root/src/safepoint-table.cc
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DEFINITIONS
This source file includes following definitions.
- HasRegisters
- HasRegisterAt
- FindEntry
- PrintEntry
- PrintBits
- DefinePointerRegister
- DefineSafepoint
- RecordLazyDeoptimizationIndex
- GetCodeOffset
- Emit
- EncodeExceptPC
// Copyright 2011 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "v8.h"
#include "safepoint-table.h"
#include "deoptimizer.h"
#include "disasm.h"
#include "macro-assembler.h"
#include "zone-inl.h"
namespace v8 {
namespace internal {
bool SafepointEntry::HasRegisters() const {
ASSERT(is_valid());
ASSERT(IsAligned(kNumSafepointRegisters, kBitsPerByte));
const int num_reg_bytes = kNumSafepointRegisters >> kBitsPerByteLog2;
for (int i = 0; i < num_reg_bytes; i++) {
if (bits_[i] != SafepointTable::kNoRegisters) return true;
}
return false;
}
bool SafepointEntry::HasRegisterAt(int reg_index) const {
ASSERT(is_valid());
ASSERT(reg_index >= 0 && reg_index < kNumSafepointRegisters);
int byte_index = reg_index >> kBitsPerByteLog2;
int bit_index = reg_index & (kBitsPerByte - 1);
return (bits_[byte_index] & (1 << bit_index)) != 0;
}
SafepointTable::SafepointTable(Code* code) {
ASSERT(code->kind() == Code::OPTIMIZED_FUNCTION);
code_ = code;
Address header = code->instruction_start() + code->safepoint_table_offset();
length_ = Memory::uint32_at(header + kLengthOffset);
entry_size_ = Memory::uint32_at(header + kEntrySizeOffset);
pc_and_deoptimization_indexes_ = header + kHeaderSize;
entries_ = pc_and_deoptimization_indexes_ +
(length_ * kPcAndDeoptimizationIndexSize);
ASSERT(entry_size_ > 0);
STATIC_ASSERT(SafepointEntry::DeoptimizationIndexField::kMax ==
Safepoint::kNoDeoptimizationIndex);
}
SafepointEntry SafepointTable::FindEntry(Address pc) const {
unsigned pc_offset = static_cast<unsigned>(pc - code_->instruction_start());
for (unsigned i = 0; i < length(); i++) {
// TODO(kasperl): Replace the linear search with binary search.
if (GetPcOffset(i) == pc_offset) return GetEntry(i);
}
return SafepointEntry();
}
void SafepointTable::PrintEntry(unsigned index) const {
disasm::NameConverter converter;
SafepointEntry entry = GetEntry(index);
uint8_t* bits = entry.bits();
// Print the stack slot bits.
if (entry_size_ > 0) {
ASSERT(IsAligned(kNumSafepointRegisters, kBitsPerByte));
const int first = kNumSafepointRegisters >> kBitsPerByteLog2;
int last = entry_size_ - 1;
for (int i = first; i < last; i++) PrintBits(bits[i], kBitsPerByte);
int last_bits = code_->stack_slots() - ((last - first) * kBitsPerByte);
PrintBits(bits[last], last_bits);
// Print the registers (if any).
if (!entry.HasRegisters()) return;
for (int j = 0; j < kNumSafepointRegisters; j++) {
if (entry.HasRegisterAt(j)) {
PrintF(" | %s", converter.NameOfCPURegister(j));
}
}
}
}
void SafepointTable::PrintBits(uint8_t byte, int digits) {
ASSERT(digits >= 0 && digits <= kBitsPerByte);
for (int i = 0; i < digits; i++) {
PrintF("%c", ((byte & (1 << i)) == 0) ? '0' : '1');
}
}
void Safepoint::DefinePointerRegister(Register reg, Zone* zone) {
registers_->Add(reg.code(), zone);
}
Safepoint SafepointTableBuilder::DefineSafepoint(
Assembler* assembler,
Safepoint::Kind kind,
int arguments,
Safepoint::DeoptMode deopt_mode) {
ASSERT(arguments >= 0);
DeoptimizationInfo info;
info.pc = assembler->pc_offset();
info.arguments = arguments;
info.has_doubles = (kind & Safepoint::kWithDoubles);
deoptimization_info_.Add(info, zone_);
deopt_index_list_.Add(Safepoint::kNoDeoptimizationIndex, zone_);
if (deopt_mode == Safepoint::kNoLazyDeopt) {
last_lazy_safepoint_ = deopt_index_list_.length();
}
indexes_.Add(new(zone_) ZoneList<int>(8, zone_), zone_);
registers_.Add((kind & Safepoint::kWithRegisters)
? new(zone_) ZoneList<int>(4, zone_)
: NULL,
zone_);
return Safepoint(indexes_.last(), registers_.last());
}
void SafepointTableBuilder::RecordLazyDeoptimizationIndex(int index) {
while (last_lazy_safepoint_ < deopt_index_list_.length()) {
deopt_index_list_[last_lazy_safepoint_++] = index;
}
}
unsigned SafepointTableBuilder::GetCodeOffset() const {
ASSERT(emitted_);
return offset_;
}
void SafepointTableBuilder::Emit(Assembler* assembler, int bits_per_entry) {
// For lazy deoptimization we need space to patch a call after every call.
// Ensure there is always space for such patching, even if the code ends
// in a call.
int target_offset = assembler->pc_offset() + Deoptimizer::patch_size();
while (assembler->pc_offset() < target_offset) {
assembler->nop();
}
// Make sure the safepoint table is properly aligned. Pad with nops.
assembler->Align(kIntSize);
assembler->RecordComment(";;; Safepoint table.");
offset_ = assembler->pc_offset();
// Take the register bits into account.
bits_per_entry += kNumSafepointRegisters;
// Compute the number of bytes per safepoint entry.
int bytes_per_entry =
RoundUp(bits_per_entry, kBitsPerByte) >> kBitsPerByteLog2;
// Emit the table header.
int length = deoptimization_info_.length();
assembler->dd(length);
assembler->dd(bytes_per_entry);
// Emit sorted table of pc offsets together with deoptimization indexes.
for (int i = 0; i < length; i++) {
assembler->dd(deoptimization_info_[i].pc);
assembler->dd(EncodeExceptPC(deoptimization_info_[i],
deopt_index_list_[i]));
}
// Emit table of bitmaps.
ZoneList<uint8_t> bits(bytes_per_entry, zone_);
for (int i = 0; i < length; i++) {
ZoneList<int>* indexes = indexes_[i];
ZoneList<int>* registers = registers_[i];
bits.Clear();
bits.AddBlock(0, bytes_per_entry, zone_);
// Run through the registers (if any).
ASSERT(IsAligned(kNumSafepointRegisters, kBitsPerByte));
if (registers == NULL) {
const int num_reg_bytes = kNumSafepointRegisters >> kBitsPerByteLog2;
for (int j = 0; j < num_reg_bytes; j++) {
bits[j] = SafepointTable::kNoRegisters;
}
} else {
for (int j = 0; j < registers->length(); j++) {
int index = registers->at(j);
ASSERT(index >= 0 && index < kNumSafepointRegisters);
int byte_index = index >> kBitsPerByteLog2;
int bit_index = index & (kBitsPerByte - 1);
bits[byte_index] |= (1 << bit_index);
}
}
// Run through the indexes and build a bitmap.
for (int j = 0; j < indexes->length(); j++) {
int index = bits_per_entry - 1 - indexes->at(j);
int byte_index = index >> kBitsPerByteLog2;
int bit_index = index & (kBitsPerByte - 1);
bits[byte_index] |= (1U << bit_index);
}
// Emit the bitmap for the current entry.
for (int k = 0; k < bytes_per_entry; k++) {
assembler->db(bits[k]);
}
}
emitted_ = true;
}
uint32_t SafepointTableBuilder::EncodeExceptPC(const DeoptimizationInfo& info,
unsigned index) {
uint32_t encoding = SafepointEntry::DeoptimizationIndexField::encode(index);
encoding |= SafepointEntry::ArgumentsField::encode(info.arguments);
encoding |= SafepointEntry::SaveDoublesField::encode(info.has_doubles);
return encoding;
}
} } // namespace v8::internal