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cobalt / cobalt / 0e7d696c3ce6a2ef566d0fabc20213b6a651f942 / . / src / third_party / v8 / src / wasm / wasm-code-manager.cc
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// Copyright 2017 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/wasm/wasm-code-manager.h"
#include <iomanip>
#include "src/base/build_config.h"
#include "src/base/iterator.h"
#include "src/base/macros.h"
#include "src/base/platform/platform.h"
#include "src/base/small-vector.h"
#include "src/codegen/assembler-inl.h"
#include "src/codegen/macro-assembler-inl.h"
#include "src/codegen/macro-assembler.h"
#include "src/common/globals.h"
#include "src/diagnostics/disassembler.h"
#include "src/logging/counters.h"
#include "src/logging/log.h"
#include "src/objects/objects-inl.h"
#include "src/snapshot/embedded/embedded-data.h"
#include "src/utils/ostreams.h"
#include "src/utils/vector.h"
#include "src/wasm/code-space-access.h"
#include "src/wasm/compilation-environment.h"
#include "src/wasm/function-compiler.h"
#include "src/wasm/jump-table-assembler.h"
#include "src/wasm/module-compiler.h"
#include "src/wasm/wasm-debug.h"
#include "src/wasm/wasm-import-wrapper-cache.h"
#include "src/wasm/wasm-module-sourcemap.h"
#include "src/wasm/wasm-module.h"
#include "src/wasm/wasm-objects-inl.h"
#include "src/wasm/wasm-objects.h"
#if defined(V8_OS_WIN64)
#include "src/diagnostics/unwinding-info-win64.h"
#endif // V8_OS_WIN64
#define TRACE_HEAP(...) \
do { \
if (FLAG_trace_wasm_native_heap) PrintF(__VA_ARGS__); \
} while (false)
namespace v8 {
namespace internal {
namespace wasm {
using trap_handler::ProtectedInstructionData;
#if defined(V8_OS_MACOSX) && defined(V8_HOST_ARCH_ARM64)
thread_local int CodeSpaceWriteScope::code_space_write_nesting_level_ = 0;
#endif
base::AddressRegion DisjointAllocationPool::Merge(
base::AddressRegion new_region) {
// Find the possible insertion position by identifying the first region whose
// start address is not less than that of {new_region}. Since there cannot be
// any overlap between regions, this also means that the start of {above} is
// bigger or equal than the *end* of {new_region}.
auto above = regions_.lower_bound(new_region);
DCHECK(above == regions_.end() || above->begin() >= new_region.end());
// Check whether to merge with {above}.
if (above != regions_.end() && new_region.end() == above->begin()) {
base::AddressRegion merged_region{new_region.begin(),
new_region.size() + above->size()};
DCHECK_EQ(merged_region.end(), above->end());
// Check whether to also merge with the region below.
if (above != regions_.begin()) {
auto below = above;
--below;
if (below->end() == new_region.begin()) {
merged_region = {below->begin(), below->size() + merged_region.size()};
regions_.erase(below);
}
}
auto insert_pos = regions_.erase(above);
regions_.insert(insert_pos, merged_region);
return merged_region;
}
// No element below, and not adjavent to {above}: insert and done.
if (above == regions_.begin()) {
regions_.insert(above, new_region);
return new_region;
}
auto below = above;
--below;
// Consistency check:
DCHECK(above == regions_.end() || below->end() < above->begin());
// Adjacent to {below}: merge and done.
if (below->end() == new_region.begin()) {
base::AddressRegion merged_region{below->begin(),
below->size() + new_region.size()};
DCHECK_EQ(merged_region.end(), new_region.end());
regions_.erase(below);
regions_.insert(above, merged_region);
return merged_region;
}
// Not adjacent to any existing region: insert between {below} and {above}.
DCHECK_LT(below->end(), new_region.begin());
regions_.insert(above, new_region);
return new_region;
}
base::AddressRegion DisjointAllocationPool::Allocate(size_t size) {
return AllocateInRegion(size,
{kNullAddress, std::numeric_limits<size_t>::max()});
}
base::AddressRegion DisjointAllocationPool::AllocateInRegion(
size_t size, base::AddressRegion region) {
// Get an iterator to the first contained region whose start address is not
// smaller than the start address of {region}. Start the search from the
// region one before that (the last one whose start address is smaller).
auto it = regions_.lower_bound(region);
if (it != regions_.begin()) --it;
for (auto end = regions_.end(); it != end; ++it) {
base::AddressRegion overlap = it->GetOverlap(region);
if (size > overlap.size()) continue;
base::AddressRegion ret{overlap.begin(), size};
base::AddressRegion old = *it;
auto insert_pos = regions_.erase(it);
if (size == old.size()) {
// We use the full region --> nothing to add back.
} else if (ret.begin() == old.begin()) {
// We return a region at the start --> shrink old region from front.
regions_.insert(insert_pos, {old.begin() + size, old.size() - size});
} else if (ret.end() == old.end()) {
// We return a region at the end --> shrink remaining region.
regions_.insert(insert_pos, {old.begin(), old.size() - size});
} else {
// We return something in the middle --> split the remaining region
// (insert the region with smaller address first).
regions_.insert(insert_pos, {old.begin(), ret.begin() - old.begin()});
regions_.insert(insert_pos, {ret.end(), old.end() - ret.end()});
}
return ret;
}
return {};
}
Address WasmCode::constant_pool() const {
if (FLAG_enable_embedded_constant_pool) {
if (constant_pool_offset_ < code_comments_offset_) {
return instruction_start() + constant_pool_offset_;
}
}
return kNullAddress;
}
Address WasmCode::handler_table() const {
return instruction_start() + handler_table_offset_;
}
int WasmCode::handler_table_size() const {
DCHECK_GE(constant_pool_offset_, handler_table_offset_);
return static_cast<int>(constant_pool_offset_ - handler_table_offset_);
}
Address WasmCode::code_comments() const {
return instruction_start() + code_comments_offset_;
}
int WasmCode::code_comments_size() const {
DCHECK_GE(unpadded_binary_size_, code_comments_offset_);
return static_cast<int>(unpadded_binary_size_ - code_comments_offset_);
}
std::unique_ptr<const byte[]> WasmCode::ConcatenateBytes(
std::initializer_list<Vector<const byte>> vectors) {
size_t total_size = 0;
for (auto& vec : vectors) total_size += vec.size();
// Use default-initialization (== no initialization).
byte* ptr = new byte[total_size];
for (auto& vec : vectors) {
if (vec.empty()) continue; // Avoid nullptr in {memcpy}.
memcpy(ptr, vec.begin(), vec.size());
ptr += vec.size();
}
return std::unique_ptr<const byte[]>(ptr);
}
void WasmCode::RegisterTrapHandlerData() {
DCHECK(!has_trap_handler_index());
if (kind() != WasmCode::kFunction) return;
if (protected_instructions_size_ == 0) return;
Address base = instruction_start();
size_t size = instructions().size();
auto protected_instruction_data = this->protected_instructions();
const int index =
RegisterHandlerData(base, size, protected_instruction_data.size(),
protected_instruction_data.begin());
// TODO(eholk): if index is negative, fail.
CHECK_LE(0, index);
set_trap_handler_index(index);
DCHECK(has_trap_handler_index());
}
bool WasmCode::ShouldBeLogged(Isolate* isolate) {
// The return value is cached in {WasmEngine::IsolateData::log_codes}. Ensure
// to call {WasmEngine::EnableCodeLogging} if this return value would change
// for any isolate. Otherwise we might lose code events.
return isolate->logger()->is_listening_to_code_events() ||
isolate->code_event_dispatcher()->IsListeningToCodeEvents() ||
isolate->is_profiling();
}
void WasmCode::LogCode(Isolate* isolate) const {
DCHECK(ShouldBeLogged(isolate));
if (IsAnonymous()) return;
ModuleWireBytes wire_bytes(native_module()->wire_bytes());
WireBytesRef name_ref =
native_module()->module()->lazily_generated_names.LookupFunctionName(
wire_bytes, index(),
VectorOf(native_module()->module()->export_table));
WasmName name = wire_bytes.GetNameOrNull(name_ref);
const WasmDebugSymbols& debug_symbols =
native_module()->module()->debug_symbols;
auto load_wasm_source_map = isolate->wasm_load_source_map_callback();
auto source_map = native_module()->GetWasmSourceMap();
if (!source_map && debug_symbols.type == WasmDebugSymbols::Type::SourceMap &&
!debug_symbols.external_url.is_empty() && load_wasm_source_map) {
WasmName external_url =
wire_bytes.GetNameOrNull(debug_symbols.external_url);
std::string external_url_string(external_url.data(), external_url.size());
HandleScope scope(isolate);
v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate);
Local<v8::String> source_map_str =
load_wasm_source_map(v8_isolate, external_url_string.c_str());
native_module()->SetWasmSourceMap(
std::make_unique<WasmModuleSourceMap>(v8_isolate, source_map_str));
}
std::string name_buffer;
if (kind() == kWasmToJsWrapper) {
name_buffer = "wasm-to-js:";
size_t prefix_len = name_buffer.size();
constexpr size_t kMaxSigLength = 128;
name_buffer.resize(prefix_len + kMaxSigLength);
const FunctionSig* sig = native_module()->module()->functions[index_].sig;
size_t sig_length =
PrintSignature(VectorOf(&name_buffer[prefix_len], kMaxSigLength), sig);
name_buffer.resize(prefix_len + sig_length);
// If the import has a name, also append that (separated by "-").
if (!name.empty()) {
name_buffer += '-';
name_buffer.append(name.begin(), name.size());
}
name = VectorOf(name_buffer);
} else if (name.empty()) {
name_buffer.resize(32);
name_buffer.resize(
SNPrintF(VectorOf(&name_buffer.front(), name_buffer.size()),
"wasm-function[%d]", index()));
name = VectorOf(name_buffer);
}
PROFILE(isolate,
CodeCreateEvent(CodeEventListener::FUNCTION_TAG, this, name));
if (!source_positions().empty()) {
LOG_CODE_EVENT(isolate, CodeLinePosInfoRecordEvent(instruction_start(),
source_positions()));
}
}
void WasmCode::Validate() const {
#ifdef DEBUG
// Scope for foreign WasmCode pointers.
WasmCodeRefScope code_ref_scope;
// We expect certain relocation info modes to never appear in {WasmCode}
// objects or to be restricted to a small set of valid values. Hence the
// iteration below does not use a mask, but visits all relocation data.
for (RelocIterator it(instructions(), reloc_info(), constant_pool());
!it.done(); it.next()) {
RelocInfo::Mode mode = it.rinfo()->rmode();
switch (mode) {
case RelocInfo::WASM_CALL: {
Address target = it.rinfo()->wasm_call_address();
WasmCode* code = native_module_->Lookup(target);
CHECK_NOT_NULL(code);
CHECK_EQ(WasmCode::kJumpTable, code->kind());
CHECK(code->contains(target));
break;
}
case RelocInfo::WASM_STUB_CALL: {
Address target = it.rinfo()->wasm_stub_call_address();
WasmCode* code = native_module_->Lookup(target);
CHECK_NOT_NULL(code);
CHECK_EQ(WasmCode::kJumpTable, code->kind());
CHECK(code->contains(target));
break;
}
case RelocInfo::INTERNAL_REFERENCE:
case RelocInfo::INTERNAL_REFERENCE_ENCODED: {
Address target = it.rinfo()->target_internal_reference();
CHECK(contains(target));
break;
}
case RelocInfo::EXTERNAL_REFERENCE:
case RelocInfo::CONST_POOL:
case RelocInfo::VENEER_POOL:
// These are OK to appear.
break;
default:
FATAL("Unexpected mode: %d", mode);
}
}
#endif
}
void WasmCode::MaybePrint(const char* name) const {
// Determines whether flags want this code to be printed.
bool function_index_matches =
(!IsAnonymous() &&
FLAG_print_wasm_code_function_index == static_cast<int>(index()));
if (FLAG_print_code ||
(kind() == kFunction ? (FLAG_print_wasm_code || function_index_matches)
: FLAG_print_wasm_stub_code)) {
Print(name);
}
}
void WasmCode::Print(const char* name) const {
StdoutStream os;
os << "--- WebAssembly code ---\n";
Disassemble(name, os);
if (native_module_->HasDebugInfo()) {
if (auto* debug_side_table =
native_module_->GetDebugInfo()->GetDebugSideTableIfExists(this)) {
debug_side_table->Print(os);
}
}
os << "--- End code ---\n";
}
void WasmCode::Disassemble(const char* name, std::ostream& os,
Address current_pc) const {
if (name) os << "name: " << name << "\n";
if (!IsAnonymous()) os << "index: " << index() << "\n";
os << "kind: " << GetWasmCodeKindAsString(kind()) << "\n";
os << "compiler: " << (is_liftoff() ? "Liftoff" : "TurboFan") << "\n";
size_t padding = instructions().size() - unpadded_binary_size_;
os << "Body (size = " << instructions().size() << " = "
<< unpadded_binary_size_ << " + " << padding << " padding)\n";
#ifdef ENABLE_DISASSEMBLER
int instruction_size = unpadded_binary_size_;
if (constant_pool_offset_ < instruction_size) {
instruction_size = constant_pool_offset_;
}
if (safepoint_table_offset_ && safepoint_table_offset_ < instruction_size) {
instruction_size = safepoint_table_offset_;
}
if (handler_table_offset_ < instruction_size) {
instruction_size = handler_table_offset_;
}
DCHECK_LT(0, instruction_size);
os << "Instructions (size = " << instruction_size << ")\n";
Disassembler::Decode(nullptr, &os, instructions().begin(),
instructions().begin() + instruction_size,
CodeReference(this), current_pc);
os << "\n";
if (handler_table_size() > 0) {
HandlerTable table(this);
os << "Exception Handler Table (size = " << table.NumberOfReturnEntries()
<< "):\n";
table.HandlerTableReturnPrint(os);
os << "\n";
}
if (protected_instructions_size_ > 0) {
os << "Protected instructions:\n pc offset land pad\n";
for (auto& data : protected_instructions()) {
os << std::setw(10) << std::hex << data.instr_offset << std::setw(10)
<< std::hex << data.landing_offset << "\n";
}
os << "\n";
}
if (!source_positions().empty()) {
os << "Source positions:\n pc offset position\n";
for (SourcePositionTableIterator it(source_positions()); !it.done();
it.Advance()) {
os << std::setw(10) << std::hex << it.code_offset() << std::dec
<< std::setw(10) << it.source_position().ScriptOffset()
<< (it.is_statement() ? " statement" : "") << "\n";
}
os << "\n";
}
if (safepoint_table_offset_ > 0) {
SafepointTable table(this);
os << "Safepoints (size = " << table.size() << ")\n";
for (uint32_t i = 0; i < table.length(); i++) {
uintptr_t pc_offset = table.GetPcOffset(i);
os << reinterpret_cast<const void*>(instruction_start() + pc_offset);
os << std::setw(6) << std::hex << pc_offset << " " << std::dec;
table.PrintEntry(i, os);
os << " (sp -> fp)";
SafepointEntry entry = table.GetEntry(i);
if (entry.trampoline_pc() != -1) {
os << " trampoline: " << std::hex << entry.trampoline_pc() << std::dec;
}
if (entry.has_deoptimization_index()) {
os << " deopt: " << std::setw(6) << entry.deoptimization_index();
}
os << "\n";
}
os << "\n";
}
os << "RelocInfo (size = " << reloc_info().size() << ")\n";
for (RelocIterator it(instructions(), reloc_info(), constant_pool());
!it.done(); it.next()) {
it.rinfo()->Print(nullptr, os);
}
os << "\n";
if (code_comments_size() > 0) {
PrintCodeCommentsSection(os, code_comments(), code_comments_size());
}
#endif // ENABLE_DISASSEMBLER
}
const char* GetWasmCodeKindAsString(WasmCode::Kind kind) {
switch (kind) {
case WasmCode::kFunction:
return "wasm function";
case WasmCode::kWasmToCapiWrapper:
return "wasm-to-capi";
case WasmCode::kWasmToJsWrapper:
return "wasm-to-js";
case WasmCode::kJumpTable:
return "jump table";
}
return "unknown kind";
}
WasmCode::~WasmCode() {
if (has_trap_handler_index()) {
trap_handler::ReleaseHandlerData(trap_handler_index());
}
}
V8_WARN_UNUSED_RESULT bool WasmCode::DecRefOnPotentiallyDeadCode() {
if (native_module_->engine()->AddPotentiallyDeadCode(this)) {
// The code just became potentially dead. The ref count we wanted to
// decrement is now transferred to the set of potentially dead code, and
// will be decremented when the next GC is run.
return false;
}
// If we reach here, the code was already potentially dead. Decrement the ref
// count, and return true if it drops to zero.
return DecRefOnDeadCode();
}
// static
void WasmCode::DecrementRefCount(Vector<WasmCode* const> code_vec) {
// Decrement the ref counter of all given code objects. Keep the ones whose
// ref count drops to zero.
WasmEngine::DeadCodeMap dead_code;
WasmEngine* engine = nullptr;
for (WasmCode* code : code_vec) {
if (!code->DecRef()) continue; // Remaining references.
dead_code[code->native_module()].push_back(code);
if (!engine) engine = code->native_module()->engine();
DCHECK_EQ(engine, code->native_module()->engine());
}
DCHECK_EQ(dead_code.empty(), engine == nullptr);
if (engine) engine->FreeDeadCode(dead_code);
}
int WasmCode::GetSourcePositionBefore(int offset) {
int position = kNoSourcePosition;
for (SourcePositionTableIterator iterator(source_positions());
!iterator.done() && iterator.code_offset() < offset;
iterator.Advance()) {
position = iterator.source_position().ScriptOffset();
}
return position;
}
WasmCodeAllocator::OptionalLock::~OptionalLock() {
if (allocator_) allocator_->mutex_.Unlock();
}
void WasmCodeAllocator::OptionalLock::Lock(WasmCodeAllocator* allocator) {
DCHECK(!is_locked());
allocator_ = allocator;
allocator->mutex_.Lock();
}
// static
constexpr size_t WasmCodeAllocator::kMaxCodeSpaceSize;
WasmCodeAllocator::WasmCodeAllocator(WasmCodeManager* code_manager,
VirtualMemory code_space,
std::shared_ptr<Counters> async_counters)
: code_manager_(code_manager),
free_code_space_(code_space.region()),
async_counters_(std::move(async_counters)) {
owned_code_space_.reserve(4);
owned_code_space_.emplace_back(std::move(code_space));
async_counters_->wasm_module_num_code_spaces()->AddSample(1);
}
WasmCodeAllocator::~WasmCodeAllocator() {
code_manager_->FreeNativeModule(VectorOf(owned_code_space_),
committed_code_space());
}
void WasmCodeAllocator::Init(NativeModule* native_module) {
DCHECK_EQ(1, owned_code_space_.size());
native_module->AddCodeSpace(owned_code_space_[0].region(), {});
}
namespace {
// On Windows, we cannot commit a region that straddles different reservations
// of virtual memory. Because we bump-allocate, and because, if we need more
// memory, we append that memory at the end of the owned_code_space_ list, we
// traverse that list in reverse order to find the reservation(s) that guide how
// to chunk the region to commit.
#if V8_OS_WIN
constexpr bool kNeedsToSplitRangeByReservations = true;
#else
constexpr bool kNeedsToSplitRangeByReservations = false;
#endif
base::SmallVector<base::AddressRegion, 1> SplitRangeByReservationsIfNeeded(
base::AddressRegion range,
const std::vector<VirtualMemory>& owned_code_space) {
if (!kNeedsToSplitRangeByReservations) return {range};
base::SmallVector<base::AddressRegion, 1> split_ranges;
size_t missing_begin = range.begin();
size_t missing_end = range.end();
for (auto& vmem : base::Reversed(owned_code_space)) {
Address overlap_begin = std::max(missing_begin, vmem.address());
Address overlap_end = std::min(missing_end, vmem.end());
if (overlap_begin >= overlap_end) continue;
split_ranges.emplace_back(overlap_begin, overlap_end - overlap_begin);
// Opportunistically reduce the missing range. This might terminate the loop
// early.
if (missing_begin == overlap_begin) missing_begin = overlap_end;
if (missing_end == overlap_end) missing_end = overlap_begin;
if (missing_begin >= missing_end) break;
}
#ifdef ENABLE_SLOW_DCHECKS
// The returned vector should cover the full range.
size_t total_split_size = 0;
for (auto split : split_ranges) total_split_size += split.size();
DCHECK_EQ(range.size(), total_split_size);
#endif
return split_ranges;
}
int NumWasmFunctionsInFarJumpTable(uint32_t num_declared_functions) {
return NativeModule::kNeedsFarJumpsBetweenCodeSpaces
? static_cast<int>(num_declared_functions)
: 0;
}
// Returns an overapproximation of the code size overhead per new code space
// created by the jump tables.
size_t OverheadPerCodeSpace(uint32_t num_declared_functions) {
// Overhead for the jump table.
size_t overhead = RoundUp<kCodeAlignment>(
JumpTableAssembler::SizeForNumberOfSlots(num_declared_functions));
#if defined(V8_OS_WIN64)
// On Win64, we need to reserve some pages at the beginning of an executable
// space. See {AddCodeSpace}.
overhead += Heap::GetCodeRangeReservedAreaSize();
#endif // V8_OS_WIN64
// Overhead for the far jump table.
overhead +=
RoundUp<kCodeAlignment>(JumpTableAssembler::SizeForNumberOfFarJumpSlots(
WasmCode::kRuntimeStubCount,
NumWasmFunctionsInFarJumpTable(num_declared_functions)));
return overhead;
}
size_t ReservationSize(size_t code_size_estimate, int num_declared_functions,
size_t total_reserved) {
size_t overhead = OverheadPerCodeSpace(num_declared_functions);
// Reserve a power of two at least as big as any of
// a) needed size + overhead (this is the minimum needed)
// b) 2 * overhead (to not waste too much space by overhead)
// c) 1/4 of current total reservation size (to grow exponentially)
size_t reserve_size = base::bits::RoundUpToPowerOfTwo(
std::max(std::max(RoundUp<kCodeAlignment>(code_size_estimate) + overhead,
2 * overhead),
total_reserved / 4));
// Limit by the maximum supported code space size.
return std::min(WasmCodeAllocator::kMaxCodeSpaceSize, reserve_size);
}
} // namespace
Vector<byte> WasmCodeAllocator::AllocateForCode(NativeModule* native_module,
size_t size) {
return AllocateForCodeInRegion(native_module, size, kUnrestrictedRegion,
WasmCodeAllocator::OptionalLock{});
}
Vector<byte> WasmCodeAllocator::AllocateForCodeInRegion(
NativeModule* native_module, size_t size, base::AddressRegion region,
const WasmCodeAllocator::OptionalLock& optional_lock) {
OptionalLock new_lock;
if (!optional_lock.is_locked()) new_lock.Lock(this);
const auto& locked_lock =
optional_lock.is_locked() ? optional_lock : new_lock;
DCHECK(locked_lock.is_locked());
DCHECK_EQ(code_manager_, native_module->engine()->code_manager());
DCHECK_LT(0, size);
v8::PageAllocator* page_allocator = GetPlatformPageAllocator();
size = RoundUp<kCodeAlignment>(size);
base::AddressRegion code_space =
free_code_space_.AllocateInRegion(size, region);
if (V8_UNLIKELY(code_space.is_empty())) {
// Only allocations without a specific region are allowed to fail. Otherwise
// the region must have been allocated big enough to hold all initial
// allocations (jump tables etc).
CHECK_EQ(kUnrestrictedRegion, region);
Address hint = owned_code_space_.empty() ? kNullAddress
: owned_code_space_.back().end();
size_t total_reserved = 0;
for (auto& vmem : owned_code_space_) total_reserved += vmem.size();
size_t reserve_size = ReservationSize(
size, native_module->module()->num_declared_functions, total_reserved);
VirtualMemory new_mem =
code_manager_->TryAllocate(reserve_size, reinterpret_cast<void*>(hint));
if (!new_mem.IsReserved()) {
V8::FatalProcessOutOfMemory(nullptr, "wasm code reservation");
UNREACHABLE();
}
base::AddressRegion new_region = new_mem.region();
code_manager_->AssignRange(new_region, native_module);
free_code_space_.Merge(new_region);
owned_code_space_.emplace_back(std::move(new_mem));
native_module->AddCodeSpace(new_region, locked_lock);
code_space = free_code_space_.Allocate(size);
DCHECK(!code_space.is_empty());
async_counters_->wasm_module_num_code_spaces()->AddSample(
static_cast<int>(owned_code_space_.size()));
}
const Address commit_page_size = page_allocator->CommitPageSize();
Address commit_start = RoundUp(code_space.begin(), commit_page_size);
Address commit_end = RoundUp(code_space.end(), commit_page_size);
// {commit_start} will be either code_space.start or the start of the next
// page. {commit_end} will be the start of the page after the one in which
// the allocation ends.
// We start from an aligned start, and we know we allocated vmem in
// page multiples.
// We just need to commit what's not committed. The page in which we
// start is already committed (or we start at the beginning of a page).
// The end needs to be committed all through the end of the page.
if (commit_start < commit_end) {
for (base::AddressRegion split_range : SplitRangeByReservationsIfNeeded(
{commit_start, commit_end - commit_start}, owned_code_space_)) {
code_manager_->Commit(split_range);
}
committed_code_space_.fetch_add(commit_end - commit_start);
// Committed code cannot grow bigger than maximum code space size.
DCHECK_LE(committed_code_space_.load(), FLAG_wasm_max_code_space * MB);
}
DCHECK(IsAligned(code_space.begin(), kCodeAlignment));
allocated_code_space_.Merge(code_space);
generated_code_size_.fetch_add(code_space.size(), std::memory_order_relaxed);
TRACE_HEAP("Code alloc for %p: 0x%" PRIxPTR ",+%zu\n", this,
code_space.begin(), size);
return {reinterpret_cast<byte*>(code_space.begin()), code_space.size()};
}
bool WasmCodeAllocator::SetExecutable(bool executable) {
base::MutexGuard lock(&mutex_);
if (is_executable_ == executable) return true;
TRACE_HEAP("Setting module %p as executable: %d.\n", this, executable);
v8::PageAllocator* page_allocator = GetPlatformPageAllocator();
if (FLAG_wasm_write_protect_code_memory) {
PageAllocator::Permission permission =
executable ? PageAllocator::kReadExecute : PageAllocator::kReadWrite;
#if V8_OS_WIN
// On windows, we need to switch permissions per separate virtual memory
// reservation.
// For now, in that case, we commit at reserved memory granularity.
// Technically, that may be a waste, because we may reserve more than we
// use. On 32-bit though, the scarce resource is the address space -
// committed or not.
for (auto& vmem : owned_code_space_) {
if (!SetPermissions(page_allocator, vmem.address(), vmem.size(),
permission)) {
return false;
}
TRACE_HEAP("Set %p:%p to executable:%d\n", vmem.address(), vmem.end(),
executable);
}
#else // V8_OS_WIN
size_t commit_page_size = page_allocator->CommitPageSize();
for (auto& region : allocated_code_space_.regions()) {
// allocated_code_space_ is fine-grained, so we need to
// page-align it.
size_t region_size = RoundUp(region.size(), commit_page_size);
if (!SetPermissions(page_allocator, region.begin(), region_size,
permission)) {
return false;
}
TRACE_HEAP("Set 0x%" PRIxPTR ":0x%" PRIxPTR " to executable:%d\n",
region.begin(), region.end(), executable);
}
#endif // V8_OS_WIN
}
is_executable_ = executable;
return true;
}
void WasmCodeAllocator::FreeCode(Vector<WasmCode* const> codes) {
// Zap code area and collect freed code regions.
DisjointAllocationPool freed_regions;
size_t code_size = 0;
CODE_SPACE_WRITE_SCOPE
for (WasmCode* code : codes) {
ZapCode(code->instruction_start(), code->instructions().size());
FlushInstructionCache(code->instruction_start(),
code->instructions().size());
code_size += code->instructions().size();
freed_regions.Merge(base::AddressRegion{code->instruction_start(),
code->instructions().size()});
}
freed_code_size_.fetch_add(code_size);
// Merge {freed_regions} into {freed_code_space_} and put all ranges of full
// pages to decommit into {regions_to_decommit} (decommitting is expensive,
// so try to merge regions before decommitting).
DisjointAllocationPool regions_to_decommit;
PageAllocator* allocator = GetPlatformPageAllocator();
size_t commit_page_size = allocator->CommitPageSize();
{
base::MutexGuard guard(&mutex_);
for (auto region : freed_regions.regions()) {
auto merged_region = freed_code_space_.Merge(region);
Address discard_start =
std::max(RoundUp(merged_region.begin(), commit_page_size),
RoundDown(region.begin(), commit_page_size));
Address discard_end =
std::min(RoundDown(merged_region.end(), commit_page_size),
RoundUp(region.end(), commit_page_size));
if (discard_start >= discard_end) continue;
regions_to_decommit.Merge({discard_start, discard_end - discard_start});
}
}
for (auto region : regions_to_decommit.regions()) {
size_t old_committed = committed_code_space_.fetch_sub(region.size());
DCHECK_GE(old_committed, region.size());
USE(old_committed);
for (base::AddressRegion split_range :
SplitRangeByReservationsIfNeeded(region, owned_code_space_)) {
code_manager_->Decommit(split_range);
}
}
}
size_t WasmCodeAllocator::GetNumCodeSpaces() const {
base::MutexGuard lock(&mutex_);
return owned_code_space_.size();
}
// static
constexpr base::AddressRegion WasmCodeAllocator::kUnrestrictedRegion;
NativeModule::NativeModule(WasmEngine* engine, const WasmFeatures& enabled,
VirtualMemory code_space,
std::shared_ptr<const WasmModule> module,
std::shared_ptr<Counters> async_counters,
std::shared_ptr<NativeModule>* shared_this)
: code_allocator_(engine->code_manager(), std::move(code_space),
async_counters),
enabled_features_(enabled),
module_(std::move(module)),
import_wrapper_cache_(std::unique_ptr<WasmImportWrapperCache>(
new WasmImportWrapperCache())),
engine_(engine),
use_trap_handler_(trap_handler::IsTrapHandlerEnabled() ? kUseTrapHandler
: kNoTrapHandler) {
// We receive a pointer to an empty {std::shared_ptr}, and install ourselve
// there.
DCHECK_NOT_NULL(shared_this);
DCHECK_NULL(*shared_this);
shared_this->reset(this);
compilation_state_ =
CompilationState::New(*shared_this, std::move(async_counters));
DCHECK_NOT_NULL(module_);
if (module_->num_declared_functions > 0) {
code_table_ =
std::make_unique<WasmCode*[]>(module_->num_declared_functions);
num_liftoff_function_calls_ =
std::make_unique<uint32_t[]>(module_->num_declared_functions);
// Start counter at 4 to avoid runtime calls for smaller numbers.
constexpr int kCounterStart = 4;
std::fill_n(num_liftoff_function_calls_.get(),
module_->num_declared_functions, kCounterStart);
}
code_allocator_.Init(this);
}
void NativeModule::ReserveCodeTableForTesting(uint32_t max_functions) {
WasmCodeRefScope code_ref_scope;
DCHECK_LE(module_->num_declared_functions, max_functions);
auto new_table = std::make_unique<WasmCode*[]>(max_functions);
if (module_->num_declared_functions > 0) {
memcpy(new_table.get(), code_table_.get(),
module_->num_declared_functions * sizeof(WasmCode*));
}
code_table_ = std::move(new_table);
base::AddressRegion single_code_space_region;
{
base::MutexGuard guard(&allocation_mutex_);
CHECK_EQ(1, code_space_data_.size());
single_code_space_region = code_space_data_[0].region;
}
// Re-allocate jump table.
main_jump_table_ = CreateEmptyJumpTableInRegion(
JumpTableAssembler::SizeForNumberOfSlots(max_functions),
single_code_space_region, WasmCodeAllocator::OptionalLock{});
base::MutexGuard guard(&allocation_mutex_);
code_space_data_[0].jump_table = main_jump_table_;
}
void NativeModule::LogWasmCodes(Isolate* isolate) {
if (!WasmCode::ShouldBeLogged(isolate)) return;
TRACE_EVENT1("v8.wasm", "wasm.LogWasmCodes", "functions",
module_->num_declared_functions);
// TODO(titzer): we skip the logging of the import wrappers
// here, but they should be included somehow.
int start = module_->num_imported_functions;
int end = start + module_->num_declared_functions;
WasmCodeRefScope code_ref_scope;
for (int func_index = start; func_index < end; ++func_index) {
if (WasmCode* code = GetCode(func_index)) code->LogCode(isolate);
}
}
CompilationEnv NativeModule::CreateCompilationEnv() const {
return {module(), use_trap_handler_, kRuntimeExceptionSupport,
enabled_features_, kNoLowerSimd};
}
WasmCode* NativeModule::AddCodeForTesting(Handle<Code> code) {
CODE_SPACE_WRITE_SCOPE
const size_t relocation_size = code->relocation_size();
OwnedVector<byte> reloc_info;
if (relocation_size > 0) {
reloc_info = OwnedVector<byte>::Of(
Vector<byte>{code->relocation_start(), relocation_size});
}
Handle<ByteArray> source_pos_table(code->SourcePositionTable(),
code->GetIsolate());
OwnedVector<byte> source_pos =
OwnedVector<byte>::NewForOverwrite(source_pos_table->length());
if (source_pos_table->length() > 0) {
source_pos_table->copy_out(0, source_pos.start(),
source_pos_table->length());
}
CHECK(!code->is_off_heap_trampoline());
STATIC_ASSERT(Code::kOnHeapBodyIsContiguous);
Vector<const byte> instructions(
reinterpret_cast<byte*>(code->raw_body_start()),
static_cast<size_t>(code->raw_body_size()));
const int stack_slots = code->has_safepoint_info() ? code->stack_slots() : 0;
// Metadata offsets in Code objects are relative to the start of the metadata
// section, whereas WasmCode expects offsets relative to InstructionStart.
const int base_offset = code->raw_instruction_size();
// TODO(jgruber,v8:8758): Remove this translation. It exists only because
// Code objects contains real offsets but WasmCode expects an offset of 0 to
// mean 'empty'.
const int safepoint_table_offset =
code->has_safepoint_table() ? base_offset + code->safepoint_table_offset()
: 0;
const int handler_table_offset = base_offset + code->handler_table_offset();
const int constant_pool_offset = base_offset + code->constant_pool_offset();
const int code_comments_offset = base_offset + code->code_comments_offset();
Vector<uint8_t> dst_code_bytes =
code_allocator_.AllocateForCode(this, instructions.size());
memcpy(dst_code_bytes.begin(), instructions.begin(),
instructions.size());
// Apply the relocation delta by iterating over the RelocInfo.
intptr_t delta = reinterpret_cast<Address>(dst_code_bytes.begin()) -
code->raw_instruction_start();
int mode_mask =
RelocInfo::kApplyMask | RelocInfo::ModeMask(RelocInfo::WASM_STUB_CALL);
auto jump_tables_ref =
FindJumpTablesForRegion(base::AddressRegionOf(dst_code_bytes));
Address dst_code_addr = reinterpret_cast<Address>(dst_code_bytes.begin());
Address constant_pool_start = dst_code_addr + constant_pool_offset;
RelocIterator orig_it(*code, mode_mask);
for (RelocIterator it(dst_code_bytes, reloc_info.as_vector(),
constant_pool_start, mode_mask);
!it.done(); it.next(), orig_it.next()) {
RelocInfo::Mode mode = it.rinfo()->rmode();
if (RelocInfo::IsWasmStubCall(mode)) {
uint32_t stub_call_tag = orig_it.rinfo()->wasm_call_tag();
DCHECK_LT(stub_call_tag, WasmCode::kRuntimeStubCount);
Address entry = GetNearRuntimeStubEntry(
static_cast<WasmCode::RuntimeStubId>(stub_call_tag), jump_tables_ref);
it.rinfo()->set_wasm_stub_call_address(entry, SKIP_ICACHE_FLUSH);
} else {
it.rinfo()->apply(delta);
}
}
// Flush the i-cache after relocation.
FlushInstructionCache(dst_code_bytes.begin(), dst_code_bytes.size());
std::unique_ptr<WasmCode> new_code{
new WasmCode{this, // native_module
kAnonymousFuncIndex, // index
dst_code_bytes, // instructions
stack_slots, // stack_slots
0, // tagged_parameter_slots
safepoint_table_offset, // safepoint_table_offset
handler_table_offset, // handler_table_offset
constant_pool_offset, // constant_pool_offset
code_comments_offset, // code_comments_offset
instructions.length(), // unpadded_binary_size
{}, // protected_instructions
reloc_info.as_vector(), // reloc_info
source_pos.as_vector(), // source positions
WasmCode::kFunction, // kind
ExecutionTier::kNone, // tier
kNoDebugging}}; // for_debugging
new_code->MaybePrint();
new_code->Validate();
return PublishCode(std::move(new_code));
}
void NativeModule::UseLazyStub(uint32_t func_index) {
DCHECK_LE(module_->num_imported_functions, func_index);
DCHECK_LT(func_index,
module_->num_imported_functions + module_->num_declared_functions);
if (!lazy_compile_table_) {
uint32_t num_slots = module_->num_declared_functions;
WasmCodeRefScope code_ref_scope;
CODE_SPACE_WRITE_SCOPE
base::AddressRegion single_code_space_region;
{
base::MutexGuard guard(&allocation_mutex_);
DCHECK_EQ(1, code_space_data_.size());
single_code_space_region = code_space_data_[0].region;
}
lazy_compile_table_ = CreateEmptyJumpTableInRegion(
JumpTableAssembler::SizeForNumberOfLazyFunctions(num_slots),
single_code_space_region, WasmCodeAllocator::OptionalLock{});
JumpTableAssembler::GenerateLazyCompileTable(
lazy_compile_table_->instruction_start(), num_slots,
module_->num_imported_functions,
GetNearRuntimeStubEntry(WasmCode::kWasmCompileLazy,
FindJumpTablesForRegion(base::AddressRegionOf(
lazy_compile_table_->instructions()))));
}
// Add jump table entry for jump to the lazy compile stub.
uint32_t slot_index = declared_function_index(module(), func_index);
DCHECK_NULL(code_table_[slot_index]);
Address lazy_compile_target =
lazy_compile_table_->instruction_start() +
JumpTableAssembler::LazyCompileSlotIndexToOffset(slot_index);
base::MutexGuard guard(&allocation_mutex_);
PatchJumpTablesLocked(slot_index, lazy_compile_target);
}
std::unique_ptr<WasmCode> NativeModule::AddCode(
int index, const CodeDesc& desc, int stack_slots,
int tagged_parameter_slots, Vector<const byte> protected_instructions_data,
Vector<const byte> source_position_table, WasmCode::Kind kind,
ExecutionTier tier, ForDebugging for_debugging) {
Vector<byte> code_space =
code_allocator_.AllocateForCode(this, desc.instr_size);
auto jump_table_ref =
FindJumpTablesForRegion(base::AddressRegionOf(code_space));
return AddCodeWithCodeSpace(index, desc, stack_slots, tagged_parameter_slots,
protected_instructions_data,
source_position_table, kind, tier, for_debugging,
code_space, jump_table_ref);
}
std::unique_ptr<WasmCode> NativeModule::AddCodeWithCodeSpace(
int index, const CodeDesc& desc, int stack_slots,
int tagged_parameter_slots, Vector<const byte> protected_instructions_data,
Vector<const byte> source_position_table, WasmCode::Kind kind,
ExecutionTier tier, ForDebugging for_debugging,
Vector<uint8_t> dst_code_bytes, const JumpTablesRef& jump_tables) {
Vector<byte> reloc_info{desc.buffer + desc.buffer_size - desc.reloc_size,
static_cast<size_t>(desc.reloc_size)};
UpdateCodeSize(desc.instr_size, tier, for_debugging);
// TODO(jgruber,v8:8758): Remove this translation. It exists only because
// CodeDesc contains real offsets but WasmCode expects an offset of 0 to mean
// 'empty'.
const int safepoint_table_offset =
desc.safepoint_table_size == 0 ? 0 : desc.safepoint_table_offset;
const int handler_table_offset = desc.handler_table_offset;
const int constant_pool_offset = desc.constant_pool_offset;
const int code_comments_offset = desc.code_comments_offset;
const int instr_size = desc.instr_size;
CODE_SPACE_WRITE_SCOPE
memcpy(dst_code_bytes.begin(), desc.buffer,
static_cast<size_t>(desc.instr_size));
// Apply the relocation delta by iterating over the RelocInfo.
intptr_t delta = dst_code_bytes.begin() - desc.buffer;
int mode_mask = RelocInfo::kApplyMask |
RelocInfo::ModeMask(RelocInfo::WASM_CALL) |
RelocInfo::ModeMask(RelocInfo::WASM_STUB_CALL);
Address code_start = reinterpret_cast<Address>(dst_code_bytes.begin());
Address constant_pool_start = code_start + constant_pool_offset;
for (RelocIterator it(dst_code_bytes, reloc_info, constant_pool_start,
mode_mask);
!it.done(); it.next()) {
RelocInfo::Mode mode = it.rinfo()->rmode();
if (RelocInfo::IsWasmCall(mode)) {
uint32_t call_tag = it.rinfo()->wasm_call_tag();
Address target = GetNearCallTargetForFunction(call_tag, jump_tables);
it.rinfo()->set_wasm_call_address(target, SKIP_ICACHE_FLUSH);
} else if (RelocInfo::IsWasmStubCall(mode)) {
uint32_t stub_call_tag = it.rinfo()->wasm_call_tag();
DCHECK_LT(stub_call_tag, WasmCode::kRuntimeStubCount);
Address entry = GetNearRuntimeStubEntry(
static_cast<WasmCode::RuntimeStubId>(stub_call_tag), jump_tables);
it.rinfo()->set_wasm_stub_call_address(entry, SKIP_ICACHE_FLUSH);
} else {
it.rinfo()->apply(delta);
}
}
// Flush the i-cache after relocation.
FlushInstructionCache(dst_code_bytes.begin(), dst_code_bytes.size());
// Liftoff code will not be relocated or serialized, thus do not store any
// relocation information.
if (tier == ExecutionTier::kLiftoff) reloc_info = {};
std::unique_ptr<WasmCode> code{new WasmCode{
this, index, dst_code_bytes, stack_slots, tagged_parameter_slots,
safepoint_table_offset, handler_table_offset, constant_pool_offset,
code_comments_offset, instr_size, protected_instructions_data, reloc_info,
source_position_table, kind, tier, for_debugging}};
code->MaybePrint();
code->Validate();
return code;
}
WasmCode* NativeModule::PublishCode(std::unique_ptr<WasmCode> code) {
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.wasm.detailed"),
"wasm.PublishCode");
base::MutexGuard lock(&allocation_mutex_);
return PublishCodeLocked(std::move(code));
}
std::vector<WasmCode*> NativeModule::PublishCode(
Vector<std::unique_ptr<WasmCode>> codes) {
TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("v8.wasm.detailed"),
"wasm.PublishCode", "number", codes.size());
std::vector<WasmCode*> published_code;
published_code.reserve(codes.size());
base::MutexGuard lock(&allocation_mutex_);
// The published code is put into the top-most surrounding {WasmCodeRefScope}.
for (auto& code : codes) {
published_code.push_back(PublishCodeLocked(std::move(code)));
}
return published_code;
}
WasmCode::Kind GetCodeKind(const WasmCompilationResult& result) {
switch (result.kind) {
case WasmCompilationResult::kWasmToJsWrapper:
return WasmCode::Kind::kWasmToJsWrapper;
case WasmCompilationResult::kFunction:
return WasmCode::Kind::kFunction;
default:
UNREACHABLE();
}
}
WasmCode* NativeModule::PublishCodeLocked(std::unique_ptr<WasmCode> code) {
// The caller must hold the {allocation_mutex_}, thus we fail to lock it here.
DCHECK(!allocation_mutex_.TryLock());
if (!code->IsAnonymous() &&
code->index() >= module_->num_imported_functions) {
DCHECK_LT(code->index(), num_functions());
code->RegisterTrapHandlerData();
// Assume an order of execution tiers that represents the quality of their
// generated code.
static_assert(ExecutionTier::kNone < ExecutionTier::kLiftoff &&
ExecutionTier::kLiftoff < ExecutionTier::kTurbofan,
"Assume an order on execution tiers");
uint32_t slot_idx = declared_function_index(module(), code->index());
WasmCode* prior_code = code_table_[slot_idx];
// If we are tiered down, install all debugging code (except for stepping
// code, which is only used for a single frame and never installed in the
// code table of jump table). Otherwise, install code if it was compiled
// with a higher tier.
static_assert(
kForDebugging > kNoDebugging && kWithBreakpoints > kForDebugging,
"for_debugging is ordered");
const bool update_code_table =
// Never install stepping code.
code->for_debugging() != kForStepping &&
(!prior_code ||
(tiering_state_ == kTieredDown
// Tiered down: Install breakpoints over normal debug code.
? prior_code->for_debugging() <= code->for_debugging()
// Tiered up: Install if the tier is higher than before.
: prior_code->tier() < code->tier()));
if (update_code_table) {
code_table_[slot_idx] = code.get();
if (prior_code) {
WasmCodeRefScope::AddRef(prior_code);
// The code is added to the current {WasmCodeRefScope}, hence the ref
// count cannot drop to zero here.
CHECK(!prior_code->DecRef());
}
PatchJumpTablesLocked(slot_idx, code->instruction_start());
}
if (!code->for_debugging() && tiering_state_ == kTieredDown &&
code->tier() == ExecutionTier::kTurbofan) {
liftoff_bailout_count_.fetch_add(1);
}
}
WasmCodeRefScope::AddRef(code.get());
WasmCode* result = code.get();
owned_code_.emplace(result->instruction_start(), std::move(code));
return result;
}
WasmCode* NativeModule::AddDeserializedCode(
int index, Vector<const byte> instructions, int stack_slots,
int tagged_parameter_slots, int safepoint_table_offset,
int handler_table_offset, int constant_pool_offset,
int code_comments_offset, int unpadded_binary_size,
Vector<const byte> protected_instructions_data,
Vector<const byte> reloc_info, Vector<const byte> source_position_table,
WasmCode::Kind kind, ExecutionTier tier) {
// CodeSpaceWriteScope is provided by the caller.
Vector<uint8_t> dst_code_bytes =
code_allocator_.AllocateForCode(this, instructions.size());
UpdateCodeSize(dst_code_bytes.size(), tier, kNoDebugging);
memcpy(dst_code_bytes.begin(), instructions.begin(),
instructions.size());
std::unique_ptr<WasmCode> code{new WasmCode{
this, index, dst_code_bytes, stack_slots, tagged_parameter_slots,
safepoint_table_offset, handler_table_offset, constant_pool_offset,
code_comments_offset, unpadded_binary_size, protected_instructions_data,
reloc_info, source_position_table, kind, tier, kNoDebugging}};
// Note: we do not flush the i-cache here, since the code needs to be
// relocated anyway. The caller is responsible for flushing the i-cache later.
return PublishCode(std::move(code));
}
std::vector<WasmCode*> NativeModule::SnapshotCodeTable() const {
base::MutexGuard lock(&allocation_mutex_);
WasmCode** start = code_table_.get();
WasmCode** end = start + module_->num_declared_functions;
return std::vector<WasmCode*>{start, end};
}
WasmCode* NativeModule::GetCode(uint32_t index) const {
base::MutexGuard guard(&allocation_mutex_);
WasmCode* code = code_table_[declared_function_index(module(), index)];
if (code) WasmCodeRefScope::AddRef(code);
return code;
}
bool NativeModule::HasCode(uint32_t index) const {
base::MutexGuard guard(&allocation_mutex_);
return code_table_[declared_function_index(module(), index)] != nullptr;
}
bool NativeModule::HasCodeWithTier(uint32_t index, ExecutionTier tier) const {
base::MutexGuard guard(&allocation_mutex_);
return code_table_[declared_function_index(module(), index)] != nullptr &&
code_table_[declared_function_index(module(), index)]->tier() == tier;
}
void NativeModule::SetWasmSourceMap(
std::unique_ptr<WasmModuleSourceMap> source_map) {
source_map_ = std::move(source_map);
}
WasmModuleSourceMap* NativeModule::GetWasmSourceMap() const {
return source_map_.get();
}
WasmCode* NativeModule::CreateEmptyJumpTableInRegion(
int jump_table_size, base::AddressRegion region,
const WasmCodeAllocator::OptionalLock& allocator_lock) {
// Only call this if we really need a jump table.
DCHECK_LT(0, jump_table_size);
Vector<uint8_t> code_space = code_allocator_.AllocateForCodeInRegion(
this, jump_table_size, region, allocator_lock);
DCHECK(!code_space.empty());
UpdateCodeSize(jump_table_size, ExecutionTier::kNone, kNoDebugging);
CODE_SPACE_WRITE_SCOPE
ZapCode(reinterpret_cast<Address>(code_space.begin()), code_space.size());
std::unique_ptr<WasmCode> code{
new WasmCode{this, // native_module
kAnonymousFuncIndex, // index
code_space, // instructions
0, // stack_slots
0, // tagged_parameter_slots
0, // safepoint_table_offset
jump_table_size, // handler_table_offset
jump_table_size, // constant_pool_offset
jump_table_size, // code_comments_offset
jump_table_size, // unpadded_binary_size
{}, // protected_instructions
{}, // reloc_info
{}, // source_pos
WasmCode::kJumpTable, // kind
ExecutionTier::kNone, // tier
kNoDebugging}}; // for_debugging
return PublishCode(std::move(code));
}
void NativeModule::UpdateCodeSize(size_t size, ExecutionTier tier,
ForDebugging for_debugging) {
if (for_debugging != kNoDebugging) return;
// Count jump tables (ExecutionTier::kNone) for both Liftoff and TurboFan as
// this is shared code.
if (tier != ExecutionTier::kTurbofan) liftoff_code_size_.fetch_add(size);
if (tier != ExecutionTier::kLiftoff) turbofan_code_size_.fetch_add(size);
}
void NativeModule::PatchJumpTablesLocked(uint32_t slot_index, Address target) {
// The caller must hold the {allocation_mutex_}, thus we fail to lock it here.
DCHECK(!allocation_mutex_.TryLock());
CODE_SPACE_WRITE_SCOPE
for (auto& code_space_data : code_space_data_) {
DCHECK_IMPLIES(code_space_data.jump_table, code_space_data.far_jump_table);
if (!code_space_data.jump_table) continue;
PatchJumpTableLocked(code_space_data, slot_index, target);
}
}
void NativeModule::PatchJumpTableLocked(const CodeSpaceData& code_space_data,
uint32_t slot_index, Address target) {
// The caller must hold the {allocation_mutex_}, thus we fail to lock it here.
DCHECK(!allocation_mutex_.TryLock());
DCHECK_NOT_NULL(code_space_data.jump_table);
DCHECK_NOT_NULL(code_space_data.far_jump_table);
DCHECK_LT(slot_index, module_->num_declared_functions);
Address jump_table_slot =
code_space_data.jump_table->instruction_start() +
JumpTableAssembler::JumpSlotIndexToOffset(slot_index);
uint32_t far_jump_table_offset = JumpTableAssembler::FarJumpSlotIndexToOffset(
WasmCode::kRuntimeStubCount + slot_index);
// Only pass the far jump table start if the far jump table actually has a
// slot for this function index (i.e. does not only contain runtime stubs).
bool has_far_jump_slot =
far_jump_table_offset <
code_space_data.far_jump_table->instructions().size();
Address far_jump_table_start =
code_space_data.far_jump_table->instruction_start();
Address far_jump_table_slot =
has_far_jump_slot ? far_jump_table_start + far_jump_table_offset
: kNullAddress;
JumpTableAssembler::PatchJumpTableSlot(jump_table_slot, far_jump_table_slot,
target);
}
void NativeModule::AddCodeSpace(
base::AddressRegion region,
const WasmCodeAllocator::OptionalLock& allocator_lock) {
// Each code space must be at least twice as large as the overhead per code
// space. Otherwise, we are wasting too much memory.
DCHECK_GE(region.size(),
2 * OverheadPerCodeSpace(module()->num_declared_functions));
#if defined(V8_OS_WIN64)
// On some platforms, specifically Win64, we need to reserve some pages at
// the beginning of an executable space.
// See src/heap/spaces.cc, MemoryAllocator::InitializeCodePageAllocator() and
// https://cs.chromium.org/chromium/src/components/crash/content/app/crashpad_win.cc?rcl=fd680447881449fba2edcf0589320e7253719212&l=204
// for details.
if (engine_->code_manager()
->CanRegisterUnwindInfoForNonABICompliantCodeRange()) {
size_t size = Heap::GetCodeRangeReservedAreaSize();
DCHECK_LT(0, size);
Vector<byte> padding = code_allocator_.AllocateForCodeInRegion(
this, size, region, allocator_lock);
CHECK_EQ(reinterpret_cast<Address>(padding.begin()), region.begin());
win64_unwindinfo::RegisterNonABICompliantCodeRange(
reinterpret_cast<void*>(region.begin()), region.size());
}
#endif // V8_OS_WIN64
WasmCodeRefScope code_ref_scope;
CODE_SPACE_WRITE_SCOPE
WasmCode* jump_table = nullptr;
WasmCode* far_jump_table = nullptr;
const uint32_t num_wasm_functions = module_->num_declared_functions;
const bool is_first_code_space = code_space_data_.empty();
// We always need a far jump table, because it contains the runtime stubs.
const bool needs_far_jump_table = !FindJumpTablesForRegion(region).is_valid();
const bool needs_jump_table = num_wasm_functions > 0 && needs_far_jump_table;
if (needs_jump_table) {
jump_table = CreateEmptyJumpTableInRegion(
JumpTableAssembler::SizeForNumberOfSlots(num_wasm_functions), region,
allocator_lock);
CHECK(region.contains(jump_table->instruction_start()));
}
if (needs_far_jump_table) {
int num_function_slots = NumWasmFunctionsInFarJumpTable(num_wasm_functions);
far_jump_table = CreateEmptyJumpTableInRegion(
JumpTableAssembler::SizeForNumberOfFarJumpSlots(
WasmCode::kRuntimeStubCount,
NumWasmFunctionsInFarJumpTable(num_function_slots)),
region, allocator_lock);
CHECK(region.contains(far_jump_table->instruction_start()));
EmbeddedData embedded_data = EmbeddedData::FromBlob();
#define RUNTIME_STUB(Name) Builtins::k##Name,
#define RUNTIME_STUB_TRAP(Name) RUNTIME_STUB(ThrowWasm##Name)
Builtins::Name stub_names[WasmCode::kRuntimeStubCount] = {
WASM_RUNTIME_STUB_LIST(RUNTIME_STUB, RUNTIME_STUB_TRAP)};
#undef RUNTIME_STUB
#undef RUNTIME_STUB_TRAP
STATIC_ASSERT(Builtins::kAllBuiltinsAreIsolateIndependent);
Address builtin_addresses[WasmCode::kRuntimeStubCount];
for (int i = 0; i < WasmCode::kRuntimeStubCount; ++i) {
Builtins::Name builtin = stub_names[i];
builtin_addresses[i] = embedded_data.InstructionStartOfBuiltin(builtin);
}
JumpTableAssembler::GenerateFarJumpTable(
far_jump_table->instruction_start(), builtin_addresses,
WasmCode::kRuntimeStubCount, num_function_slots);
}
if (is_first_code_space) {
// This can be updated and accessed without locks, since the addition of the
// first code space happens during initialization of the {NativeModule},
// where no concurrent accesses are possible.
main_jump_table_ = jump_table;
main_far_jump_table_ = far_jump_table;
}
base::MutexGuard guard(&allocation_mutex_);
code_space_data_.push_back(CodeSpaceData{region, jump_table, far_jump_table});
if (jump_table && !is_first_code_space) {
// Patch the new jump table(s) with existing functions. If this is the first
// code space, there cannot be any functions that have been compiled yet.
const CodeSpaceData& new_code_space_data = code_space_data_.back();
for (uint32_t slot_index = 0; slot_index < num_wasm_functions;
++slot_index) {
if (code_table_[slot_index]) {
PatchJumpTableLocked(new_code_space_data, slot_index,
code_table_[slot_index]->instruction_start());
} else if (lazy_compile_table_) {
Address lazy_compile_target =
lazy_compile_table_->instruction_start() +
JumpTableAssembler::LazyCompileSlotIndexToOffset(slot_index);
PatchJumpTableLocked(new_code_space_data, slot_index,
lazy_compile_target);
}
}
}
}
namespace {
class NativeModuleWireBytesStorage final : public WireBytesStorage {
public:
explicit NativeModuleWireBytesStorage(
std::shared_ptr<OwnedVector<const uint8_t>> wire_bytes)
: wire_bytes_(std::move(wire_bytes)) {}
Vector<const uint8_t> GetCode(WireBytesRef ref) const final {
return std::atomic_load(&wire_bytes_)
->as_vector()
.SubVector(ref.offset(), ref.end_offset());
}
private:
const std::shared_ptr<OwnedVector<const uint8_t>> wire_bytes_;
};
} // namespace
void NativeModule::SetWireBytes(OwnedVector<const uint8_t> wire_bytes) {
auto shared_wire_bytes =
std::make_shared<OwnedVector<const uint8_t>>(std::move(wire_bytes));
std::atomic_store(&wire_bytes_, shared_wire_bytes);
if (!shared_wire_bytes->empty()) {
compilation_state_->SetWireBytesStorage(
std::make_shared<NativeModuleWireBytesStorage>(
std::move(shared_wire_bytes)));
}
}
WasmCode* NativeModule::Lookup(Address pc) const {
base::MutexGuard lock(&allocation_mutex_);
auto iter = owned_code_.upper_bound(pc);
if (iter == owned_code_.begin()) return nullptr;
--iter;
WasmCode* candidate = iter->second.get();
DCHECK_EQ(candidate->instruction_start(), iter->first);
if (!candidate->contains(pc)) return nullptr;
WasmCodeRefScope::AddRef(candidate);
return candidate;
}
uint32_t NativeModule::GetJumpTableOffset(uint32_t func_index) const {
uint32_t slot_idx = declared_function_index(module(), func_index);
return JumpTableAssembler::JumpSlotIndexToOffset(slot_idx);
}
Address NativeModule::GetCallTargetForFunction(uint32_t func_index) const {
// Return the jump table slot for that function index.
DCHECK_NOT_NULL(main_jump_table_);
uint32_t slot_offset = GetJumpTableOffset(func_index);
DCHECK_LT(slot_offset, main_jump_table_->instructions().size());
return main_jump_table_->instruction_start() + slot_offset;
}
NativeModule::JumpTablesRef NativeModule::FindJumpTablesForRegion(
base::AddressRegion code_region) const {
auto jump_table_usable = [code_region](const WasmCode* jump_table) {
Address table_start = jump_table->instruction_start();
Address table_end = table_start + jump_table->instructions().size();
// Compute the maximum distance from anywhere in the code region to anywhere
// in the jump table, avoiding any underflow.
size_t max_distance = std::max(
code_region.end() > table_start ? code_region.end() - table_start : 0,
table_end > code_region.begin() ? table_end - code_region.begin() : 0);
// We can allow a max_distance that is equal to kMaxCodeSpaceSize, because
// every call or jump will target an address *within* the region, but never
// exactly the end of the region. So all occuring offsets are actually
// smaller than max_distance.
return max_distance <= WasmCodeAllocator::kMaxCodeSpaceSize;
};
// Fast path: Try to use {main_jump_table_} and {main_far_jump_table_}.
// Access to these fields is possible without locking, since these fields are
// initialized on construction of the {NativeModule}.
if (main_far_jump_table_ && jump_table_usable(main_far_jump_table_) &&
(main_jump_table_ == nullptr || jump_table_usable(main_jump_table_))) {
return {
main_jump_table_ ? main_jump_table_->instruction_start() : kNullAddress,
main_far_jump_table_->instruction_start()};
}
// Otherwise, take the mutex and look for another suitable jump table.
base::MutexGuard guard(&allocation_mutex_);
for (auto& code_space_data : code_space_data_) {
DCHECK_IMPLIES(code_space_data.jump_table, code_space_data.far_jump_table);
if (!code_space_data.far_jump_table) continue;
// Only return these jump tables if they are reachable from the whole
// {code_region}.
if (kNeedsFarJumpsBetweenCodeSpaces &&
(!jump_table_usable(code_space_data.far_jump_table) ||
(code_space_data.jump_table &&
!jump_table_usable(code_space_data.jump_table)))) {
continue;
}
return {code_space_data.jump_table
? code_space_data.jump_table->instruction_start()
: kNullAddress,
code_space_data.far_jump_table->instruction_start()};
}
return {};
}
Address NativeModule::GetNearCallTargetForFunction(
uint32_t func_index, const JumpTablesRef& jump_tables) const {
DCHECK(jump_tables.is_valid());
uint32_t slot_offset = GetJumpTableOffset(func_index);
return jump_tables.jump_table_start + slot_offset;
}
Address NativeModule::GetNearRuntimeStubEntry(
WasmCode::RuntimeStubId index, const JumpTablesRef& jump_tables) const {
DCHECK(jump_tables.is_valid());
auto offset = JumpTableAssembler::FarJumpSlotIndexToOffset(index);
return jump_tables.far_jump_table_start + offset;
}
uint32_t NativeModule::GetFunctionIndexFromJumpTableSlot(
Address slot_address) const {
WasmCodeRefScope code_refs;
WasmCode* code = Lookup(slot_address);
DCHECK_NOT_NULL(code);
DCHECK_EQ(WasmCode::kJumpTable, code->kind());
uint32_t slot_offset =
static_cast<uint32_t>(slot_address - code->instruction_start());
uint32_t slot_idx = JumpTableAssembler::SlotOffsetToIndex(slot_offset);
DCHECK_LT(slot_idx, module_->num_declared_functions);
DCHECK_EQ(slot_address,
code->instruction_start() +
JumpTableAssembler::JumpSlotIndexToOffset(slot_idx));
return module_->num_imported_functions + slot_idx;
}
WasmCode::RuntimeStubId NativeModule::GetRuntimeStubId(Address target) const {
base::MutexGuard guard(&allocation_mutex_);
for (auto& code_space_data : code_space_data_) {
if (code_space_data.far_jump_table != nullptr &&
code_space_data.far_jump_table->contains(target)) {
uint32_t offset = static_cast<uint32_t>(
target - code_space_data.far_jump_table->instruction_start());
uint32_t index = JumpTableAssembler::FarJumpSlotOffsetToIndex(offset);
if (index >= WasmCode::kRuntimeStubCount) continue;
if (JumpTableAssembler::FarJumpSlotIndexToOffset(index) != offset) {
continue;
}
return static_cast<WasmCode::RuntimeStubId>(index);
}
}
// Invalid address.
return WasmCode::kRuntimeStubCount;
}
NativeModule::~NativeModule() {
TRACE_HEAP("Deleting native module: %p\n", this);
// Cancel all background compilation before resetting any field of the
// NativeModule or freeing anything.
compilation_state_->CancelCompilation();
engine_->FreeNativeModule(this);
// Free the import wrapper cache before releasing the {WasmCode} objects in
// {owned_code_}. The destructor of {WasmImportWrapperCache} still needs to
// decrease reference counts on the {WasmCode} objects.
import_wrapper_cache_.reset();
}
WasmCodeManager::WasmCodeManager(size_t max_committed)
: max_committed_code_space_(max_committed),
critical_committed_code_space_(max_committed / 2) {
DCHECK_LE(max_committed, FLAG_wasm_max_code_space * MB);
}
#if defined(V8_OS_WIN64)
bool WasmCodeManager::CanRegisterUnwindInfoForNonABICompliantCodeRange() const {
return win64_unwindinfo::CanRegisterUnwindInfoForNonABICompliantCodeRange() &&
FLAG_win64_unwinding_info;
}
#endif // V8_OS_WIN64
void WasmCodeManager::Commit(base::AddressRegion region) {
// TODO(v8:8462): Remove eager commit once perf supports remapping.
if (V8_UNLIKELY(FLAG_perf_prof)) return;
DCHECK(IsAligned(region.begin(), CommitPageSize()));
DCHECK(IsAligned(region.size(), CommitPageSize()));
// Reserve the size. Use CAS loop to avoid overflow on
// {total_committed_code_space_}.
size_t old_value = total_committed_code_space_.load();
while (true) {
DCHECK_GE(max_committed_code_space_, old_value);
if (region.size() > max_committed_code_space_ - old_value) {
V8::FatalProcessOutOfMemory(
nullptr,
"WasmCodeManager::Commit: Exceeding maximum wasm code space");
UNREACHABLE();
}
if (total_committed_code_space_.compare_exchange_weak(
old_value, old_value + region.size())) {
break;
}
}
PageAllocator::Permission permission = FLAG_wasm_write_protect_code_memory
? PageAllocator::kReadWrite
: PageAllocator::kReadWriteExecute;
TRACE_HEAP("Setting rw permissions for 0x%" PRIxPTR ":0x%" PRIxPTR "\n",
region.begin(), region.end());
if (!SetPermissions(GetPlatformPageAllocator(), region.begin(), region.size(),
permission)) {
// Highly unlikely.
V8::FatalProcessOutOfMemory(
nullptr,
"WasmCodeManager::Commit: Cannot make pre-reserved region writable");
UNREACHABLE();
}
}
void WasmCodeManager::Decommit(base::AddressRegion region) {
// TODO(v8:8462): Remove this once perf supports remapping.
if (V8_UNLIKELY(FLAG_perf_prof)) return;
PageAllocator* allocator = GetPlatformPageAllocator();
DCHECK(IsAligned(region.begin(), allocator->CommitPageSize()));
DCHECK(IsAligned(region.size(), allocator->CommitPageSize()));
size_t old_committed = total_committed_code_space_.fetch_sub(region.size());
DCHECK_LE(region.size(), old_committed);
USE(old_committed);
TRACE_HEAP("Discarding system pages 0x%" PRIxPTR ":0x%" PRIxPTR "\n",
region.begin(), region.end());
CHECK(allocator->SetPermissions(reinterpret_cast<void*>(region.begin()),
region.size(), PageAllocator::kNoAccess));
}
void WasmCodeManager::AssignRange(base::AddressRegion region,
NativeModule* native_module) {
base::MutexGuard lock(&native_modules_mutex_);
lookup_map_.insert(std::make_pair(
region.begin(), std::make_pair(region.end(), native_module)));
}
VirtualMemory WasmCodeManager::TryAllocate(size_t size, void* hint) {
v8::PageAllocator* page_allocator = GetPlatformPageAllocator();
DCHECK_GT(size, 0);
size_t allocate_page_size = page_allocator->AllocatePageSize();
size = RoundUp(size, allocate_page_size);
if (!BackingStore::ReserveAddressSpace(size)) return {};
if (hint == nullptr) hint = page_allocator->GetRandomMmapAddr();
// When we start exposing Wasm in jitless mode, then the jitless flag
// will have to determine whether we set kMapAsJittable or not.
DCHECK(!FLAG_jitless);
VirtualMemory mem(page_allocator, size, hint, allocate_page_size,
VirtualMemory::kMapAsJittable);
if (!mem.IsReserved()) {
BackingStore::ReleaseReservation(size);
return {};
}
TRACE_HEAP("VMem alloc: 0x%" PRIxPTR ":0x%" PRIxPTR " (%zu)\n", mem.address(),
mem.end(), mem.size());
// TODO(v8:8462): Remove eager commit once perf supports remapping.
if (FLAG_perf_prof) {
SetPermissions(GetPlatformPageAllocator(), mem.address(), mem.size(),
PageAllocator::kReadWriteExecute);
}
return mem;
}
namespace {
// The numbers here are rough estimates, used to calculate the size of the
// initial code reservation and for estimating the amount of external memory
// reported to the GC.
// They do not need to be accurate. Choosing them too small will result in
// separate code spaces being allocated (compile time and runtime overhead),
// choosing them too large results in over-reservation (virtual address space
// only).
// The current numbers have been determined on 2019-11-11 by clemensb@, based
// on one small and one large module compiled from C++ by Emscripten. If in
// doubt, they where chosen slightly larger than required, as over-reservation
// is not a big issue currently.
// Numbers will change when Liftoff or TurboFan evolve, other toolchains are
// used to produce the wasm code, or characteristics of wasm modules on the
// web change. They might require occasional tuning.
// This patch might help to find reasonable numbers for any future adaptation:
// https://crrev.com/c/1910945
#if V8_TARGET_ARCH_X64
constexpr size_t kTurbofanFunctionOverhead = 20;
constexpr size_t kTurbofanCodeSizeMultiplier = 3;
constexpr size_t kLiftoffFunctionOverhead = 60;
constexpr size_t kLiftoffCodeSizeMultiplier = 4;
constexpr size_t kImportSize = 350;
#elif V8_TARGET_ARCH_IA32
constexpr size_t kTurbofanFunctionOverhead = 20;
constexpr size_t kTurbofanCodeSizeMultiplier = 4;
constexpr size_t kLiftoffFunctionOverhead = 60;
constexpr size_t kLiftoffCodeSizeMultiplier = 5;
constexpr size_t kImportSize = 480;
#elif V8_TARGET_ARCH_ARM
constexpr size_t kTurbofanFunctionOverhead = 40;
constexpr size_t kTurbofanCodeSizeMultiplier = 4;
constexpr size_t kLiftoffFunctionOverhead = 108;
constexpr size_t kLiftoffCodeSizeMultiplier = 7;
constexpr size_t kImportSize = 750;
#elif V8_TARGET_ARCH_ARM64
constexpr size_t kTurbofanFunctionOverhead = 60;
constexpr size_t kTurbofanCodeSizeMultiplier = 4;
constexpr size_t kLiftoffFunctionOverhead = 80;
constexpr size_t kLiftoffCodeSizeMultiplier = 7;
constexpr size_t kImportSize = 750;
#else
// Other platforms should add their own estimates if needed. Numbers below are
// the minimum of other architectures.
constexpr size_t kTurbofanFunctionOverhead = 20;
constexpr size_t kTurbofanCodeSizeMultiplier = 3;
constexpr size_t kLiftoffFunctionOverhead = 60;
constexpr size_t kLiftoffCodeSizeMultiplier = 4;
constexpr size_t kImportSize = 350;
#endif
} // namespace
// static
size_t WasmCodeManager::EstimateLiftoffCodeSize(int body_size) {
return kLiftoffFunctionOverhead + kCodeAlignment / 2 +
body_size * kLiftoffCodeSizeMultiplier;
}
// static
size_t WasmCodeManager::EstimateNativeModuleCodeSize(const WasmModule* module,
bool include_liftoff) {
int num_functions = static_cast<int>(module->num_declared_functions);
int num_imported_functions = static_cast<int>(module->num_imported_functions);
int code_section_length = 0;
if (num_functions > 0) {
DCHECK_EQ(module->functions.size(), num_imported_functions + num_functions);
auto* first_fn = &module->functions[module->num_imported_functions];
auto* last_fn = &module->functions.back();
code_section_length =
static_cast<int>(last_fn->code.end_offset() - first_fn->code.offset());
}
return EstimateNativeModuleCodeSize(num_functions, num_imported_functions,
code_section_length, include_liftoff);
}
// static
size_t WasmCodeManager::EstimateNativeModuleCodeSize(int num_functions,
int num_imported_functions,
int code_section_length,
bool include_liftoff) {
const size_t overhead_per_function =
kTurbofanFunctionOverhead + kCodeAlignment / 2 +
(include_liftoff ? kLiftoffFunctionOverhead + kCodeAlignment / 2 : 0);
const size_t overhead_per_code_byte =
kTurbofanCodeSizeMultiplier +
(include_liftoff ? kLiftoffCodeSizeMultiplier : 0);
const size_t jump_table_size = RoundUp<kCodeAlignment>(
JumpTableAssembler::SizeForNumberOfSlots(num_functions));
const size_t far_jump_table_size =
RoundUp<kCodeAlignment>(JumpTableAssembler::SizeForNumberOfFarJumpSlots(
WasmCode::kRuntimeStubCount,
NumWasmFunctionsInFarJumpTable(num_functions)));
return jump_table_size // jump table
+ far_jump_table_size // far jump table
+ overhead_per_function * num_functions // per function
+ overhead_per_code_byte * code_section_length // per code byte
+ kImportSize * num_imported_functions; // per import
}
// static
size_t WasmCodeManager::EstimateNativeModuleMetaDataSize(
const WasmModule* module) {
size_t wasm_module_estimate = EstimateStoredSize(module);
uint32_t num_wasm_functions = module->num_declared_functions;
// TODO(wasm): Include wire bytes size.
size_t native_module_estimate =
sizeof(NativeModule) + /* NativeModule struct */
(sizeof(WasmCode*) * num_wasm_functions) + /* code table size */
(sizeof(WasmCode) * num_wasm_functions); /* code object size */
return wasm_module_estimate + native_module_estimate;
}
std::shared_ptr<NativeModule> WasmCodeManager::NewNativeModule(
WasmEngine* engine, Isolate* isolate, const WasmFeatures& enabled,
size_t code_size_estimate, std::shared_ptr<const WasmModule> module) {
DCHECK_EQ(this, isolate->wasm_engine()->code_manager());
if (total_committed_code_space_.load() >
critical_committed_code_space_.load()) {
(reinterpret_cast<v8::Isolate*>(isolate))
->MemoryPressureNotification(MemoryPressureLevel::kCritical);
size_t committed = total_committed_code_space_.load();
DCHECK_GE(max_committed_code_space_, committed);
critical_committed_code_space_.store(
committed + (max_committed_code_space_ - committed) / 2);
}
// If we cannot add code space later, reserve enough address space up front.
size_t code_vmem_size =
ReservationSize(code_size_estimate, module->num_declared_functions, 0);
// The '--wasm-max-code-space-reservation' testing flag can be used to reduce
// the maximum size of the initial code space reservation (in MB).
if (FLAG_wasm_max_initial_code_space_reservation > 0) {
size_t flag_max_bytes =
static_cast<size_t>(FLAG_wasm_max_initial_code_space_reservation) * MB;
if (flag_max_bytes < code_vmem_size) code_vmem_size = flag_max_bytes;
}
// Try up to two times; getting rid of dead JSArrayBuffer allocations might
// require two GCs because the first GC maybe incremental and may have
// floating garbage.
static constexpr int kAllocationRetries = 2;
VirtualMemory code_space;
for (int retries = 0;; ++retries) {
code_space = TryAllocate(code_vmem_size);
if (code_space.IsReserved()) break;
if (retries == kAllocationRetries) {
V8::FatalProcessOutOfMemory(isolate, "NewNativeModule");
UNREACHABLE();
}
// Run one GC, then try the allocation again.
isolate->heap()->MemoryPressureNotification(MemoryPressureLevel::kCritical,
true);
}
Address start = code_space.address();
size_t size = code_space.size();
Address end = code_space.end();
std::shared_ptr<NativeModule> ret;
new NativeModule(engine, enabled, std::move(code_space), std::move(module),
isolate->async_counters(), &ret);
// The constructor initialized the shared_ptr.
DCHECK_NOT_NULL(ret);
TRACE_HEAP("New NativeModule %p: Mem: %" PRIuPTR ",+%zu\n", ret.get(), start,
size);
base::MutexGuard lock(&native_modules_mutex_);
lookup_map_.insert(std::make_pair(start, std::make_pair(end, ret.get())));
return ret;
}
void NativeModule::SampleCodeSize(
Counters* counters, NativeModule::CodeSamplingTime sampling_time) const {
size_t code_size = sampling_time == kSampling
? code_allocator_.committed_code_space()
: code_allocator_.generated_code_size();
int code_size_mb = static_cast<int>(code_size / MB);
Histogram* histogram = nullptr;
switch (sampling_time) {
case kAfterBaseline:
histogram = counters->wasm_module_code_size_mb_after_baseline();
break;
case kAfterTopTier:
histogram = counters->wasm_module_code_size_mb_after_top_tier();
break;
case kSampling: {
histogram = counters->wasm_module_code_size_mb();
// If this is a wasm module of >= 2MB, also sample the freed code size,
// absolute and relative. Code GC does not happen on asm.js modules, and
// small modules will never trigger GC anyway.
size_t generated_size = code_allocator_.generated_code_size();
if (generated_size >= 2 * MB && module()->origin == kWasmOrigin) {
size_t freed_size = code_allocator_.freed_code_size();
DCHECK_LE(freed_size, generated_size);
int freed_percent = static_cast<int>(100 * freed_size / generated_size);
counters->wasm_module_freed_code_size_percent()->AddSample(
freed_percent);
}
break;
}
}
histogram->AddSample(code_size_mb);
}
std::unique_ptr<WasmCode> NativeModule::AddCompiledCode(
WasmCompilationResult result) {
std::vector<std::unique_ptr<WasmCode>> code = AddCompiledCode({&result, 1});
return std::move(code[0]);
}
std::vector<std::unique_ptr<WasmCode>> NativeModule::AddCompiledCode(
Vector<WasmCompilationResult> results) {
TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("v8.wasm.detailed"),
"wasm.AddCompiledCode", "num", results.size());
DCHECK(!results.empty());
// First, allocate code space for all the results.
size_t total_code_space = 0;
for (auto& result : results) {
DCHECK(result.succeeded());
total_code_space += RoundUp<kCodeAlignment>(result.code_desc.instr_size);
}
Vector<byte> code_space =
code_allocator_.AllocateForCode(this, total_code_space);
// Lookup the jump tables to use once, then use for all code objects.
auto jump_tables = FindJumpTablesForRegion(base::AddressRegionOf(code_space));
std::vector<std::unique_ptr<WasmCode>> generated_code;
generated_code.reserve(results.size());
// Now copy the generated code into the code space and relocate it.
CODE_SPACE_WRITE_SCOPE
for (auto& result : results) {
DCHECK_EQ(result.code_desc.buffer, result.instr_buffer.get());
size_t code_size = RoundUp<kCodeAlignment>(result.code_desc.instr_size);
Vector<byte> this_code_space = code_space.SubVector(0, code_size);
code_space += code_size;
generated_code.emplace_back(AddCodeWithCodeSpace(
result.func_index, result.code_desc, result.frame_slot_count,
result.tagged_parameter_slots,
result.protected_instructions_data.as_vector(),
result.source_positions.as_vector(), GetCodeKind(result),
result.result_tier, result.for_debugging, this_code_space,
jump_tables));
}
DCHECK_EQ(0, code_space.size());
return generated_code;
}
void NativeModule::SetTieringState(TieringState new_tiering_state) {
// Do not tier down asm.js (just never change the tiering state).
if (module()->origin != kWasmOrigin) return;
base::MutexGuard lock(&allocation_mutex_);
tiering_state_ = new_tiering_state;
}
bool NativeModule::IsTieredDown() {
base::MutexGuard lock(&allocation_mutex_);
return tiering_state_ == kTieredDown;
}
void NativeModule::RecompileForTiering() {
// Read the tiering state under the lock, then trigger recompilation after
// releasing the lock. If the tiering state was changed when the triggered
// compilation units finish, code installation will handle that correctly.
TieringState current_state;
{
base::MutexGuard lock(&allocation_mutex_);
current_state = tiering_state_;
}
RecompileNativeModule(this, current_state);
}
std::vector<int> NativeModule::FindFunctionsToRecompile(
TieringState new_tiering_state) {
base::MutexGuard guard(&allocation_mutex_);
std::vector<int> function_indexes;
int imported = module()->num_imported_functions;
int declared = module()->num_declared_functions;
for (int slot_index = 0; slot_index < declared; ++slot_index) {
int function_index = imported + slot_index;
WasmCode* code = code_table_[slot_index];
bool code_is_good = new_tiering_state == kTieredDown
? code && code->for_debugging()
: code && code->tier() == ExecutionTier::kTurbofan;
if (!code_is_good) function_indexes.push_back(function_index);
}
return function_indexes;
}
void NativeModule::FreeCode(Vector<WasmCode* const> codes) {
// Free the code space.
code_allocator_.FreeCode(codes);
DebugInfo* debug_info = nullptr;
{
base::MutexGuard guard(&allocation_mutex_);
debug_info = debug_info_.get();
// Free the {WasmCode} objects. This will also unregister trap handler data.
for (WasmCode* code : codes) {
DCHECK_EQ(1, owned_code_.count(code->instruction_start()));
owned_code_.erase(code->instruction_start());
}
}
// Remove debug side tables for all removed code objects, after releasing our
// lock. This is to avoid lock order inversion.
if (debug_info) debug_info->RemoveDebugSideTables(codes);
}
size_t NativeModule::GetNumberOfCodeSpacesForTesting() const {
return code_allocator_.GetNumCodeSpaces();
}
bool NativeModule::HasDebugInfo() const {
base::MutexGuard guard(&allocation_mutex_);
return debug_info_ != nullptr;
}
DebugInfo* NativeModule::GetDebugInfo() {
base::MutexGuard guard(&allocation_mutex_);
if (!debug_info_) debug_info_ = std::make_unique<DebugInfo>(this);
return debug_info_.get();
}
void WasmCodeManager::FreeNativeModule(Vector<VirtualMemory> owned_code_space,
size_t committed_size) {
base::MutexGuard lock(&native_modules_mutex_);
for (auto& code_space : owned_code_space) {
DCHECK(code_space.IsReserved());
TRACE_HEAP("VMem Release: 0x%" PRIxPTR ":0x%" PRIxPTR " (%zu)\n",
code_space.address(), code_space.end(), code_space.size());
#if defined(V8_OS_WIN64)
if (CanRegisterUnwindInfoForNonABICompliantCodeRange()) {
win64_unwindinfo::UnregisterNonABICompliantCodeRange(
reinterpret_cast<void*>(code_space.address()));
}
#endif // V8_OS_WIN64
lookup_map_.erase(code_space.address());
BackingStore::ReleaseReservation(code_space.size());
code_space.Free();
DCHECK(!code_space.IsReserved());
}
DCHECK(IsAligned(committed_size, CommitPageSize()));
// TODO(v8:8462): Remove this once perf supports remapping.
if (!FLAG_perf_prof) {
size_t old_committed =
total_committed_code_space_.fetch_sub(committed_size);
DCHECK_LE(committed_size, old_committed);
USE(old_committed);
}
}
NativeModule* WasmCodeManager::LookupNativeModule(Address pc) const {
base::MutexGuard lock(&native_modules_mutex_);
if (lookup_map_.empty()) return nullptr;
auto iter = lookup_map_.upper_bound(pc);
if (iter == lookup_map_.begin()) return nullptr;
--iter;
Address region_start = iter->first;
Address region_end = iter->second.first;
NativeModule* candidate = iter->second.second;
DCHECK_NOT_NULL(candidate);
return region_start <= pc && pc < region_end ? candidate : nullptr;
}
WasmCode* WasmCodeManager::LookupCode(Address pc) const {
NativeModule* candidate = LookupNativeModule(pc);
return candidate ? candidate->Lookup(pc) : nullptr;
}
// TODO(v8:7424): Code protection scopes are not yet supported with shared code
// enabled and need to be revisited.
NativeModuleModificationScope::NativeModuleModificationScope(
NativeModule* native_module)
: native_module_(native_module) {
if (FLAG_wasm_write_protect_code_memory && native_module_ &&
(native_module_->modification_scope_depth_++) == 0) {
bool success = native_module_->SetExecutable(false);
CHECK(success);
}
}
NativeModuleModificationScope::~NativeModuleModificationScope() {
if (FLAG_wasm_write_protect_code_memory && native_module_ &&
(native_module_->modification_scope_depth_--) == 1) {
bool success = native_module_->SetExecutable(true);
CHECK(success);
}
}
// Disabling these code currently to fix API leaks, wasm module will be removed
// as a whole later.
#if !defined(V8_OS_STARBOARD)
namespace {
thread_local WasmCodeRefScope* current_code_refs_scope = nullptr;
} // namespace
#endif
WasmCodeRefScope::WasmCodeRefScope()
#if !defined(V8_OS_STARBOARD)
: previous_scope_(current_code_refs_scope) {
current_code_refs_scope = this;
}
#else
: previous_scope_(nullptr) {}
#endif
WasmCodeRefScope::~WasmCodeRefScope() {
#if !defined(V8_OS_STARBOARD)
DCHECK_EQ(this, current_code_refs_scope);
current_code_refs_scope = previous_scope_;
std::vector<WasmCode*> code_ptrs;
code_ptrs.reserve(code_ptrs_.size());
code_ptrs.assign(code_ptrs_.begin(), code_ptrs_.end());
WasmCode::DecrementRefCount(VectorOf(code_ptrs));
#endif
}
// static
void WasmCodeRefScope::AddRef(WasmCode* code) {
#if !defined(V8_OS_STARBOARD)
DCHECK_NOT_NULL(code);
WasmCodeRefScope* current_scope = current_code_refs_scope;
DCHECK_NOT_NULL(current_scope);
auto entry = current_scope->code_ptrs_.insert(code);
// If we added a new entry, increment the ref counter.
if (entry.second) code->IncRef();
#endif
}
const char* GetRuntimeStubName(WasmCode::RuntimeStubId stub_id) {
#define RUNTIME_STUB_NAME(Name) #Name,
#define RUNTIME_STUB_NAME_TRAP(Name) "ThrowWasm" #Name,
constexpr const char* runtime_stub_names[] = {WASM_RUNTIME_STUB_LIST(
RUNTIME_STUB_NAME, RUNTIME_STUB_NAME_TRAP) "<unknown>"};
#undef RUNTIME_STUB_NAME
#undef RUNTIME_STUB_NAME_TRAP
STATIC_ASSERT(arraysize(runtime_stub_names) ==
WasmCode::kRuntimeStubCount + 1);
DCHECK_GT(arraysize(runtime_stub_names), stub_id);
return runtime_stub_names[stub_id];
}
} // namespace wasm
} // namespace internal
} // namespace v8
#undef TRACE_HEAP