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// 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/codegen.h"
#include "src/deoptimizer.h"
#include "src/full-codegen/full-codegen.h"
#include "src/register-configuration.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::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(isolate, 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(isolate, 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::CallDeoptimizerSize();
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(isolate, call_address, call_size_in_words);
patcher.masm()->CallDeoptimizer(deopt_entry);
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::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(r0.code(), params);
output_frame->SetRegister(r1.code(), handler);
}
void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
for (int i = 0; i < DwVfpRegister::kMaxNumRegisters; ++i) {
Float64 double_value = input_->GetDoubleRegister(i);
output_frame->SetDoubleRegister(i, double_value);
}
}
#define __ masm()->
// This code tries to be close to ia32 code so that any changes can be
// easily ported.
void Deoptimizer::TableEntryGenerator::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::kMaxNumRegisters;
// Save all allocatable VFP registers before messing with them.
DCHECK(kDoubleRegZero.code() == 14);
DCHECK(kScratchDoubleReg.code() == 15);
{
// We use a run-time check for VFP32DREGS.
CpuFeatureScope scope(masm(), VFP32DREGS,
CpuFeatureScope::kDontCheckSupported);
// Check CPU flags for number of registers, setting the Z condition flag.
__ CheckFor32DRegs(ip);
// Push registers d0-d15, 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, d15);
}
// 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());
__ mov(ip, Operand(ExternalReference(Isolate::kCEntryFPAddress, isolate())));
__ str(fp, MemOperand(ip));
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);
__ mov(r0, Operand(0));
Label context_check;
__ ldr(r1, MemOperand(fp, CommonFrameConstants::kContextOrFrameTypeOffset));
__ JumpIfSmi(r1, &context_check);
__ ldr(r0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
__ bind(&context_check);
__ 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();
const RegisterConfiguration* config = RegisterConfiguration::Crankshaft();
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;
__ 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).
__ ldr(sp, MemOperand(r0, 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: 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);
__ ldr(r1, MemOperand(r0, Deoptimizer::input_offset()));
for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
int code = config->GetAllocatableDoubleCode(i);
DwVfpRegister reg = DwVfpRegister::from_code(code);
int src_offset = code * kDoubleSize + double_regs_offset;
__ vldr(reg, r1, src_offset);
}
// 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.
// We need to be able to generate immediates up to kMaxNumberOfEntries. On
// ARMv7, we can use movw (with a maximum immediate of 0xffff). On ARMv6, we
// need two instructions.
STATIC_ASSERT((kMaxNumberOfEntries - 1) <= 0xffff);
if (CpuFeatures::IsSupported(ARMv7)) {
CpuFeatureScope scope(masm(), ARMv7);
Label done;
for (int i = 0; i < count(); i++) {
int start = masm()->pc_offset();
USE(start);
__ movw(ip, i);
__ b(&done);
DCHECK_EQ(table_entry_size_, masm()->pc_offset() - start);
}
__ bind(&done);
} else {
// We want to keep table_entry_size_ == 8 (since this is the common case),
// but we need two instructions to load most immediates over 0xff. To handle
// this, we set the low byte in the main table, and then set the high byte
// in a separate table if necessary.
Label high_fixes[256];
int high_fix_max = (count() - 1) >> 8;
DCHECK_GT(arraysize(high_fixes), static_cast<size_t>(high_fix_max));
for (int i = 0; i < count(); i++) {
int start = masm()->pc_offset();
USE(start);
__ mov(ip, Operand(i & 0xff)); // Set the low byte.
__ b(&high_fixes[i >> 8]); // Jump to the secondary table.
DCHECK_EQ(table_entry_size_, masm()->pc_offset() - start);
}
// Generate the secondary table, to set the high byte.
for (int high = 1; high <= high_fix_max; high++) {
__ bind(&high_fixes[high]);
__ orr(ip, ip, Operand(high << 8));
// If this isn't the last entry, emit a branch to the end of the table.
// The last entry can just fall through.
if (high < high_fix_max) __ b(&high_fixes[0]);
}
// Bind high_fixes[0] last, for indices like 0x00**. This case requires no
// fix-up, so for (common) small tables we can jump here, then just fall
// through with no additional branch.
__ bind(&high_fixes[0]);
}
__ 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_embedded_constant_pool);
SetFrameSlot(offset, value);
}
#undef __
} // namespace internal
} // namespace v8