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// Copyright (c) 1994-2006 Sun Microsystems Inc.
// 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.
//
// - Redistribution 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 Sun Microsystems or the names of 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.
// The original source code covered by the above license above has been
// modified significantly by Google Inc.
// Copyright 2012 the V8 project authors. All rights reserved.
#include "src/codegen/assembler.h"
#ifdef V8_CODE_COMMENTS
#include <iomanip>
#endif
#include "src/base/vector.h"
#include "src/codegen/assembler-inl.h"
#include "src/deoptimizer/deoptimizer.h"
#include "src/diagnostics/disassembler.h"
#include "src/execution/isolate.h"
#include "src/heap/heap-inl.h" // For MemoryAllocator. TODO(jkummerow): Drop.
#include "src/snapshot/embedded/embedded-data.h"
#include "src/snapshot/snapshot.h"
#include "src/utils/ostreams.h"
namespace v8 {
namespace internal {
AssemblerOptions AssemblerOptions::Default(Isolate* isolate) {
AssemblerOptions options;
const bool serializer = isolate->serializer_enabled();
const bool generating_embedded_builtin =
isolate->IsGeneratingEmbeddedBuiltins();
options.record_reloc_info_for_serialization = serializer;
options.enable_root_relative_access =
!serializer && !generating_embedded_builtin;
#ifdef USE_SIMULATOR
// Even though the simulator is enabled, we may still need to generate code
// that may need to run on both the simulator and real hardware. For example,
// if we are cross-compiling and embedding a script into the snapshot, the
// script will need to run on the host causing the embedded builtins to run in
// the simulator. While the final cross-compiled V8 will not have a simulator.
// So here we enable simulator specific code if not generating the snapshot or
// if we are but we are targetting the simulator *only*.
options.enable_simulator_code = !serializer || v8_flags.target_is_simulator;
#endif
#if V8_TARGET_ARCH_X64 || V8_TARGET_ARCH_ARM64 || V8_TARGET_ARCH_LOONG64 || \
V8_TARGET_ARCH_RISCV64
options.code_range_base = isolate->heap()->code_range_base();
#endif
bool short_builtin_calls =
isolate->is_short_builtin_calls_enabled() &&
!generating_embedded_builtin &&
(options.code_range_base != kNullAddress) &&
// Serialization of NEAR_BUILTIN_ENTRY reloc infos is not supported yet.
!serializer;
if (short_builtin_calls) {
options.builtin_call_jump_mode = BuiltinCallJumpMode::kPCRelative;
}
return options;
}
namespace {
class DefaultAssemblerBuffer : public AssemblerBuffer {
public:
explicit DefaultAssemblerBuffer(int size)
: buffer_(base::OwnedVector<uint8_t>::NewForOverwrite(
std::max(AssemblerBase::kMinimalBufferSize, size))) {
#ifdef DEBUG
ZapCode(reinterpret_cast<Address>(buffer_.begin()), buffer_.size());
#endif
}
uint8_t* start() const override { return buffer_.begin(); }
int size() const override { return static_cast<int>(buffer_.size()); }
std::unique_ptr<AssemblerBuffer> Grow(int new_size) override {
DCHECK_LT(size(), new_size);
return std::make_unique<DefaultAssemblerBuffer>(new_size);
}
private:
base::OwnedVector<uint8_t> buffer_;
};
class ExternalAssemblerBufferImpl : public AssemblerBuffer {
public:
ExternalAssemblerBufferImpl(uint8_t* start, int size)
: start_(start), size_(size) {}
uint8_t* start() const override { return start_; }
int size() const override { return size_; }
std::unique_ptr<AssemblerBuffer> Grow(int new_size) override {
FATAL("Cannot grow external assembler buffer");
}
void* operator new(std::size_t count);
void operator delete(void* ptr) noexcept;
private:
uint8_t* const start_;
const int size_;
};
alignas(
ExternalAssemblerBufferImpl) static thread_local char tls_singleton_storage
[sizeof(ExternalAssemblerBufferImpl)];
static thread_local bool tls_singleton_taken{false};
void* ExternalAssemblerBufferImpl::operator new(std::size_t count) {
DCHECK_EQ(count, sizeof(ExternalAssemblerBufferImpl));
if (V8_LIKELY(!tls_singleton_taken)) {
tls_singleton_taken = true;
return tls_singleton_storage;
}
return ::operator new(count);
}
void ExternalAssemblerBufferImpl::operator delete(void* ptr) noexcept {
if (V8_LIKELY(ptr == tls_singleton_storage)) {
DCHECK(tls_singleton_taken);
tls_singleton_taken = false;
return;
}
::operator delete(ptr);
}
} // namespace
std::unique_ptr<AssemblerBuffer> ExternalAssemblerBuffer(void* start,
int size) {
return std::make_unique<ExternalAssemblerBufferImpl>(
reinterpret_cast<uint8_t*>(start), size);
}
std::unique_ptr<AssemblerBuffer> NewAssemblerBuffer(int size) {
return std::make_unique<DefaultAssemblerBuffer>(size);
}
// -----------------------------------------------------------------------------
// Implementation of AssemblerBase
// static
constexpr int AssemblerBase::kMinimalBufferSize;
// static
constexpr int AssemblerBase::kDefaultBufferSize;
AssemblerBase::AssemblerBase(const AssemblerOptions& options,
std::unique_ptr<AssemblerBuffer> buffer)
: buffer_(std::move(buffer)),
options_(options),
enabled_cpu_features_(0),
predictable_code_size_(false),
constant_pool_available_(false),
jump_optimization_info_(nullptr) {
if (!buffer_) buffer_ = NewAssemblerBuffer(kDefaultBufferSize);
buffer_start_ = buffer_->start();
pc_ = buffer_start_;
}
AssemblerBase::~AssemblerBase() = default;
void AssemblerBase::Print(Isolate* isolate) {
StdoutStream os;
v8::internal::Disassembler::Decode(isolate, os, buffer_start_, pc_);
}
// -----------------------------------------------------------------------------
// Implementation of CpuFeatureScope
#ifdef DEBUG
CpuFeatureScope::CpuFeatureScope(AssemblerBase* assembler, CpuFeature f,
CheckPolicy check)
: assembler_(assembler) {
DCHECK_IMPLIES(check == kCheckSupported, CpuFeatures::IsSupported(f));
old_enabled_ = assembler_->enabled_cpu_features();
assembler_->EnableCpuFeature(f);
}
CpuFeatureScope::~CpuFeatureScope() {
assembler_->set_enabled_cpu_features(old_enabled_);
}
#endif
bool CpuFeatures::initialized_ = false;
bool CpuFeatures::supports_wasm_simd_128_ = false;
bool CpuFeatures::supports_cetss_ = false;
unsigned CpuFeatures::supported_ = 0;
unsigned CpuFeatures::icache_line_size_ = 0;
unsigned CpuFeatures::dcache_line_size_ = 0;
HeapNumberRequest::HeapNumberRequest(double heap_number, int offset)
: offset_(offset) {
value_ = heap_number;
DCHECK(!IsSmiDouble(value_));
}
// Platform specific but identical code for all the platforms.
void Assembler::RecordDeoptReason(DeoptimizeReason reason, uint32_t node_id,
SourcePosition position, int id) {
static_assert(RelocInfoWriter::kMaxSize * 2 <= kGap);
{
EnsureSpace space(this);
DCHECK(position.IsKnown());
RecordRelocInfo(RelocInfo::DEOPT_SCRIPT_OFFSET, position.ScriptOffset());
RecordRelocInfo(RelocInfo::DEOPT_INLINING_ID, position.InliningId());
}
{
EnsureSpace space(this);
RecordRelocInfo(RelocInfo::DEOPT_REASON, static_cast<int>(reason));
RecordRelocInfo(RelocInfo::DEOPT_ID, id);
}
#ifdef DEBUG
EnsureSpace space(this);
RecordRelocInfo(RelocInfo::DEOPT_NODE_ID, node_id);
#endif // DEBUG
}
void Assembler::DataAlign(int m) {
DCHECK(m >= 2 && base::bits::IsPowerOfTwo(m));
while ((pc_offset() & (m - 1)) != 0) {
// Pad with 0xcc (= int3 on ia32 and x64); the primary motivation is that
// the disassembler expects to find valid instructions, but this is also
// nice from a security point of view.
db(0xcc);
}
}
void AssemblerBase::RequestHeapNumber(HeapNumberRequest request) {
request.set_offset(pc_offset());
heap_number_requests_.push_front(request);
}
int AssemblerBase::AddCodeTarget(IndirectHandle<Code> target) {
int current = static_cast<int>(code_targets_.size());
if (current > 0 && !target.is_null() &&
code_targets_.back().address() == target.address()) {
// Optimization if we keep jumping to the same code target.
return current - 1;
} else {
code_targets_.push_back(target);
return current;
}
}
IndirectHandle<Code> AssemblerBase::GetCodeTarget(
intptr_t code_target_index) const {
DCHECK_LT(static_cast<size_t>(code_target_index), code_targets_.size());
return code_targets_[code_target_index];
}
AssemblerBase::EmbeddedObjectIndex AssemblerBase::AddEmbeddedObject(
IndirectHandle<HeapObject> object) {
EmbeddedObjectIndex current = embedded_objects_.size();
// Do not deduplicate invalid handles, they are to heap object requests.
if (!object.is_null()) {
auto entry = embedded_objects_map_.find(object);
if (entry != embedded_objects_map_.end()) {
return entry->second;
}
embedded_objects_map_[object] = current;
}
embedded_objects_.push_back(object);
return current;
}
IndirectHandle<HeapObject> AssemblerBase::GetEmbeddedObject(
EmbeddedObjectIndex index) const {
DCHECK_LT(index, embedded_objects_.size());
return embedded_objects_[index];
}
int Assembler::WriteCodeComments() {
if (!v8_flags.code_comments) return 0;
CHECK_IMPLIES(code_comments_writer_.entry_count() > 0,
options().emit_code_comments);
if (code_comments_writer_.entry_count() == 0) return 0;
int offset = pc_offset();
code_comments_writer_.Emit(this);
int size = pc_offset() - offset;
DCHECK_EQ(size, code_comments_writer_.section_size());
return size;
}
#ifdef V8_CODE_COMMENTS
int Assembler::CodeComment::depth() const { return assembler_->comment_depth_; }
void Assembler::CodeComment::Open(const std::string& comment,
const SourceLocation& loc) {
std::stringstream sstream;
sstream << std::setfill(' ') << std::setw(depth() * kIndentWidth + 2);
sstream << "[ " << comment;
assembler_->comment_depth_++;
assembler_->RecordComment(sstream.str(), loc);
}
void Assembler::CodeComment::Close() {
assembler_->comment_depth_--;
std::string comment = "]";
comment.insert(0, depth() * kIndentWidth, ' ');
DCHECK_LE(0, depth());
// Don't record source information for the closed comment.
assembler_->RecordComment(comment, SourceLocation());
}
#endif
} // namespace internal
} // namespace v8