[turbofan] Frame elision for code stubs

src/compiler/mips64/code-generator-mips64.cc

Index: src/compiler/mips64/code-generator-mips64.cc
diff --git a/src/compiler/mips64/code-generator-mips64.cc b/src/compiler/mips64/code-generator-mips64.cc
index 225b99d092029e9f4622e75fc90ab4276ab3ba93..f06c9dafc678bf34b113855bb678d84025cbe7be 100644
--- a/src/compiler/mips64/code-generator-mips64.cc
+++ b/src/compiler/mips64/code-generator-mips64.cc
@@ -224,7 +224,8 @@ class OutOfLineRecordWrite final : public OutOfLineCode {
         value_(value),
         scratch0_(scratch0),
         scratch1_(scratch1),
-        mode_(mode) {}
+        mode_(mode),
+        must_save_lr_(gen->frame_access_state()->has_frame()) {}
 
   void Generate() final {
     if (mode_ > RecordWriteMode::kValueIsPointer) {
@@ -238,7 +239,7 @@ class OutOfLineRecordWrite final : public OutOfLineCode {
                                              : OMIT_REMEMBERED_SET;
     SaveFPRegsMode const save_fp_mode =
         frame()->DidAllocateDoubleRegisters() ? kSaveFPRegs : kDontSaveFPRegs;
-    if (!frame()->needs_frame()) {
+    if (must_save_lr_) {
       // We need to save and restore ra if the frame was elided.
       __ Push(ra);
     }
@@ -246,7 +247,7 @@ class OutOfLineRecordWrite final : public OutOfLineCode {
                          remembered_set_action, save_fp_mode);
     __ Daddu(scratch1_, object_, index_);
     __ CallStub(&stub);
-    if (!frame()->needs_frame()) {
+    if (must_save_lr_) {
       __ Pop(ra);
     }
   }
@@ -258,6 +259,7 @@ class OutOfLineRecordWrite final : public OutOfLineCode {
   Register const scratch0_;
   Register const scratch1_;
   RecordWriteMode const mode_;
+  bool must_save_lr_;
 };
 
 
@@ -482,6 +484,13 @@ FPUCondition FlagsConditionToConditionCmpFPU(bool& predicate,
     __ bind(&done);                                                           \
   }
 
+void CodeGenerator::AssembleDeconstructFrame() {
+  __ mov(sp, fp);
+  __ Pop(ra, fp);
+}
+
+void CodeGenerator::SetupStackPointer() {}
+
 void CodeGenerator::AssembleDeconstructActivationRecord(int stack_param_delta) {
   int sp_slot_delta = TailCallFrameStackSlotDelta(stack_param_delta);
   if (sp_slot_delta > 0) {
@@ -497,7 +506,7 @@ void CodeGenerator::AssemblePrepareTailCall(int stack_param_delta) {
     __ Dsubu(sp, sp, Operand(-sp_slot_delta * kPointerSize));
     frame_access_state()->IncreaseSPDelta(-sp_slot_delta);
   }
-  if (frame()->needs_frame()) {
+  if (frame_access_state()->has_frame()) {
     __ ld(ra, MemOperand(fp, StandardFrameConstants::kCallerPCOffset));
     __ ld(fp, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
   }
@@ -655,7 +664,7 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ mov(i.OutputRegister(), fp);
       break;
     case kArchParentFramePointer:
-      if (frame_access_state()->frame()->needs_frame()) {
+      if (frame_access_state()->has_frame()) {
         __ ld(i.OutputRegister(), MemOperand(fp, 0));
       } else {
         __ mov(i.OutputRegister(), fp);
@@ -1585,6 +1594,7 @@ static bool convertCondition(FlagsCondition condition, Condition& cc) {
 
 // Assembles branches after an instruction.
 void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
+  AssembleDeconstructFrameIfNeeded();
   MipsOperandConverter i(this, instr);
   Label* tlabel = branch->true_label;
   Label* flabel = branch->false_label;
@@ -1669,6 +1679,7 @@ void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
 
 
 void CodeGenerator::AssembleArchJump(RpoNumber target) {
+  AssembleDeconstructFrameIfNeeded();
   if (!IsNextInAssemblyOrder(target)) __ Branch(GetLabel(target));
 }
 
@@ -1870,7 +1881,7 @@ void CodeGenerator::AssembleDeoptimizerCall(
 
 void CodeGenerator::AssemblePrologue() {
   CallDescriptor* descriptor = linkage()->GetIncomingDescriptor();
-  if (frame()->needs_frame()) {
+  if (frame_access_state()->has_frame()) {
     if (descriptor->IsCFunctionCall()) {
       __ Push(ra, fp);
       __ mov(fp, sp);
@@ -1879,10 +1890,7 @@ void CodeGenerator::AssemblePrologue() {
     } else {
       __ StubPrologue(info()->GetOutputStackFrameType());
     }
-  } else {
-    frame()->SetElidedFrameSizeInSlots(0);
   }
-  frame_access_state()->SetFrameAccessToDefault();
 
   int stack_shrink_slots = frame()->GetSpillSlotCount();
   if (info()->is_osr()) {
@@ -1941,18 +1949,9 @@ void CodeGenerator::AssembleReturn() {
   }
 
   if (descriptor->IsCFunctionCall()) {
-    __ mov(sp, fp);
-    __ Pop(ra, fp);
-  } else if (frame()->needs_frame()) {
-    // Canonicalize JSFunction return sites for now.
-    if (return_label_.is_bound()) {
-      __ Branch(&return_label_);
-      return;
-    } else {
-      __ bind(&return_label_);
-      __ mov(sp, fp);
-      __ Pop(ra, fp);
-    }
+    AssembleDeconstructFrameIfNeeded();
+  } else if (frame_access_state()->has_frame()) {
+    if (AssembleDeconstructFrameUsingReturnLabel()) return;
   }
   int pop_count = static_cast<int>(descriptor->StackParameterCount());
   if (pop_count != 0) {