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// Copyright 2013 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/api.h"
#include "src/arm64/assembler-arm64-inl.h"
#include "src/arm64/macro-assembler-arm64-inl.h"
#include "src/deoptimizer.h"
#include "src/frame-constants.h"
#include "src/register-configuration.h"
#include "src/safepoint-table.h"
namespace v8 {
namespace internal {
#define __ masm->
namespace {
void CopyRegListToFrame(MacroAssembler* masm, const Register& dst,
int dst_offset, const CPURegList& reg_list,
const Register& temp0, const Register& temp1,
int src_offset = 0) {
DCHECK_EQ(reg_list.Count() % 2, 0);
UseScratchRegisterScope temps(masm);
CPURegList copy_to_input = reg_list;
int reg_size = reg_list.RegisterSizeInBytes();
DCHECK_EQ(temp0.SizeInBytes(), reg_size);
DCHECK_EQ(temp1.SizeInBytes(), reg_size);
// Compute some temporary addresses to avoid having the macro assembler set
// up a temp with an offset for accesses out of the range of the addressing
// mode.
Register src = temps.AcquireX();
masm->Add(src, sp, src_offset);
masm->Add(dst, dst, dst_offset);
// Write reg_list into the frame pointed to by dst.
for (int i = 0; i < reg_list.Count(); i += 2) {
masm->Ldp(temp0, temp1, MemOperand(src, i * reg_size));
CPURegister reg0 = copy_to_input.PopLowestIndex();
CPURegister reg1 = copy_to_input.PopLowestIndex();
int offset0 = reg0.code() * reg_size;
int offset1 = reg1.code() * reg_size;
// Pair up adjacent stores, otherwise write them separately.
if (offset1 == offset0 + reg_size) {
masm->Stp(temp0, temp1, MemOperand(dst, offset0));
} else {
masm->Str(temp0, MemOperand(dst, offset0));
masm->Str(temp1, MemOperand(dst, offset1));
}
}
masm->Sub(dst, dst, dst_offset);
}
void RestoreRegList(MacroAssembler* masm, const CPURegList& reg_list,
const Register& src_base, int src_offset) {
DCHECK_EQ(reg_list.Count() % 2, 0);
UseScratchRegisterScope temps(masm);
CPURegList restore_list = reg_list;
int reg_size = restore_list.RegisterSizeInBytes();
// Compute a temporary addresses to avoid having the macro assembler set
// up a temp with an offset for accesses out of the range of the addressing
// mode.
Register src = temps.AcquireX();
masm->Add(src, src_base, src_offset);
#if defined(V8_OS_WIN)
// x18 is reserved as platform register on Windows.
restore_list.Remove(x18);
#endif
// Restore every register in restore_list from src.
while (!restore_list.IsEmpty()) {
CPURegister reg0 = restore_list.PopLowestIndex();
CPURegister reg1 = restore_list.PopLowestIndex();
int offset0 = reg0.code() * reg_size;
#if defined(V8_OS_WIN)
if (reg1 == NoCPUReg) {
masm->Ldr(reg0, MemOperand(src, offset0));
break;
}
#endif
int offset1 = reg1.code() * reg_size;
// Pair up adjacent loads, otherwise read them separately.
if (offset1 == offset0 + reg_size) {
masm->Ldp(reg0, reg1, MemOperand(src, offset0));
} else {
masm->Ldr(reg0, MemOperand(src, offset0));
masm->Ldr(reg1, MemOperand(src, offset1));
}
}
}
} // namespace
void Deoptimizer::GenerateDeoptimizationEntries(MacroAssembler* masm,
Isolate* isolate,
DeoptimizeKind deopt_kind) {
NoRootArrayScope no_root_array(masm);
// TODO(all): This code needs to be revisited. We probably only need to save
// caller-saved registers here. Callee-saved registers can be stored directly
// in the input frame.
// Save all allocatable double registers.
CPURegList saved_double_registers(
CPURegister::kVRegister, kDRegSizeInBits,
RegisterConfiguration::Default()->allocatable_double_codes_mask());
DCHECK_EQ(saved_double_registers.Count() % 2, 0);
__ PushCPURegList(saved_double_registers);
CPURegList saved_float_registers(
CPURegister::kVRegister, kSRegSizeInBits,
RegisterConfiguration::Default()->allocatable_float_codes_mask());
DCHECK_EQ(saved_float_registers.Count() % 4, 0);
__ PushCPURegList(saved_float_registers);
// We save all the registers except sp, lr and the masm scratches.
CPURegList saved_registers(CPURegister::kRegister, kXRegSizeInBits, 0, 28);
saved_registers.Remove(ip0);
saved_registers.Remove(ip1);
saved_registers.Combine(fp);
DCHECK_EQ(saved_registers.Count() % 2, 0);
__ PushCPURegList(saved_registers);
__ Mov(x3, Operand(ExternalReference::Create(
IsolateAddressId::kCEntryFPAddress, isolate)));
__ Str(fp, MemOperand(x3));
const int kSavedRegistersAreaSize =
(saved_registers.Count() * kXRegSize) +
(saved_double_registers.Count() * kDRegSize) +
(saved_float_registers.Count() * kSRegSize);
// Floating point registers are saved on the stack above core registers.
const int kFloatRegistersOffset = saved_registers.Count() * kXRegSize;
const int kDoubleRegistersOffset =
kFloatRegistersOffset + saved_float_registers.Count() * kSRegSize;
// The bailout id was passed by the caller in x26.
Register bailout_id = x2;
__ Mov(bailout_id, x26);
Register code_object = x3;
Register fp_to_sp = x4;
// Get the address of the location in the code object. This is the return
// address for lazy deoptimization.
__ Mov(code_object, lr);
// Compute the fp-to-sp delta.
__ Add(fp_to_sp, sp, kSavedRegistersAreaSize);
__ Sub(fp_to_sp, fp, fp_to_sp);
// Allocate a new deoptimizer object.
__ Ldr(x1, MemOperand(fp, CommonFrameConstants::kContextOrFrameTypeOffset));
// Ensure we can safely load from below fp.
DCHECK_GT(kSavedRegistersAreaSize,
-JavaScriptFrameConstants::kFunctionOffset);
__ Ldr(x0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
// If x1 is a smi, zero x0.
__ Tst(x1, kSmiTagMask);
__ CzeroX(x0, eq);
__ Mov(x1, static_cast<int>(deopt_kind));
// Following arguments are already loaded:
// - x2: bailout id
// - x3: code object address
// - x4: fp-to-sp delta
__ Mov(x5, ExternalReference::isolate_address(isolate));
{
// Call Deoptimizer::New().
AllowExternalCallThatCantCauseGC scope(masm);
__ CallCFunction(ExternalReference::new_deoptimizer_function(), 6);
}
// Preserve "deoptimizer" object in register x0.
Register deoptimizer = x0;
// Get the input frame descriptor pointer.
__ Ldr(x1, MemOperand(deoptimizer, Deoptimizer::input_offset()));
// Copy core registers into the input frame.
CopyRegListToFrame(masm, x1, FrameDescription::registers_offset(),
saved_registers, x2, x3);
// Copy double registers to the input frame.
CopyRegListToFrame(masm, x1, FrameDescription::double_registers_offset(),
saved_double_registers, x2, x3, kDoubleRegistersOffset);
// Copy float registers to the input frame.
// TODO(arm): these are the lower 32-bits of the double registers stored
// above, so we shouldn't need to store them again.
CopyRegListToFrame(masm, x1, FrameDescription::float_registers_offset(),
saved_float_registers, w2, w3, kFloatRegistersOffset);
// Remove the saved registers from the stack.
DCHECK_EQ(kSavedRegistersAreaSize % kXRegSize, 0);
__ Drop(kSavedRegistersAreaSize / kXRegSize);
// Compute a pointer to the unwinding limit in register x2; that is
// the first stack slot not part of the input frame.
Register unwind_limit = x2;
__ Ldr(unwind_limit, MemOperand(x1, FrameDescription::frame_size_offset()));
// 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(x3, x1, FrameDescription::frame_content_offset());
__ SlotAddress(x1, 0);
__ Lsr(unwind_limit, unwind_limit, kPointerSizeLog2);
__ Mov(x5, unwind_limit);
__ CopyDoubleWords(x3, x1, x5);
__ Drop(unwind_limit);
// Compute the output frame in the deoptimizer.
__ Push(padreg, x0); // Preserve deoptimizer object across call.
{
// Call Deoptimizer::ComputeOutputFrames().
AllowExternalCallThatCantCauseGC scope(masm);
__ CallCFunction(ExternalReference::compute_output_frames_function(), 1);
}
__ Pop(x4, padreg); // Restore deoptimizer object (class Deoptimizer).
{
UseScratchRegisterScope temps(masm);
Register scratch = temps.AcquireX();
__ Ldr(scratch, MemOperand(x4, Deoptimizer::caller_frame_top_offset()));
__ Mov(sp, scratch);
}
// Replace the current (input) frame with the output frames.
Label outer_push_loop, inner_push_loop,
outer_loop_header, inner_loop_header;
__ Ldrsw(x1, MemOperand(x4, Deoptimizer::output_count_offset()));
__ Ldr(x0, MemOperand(x4, Deoptimizer::output_offset()));
__ Add(x1, x0, Operand(x1, LSL, kPointerSizeLog2));
__ B(&outer_loop_header);
__ Bind(&outer_push_loop);
Register current_frame = x2;
Register frame_size = x3;
__ Ldr(current_frame, MemOperand(x0, kPointerSize, PostIndex));
__ Ldr(x3, MemOperand(current_frame, FrameDescription::frame_size_offset()));
__ Lsr(frame_size, x3, kPointerSizeLog2);
__ Claim(frame_size);
__ Add(x7, current_frame, FrameDescription::frame_content_offset());
__ SlotAddress(x6, 0);
__ CopyDoubleWords(x6, x7, frame_size);
__ Bind(&outer_loop_header);
__ Cmp(x0, x1);
__ B(lt, &outer_push_loop);
__ Ldr(x1, MemOperand(x4, Deoptimizer::input_offset()));
RestoreRegList(masm, saved_double_registers, x1,
FrameDescription::double_registers_offset());
// TODO(all): ARM copies a lot (if not all) of the last output frame onto the
// stack, then pops it all into registers. Here, we try to load it directly
// into the relevant registers. Is this correct? If so, we should improve the
// ARM code.
// Restore registers from the last output frame.
// Note that lr is not in the list of saved_registers and will be restored
// later. We can use it to hold the address of last output frame while
// reloading the other registers.
DCHECK(!saved_registers.IncludesAliasOf(lr));
Register last_output_frame = lr;
__ Mov(last_output_frame, current_frame);
RestoreRegList(masm, saved_registers, last_output_frame,
FrameDescription::registers_offset());
Register continuation = x7;
__ Ldr(continuation, MemOperand(last_output_frame,
FrameDescription::continuation_offset()));
__ Ldr(lr, MemOperand(last_output_frame, FrameDescription::pc_offset()));
__ Br(continuation);
}
bool Deoptimizer::PadTopOfStackRegister() { return true; }
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 embedded constant pool support.
UNREACHABLE();
}
#undef __
} // namespace internal
} // namespace v8