deps/v8/src/arm/deoptimizer-arm.cc
// 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, CodeStubInterfaceDescriptor* 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