text: // 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/assembler-inl.h"
  #include "src/deoptimizer.h"
  #include "src/register-configuration.h"
  #include "src/safepoint-table.h"
  
  namespace v8 {
  namespace internal {
  
  // LAY + LGHI/LHI + BRCL
  const int Deoptimizer::table_entry_size_ = 16;
  
  #define __ masm()->
  
  // This code tries to be close to ia32 code so that any changes can be
  // easily ported.
  void Deoptimizer::TableEntryGenerator::Generate() {
    GeneratePrologue();
  
    // Save all the registers onto the stack
    const int kNumberOfRegisters = Register::kNumRegisters;
  
    RegList restored_regs = kJSCallerSaved | kCalleeSaved;
  
    const int kDoubleRegsSize = kDoubleSize * DoubleRegister::kNumRegisters;
    const int kFloatRegsSize = kFloatSize * FloatRegister::kNumRegisters;
  
    // Save all double registers before messing with them.
    __ lay(sp, MemOperand(sp, -kDoubleRegsSize));
    const RegisterConfiguration* config = RegisterConfiguration::Default();
    for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
      int code = config->GetAllocatableDoubleCode(i);
      const DoubleRegister dreg = DoubleRegister::from_code(code);
      int offset = code * kDoubleSize;
      __ StoreDouble(dreg, MemOperand(sp, offset));
    }
    // Save all float registers before messing with them.
    __ lay(sp, MemOperand(sp, -kFloatRegsSize));
    for (int i = 0; i < config->num_allocatable_float_registers(); ++i) {
      int code = config->GetAllocatableFloatCode(i);
      const FloatRegister dreg = FloatRegister::from_code(code);
      int offset = code * kFloatSize;
      __ StoreFloat32(dreg, MemOperand(sp, offset));
    }
  
    // Push all GPRs onto the stack
    __ lay(sp, MemOperand(sp, -kNumberOfRegisters * kPointerSize));
    __ StoreMultipleP(r0, sp, MemOperand(sp));  // Save all 16 registers
  
    __ mov(ip, Operand(ExternalReference::Create(
                   IsolateAddressId::kCEntryFPAddress, isolate())));
    __ StoreP(fp, MemOperand(ip));
  
    const int kSavedRegistersAreaSize =
        (kNumberOfRegisters * kPointerSize) + kDoubleRegsSize + kFloatRegsSize;
  
    // Get the bailout id from the stack.
    __ LoadP(r4, MemOperand(sp, kSavedRegistersAreaSize));
  
    // Cleanse the Return address for 31-bit
    __ CleanseP(r14);
  
    // Get the address of the location in the code object (r5)(return
    // address for lazy deoptimization) and compute the fp-to-sp delta in
    // register r6.
    __ LoadRR(r5, r14);
    __ la(r6, MemOperand(sp, kSavedRegistersAreaSize + (1 * kPointerSize)));
    __ SubP(r6, fp, r6);
  
    // Allocate a new deoptimizer object.
    // Pass six arguments in r2 to r7.
    __ PrepareCallCFunction(6, r7);
    __ LoadImmP(r2, Operand::Zero());
    Label context_check;
    __ LoadP(r3, MemOperand(fp, CommonFrameConstants::kContextOrFrameTypeOffset));
    __ JumpIfSmi(r3, &context_check);
    __ LoadP(r2, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
    __ bind(&context_check);
    __ LoadImmP(r3, Operand(static_cast<int>(deopt_kind())));
    // r4: bailout id already loaded.
    // r5: code address or 0 already loaded.
    // r6: Fp-to-sp delta.
    // Parm6: isolate is passed on the stack.
    __ mov(r7, Operand(ExternalReference::isolate_address(isolate())));
    __ StoreP(r7, MemOperand(sp, kStackFrameExtraParamSlot * kPointerSize));
  
    // Call Deoptimizer::New().
    {
      AllowExternalCallThatCantCauseGC scope(masm());
      __ CallCFunction(ExternalReference::new_deoptimizer_function(), 6);
    }
  
    // Preserve "deoptimizer" object in register r2 and get the input
    // frame descriptor pointer to r3 (deoptimizer->input_);
    __ LoadP(r3, MemOperand(r2, Deoptimizer::input_offset()));
  
    // Copy core registers into FrameDescription::registers_[kNumRegisters].
    // DCHECK_EQ(Register::kNumRegisters, kNumberOfRegisters);
    // __ mvc(MemOperand(r3, FrameDescription::registers_offset()),
    //        MemOperand(sp), kNumberOfRegisters * kPointerSize);
    // Copy core registers into FrameDescription::registers_[kNumRegisters].
    // TODO(john.yan): optimize the following code by using mvc instruction
    DCHECK_EQ(Register::kNumRegisters, kNumberOfRegisters);
    for (int i = 0; i < kNumberOfRegisters; i++) {
      int offset = (i * kPointerSize) + FrameDescription::registers_offset();
      __ LoadP(r4, MemOperand(sp, i * kPointerSize));
      __ StoreP(r4, MemOperand(r3, offset));
    }
  
    int double_regs_offset = FrameDescription::double_registers_offset();
    // Copy double registers to
    // double_registers_[DoubleRegister::kNumRegisters]
    for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
      int code = config->GetAllocatableDoubleCode(i);
      int dst_offset = code * kDoubleSize + double_regs_offset;
      int src_offset =
          code * kDoubleSize + kNumberOfRegisters * kPointerSize + kFloatRegsSize;
      // TODO(joransiu): MVC opportunity
      __ LoadDouble(d0, MemOperand(sp, src_offset));
      __ StoreDouble(d0, MemOperand(r3, dst_offset));
    }
  
    int float_regs_offset = FrameDescription::float_registers_offset();
    // Copy float registers to
    // float_registers_[FloatRegister::kNumRegisters]
    for (int i = 0; i < config->num_allocatable_float_registers(); ++i) {
      int code = config->GetAllocatableFloatCode(i);
      int dst_offset = code * kFloatSize + float_regs_offset;
      int src_offset = code * kFloatSize + kNumberOfRegisters * kPointerSize;
      // TODO(joransiu): MVC opportunity
      __ LoadFloat32(d0, MemOperand(sp, src_offset));
      __ StoreFloat32(d0, MemOperand(r3, dst_offset));
    }
    // Remove the bailout id and the saved registers from the stack.
    __ la(sp, MemOperand(sp, kSavedRegistersAreaSize + (1 * kPointerSize)));
  
    // Compute a pointer to the unwinding limit in register r4; that is
    // the first stack slot not part of the input frame.
    __ LoadP(r4, MemOperand(r3, FrameDescription::frame_size_offset()));
    __ AddP(r4, sp);
  
    // Unwind the stack down to - but not including - the unwinding
    // limit and copy the contents of the activation frame to the input
    // frame description.
    __ la(r5, MemOperand(r3, FrameDescription::frame_content_offset()));
    Label pop_loop;
    Label pop_loop_header;
    __ b(&pop_loop_header, Label::kNear);
    __ bind(&pop_loop);
    __ pop(r6);
    __ StoreP(r6, MemOperand(r5, 0));
    __ la(r5, MemOperand(r5, kPointerSize));
    __ bind(&pop_loop_header);
    __ CmpP(r4, sp);
    __ bne(&pop_loop);
  
    // Compute the output frame in the deoptimizer.
    __ push(r2);  // Preserve deoptimizer object across call.
    // r2: deoptimizer object; r3: scratch.
    __ PrepareCallCFunction(1, r3);
    // Call Deoptimizer::ComputeOutputFrames().
    {
      AllowExternalCallThatCantCauseGC scope(masm());
      __ CallCFunction(ExternalReference::compute_output_frames_function(), 1);
    }
    __ pop(r2);  // Restore deoptimizer object (class Deoptimizer).
  
    __ LoadP(sp, MemOperand(r2, Deoptimizer::caller_frame_top_offset()));
  
    // Replace the current (input) frame with the output frames.
    Label outer_push_loop, inner_push_loop, outer_loop_header, inner_loop_header;
    // Outer loop state: r6 = current "FrameDescription** output_",
    // r3 = one past the last FrameDescription**.
    __ LoadlW(r3, MemOperand(r2, Deoptimizer::output_count_offset()));
    __ LoadP(r6, MemOperand(r2, Deoptimizer::output_offset()));  // r6 is output_.
    __ ShiftLeftP(r3, r3, Operand(kPointerSizeLog2));
    __ AddP(r3, r6, r3);
    __ b(&outer_loop_header, Label::kNear);
  
    __ bind(&outer_push_loop);
    // Inner loop state: r4 = current FrameDescription*, r5 = loop index.
    __ LoadP(r4, MemOperand(r6, 0));  // output_[ix]
    __ LoadP(r5, MemOperand(r4, FrameDescription::frame_size_offset()));
    __ b(&inner_loop_header, Label::kNear);
  
    __ bind(&inner_push_loop);
    __ AddP(r5, Operand(-sizeof(intptr_t)));
    __ AddP(r8, r4, r5);
    __ LoadP(r8, MemOperand(r8, FrameDescription::frame_content_offset()));
    __ push(r8);
  
    __ bind(&inner_loop_header);
    __ CmpP(r5, Operand::Zero());
    __ bne(&inner_push_loop);  // test for gt?
  
    __ AddP(r6, r6, Operand(kPointerSize));
    __ bind(&outer_loop_header);
    __ CmpP(r6, r3);
    __ blt(&outer_push_loop);
  
    __ LoadP(r3, MemOperand(r2, Deoptimizer::input_offset()));
    for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
      int code = config->GetAllocatableDoubleCode(i);
      const DoubleRegister dreg = DoubleRegister::from_code(code);
      int src_offset = code * kDoubleSize + double_regs_offset;
      __ ld(dreg, MemOperand(r3, src_offset));
    }
  
    // Push pc and continuation from the last output frame.
    __ LoadP(r8, MemOperand(r4, FrameDescription::pc_offset()));
    __ push(r8);
    __ LoadP(r8, MemOperand(r4, FrameDescription::continuation_offset()));
    __ push(r8);
  
    // Restore the registers from the last output frame.
    __ LoadRR(r1, r4);
    for (int i = kNumberOfRegisters - 1; i > 0; i--) {
      int offset = (i * kPointerSize) + FrameDescription::registers_offset();
      if ((restored_regs & (1 << i)) != 0) {
        __ LoadP(ToRegister(i), MemOperand(r1, offset));
      }
    }
  
    __ InitializeRootRegister();
  
    __ pop(ip);  // get continuation, leave pc on stack
    __ pop(r14);
    __ Jump(ip);
    __ stop("Unreachable.");
  }
  
  void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
    // Create a sequence of deoptimization entries. Note that any
    // registers may be still live.
    Label done;
    for (int i = 0; i < count(); i++) {
      int start = masm()->pc_offset();
      USE(start);
      __ lay(sp, MemOperand(sp, -kPointerSize));
      __ LoadImmP(ip, Operand(i));
      __ b(&done);
      int end = masm()->pc_offset();
      USE(end);
      DCHECK(masm()->pc_offset() - start == table_entry_size_);
    }
    __ bind(&done);
    __ StoreP(ip, MemOperand(sp));
  }
  
  bool Deoptimizer::PadTopOfStackRegister() { return false; }
  
  void FrameDescription::SetCallerPc(unsigned offset, intptr_t value) {
    SetFrameSlot(offset, value);
  }
  
  void FrameDescription::SetCallerFp(unsigned offset, intptr_t value) {
    SetFrameSlot(offset, value);
  }
  
  void FrameDescription::SetCallerConstantPool(unsigned offset, intptr_t value) {
    // No out-of-line constant pool support.
    UNREACHABLE();
  }
  
  #undef __
  
  }  // namespace internal
  }  // namespace v8
  