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// 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/codegen/assembler-inl.h"
#include "src/codegen/macro-assembler.h"
#include "src/codegen/register-configuration.h"
#include "src/codegen/safepoint-table.h"
#include "src/deoptimizer/deoptimizer.h"
namespace v8 {
namespace internal {
const bool Deoptimizer::kSupportsFixedDeoptExitSize = false;
const int Deoptimizer::kDeoptExitSize = 0;
#define __ masm->
// This code tries to be close to ia32 code so that any changes can be
// easily ported.
void Deoptimizer::GenerateDeoptimizationEntries(MacroAssembler* masm,
Isolate* isolate,
DeoptimizeKind deopt_kind) {
NoRootArrayScope no_root_array(masm);
// Unlike on ARM we don't save all the registers, just the useful ones.
// For the rest, there are gaps on the stack, so the offsets remain the same.
const int kNumberOfRegisters = Register::kNumRegisters;
RegList restored_regs = kJSCallerSaved | kCalleeSaved;
RegList saved_regs = restored_regs | sp.bit();
const int kDoubleRegsSize = kDoubleSize * DoubleRegister::kNumRegisters;
// Save all double registers before messing with them.
__ subi(sp, sp, Operand(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;
__ stfd(dreg, MemOperand(sp, offset));
}
// Push saved_regs (needed to populate FrameDescription::registers_).
// Leave gaps for other registers.
__ subi(sp, sp, Operand(kNumberOfRegisters * kPointerSize));
for (int16_t i = kNumberOfRegisters - 1; i >= 0; i--) {
if ((saved_regs & (1 << i)) != 0) {
__ StoreP(ToRegister(i), MemOperand(sp, kPointerSize * i));
}
}
{
UseScratchRegisterScope temps(masm);
Register scratch = temps.Acquire();
__ mov(scratch, Operand(ExternalReference::Create(
IsolateAddressId::kCEntryFPAddress, isolate)));
__ StoreP(fp, MemOperand(scratch));
}
const int kSavedRegistersAreaSize =
(kNumberOfRegisters * kPointerSize) + kDoubleRegsSize;
// Get the bailout id is passed as r29 by the caller.
__ mr(r5, r29);
// Get the address of the location in the code object (r6) (return
// address for lazy deoptimization) and compute the fp-to-sp delta in
// register r7.
__ mflr(r6);
__ addi(r7, sp, Operand(kSavedRegistersAreaSize));
__ sub(r7, fp, r7);
// Allocate a new deoptimizer object.
// Pass six arguments in r3 to r8.
__ PrepareCallCFunction(6, r8);
__ li(r3, Operand::Zero());
Label context_check;
__ LoadP(r4, MemOperand(fp, CommonFrameConstants::kContextOrFrameTypeOffset));
__ JumpIfSmi(r4, &context_check);
__ LoadP(r3, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
__ bind(&context_check);
__ li(r4, Operand(static_cast<int>(deopt_kind)));
// r5: bailout id already loaded.
// r6: code address or 0 already loaded.
// r7: Fp-to-sp delta.
__ mov(r8, Operand(ExternalReference::isolate_address(isolate)));
// Call Deoptimizer::New().
{
AllowExternalCallThatCantCauseGC scope(masm);
__ CallCFunction(ExternalReference::new_deoptimizer_function(), 6);
}
// Preserve "deoptimizer" object in register r3 and get the input
// frame descriptor pointer to r4 (deoptimizer->input_);
__ LoadP(r4, MemOperand(r3, Deoptimizer::input_offset()));
// Copy core registers into FrameDescription::registers_[kNumRegisters].
DCHECK_EQ(Register::kNumRegisters, kNumberOfRegisters);
for (int i = 0; i < kNumberOfRegisters; i++) {
int offset = (i * kPointerSize) + FrameDescription::registers_offset();
__ LoadP(r5, MemOperand(sp, i * kPointerSize));
__ StoreP(r5, MemOperand(r4, 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;
__ lfd(d0, MemOperand(sp, src_offset));
__ stfd(d0, MemOperand(r4, dst_offset));
}
// Remove the saved registers from the stack.
__ addi(sp, sp, Operand(kSavedRegistersAreaSize));
// Compute a pointer to the unwinding limit in register r5; that is
// the first stack slot not part of the input frame.
__ LoadP(r5, MemOperand(r4, FrameDescription::frame_size_offset()));
__ add(r5, r5, 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.
__ addi(r6, r4, Operand(FrameDescription::frame_content_offset()));
Label pop_loop;
Label pop_loop_header;
__ b(&pop_loop_header);
__ bind(&pop_loop);
__ pop(r7);
__ StoreP(r7, MemOperand(r6, 0));
__ addi(r6, r6, Operand(kPointerSize));
__ bind(&pop_loop_header);
__ cmp(r5, sp);
__ bne(&pop_loop);
// Compute the output frame in the deoptimizer.
__ push(r3); // Preserve deoptimizer object across call.
// r3: deoptimizer object; r4: scratch.
__ PrepareCallCFunction(1, r4);
// Call Deoptimizer::ComputeOutputFrames().
{
AllowExternalCallThatCantCauseGC scope(masm);
__ CallCFunction(ExternalReference::compute_output_frames_function(), 1);
}
__ pop(r3); // Restore deoptimizer object (class Deoptimizer).
__ LoadP(sp, MemOperand(r3, 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: r7 = current "FrameDescription** output_",
// r4 = one past the last FrameDescription**.
__ lwz(r4, MemOperand(r3, Deoptimizer::output_count_offset()));
__ LoadP(r7, MemOperand(r3, Deoptimizer::output_offset())); // r7 is output_.
__ ShiftLeftImm(r4, r4, Operand(kPointerSizeLog2));
__ add(r4, r7, r4);
__ b(&outer_loop_header);
__ bind(&outer_push_loop);
// Inner loop state: r5 = current FrameDescription*, r6 = loop index.
__ LoadP(r5, MemOperand(r7, 0)); // output_[ix]
__ LoadP(r6, MemOperand(r5, FrameDescription::frame_size_offset()));
__ b(&inner_loop_header);
__ bind(&inner_push_loop);
__ addi(r6, r6, Operand(-sizeof(intptr_t)));
__ add(r9, r5, r6);
__ LoadP(r9, MemOperand(r9, FrameDescription::frame_content_offset()));
__ push(r9);
__ bind(&inner_loop_header);
__ cmpi(r6, Operand::Zero());
__ bne(&inner_push_loop); // test for gt?
__ addi(r7, r7, Operand(kPointerSize));
__ bind(&outer_loop_header);
__ cmp(r7, r4);
__ blt(&outer_push_loop);
__ LoadP(r4, MemOperand(r3, 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;
__ lfd(dreg, MemOperand(r4, src_offset));
}
// Push pc, and continuation from the last output frame.
__ LoadP(r9, MemOperand(r5, FrameDescription::pc_offset()));
__ push(r9);
__ LoadP(r9, MemOperand(r5, FrameDescription::continuation_offset()));
__ push(r9);
// Restore the registers from the last output frame.
{
UseScratchRegisterScope temps(masm);
Register scratch = temps.Acquire();
DCHECK(!(scratch.bit() & restored_regs));
__ mr(scratch, r5);
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(scratch, offset));
}
}
}
{
UseScratchRegisterScope temps(masm);
Register scratch = temps.Acquire();
__ pop(scratch); // get continuation, leave pc on stack
__ pop(r0);
__ mtlr(r0);
__ Jump(scratch);
}
__ stop();
}
Float32 RegisterValues::GetFloatRegister(unsigned n) const {
float float_val = static_cast<float>(double_registers_[n].get_scalar());
return Float32::FromBits(bit_cast<uint32_t>(float_val));
}
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_embedded_constant_pool);
SetFrameSlot(offset, value);
}
#undef __
} // namespace internal
} // namespace v8
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