commit 919eb063ce4542d3698e10e20aba9a2dfbdd0f82
author buzbee <buzbee@google.com> Mon Jul 12 12:59:22 2010 -0700
committer buzbee <buzbee@google.com> Tue Jul 13 13:14:28 2010 -0700
tree 172e3da067f45323c1ef3f206abf5d4e80f594ff
parent d2f3ff738190d5b8d8f7ea288abc921fa9c26555

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

vm/compiler/codegen/arm/CodegenDriver.c

diff --git a/vm/compiler/codegen/arm/CodegenDriver.c b/vm/compiler/codegen/arm/CodegenDriver.c
index 03fc2af..d69991d 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 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 @@
     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 @@
     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 @@
     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 @@
             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 @@
             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 @@
             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);