILE)
     {
-        // issue a full memory barrier before & after a volatile CpBlkUnroll operation
+        // issue a full memory barrier before a volatile CpBlkUnroll operation
         instGen_MemoryBarrier();
     }
 
@@ -2794,8 +2794,8 @@ void CodeGen::genCodeForCpBlkUnroll(GenTreeBlk* cpBlkNode)
 
     if (cpBlkNode->gtFlags & GTF_BLK_VOLATILE)
     {
-        // issue a full memory barrier before & after a volatile CpBlkUnroll operation
-        instGen_MemoryBarrier();
+        // issue a INS_BARRIER_LD after a volatile CpBlkUnroll operation
+        instGen_MemoryBarrier(INS_BARRIER_LD);
     }
 }
 
@@ -2877,7 +2877,7 @@ void CodeGen::genCodeForCpObj(GenTreeObj* cpObjNode)
 
     if (cpObjNode->gtFlags & GTF_BLK_VOLATILE)
     {
-        // issue a full memory barrier before & after a volatile CpObj operation
+        // issue a full memory barrier before a volatile CpObj operation
         instGen_MemoryBarrier();
     }
 
@@ -2955,8 +2955,8 @@ void CodeGen::genCodeForCpObj(GenTreeObj* cpObjNode)
 
     if (cpObjNode->gtFlags & GTF_BLK_VOLATILE)
     {
-        // issue a full memory barrier before & after a volatile CpObj operation
-        instGen_MemoryBarrier();
+        // issue a INS_BARRIER_LD after a volatile CpObj operation
+        instGen_MemoryBarrier(INS_BARRIER_LD);
     }
 
     // Clear the gcInfo for REG_WRITE_BARRIER_SRC_BYREF and REG_WRITE_BARRIER_DST_BYREF.
diff --git a/src/jit/codegenarmarch.cpp b/src/jit/codegenarmarch.cpp
index e8391d1512..911f07e2cc 100644
--- a/src/jit/codegenarmarch.cpp
+++ b/src/jit/codegenarmarch.cpp
@@ -1343,8 +1343,13 @@ void CodeGen::genCodeForIndir(GenTreeIndir* tree)
 
     if (tree->gtFlags & GTF_IND_VOLATILE)
     {
+#ifdef _TARGET_ARM64_
+        // issue a INS_BARRIER_LD after a volatile LdInd operation
+        instGen_MemoryBarrier(INS_BARRIER_LD);
+#else
         // issue a full memory barrier after a volatile LdInd operation
         instGen_MemoryBarrier();
+#endif // _TARGET_ARM64_
     }
 }
 
@@ -1370,7 +1375,7 @@ void CodeGen::genCodeForCpBlk(GenTreeBlk* cpBlkNode)
 
     if (cpBlkNode->gtFlags & GTF_BLK_VOLATILE)
     {
-        // issue a full memory barrier before & after a volatile CpBlkUnroll operation
+        // issue a full memory barrier before a volatile CpBlk operation
         instGen_MemoryBarrier();
     }
 
@@ -1378,8 +1383,13 @@ void CodeGen::genCodeForCpBlk(GenTreeBlk* cpBlkNode)
 
     if (cpBlkNode->gtFlags & GTF_BLK_VOLATILE)
     {
-        // issue a full memory barrier before & after a volatile CpBlkUnroll operation
+#ifdef _TARGET_ARM64_
+        // issue a INS_BARRIER_LD after a volatile CpBlk operation
+        instGen_MemoryBarrier(INS_BARRIER_LD);
+#else
+        // issue a full memory barrier after a volatile CpBlk operation
         instGen_MemoryBarrier();
+#endif // _TARGET_ARM64_
     }
 }
 
diff --git a/src/jit/instr.cpp b/src/jit/instr.cpp
index bbfca1d7e8..4d30fdea1c 100644
--- a/src/jit/instr.cpp
+++ b/src/jit/instr.cpp
@@ -3852,7 +3852,11 @@ void CodeGen::instGen_Return(unsigned stkArgSize)
  *     Note: all MemoryBarriers instructions can be removed by
  *           SET COMPlus_JitNoMemoryBarriers=1
  */
+#ifdef _TARGET_ARM64_
+void CodeGen::instGen_MemoryBarrier(insBarrier barrierType)
+#else
 void CodeGen::instGen_MemoryBarrier()
+#endif
 {
 #ifdef DEBUG
     if (JitConfig.JitNoMemoryBarriers() == 1)
@@ -3867,7 +3871,7 @@ void CodeGen::instGen_MemoryBarrier()
 #elif defined(_TARGET_ARM_)
     getEmitter()->emitIns_I(INS_dmb, EA_4BYTE, 0xf);
 #elif defined(_TARGET_ARM64_)
-    getEmitter()->emitIns_BARR(INS_dmb, INS_BARRIER_SY);
+    getEmitter()->emitIns_BARR(INS_dmb, barrierType);
 #else
 #error "Unknown _TARGET_"
 #endif