Interpreter & JIT support for write barriers

In this iteration, cards are marked on either the store address or
the object head (whichever leads to faster code).  In all cases,
though, card marks are deferred until after the associated store
has completed.

Change-Id: I633d6e8c3bebdb80bde92efb4fa6fc7cc84f60fc

1 files changed, 42 insertions, 6 deletions

diff --git a/vm/compiler/codegen/arm/CodegenDriver.c b/vm/compiler/codegen/arm/CodegenDriver.c
index 03fc2af0f..d69991d5d 100644
--- a/vm/compiler/codegen/arm/CodegenDriver.c
+++ b/vm/compiler/codegen/arm/CodegenDriver.c
@@ -24,6 +24,25 @@
  * applicable directory below this one.
  */
 
+/*
+ * Mark garbage collection card. Skip if the value we're storing is null.
+ */
+static void markCard(CompilationUnit *cUnit, int valReg, int tgtAddrReg)
+{
+    int regCardBase = dvmCompilerAllocTemp(cUnit);
+    int regCardNo = dvmCompilerAllocTemp(cUnit);
+    opRegImm(cUnit, kOpCmp, valReg, 0); /* storing null? */
+    ArmLIR *branchOver = opCondBranch(cUnit, kArmCondEq);
+    loadWordDisp(cUnit, rGLUE, offsetof(InterpState, cardTable),
+                 regCardBase);
+    opRegRegImm(cUnit, kOpLsr, regCardNo, tgtAddrReg, GC_CARD_SHIFT);
+    storeBaseIndexed(cUnit, regCardBase, regCardNo, regCardBase, 0,
+                     kUnsignedByte);
+    ArmLIR *target = newLIR0(cUnit, kArmPseudoTargetLabel);
+    target->defMask = ENCODE_ALL;
+    branchOver->generic.target = (LIR *)target;
+}
+
 static bool genConversionCall(CompilationUnit *cUnit, MIR *mir, void *funct,
                                      int srcSize, int tgtSize)
 {
@@ -306,7 +325,7 @@ static void genIGet(CompilationUnit *cUnit, MIR *mir, OpSize size,
  *
  */
 static void genIPut(CompilationUnit *cUnit, MIR *mir, OpSize size,
-                    int fieldOffset)
+                    int fieldOffset, bool isObject)
 {
     RegisterClass regClass = dvmCompilerRegClassBySize(size);
     RegLocation rlSrc = dvmCompilerGetSrc(cUnit, mir, 0);
@@ -319,6 +338,10 @@ static void genIPut(CompilationUnit *cUnit, MIR *mir, OpSize size,
     HEAP_ACCESS_SHADOW(true);
     storeBaseDisp(cUnit, rlObj.lowReg, fieldOffset, rlSrc.lowReg, size);
     HEAP_ACCESS_SHADOW(false);
+    if (isObject) {
+        /* NOTE: marking card based on object head */
+        markCard(cUnit, rlSrc.lowReg, rlObj.lowReg);
+    }
 }
 
 
@@ -528,12 +551,14 @@ static void genArrayObjectPut(CompilationUnit *cUnit, MIR *mir,
     dvmCompilerLockTemp(cUnit, regPtr);   // r4PC
     dvmCompilerLockTemp(cUnit, regIndex); // r7
     dvmCompilerLockTemp(cUnit, r0);
+    dvmCompilerLockTemp(cUnit, r1);
 
     /* Bad? - roll back and re-execute if so */
     genRegImmCheck(cUnit, kArmCondEq, r0, 0, mir->offset, pcrLabel);
 
-    /* Resume here - must reload element, regPtr & index preserved */
+    /* Resume here - must reload element & array, regPtr & index preserved */
     loadValueDirectFixed(cUnit, rlSrc, r0);
+    loadValueDirectFixed(cUnit, rlArray, r1);
 
     ArmLIR *target = newLIR0(cUnit, kArmPseudoTargetLabel);
     target->defMask = ENCODE_ALL;
@@ -543,6 +568,9 @@ static void genArrayObjectPut(CompilationUnit *cUnit, MIR *mir,
     storeBaseIndexed(cUnit, regPtr, regIndex, r0,
                      scale, kWord);
     HEAP_ACCESS_SHADOW(false);
+
+    /* NOTE: marking card here based on object head */
+    markCard(cUnit, r0, r1);
 }
 
 static bool genShiftOpLong(CompilationUnit *cUnit, MIR *mir,
@@ -1488,6 +1516,10 @@ static bool handleFmt21c_Fmt31c(CompilationUnit *cUnit, MIR *mir)
             HEAP_ACCESS_SHADOW(true);
             storeWordDisp(cUnit, tReg, 0 ,rlSrc.lowReg);
             HEAP_ACCESS_SHADOW(false);
+            if (mir->dalvikInsn.opCode == OP_SPUT_OBJECT) {
+                /* NOTE: marking card based on field address */
+                markCard(cUnit, rlSrc.lowReg, tReg);
+            }
 
             break;
         }
@@ -2218,16 +2250,18 @@ static bool handleFmt22c(CompilationUnit *cUnit, MIR *mir)
             genIPutWide(cUnit, mir, fieldOffset);
             break;
         case OP_IPUT:
+            genIPut(cUnit, mir, kWord, fieldOffset, false);
+            break;
         case OP_IPUT_OBJECT:
-            genIPut(cUnit, mir, kWord, fieldOffset);
+            genIPut(cUnit, mir, kWord, fieldOffset, true);
             break;
         case OP_IPUT_SHORT:
         case OP_IPUT_CHAR:
-            genIPut(cUnit, mir, kUnsignedHalf, fieldOffset);
+            genIPut(cUnit, mir, kUnsignedHalf, fieldOffset, false);
             break;
         case OP_IPUT_BYTE:
         case OP_IPUT_BOOLEAN:
-            genIPut(cUnit, mir, kUnsignedByte, fieldOffset);
+            genIPut(cUnit, mir, kUnsignedByte, fieldOffset, false);
             break;
         case OP_IGET_WIDE_VOLATILE:
         case OP_IPUT_WIDE_VOLATILE:
@@ -2251,8 +2285,10 @@ static bool handleFmt22cs(CompilationUnit *cUnit, MIR *mir)
             genIGet(cUnit, mir, kWord, fieldOffset);
             break;
         case OP_IPUT_QUICK:
+            genIPut(cUnit, mir, kWord, fieldOffset, false);
+            break;
         case OP_IPUT_OBJECT_QUICK:
-            genIPut(cUnit, mir, kWord, fieldOffset);
+            genIPut(cUnit, mir, kWord, fieldOffset, true);
             break;
         case OP_IGET_WIDE_QUICK:
             genIGetWide(cUnit, mir, fieldOffset);