baseline-compiler-arm64-inl.h

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// Copyright 2021 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.
 
#ifndef V8_BASELINE_ARM64_BASELINE_COMPILER_ARM64_INL_H_
#define V8_BASELINE_ARM64_BASELINE_COMPILER_ARM64_INL_H_
 
#include "src/baseline/baseline-compiler.h"
 
namespace v8 {
namespace internal {
namespace baseline {
 
#define __ basm_.
 
// A builtin call/jump mode that is used then short builtin calls feature is
// not enabled.
constexpr BuiltinCallJumpMode kFallbackBuiltinCallJumpModeForBaseline =
    BuiltinCallJumpMode::kIndirect;
 
void BaselineCompiler::Prologue() {
  ASM_CODE_COMMENT(&masm_);
  // Enter the frame here, since CallBuiltin will override lr.
  __ masm()->EnterFrame(StackFrame::BASELINE);
  DCHECK_EQ(kJSFunctionRegister, kJavaScriptCallTargetRegister);
  int max_frame_size = bytecode_->max_frame_size();
  CallBuiltin<Builtin::kBaselineOutOfLinePrologue>(
      kContextRegister, kJSFunctionRegister, kJavaScriptCallArgCountRegister,
      max_frame_size, kJavaScriptCallNewTargetRegister, bytecode_);
 
  __ masm()->AssertSpAligned();
  PrologueFillFrame();
  __ masm()->AssertSpAligned();
}
 
void BaselineCompiler::PrologueFillFrame() {
  ASM_CODE_COMMENT(&masm_);
  // Inlined register frame fill
  interpreter::Register new_target_or_generator_register =
      bytecode_->incoming_new_target_or_generator_register();
  if (v8_flags.debug_code) {
    __ masm()->CompareRoot(kInterpreterAccumulatorRegister,
                           RootIndex::kUndefinedValue);
    __ masm()->Assert(eq, AbortReason::kUnexpectedValue);
  }
  int register_count = bytecode_->register_count();
  // Magic value
  const int kLoopUnrollSize = 8;
  const int new_target_index = new_target_or_generator_register.index();
  const bool has_new_target = new_target_index != kMaxInt;
  if (has_new_target) {
      DCHECK_LE(new_target_index, register_count);
      int before_new_target_count = 0;
      for (; before_new_target_count + 2 <= new_target_index;
           before_new_target_count += 2) {
        __ masm()->Push(kInterpreterAccumulatorRegister,
                        kInterpreterAccumulatorRegister);
      }
      if (before_new_target_count == new_target_index) {
        __ masm()->Push(kJavaScriptCallNewTargetRegister,
                        kInterpreterAccumulatorRegister);
      } else {
        DCHECK_EQ(before_new_target_count + 1, new_target_index);
        __ masm()->Push(kInterpreterAccumulatorRegister,
                        kJavaScriptCallNewTargetRegister);
      }
      // We pushed before_new_target_count registers, plus the two registers
      // that included new_target.
      register_count -= (before_new_target_count + 2);
  }
  if (register_count < 2 * kLoopUnrollSize) {
    // If the frame is small enough, just unroll the frame fill completely.
    for (int i = 0; i < register_count; i += 2) {
      __ masm()->Push(kInterpreterAccumulatorRegister,
                      kInterpreterAccumulatorRegister);
    }
  } else {
    BaselineAssembler::ScratchRegisterScope temps(&basm_);
    Register scratch = temps.AcquireScratch();
 
    // Extract the first few registers to round to the unroll size.
    int first_registers = register_count % kLoopUnrollSize;
    for (int i = 0; i < first_registers; i += 2) {
      __ masm()->Push(kInterpreterAccumulatorRegister,
                      kInterpreterAccumulatorRegister);
    }
    __ Move(scratch, register_count / kLoopUnrollSize);
    // We enter the loop unconditionally, so make sure we need to loop at least
    // once.
    DCHECK_GT(register_count / kLoopUnrollSize, 0);
    Label loop;
    __ Bind(&loop);
    for (int i = 0; i < kLoopUnrollSize; i += 2) {
      __ masm()->Push(kInterpreterAccumulatorRegister,
                      kInterpreterAccumulatorRegister);
    }
    __ masm()->Subs(scratch, scratch, 1);
    __ masm()->B(gt, &loop);
  }
}
 
void BaselineCompiler::VerifyFrameSize() {
  ASM_CODE_COMMENT(&masm_);
  __ masm()->Add(x15, sp,
                 RoundUp(InterpreterFrameConstants::kFixedFrameSizeFromFp +
                             bytecode_->frame_size(),
                         2 * kSystemPointerSize));
  __ masm()->Cmp(x15, fp);
  __ masm()->Assert(eq, AbortReason::kUnexpectedStackPointer);
}
 
#undef __
 
}  // namespace baseline
}  // namespace internal
}  // namespace v8
 
#endif  // V8_BASELINE_ARM64_BASELINE_COMPILER_ARM64_INL_H_