commit 12246b82eb9cdc621662a30b3c854d1abd307ec8
author buzbee <buzbee@google.com> Thu Sep 29 14:15:05 2011 -0700
committer buzbee <buzbee@google.com> Thu Sep 29 14:15:05 2011 -0700
tree 974ca2e66c6df38c149693fb0d700f7365d4f29a
parent 6181f79576e4269937b45e4fce8d0d004107e5b9

Add memory barriers (Issue 3338450)

Add missing barriers required for volatile access on Arm.  Also,
flipped long volatile field accesses to the slow path.  The
previous codegen was not only missing barriers, but was not
using 64-bit atomics.

Change-Id: I4aa2be2bf81971e5ae664c762ceaf2ea58ce231b

src/compiler/codegen/arm/Thumb2/Gen.cc

diff --git a/src/compiler/codegen/arm/Thumb2/Gen.cc b/src/compiler/codegen/arm/Thumb2/Gen.cc
index 5c83660..d81c200 100644
--- a/src/compiler/codegen/arm/Thumb2/Gen.cc
+++ b/src/compiler/codegen/arm/Thumb2/Gen.cc
@@ -500,9 +500,12 @@
         genNullCheck(cUnit, rlObj.sRegLow, rlObj.lowReg, mir);/* null obj? */
 
         if (isVolatile) {
-            oatGenMemBarrier(cUnit, kSY);
+            oatGenMemBarrier(cUnit, kST);
         }
         storeBaseDisp(cUnit, rlObj.lowReg, fieldOffset, rlSrc.lowReg, size);
+        if (isVolatile) {
+            oatGenMemBarrier(cUnit, kSY);
+        }
     }
     if (isObject) {
         /* NOTE: marking card based on object head */
@@ -513,10 +516,15 @@
 STATIC void genIGetWide(CompilationUnit* cUnit, MIR* mir, RegLocation rlDest,
                         RegLocation rlObj)
 {
+    RegLocation rlResult;
     Field* fieldPtr = cUnit->method->GetDeclaringClass()->GetDexCache()->
         GetResolvedField(mir->dalvikInsn.vC);
-    RegLocation rlResult;
-    if (fieldPtr == NULL) {
+#if ANDROID_SMP != 0
+    bool isVolatile = (fieldPtr == NULL) || fieldPtr->IsVolatile();
+#else
+    bool isVolatile = false;
+#endif
+    if ((fieldPtr == NULL) || isVolatile) {
         getFieldOffset(cUnit, mir);
         // Field offset in r0
         rlObj = loadValue(cUnit, rlObj, kCoreReg);
@@ -525,13 +533,8 @@
         opRegReg(cUnit, kOpAdd, r0, rlObj.lowReg);
         loadPair(cUnit, r0, rlResult.lowReg, rlResult.highReg);
         oatGenMemBarrier(cUnit, kSY);
-        storeValue(cUnit, rlDest, rlResult);
+        storeValueWide(cUnit, rlDest, rlResult);
     } else {
-#if ANDROID_SMP != 0
-        bool isVolatile = fieldPtr->IsVolatile();
-#else
-        bool isVolatile = false;
-#endif
         int fieldOffset = fieldPtr->GetOffset().Int32Value();
         rlObj = loadValue(cUnit, rlObj, kCoreReg);
         int regPtr = oatAllocTemp(cUnit);
@@ -544,10 +547,6 @@
 
         loadPair(cUnit, regPtr, rlResult.lowReg, rlResult.highReg);
 
-        if (isVolatile) {
-            oatGenMemBarrier(cUnit, kSY);
-        }
-
         oatFreeTemp(cUnit, regPtr);
         storeValueWide(cUnit, rlDest, rlResult);
     }
@@ -558,7 +557,12 @@
 {
     Field* fieldPtr = cUnit->method->GetDeclaringClass()->GetDexCache()->
         GetResolvedField(mir->dalvikInsn.vC);
-    if (fieldPtr == NULL) {
+#if ANDROID_SMP != 0
+    bool isVolatile = (fieldPtr == NULL) || fieldPtr->IsVolatile();
+#else
+    bool isVolatile = false;
+#endif
+    if ((fieldPtr == NULL) || isVolatile) {
         getFieldOffset(cUnit, mir);
         // Field offset in r0
         rlObj = loadValue(cUnit, rlObj, kCoreReg);
@@ -568,11 +572,6 @@
         oatGenMemBarrier(cUnit, kSY);
         storePair(cUnit, r0, rlSrc.lowReg, rlSrc.highReg);
     } else {
-#if ANDROID_SMP != 0
-        bool isVolatile = fieldPtr->IsVolatile();
-#else
-        bool isVolatile = false;
-#endif
         int fieldOffset = fieldPtr->GetOffset().Int32Value();
 
         rlObj = loadValue(cUnit, rlObj, kCoreReg);
@@ -582,9 +581,6 @@
         regPtr = oatAllocTemp(cUnit);
         opRegRegImm(cUnit, kOpAdd, regPtr, rlObj.lowReg, fieldOffset);
 
-        if (isVolatile) {
-            oatGenMemBarrier(cUnit, kSY);
-        }
         storePair(cUnit, regPtr, rlSrc.lowReg, rlSrc.highReg);
 
         oatFreeTemp(cUnit, regPtr);