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

src/compiler/ppc/code-generator-ppc.cc

Index: src/compiler/ppc/code-generator-ppc.cc
diff --git a/src/compiler/ppc/code-generator-ppc.cc b/src/compiler/ppc/code-generator-ppc.cc
index dbc776ef9efbd3ee83060658eddd35211e328f90..fa973544be01613e00c54c393199cb2cc7c48a4c 100644
--- a/src/compiler/ppc/code-generator-ppc.cc
+++ b/src/compiler/ppc/code-generator-ppc.cc
@@ -157,6 +157,48 @@ class OutOfLineLoadZero final : public OutOfLineCode {
 };
 
 
+class OutOfLineRecordWrite final : public OutOfLineCode {
+ public:
+  OutOfLineRecordWrite(CodeGenerator* gen, Register object, Register offset,
+                       Register value, Register scratch0, Register scratch1,
+                       RecordWriteMode mode)
+      : OutOfLineCode(gen),
+        object_(object),
+        offset_(offset),
+        value_(value),
+        scratch0_(scratch0),
+        scratch1_(scratch1),
+        mode_(mode) {}
+
+  void Generate() final {
+    if (mode_ > RecordWriteMode::kValueIsPointer) {
+      __ JumpIfSmi(value_, exit());
+    }
+    if (mode_ > RecordWriteMode::kValueIsMap) {
+      __ CheckPageFlag(value_, scratch0_,
+                       MemoryChunk::kPointersToHereAreInterestingMask, eq,
+                       exit());
+    }
+    SaveFPRegsMode const save_fp_mode =
+        frame()->DidAllocateDoubleRegisters() ? kSaveFPRegs : kDontSaveFPRegs;
+    // TODO(turbofan): Once we get frame elision working, we need to save
+    // and restore lr properly here if the frame was elided.
+    RecordWriteStub stub(isolate(), object_, scratch0_, scratch1_,
+                         EMIT_REMEMBERED_SET, save_fp_mode);
+    __ add(scratch1_, object_, offset_);
+    __ CallStub(&stub);
+  }
+
+ private:
+  Register const object_;
+  Register const offset_;
+  Register const value_;
+  Register const scratch0_;
+  Register const scratch1_;
+  RecordWriteMode const mode_;
+};
+
+
 Condition FlagsConditionToCondition(FlagsCondition condition) {
   switch (condition) {
     case kEqual:
@@ -563,21 +605,6 @@ Condition FlagsConditionToCondition(FlagsCondition condition) {
   } while (0)
 
 
-#define ASSEMBLE_STORE_WRITE_BARRIER()                                         \
-  do {                                                                         \
-    Register object = i.InputRegister(0);                                      \
-    Register index = i.InputRegister(1);                                       \
-    Register value = i.InputRegister(2);                                       \
-    __ add(index, object, index);                                              \
-    __ StoreP(value, MemOperand(index));                                       \
-    SaveFPRegsMode mode =                                                      \
-        frame()->DidAllocateDoubleRegisters() ? kSaveFPRegs : kDontSaveFPRegs; \
-    LinkRegisterStatus lr_status = kLRHasNotBeenSaved;                         \
-    __ RecordWrite(object, index, value, lr_status, mode);                     \
-    DCHECK_EQ(LeaveRC, i.OutputRCBit());                                       \
-  } while (0)
-
-
 void CodeGenerator::AssembleDeconstructActivationRecord() {
   CallDescriptor* descriptor = linkage()->GetIncomingDescriptor();
   int stack_slots = frame()->GetSpillSlotCount();
@@ -714,6 +741,23 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ TruncateDoubleToI(i.OutputRegister(), i.InputDoubleRegister(0));
       DCHECK_EQ(LeaveRC, i.OutputRCBit());
       break;
+    case kArchStoreWithWriteBarrier: {
+      RecordWriteMode mode =
+          static_cast<RecordWriteMode>(MiscField::decode(instr->opcode()));
+      Register object = i.InputRegister(0);
+      Register offset = i.InputRegister(1);
+      Register value = i.InputRegister(2);
+      Register scratch0 = i.TempRegister(0);
+      Register scratch1 = i.TempRegister(1);
+      auto ool = new (zone()) OutOfLineRecordWrite(this, object, offset, value,
+                                                   scratch0, scratch1, mode);
+      __ StorePX(value, MemOperand(object, offset));
+      __ CheckPageFlag(object, scratch0,
+                       MemoryChunk::kPointersFromHereAreInterestingMask, ne,
+                       ool->entry());
+      __ bind(ool->exit());
+      break;
+    }
     case kPPC_And:
       if (HasRegisterInput(instr, 1)) {
         __ and_(i.OutputRegister(), i.InputRegister(0), i.InputRegister(1),
@@ -1155,9 +1199,6 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
     case kPPC_StoreDouble:
       ASSEMBLE_STORE_DOUBLE();
       break;
-    case kPPC_StoreWriteBarrier:
-      ASSEMBLE_STORE_WRITE_BARRIER();
-      break;
     case kCheckedLoadInt8:
       ASSEMBLE_CHECKED_LOAD_INTEGER(lbz, lbzx);
       __ extsb(i.OutputRegister(), i.OutputRegister());