deps/v8/src/ia32/deoptimizer-ia32.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"
#if V8_TARGET_ARCH_IA32
#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_ = 10;
int Deoptimizer::patch_size() {
return Assembler::kCallInstructionLength;
}
void Deoptimizer::EnsureRelocSpaceForLazyDeoptimization(Handle<Code> code) {
Isolate* isolate = code->GetIsolate();
HandleScope scope(isolate);
// Compute the size of relocation information needed for the code
// patching in Deoptimizer::DeoptimizeFunction.
int min_reloc_size = 0;
int prev_pc_offset = 0;
DeoptimizationInputData* deopt_data =
DeoptimizationInputData::cast(code->deoptimization_data());
for (int i = 0; i < deopt_data->DeoptCount(); i++) {
int pc_offset = deopt_data->Pc(i)->value();
if (pc_offset == -1) continue;
DCHECK_GE(pc_offset, prev_pc_offset);
int pc_delta = pc_offset - prev_pc_offset;
// We use RUNTIME_ENTRY reloc info which has a size of 2 bytes
// if encodable with small pc delta encoding and up to 6 bytes
// otherwise.
if (pc_delta <= RelocInfo::kMaxSmallPCDelta) {
min_reloc_size += 2;
} else {
min_reloc_size += 6;
}
prev_pc_offset = pc_offset;
}
// If the relocation information is not big enough we create a new
// relocation info object that is padded with comments to make it
// big enough for lazy doptimization.
int reloc_length = code->relocation_info()->length();
if (min_reloc_size > reloc_length) {
int comment_reloc_size = RelocInfo::kMinRelocCommentSize;
// Padding needed.
int min_padding = min_reloc_size - reloc_length;
// Number of comments needed to take up at least that much space.
int additional_comments =
(min_padding + comment_reloc_size - 1) / comment_reloc_size;
// Actual padding size.
int padding = additional_comments * comment_reloc_size;
// Allocate new relocation info and copy old relocation to the end
// of the new relocation info array because relocation info is
// written and read backwards.
Factory* factory = isolate->factory();
Handle<ByteArray> new_reloc =
factory->NewByteArray(reloc_length + padding, TENURED);
MemCopy(new_reloc->GetDataStartAddress() + padding,
code->relocation_info()->GetDataStartAddress(), reloc_length);
// Create a relocation writer to write the comments in the padding
// space. Use position 0 for everything to ensure short encoding.
RelocInfoWriter reloc_info_writer(
new_reloc->GetDataStartAddress() + padding, 0);
intptr_t comment_string
= reinterpret_cast<intptr_t>(RelocInfo::kFillerCommentString);
RelocInfo rinfo(0, RelocInfo::COMMENT, comment_string, NULL);
for (int i = 0; i < additional_comments; ++i) {
#ifdef DEBUG
byte* pos_before = reloc_info_writer.pos();
#endif
reloc_info_writer.Write(&rinfo);
DCHECK(RelocInfo::kMinRelocCommentSize ==
pos_before - reloc_info_writer.pos());
}
// Replace relocation information on the code object.
code->set_relocation_info(*new_reloc);
}
}
void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) {
Address code_start_address = code->instruction_start();
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()->int3();
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()->int3();
}
}
// We will overwrite the code's relocation info in-place. Relocation info
// is written backward. The relocation info is the payload of a byte
// array. Later on we will slide this to the start of the byte array and
// create a filler object in the remaining space.
ByteArray* reloc_info = code->relocation_info();
Address reloc_end_address = reloc_info->address() + reloc_info->Size();
RelocInfoWriter reloc_info_writer(reloc_end_address, code_start_address);
// Since the call is a relative encoding, write new
// reloc info. We do not need any of the existing reloc info because the
// existing code will not be used again (we zap it in debug builds).
//
// Emit call to lazy deoptimization at all lazy deopt points.
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;
// Patch lazy deoptimization entry.
Address call_address = code_start_address + deopt_data->Pc(i)->value();
CodePatcher patcher(call_address, patch_size());
Address deopt_entry = GetDeoptimizationEntry(isolate, i, LAZY);
patcher.masm()->call(deopt_entry, RelocInfo::NONE32);
// We use RUNTIME_ENTRY for deoptimization bailouts.
RelocInfo rinfo(call_address + 1, // 1 after the call opcode.
RelocInfo::RUNTIME_ENTRY,
reinterpret_cast<intptr_t>(deopt_entry),
NULL);
reloc_info_writer.Write(&rinfo);
DCHECK_GE(reloc_info_writer.pos(),
reloc_info->address() + ByteArray::kHeaderSize);
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
}
// Move the relocation info to the beginning of the byte array.
int new_reloc_size = reloc_end_address - reloc_info_writer.pos();
MemMove(code->relocation_start(), reloc_info_writer.pos(), new_reloc_size);
// The relocation info is in place, update the size.
reloc_info->set_length(new_reloc_size);
// Handle the junk part after the new relocation info. We will create
// a non-live object in the extra space at the end of the former reloc info.
Address junk_address = reloc_info->address() + reloc_info->Size();
DCHECK(junk_address <= reloc_end_address);
isolate->heap()->CreateFillerObjectAt(junk_address,
reloc_end_address - junk_address);
}
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 ebp and esp are set to the correct values though.
for (int i = 0; i < Register::kNumRegisters; i++) {
input_->SetRegister(i, i * 4);
}
input_->SetRegister(esp.code(), reinterpret_cast<intptr_t>(frame->sp()));
input_->SetRegister(ebp.code(), reinterpret_cast<intptr_t>(frame->fp()));
for (int i = 0; i < XMMRegister::kMaxNumAllocatableRegisters; 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) {
intptr_t handler =
reinterpret_cast<intptr_t>(descriptor->deoptimization_handler());
int params = descriptor->GetHandlerParameterCount();
output_frame->SetRegister(eax.code(), params);
output_frame->SetRegister(ebx.code(), handler);
}
void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
for (int i = 0; i < XMMRegister::kMaxNumAllocatableRegisters; ++i) {
double double_value = input_->GetDoubleRegister(i);
output_frame->SetDoubleRegister(i, double_value);
}
}
bool Deoptimizer::HasAlignmentPadding(JSFunction* function) {
int parameter_count = function->shared()->formal_parameter_count() + 1;
unsigned input_frame_size = input_->GetFrameSize();
unsigned alignment_state_offset =
input_frame_size - parameter_count * kPointerSize -
StandardFrameConstants::kFixedFrameSize -
kPointerSize;
DCHECK(JavaScriptFrameConstants::kDynamicAlignmentStateOffset ==
JavaScriptFrameConstants::kLocal0Offset);
int32_t alignment_state = input_->GetFrameSlot(alignment_state_offset);
return (alignment_state == kAlignmentPaddingPushed);
}
#define __ masm()->
void Deoptimizer::EntryGenerator::Generate() {
GeneratePrologue();
// Save all general purpose registers before messing with them.
const int kNumberOfRegisters = Register::kNumRegisters;
const int kDoubleRegsSize = kDoubleSize *
XMMRegister::kMaxNumAllocatableRegisters;
__ sub(esp, Immediate(kDoubleRegsSize));
for (int i = 0; i < XMMRegister::kMaxNumAllocatableRegisters; ++i) {
XMMRegister xmm_reg = XMMRegister::FromAllocationIndex(i);
int offset = i * kDoubleSize;
__ movsd(Operand(esp, offset), xmm_reg);
}
__ pushad();
const int kSavedRegistersAreaSize = kNumberOfRegisters * kPointerSize +
kDoubleRegsSize;
// Get the bailout id from the stack.
__ mov(ebx, Operand(esp, kSavedRegistersAreaSize));
// Get the address of the location in the code object
// and compute the fp-to-sp delta in register edx.
__ mov(ecx, Operand(esp, kSavedRegistersAreaSize + 1 * kPointerSize));
__ lea(edx, Operand(esp, kSavedRegistersAreaSize + 2 * kPointerSize));
__ sub(edx, ebp);
__ neg(edx);
// Allocate a new deoptimizer object.
__ PrepareCallCFunction(6, eax);
__ mov(eax, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
__ mov(Operand(esp, 0 * kPointerSize), eax); // Function.
__ mov(Operand(esp, 1 * kPointerSize), Immediate(type())); // Bailout type.
__ mov(Operand(esp, 2 * kPointerSize), ebx); // Bailout id.
__ mov(Operand(esp, 3 * kPointerSize), ecx); // Code address or 0.
__ mov(Operand(esp, 4 * kPointerSize), edx); // Fp-to-sp delta.
__ mov(Operand(esp, 5 * kPointerSize),
Immediate(ExternalReference::isolate_address(isolate())));
{
AllowExternalCallThatCantCauseGC scope(masm());
__ CallCFunction(ExternalReference::new_deoptimizer_function(isolate()), 6);
}
// Preserve deoptimizer object in register eax and get the input
// frame descriptor pointer.
__ mov(ebx, Operand(eax, Deoptimizer::input_offset()));
// Fill in the input registers.
for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
int offset = (i * kPointerSize) + FrameDescription::registers_offset();
__ pop(Operand(ebx, offset));
}
int double_regs_offset = FrameDescription::double_registers_offset();
// Fill in the double input registers.
for (int i = 0; i < XMMRegister::kMaxNumAllocatableRegisters; ++i) {
int dst_offset = i * kDoubleSize + double_regs_offset;
int src_offset = i * kDoubleSize;
__ movsd(xmm0, Operand(esp, src_offset));
__ movsd(Operand(ebx, dst_offset), xmm0);
}
// Clear FPU all exceptions.
// TODO(ulan): Find out why the TOP register is not zero here in some cases,
// and check that the generated code never deoptimizes with unbalanced stack.
__ fnclex();
// Remove the bailout id, return address and the double registers.
__ add(esp, Immediate(kDoubleRegsSize + 2 * kPointerSize));
// Compute a pointer to the unwinding limit in register ecx; that is
// the first stack slot not part of the input frame.
__ mov(ecx, Operand(ebx, FrameDescription::frame_size_offset()));
__ add(ecx, esp);
// Unwind the stack down to - but not including - the unwinding
// limit and copy the contents of the activation frame to the input
// frame description.
__ lea(edx, Operand(ebx, FrameDescription::frame_content_offset()));
Label pop_loop_header;
__ jmp(&pop_loop_header);
Label pop_loop;
__ bind(&pop_loop);
__ pop(Operand(edx, 0));
__ add(edx, Immediate(sizeof(uint32_t)));
__ bind(&pop_loop_header);
__ cmp(ecx, esp);
__ j(not_equal, &pop_loop);
// Compute the output frame in the deoptimizer.
__ push(eax);
__ PrepareCallCFunction(1, ebx);
__ mov(Operand(esp, 0 * kPointerSize), eax);
{
AllowExternalCallThatCantCauseGC scope(masm());
__ CallCFunction(
ExternalReference::compute_output_frames_function(isolate()), 1);
}
__ pop(eax);
// If frame was dynamically aligned, pop padding.
Label no_padding;
__ cmp(Operand(eax, Deoptimizer::has_alignment_padding_offset()),
Immediate(0));
__ j(equal, &no_padding);
__ pop(ecx);
if (FLAG_debug_code) {
__ cmp(ecx, Immediate(kAlignmentZapValue));
__ Assert(equal, kAlignmentMarkerExpected);
}
__ bind(&no_padding);
// Replace the current frame with the output frames.
Label outer_push_loop, inner_push_loop,
outer_loop_header, inner_loop_header;
// Outer loop state: eax = current FrameDescription**, edx = one past the
// last FrameDescription**.
__ mov(edx, Operand(eax, Deoptimizer::output_count_offset()));
__ mov(eax, Operand(eax, Deoptimizer::output_offset()));
__ lea(edx, Operand(eax, edx, times_4, 0));
__ jmp(&outer_loop_header);
__ bind(&outer_push_loop);
// Inner loop state: ebx = current FrameDescription*, ecx = loop index.
__ mov(ebx, Operand(eax, 0));
__ mov(ecx, Operand(ebx, FrameDescription::frame_size_offset()));
__ jmp(&inner_loop_header);
__ bind(&inner_push_loop);
__ sub(ecx, Immediate(sizeof(uint32_t)));
__ push(Operand(ebx, ecx, times_1, FrameDescription::frame_content_offset()));
__ bind(&inner_loop_header);
__ test(ecx, ecx);
__ j(not_zero, &inner_push_loop);
__ add(eax, Immediate(kPointerSize));
__ bind(&outer_loop_header);
__ cmp(eax, edx);
__ j(below, &outer_push_loop);
// In case of a failed STUB, we have to restore the XMM registers.
for (int i = 0; i < XMMRegister::kMaxNumAllocatableRegisters; ++i) {
XMMRegister xmm_reg = XMMRegister::FromAllocationIndex(i);
int src_offset = i * kDoubleSize + double_regs_offset;
__ movsd(xmm_reg, Operand(ebx, src_offset));
}
// Push state, pc, and continuation from the last output frame.
__ push(Operand(ebx, FrameDescription::state_offset()));
__ push(Operand(ebx, FrameDescription::pc_offset()));
__ push(Operand(ebx, FrameDescription::continuation_offset()));
// Push the registers from the last output frame.
for (int i = 0; i < kNumberOfRegisters; i++) {
int offset = (i * kPointerSize) + FrameDescription::registers_offset();
__ push(Operand(ebx, offset));
}
// Restore the registers from the stack.
__ popad();
// Return to the continuation point.
__ ret(0);
}
void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
// Create a sequence of deoptimization entries.
Label done;
for (int i = 0; i < count(); i++) {
int start = masm()->pc_offset();
USE(start);
__ push_imm32(i);
__ jmp(&done);
DCHECK(masm()->pc_offset() - start == table_entry_size_);
}
__ bind(&done);
}
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 out-of-line constant pool support.
UNREACHABLE();
}
#undef __
} } // namespace v8::internal
#endif // V8_TARGET_ARCH_IA32