[turbofan] Frame elision for code stubs

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

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/ast/scopes.h"
 #include "src/compiler/code-generator.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/osr.h"
@@ skipping 206 matching lines @@
  public:
   OutOfLineRecordWrite(CodeGenerator* gen, Register object, Register index,
                        Register value, Register scratch0, Register scratch1,
                        RecordWriteMode mode)
       : OutOfLineCode(gen),
         object_(object),
         index_(index),
         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) {
       __ JumpIfSmi(value_, exit());
     }
     __ CheckPageFlag(value_, scratch0_,
                      MemoryChunk::kPointersToHereAreInterestingMask, eq,
                      exit());
     RememberedSetAction const remembered_set_action =
         mode_ > RecordWriteMode::kValueIsMap ? EMIT_REMEMBERED_SET
                                              : 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);
     }
     RecordWriteStub stub(isolate(), object_, scratch0_, scratch1_,
                          remembered_set_action, save_fp_mode);
     __ Addu(scratch1_, object_, index_);
     __ CallStub(&stub);
-    if (!frame()->needs_frame()) {
+    if (must_save_lr_) {
       __ Pop(ra);
     }
   }
 
  private:
   Register const object_;
   Register const index_;
   Register const value_;
   Register const scratch0_;
   Register const scratch1_;
   RecordWriteMode const mode_;
+  bool must_save_lr_;
 };
 
 
 Condition FlagsConditionToConditionCmp(FlagsCondition condition) {
   switch (condition) {
     case kEqual:
       return eq;
     case kNotEqual:
       return ne;
     case kSignedLessThan:
@@ skipping 192 matching lines @@
               Operand(kFloat32ExponentBias + kFloat32MantissaBits));          \
     __ mov_s(i.OutputDoubleRegister(), i.InputDoubleRegister(0));             \
     __ mode##_w_s(i.OutputDoubleRegister(), i.InputDoubleRegister(0));        \
     __ mfc1(at, i.OutputDoubleRegister());                                    \
     __ Branch(USE_DELAY_SLOT, ool->entry(), eq, at, Operand(zero_reg));       \
     __ cvt_s_w(i.OutputDoubleRegister(), i.OutputDoubleRegister());           \
     __ bind(ool->exit());                                                     \
     __ 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) {
     __ addiu(sp, sp, sp_slot_delta * kPointerSize);
   }
   frame_access_state()->SetFrameAccessToDefault();
 }
 
 
 void CodeGenerator::AssemblePrepareTailCall(int stack_param_delta) {
   int sp_slot_delta = TailCallFrameStackSlotDelta(stack_param_delta);
   if (sp_slot_delta < 0) {
     __ Subu(sp, sp, Operand(-sp_slot_delta * kPointerSize));
     frame_access_state()->IncreaseSPDelta(-sp_slot_delta);
   }
-  if (frame()->needs_frame()) {
+  if (frame_access_state()->has_frame()) {
     __ lw(ra, MemOperand(fp, StandardFrameConstants::kCallerPCOffset));
     __ lw(fp, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
   }
   frame_access_state()->SetFrameAccessToSP();
 }
 
 void CodeGenerator::AssemblePopArgumentsAdaptorFrame(Register args_reg,
                                                      Register scratch1,
                                                      Register scratch2,
                                                      Register scratch3) {
@@ skipping 139 matching lines @@
     case kArchRet:
       AssembleReturn();
       break;
     case kArchStackPointer:
       __ mov(i.OutputRegister(), sp);
       break;
     case kArchFramePointer:
       __ mov(i.OutputRegister(), fp);
       break;
     case kArchParentFramePointer:
-      if (frame_access_state()->frame()->needs_frame()) {
+      if (frame_access_state()->has_frame()) {
         __ lw(i.OutputRegister(), MemOperand(fp, 0));
       } else {
         __ mov(i.OutputRegister(), fp);
       }
       break;
     case kArchTruncateDoubleToI:
       __ TruncateDoubleToI(i.OutputRegister(), i.InputDoubleRegister(0));
       break;
     case kArchStoreWithWriteBarrier: {
       RecordWriteMode mode =
@@ skipping 629 matching lines @@
       return true;
     default:
       break;
   }
   return false;
 }
 
 
 // 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;
   Condition cc = kNoCondition;
   // MIPS does not have condition code flags, so compare and branch are
   // implemented differently than on the other arch's. The compare operations
   // emit mips pseudo-instructions, which are handled here by branch
   // instructions that do the actual comparison. Essential that the input
   // registers to compare pseudo-op are not modified before this branch op, as
   // they are tested here.
@@ skipping 58 matching lines @@
   } else {
     PrintF("AssembleArchBranch Unimplemented arch_opcode: %d\n",
            instr->arch_opcode());
     UNIMPLEMENTED();
   }
   if (!branch->fallthru) __ Branch(flabel);  // no fallthru to flabel.
 }
 
 
 void CodeGenerator::AssembleArchJump(RpoNumber target) {
+  AssembleDeconstructFrameIfNeeded();
   if (!IsNextInAssemblyOrder(target)) __ Branch(GetLabel(target));
 }
 
 
 // Assembles boolean materializations after an instruction.
 void CodeGenerator::AssembleArchBoolean(Instruction* instr,
                                         FlagsCondition condition) {
   MipsOperandConverter i(this, instr);
   Label done;
 
@@ skipping 171 matching lines @@
     int deoptimization_id, Deoptimizer::BailoutType bailout_type) {
   Address deopt_entry = Deoptimizer::GetDeoptimizationEntry(
       isolate(), deoptimization_id, bailout_type);
   __ Call(deopt_entry, RelocInfo::RUNTIME_ENTRY);
 }
 
 
 void CodeGenerator::AssemblePrologue() {
   CallDescriptor* descriptor = linkage()->GetIncomingDescriptor();
   int stack_shrink_slots = frame()->GetSpillSlotCount();
-  if (frame()->needs_frame()) {
+  if (frame_access_state()->has_frame()) {
     if (descriptor->IsCFunctionCall()) {
       __ Push(ra, fp);
       __ mov(fp, sp);
     } else if (descriptor->IsJSFunctionCall()) {
       __ Prologue(this->info()->GeneratePreagedPrologue());
     } else {
       __ StubPrologue(info()->GetOutputStackFrameType());
     }
-  } else {
-    frame()->SetElidedFrameSizeInSlots(0);
   }
-  frame_access_state()->SetFrameAccessToDefault();
 
   if (info()->is_osr()) {
     // TurboFan OSR-compiled functions cannot be entered directly.
     __ Abort(kShouldNotDirectlyEnterOsrFunction);
 
     // Unoptimized code jumps directly to this entrypoint while the unoptimized
     // frame is still on the stack. Optimized code uses OSR values directly from
     // the unoptimized frame. Thus, all that needs to be done is to allocate the
     // remaining stack slots.
     if (FLAG_code_comments) __ RecordComment("-- OSR entrypoint --");
@@ skipping 41 matching lines @@
     __ MultiPop(saves);
   }
 
   // Restore FPU registers.
   const RegList saves_fpu = descriptor->CalleeSavedFPRegisters();
   if (saves_fpu != 0) {
     __ MultiPopFPU(saves_fpu);
   }
 
   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;
   }
   if (pop_count != 0) {
     __ DropAndRet(pop_count);
   } else {
     __ Ret();
   }
 }
 
 
 void CodeGenerator::AssembleMove(InstructionOperand* source,
@@ skipping 202 matching lines @@
       padding_size -= v8::internal::Assembler::kInstrSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8