[turbofan] Avoid unnecessary write barriers and improve code generation.

src/compiler/arm/instruction-selector-arm.cc

Index: src/compiler/arm/instruction-selector-arm.cc
diff --git a/src/compiler/arm/instruction-selector-arm.cc b/src/compiler/arm/instruction-selector-arm.cc
index 18b392b6753dd08b87f5cd51ee30a7545e563bb5..aa98e1663905809720316e09a2c715f1c29fd350 100644
--- a/src/compiler/arm/instruction-selector-arm.cc
+++ b/src/compiler/arm/instruction-selector-arm.cc
@@ -61,7 +61,6 @@ class ArmOperandGenerator : public OperandGenerator {
       case kArmStrb:
       case kArmLdr:
       case kArmStr:
-      case kArmStoreWriteBarrier:
         return value >= -4095 && value <= 4095;
 
       case kArmLdrh:
@@ -351,18 +350,8 @@ void InstructionSelector::VisitStore(Node* node) {
   Node* value = node->InputAt(2);
 
   StoreRepresentation store_rep = OpParameter<StoreRepresentation>(node);
+  WriteBarrierKind write_barrier_kind = store_rep.write_barrier_kind();
   MachineType rep = RepresentationOf(store_rep.machine_type());
-  if (store_rep.write_barrier_kind() == kFullWriteBarrier) {
-    DCHECK(rep == kRepTagged);
-    // TODO(dcarney): refactor RecordWrite function to take temp registers
-    //                and pass them here instead of using fixed regs
-    // TODO(dcarney): handle immediate indices.
-    InstructionOperand temps[] = {g.TempRegister(r5), g.TempRegister(r6)};
-    Emit(kArmStoreWriteBarrier, g.NoOutput(), g.UseFixed(base, r4),
-         g.UseFixed(index, r5), g.UseFixed(value, r6), arraysize(temps), temps);
-    return;
-  }
-  DCHECK_EQ(kNoWriteBarrier, store_rep.write_barrier_kind());
 
   ArchOpcode opcode;
   switch (rep) {
@@ -395,6 +384,36 @@ void InstructionSelector::VisitStore(Node* node) {
     Emit(opcode | AddressingModeField::encode(kMode_Offset_RR), g.NoOutput(),
          g.UseRegister(base), g.UseRegister(index), g.UseRegister(value));
   }
+
+  if (write_barrier_kind != kNoWriteBarrier) {
+    DCHECK_EQ(kRepTagged, rep);
+    InstructionOperand inputs[3];
+    size_t input_count = 0;
+    inputs[input_count++] = g.UseUniqueRegister(base);
+    inputs[input_count++] = g.UseUniqueRegister(index);
+    RecordWriteMode record_write_mode;
+    switch (write_barrier_kind) {
+      case kNoWriteBarrier:
+        UNREACHABLE();
+        break;
+      case kMapWriteBarrier:
+        record_write_mode = RecordWriteMode::kValueIsMap;
+        break;
+      case kPointerWriteBarrier:
+        inputs[input_count++] = g.UseUniqueRegister(value);
+        record_write_mode = RecordWriteMode::kValueIsPointer;
+        break;
+      case kFullWriteBarrier:
+        inputs[input_count++] = g.UseUniqueRegister(value);
+        record_write_mode = RecordWriteMode::kValueIsAny;
+        break;
+    }
+    InstructionOperand temps[] = {g.TempRegister(), g.TempRegister()};
+    size_t const temp_count = arraysize(temps);
+    InstructionCode code = kArchRecordWrite;
+    code |= MiscField::encode(static_cast<int>(record_write_mode));
+    Emit(code, 0, nullptr, input_count, inputs, temp_count, temps);
+  }
 }