// Copyright 2014 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "src/assembler-inl.h"
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#include "src/deoptimizer.h"
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#include "src/register-configuration.h"
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#include "src/safepoint-table.h"
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namespace v8 {
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namespace internal {
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const int Deoptimizer::table_entry_size_ = 8;
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#define __ masm()->
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// This code tries to be close to ia32 code so that any changes can be
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// easily ported.
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void Deoptimizer::TableEntryGenerator::Generate() {
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GeneratePrologue();
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// Unlike on ARM we don't save all the registers, just the useful ones.
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// For the rest, there are gaps on the stack, so the offsets remain the same.
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const int kNumberOfRegisters = Register::kNumRegisters;
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RegList restored_regs = kJSCallerSaved | kCalleeSaved;
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RegList saved_regs = restored_regs | sp.bit();
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const int kDoubleRegsSize = kDoubleSize * DoubleRegister::kNumRegisters;
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const int kFloatRegsSize = kFloatSize * FloatRegister::kNumRegisters;
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// Save all double registers before messing with them.
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__ subi(sp, sp, Operand(kDoubleRegsSize));
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const RegisterConfiguration* config = RegisterConfiguration::Default();
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for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
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int code = config->GetAllocatableDoubleCode(i);
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const DoubleRegister dreg = DoubleRegister::from_code(code);
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int offset = code * kDoubleSize;
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__ stfd(dreg, MemOperand(sp, offset));
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}
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// Save all float registers before messing with them.
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__ subi(sp, sp, Operand(kFloatRegsSize));
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for (int i = 0; i < config->num_allocatable_float_registers(); ++i) {
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int code = config->GetAllocatableFloatCode(i);
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const FloatRegister freg = FloatRegister::from_code(code);
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int offset = code * kFloatSize;
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__ stfs(freg, MemOperand(sp, offset));
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}
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// Push saved_regs (needed to populate FrameDescription::registers_).
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// Leave gaps for other registers.
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__ subi(sp, sp, Operand(kNumberOfRegisters * kPointerSize));
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for (int16_t i = kNumberOfRegisters - 1; i >= 0; i--) {
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if ((saved_regs & (1 << i)) != 0) {
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__ StoreP(ToRegister(i), MemOperand(sp, kPointerSize * i));
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}
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}
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__ mov(ip, Operand(ExternalReference::Create(
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IsolateAddressId::kCEntryFPAddress, isolate())));
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__ StoreP(fp, MemOperand(ip));
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const int kSavedRegistersAreaSize =
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(kNumberOfRegisters * kPointerSize) + kDoubleRegsSize + kFloatRegsSize;
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// Get the bailout id from the stack.
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__ LoadP(r5, MemOperand(sp, kSavedRegistersAreaSize));
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// Get the address of the location in the code object (r6) (return
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// address for lazy deoptimization) and compute the fp-to-sp delta in
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// register r7.
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__ mflr(r6);
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// Correct one word for bailout id.
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__ addi(r7, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
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__ sub(r7, fp, r7);
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// Allocate a new deoptimizer object.
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// Pass six arguments in r3 to r8.
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__ PrepareCallCFunction(6, r8);
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__ li(r3, Operand::Zero());
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Label context_check;
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__ LoadP(r4, MemOperand(fp, CommonFrameConstants::kContextOrFrameTypeOffset));
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__ JumpIfSmi(r4, &context_check);
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__ LoadP(r3, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
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__ bind(&context_check);
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__ li(r4, Operand(static_cast<int>(deopt_kind())));
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// r5: bailout id already loaded.
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// r6: code address or 0 already loaded.
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// r7: Fp-to-sp delta.
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__ mov(r8, Operand(ExternalReference::isolate_address(isolate())));
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// Call Deoptimizer::New().
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{
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AllowExternalCallThatCantCauseGC scope(masm());
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__ CallCFunction(ExternalReference::new_deoptimizer_function(), 6);
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}
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// Preserve "deoptimizer" object in register r3 and get the input
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// frame descriptor pointer to r4 (deoptimizer->input_);
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__ LoadP(r4, MemOperand(r3, Deoptimizer::input_offset()));
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// Copy core registers into FrameDescription::registers_[kNumRegisters].
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DCHECK_EQ(Register::kNumRegisters, kNumberOfRegisters);
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for (int i = 0; i < kNumberOfRegisters; i++) {
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int offset = (i * kPointerSize) + FrameDescription::registers_offset();
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__ LoadP(r5, MemOperand(sp, i * kPointerSize));
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__ StoreP(r5, MemOperand(r4, offset));
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}
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int double_regs_offset = FrameDescription::double_registers_offset();
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// Copy double registers to
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// double_registers_[DoubleRegister::kNumRegisters]
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for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
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int code = config->GetAllocatableDoubleCode(i);
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int dst_offset = code * kDoubleSize + double_regs_offset;
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int src_offset =
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code * kDoubleSize + kNumberOfRegisters * kPointerSize + kFloatRegsSize;
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__ lfd(d0, MemOperand(sp, src_offset));
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__ stfd(d0, MemOperand(r4, dst_offset));
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}
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int float_regs_offset = FrameDescription::float_registers_offset();
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// Copy float registers to
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// float_registers_[FloatRegister::kNumRegisters]
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for (int i = 0; i < config->num_allocatable_float_registers(); ++i) {
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int code = config->GetAllocatableFloatCode(i);
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int dst_offset = code * kFloatSize + float_regs_offset;
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int src_offset = code * kFloatSize + kNumberOfRegisters * kPointerSize;
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__ lfs(d0, MemOperand(sp, src_offset));
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__ stfs(d0, MemOperand(r4, dst_offset));
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}
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// Remove the bailout id and the saved registers from the stack.
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__ addi(sp, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
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// Compute a pointer to the unwinding limit in register r5; that is
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// the first stack slot not part of the input frame.
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__ LoadP(r5, MemOperand(r4, FrameDescription::frame_size_offset()));
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__ add(r5, r5, sp);
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// Unwind the stack down to - but not including - the unwinding
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// limit and copy the contents of the activation frame to the input
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// frame description.
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__ addi(r6, r4, Operand(FrameDescription::frame_content_offset()));
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Label pop_loop;
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Label pop_loop_header;
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__ b(&pop_loop_header);
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__ bind(&pop_loop);
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__ pop(r7);
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__ StoreP(r7, MemOperand(r6, 0));
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__ addi(r6, r6, Operand(kPointerSize));
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__ bind(&pop_loop_header);
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__ cmp(r5, sp);
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__ bne(&pop_loop);
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// Compute the output frame in the deoptimizer.
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__ push(r3); // Preserve deoptimizer object across call.
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// r3: deoptimizer object; r4: scratch.
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__ PrepareCallCFunction(1, r4);
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// Call Deoptimizer::ComputeOutputFrames().
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{
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AllowExternalCallThatCantCauseGC scope(masm());
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__ CallCFunction(ExternalReference::compute_output_frames_function(), 1);
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}
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__ pop(r3); // Restore deoptimizer object (class Deoptimizer).
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__ LoadP(sp, MemOperand(r3, Deoptimizer::caller_frame_top_offset()));
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// Replace the current (input) frame with the output frames.
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Label outer_push_loop, inner_push_loop, outer_loop_header, inner_loop_header;
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// Outer loop state: r7 = current "FrameDescription** output_",
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// r4 = one past the last FrameDescription**.
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__ lwz(r4, MemOperand(r3, Deoptimizer::output_count_offset()));
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__ LoadP(r7, MemOperand(r3, Deoptimizer::output_offset())); // r7 is output_.
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__ ShiftLeftImm(r4, r4, Operand(kPointerSizeLog2));
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__ add(r4, r7, r4);
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__ b(&outer_loop_header);
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__ bind(&outer_push_loop);
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// Inner loop state: r5 = current FrameDescription*, r6 = loop index.
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__ LoadP(r5, MemOperand(r7, 0)); // output_[ix]
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__ LoadP(r6, MemOperand(r5, FrameDescription::frame_size_offset()));
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__ b(&inner_loop_header);
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__ bind(&inner_push_loop);
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__ addi(r6, r6, Operand(-sizeof(intptr_t)));
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__ add(r9, r5, r6);
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__ LoadP(r9, MemOperand(r9, FrameDescription::frame_content_offset()));
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__ push(r9);
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__ bind(&inner_loop_header);
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__ cmpi(r6, Operand::Zero());
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__ bne(&inner_push_loop); // test for gt?
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__ addi(r7, r7, Operand(kPointerSize));
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__ bind(&outer_loop_header);
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__ cmp(r7, r4);
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__ blt(&outer_push_loop);
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__ LoadP(r4, MemOperand(r3, Deoptimizer::input_offset()));
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for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
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int code = config->GetAllocatableDoubleCode(i);
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const DoubleRegister dreg = DoubleRegister::from_code(code);
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int src_offset = code * kDoubleSize + double_regs_offset;
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__ lfd(dreg, MemOperand(r4, src_offset));
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}
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// Push pc, and continuation from the last output frame.
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__ LoadP(r9, MemOperand(r5, FrameDescription::pc_offset()));
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__ push(r9);
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__ LoadP(r9, MemOperand(r5, FrameDescription::continuation_offset()));
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__ push(r9);
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// Restore the registers from the last output frame.
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DCHECK(!(ip.bit() & restored_regs));
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__ mr(ip, r5);
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for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
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int offset = (i * kPointerSize) + FrameDescription::registers_offset();
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if ((restored_regs & (1 << i)) != 0) {
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__ LoadP(ToRegister(i), MemOperand(ip, offset));
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}
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}
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__ InitializeRootRegister();
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__ pop(ip); // get continuation, leave pc on stack
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__ pop(r0);
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__ mtlr(r0);
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__ Jump(ip);
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__ stop("Unreachable.");
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}
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void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
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Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm());
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// Create a sequence of deoptimization entries.
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// Note that registers are still live when jumping to an entry.
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Label done;
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for (int i = 0; i < count(); i++) {
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int start = masm()->pc_offset();
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USE(start);
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__ li(ip, Operand(i));
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__ b(&done);
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DCHECK(masm()->pc_offset() - start == table_entry_size_);
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}
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__ bind(&done);
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__ push(ip);
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}
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bool Deoptimizer::PadTopOfStackRegister() { return false; }
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void FrameDescription::SetCallerPc(unsigned offset, intptr_t value) {
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SetFrameSlot(offset, value);
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}
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void FrameDescription::SetCallerFp(unsigned offset, intptr_t value) {
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SetFrameSlot(offset, value);
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}
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void FrameDescription::SetCallerConstantPool(unsigned offset, intptr_t value) {
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DCHECK(FLAG_enable_embedded_constant_pool);
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SetFrameSlot(offset, value);
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}
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#undef __
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} // namespace internal
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} // namespace v8
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