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dart / sdk.git / 1c69c696508fd4822d778582b7ae32c9d2932b5a / . / runtime / vm / image_snapshot.cc
blob: cb2ef41b3e97fbf4f3e837a6d588845389e983c7 [file] [log] [blame]
// Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "vm/image_snapshot.h"
#include "include/dart_api.h"
#include "platform/assert.h"
#include "vm/class_id.h"
#include "vm/compiler/runtime_api.h"
#include "vm/dwarf.h"
#include "vm/elf.h"
#include "vm/hash.h"
#include "vm/hash_map.h"
#include "vm/heap/heap.h"
#include "vm/instructions.h"
#include "vm/json_writer.h"
#include "vm/object.h"
#include "vm/object_store.h"
#include "vm/program_visitor.h"
#include "vm/stub_code.h"
#include "vm/timeline.h"
#include "vm/type_testing_stubs.h"
#if !defined(DART_PRECOMPILED_RUNTIME)
#include "vm/compiler/backend/code_statistics.h"
#endif // !defined(DART_PRECOMPILED_RUNTIME)
namespace dart {
#if defined(DART_PRECOMPILER)
DEFINE_FLAG(bool,
print_instruction_stats,
false,
"Print instruction statistics");
DEFINE_FLAG(charp,
print_instructions_sizes_to,
NULL,
"Print sizes of all instruction objects to the given file");
#endif
intptr_t ObjectOffsetTrait::Hashcode(Key key) {
ObjectPtr obj = key;
ASSERT(!obj->IsSmi());
uword body = ObjectLayout::ToAddr(obj) + sizeof(ObjectLayout);
uword end = ObjectLayout::ToAddr(obj) + obj->ptr()->HeapSize();
uint32_t hash = obj->GetClassId();
// Don't include the header. Objects in the image are pre-marked, but objects
// in the current isolate are not.
for (uword cursor = body; cursor < end; cursor += sizeof(uint32_t)) {
hash = CombineHashes(hash, *reinterpret_cast<uint32_t*>(cursor));
}
return FinalizeHash(hash, 30);
}
bool ObjectOffsetTrait::IsKeyEqual(Pair pair, Key key) {
ObjectPtr a = pair.object;
ObjectPtr b = key;
ASSERT(!a->IsSmi());
ASSERT(!b->IsSmi());
if (a->GetClassId() != b->GetClassId()) {
return false;
}
intptr_t heap_size = a->ptr()->HeapSize();
if (b->ptr()->HeapSize() != heap_size) {
return false;
}
// Don't include the header. Objects in the image are pre-marked, but objects
// in the current isolate are not.
uword body_a = ObjectLayout::ToAddr(a) + sizeof(ObjectLayout);
uword body_b = ObjectLayout::ToAddr(b) + sizeof(ObjectLayout);
uword body_size = heap_size - sizeof(ObjectLayout);
return 0 == memcmp(reinterpret_cast<const void*>(body_a),
reinterpret_cast<const void*>(body_b), body_size);
}
#if !defined(DART_PRECOMPILED_RUNTIME)
ImageWriter::ImageWriter(Thread* t)
: heap_(t->heap()),
next_data_offset_(0),
next_text_offset_(0),
objects_(),
instructions_(),
instructions_section_type_(
TagObjectTypeAsReadOnly(t->zone(), "InstructionsSection")),
instructions_type_(TagObjectTypeAsReadOnly(t->zone(), "Instructions")),
trampoline_type_(TagObjectTypeAsReadOnly(t->zone(), "Trampoline")) {
ResetOffsets();
}
void ImageWriter::PrepareForSerialization(
GrowableArray<ImageWriterCommand>* commands) {
if (commands != nullptr) {
const intptr_t initial_offset = next_text_offset_;
for (auto& inst : *commands) {
ASSERT((initial_offset + inst.expected_offset) == next_text_offset_);
switch (inst.op) {
case ImageWriterCommand::InsertInstructionOfCode: {
CodePtr code = inst.insert_instruction_of_code.code;
InstructionsPtr instructions = Code::InstructionsOf(code);
const intptr_t offset = next_text_offset_;
instructions_.Add(InstructionsData(instructions, code, offset));
next_text_offset_ += SizeInSnapshot(instructions);
ASSERT(heap_->GetObjectId(instructions) == 0);
heap_->SetObjectId(instructions, offset);
break;
}
case ImageWriterCommand::InsertBytesOfTrampoline: {
auto trampoline_bytes = inst.insert_trampoline_bytes.buffer;
auto trampoline_length = inst.insert_trampoline_bytes.buffer_length;
const intptr_t offset = next_text_offset_;
instructions_.Add(
InstructionsData(trampoline_bytes, trampoline_length, offset));
next_text_offset_ += trampoline_length;
break;
}
default:
UNREACHABLE();
}
}
}
}
int32_t ImageWriter::GetTextOffsetFor(InstructionsPtr instructions,
CodePtr code) {
intptr_t offset = heap_->GetObjectId(instructions);
if (offset != 0) {
return offset;
}
offset = next_text_offset_;
heap_->SetObjectId(instructions, offset);
next_text_offset_ += SizeInSnapshot(instructions);
instructions_.Add(InstructionsData(instructions, code, offset));
ASSERT(offset != 0);
return offset;
}
static intptr_t InstructionsSizeInSnapshot(InstructionsPtr raw) {
if (FLAG_precompiled_mode && FLAG_use_bare_instructions) {
// Currently, we align bare instruction payloads on 4 byte boundaries.
//
// If we later decide to align on larger boundaries to put entries at the
// start of cache lines, make sure to account for entry points that are
// _not_ at the start of the payload.
return Utils::RoundUp(Instructions::Size(raw),
ImageWriter::kBareInstructionsAlignment);
}
#if defined(IS_SIMARM_X64)
return Utils::RoundUp(
compiler::target::Instructions::HeaderSize() + Instructions::Size(raw),
compiler::target::ObjectAlignment::kObjectAlignment);
#else
return raw->ptr()->HeapSize();
#endif
}
#if defined(IS_SIMARM_X64)
static intptr_t CompressedStackMapsSizeInSnapshot(intptr_t payload_size) {
const intptr_t unrounded_size_in_bytes =
compiler::target::CompressedStackMaps::HeaderSize() + payload_size;
return Utils::RoundUp(unrounded_size_in_bytes,
compiler::target::ObjectAlignment::kObjectAlignment);
}
static intptr_t StringPayloadSize(intptr_t len, bool isOneByteString) {
return len * (isOneByteString ? OneByteString::kBytesPerElement
: TwoByteString::kBytesPerElement);
}
static intptr_t StringSizeInSnapshot(intptr_t len, bool isOneByteString) {
const intptr_t unrounded_size_in_bytes =
(String::kSizeofRawString / 2) + StringPayloadSize(len, isOneByteString);
return Utils::RoundUp(unrounded_size_in_bytes,
compiler::target::ObjectAlignment::kObjectAlignment);
}
static intptr_t CodeSourceMapSizeInSnapshot(intptr_t len) {
const intptr_t unrounded_size_in_bytes =
2 * compiler::target::kWordSize + len;
return Utils::RoundUp(unrounded_size_in_bytes,
compiler::target::ObjectAlignment::kObjectAlignment);
}
static intptr_t PcDescriptorsSizeInSnapshot(intptr_t len) {
const intptr_t unrounded_size_in_bytes =
2 * compiler::target::kWordSize + len;
return Utils::RoundUp(unrounded_size_in_bytes,
compiler::target::ObjectAlignment::kObjectAlignment);
}
intptr_t ImageWriter::SizeInSnapshot(ObjectPtr raw_object) {
const classid_t cid = raw_object->GetClassId();
switch (cid) {
case kCompressedStackMapsCid: {
CompressedStackMapsPtr raw_maps =
static_cast<CompressedStackMapsPtr>(raw_object);
auto const payload_size = CompressedStackMaps::PayloadSizeOf(raw_maps);
return CompressedStackMapsSizeInSnapshot(payload_size);
}
case kOneByteStringCid:
case kTwoByteStringCid: {
StringPtr raw_str = static_cast<StringPtr>(raw_object);
return StringSizeInSnapshot(Smi::Value(raw_str->ptr()->length_),
cid == kOneByteStringCid);
}
case kCodeSourceMapCid: {
CodeSourceMapPtr raw_map = static_cast<CodeSourceMapPtr>(raw_object);
return CodeSourceMapSizeInSnapshot(raw_map->ptr()->length_);
}
case kPcDescriptorsCid: {
PcDescriptorsPtr raw_desc = static_cast<PcDescriptorsPtr>(raw_object);
return PcDescriptorsSizeInSnapshot(raw_desc->ptr()->length_);
}
case kInstructionsCid: {
InstructionsPtr raw_insns = static_cast<InstructionsPtr>(raw_object);
return InstructionsSizeInSnapshot(raw_insns);
}
default: {
const Class& clazz = Class::Handle(Object::Handle(raw_object).clazz());
FATAL1("Unsupported class %s in rodata section.\n", clazz.ToCString());
return 0;
}
}
}
#else // defined(IS_SIMARM_X64)
intptr_t ImageWriter::SizeInSnapshot(ObjectPtr raw) {
switch (raw->GetClassId()) {
case kInstructionsCid:
return InstructionsSizeInSnapshot(static_cast<InstructionsPtr>(raw));
default:
return raw->ptr()->HeapSize();
}
}
#endif // defined(IS_SIMARM_X64)
uint32_t ImageWriter::GetDataOffsetFor(ObjectPtr raw_object) {
intptr_t snap_size = SizeInSnapshot(raw_object);
intptr_t offset = next_data_offset_;
next_data_offset_ += snap_size;
objects_.Add(ObjectData(raw_object));
return offset;
}
intptr_t ImageWriter::GetTextObjectCount() const {
return instructions_.length();
}
void ImageWriter::GetTrampolineInfo(intptr_t* count, intptr_t* size) const {
ASSERT(count != nullptr && size != nullptr);
*count = 0;
*size = 0;
for (auto const data : instructions_) {
if (data.trampoline_length != 0) {
*count += 1;
*size += data.trampoline_length;
}
}
}
// Returns nullptr if there is no profile writer.
const char* ImageWriter::ObjectTypeForProfile(const Object& object) const {
if (profile_writer_ == nullptr) return nullptr;
ASSERT(IsROSpace());
Thread* thread = Thread::Current();
REUSABLE_CLASS_HANDLESCOPE(thread);
REUSABLE_STRING_HANDLESCOPE(thread);
Class& klass = thread->ClassHandle();
String& name = thread->StringHandle();
klass = object.clazz();
name = klass.UserVisibleName();
auto const name_str = name.ToCString();
return TagObjectTypeAsReadOnly(thread->zone(), name_str);
}
const char* ImageWriter::TagObjectTypeAsReadOnly(Zone* zone, const char* type) {
ASSERT(zone != nullptr && type != nullptr);
return OS::SCreate(zone, "(RO) %s", type);
}
#if defined(DART_PRECOMPILER)
void ImageWriter::DumpInstructionStats() {
std::unique_ptr<CombinedCodeStatistics> instruction_stats(
new CombinedCodeStatistics());
for (intptr_t i = 0; i < instructions_.length(); i++) {
auto& data = instructions_[i];
CodeStatistics* stats = data.insns_->stats();
if (stats != nullptr) {
stats->AppendTo(instruction_stats.get());
}
}
instruction_stats->DumpStatistics();
}
void ImageWriter::DumpInstructionsSizes() {
auto thread = Thread::Current();
auto zone = thread->zone();
auto& cls = Class::Handle(zone);
auto& lib = Library::Handle(zone);
auto& owner = Object::Handle(zone);
auto& url = String::Handle(zone);
auto& name = String::Handle(zone);
intptr_t trampolines_total_size = 0;
JSONWriter js;
js.OpenArray();
for (intptr_t i = 0; i < instructions_.length(); i++) {
auto& data = instructions_[i];
const bool is_trampoline = data.code_ == nullptr;
if (is_trampoline) {
trampolines_total_size += data.trampoline_length;
continue;
}
owner = WeakSerializationReference::Unwrap(data.code_->owner());
js.OpenObject();
if (owner.IsFunction()) {
cls = Function::Cast(owner).Owner();
name = cls.ScrubbedName();
lib = cls.library();
url = lib.url();
js.PrintPropertyStr("l", url);
js.PrintPropertyStr("c", name);
} else if (owner.IsClass()) {
cls ^= owner.raw();
name = cls.ScrubbedName();
lib = cls.library();
js.PrintPropertyStr("l", url);
js.PrintPropertyStr("c", name);
}
js.PrintProperty("n",
data.code_->QualifiedName(
NameFormattingParams::DisambiguatedWithoutClassName(
Object::kInternalName)));
js.PrintProperty("s", SizeInSnapshot(data.insns_->raw()));
js.CloseObject();
}
if (trampolines_total_size != 0) {
js.OpenObject();
js.PrintProperty("n", "[Stub] Trampoline");
js.PrintProperty("s", trampolines_total_size);
js.CloseObject();
}
js.CloseArray();
auto file_open = Dart::file_open_callback();
auto file_write = Dart::file_write_callback();
auto file_close = Dart::file_close_callback();
if ((file_open == nullptr) || (file_write == nullptr) ||
(file_close == nullptr)) {
return;
}
auto file = file_open(FLAG_print_instructions_sizes_to, /*write=*/true);
if (file == nullptr) {
OS::PrintErr("Failed to open file %s\n", FLAG_print_instructions_sizes_to);
return;
}
char* output = nullptr;
intptr_t output_length = 0;
js.Steal(&output, &output_length);
file_write(output, output_length, file);
free(output);
file_close(file);
}
void ImageWriter::DumpStatistics() {
if (FLAG_print_instruction_stats) {
DumpInstructionStats();
}
if (FLAG_print_instructions_sizes_to != nullptr) {
DumpInstructionsSizes();
}
}
#endif
void ImageWriter::Write(WriteStream* clustered_stream, bool vm) {
Thread* thread = Thread::Current();
Zone* zone = thread->zone();
Heap* heap = thread->isolate()->heap();
TIMELINE_DURATION(thread, Isolate, "WriteInstructions");
// Handlify collected raw pointers as building the names below
// will allocate on the Dart heap.
for (intptr_t i = 0; i < instructions_.length(); i++) {
InstructionsData& data = instructions_[i];
const bool is_trampoline = data.trampoline_bytes != nullptr;
if (is_trampoline) continue;
data.insns_ = &Instructions::Handle(zone, data.raw_insns_);
ASSERT(data.raw_code_ != nullptr);
data.code_ = &Code::Handle(zone, data.raw_code_);
// Reset object id as an isolate snapshot after a VM snapshot will not use
// the VM snapshot's text image.
heap->SetObjectId(data.insns_->raw(), 0);
}
for (intptr_t i = 0; i < objects_.length(); i++) {
ObjectData& data = objects_[i];
data.obj_ = &Object::Handle(zone, data.raw_obj_);
}
// Append the direct-mapped RO data objects after the clustered snapshot.
// We need to do this before WriteText because WriteText currently adds the
// finalized contents of the clustered_stream as data sections.
offset_space_ = vm ? V8SnapshotProfileWriter::kVmData
: V8SnapshotProfileWriter::kIsolateData;
WriteROData(clustered_stream);
offset_space_ = vm ? V8SnapshotProfileWriter::kVmText
: V8SnapshotProfileWriter::kIsolateText;
// Needs to happen after WriteROData, because all image writers currently
// add the clustered data information to their output in WriteText().
WriteText(clustered_stream, vm);
}
void ImageWriter::WriteROData(WriteStream* stream) {
#if defined(DART_PRECOMPILER)
const intptr_t start_position = stream->Position();
#endif
stream->Align(kMaxObjectAlignment);
// Heap page starts here.
intptr_t section_start = stream->Position();
stream->WriteWord(next_data_offset_); // Data length.
// Zero values for other image header fields.
stream->Align(kMaxObjectAlignment);
ASSERT(stream->Position() - section_start == Image::kHeaderSize);
#if defined(DART_PRECOMPILER)
if (profile_writer_ != nullptr) {
const intptr_t end_position = stream->Position();
profile_writer_->AttributeBytesTo(
V8SnapshotProfileWriter::ArtificialRootId(),
end_position - start_position);
}
#endif
// Heap page objects start here.
for (intptr_t i = 0; i < objects_.length(); i++) {
const Object& obj = *objects_[i].obj_;
AutoTraceImage(obj, section_start, stream);
NoSafepointScope no_safepoint;
uword start = static_cast<uword>(obj.raw()) - kHeapObjectTag;
// Write object header with the mark and read-only bits set.
uword marked_tags = obj.raw()->ptr()->tags_;
marked_tags = ObjectLayout::OldBit::update(true, marked_tags);
marked_tags = ObjectLayout::OldAndNotMarkedBit::update(false, marked_tags);
marked_tags =
ObjectLayout::OldAndNotRememberedBit::update(true, marked_tags);
marked_tags = ObjectLayout::NewBit::update(false, marked_tags);
#if defined(HASH_IN_OBJECT_HEADER)
marked_tags |= static_cast<uword>(obj.raw()->ptr()->hash_) << 32;
#endif
#if defined(IS_SIMARM_X64)
if (obj.IsCompressedStackMaps()) {
const CompressedStackMaps& map = CompressedStackMaps::Cast(obj);
auto const object_start = stream->Position();
const intptr_t payload_size = map.payload_size();
const intptr_t size_in_bytes =
CompressedStackMapsSizeInSnapshot(payload_size);
marked_tags = UpdateObjectSizeForTarget(size_in_bytes, marked_tags);
stream->WriteTargetWord(marked_tags);
stream->WriteFixed<uint32_t>(map.raw()->ptr()->flags_and_size_);
ASSERT_EQUAL(stream->Position() - object_start,
compiler::target::CompressedStackMaps::HeaderSize());
stream->WriteBytes(map.raw()->ptr()->data(), payload_size);
stream->Align(compiler::target::ObjectAlignment::kObjectAlignment);
} else if (obj.IsString()) {
const String& str = String::Cast(obj);
RELEASE_ASSERT(String::GetCachedHash(str.raw()) != 0);
RELEASE_ASSERT(str.IsOneByteString() || str.IsTwoByteString());
const intptr_t size_in_bytes =
StringSizeInSnapshot(str.Length(), str.IsOneByteString());
marked_tags = UpdateObjectSizeForTarget(size_in_bytes, marked_tags);
stream->WriteTargetWord(marked_tags);
stream->WriteTargetWord(static_cast<uword>(str.raw()->ptr()->length_));
stream->WriteTargetWord(static_cast<uword>(str.raw()->ptr()->hash_));
stream->WriteBytes(
reinterpret_cast<const void*>(start + String::kSizeofRawString),
StringPayloadSize(str.Length(), str.IsOneByteString()));
stream->Align(compiler::target::ObjectAlignment::kObjectAlignment);
} else if (obj.IsCodeSourceMap()) {
const CodeSourceMap& map = CodeSourceMap::Cast(obj);
const intptr_t size_in_bytes = CodeSourceMapSizeInSnapshot(map.Length());
marked_tags = UpdateObjectSizeForTarget(size_in_bytes, marked_tags);
stream->WriteTargetWord(marked_tags);
stream->WriteTargetWord(map.Length());
stream->WriteBytes(map.Data(), map.Length());
stream->Align(compiler::target::ObjectAlignment::kObjectAlignment);
} else if (obj.IsPcDescriptors()) {
const PcDescriptors& desc = PcDescriptors::Cast(obj);
const intptr_t size_in_bytes = PcDescriptorsSizeInSnapshot(desc.Length());
marked_tags = UpdateObjectSizeForTarget(size_in_bytes, marked_tags);
stream->WriteTargetWord(marked_tags);
stream->WriteTargetWord(desc.Length());
stream->WriteBytes(desc.raw()->ptr()->data(), desc.Length());
stream->Align(compiler::target::ObjectAlignment::kObjectAlignment);
} else {
const Class& clazz = Class::Handle(obj.clazz());
FATAL1("Unsupported class %s in rodata section.\n", clazz.ToCString());
}
#else // defined(IS_SIMARM_X64)
const uword end = start + obj.raw()->ptr()->HeapSize();
stream->WriteWord(marked_tags);
start += sizeof(uword);
for (uword* cursor = reinterpret_cast<uword*>(start);
cursor < reinterpret_cast<uword*>(end); cursor++) {
stream->WriteWord(*cursor);
}
#endif // defined(IS_SIMARM_X64)
}
}
#if defined(DART_PRECOMPILER)
class DwarfAssemblyStream : public DwarfWriteStream {
public:
explicit DwarfAssemblyStream(StreamingWriteStream* stream)
: stream_(ASSERT_NOTNULL(stream)) {}
void sleb128(intptr_t value) { Print(".sleb128 %" Pd "\n", value); }
void uleb128(uintptr_t value) { Print(".uleb128 %" Pd "\n", value); }
void u1(uint8_t value) { Print(".byte %u\n", value); }
void u2(uint16_t value) { Print(".2byte %u\n", value); }
void u4(uint32_t value) { Print(".4byte %" Pu32 "\n", value); }
void u8(uint64_t value) { Print(".8byte %" Pu64 "\n", value); }
void string(const char* cstr) { // NOLINT
Print(".string \"%s\"\n", cstr); // NOLINT
}
// Uses labels, so doesn't output to start or return a useful fixup position.
intptr_t ReserveSize(const char* prefix, intptr_t* start) {
// Assignment to temp works around buggy Mac assembler.
Print("L%s_size = .L%s_end - .L%s_start\n", prefix, prefix, prefix);
Print(".4byte L%s_size\n", prefix);
Print(".L%s_start:\n", prefix);
return -1;
}
// Just need to label the end so the assembler can calculate the size, so
// start and the fixup position is unused.
void SetSize(intptr_t fixup, const char* prefix, intptr_t start) {
Print(".L%s_end:\n", prefix);
}
void OffsetFromSymbol(const char* symbol, intptr_t offset) {
if (offset == 0) {
PrintNamedAddress(symbol);
} else {
PrintNamedAddressWithOffset(symbol, offset);
}
}
void DistanceBetweenSymbolOffsets(const char* symbol1,
intptr_t offset1,
const char* symbol2,
intptr_t offset2) {
Print(".uleb128 %s - %s + %" Pd "\n", symbol1, symbol2, offset1 - offset2);
}
// No-op, we'll be using labels.
void InitializeAbstractOrigins(intptr_t size) {}
void RegisterAbstractOrigin(intptr_t index) {
// Label for DW_AT_abstract_origin references
Print(".Lfunc%" Pd ":\n", index);
}
void AbstractOrigin(intptr_t index) {
// Assignment to temp works around buggy Mac assembler.
Print("Ltemp%" Pd " = .Lfunc%" Pd " - %s\n", temp_, index, kDebugInfoLabel);
Print(".4byte Ltemp%" Pd "\n", temp_);
temp_++;
}
// Methods for writing the assembly prologues for various DWARF sections.
void AbbreviationsPrologue() {
#if defined(TARGET_OS_MACOS) || defined(TARGET_OS_MACOS_IOS)
Print(".section __DWARF,__debug_abbrev,regular,debug\n");
#elif defined(TARGET_OS_LINUX) || defined(TARGET_OS_ANDROID) || \
defined(TARGET_OS_FUCHSIA)
Print(".section .debug_abbrev,\"\"\n");
#else
UNIMPLEMENTED();
#endif
}
void DebugInfoPrologue() {
#if defined(TARGET_OS_MACOS) || defined(TARGET_OS_MACOS_IOS)
Print(".section __DWARF,__debug_info,regular,debug\n");
#elif defined(TARGET_OS_LINUX) || defined(TARGET_OS_ANDROID) || \
defined(TARGET_OS_FUCHSIA)
Print(".section .debug_info,\"\"\n");
#else
UNIMPLEMENTED();
#endif
// Used to calculate abstract origin values.
Print("%s:\n", kDebugInfoLabel);
}
void LineNumberProgramPrologue() {
#if defined(TARGET_OS_MACOS) || defined(TARGET_OS_MACOS_IOS)
Print(".section __DWARF,__debug_line,regular,debug\n");
#elif defined(TARGET_OS_LINUX) || defined(TARGET_OS_ANDROID) || \
defined(TARGET_OS_FUCHSIA)
Print(".section .debug_line,\"\"\n");
#else
UNIMPLEMENTED();
#endif
}
private:
static constexpr const char* kDebugInfoLabel = ".Ldebug_info";
void Print(const char* format, ...) PRINTF_ATTRIBUTE(2, 3) {
va_list args;
va_start(args, format);
stream_->VPrint(format, args);
va_end(args);
}
#if defined(TARGET_ARCH_IS_32_BIT)
#define FORM_ADDR ".4byte"
#elif defined(TARGET_ARCH_IS_64_BIT)
#define FORM_ADDR ".8byte"
#endif
void PrintNamedAddress(const char* name) { Print(FORM_ADDR " %s\n", name); }
void PrintNamedAddressWithOffset(const char* name, intptr_t offset) {
Print(FORM_ADDR " %s + %" Pd "\n", name, offset);
}
#undef FORM_ADDR
StreamingWriteStream* const stream_;
intptr_t temp_ = 0;
DISALLOW_COPY_AND_ASSIGN(DwarfAssemblyStream);
};
#endif
static inline Dwarf* AddDwarfIfUnstripped(Zone* zone, bool strip, Elf* elf) {
#if defined(DART_PRECOMPILER)
if (!strip) {
if (elf != nullptr) {
// Reuse the existing DWARF object.
ASSERT(elf->dwarf() != nullptr);
return elf->dwarf();
}
return new (zone) Dwarf(zone);
}
#endif
return nullptr;
}
AssemblyImageWriter::AssemblyImageWriter(Thread* thread,
Dart_StreamingWriteCallback callback,
void* callback_data,
bool strip,
Elf* debug_elf)
: ImageWriter(thread),
assembly_stream_(512 * KB, callback, callback_data),
assembly_dwarf_(AddDwarfIfUnstripped(thread->zone(), strip, debug_elf)),
debug_elf_(debug_elf) {}
void AssemblyImageWriter::Finalize() {
#if defined(DART_PRECOMPILER)
if (assembly_dwarf_ != nullptr) {
DwarfAssemblyStream dwarf_stream(&assembly_stream_);
dwarf_stream.AbbreviationsPrologue();
assembly_dwarf_->WriteAbbreviations(&dwarf_stream);
dwarf_stream.DebugInfoPrologue();
assembly_dwarf_->WriteDebugInfo(&dwarf_stream);
dwarf_stream.LineNumberProgramPrologue();
assembly_dwarf_->WriteLineNumberProgram(&dwarf_stream);
}
if (debug_elf_ != nullptr) {
debug_elf_->Finalize();
}
#endif
}
#if !defined(DART_PRECOMPILED_RUNTIME)
static void EnsureAssemblerIdentifier(char* label) {
for (char c = *label; c != '\0'; c = *++label) {
if (((c >= 'a') && (c <= 'z')) || ((c >= 'A') && (c <= 'Z')) ||
((c >= '0') && (c <= '9'))) {
continue;
}
*label = '_';
}
}
#endif // !defined(DART_PRECOMPILED_RUNTIME)
const char* SnapshotTextObjectNamer::SnapshotNameFor(intptr_t code_index,
const Code& code) {
ASSERT(!code.IsNull());
const char* prefix = FLAG_precompiled_mode ? "Precompiled_" : "";
owner_ = code.owner();
if (owner_.IsNull()) {
insns_ = code.instructions();
const char* name = StubCode::NameOfStub(insns_.EntryPoint());
ASSERT(name != nullptr);
return OS::SCreate(zone_, "%sStub_%s", prefix, name);
}
// The weak reference to the Code's owner should never have been removed via
// an intermediate serialization, since WSRs are only introduced during
// precompilation.
owner_ = WeakSerializationReference::Unwrap(owner_);
ASSERT(!owner_.IsNull());
if (owner_.IsClass()) {
string_ = Class::Cast(owner_).Name();
const char* name = string_.ToCString();
EnsureAssemblerIdentifier(const_cast<char*>(name));
return OS::SCreate(zone_, "%sAllocationStub_%s_%" Pd, prefix, name,
code_index);
} else if (owner_.IsAbstractType()) {
const char* name = namer_.StubNameForType(AbstractType::Cast(owner_));
return OS::SCreate(zone_, "%s%s_%" Pd, prefix, name, code_index);
} else if (owner_.IsFunction()) {
const char* name = Function::Cast(owner_).ToQualifiedCString();
EnsureAssemblerIdentifier(const_cast<char*>(name));
return OS::SCreate(zone_, "%s%s_%" Pd, prefix, name, code_index);
} else {
UNREACHABLE();
}
}
const char* SnapshotTextObjectNamer::SnapshotNameFor(
intptr_t index,
const ImageWriter::InstructionsData& data) {
if (data.trampoline_bytes != nullptr) {
return OS::SCreate(zone_, "Trampoline_%" Pd "", index);
}
return SnapshotNameFor(index, *data.code_);
}
void AssemblyImageWriter::WriteText(WriteStream* clustered_stream, bool vm) {
#if defined(DART_PRECOMPILED_RUNTIME)
UNREACHABLE();
#else
Zone* zone = Thread::Current()->zone();
const bool bare_instruction_payloads =
FLAG_precompiled_mode && FLAG_use_bare_instructions;
#if defined(DART_PRECOMPILER)
const char* bss_symbol =
vm ? "_kDartVmSnapshotBss" : "_kDartIsolateSnapshotBss";
intptr_t debug_segment_base = 0;
if (debug_elf_ != nullptr) {
debug_segment_base = debug_elf_->NextMemoryOffset();
}
#endif
const char* instructions_symbol = vm ? kVmSnapshotInstructionsAsmSymbol
: kIsolateSnapshotInstructionsAsmSymbol;
assembly_stream_.Print(".text\n");
assembly_stream_.Print(".globl %s\n", instructions_symbol);
// Start snapshot at page boundary.
ASSERT(VirtualMemory::PageSize() >= kMaxObjectAlignment);
ASSERT(VirtualMemory::PageSize() >= Image::kBssAlignment);
Align(VirtualMemory::PageSize());
assembly_stream_.Print("%s:\n", instructions_symbol);
intptr_t text_offset = 0;
#if defined(DART_PRECOMPILER)
// Parent used for later profile objects. Starts off as the Image. When
// writing bare instructions payloads, this is later updated with the
// InstructionsSection object which contains all the bare payloads.
V8SnapshotProfileWriter::ObjectId parent_id(offset_space_, text_offset);
#endif
// This head also provides the gap to make the instructions snapshot
// look like a OldPage.
const intptr_t image_size = Utils::RoundUp(
next_text_offset_, compiler::target::ObjectAlignment::kObjectAlignment);
text_offset += WriteWordLiteralText(image_size);
#if defined(DART_PRECOMPILER)
assembly_stream_.Print("%s %s - %s\n", kLiteralPrefix, bss_symbol,
instructions_symbol);
text_offset += compiler::target::kWordSize;
#else
text_offset += WriteWordLiteralText(0); // No relocations.
#endif
text_offset += Align(kMaxObjectAlignment, text_offset);
ASSERT_EQUAL(text_offset, Image::kHeaderSize);
#if defined(DART_PRECOMPILER)
if (profile_writer_ != nullptr) {
profile_writer_->SetObjectTypeAndName(parent_id, "Image",
instructions_symbol);
// Assign post-instruction padding to the Image, unless we're writing bare
// instruction payloads, in which case we'll assign it to the
// InstructionsSection object.
const intptr_t padding =
bare_instruction_payloads ? 0 : image_size - next_text_offset_;
profile_writer_->AttributeBytesTo(parent_id, Image::kHeaderSize + padding);
profile_writer_->AddRoot(parent_id);
}
#endif
if (bare_instruction_payloads) {
#if defined(DART_PRECOMPILER)
if (profile_writer_ != nullptr) {
const V8SnapshotProfileWriter::ObjectId id(offset_space_, text_offset);
profile_writer_->SetObjectTypeAndName(id, instructions_section_type_,
instructions_symbol);
const intptr_t padding = image_size - next_text_offset_;
profile_writer_->AttributeBytesTo(
id, compiler::target::InstructionsSection::HeaderSize() + padding);
const intptr_t element_offset = id.second - parent_id.second;
profile_writer_->AttributeReferenceTo(
parent_id,
{id, V8SnapshotProfileWriter::Reference::kElement, element_offset});
// Later objects will have the InstructionsSection as a parent.
parent_id = id;
}
#endif
const intptr_t section_size = image_size - text_offset;
// Add the RawInstructionsSection header.
const compiler::target::uword marked_tags =
ObjectLayout::OldBit::encode(true) |
ObjectLayout::OldAndNotMarkedBit::encode(false) |
ObjectLayout::OldAndNotRememberedBit::encode(true) |
ObjectLayout::NewBit::encode(false) |
ObjectLayout::SizeTag::encode(AdjustObjectSizeForTarget(section_size)) |
ObjectLayout::ClassIdTag::encode(kInstructionsSectionCid);
text_offset += WriteWordLiteralText(marked_tags);
// Calculated using next_text_offset_, which doesn't include post-payload
// padding to object alignment.
const intptr_t instructions_length =
next_text_offset_ - (text_offset + compiler::target::kWordSize);
text_offset += WriteWordLiteralText(instructions_length);
}
FrameUnwindPrologue();
PcDescriptors& descriptors = PcDescriptors::Handle(zone);
SnapshotTextObjectNamer namer(zone);
ASSERT(offset_space_ != V8SnapshotProfileWriter::kSnapshot);
for (intptr_t i = 0; i < instructions_.length(); i++) {
auto& data = instructions_[i];
const bool is_trampoline = data.trampoline_bytes != nullptr;
ASSERT_EQUAL(data.text_offset_, text_offset);
intptr_t dwarf_index = i;
#if defined(DART_PRECOMPILER)
if (!is_trampoline && assembly_dwarf_ != nullptr) {
dwarf_index =
assembly_dwarf_->AddCode(*data.code_, SegmentRelativeOffset(vm));
}
#endif
const auto object_name = namer.SnapshotNameFor(dwarf_index, data);
#if defined(DART_PRECOMPILER)
if (profile_writer_ != nullptr) {
const V8SnapshotProfileWriter::ObjectId id(offset_space_, text_offset);
auto const type = is_trampoline ? trampoline_type_ : instructions_type_;
const intptr_t size = is_trampoline ? data.trampoline_length
: SizeInSnapshot(data.insns_->raw());
profile_writer_->SetObjectTypeAndName(id, type, object_name);
profile_writer_->AttributeBytesTo(id, size);
const intptr_t element_offset = id.second - parent_id.second;
profile_writer_->AttributeReferenceTo(
parent_id,
{id, V8SnapshotProfileWriter::Reference::kElement, element_offset});
}
#endif
if (is_trampoline) {
const auto start = reinterpret_cast<uword>(data.trampoline_bytes);
const auto end = start + data.trampoline_length;
text_offset += WriteByteSequence(start, end);
delete[] data.trampoline_bytes;
data.trampoline_bytes = nullptr;
continue;
}
const intptr_t instr_start = text_offset;
const auto& code = *data.code_;
const auto& insns = *data.insns_;
descriptors = code.pc_descriptors();
const uword payload_start = insns.PayloadStart();
// 1. Write from the object start to the payload start. This includes the
// object header and the fixed fields. Not written for AOT snapshots using
// bare instructions.
if (!bare_instruction_payloads) {
NoSafepointScope no_safepoint;
// Write Instructions with the mark and read-only bits set.
uword marked_tags = insns.raw_ptr()->tags_;
marked_tags = ObjectLayout::OldBit::update(true, marked_tags);
marked_tags =
ObjectLayout::OldAndNotMarkedBit::update(false, marked_tags);
marked_tags =
ObjectLayout::OldAndNotRememberedBit::update(true, marked_tags);
marked_tags = ObjectLayout::NewBit::update(false, marked_tags);
#if defined(HASH_IN_OBJECT_HEADER)
// Can't use GetObjectTagsAndHash because the update methods discard the
// high bits.
marked_tags |= static_cast<uword>(insns.raw_ptr()->hash_) << 32;
#endif
#if defined(IS_SIMARM_X64)
const intptr_t size_in_bytes = InstructionsSizeInSnapshot(insns.raw());
marked_tags = UpdateObjectSizeForTarget(size_in_bytes, marked_tags);
WriteWordLiteralText(marked_tags);
text_offset += sizeof(compiler::target::uword);
WriteWordLiteralText(insns.raw_ptr()->size_and_flags_);
text_offset += sizeof(compiler::target::uword);
#else // defined(IS_SIMARM_X64)
uword object_start = reinterpret_cast<uword>(insns.raw_ptr());
WriteWordLiteralText(marked_tags);
object_start += sizeof(uword);
text_offset += sizeof(uword);
text_offset += WriteByteSequence(object_start, payload_start);
#endif // defined(IS_SIMARM_X64)
ASSERT((text_offset - instr_start) ==
compiler::target::Instructions::HeaderSize());
}
#if defined(DART_PRECOMPILER)
if (debug_elf_ != nullptr) {
debug_elf_->dwarf()->AddCode(code, {vm, text_offset});
}
#endif
// 2. Write a label at the entry point.
// Linux's perf uses these labels.
assembly_stream_.Print("%s:\n", object_name);
{
// 3. Write from the payload start to payload end. For AOT snapshots
// with bare instructions, this is the only part serialized.
NoSafepointScope no_safepoint;
assert(kBareInstructionsAlignment <=
compiler::target::ObjectAlignment::kObjectAlignment);
const auto payload_align = bare_instruction_payloads
? kBareInstructionsAlignment
: sizeof(compiler::target::uword);
const uword payload_size = Utils::RoundUp(insns.Size(), payload_align);
const uword payload_end = payload_start + payload_size;
ASSERT(Utils::IsAligned(text_offset, payload_align));
#if defined(DART_PRECOMPILER)
PcDescriptors::Iterator iterator(descriptors,
PcDescriptorsLayout::kBSSRelocation);
uword next_reloc_offset = iterator.MoveNext() ? iterator.PcOffset() : -1;
// We only generate BSS relocations that are word-sized and at
// word-aligned offsets in the payload.
auto const possible_relocations_end =
Utils::RoundDown(payload_end, sizeof(compiler::target::uword));
for (uword cursor = payload_start; cursor < possible_relocations_end;
cursor += sizeof(compiler::target::uword)) {
compiler::target::uword data =
*reinterpret_cast<compiler::target::uword*>(cursor);
if ((cursor - payload_start) == next_reloc_offset) {
assembly_stream_.Print("%s %s - (.) + %" Pd "\n", kLiteralPrefix,
bss_symbol, /*addend=*/data);
text_offset += compiler::target::kWordSize;
next_reloc_offset = iterator.MoveNext() ? iterator.PcOffset() : -1;
} else {
text_offset += WriteWordLiteralText(data);
}
}
assert(next_reloc_offset != (possible_relocations_end - payload_start));
text_offset += WriteByteSequence(possible_relocations_end, payload_end);
#else
text_offset += WriteByteSequence(payload_start, payload_end);
#endif
// 4. Write from the payload end to object end. Note we can't simply copy
// from the object because the host object may have less alignment filler
// than the target object in the cross-word case. Not written for AOT
// snapshots using bare instructions.
if (!bare_instruction_payloads) {
uword unaligned_size =
compiler::target::Instructions::HeaderSize() + payload_size;
uword alignment_size =
Utils::RoundUp(
unaligned_size,
compiler::target::ObjectAlignment::kObjectAlignment) -
unaligned_size;
while (alignment_size > 0) {
text_offset += WriteWordLiteralText(kBreakInstructionFiller);
alignment_size -= sizeof(compiler::target::uword);
}
ASSERT(kWordSize != compiler::target::kWordSize ||
(text_offset - instr_start) == insns.raw()->ptr()->HeapSize());
}
}
ASSERT((text_offset - instr_start) == SizeInSnapshot(insns.raw()));
}
// Should be a no-op unless writing bare instruction payloads, in which case
// we need to add post-payload padding to the object alignment. The alignment
// needs to match the one we used for image_size above.
text_offset +=
Align(compiler::target::ObjectAlignment::kObjectAlignment, text_offset);
ASSERT_EQUAL(text_offset, image_size);
FrameUnwindEpilogue();
#if defined(DART_PRECOMPILER)
if (debug_elf_ != nullptr) {
// We need to generate a text segment of the appropriate size in the ELF
// for two reasons:
//
// * We need unique virtual addresses for each text section in the DWARF
// file and that the virtual addresses for payloads within those sections
// do not overlap.
//
// * Our tools for converting DWARF stack traces back to "normal" Dart
// stack traces calculate an offset into the appropriate instructions
// section, and then add that offset to the virtual address of the
// corresponding segment to get the virtual address for the frame.
//
// Since we don't want to add the actual contents of the segment in the
// separate debugging information, we pass nullptr for the bytes, which
// creates an appropriate NOBITS section instead of PROGBITS.
auto const debug_segment_base2 = debug_elf_->AddText(
instructions_symbol, /*bytes=*/nullptr, text_offset);
// Double-check that no other ELF sections were added in the middle of
// writing the text section.
ASSERT(debug_segment_base2 == debug_segment_base);
}
assembly_stream_.Print(".bss\n");
// Align the BSS contents as expected by the Image class.
Align(Image::kBssAlignment);
assembly_stream_.Print("%s:\n", bss_symbol);
auto const entry_count = vm ? BSS::kVmEntryCount : BSS::kIsolateEntryCount;
for (intptr_t i = 0; i < entry_count; i++) {
WriteWordLiteralText(0);
}
#endif
#if defined(TARGET_OS_LINUX) || defined(TARGET_OS_ANDROID) || \
defined(TARGET_OS_FUCHSIA)
assembly_stream_.Print(".section .rodata\n");
#elif defined(TARGET_OS_MACOS) || defined(TARGET_OS_MACOS_IOS)
assembly_stream_.Print(".const\n");
#else
UNIMPLEMENTED();
#endif
const char* data_symbol =
vm ? kVmSnapshotDataAsmSymbol : kIsolateSnapshotDataAsmSymbol;
assembly_stream_.Print(".globl %s\n", data_symbol);
Align(kMaxObjectAlignment);
assembly_stream_.Print("%s:\n", data_symbol);
const uword buffer = reinterpret_cast<uword>(clustered_stream->buffer());
const intptr_t length = clustered_stream->bytes_written();
WriteByteSequence(buffer, buffer + length);
#if defined(DART_PRECOMPILER)
if (debug_elf_ != nullptr) {
// Add a NoBits section for the ROData as well.
debug_elf_->AddROData(data_symbol, clustered_stream->buffer(), length);
}
#endif // defined(DART_PRECOMPILER)
#endif // !defined(DART_PRECOMPILED_RUNTIME)
}
void AssemblyImageWriter::FrameUnwindPrologue() {
// Creates DWARF's .debug_frame
// CFI = Call frame information
// CFA = Canonical frame address
assembly_stream_.Print(".cfi_startproc\n");
#if defined(TARGET_ARCH_X64)
assembly_stream_.Print(".cfi_def_cfa rbp, 0\n"); // CFA is fp+0
assembly_stream_.Print(".cfi_offset rbp, 0\n"); // saved fp is *(CFA+0)
assembly_stream_.Print(".cfi_offset rip, 8\n"); // saved pc is *(CFA+8)
// saved sp is CFA+16
// Should be ".cfi_value_offset rsp, 16", but requires gcc newer than late
// 2016 and not supported by Android's libunwind.
// DW_CFA_expression 0x10
// uleb128 register (rsp) 7 (DWARF register number)
// uleb128 size of operation 2
// DW_OP_plus_uconst 0x23
// uleb128 addend 16
assembly_stream_.Print(".cfi_escape 0x10, 31, 2, 0x23, 16\n");
#elif defined(TARGET_ARCH_ARM64)
COMPILE_ASSERT(FP == R29);
COMPILE_ASSERT(LR == R30);
assembly_stream_.Print(".cfi_def_cfa x29, 0\n"); // CFA is fp+0
assembly_stream_.Print(".cfi_offset x29, 0\n"); // saved fp is *(CFA+0)
assembly_stream_.Print(".cfi_offset x30, 8\n"); // saved pc is *(CFA+8)
// saved sp is CFA+16
// Should be ".cfi_value_offset sp, 16", but requires gcc newer than late
// 2016 and not supported by Android's libunwind.
// DW_CFA_expression 0x10
// uleb128 register (x31) 31
// uleb128 size of operation 2
// DW_OP_plus_uconst 0x23
// uleb128 addend 16
assembly_stream_.Print(".cfi_escape 0x10, 31, 2, 0x23, 16\n");
#elif defined(TARGET_ARCH_ARM)
#if defined(TARGET_OS_MACOS) || defined(TARGET_OS_MACOS_IOS)
COMPILE_ASSERT(FP == R7);
assembly_stream_.Print(".cfi_def_cfa r7, 0\n"); // CFA is fp+j0
assembly_stream_.Print(".cfi_offset r7, 0\n"); // saved fp is *(CFA+0)
#else
COMPILE_ASSERT(FP == R11);
assembly_stream_.Print(".cfi_def_cfa r11, 0\n"); // CFA is fp+0
assembly_stream_.Print(".cfi_offset r11, 0\n"); // saved fp is *(CFA+0)
#endif
assembly_stream_.Print(".cfi_offset lr, 4\n"); // saved pc is *(CFA+4)
// saved sp is CFA+8
// Should be ".cfi_value_offset sp, 8", but requires gcc newer than late
// 2016 and not supported by Android's libunwind.
// DW_CFA_expression 0x10
// uleb128 register (sp) 13
// uleb128 size of operation 2
// DW_OP_plus_uconst 0x23
// uleb128 addend 8
assembly_stream_.Print(".cfi_escape 0x10, 13, 2, 0x23, 8\n");
// libunwind on ARM may use .ARM.exidx instead of .debug_frame
#if !defined(TARGET_OS_MACOS) && !defined(TARGET_OS_MACOS_IOS)
COMPILE_ASSERT(FP == R11);
assembly_stream_.Print(".fnstart\n");
assembly_stream_.Print(".save {r11, lr}\n");
assembly_stream_.Print(".setfp r11, sp, #0\n");
#endif
#endif
}
void AssemblyImageWriter::FrameUnwindEpilogue() {
#if defined(TARGET_ARCH_ARM)
#if !defined(TARGET_OS_MACOS) && !defined(TARGET_OS_MACOS_IOS)
assembly_stream_.Print(".fnend\n");
#endif
#endif
assembly_stream_.Print(".cfi_endproc\n");
}
intptr_t AssemblyImageWriter::WriteByteSequence(uword start, uword end) {
assert(end >= start);
auto const end_of_words =
Utils::RoundDown(end, sizeof(compiler::target::uword));
for (auto cursor = reinterpret_cast<compiler::target::uword*>(start);
cursor < reinterpret_cast<compiler::target::uword*>(end_of_words);
cursor++) {
WriteWordLiteralText(*cursor);
}
if (end != end_of_words) {
auto start_of_rest = reinterpret_cast<const uint8_t*>(end_of_words);
assembly_stream_.Print(".byte ");
for (auto cursor = start_of_rest;
cursor < reinterpret_cast<const uint8_t*>(end); cursor++) {
if (cursor != start_of_rest) assembly_stream_.Print(", ");
assembly_stream_.Print("0x%0.2" Px "", *cursor);
}
assembly_stream_.Print("\n");
}
return end - start;
}
intptr_t AssemblyImageWriter::Align(intptr_t alignment, uword position) {
const uword next_position = Utils::RoundUp(position, alignment);
assembly_stream_.Print(".balign %" Pd ", 0\n", alignment);
return next_position - position;
}
BlobImageWriter::BlobImageWriter(Thread* thread,
uint8_t** instructions_blob_buffer,
ReAlloc alloc,
intptr_t initial_size,
Elf* debug_elf,
Elf* elf)
: ImageWriter(thread),
instructions_blob_stream_(instructions_blob_buffer, alloc, initial_size),
elf_(elf),
debug_elf_(debug_elf) {
#if defined(DART_PRECOMPILER)
ASSERT(debug_elf_ == nullptr || debug_elf_->dwarf() != nullptr);
#else
RELEASE_ASSERT(elf_ == nullptr);
#endif
}
intptr_t BlobImageWriter::WriteByteSequence(uword start, uword end) {
const uword size = end - start;
instructions_blob_stream_.WriteBytes(reinterpret_cast<const void*>(start),
size);
return size;
}
void BlobImageWriter::WriteText(WriteStream* clustered_stream, bool vm) {
const bool bare_instruction_payloads =
FLAG_precompiled_mode && FLAG_use_bare_instructions;
auto const zone = Thread::Current()->zone();
#if defined(DART_PRECOMPILER)
auto const instructions_symbol = vm ? kVmSnapshotInstructionsAsmSymbol
: kIsolateSnapshotInstructionsAsmSymbol;
intptr_t segment_base = 0;
if (elf_ != nullptr) {
segment_base = elf_->NextMemoryOffset();
}
intptr_t debug_segment_base = 0;
if (debug_elf_ != nullptr) {
debug_segment_base = debug_elf_->NextMemoryOffset();
// If we're also generating an ELF snapshot, we want the virtual addresses
// in it and the separately saved DWARF information to match.
ASSERT(elf_ == nullptr || segment_base == debug_segment_base);
}
#endif
intptr_t text_offset = 0;
#if defined(DART_PRECOMPILER)
// Parent used for later profile objects. Starts off as the Image. When
// writing bare instructions payloads, this is later updated with the
// InstructionsSection object which contains all the bare payloads.
V8SnapshotProfileWriter::ObjectId parent_id(offset_space_, text_offset);
#endif
// This header provides the gap to make the instructions snapshot look like a
// OldPage.
const intptr_t image_size = Utils::RoundUp(
next_text_offset_, compiler::target::ObjectAlignment::kObjectAlignment);
instructions_blob_stream_.WriteTargetWord(image_size);
#if defined(DART_PRECOMPILER)
// Store the offset of the BSS section from the instructions section here.
// If not compiling to ELF (and thus no BSS segment), write 0.
const word bss_offset =
elf_ != nullptr ? elf_->BssStart(vm) - segment_base : 0;
ASSERT_EQUAL(Utils::RoundDown(bss_offset, Image::kBssAlignment), bss_offset);
// Set the lowest bit if we are compiling to ELF.
const word compiled_to_elf = elf_ != nullptr ? 0x1 : 0x0;
instructions_blob_stream_.WriteTargetWord(bss_offset | compiled_to_elf);
#else
instructions_blob_stream_.WriteTargetWord(0); // No relocations.
#endif
instructions_blob_stream_.Align(kMaxObjectAlignment);
ASSERT_EQUAL(instructions_blob_stream_.Position(), Image::kHeaderSize);
text_offset += Image::kHeaderSize;
#if defined(DART_PRECOMPILER)
if (profile_writer_ != nullptr) {
profile_writer_->SetObjectTypeAndName(parent_id, "Image",
instructions_symbol);
// Assign post-instruction padding to the Image, unless we're writing bare
// instruction payloads, in which case we'll assign it to the
// InstructionsSection object.
const intptr_t padding =
bare_instruction_payloads ? 0 : image_size - next_text_offset_;
profile_writer_->AttributeBytesTo(parent_id, Image::kHeaderSize + padding);
profile_writer_->AddRoot(parent_id);
}
#endif
if (bare_instruction_payloads) {
#if defined(DART_PRECOMPILER)
if (profile_writer_ != nullptr) {
const V8SnapshotProfileWriter::ObjectId id(offset_space_, text_offset);
profile_writer_->SetObjectTypeAndName(id, instructions_section_type_,
instructions_symbol);
const intptr_t padding = image_size - next_text_offset_;
profile_writer_->AttributeBytesTo(
id, compiler::target::InstructionsSection::HeaderSize() + padding);
const intptr_t element_offset = id.second - parent_id.second;
profile_writer_->AttributeReferenceTo(
parent_id,
{id, V8SnapshotProfileWriter::Reference::kElement, element_offset});
// Later objects will have the InstructionsSection as a parent.
parent_id = id;
}
#endif
const intptr_t section_size = image_size - Image::kHeaderSize;
// Add the RawInstructionsSection header.
const compiler::target::uword marked_tags =
ObjectLayout::OldBit::encode(true) |
ObjectLayout::OldAndNotMarkedBit::encode(false) |
ObjectLayout::OldAndNotRememberedBit::encode(true) |
ObjectLayout::NewBit::encode(false) |
ObjectLayout::SizeTag::encode(AdjustObjectSizeForTarget(section_size)) |
ObjectLayout::ClassIdTag::encode(kInstructionsSectionCid);
instructions_blob_stream_.WriteTargetWord(marked_tags);
// Uses next_text_offset_ to avoid any post-payload padding.
const intptr_t instructions_length =
next_text_offset_ - Image::kHeaderSize -
compiler::target::InstructionsSection::HeaderSize();
instructions_blob_stream_.WriteTargetWord(instructions_length);
ASSERT_EQUAL(instructions_blob_stream_.Position() - text_offset,
compiler::target::InstructionsSection::HeaderSize());
text_offset += compiler::target::InstructionsSection::HeaderSize();
}
ASSERT_EQUAL(text_offset, instructions_blob_stream_.Position());
#if defined(DART_PRECOMPILER)
auto& descriptors = PcDescriptors::Handle(zone);
#endif
SnapshotTextObjectNamer namer(zone);
NoSafepointScope no_safepoint;
for (intptr_t i = 0; i < instructions_.length(); i++) {
auto& data = instructions_[i];
const bool is_trampoline = data.trampoline_bytes != nullptr;
ASSERT(data.text_offset_ == text_offset);
#if defined(DART_PRECOMPILER)
const auto object_name = namer.SnapshotNameFor(i, data);
if (profile_writer_ != nullptr) {
const V8SnapshotProfileWriter::ObjectId id(offset_space_, text_offset);
auto const type = is_trampoline ? trampoline_type_ : instructions_type_;
const intptr_t size = is_trampoline ? data.trampoline_length
: SizeInSnapshot(data.insns_->raw());
profile_writer_->SetObjectTypeAndName(id, type, object_name);
profile_writer_->AttributeBytesTo(id, size);
// If the object is wrapped in an InstructionSection, then add an
// element reference.
const intptr_t element_offset = id.second - parent_id.second;
profile_writer_->AttributeReferenceTo(
parent_id,
{id, V8SnapshotProfileWriter::Reference::kElement, element_offset});
}
#endif
if (is_trampoline) {
const auto start = reinterpret_cast<uword>(data.trampoline_bytes);
const auto end = start + data.trampoline_length;
text_offset += WriteByteSequence(start, end);
delete[] data.trampoline_bytes;
data.trampoline_bytes = nullptr;
continue;
}
const intptr_t instr_start = text_offset;
const auto& insns = *data.insns_;
const uword payload_start = insns.PayloadStart();
ASSERT(Utils::IsAligned(payload_start, sizeof(compiler::target::uword)));
// Write Instructions with the mark and read-only bits set.
uword marked_tags = insns.raw_ptr()->tags_;
marked_tags = ObjectLayout::OldBit::update(true, marked_tags);
marked_tags = ObjectLayout::OldAndNotMarkedBit::update(false, marked_tags);
marked_tags =
ObjectLayout::OldAndNotRememberedBit::update(true, marked_tags);
marked_tags = ObjectLayout::NewBit::update(false, marked_tags);
#if defined(HASH_IN_OBJECT_HEADER)
// Can't use GetObjectTagsAndHash because the update methods discard the
// high bits.
marked_tags |= static_cast<uword>(insns.raw_ptr()->hash_) << 32;
#endif
#if defined(IS_SIMARM_X64)
const intptr_t start_offset = instructions_blob_stream_.bytes_written();
if (!bare_instruction_payloads) {
const intptr_t size_in_bytes = InstructionsSizeInSnapshot(insns.raw());
marked_tags = UpdateObjectSizeForTarget(size_in_bytes, marked_tags);
instructions_blob_stream_.WriteTargetWord(marked_tags);
instructions_blob_stream_.WriteFixed<uint32_t>(
insns.raw_ptr()->size_and_flags_);
} else {
ASSERT(Utils::IsAligned(instructions_blob_stream_.Position(),
kBareInstructionsAlignment));
}
const intptr_t payload_offset = instructions_blob_stream_.Position();
instructions_blob_stream_.WriteBytes(
reinterpret_cast<const void*>(insns.PayloadStart()), insns.Size());
const intptr_t alignment =
bare_instruction_payloads
? kBareInstructionsAlignment
: compiler::target::ObjectAlignment::kObjectAlignment;
instructions_blob_stream_.Align(alignment);
const intptr_t end_offset = instructions_blob_stream_.bytes_written();
text_offset += (end_offset - start_offset);
#else // defined(IS_SIMARM_X64)
// Only payload is output in AOT snapshots.
const uword header_size =
bare_instruction_payloads
? 0
: compiler::target::Instructions::HeaderSize();
const uword payload_size = SizeInSnapshot(insns.raw()) - header_size;
const uword object_end = payload_start + payload_size;
if (!bare_instruction_payloads) {
uword object_start = reinterpret_cast<uword>(insns.raw_ptr());
instructions_blob_stream_.WriteWord(marked_tags);
text_offset += sizeof(uword);
object_start += sizeof(uword);
text_offset += WriteByteSequence(object_start, payload_start);
} else {
ASSERT(Utils::IsAligned(instructions_blob_stream_.Position(),
kBareInstructionsAlignment));
}
const intptr_t payload_offset = instructions_blob_stream_.Position();
text_offset += WriteByteSequence(payload_start, object_end);
#endif
#if defined(DART_PRECOMPILER)
const auto& code = *data.code_;
if (elf_ != nullptr && elf_->dwarf() != nullptr) {
elf_->dwarf()->AddCode(code, {vm, payload_offset});
}
if (debug_elf_ != nullptr) {
debug_elf_->dwarf()->AddCode(code, {vm, payload_offset});
}
// Don't patch the relocation if we're not generating ELF. The regular blobs
// format does not yet support these relocations. Use
// Code::VerifyBSSRelocations to check whether the relocations are patched
// or not after loading.
if (elf_ != nullptr) {
const intptr_t current_stream_position =
instructions_blob_stream_.Position();
descriptors = code.pc_descriptors();
PcDescriptors::Iterator iterator(
descriptors, /*kind_mask=*/PcDescriptorsLayout::kBSSRelocation);
while (iterator.MoveNext()) {
const intptr_t reloc_offset = iterator.PcOffset();
// The instruction stream at the relocation position holds an offset
// into BSS corresponding to the symbol being resolved. This addend is
// factored into the relocation.
const auto addend = *reinterpret_cast<compiler::target::word*>(
insns.PayloadStart() + reloc_offset);
// Overwrite the relocation position in the instruction stream with the
// offset of the BSS segment from the relocation position plus the
// addend in the relocation.
auto const reloc_pos = payload_offset + reloc_offset;
instructions_blob_stream_.SetPosition(reloc_pos);
const compiler::target::word offset = bss_offset - reloc_pos + addend;
instructions_blob_stream_.WriteTargetWord(offset);
}
// Restore stream position after the relocation was patched.
instructions_blob_stream_.SetPosition(current_stream_position);
}
#else
USE(payload_offset);
#endif
ASSERT((text_offset - instr_start) ==
ImageWriter::SizeInSnapshot(insns.raw()));
}
// Should be a no-op unless writing bare instruction payloads, in which case
// we need to add post-payload padding to the object alignment. The alignment
// should match the alignment used in image_size above.
instructions_blob_stream_.Align(
compiler::target::ObjectAlignment::kObjectAlignment);
text_offset = Utils::RoundUp(
text_offset, compiler::target::ObjectAlignment::kObjectAlignment);
ASSERT_EQUAL(text_offset, instructions_blob_stream_.bytes_written());
ASSERT_EQUAL(text_offset, image_size);
#ifdef DART_PRECOMPILER
auto const data_symbol =
vm ? kVmSnapshotDataAsmSymbol : kIsolateSnapshotDataAsmSymbol;
if (elf_ != nullptr) {
auto const segment_base2 =
elf_->AddText(instructions_symbol, instructions_blob_stream_.buffer(),
instructions_blob_stream_.bytes_written());
ASSERT_EQUAL(segment_base2, segment_base);
// Write the .rodata section here like the AssemblyImageWriter.
elf_->AddROData(data_symbol, clustered_stream->buffer(),
clustered_stream->bytes_written());
}
if (debug_elf_ != nullptr) {
// To keep memory addresses consistent, we create elf::SHT_NOBITS sections
// in the debugging information. We still pass along the buffers because
// we'll need the buffer bytes at generation time to calculate the build ID
// so it'll match the one in the snapshot.
auto const debug_segment_base2 = debug_elf_->AddText(
instructions_symbol, instructions_blob_stream_.buffer(),
instructions_blob_stream_.bytes_written());
ASSERT_EQUAL(debug_segment_base2, debug_segment_base);
debug_elf_->AddROData(data_symbol, clustered_stream->buffer(),
clustered_stream->bytes_written());
}
#endif
}
#endif // !defined(DART_PRECOMPILED_RUNTIME)
ImageReader::ImageReader(const uint8_t* data_image,
const uint8_t* instructions_image)
: data_image_(data_image), instructions_image_(instructions_image) {
ASSERT(data_image != NULL);
ASSERT(instructions_image != NULL);
}
ApiErrorPtr ImageReader::VerifyAlignment() const {
if (!Utils::IsAligned(data_image_, kObjectAlignment) ||
!Utils::IsAligned(instructions_image_, kMaxObjectAlignment)) {
return ApiError::New(
String::Handle(String::New("Snapshot is misaligned", Heap::kOld)),
Heap::kOld);
}
return ApiError::null();
}
#if defined(DART_PRECOMPILED_RUNTIME)
uword ImageReader::GetBareInstructionsAt(uint32_t offset) const {
ASSERT(Utils::IsAligned(offset, ImageWriter::kBareInstructionsAlignment));
return reinterpret_cast<uword>(instructions_image_) + offset;
}
uword ImageReader::GetBareInstructionsEnd() const {
Image image(instructions_image_);
return reinterpret_cast<uword>(image.object_start()) + image.object_size();
}
#endif
InstructionsPtr ImageReader::GetInstructionsAt(uint32_t offset) const {
ASSERT(Utils::IsAligned(offset, kObjectAlignment));
ObjectPtr result = ObjectLayout::FromAddr(
reinterpret_cast<uword>(instructions_image_) + offset);
ASSERT(result->IsInstructions());
ASSERT(result->ptr()->IsMarked());
return Instructions::RawCast(result);
}
ObjectPtr ImageReader::GetObjectAt(uint32_t offset) const {
ASSERT(Utils::IsAligned(offset, kObjectAlignment));
ObjectPtr result =
ObjectLayout::FromAddr(reinterpret_cast<uword>(data_image_) + offset);
ASSERT(result->ptr()->IsMarked());
return result;
}
} // namespace dart