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// Copyright 2011 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 {
int Deoptimizer::patch_size() {
const int kCallInstructionSizeInWords = 4;
return kCallInstructionSizeInWords * Assembler::kInstrSize;
}
void Deoptimizer::EnsureRelocSpaceForLazyDeoptimization(Handle<Code> code) {
// Empty because there is no need for relocation information for the code
// patching in Deoptimizer::PatchCodeForDeoptimization below.
}
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()->break_(0xCC);
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()->break_(0xCC);
}
}
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);
int call_size_in_bytes = MacroAssembler::CallSize(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, CodeStubDescriptor* 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(a0.code(), params);
output_frame->SetRegister(a1.code(), handler);
}
void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
for (int i = 0; i < DoubleRegister::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 MIPS 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::TableEntryGenerator::Generate() {
GeneratePrologue();
// 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() | ra.bit();
const int kDoubleRegsSize =
kDoubleSize * FPURegister::kMaxNumAllocatableRegisters;
// Save all FPU registers before messing with them.
__ Subu(sp, sp, Operand(kDoubleRegsSize));
for (int i = 0; i < FPURegister::kMaxNumAllocatableRegisters; ++i) {
FPURegister fpu_reg = FPURegister::FromAllocationIndex(i);
int offset = i * kDoubleSize;
__ sdc1(fpu_reg, MemOperand(sp, offset));
}
// Push saved_regs (needed to populate FrameDescription::registers_).
// Leave gaps for other registers.
__ Subu(sp, sp, kNumberOfRegisters * kPointerSize);
for (int16_t i = kNumberOfRegisters - 1; i >= 0; i--) {
if ((saved_regs & (1 << i)) != 0) {
__ sw(ToRegister(i), MemOperand(sp, kPointerSize * i));
}
}
__ li(a2, Operand(ExternalReference(Isolate::kCEntryFPAddress, isolate())));
__ sw(fp, MemOperand(a2));
const int kSavedRegistersAreaSize =
(kNumberOfRegisters * kPointerSize) + kDoubleRegsSize;
// Get the bailout id from the stack.
__ lw(a2, MemOperand(sp, kSavedRegistersAreaSize));
// Get the address of the location in the code object (a3) (return
// address for lazy deoptimization) and compute the fp-to-sp delta in
// register t0.
__ mov(a3, ra);
// Correct one word for bailout id.
__ Addu(t0, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
__ Subu(t0, fp, t0);
// Allocate a new deoptimizer object.
// Pass four arguments in a0 to a3 and fifth & sixth arguments on stack.
__ PrepareCallCFunction(6, t1);
__ lw(a0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
__ li(a1, Operand(type())); // bailout type,
// a2: bailout id already loaded.
// a3: code address or 0 already loaded.
__ sw(t0, CFunctionArgumentOperand(5)); // Fp-to-sp delta.
__ li(t1, Operand(ExternalReference::isolate_address(isolate())));
__ sw(t1, CFunctionArgumentOperand(6)); // Isolate.
// Call Deoptimizer::New().
{
AllowExternalCallThatCantCauseGC scope(masm());
__ CallCFunction(ExternalReference::new_deoptimizer_function(isolate()), 6);
}
// Preserve "deoptimizer" object in register v0 and get the input
// frame descriptor pointer to a1 (deoptimizer->input_);
// Move deopt-obj to a0 for call to Deoptimizer::ComputeOutputFrames() below.
__ mov(a0, v0);
__ lw(a1, MemOperand(v0, 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();
if ((saved_regs & (1 << i)) != 0) {
__ lw(a2, MemOperand(sp, i * kPointerSize));
__ sw(a2, MemOperand(a1, offset));
} else if (FLAG_debug_code) {
__ li(a2, kDebugZapValue);
__ sw(a2, MemOperand(a1, offset));
}
}
int double_regs_offset = FrameDescription::double_registers_offset();
// Copy FPU registers to
// double_registers_[DoubleRegister::kNumAllocatableRegisters]
for (int i = 0; i < FPURegister::NumAllocatableRegisters(); ++i) {
int dst_offset = i * kDoubleSize + double_regs_offset;
int src_offset = i * kDoubleSize + kNumberOfRegisters * kPointerSize;
__ ldc1(f0, MemOperand(sp, src_offset));
__ sdc1(f0, MemOperand(a1, dst_offset));
}
// Remove the bailout id and the saved registers from the stack.
__ Addu(sp, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
// Compute a pointer to the unwinding limit in register a2; that is
// the first stack slot not part of the input frame.
__ lw(a2, MemOperand(a1, FrameDescription::frame_size_offset()));
__ Addu(a2, a2, 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.
__ Addu(a3, a1, Operand(FrameDescription::frame_content_offset()));
Label pop_loop;
Label pop_loop_header;
__ BranchShort(&pop_loop_header);
__ bind(&pop_loop);
__ pop(t0);
__ sw(t0, MemOperand(a3, 0));
__ addiu(a3, a3, sizeof(uint32_t));
__ bind(&pop_loop_header);
__ BranchShort(&pop_loop, ne, a2, Operand(sp));
// Compute the output frame in the deoptimizer.
__ push(a0); // Preserve deoptimizer object across call.
// a0: deoptimizer object; a1: scratch.
__ PrepareCallCFunction(1, a1);
// Call Deoptimizer::ComputeOutputFrames().
{
AllowExternalCallThatCantCauseGC scope(masm());
__ CallCFunction(
ExternalReference::compute_output_frames_function(isolate()), 1);
}
__ pop(a0); // 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: t0 = current "FrameDescription** output_",
// a1 = one past the last FrameDescription**.
__ lw(a1, MemOperand(a0, Deoptimizer::output_count_offset()));
__ lw(t0, MemOperand(a0, Deoptimizer::output_offset())); // t0 is output_.
__ sll(a1, a1, kPointerSizeLog2); // Count to offset.
__ addu(a1, t0, a1); // a1 = one past the last FrameDescription**.
__ jmp(&outer_loop_header);
__ bind(&outer_push_loop);
// Inner loop state: a2 = current FrameDescription*, a3 = loop index.
__ lw(a2, MemOperand(t0, 0)); // output_[ix]
__ lw(a3, MemOperand(a2, FrameDescription::frame_size_offset()));
__ jmp(&inner_loop_header);
__ bind(&inner_push_loop);
__ Subu(a3, a3, Operand(sizeof(uint32_t)));
__ Addu(t2, a2, Operand(a3));
__ lw(t3, MemOperand(t2, FrameDescription::frame_content_offset()));
__ push(t3);
__ bind(&inner_loop_header);
__ BranchShort(&inner_push_loop, ne, a3, Operand(zero_reg));
__ Addu(t0, t0, Operand(kPointerSize));
__ bind(&outer_loop_header);
__ BranchShort(&outer_push_loop, lt, t0, Operand(a1));
__ lw(a1, MemOperand(a0, Deoptimizer::input_offset()));
for (int i = 0; i < FPURegister::kMaxNumAllocatableRegisters; ++i) {
const FPURegister fpu_reg = FPURegister::FromAllocationIndex(i);
int src_offset = i * kDoubleSize + double_regs_offset;
__ ldc1(fpu_reg, MemOperand(a1, src_offset));
}
// Push state, pc, and continuation from the last output frame.
__ lw(t2, MemOperand(a2, FrameDescription::state_offset()));
__ push(t2);
__ lw(t2, MemOperand(a2, FrameDescription::pc_offset()));
__ push(t2);
__ lw(t2, MemOperand(a2, FrameDescription::continuation_offset()));
__ push(t2);
// Technically restoring 'at' should work unless zero_reg is also restored
// but it's safer to check for this.
DCHECK(!(at.bit() & restored_regs));
// Restore the registers from the last output frame.
__ mov(at, a2);
for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
int offset = (i * kPointerSize) + FrameDescription::registers_offset();
if ((restored_regs & (1 << i)) != 0) {
__ lw(ToRegister(i), MemOperand(at, offset));
}
}
__ InitializeRootRegister();
__ pop(at); // Get continuation, leave pc on stack.
__ pop(ra);
__ Jump(at);
__ stop("Unreachable.");
}
// Maximum size of a table entry generated below.
const int Deoptimizer::table_entry_size_ = 2 * Assembler::kInstrSize;
void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm());
// Create a sequence of deoptimization entries.
// Note that registers are still live when jumping to an entry.
Label table_start, done, done_special, trampoline_jump;
__ bind(&table_start);
int kMaxEntriesBranchReach = (1 << (kImm16Bits - 2))/
(table_entry_size_ / Assembler::kInstrSize);
if (count() <= kMaxEntriesBranchReach) {
// Common case.
for (int i = 0; i < count(); i++) {
Label start;
__ bind(&start);
DCHECK(is_int16(i));
__ Branch(USE_DELAY_SLOT, &done); // Expose delay slot.
__ li(at, i); // In the delay slot.
DCHECK_EQ(table_entry_size_, masm()->SizeOfCodeGeneratedSince(&start));
}
DCHECK_EQ(masm()->SizeOfCodeGeneratedSince(&table_start),
count() * table_entry_size_);
__ bind(&done);
__ Push(at);
} else {
// Uncommon case, the branch cannot reach.
// Create mini trampoline and adjust id constants to get proper value at
// the end of table.
for (int i = kMaxEntriesBranchReach; i > 1; i--) {
Label start;
__ bind(&start);
DCHECK(is_int16(i));
__ Branch(USE_DELAY_SLOT, &trampoline_jump); // Expose delay slot.
__ li(at, - i); // In the delay slot.
DCHECK_EQ(table_entry_size_, masm()->SizeOfCodeGeneratedSince(&start));
}
// Entry with id == kMaxEntriesBranchReach - 1.
__ bind(&trampoline_jump);
__ Branch(USE_DELAY_SLOT, &done_special);
__ li(at, -1);
for (int i = kMaxEntriesBranchReach ; i < count(); i++) {
Label start;
__ bind(&start);
DCHECK(is_int16(i));
__ Branch(USE_DELAY_SLOT, &done); // Expose delay slot.
__ li(at, i); // In the delay slot.
}
DCHECK_EQ(masm()->SizeOfCodeGeneratedSince(&table_start),
count() * table_entry_size_);
__ bind(&done_special);
__ addiu(at, at, kMaxEntriesBranchReach);
__ bind(&done);
__ Push(at);
}
}
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