src/arm/deoptimizer-arm.cc - external/v8 - Git at Google

 // Copyright 2012 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/v8.h"

 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen.h"
 #include "src/safepoint-table.h"

 namespace v8 {
 namespace internal {

 const int Deoptimizer::table_entry_size_ = 8;


 int Deoptimizer::patch_size() {
   const int kCallInstructionSizeInWords = 3;
   return kCallInstructionSizeInWords * Assembler::kInstrSize;
 }


 void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) {
   Address code_start_address = code->instruction_start();
   // Invalidate the relocation information, as it will become invalid by the
   // code patching below, and is not needed any more.
   code->InvalidateRelocation();

   if (FLAG_zap_code_space) {
     // Fail hard and early if we enter this code object again.
     byte* pointer = code->FindCodeAgeSequence();
     if (pointer != NULL) {
       pointer += kNoCodeAgeSequenceLength;
     } else {
       pointer = code->instruction_start();
     }
     CodePatcher patcher(pointer, 1);
     patcher.masm()->bkpt(0);

     DeoptimizationInputData* data =
         DeoptimizationInputData::cast(code->deoptimization_data());
     int osr_offset = data->OsrPcOffset()->value();
     if (osr_offset > 0) {
       CodePatcher osr_patcher(code->instruction_start() + osr_offset, 1);
       osr_patcher.masm()->bkpt(0);
     }
   }

   DeoptimizationInputData* deopt_data =
       DeoptimizationInputData::cast(code->deoptimization_data());
 #ifdef DEBUG
   Address prev_call_address = NULL;
 #endif
   // For each LLazyBailout instruction insert a call to the corresponding
   // deoptimization entry.
   for (int i = 0; i < deopt_data->DeoptCount(); i++) {
     if (deopt_data->Pc(i)->value() == -1) continue;
     Address call_address = code_start_address + deopt_data->Pc(i)->value();
     Address deopt_entry = GetDeoptimizationEntry(isolate, i, LAZY);
     // We need calls to have a predictable size in the unoptimized code, but
     // this is optimized code, so we don't have to have a predictable size.
     int call_size_in_bytes =
         MacroAssembler::CallSizeNotPredictableCodeSize(isolate,
                                                        deopt_entry,
                                                        RelocInfo::NONE32);
     int call_size_in_words = call_size_in_bytes / Assembler::kInstrSize;
     DCHECK(call_size_in_bytes % Assembler::kInstrSize == 0);
     DCHECK(call_size_in_bytes <= patch_size());
     CodePatcher patcher(call_address, call_size_in_words);
     patcher.masm()->Call(deopt_entry, RelocInfo::NONE32);
     DCHECK(prev_call_address == NULL ||
            call_address >= prev_call_address + patch_size());
     DCHECK(call_address + patch_size() <= code->instruction_end());
 #ifdef DEBUG
     prev_call_address = call_address;
 #endif
   }
 }


 void Deoptimizer::FillInputFrame(Address tos, JavaScriptFrame* frame) {
   // Set the register values. The values are not important as there are no
   // callee saved registers in JavaScript frames, so all registers are
   // spilled. Registers fp and sp are set to the correct values though.

   for (int i = 0; i < Register::kNumRegisters; i++) {
     input_->SetRegister(i, i * 4);
   }
   input_->SetRegister(sp.code(), reinterpret_cast<intptr_t>(frame->sp()));
   input_->SetRegister(fp.code(), reinterpret_cast<intptr_t>(frame->fp()));
   for (int i = 0; i < DoubleRegister::NumAllocatableRegisters(); i++) {
     input_->SetDoubleRegister(i, 0.0);
   }

   // Fill the frame content from the actual data on the frame.
   for (unsigned i = 0; i < input_->GetFrameSize(); i += kPointerSize) {
     input_->SetFrameSlot(i, Memory::uint32_at(tos + i));
   }
 }


 void Deoptimizer::SetPlatformCompiledStubRegisters(
     FrameDescription* output_frame, CodeStubDescriptor* descriptor) {
   ApiFunction function(descriptor->deoptimization_handler());
   ExternalReference xref(&function, ExternalReference::BUILTIN_CALL, isolate_);
   intptr_t handler = reinterpret_cast<intptr_t>(xref.address());
   int params = descriptor->GetHandlerParameterCount();
   output_frame->SetRegister(r0.code(), params);
   output_frame->SetRegister(r1.code(), handler);
 }


 void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
   for (int i = 0; i < DwVfpRegister::kMaxNumRegisters; ++i) {
     double double_value = input_->GetDoubleRegister(i);
     output_frame->SetDoubleRegister(i, double_value);
   }
 }


 bool Deoptimizer::HasAlignmentPadding(JSFunction* function) {
   // There is no dynamic alignment padding on ARM in the input frame.
   return false;
 }


 #define __ masm()->

 // This code tries to be close to ia32 code so that any changes can be
 // easily ported.
 void Deoptimizer::EntryGenerator::Generate() {
   GeneratePrologue();

   // Save all general purpose registers before messing with them.
   const int kNumberOfRegisters = Register::kNumRegisters;

   // Everything but pc, lr and ip which will be saved but not restored.
   RegList restored_regs = kJSCallerSaved | kCalleeSaved | ip.bit();

   const int kDoubleRegsSize =
       kDoubleSize * DwVfpRegister::kMaxNumAllocatableRegisters;

   // Save all allocatable VFP registers before messing with them.
   DCHECK(kDoubleRegZero.code() == 14);
   DCHECK(kScratchDoubleReg.code() == 15);

   // Check CPU flags for number of registers, setting the Z condition flag.
   __ CheckFor32DRegs(ip);

   // Push registers d0-d13, and possibly d16-d31, on the stack.
   // If d16-d31 are not pushed, decrease the stack pointer instead.
   __ vstm(db_w, sp, d16, d31, ne);
   __ sub(sp, sp, Operand(16 * kDoubleSize), LeaveCC, eq);
   __ vstm(db_w, sp, d0, d13);

   // Push all 16 registers (needed to populate FrameDescription::registers_).
   // TODO(1588) Note that using pc with stm is deprecated, so we should perhaps
   // handle this a bit differently.
   __ stm(db_w, sp, restored_regs  | sp.bit() | lr.bit() | pc.bit());

   const int kSavedRegistersAreaSize =
       (kNumberOfRegisters * kPointerSize) + kDoubleRegsSize;

   // Get the bailout id from the stack.
   __ ldr(r2, MemOperand(sp, kSavedRegistersAreaSize));

   // Get the address of the location in the code object (r3) (return
   // address for lazy deoptimization) and compute the fp-to-sp delta in
   // register r4.
   __ mov(r3, lr);
   // Correct one word for bailout id.
   __ add(r4, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
   __ sub(r4, fp, r4);

   // Allocate a new deoptimizer object.
   // Pass four arguments in r0 to r3 and fifth argument on stack.
   __ PrepareCallCFunction(6, r5);
   __ ldr(r0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
   __ mov(r1, Operand(type()));  // bailout type,
   // r2: bailout id already loaded.
   // r3: code address or 0 already loaded.
   __ str(r4, MemOperand(sp, 0 * kPointerSize));  // Fp-to-sp delta.
   __ mov(r5, Operand(ExternalReference::isolate_address(isolate())));
   __ str(r5, MemOperand(sp, 1 * kPointerSize));  // Isolate.
   // Call Deoptimizer::New().
   {
     AllowExternalCallThatCantCauseGC scope(masm());
     __ CallCFunction(ExternalReference::new_deoptimizer_function(isolate()), 6);
   }

   // Preserve "deoptimizer" object in register r0 and get the input
   // frame descriptor pointer to r1 (deoptimizer->input_);
   __ ldr(r1, MemOperand(r0, Deoptimizer::input_offset()));

   // Copy core registers into FrameDescription::registers_[kNumRegisters].
   DCHECK(Register::kNumRegisters == kNumberOfRegisters);
   for (int i = 0; i < kNumberOfRegisters; i++) {
     int offset = (i * kPointerSize) + FrameDescription::registers_offset();
     __ ldr(r2, MemOperand(sp, i * kPointerSize));
     __ str(r2, MemOperand(r1, offset));
   }

   // Copy VFP registers to
   // double_registers_[DoubleRegister::kMaxNumAllocatableRegisters]
   int double_regs_offset = FrameDescription::double_registers_offset();
   for (int i = 0; i < DwVfpRegister::kMaxNumAllocatableRegisters; ++i) {
     int dst_offset = i * kDoubleSize + double_regs_offset;
     int src_offset = i * kDoubleSize + kNumberOfRegisters * kPointerSize;
     __ vldr(d0, sp, src_offset);
     __ vstr(d0, r1, dst_offset);
   }

   // Remove the bailout id and the saved registers from the stack.
   __ add(sp, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));

   // Compute a pointer to the unwinding limit in register r2; that is
   // the first stack slot not part of the input frame.
   __ ldr(r2, MemOperand(r1, FrameDescription::frame_size_offset()));
   __ add(r2, r2, 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.
   __ add(r3,  r1, Operand(FrameDescription::frame_content_offset()));
   Label pop_loop;
   Label pop_loop_header;
   __ b(&pop_loop_header);
   __ bind(&pop_loop);
   __ pop(r4);
   __ str(r4, MemOperand(r3, 0));
   __ add(r3, r3, Operand(sizeof(uint32_t)));
   __ bind(&pop_loop_header);
   __ cmp(r2, sp);
   __ b(ne, &pop_loop);

   // Compute the output frame in the deoptimizer.
   __ push(r0);  // Preserve deoptimizer object across call.
   // r0: deoptimizer object; r1: scratch.
   __ PrepareCallCFunction(1, r1);
   // Call Deoptimizer::ComputeOutputFrames().
   {
     AllowExternalCallThatCantCauseGC scope(masm());
     __ CallCFunction(
         ExternalReference::compute_output_frames_function(isolate()), 1);
   }
   __ pop(r0);  // Restore deoptimizer object (class Deoptimizer).

   // 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: r4 = current "FrameDescription** output_",
   // r1 = one past the last FrameDescription**.
   __ ldr(r1, MemOperand(r0, Deoptimizer::output_count_offset()));
   __ ldr(r4, MemOperand(r0, Deoptimizer::output_offset()));  // r4 is output_.
   __ add(r1, r4, Operand(r1, LSL, 2));
   __ jmp(&outer_loop_header);
   __ bind(&outer_push_loop);
   // Inner loop state: r2 = current FrameDescription*, r3 = loop index.
   __ ldr(r2, MemOperand(r4, 0));  // output_[ix]
   __ ldr(r3, MemOperand(r2, FrameDescription::frame_size_offset()));
   __ jmp(&inner_loop_header);
   __ bind(&inner_push_loop);
   __ sub(r3, r3, Operand(sizeof(uint32_t)));
   __ add(r6, r2, Operand(r3));
   __ ldr(r6, MemOperand(r6, FrameDescription::frame_content_offset()));
   __ push(r6);
   __ bind(&inner_loop_header);
   __ cmp(r3, Operand::Zero());
   __ b(ne, &inner_push_loop);  // test for gt?
   __ add(r4, r4, Operand(kPointerSize));
   __ bind(&outer_loop_header);
   __ cmp(r4, r1);
   __ b(lt, &outer_push_loop);

   // Check CPU flags for number of registers, setting the Z condition flag.
   __ CheckFor32DRegs(ip);

   __ ldr(r1, MemOperand(r0, Deoptimizer::input_offset()));
   int src_offset = FrameDescription::double_registers_offset();
   for (int i = 0; i < DwVfpRegister::kMaxNumRegisters; ++i) {
     if (i == kDoubleRegZero.code()) continue;
     if (i == kScratchDoubleReg.code()) continue;

     const DwVfpRegister reg = DwVfpRegister::from_code(i);
     __ vldr(reg, r1, src_offset, i < 16 ? al : ne);
     src_offset += kDoubleSize;
   }

   // Push state, pc, and continuation from the last output frame.
   __ ldr(r6, MemOperand(r2, FrameDescription::state_offset()));
   __ push(r6);
   __ ldr(r6, MemOperand(r2, FrameDescription::pc_offset()));
   __ push(r6);
   __ ldr(r6, MemOperand(r2, FrameDescription::continuation_offset()));
   __ push(r6);

   // Push the registers from the last output frame.
   for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
     int offset = (i * kPointerSize) + FrameDescription::registers_offset();
     __ ldr(r6, MemOperand(r2, offset));
     __ push(r6);
   }

   // Restore the registers from the stack.
   __ ldm(ia_w, sp, restored_regs);  // all but pc registers.
   __ pop(ip);  // remove sp
   __ pop(ip);  // remove lr

   __ InitializeRootRegister();

   __ pop(ip);  // remove pc
   __ pop(ip);  // get continuation, leave pc on stack
   __ pop(lr);
   __ Jump(ip);
   __ stop("Unreachable.");
 }


 void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
   // Create a sequence of deoptimization entries.
   // Note that registers are still live when jumping to an entry.
   Label done;
   for (int i = 0; i < count(); i++) {
     int start = masm()->pc_offset();
     USE(start);
     __ mov(ip, Operand(i));
     __ b(&done);
     DCHECK(masm()->pc_offset() - start == table_entry_size_);
   }
   __ bind(&done);
   __ push(ip);
 }


 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) {
   DCHECK(FLAG_enable_ool_constant_pool);
   SetFrameSlot(offset, value);
 }


 #undef __

 } }  // namespace v8::internal
	// Copyright 2012 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/v8.h"

	#include "src/codegen.h"
	#include "src/deoptimizer.h"
	#include "src/full-codegen.h"
	#include "src/safepoint-table.h"

	namespace v8 {
	namespace internal {

	const int Deoptimizer::table_entry_size_ = 8;


	int Deoptimizer::patch_size() {
	const int kCallInstructionSizeInWords = 3;
	return kCallInstructionSizeInWords * Assembler::kInstrSize;
	}


	void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) {
	Address code_start_address = code->instruction_start();
	// Invalidate the relocation information, as it will become invalid by the
	// code patching below, and is not needed any more.
	code->InvalidateRelocation();

	if (FLAG_zap_code_space) {
	// Fail hard and early if we enter this code object again.
	byte* pointer = code->FindCodeAgeSequence();
	if (pointer != NULL) {
	pointer += kNoCodeAgeSequenceLength;
	} else {
	pointer = code->instruction_start();
	}
	CodePatcher patcher(pointer, 1);
	patcher.masm()->bkpt(0);

	DeoptimizationInputData* data =
	DeoptimizationInputData::cast(code->deoptimization_data());
	int osr_offset = data->OsrPcOffset()->value();
	if (osr_offset > 0) {
	CodePatcher osr_patcher(code->instruction_start() + osr_offset, 1);
	osr_patcher.masm()->bkpt(0);
	}
	}

	DeoptimizationInputData* deopt_data =
	DeoptimizationInputData::cast(code->deoptimization_data());
	#ifdef DEBUG
	Address prev_call_address = NULL;
	#endif
	// For each LLazyBailout instruction insert a call to the corresponding
	// deoptimization entry.
	for (int i = 0; i < deopt_data->DeoptCount(); i++) {
	if (deopt_data->Pc(i)->value() == -1) continue;
	Address call_address = code_start_address + deopt_data->Pc(i)->value();
	Address deopt_entry = GetDeoptimizationEntry(isolate, i, LAZY);
	// We need calls to have a predictable size in the unoptimized code, but
	// this is optimized code, so we don't have to have a predictable size.
	int call_size_in_bytes =
	MacroAssembler::CallSizeNotPredictableCodeSize(isolate,
	deopt_entry,
	RelocInfo::NONE32);
	int call_size_in_words = call_size_in_bytes / Assembler::kInstrSize;
	DCHECK(call_size_in_bytes % Assembler::kInstrSize == 0);
	DCHECK(call_size_in_bytes <= patch_size());
	CodePatcher patcher(call_address, call_size_in_words);
	patcher.masm()->Call(deopt_entry, RelocInfo::NONE32);
	DCHECK(prev_call_address == NULL \|\|
	call_address >= prev_call_address + patch_size());
	DCHECK(call_address + patch_size() <= code->instruction_end());
	#ifdef DEBUG
	prev_call_address = call_address;
	#endif
	}
	}


	void Deoptimizer::FillInputFrame(Address tos, JavaScriptFrame* frame) {
	// Set the register values. The values are not important as there are no
	// callee saved registers in JavaScript frames, so all registers are
	// spilled. Registers fp and sp are set to the correct values though.

	for (int i = 0; i < Register::kNumRegisters; i++) {
	input_->SetRegister(i, i * 4);
	}
	input_->SetRegister(sp.code(), reinterpret_cast<intptr_t>(frame->sp()));
	input_->SetRegister(fp.code(), reinterpret_cast<intptr_t>(frame->fp()));
	for (int i = 0; i < DoubleRegister::NumAllocatableRegisters(); i++) {
	input_->SetDoubleRegister(i, 0.0);
	}

	// Fill the frame content from the actual data on the frame.
	for (unsigned i = 0; i < input_->GetFrameSize(); i += kPointerSize) {
	input_->SetFrameSlot(i, Memory::uint32_at(tos + i));
	}
	}


	void Deoptimizer::SetPlatformCompiledStubRegisters(
	FrameDescription* output_frame, CodeStubDescriptor* descriptor) {
	ApiFunction function(descriptor->deoptimization_handler());
	ExternalReference xref(&function, ExternalReference::BUILTIN_CALL, isolate_);
	intptr_t handler = reinterpret_cast<intptr_t>(xref.address());
	int params = descriptor->GetHandlerParameterCount();
	output_frame->SetRegister(r0.code(), params);
	output_frame->SetRegister(r1.code(), handler);
	}


	void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
	for (int i = 0; i < DwVfpRegister::kMaxNumRegisters; ++i) {
	double double_value = input_->GetDoubleRegister(i);
	output_frame->SetDoubleRegister(i, double_value);
	}
	}


	bool Deoptimizer::HasAlignmentPadding(JSFunction* function) {
	// There is no dynamic alignment padding on ARM in the input frame.
	return false;
	}


	#define __ masm()->

	// This code tries to be close to ia32 code so that any changes can be
	// easily ported.
	void Deoptimizer::EntryGenerator::Generate() {
	GeneratePrologue();

	// Save all general purpose registers before messing with them.
	const int kNumberOfRegisters = Register::kNumRegisters;

	// Everything but pc, lr and ip which will be saved but not restored.
	RegList restored_regs = kJSCallerSaved \| kCalleeSaved \| ip.bit();

	const int kDoubleRegsSize =
	kDoubleSize * DwVfpRegister::kMaxNumAllocatableRegisters;

	// Save all allocatable VFP registers before messing with them.
	DCHECK(kDoubleRegZero.code() == 14);
	DCHECK(kScratchDoubleReg.code() == 15);

	// Check CPU flags for number of registers, setting the Z condition flag.
	__ CheckFor32DRegs(ip);

	// Push registers d0-d13, and possibly d16-d31, on the stack.
	// If d16-d31 are not pushed, decrease the stack pointer instead.
	__ vstm(db_w, sp, d16, d31, ne);
	__ sub(sp, sp, Operand(16 * kDoubleSize), LeaveCC, eq);
	__ vstm(db_w, sp, d0, d13);

	// Push all 16 registers (needed to populate FrameDescription::registers_).
	// TODO(1588) Note that using pc with stm is deprecated, so we should perhaps
	// handle this a bit differently.
	__ stm(db_w, sp, restored_regs \| sp.bit() \| lr.bit() \| pc.bit());

	const int kSavedRegistersAreaSize =
	(kNumberOfRegisters * kPointerSize) + kDoubleRegsSize;

	// Get the bailout id from the stack.
	__ ldr(r2, MemOperand(sp, kSavedRegistersAreaSize));

	// Get the address of the location in the code object (r3) (return
	// address for lazy deoptimization) and compute the fp-to-sp delta in
	// register r4.
	__ mov(r3, lr);
	// Correct one word for bailout id.
	__ add(r4, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
	__ sub(r4, fp, r4);

	// Allocate a new deoptimizer object.
	// Pass four arguments in r0 to r3 and fifth argument on stack.
	__ PrepareCallCFunction(6, r5);
	__ ldr(r0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
	__ mov(r1, Operand(type())); // bailout type,
	// r2: bailout id already loaded.
	// r3: code address or 0 already loaded.
	__ str(r4, MemOperand(sp, 0 * kPointerSize)); // Fp-to-sp delta.
	__ mov(r5, Operand(ExternalReference::isolate_address(isolate())));
	__ str(r5, MemOperand(sp, 1 * kPointerSize)); // Isolate.
	// Call Deoptimizer::New().
	{
	AllowExternalCallThatCantCauseGC scope(masm());
	__ CallCFunction(ExternalReference::new_deoptimizer_function(isolate()), 6);
	}

	// Preserve "deoptimizer" object in register r0 and get the input
	// frame descriptor pointer to r1 (deoptimizer->input_);
	__ ldr(r1, MemOperand(r0, Deoptimizer::input_offset()));

	// Copy core registers into FrameDescription::registers_[kNumRegisters].
	DCHECK(Register::kNumRegisters == kNumberOfRegisters);
	for (int i = 0; i < kNumberOfRegisters; i++) {
	int offset = (i * kPointerSize) + FrameDescription::registers_offset();
	__ ldr(r2, MemOperand(sp, i * kPointerSize));
	__ str(r2, MemOperand(r1, offset));
	}

	// Copy VFP registers to
	// double_registers_[DoubleRegister::kMaxNumAllocatableRegisters]
	int double_regs_offset = FrameDescription::double_registers_offset();
	for (int i = 0; i < DwVfpRegister::kMaxNumAllocatableRegisters; ++i) {
	int dst_offset = i * kDoubleSize + double_regs_offset;
	int src_offset = i * kDoubleSize + kNumberOfRegisters * kPointerSize;
	__ vldr(d0, sp, src_offset);
	__ vstr(d0, r1, dst_offset);
	}

	// Remove the bailout id and the saved registers from the stack.
	__ add(sp, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));

	// Compute a pointer to the unwinding limit in register r2; that is
	// the first stack slot not part of the input frame.
	__ ldr(r2, MemOperand(r1, FrameDescription::frame_size_offset()));
	__ add(r2, r2, 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.
	__ add(r3, r1, Operand(FrameDescription::frame_content_offset()));
	Label pop_loop;
	Label pop_loop_header;
	__ b(&pop_loop_header);
	__ bind(&pop_loop);
	__ pop(r4);
	__ str(r4, MemOperand(r3, 0));
	__ add(r3, r3, Operand(sizeof(uint32_t)));
	__ bind(&pop_loop_header);
	__ cmp(r2, sp);
	__ b(ne, &pop_loop);

	// Compute the output frame in the deoptimizer.
	__ push(r0); // Preserve deoptimizer object across call.
	// r0: deoptimizer object; r1: scratch.
	__ PrepareCallCFunction(1, r1);
	// Call Deoptimizer::ComputeOutputFrames().
	{
	AllowExternalCallThatCantCauseGC scope(masm());
	__ CallCFunction(
	ExternalReference::compute_output_frames_function(isolate()), 1);
	}
	__ pop(r0); // Restore deoptimizer object (class Deoptimizer).

	// 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: r4 = current "FrameDescription** output_",
	// r1 = one past the last FrameDescription**.
	__ ldr(r1, MemOperand(r0, Deoptimizer::output_count_offset()));
	__ ldr(r4, MemOperand(r0, Deoptimizer::output_offset())); // r4 is output_.
	__ add(r1, r4, Operand(r1, LSL, 2));
	__ jmp(&outer_loop_header);
	__ bind(&outer_push_loop);
	// Inner loop state: r2 = current FrameDescription*, r3 = loop index.
	__ ldr(r2, MemOperand(r4, 0)); // output_[ix]
	__ ldr(r3, MemOperand(r2, FrameDescription::frame_size_offset()));
	__ jmp(&inner_loop_header);
	__ bind(&inner_push_loop);
	__ sub(r3, r3, Operand(sizeof(uint32_t)));
	__ add(r6, r2, Operand(r3));
	__ ldr(r6, MemOperand(r6, FrameDescription::frame_content_offset()));
	__ push(r6);
	__ bind(&inner_loop_header);
	__ cmp(r3, Operand::Zero());
	__ b(ne, &inner_push_loop); // test for gt?
	__ add(r4, r4, Operand(kPointerSize));
	__ bind(&outer_loop_header);
	__ cmp(r4, r1);
	__ b(lt, &outer_push_loop);

	// Check CPU flags for number of registers, setting the Z condition flag.
	__ CheckFor32DRegs(ip);

	__ ldr(r1, MemOperand(r0, Deoptimizer::input_offset()));
	int src_offset = FrameDescription::double_registers_offset();
	for (int i = 0; i < DwVfpRegister::kMaxNumRegisters; ++i) {
	if (i == kDoubleRegZero.code()) continue;
	if (i == kScratchDoubleReg.code()) continue;

	const DwVfpRegister reg = DwVfpRegister::from_code(i);
	__ vldr(reg, r1, src_offset, i < 16 ? al : ne);
	src_offset += kDoubleSize;
	}

	// Push state, pc, and continuation from the last output frame.
	__ ldr(r6, MemOperand(r2, FrameDescription::state_offset()));
	__ push(r6);
	__ ldr(r6, MemOperand(r2, FrameDescription::pc_offset()));
	__ push(r6);
	__ ldr(r6, MemOperand(r2, FrameDescription::continuation_offset()));
	__ push(r6);

	// Push the registers from the last output frame.
	for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
	int offset = (i * kPointerSize) + FrameDescription::registers_offset();
	__ ldr(r6, MemOperand(r2, offset));
	__ push(r6);
	}

	// Restore the registers from the stack.
	__ ldm(ia_w, sp, restored_regs); // all but pc registers.
	__ pop(ip); // remove sp
	__ pop(ip); // remove lr

	__ InitializeRootRegister();

	__ pop(ip); // remove pc
	__ pop(ip); // get continuation, leave pc on stack
	__ pop(lr);
	__ Jump(ip);
	__ stop("Unreachable.");
	}


	void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
	// Create a sequence of deoptimization entries.
	// Note that registers are still live when jumping to an entry.
	Label done;
	for (int i = 0; i < count(); i++) {
	int start = masm()->pc_offset();
	USE(start);
	__ mov(ip, Operand(i));
	__ b(&done);
	DCHECK(masm()->pc_offset() - start == table_entry_size_);
	}
	__ bind(&done);
	__ push(ip);
	}


	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) {
	DCHECK(FLAG_enable_ool_constant_pool);
	SetFrameSlot(offset, value);
	}


	#undef __

	} } // namespace v8::internal