blob: b1694592403af40576498fa51662d6cec62d2aec [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.
#ifndef RUNTIME_VM_IMAGE_SNAPSHOT_H_
#define RUNTIME_VM_IMAGE_SNAPSHOT_H_
#include <memory>
#include <utility>
#include "platform/assert.h"
#include "platform/utils.h"
#include "vm/allocation.h"
#include "vm/compiler/runtime_api.h"
#include "vm/datastream.h"
#include "vm/elf.h"
#include "vm/globals.h"
#include "vm/growable_array.h"
#include "vm/hash_map.h"
#include "vm/object.h"
#include "vm/reusable_handles.h"
#include "vm/type_testing_stubs.h"
#include "vm/v8_snapshot_writer.h"
#if defined(DEBUG)
#define SNAPSHOT_BACKTRACE
#endif
namespace dart {
// Forward declarations.
class BitsContainer;
class Code;
class Dwarf;
class Elf;
class Instructions;
class Object;
class Image : ValueObject {
public:
explicit Image(const void* raw_memory)
: Image(reinterpret_cast<uword>(raw_memory)) {}
explicit Image(const uword raw_memory)
: raw_memory_(raw_memory),
snapshot_size_(FieldValue(raw_memory, HeaderField::ImageSize)),
extra_info_(ExtraInfo(raw_memory_, snapshot_size_)) {
ASSERT(Utils::IsAligned(raw_memory, kObjectStartAlignment));
}
// Even though an Image is read-only memory, we must return a void* here.
// All objects in an Image are pre-marked, though, so the GC will not attempt
// to change the returned memory.
void* object_start() const {
return reinterpret_cast<void*>(raw_memory_ + kHeaderSize);
}
uword object_size() const { return snapshot_size_ - kHeaderSize; }
bool contains(uword address) const {
uword start = reinterpret_cast<uword>(object_start());
return address >= start && (address - start < object_size());
}
// Returns the address of the BSS section, or nullptr if one is not available.
// Only has meaning for instructions images from precompiled snapshots.
uword* bss() const;
// Returns the relocated address of the isolate's instructions, or 0 if
// one is not available. Only has meaning for instructions images from
// precompiled snapshots.
uword instructions_relocated_address() const;
// Returns the GNU build ID, or nullptr if not available. See
// build_id_length() for the length of the returned buffer. Only has meaning
// for instructions images from precompiled snapshots.
const uint8_t* build_id() const;
// Returns the length of the GNU build ID returned by build_id(). Only has
// meaning for instructions images from precompiled snapshots.
intptr_t build_id_length() const;
// Returns whether this instructions section was compiled to ELF. Only has
// meaning for instructions images from precompiled snapshots.
bool compiled_to_elf() const;
private:
// Word-sized fields in an Image object header.
enum class HeaderField : intptr_t {
// The size of the image (total of header and payload).
ImageSize,
// The offset of the InstructionsSection object in the image. Note this
// offset is from the start of the _image_, _not_ from its payload start,
// so we can detect images without an InstructionsSection by a 0 value here.
InstructionsSectionOffset,
// If adding more fields, updating kHeaderFields below. (However, more
// fields _can't_ be added on 64-bit architectures, see the restrictions
// on kHeaderSize below.)
};
// Number of fields described by the HeaderField enum.
static constexpr intptr_t kHeaderFields =
static_cast<intptr_t>(HeaderField::InstructionsSectionOffset) + 1;
static uword FieldValue(uword raw_memory, HeaderField field) {
return reinterpret_cast<const uword*>(
raw_memory)[static_cast<intptr_t>(field)];
}
// Constants used to denote special values for the offsets in the Image
// object header and the fields of the InstructionsSection object.
static constexpr intptr_t kNoInstructionsSection = 0;
static constexpr intptr_t kNoBssSection = 0;
static constexpr intptr_t kNoRelocatedAddress = 0;
static constexpr intptr_t kNoBuildId = 0;
// The size of the Image object header.
//
// Note: Image::kHeaderSize is _not_ an architecture-dependent constant,
// and so there is no compiler::target::Image::kHeaderSize.
static constexpr intptr_t kHeaderSize = kObjectStartAlignment;
// Explicitly double-checking kHeaderSize is never changed. Increasing the
// Image header size would mean objects would not start at a place expected
// by parts of the VM (like the GC) that use Image pages as Pages.
static_assert(kHeaderSize == kObjectStartAlignment,
"Image page cannot be used as Page");
// Make sure that the number of fields in the Image header fit both on the
// host and target architectures.
static_assert(kHeaderFields * kWordSize <= kHeaderSize,
"Too many fields in Image header for host architecture");
static_assert(kHeaderFields * compiler::target::kWordSize <= kHeaderSize,
"Too many fields in Image header for target architecture");
// We don't use a handle or the tagged pointer because this object cannot be
// moved in memory by the GC.
static const UntaggedInstructionsSection* ExtraInfo(const uword raw_memory,
const uword size);
// Most internal uses would cast this to uword, so just store it as such.
const uword raw_memory_;
const intptr_t snapshot_size_;
const UntaggedInstructionsSection* const extra_info_;
// For access to private constants.
friend class AssemblyImageWriter;
friend class BitsContainer;
friend class BlobImageWriter;
friend class ImageWriter;
DISALLOW_COPY_AND_ASSIGN(Image);
};
class ImageReader : public ZoneAllocated {
public:
ImageReader(const uint8_t* data_image, const uint8_t* instructions_image);
ApiErrorPtr VerifyAlignment() const;
ONLY_IN_PRECOMPILED(uword GetBareInstructionsAt(uint32_t offset) const);
ONLY_IN_PRECOMPILED(uword GetBareInstructionsEnd() const);
InstructionsPtr GetInstructionsAt(uint32_t offset) const;
ObjectPtr GetObjectAt(uint32_t offset) const;
private:
const uint8_t* data_image_;
const uint8_t* instructions_image_;
DISALLOW_COPY_AND_ASSIGN(ImageReader);
};
struct ObjectOffsetPair {
public:
ObjectOffsetPair() : ObjectOffsetPair(nullptr, 0) {}
ObjectOffsetPair(ObjectPtr obj, int32_t off) : object(obj), offset(off) {}
ObjectPtr object;
int32_t offset;
};
class ObjectOffsetTrait {
public:
// Typedefs needed for the DirectChainedHashMap template.
typedef ObjectPtr Key;
typedef int32_t Value;
typedef ObjectOffsetPair Pair;
static Key KeyOf(Pair kv) { return kv.object; }
static Value ValueOf(Pair kv) { return kv.offset; }
static uword Hash(Key key);
static inline bool IsKeyEqual(Pair pair, Key key);
};
typedef DirectChainedHashMap<ObjectOffsetTrait> ObjectOffsetMap;
// A command which instructs the image writer to emit something into the ".text"
// segment.
//
// For now this supports
//
// * emitting the instructions of a [Code] object
// * emitting a trampoline of a certain size
// * emitting a padding of a certain size
//
struct ImageWriterCommand {
enum Opcode {
InsertInstructionOfCode,
InsertBytesOfTrampoline,
InsertPadding,
};
ImageWriterCommand(intptr_t expected_offset, CodePtr code)
: expected_offset(expected_offset),
op(ImageWriterCommand::InsertInstructionOfCode),
insert_instruction_of_code({code}) {}
ImageWriterCommand(intptr_t expected_offset,
uint8_t* trampoline_bytes,
intptr_t trampoline_length)
: expected_offset(expected_offset),
op(ImageWriterCommand::InsertBytesOfTrampoline),
insert_trampoline_bytes({trampoline_bytes, trampoline_length}) {}
ImageWriterCommand(intptr_t expected_offset, intptr_t padding_length)
: expected_offset(expected_offset),
op(ImageWriterCommand::InsertPadding),
insert_padding({padding_length}) {}
// The offset (relative to the very first [ImageWriterCommand]) we expect
// this [ImageWriterCommand] to have.
intptr_t expected_offset;
Opcode op;
union {
struct {
CodePtr code;
} insert_instruction_of_code;
struct {
uint8_t* buffer;
intptr_t buffer_length;
} insert_trampoline_bytes;
struct {
intptr_t padding_length;
} insert_padding;
};
};
#if defined(DART_PRECOMPILER)
template <typename T>
class Trie : public ZoneAllocated {
public:
// Returns whether [key] is a valid trie key (that is, a C string that
// contains only characters for which charIndex returns a non-negative value).
static bool IsValidKey(const char* key) {
for (intptr_t i = 0; key[i] != '\0'; i++) {
if (ChildIndex(key[i]) < 0) return false;
}
return true;
}
// Adds a binding of [key] to [value] in [trie]. Assumes that the string in
// [key] is a valid trie key and does not already have a value in [trie].
//
// If [trie] is nullptr, then a new trie is created and a pointer to the new
// trie is returned. Otherwise, [trie] will be returned.
static Trie<T>* AddString(Zone* zone,
Trie<T>* trie,
const char* key,
const T* value);
// Adds a binding of [key] to [value]. Assumes that the string in [key] is a
// valid trie key and does not already have a value in this trie.
void AddString(Zone* zone, const char* key, const T* value) {
AddString(zone, this, key, value);
}
// Looks up the value stored for [key] in [trie]. If one is not found, then
// nullptr is returned.
//
// If [end] is not nullptr, then the longest prefix of [key] that is a valid
// trie key prefix will be used for the lookup and the value pointed to by
// [end] is set to the index after that prefix. Otherwise, the whole [key]
// is used.
static const T* Lookup(const Trie<T>* trie,
const char* key,
intptr_t* end = nullptr);
// Looks up the value stored for [key]. If one is not found, then nullptr is
// returned.
//
// If [end] is not nullptr, then the longest prefix of [key] that is a valid
// trie key prefix will be used for the lookup and the value pointed to by
// [end] is set to the index after that prefix. Otherwise, the whole [key]
// is used.
const T* Lookup(const char* key, intptr_t* end = nullptr) const {
return Lookup(this, key, end);
}
private:
// Currently, only the following characters can appear in obfuscated names:
// '_', '@', '0-9', 'a-z', 'A-Z'
static constexpr intptr_t kNumValidChars = 64;
Trie() {
for (intptr_t i = 0; i < kNumValidChars; i++) {
children_[i] = nullptr;
}
}
static intptr_t ChildIndex(char c) {
if (c == '_') return 0;
if (c == '@') return 1;
if (c >= '0' && c <= '9') return ('9' - c) + 2;
if (c >= 'a' && c <= 'z') return ('z' - c) + 12;
if (c >= 'A' && c <= 'Z') return ('Z' - c) + 38;
return -1;
}
const T* value_ = nullptr;
Trie<T>* children_[kNumValidChars];
};
template <typename T>
Trie<T>* Trie<T>::AddString(Zone* zone,
Trie<T>* trie,
const char* key,
const T* value) {
ASSERT(key != nullptr);
if (trie == nullptr) {
trie = new (zone) Trie<T>();
}
if (*key == '\0') {
ASSERT(trie->value_ == nullptr);
trie->value_ = value;
} else {
auto const index = ChildIndex(*key);
ASSERT(index >= 0 && index < kNumValidChars);
trie->children_[index] =
AddString(zone, trie->children_[index], key + 1, value);
}
return trie;
}
template <typename T>
const T* Trie<T>::Lookup(const Trie<T>* trie, const char* key, intptr_t* end) {
intptr_t i = 0;
for (; key[i] != '\0'; i++) {
auto const index = ChildIndex(key[i]);
ASSERT(index < kNumValidChars);
if (index < 0) {
if (end == nullptr) return nullptr;
break;
}
// Still find the longest valid trie prefix when no stored value.
if (trie == nullptr) continue;
trie = trie->children_[index];
}
if (end != nullptr) {
*end = i;
}
if (trie == nullptr) return nullptr;
return trie->value_;
}
#endif
class ImageWriter : public ValueObject {
public:
#if defined(DART_PRECOMPILER)
ImageWriter(Thread* thread,
bool generates_assembly,
const Trie<const char>* deobfuscation_trie = nullptr);
#else
ImageWriter(Thread* thread, bool generates_assembly);
#endif
virtual ~ImageWriter() {}
// Alignment constants used in writing ELF or assembly snapshots.
// BSS sections contain word-sized data.
static constexpr intptr_t kBssAlignment = compiler::target::kWordSize;
// ROData sections contain objects wrapped in an Image object.
static constexpr intptr_t kRODataAlignment = kObjectStartAlignment;
// Text sections contain objects (even in bare instructions mode) wrapped
// in an Image object.
static constexpr intptr_t kTextAlignment = kObjectStartAlignment;
void ResetOffsets() {
next_data_offset_ = Image::kHeaderSize;
next_text_offset_ = Image::kHeaderSize;
#if defined(DART_PRECOMPILER)
if (FLAG_precompiled_mode) {
// We reserve space for the initial InstructionsSection object. It is
// manually serialized since it includes offsets to other snapshot parts.
// It contains all the payloads which start directly after the header.
next_text_offset_ += compiler::target::InstructionsSection::HeaderSize();
}
#endif
objects_.Clear();
instructions_.Clear();
}
// Will start preparing the ".text" segment by interpreting the provided
// [ImageWriterCommand]s.
void PrepareForSerialization(GrowableArray<ImageWriterCommand>* commands);
bool IsROSpace() const {
return offset_space_ == IdSpace::kVmData ||
offset_space_ == IdSpace::kVmText ||
offset_space_ == IdSpace::kIsolateData ||
offset_space_ == IdSpace::kIsolateText;
}
int32_t GetTextOffsetFor(InstructionsPtr instructions, CodePtr code);
#if defined(SNAPSHOT_BACKTRACE)
uint32_t GetDataOffsetFor(ObjectPtr raw_object, ObjectPtr raw_parent);
#else
uint32_t GetDataOffsetFor(ObjectPtr raw_object);
#endif
uint32_t AddBytesToData(uint8_t* bytes, intptr_t length);
void Write(NonStreamingWriteStream* clustered_stream, bool vm);
intptr_t data_size() const { return next_data_offset_; }
intptr_t text_size() const { return next_text_offset_; }
intptr_t GetTextObjectCount() const;
void GetTrampolineInfo(intptr_t* count, intptr_t* size) const;
void DumpStatistics();
void SetProfileWriter(V8SnapshotProfileWriter* profile_writer) {
profile_writer_ = profile_writer;
}
void ClearProfileWriter() { profile_writer_ = nullptr; }
void TraceInstructions(const Instructions& instructions);
static intptr_t SizeInSnapshot(ObjectPtr object);
static intptr_t SizeInSnapshot(const Object& object) {
return SizeInSnapshot(object.ptr());
}
// Returns nullptr if there is no profile writer.
const char* ObjectTypeForProfile(const Object& object) const;
static const char* TagObjectTypeAsReadOnly(Zone* zone, const char* type);
enum class ProgramSection {
Text, // Instructions.
Data, // Read-only data.
Bss, // Statically allocated variables initialized at load.
BuildId, // GNU build ID (when applicable)
// Adjust kNumProgramSections below to use last enum value added.
};
static constexpr intptr_t kNumProgramSections =
static_cast<int>(ProgramSection::BuildId) + 1;
#if defined(DART_PRECOMPILER)
// Returns a predetermined label for the given section in the VM isolate
// (if vm is true) or application isolate (otherwise) section. Some sections
// are shared by both.
static constexpr intptr_t SectionLabel(ProgramSection section, bool vm) {
// Both vm and isolate share the build id section.
const bool shared = section == ProgramSection::BuildId;
// The initial 1 is to ensure the result is positive.
return 1 + 2 * static_cast<int>(section) + ((shared || vm) ? 0 : 1);
}
static Trie<const char>* CreateReverseObfuscationTrie(Thread* thread);
static const char* Deobfuscate(Zone* zone,
const Trie<const char>* trie,
const char* str);
#endif
protected:
virtual void WriteBss(bool vm) = 0;
virtual void WriteROData(NonStreamingWriteStream* clustered_stream, bool vm);
void WriteText(bool vm);
// Returns the standard Dart dynamic symbol name for the given VM isolate (if
// vm is true) or application isolate (otherwise) section. Some sections are
// shared by both.
static const char* SectionSymbol(ProgramSection section, bool vm);
static uword GetMarkedTags(classid_t cid,
intptr_t size,
bool is_canonical = false);
static uword GetMarkedTags(const Object& obj);
void DumpInstructionStats();
void DumpInstructionsSizes();
struct InstructionsData {
InstructionsData(InstructionsPtr insns, CodePtr code, intptr_t text_offset)
: raw_insns_(insns),
raw_code_(code),
text_offset_(text_offset),
trampoline_bytes(nullptr),
trampoline_length(0) {}
InstructionsData(uint8_t* trampoline_bytes,
intptr_t trampoline_length,
intptr_t text_offset)
: raw_insns_(nullptr),
raw_code_(nullptr),
text_offset_(text_offset),
trampoline_bytes(trampoline_bytes),
trampoline_length(trampoline_length) {}
union {
InstructionsPtr raw_insns_;
const Instructions* insns_;
};
union {
CodePtr raw_code_;
const Code* code_;
};
intptr_t text_offset_;
uint8_t* trampoline_bytes;
intptr_t trampoline_length;
};
struct ObjectData {
#if defined(SNAPSHOT_BACKTRACE)
explicit ObjectData(ObjectPtr raw_obj, ObjectPtr raw_parent)
: raw_obj(raw_obj),
raw_parent(raw_parent),
flags(IsObjectField::encode(true) |
IsOriginalObjectField::encode(true)) {}
ObjectData(uint8_t* buf, intptr_t length)
: bytes({buf, length}),
raw_parent(Object::null()),
flags(IsObjectField::encode(false) |
IsOriginalObjectField::encode(false)) {}
#else
explicit ObjectData(ObjectPtr raw_obj)
: raw_obj(raw_obj),
flags(IsObjectField::encode(true) |
IsOriginalObjectField::encode(true)) {}
ObjectData(uint8_t* buf, intptr_t length)
: bytes({buf, length}),
flags(IsObjectField::encode(false) |
IsOriginalObjectField::encode(false)) {}
#endif
union {
struct {
uint8_t* buf;
intptr_t length;
} bytes;
ObjectPtr raw_obj;
const Object* obj;
};
#if defined(SNAPSHOT_BACKTRACE)
union {
ObjectPtr raw_parent;
const Object* parent;
};
#endif
uint8_t flags;
bool is_object() const { return IsObjectField::decode(flags); }
bool is_original_object() const {
return IsOriginalObjectField::decode(flags);
}
void set_is_object(bool value) {
flags = IsObjectField::update(value, flags);
}
using IsObjectField = BitField<uint8_t, bool, 0, 1>;
using IsOriginalObjectField =
BitField<uint8_t, bool, IsObjectField::kNextBit, 1>;
};
// Methods abstracting out the particulars of the underlying concrete writer.
// Marks the entrance into a particular ProgramSection for either the VM
// isolate (if vm is true) or application isolate (if not). Returns false if
// this section should not be written.
virtual bool EnterSection(ProgramSection name,
bool vm,
intptr_t alignment,
intptr_t* alignment_padding = nullptr) = 0;
// Marks the exit from a particular ProgramSection, allowing subclasses to
// do any post-writing work.
virtual void ExitSection(ProgramSection name, bool vm, intptr_t size) = 0;
// Writes a prologue to the text section that describes how to interpret
// Dart stack frames using DWARF's Call Frame Information (CFI).
virtual void FrameUnwindPrologue() = 0;
// Writes an epilogue to the text section that marks the end of instructions
// covered by the CFI information in the prologue.
virtual void FrameUnwindEpilogue() = 0;
// Writes a target uword-sized value to the section contents.
virtual intptr_t WriteTargetWord(word value) = 0;
// Writes a sequence of bytes of length [size] from address [bytes] to the
// section contents.
virtual intptr_t WriteBytes(const void* bytes, intptr_t size) = 0;
// Pads the section contents to a given alignment with zeroes.
virtual intptr_t Align(intptr_t alignment,
intptr_t offset,
intptr_t position) = 0;
#if defined(DART_PRECOMPILER)
// Writes a target word-sized value that depends on the final relocated
// addresses of the sections named by the two symbols. If T is the final
// relocated address of the target section and S is the final relocated
// address of the source, the final value is:
// (T + target_offset + target_addend) - (S + source_offset)
virtual intptr_t Relocation(intptr_t section_offset,
intptr_t source_label,
intptr_t source_offset,
intptr_t target_label,
intptr_t target_offset) = 0;
// Writes a target word-sized value that contains the relocated address
// pointed to by the given symbol.
virtual intptr_t RelocatedAddress(intptr_t section_offset,
intptr_t label) = 0;
// Creates a static symbol for the given Code object when appropriate.
virtual void AddCodeSymbol(const Code& code,
const char* symbol,
intptr_t section_offset) = 0;
// Creates a static symbol for a read-only data object when appropriate.
virtual void AddDataSymbol(const char* symbol,
intptr_t section_offset,
size_t size) = 0;
// Overloaded convenience versions of the above virtual methods.
// An overload of Relocation where the target and source offsets and
// target addend are 0.
intptr_t Relocation(intptr_t section_offset,
intptr_t source_label,
intptr_t target_label) {
return Relocation(section_offset, source_label, 0, target_label, 0);
}
#endif
// Writes a fixed-sized value of type T to the section contents.
template <typename T>
intptr_t WriteFixed(T value) {
return WriteBytes(&value, sizeof(value));
}
// Like Align, but instead of padding with zeroes, the appropriate break
// instruction for the target architecture is used.
intptr_t AlignWithBreakInstructions(intptr_t alignment, intptr_t offset);
Thread* const thread_;
Zone* const zone_;
intptr_t next_data_offset_;
intptr_t next_text_offset_;
GrowableArray<ObjectData> objects_;
GrowableArray<InstructionsData> instructions_;
#if defined(DART_PRECOMPILER)
class SnapshotTextObjectNamer : ValueObject {
public:
explicit SnapshotTextObjectNamer(Zone* zone,
const Trie<const char>* deobfuscation_trie,
bool for_assembly)
: zone_(ASSERT_NOTNULL(zone)),
deobfuscation_trie_(deobfuscation_trie),
lib_(Library::Handle(zone)),
cls_(Class::Handle(zone)),
parent_(Function::Handle(zone)),
owner_(Object::Handle(zone)),
string_(String::Handle(zone)),
insns_(Instructions::Handle(zone)),
store_(IsolateGroup::Current()->object_store()),
for_assembly_(for_assembly),
usage_count_(zone) {}
const char* StubNameForType(const AbstractType& type) const;
// Returns a unique name for text data to use in symbols. The name is
// not assembly-safe and must be appropriately quoted in assembly output.
// Assumes that code in the InstructionsData has been allocated a handle.
const char* SnapshotNameFor(const InstructionsData& data);
// Returns a unique name for read-only data to use in symbols. The name is
// not assembly-safe and must be appropriately quoted in assembly output.
// Assumes that the ObjectData has already been converted to object handles.
const char* SnapshotNameFor(const ObjectData& data);
private:
// Returns a unique name for the given code or read-only data object for use
// in symbols. The name is not assembly-safe and must be appropriately
// quoted in assembly output.
const char* SnapshotNameFor(const Object& object);
// Adds a non-unique name for the given object to the given buffer.
void AddNonUniqueNameFor(BaseTextBuffer* buffer, const Object& object);
// Modifies the symbol name in the buffer as needed for assembly use.
void ModifyForAssembly(BaseTextBuffer* buffer);
Zone* const zone_;
const Trie<const char>* const deobfuscation_trie_;
Library& lib_;
Class& cls_;
Function& parent_;
Object& owner_;
String& string_;
Instructions& insns_;
ObjectStore* const store_;
// Used to decide whether we need to add a uniqueness suffix.
bool for_assembly_;
CStringIntMap usage_count_;
DISALLOW_COPY_AND_ASSIGN(SnapshotTextObjectNamer);
};
SnapshotTextObjectNamer namer_;
// Reserve two positive labels for each of the ProgramSection values (one for
// vm, one for isolate).
intptr_t next_label_ = 1 + 2 * kNumProgramSections;
#endif
IdSpace offset_space_ = IdSpace::kSnapshot;
V8SnapshotProfileWriter* profile_writer_ = nullptr;
const char* const image_type_;
const char* const instructions_section_type_;
const char* const instructions_type_;
const char* const trampoline_type_;
const char* const padding_type_;
template <class T>
friend class TraceImageObjectScope;
private:
static intptr_t SizeInSnapshotForBytes(intptr_t length);
DISALLOW_COPY_AND_ASSIGN(ImageWriter);
};
#if defined(DART_PRECOMPILER)
static_assert(ImageWriter::SectionLabel(ImageWriter::ProgramSection::Bss,
/*vm=*/true) == Elf::kVmBssLabel,
"unexpected label for VM BSS section");
static_assert(ImageWriter::SectionLabel(ImageWriter::ProgramSection::Bss,
/*vm=*/false) == Elf::kIsolateBssLabel,
"unexpected label for isolate BSS section");
static_assert(ImageWriter::SectionLabel(ImageWriter::ProgramSection::BuildId,
/*vm=*/true) == Elf::kBuildIdLabel,
"unexpected label for build id section");
static_assert(ImageWriter::SectionLabel(ImageWriter::ProgramSection::BuildId,
/*vm=*/false) == Elf::kBuildIdLabel,
"unexpected label for build id section");
#define AutoTraceImage(object, section_offset, stream) \
TraceImageObjectScope<std::remove_pointer<decltype(stream)>::type> \
AutoTraceImageObjectScopeVar##__COUNTER__(this, section_offset, stream, \
object);
template <typename T>
class TraceImageObjectScope : ValueObject {
public:
TraceImageObjectScope(ImageWriter* writer,
intptr_t section_offset,
const T* stream,
const Object& object)
: writer_(ASSERT_NOTNULL(writer)),
stream_(ASSERT_NOTNULL(stream)),
section_offset_(section_offset),
start_offset_(stream_->Position() - section_offset),
object_type_(writer->ObjectTypeForProfile(object)),
object_name_(object.IsString() ? object.ToCString() : nullptr) {}
~TraceImageObjectScope() {
if (writer_->profile_writer_ == nullptr) return;
ASSERT(writer_->IsROSpace());
writer_->profile_writer_->SetObjectTypeAndName(
{writer_->offset_space_, start_offset_}, object_type_, object_name_);
writer_->profile_writer_->AttributeBytesTo(
{writer_->offset_space_, start_offset_},
stream_->Position() - section_offset_ - start_offset_);
}
private:
ImageWriter* const writer_;
const T* const stream_;
const intptr_t section_offset_;
const intptr_t start_offset_;
const char* const object_type_;
const char* const object_name_;
DISALLOW_COPY_AND_ASSIGN(TraceImageObjectScope);
};
class AssemblyImageWriter : public ImageWriter {
public:
AssemblyImageWriter(Thread* thread,
BaseWriteStream* stream,
const Trie<const char>* deobfuscation_trie = nullptr,
bool strip = false,
Elf* debug_elf = nullptr);
void Finalize();
private:
virtual void WriteBss(bool vm);
virtual void WriteROData(NonStreamingWriteStream* clustered_stream, bool vm);
virtual bool EnterSection(ProgramSection section,
bool vm,
intptr_t alignment,
intptr_t* alignment_padding = nullptr);
virtual void ExitSection(ProgramSection name, bool vm, intptr_t size);
virtual intptr_t WriteTargetWord(word value);
virtual intptr_t WriteBytes(const void* bytes, intptr_t size);
virtual intptr_t Align(intptr_t alignment,
intptr_t offset,
intptr_t position);
virtual intptr_t Relocation(intptr_t section_offset,
intptr_t source_label,
intptr_t source_offset,
intptr_t target_label,
intptr_t target_offset);
virtual intptr_t RelocatedAddress(intptr_t section_offset, intptr_t label) {
// Cannot calculate snapshot-relative addresses in assembly snapshots.
return WriteTargetWord(Image::kNoRelocatedAddress);
}
virtual void FrameUnwindPrologue();
virtual void FrameUnwindEpilogue();
virtual void AddCodeSymbol(const Code& code,
const char* symbol,
intptr_t offset);
virtual void AddDataSymbol(const char* symbol, intptr_t offset, size_t size);
BaseWriteStream* const assembly_stream_;
Dwarf* const assembly_dwarf_;
Elf* const debug_elf_;
// Used in Relocation to output "(.)" for relocations involving the current
// section position.
intptr_t current_section_label_ = 0;
// Used for creating local symbols for code and data objects in the
// debugging info, if separately written.
ZoneGrowableArray<Elf::SymbolData>* current_symbols_ = nullptr;
// Maps labels to the appropriate symbol names for relocations and DWARF
// output.
IntMap<const char*> label_to_symbol_name_;
DISALLOW_COPY_AND_ASSIGN(AssemblyImageWriter);
};
#endif
class BlobImageWriter : public ImageWriter {
public:
#if defined(DART_PRECOMPILER)
BlobImageWriter(Thread* thread,
NonStreamingWriteStream* vm_instructions,
NonStreamingWriteStream* isolate_instructions,
const Trie<const char>* deobfuscation_trie = nullptr,
Elf* debug_elf = nullptr,
Elf* elf = nullptr);
#else
BlobImageWriter(Thread* thread,
NonStreamingWriteStream* vm_instructions,
NonStreamingWriteStream* isolate_instructions,
Elf* debug_elf = nullptr,
Elf* elf = nullptr);
#endif
private:
virtual void WriteBss(bool vm);
virtual void WriteROData(NonStreamingWriteStream* clustered_stream, bool vm);
virtual bool EnterSection(ProgramSection section,
bool vm,
intptr_t alignment,
intptr_t* alignment_padding = nullptr);
virtual void ExitSection(ProgramSection name, bool vm, intptr_t size);
virtual intptr_t WriteTargetWord(word value);
virtual intptr_t WriteBytes(const void* bytes, intptr_t size);
virtual intptr_t Align(intptr_t alignment,
intptr_t offset,
intptr_t position);
// TODO(rmacnak): Generate .debug_frame / .eh_frame / .arm.exidx to
// provide unwinding information.
virtual void FrameUnwindPrologue() {}
virtual void FrameUnwindEpilogue() {}
#if defined(DART_PRECOMPILER)
virtual intptr_t Relocation(intptr_t section_offset,
intptr_t source_label,
intptr_t source_offset,
intptr_t target_label,
intptr_t target_offset);
virtual intptr_t RelocatedAddress(intptr_t section_offset, intptr_t label) {
return ImageWriter::Relocation(section_offset,
Elf::Relocation::kSnapshotRelative, label);
}
virtual void AddCodeSymbol(const Code& code,
const char* symbol,
intptr_t offset);
virtual void AddDataSymbol(const char* symbol, intptr_t offset, size_t size);
// Set on section entrance to a new array containing the relocations for the
// current section.
ZoneGrowableArray<Elf::Relocation>* current_relocations_ = nullptr;
// Set on section entrance to a new array containing the local symbol data
// for the current section.
ZoneGrowableArray<Elf::SymbolData>* current_symbols_ = nullptr;
#endif
NonStreamingWriteStream* const vm_instructions_;
NonStreamingWriteStream* const isolate_instructions_;
Elf* const elf_;
Elf* const debug_elf_;
// Set on section entrance to the stream that should be used by the writing
// methods.
NonStreamingWriteStream* current_section_stream_ = nullptr;
DISALLOW_COPY_AND_ASSIGN(BlobImageWriter);
};
} // namespace dart
#endif // RUNTIME_VM_IMAGE_SNAPSHOT_H_