// Copyright 2010 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifdef ENABLE_GDB_JIT_INTERFACE
#include "v8.h"
#include "gdb-jit.h"
#include "bootstrapper.h"
#include "compiler.h"
#include "global-handles.h"
#include "messages.h"
#include "natives.h"
namespace v8 {
namespace internal {
class ELF;
class Writer BASE_EMBEDDED {
public:
explicit Writer(ELF* elf)
: elf_(elf),
position_(0),
capacity_(1024),
buffer_(reinterpret_cast<byte*>(malloc(capacity_))) {
}
~Writer() {
free(buffer_);
}
uintptr_t position() const {
return position_;
}
template<typename T>
class Slot {
public:
Slot(Writer* w, uintptr_t offset) : w_(w), offset_(offset) { }
T* operator-> () {
return w_->RawSlotAt<T>(offset_);
}
void set(const T& value) {
*w_->RawSlotAt<T>(offset_) = value;
}
Slot<T> at(int i) {
return Slot<T>(w_, offset_ + sizeof(T) * i);
}
private:
Writer* w_;
uintptr_t offset_;
};
template<typename T>
void Write(const T& val) {
Ensure(position_ + sizeof(T));
*RawSlotAt<T>(position_) = val;
position_ += sizeof(T);
}
template<typename T>
Slot<T> SlotAt(uintptr_t offset) {
Ensure(offset + sizeof(T));
return Slot<T>(this, offset);
}
template<typename T>
Slot<T> CreateSlotHere() {
return CreateSlotsHere<T>(1);
}
template<typename T>
Slot<T> CreateSlotsHere(uint32_t count) {
uintptr_t slot_position = position_;
position_ += sizeof(T) * count;
Ensure(position_);
return SlotAt<T>(slot_position);
}
void Ensure(uintptr_t pos) {
if (capacity_ < pos) {
while (capacity_ < pos) capacity_ *= 2;
buffer_ = reinterpret_cast<byte*>(realloc(buffer_, capacity_));
}
}
ELF* elf() { return elf_; }
byte* buffer() { return buffer_; }
void Align(uintptr_t align) {
uintptr_t delta = position_ % align;
if (delta == 0) return;
uintptr_t padding = align - delta;
Ensure(position_ += padding);
ASSERT((position_ % align) == 0);
}
void WriteULEB128(uintptr_t value) {
do {
uint8_t byte = value & 0x7F;
value >>= 7;
if (value != 0) byte |= 0x80;
Write<uint8_t>(byte);
} while (value != 0);
}
void WriteSLEB128(intptr_t value) {
bool more = true;
while (more) {
int8_t byte = value & 0x7F;
bool byte_sign = byte & 0x40;
value >>= 7;
if ((value == 0 && !byte_sign) || (value == -1 && byte_sign)) {
more = false;
} else {
byte |= 0x80;
}
Write<int8_t>(byte);
}
}
void WriteString(const char* str) {
do {
Write<char>(*str);
} while (*str++);
}
private:
template<typename T> friend class Slot;
template<typename T>
T* RawSlotAt(uintptr_t offset) {
ASSERT(offset < capacity_ && offset + sizeof(T) <= capacity_);
return reinterpret_cast<T*>(&buffer_[offset]);
}
ELF* elf_;
uintptr_t position_;
uintptr_t capacity_;
byte* buffer_;
};
class StringTable;
class ELFSection : public ZoneObject {
public:
struct Header {
uint32_t name;
uint32_t type;
uintptr_t flags;
uintptr_t address;
uintptr_t offset;
uintptr_t size;
uint32_t link;
uint32_t info;
uintptr_t alignment;
uintptr_t entry_size;
};
enum Type {
TYPE_NULL = 0,
TYPE_PROGBITS = 1,
TYPE_SYMTAB = 2,
TYPE_STRTAB = 3,
TYPE_RELA = 4,
TYPE_HASH = 5,
TYPE_DYNAMIC = 6,
TYPE_NOTE = 7,
TYPE_NOBITS = 8,
TYPE_REL = 9,
TYPE_SHLIB = 10,
TYPE_DYNSYM = 11,
TYPE_LOPROC = 0x70000000,
TYPE_X86_64_UNWIND = 0x70000001,
TYPE_HIPROC = 0x7fffffff,
TYPE_LOUSER = 0x80000000,
TYPE_HIUSER = 0xffffffff
};
enum Flags {
FLAG_WRITE = 1,
FLAG_ALLOC = 2,
FLAG_EXEC = 4
};
enum SpecialIndexes {
INDEX_ABSOLUTE = 0xfff1
};
ELFSection(const char* name, Type type, uintptr_t align)
: name_(name), type_(type), align_(align) { }
virtual ~ELFSection() { }
void PopulateHeader(Writer::Slot<Header> header, StringTable* strtab);
virtual void WriteBody(Writer::Slot<Header> header, Writer* w) {
uintptr_t start = w->position();
if (WriteBody(w)) {
uintptr_t end = w->position();
header->offset = start;
header->size = end - start;
}
}
virtual bool WriteBody(Writer* w) {
return false;
}
uint16_t index() const { return index_; }
void set_index(uint16_t index) { index_ = index; }
protected:
virtual void PopulateHeader(Writer::Slot<Header> header) {
header->flags = 0;
header->address = 0;
header->offset = 0;
header->size = 0;
header->link = 0;
header->info = 0;
header->entry_size = 0;
}
private:
const char* name_;
Type type_;
uintptr_t align_;
uint16_t index_;
};
class FullHeaderELFSection : public ELFSection {
public:
FullHeaderELFSection(const char* name,
Type type,
uintptr_t align,
uintptr_t addr,
uintptr_t offset,
uintptr_t size,
uintptr_t flags)
: ELFSection(name, type, align),
addr_(addr),
offset_(offset),
size_(size),
flags_(flags) { }
protected:
virtual void PopulateHeader(Writer::Slot<Header> header) {
ELFSection::PopulateHeader(header);
header->address = addr_;
header->offset = offset_;
header->size = size_;
header->flags = flags_;
}
private:
uintptr_t addr_;
uintptr_t offset_;
uintptr_t size_;
uintptr_t flags_;
};
class StringTable : public ELFSection {
public:
explicit StringTable(const char* name)
: ELFSection(name, TYPE_STRTAB, 1), writer_(NULL), offset_(0), size_(0) {
}
uintptr_t Add(const char* str) {
if (*str == '\0') return 0;
uintptr_t offset = size_;
WriteString(str);
return offset;
}
void AttachWriter(Writer* w) {
writer_ = w;
offset_ = writer_->position();
// First entry in the string table should be an empty string.
WriteString("");
}
void DetachWriter() {
writer_ = NULL;
}
virtual void WriteBody(Writer::Slot<Header> header, Writer* w) {
ASSERT(writer_ == NULL);
header->offset = offset_;
header->size = size_;
}
private:
void WriteString(const char* str) {
uintptr_t written = 0;
do {
writer_->Write(*str);
written++;
} while (*str++);
size_ += written;
}
Writer* writer_;
uintptr_t offset_;
uintptr_t size_;
};
void ELFSection::PopulateHeader(Writer::Slot<ELFSection::Header> header,
StringTable* strtab) {
header->name = strtab->Add(name_);
header->type = type_;
header->alignment = align_;
PopulateHeader(header);
}
class ELF BASE_EMBEDDED {
public:
ELF() : sections_(6) {
sections_.Add(new ELFSection("", ELFSection::TYPE_NULL, 0));
sections_.Add(new StringTable(".shstrtab"));
}
void Write(Writer* w) {
WriteHeader(w);
WriteSectionTable(w);
WriteSections(w);
}
ELFSection* SectionAt(uint32_t index) {
return sections_[index];
}
uint32_t AddSection(ELFSection* section) {
sections_.Add(section);
section->set_index(sections_.length() - 1);
return sections_.length() - 1;
}
private:
struct ELFHeader {
uint8_t ident[16];
uint16_t type;
uint16_t machine;
uint32_t version;
uintptr_t entry;
uintptr_t pht_offset;
uintptr_t sht_offset;
uint32_t flags;
uint16_t header_size;
uint16_t pht_entry_size;
uint16_t pht_entry_num;
uint16_t sht_entry_size;
uint16_t sht_entry_num;
uint16_t sht_strtab_index;
};
void WriteHeader(Writer* w) {
ASSERT(w->position() == 0);
Writer::Slot<ELFHeader> header = w->CreateSlotHere<ELFHeader>();
#if defined(V8_TARGET_ARCH_IA32) || defined(V8_TARGET_ARCH_ARM)
const uint8_t ident[16] =
{ 0x7f, 'E', 'L', 'F', 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0};
#elif defined(V8_TARGET_ARCH_X64)
const uint8_t ident[16] =
{ 0x7f, 'E', 'L', 'F', 2, 1, 1, 0, 0, 0 , 0, 0, 0, 0, 0, 0};
#else
#error Unsupported target architecture.
#endif
memcpy(header->ident, ident, 16);
header->type = 1;
#if defined(V8_TARGET_ARCH_IA32)
header->machine = 3;
#elif defined(V8_TARGET_ARCH_X64)
// Processor identification value for x64 is 62 as defined in
// System V ABI, AMD64 Supplement
// http://www.x86-64.org/documentation/abi.pdf
header->machine = 62;
#elif defined(V8_TARGET_ARCH_ARM)
// Set to EM_ARM, defined as 40, in "ARM ELF File Format" at
// infocenter.arm.com/help/topic/com.arm.doc.dui0101a/DUI0101A_Elf.pdf
header->machine = 40;
#else
#error Unsupported target architecture.
#endif
header->version = 1;
header->entry = 0;
header->pht_offset = 0;
header->sht_offset = sizeof(ELFHeader); // Section table follows header.
header->flags = 0;
header->header_size = sizeof(ELFHeader);
header->pht_entry_size = 0;
header->pht_entry_num = 0;
header->sht_entry_size = sizeof(ELFSection::Header);
header->sht_entry_num = sections_.length();
header->sht_strtab_index = 1;
}
void WriteSectionTable(Writer* w) {
// Section headers table immediately follows file header.
ASSERT(w->position() == sizeof(ELFHeader));
Writer::Slot<ELFSection::Header> headers =
w->CreateSlotsHere<ELFSection::Header>(sections_.length());
// String table for section table is the first section.
StringTable* strtab = static_cast<StringTable*>(SectionAt(1));
strtab->AttachWriter(w);
for (int i = 0, length = sections_.length();
i < length;
i++) {
sections_[i]->PopulateHeader(headers.at(i), strtab);
}
strtab->DetachWriter();
}
int SectionHeaderPosition(uint32_t section_index) {
return sizeof(ELFHeader) + sizeof(ELFSection::Header) * section_index;
}
void WriteSections(Writer* w) {
Writer::Slot<ELFSection::Header> headers =
w->SlotAt<ELFSection::Header>(sizeof(ELFHeader));
for (int i = 0, length = sections_.length();
i < length;
i++) {
sections_[i]->WriteBody(headers.at(i), w);
}
}
ZoneList<ELFSection*> sections_;
};
class ELFSymbol BASE_EMBEDDED {
public:
enum Type {
TYPE_NOTYPE = 0,
TYPE_OBJECT = 1,
TYPE_FUNC = 2,
TYPE_SECTION = 3,
TYPE_FILE = 4,
TYPE_LOPROC = 13,
TYPE_HIPROC = 15
};
enum Binding {
BIND_LOCAL = 0,
BIND_GLOBAL = 1,
BIND_WEAK = 2,
BIND_LOPROC = 13,
BIND_HIPROC = 15
};
ELFSymbol(const char* name,
uintptr_t value,
uintptr_t size,
Binding binding,
Type type,
uint16_t section)
: name(name),
value(value),
size(size),
info((binding << 4) | type),
other(0),
section(section) {
}
Binding binding() const {
return static_cast<Binding>(info >> 4);
}
#if defined(V8_TARGET_ARCH_IA32) || defined(V8_TARGET_ARCH_ARM)
struct SerializedLayout {
SerializedLayout(uint32_t name,
uintptr_t value,
uintptr_t size,
Binding binding,
Type type,
uint16_t section)
: name(name),
value(value),
size(size),
info((binding << 4) | type),
other(0),
section(section) {
}
uint32_t name;
uintptr_t value;
uintptr_t size;
uint8_t info;
uint8_t other;
uint16_t section;
};
#elif defined(V8_TARGET_ARCH_X64)
struct SerializedLayout {
SerializedLayout(uint32_t name,
uintptr_t value,
uintptr_t size,
Binding binding,
Type type,
uint16_t section)
: name(name),
info((binding << 4) | type),
other(0),
section(section),
value(value),
size(size) {
}
uint32_t name;
uint8_t info;
uint8_t other;
uint16_t section;
uintptr_t value;
uintptr_t size;
};
#endif
void Write(Writer::Slot<SerializedLayout> s, StringTable* t) {
// Convert symbol names from strings to indexes in the string table.
s->name = t->Add(name);
s->value = value;
s->size = size;
s->info = info;
s->other = other;
s->section = section;
}
private:
const char* name;
uintptr_t value;
uintptr_t size;
uint8_t info;
uint8_t other;
uint16_t section;
};
class ELFSymbolTable : public ELFSection {
public:
explicit ELFSymbolTable(const char* name)
: ELFSection(name, TYPE_SYMTAB, sizeof(uintptr_t)),
locals_(1),
globals_(1) {
}
virtual void WriteBody(Writer::Slot<Header> header, Writer* w) {
w->Align(header->alignment);
int total_symbols = locals_.length() + globals_.length() + 1;
header->offset = w->position();
Writer::Slot<ELFSymbol::SerializedLayout> symbols =
w->CreateSlotsHere<ELFSymbol::SerializedLayout>(total_symbols);
header->size = w->position() - header->offset;
// String table for this symbol table should follow it in the section table.
StringTable* strtab =
static_cast<StringTable*>(w->elf()->SectionAt(index() + 1));
strtab->AttachWriter(w);
symbols.at(0).set(ELFSymbol::SerializedLayout(0,
0,
0,
ELFSymbol::BIND_LOCAL,
ELFSymbol::TYPE_NOTYPE,
0));
WriteSymbolsList(&locals_, symbols.at(1), strtab);
WriteSymbolsList(&globals_, symbols.at(locals_.length() + 1), strtab);
strtab->DetachWriter();
}
void Add(const ELFSymbol& symbol) {
if (symbol.binding() == ELFSymbol::BIND_LOCAL) {
locals_.Add(symbol);
} else {
globals_.Add(symbol);
}
}
protected:
virtual void PopulateHeader(Writer::Slot<Header> header) {
ELFSection::PopulateHeader(header);
// We are assuming that string table will follow symbol table.
header->link = index() + 1;
header->info = locals_.length() + 1;
header->entry_size = sizeof(ELFSymbol::SerializedLayout);
}
private:
void WriteSymbolsList(const ZoneList<ELFSymbol>* src,
Writer::Slot<ELFSymbol::SerializedLayout> dst,
StringTable* strtab) {
for (int i = 0, len = src->length();
i < len;
i++) {
src->at(i).Write(dst.at(i), strtab);
}
}
ZoneList<ELFSymbol> locals_;
ZoneList<ELFSymbol> globals_;
};
class CodeDescription BASE_EMBEDDED {
public:
#ifdef V8_TARGET_ARCH_X64
enum StackState {
POST_RBP_PUSH,
POST_RBP_SET,
POST_RBP_POP,
STACK_STATE_MAX
};
#endif
CodeDescription(const char* name,
Code* code,
Handle<Script> script,
GDBJITLineInfo* lineinfo,
GDBJITInterface::CodeTag tag)
: name_(name),
code_(code),
script_(script),
lineinfo_(lineinfo),
tag_(tag) {
}
const char* name() const {
return name_;
}
GDBJITLineInfo* lineinfo() const {
return lineinfo_;
}
GDBJITInterface::CodeTag tag() const {
return tag_;
}
uintptr_t CodeStart() const {
return reinterpret_cast<uintptr_t>(code_->instruction_start());
}
uintptr_t CodeEnd() const {
return reinterpret_cast<uintptr_t>(code_->instruction_end());
}
uintptr_t CodeSize() const {
return CodeEnd() - CodeStart();
}
bool IsLineInfoAvailable() {
return !script_.is_null() &&
script_->source()->IsString() &&
script_->HasValidSource() &&
script_->name()->IsString() &&
lineinfo_ != NULL;
}
#ifdef V8_TARGET_ARCH_X64
uintptr_t GetStackStateStartAddress(StackState state) const {
ASSERT(state < STACK_STATE_MAX);
return stack_state_start_addresses_[state];
}
void SetStackStateStartAddress(StackState state, uintptr_t addr) {
ASSERT(state < STACK_STATE_MAX);
stack_state_start_addresses_[state] = addr;
}
#endif
SmartPointer<char> GetFilename() {
return String::cast(script_->name())->ToCString();
}
int GetScriptLineNumber(int pos) {
return GetScriptLineNumberSafe(script_, pos) + 1;
}
private:
const char* name_;
Code* code_;
Handle<Script> script_;
GDBJITLineInfo* lineinfo_;
GDBJITInterface::CodeTag tag_;
#ifdef V8_TARGET_ARCH_X64
uintptr_t stack_state_start_addresses_[STACK_STATE_MAX];
#endif
};
static void CreateSymbolsTable(CodeDescription* desc,
ELF* elf,
int text_section_index) {
ELFSymbolTable* symtab = new ELFSymbolTable(".symtab");
StringTable* strtab = new StringTable(".strtab");
// Symbol table should be followed by the linked string table.
elf->AddSection(symtab);
elf->AddSection(strtab);
symtab->Add(ELFSymbol("V8 Code",
0,
0,
ELFSymbol::BIND_LOCAL,
ELFSymbol::TYPE_FILE,
ELFSection::INDEX_ABSOLUTE));
symtab->Add(ELFSymbol(desc->name(),
0,
desc->CodeSize(),
ELFSymbol::BIND_GLOBAL,
ELFSymbol::TYPE_FUNC,
text_section_index));
}
class DebugInfoSection : public ELFSection {
public:
explicit DebugInfoSection(CodeDescription* desc)
: ELFSection(".debug_info", TYPE_PROGBITS, 1), desc_(desc) { }
bool WriteBody(Writer* w) {
Writer::Slot<uint32_t> size = w->CreateSlotHere<uint32_t>();
uintptr_t start = w->position();
w->Write<uint16_t>(2); // DWARF version.
w->Write<uint32_t>(0); // Abbreviation table offset.
w->Write<uint8_t>(sizeof(intptr_t));
w->WriteULEB128(1); // Abbreviation code.
w->WriteString(*desc_->GetFilename());
w->Write<intptr_t>(desc_->CodeStart());
w->Write<intptr_t>(desc_->CodeStart() + desc_->CodeSize());
w->Write<uint32_t>(0);
size.set(static_cast<uint32_t>(w->position() - start));
return true;
}
private:
CodeDescription* desc_;
};
class DebugAbbrevSection : public ELFSection {
public:
DebugAbbrevSection() : ELFSection(".debug_abbrev", TYPE_PROGBITS, 1) { }
// DWARF2 standard, figure 14.
enum DWARF2Tags {
DW_TAG_COMPILE_UNIT = 0x11
};
// DWARF2 standard, figure 16.
enum DWARF2ChildrenDetermination {
DW_CHILDREN_NO = 0,
DW_CHILDREN_YES = 1
};
// DWARF standard, figure 17.
enum DWARF2Attribute {
DW_AT_NAME = 0x3,
DW_AT_STMT_LIST = 0x10,
DW_AT_LOW_PC = 0x11,
DW_AT_HIGH_PC = 0x12
};
// DWARF2 standard, figure 19.
enum DWARF2AttributeForm {
DW_FORM_ADDR = 0x1,
DW_FORM_STRING = 0x8,
DW_FORM_DATA4 = 0x6
};
bool WriteBody(Writer* w) {
w->WriteULEB128(1);
w->WriteULEB128(DW_TAG_COMPILE_UNIT);
w->Write<uint8_t>(DW_CHILDREN_NO);
w->WriteULEB128(DW_AT_NAME);
w->WriteULEB128(DW_FORM_STRING);
w->WriteULEB128(DW_AT_LOW_PC);
w->WriteULEB128(DW_FORM_ADDR);
w->WriteULEB128(DW_AT_HIGH_PC);
w->WriteULEB128(DW_FORM_ADDR);
w->WriteULEB128(DW_AT_STMT_LIST);
w->WriteULEB128(DW_FORM_DATA4);
w->WriteULEB128(0);
w->WriteULEB128(0);
w->WriteULEB128(0);
return true;
}
};
class DebugLineSection : public ELFSection {
public:
explicit DebugLineSection(CodeDescription* desc)
: ELFSection(".debug_line", TYPE_PROGBITS, 1),
desc_(desc) { }
// DWARF2 standard, figure 34.
enum DWARF2Opcodes {
DW_LNS_COPY = 1,
DW_LNS_ADVANCE_PC = 2,
DW_LNS_ADVANCE_LINE = 3,
DW_LNS_SET_FILE = 4,
DW_LNS_SET_COLUMN = 5,
DW_LNS_NEGATE_STMT = 6
};
// DWARF2 standard, figure 35.
enum DWARF2ExtendedOpcode {
DW_LNE_END_SEQUENCE = 1,
DW_LNE_SET_ADDRESS = 2,
DW_LNE_DEFINE_FILE = 3
};
bool WriteBody(Writer* w) {
// Write prologue.
Writer::Slot<uint32_t> total_length = w->CreateSlotHere<uint32_t>();
uintptr_t start = w->position();
// Used for special opcodes
const int8_t line_base = 1;
const uint8_t line_range = 7;
const int8_t max_line_incr = (line_base + line_range - 1);
const uint8_t opcode_base = DW_LNS_NEGATE_STMT + 1;
w->Write<uint16_t>(2); // Field version.
Writer::Slot<uint32_t> prologue_length = w->CreateSlotHere<uint32_t>();
uintptr_t prologue_start = w->position();
w->Write<uint8_t>(1); // Field minimum_instruction_length.
w->Write<uint8_t>(1); // Field default_is_stmt.
w->Write<int8_t>(line_base); // Field line_base.
w->Write<uint8_t>(line_range); // Field line_range.
w->Write<uint8_t>(opcode_base); // Field opcode_base.
w->Write<uint8_t>(0); // DW_LNS_COPY operands count.
w->Write<uint8_t>(1); // DW_LNS_ADVANCE_PC operands count.
w->Write<uint8_t>(1); // DW_LNS_ADVANCE_LINE operands count.
w->Write<uint8_t>(1); // DW_LNS_SET_FILE operands count.
w->Write<uint8_t>(1); // DW_LNS_SET_COLUMN operands count.
w->Write<uint8_t>(0); // DW_LNS_NEGATE_STMT operands count.
w->Write<uint8_t>(0); // Empty include_directories sequence.
w->WriteString(*desc_->GetFilename()); // File name.
w->WriteULEB128(0); // Current directory.
w->WriteULEB128(0); // Unknown modification time.
w->WriteULEB128(0); // Unknown file size.
w->Write<uint8_t>(0);
prologue_length.set(static_cast<uint32_t>(w->position() - prologue_start));
WriteExtendedOpcode(w, DW_LNE_SET_ADDRESS, sizeof(intptr_t));
w->Write<intptr_t>(desc_->CodeStart());
w->Write<uint8_t>(DW_LNS_COPY);
intptr_t pc = 0;
intptr_t line = 1;
bool is_statement = true;
List<GDBJITLineInfo::PCInfo>* pc_info = desc_->lineinfo()->pc_info();
pc_info->Sort(&ComparePCInfo);
int pc_info_length = pc_info->length();
for (int i = 0; i < pc_info_length; i++) {
GDBJITLineInfo::PCInfo* info = &pc_info->at(i);
ASSERT(info->pc_ >= pc);
// Reduce bloating in the debug line table by removing duplicate line
// entries (per DWARF2 standard).
intptr_t new_line = desc_->GetScriptLineNumber(info->pos_);
if (new_line == line) {
continue;
}
// Mark statement boundaries. For a better debugging experience, mark
// the last pc address in the function as a statement (e.g. "}"), so that
// a user can see the result of the last line executed in the function,
// should control reach the end.
if ((i+1) == pc_info_length) {
if (!is_statement) {
w->Write<uint8_t>(DW_LNS_NEGATE_STMT);
}
} else if (is_statement != info->is_statement_) {
w->Write<uint8_t>(DW_LNS_NEGATE_STMT);
is_statement = !is_statement;
}
// Generate special opcodes, if possible. This results in more compact
// debug line tables. See the DWARF 2.0 standard to learn more about
// special opcodes.
uintptr_t pc_diff = info->pc_ - pc;
intptr_t line_diff = new_line - line;
// Compute special opcode (see DWARF 2.0 standard)
intptr_t special_opcode = (line_diff - line_base) +
(line_range * pc_diff) + opcode_base;
// If special_opcode is less than or equal to 255, it can be used as a
// special opcode. If line_diff is larger than the max line increment
// allowed for a special opcode, or if line_diff is less than the minimum
// line that can be added to the line register (i.e. line_base), then
// special_opcode can't be used.
if ((special_opcode >= opcode_base) && (special_opcode <= 255) &&
(line_diff <= max_line_incr) && (line_diff >= line_base)) {
w->Write<uint8_t>(special_opcode);
} else {
w->Write<uint8_t>(DW_LNS_ADVANCE_PC);
w->WriteSLEB128(pc_diff);
w->Write<uint8_t>(DW_LNS_ADVANCE_LINE);
w->WriteSLEB128(line_diff);
w->Write<uint8_t>(DW_LNS_COPY);
}
// Increment the pc and line operands.
pc += pc_diff;
line += line_diff;
}
// Advance the pc to the end of the routine, since the end sequence opcode
// requires this.
w->Write<uint8_t>(DW_LNS_ADVANCE_PC);
w->WriteSLEB128(desc_->CodeSize() - pc);
WriteExtendedOpcode(w, DW_LNE_END_SEQUENCE, 0);
total_length.set(static_cast<uint32_t>(w->position() - start));
return true;
}
private:
void WriteExtendedOpcode(Writer* w,
DWARF2ExtendedOpcode op,
size_t operands_size) {
w->Write<uint8_t>(0);
w->WriteULEB128(operands_size + 1);
w->Write<uint8_t>(op);
}
static int ComparePCInfo(const GDBJITLineInfo::PCInfo* a,
const GDBJITLineInfo::PCInfo* b) {
if (a->pc_ == b->pc_) {
if (a->is_statement_ != b->is_statement_) {
return b->is_statement_ ? +1 : -1;
}
return 0;
} else if (a->pc_ > b->pc_) {
return +1;
} else {
return -1;
}
}
CodeDescription* desc_;
};
#ifdef V8_TARGET_ARCH_X64
class UnwindInfoSection : public ELFSection {
public:
explicit UnwindInfoSection(CodeDescription *desc);
virtual bool WriteBody(Writer *w);
int WriteCIE(Writer *w);
void WriteFDE(Writer *w, int);
void WriteFDEStateOnEntry(Writer *w);
void WriteFDEStateAfterRBPPush(Writer *w);
void WriteFDEStateAfterRBPSet(Writer *w);
void WriteFDEStateAfterRBPPop(Writer *w);
void WriteLength(Writer *w,
Writer::Slot<uint32_t>* length_slot,
int initial_position);
private:
CodeDescription *desc_;
// DWARF3 Specification, Table 7.23
enum CFIInstructions {
DW_CFA_ADVANCE_LOC = 0x40,
DW_CFA_OFFSET = 0x80,
DW_CFA_RESTORE = 0xC0,
DW_CFA_NOP = 0x00,
DW_CFA_SET_LOC = 0x01,
DW_CFA_ADVANCE_LOC1 = 0x02,
DW_CFA_ADVANCE_LOC2 = 0x03,
DW_CFA_ADVANCE_LOC4 = 0x04,
DW_CFA_OFFSET_EXTENDED = 0x05,
DW_CFA_RESTORE_EXTENDED = 0x06,
DW_CFA_UNDEFINED = 0x07,
DW_CFA_SAME_VALUE = 0x08,
DW_CFA_REGISTER = 0x09,
DW_CFA_REMEMBER_STATE = 0x0A,
DW_CFA_RESTORE_STATE = 0x0B,
DW_CFA_DEF_CFA = 0x0C,
DW_CFA_DEF_CFA_REGISTER = 0x0D,
DW_CFA_DEF_CFA_OFFSET = 0x0E,
DW_CFA_DEF_CFA_EXPRESSION = 0x0F,
DW_CFA_EXPRESSION = 0x10,
DW_CFA_OFFSET_EXTENDED_SF = 0x11,
DW_CFA_DEF_CFA_SF = 0x12,
DW_CFA_DEF_CFA_OFFSET_SF = 0x13,
DW_CFA_VAL_OFFSET = 0x14,
DW_CFA_VAL_OFFSET_SF = 0x15,
DW_CFA_VAL_EXPRESSION = 0x16
};
// System V ABI, AMD64 Supplement, Version 0.99.5, Figure 3.36
enum RegisterMapping {
// Only the relevant ones have been added to reduce clutter.
AMD64_RBP = 6,
AMD64_RSP = 7,
AMD64_RA = 16
};
enum CFIConstants {
CIE_ID = 0,
CIE_VERSION = 1,
CODE_ALIGN_FACTOR = 1,
DATA_ALIGN_FACTOR = 1,
RETURN_ADDRESS_REGISTER = AMD64_RA
};
};
void UnwindInfoSection::WriteLength(Writer *w,
Writer::Slot<uint32_t>* length_slot,
int initial_position) {
uint32_t align = (w->position() - initial_position) % kPointerSize;
if (align != 0) {
for (uint32_t i = 0; i < (kPointerSize - align); i++) {
w->Write<uint8_t>(DW_CFA_NOP);
}
}
ASSERT((w->position() - initial_position) % kPointerSize == 0);
length_slot->set(w->position() - initial_position);
}
UnwindInfoSection::UnwindInfoSection(CodeDescription *desc)
: ELFSection(".eh_frame", TYPE_X86_64_UNWIND, 1), desc_(desc)
{ }
int UnwindInfoSection::WriteCIE(Writer *w) {
Writer::Slot<uint32_t> cie_length_slot = w->CreateSlotHere<uint32_t>();
uint32_t cie_position = w->position();
// Write out the CIE header. Currently no 'common instructions' are
// emitted onto the CIE; every FDE has its own set of instructions.
w->Write<uint32_t>(CIE_ID);
w->Write<uint8_t>(CIE_VERSION);
w->Write<uint8_t>(0); // Null augmentation string.
w->WriteSLEB128(CODE_ALIGN_FACTOR);
w->WriteSLEB128(DATA_ALIGN_FACTOR);
w->Write<uint8_t>(RETURN_ADDRESS_REGISTER);
WriteLength(w, &cie_length_slot, cie_position);
return cie_position;
}
void UnwindInfoSection::WriteFDE(Writer *w, int cie_position) {
// The only FDE for this function. The CFA is the current RBP.
Writer::Slot<uint32_t> fde_length_slot = w->CreateSlotHere<uint32_t>();
int fde_position = w->position();
w->Write<int32_t>(fde_position - cie_position + 4);
w->Write<uintptr_t>(desc_->CodeStart());
w->Write<uintptr_t>(desc_->CodeSize());
WriteFDEStateOnEntry(w);
WriteFDEStateAfterRBPPush(w);
WriteFDEStateAfterRBPSet(w);
WriteFDEStateAfterRBPPop(w);
WriteLength(w, &fde_length_slot, fde_position);
}
void UnwindInfoSection::WriteFDEStateOnEntry(Writer *w) {
// The first state, just after the control has been transferred to the the
// function.
// RBP for this function will be the value of RSP after pushing the RBP
// for the previous function. The previous RBP has not been pushed yet.
w->Write<uint8_t>(DW_CFA_DEF_CFA_SF);
w->WriteULEB128(AMD64_RSP);
w->WriteSLEB128(-kPointerSize);
// The RA is stored at location CFA + kCallerPCOffset. This is an invariant,
// and hence omitted from the next states.
w->Write<uint8_t>(DW_CFA_OFFSET_EXTENDED);
w->WriteULEB128(AMD64_RA);
w->WriteSLEB128(StandardFrameConstants::kCallerPCOffset);
// The RBP of the previous function is still in RBP.
w->Write<uint8_t>(DW_CFA_SAME_VALUE);
w->WriteULEB128(AMD64_RBP);
// Last location described by this entry.
w->Write<uint8_t>(DW_CFA_SET_LOC);
w->Write<uint64_t>(
desc_->GetStackStateStartAddress(CodeDescription::POST_RBP_PUSH));
}
void UnwindInfoSection::WriteFDEStateAfterRBPPush(Writer *w) {
// The second state, just after RBP has been pushed.
// RBP / CFA for this function is now the current RSP, so just set the
// offset from the previous rule (from -8) to 0.
w->Write<uint8_t>(DW_CFA_DEF_CFA_OFFSET);
w->WriteULEB128(0);
// The previous RBP is stored at CFA + kCallerFPOffset. This is an invariant
// in this and the next state, and hence omitted in the next state.
w->Write<uint8_t>(DW_CFA_OFFSET_EXTENDED);
w->WriteULEB128(AMD64_RBP);
w->WriteSLEB128(StandardFrameConstants::kCallerFPOffset);
// Last location described by this entry.
w->Write<uint8_t>(DW_CFA_SET_LOC);
w->Write<uint64_t>(
desc_->GetStackStateStartAddress(CodeDescription::POST_RBP_SET));
}
void UnwindInfoSection::WriteFDEStateAfterRBPSet(Writer *w) {
// The third state, after the RBP has been set.
// The CFA can now directly be set to RBP.
w->Write<uint8_t>(DW_CFA_DEF_CFA);
w->WriteULEB128(AMD64_RBP);
w->WriteULEB128(0);
// Last location described by this entry.
w->Write<uint8_t>(DW_CFA_SET_LOC);
w->Write<uint64_t>(
desc_->GetStackStateStartAddress(CodeDescription::POST_RBP_POP));
}
void UnwindInfoSection::WriteFDEStateAfterRBPPop(Writer *w) {
// The fourth (final) state. The RBP has been popped (just before issuing a
// return).
// The CFA can is now calculated in the same way as in the first state.
w->Write<uint8_t>(DW_CFA_DEF_CFA_SF);
w->WriteULEB128(AMD64_RSP);
w->WriteSLEB128(-kPointerSize);
// The RBP
w->Write<uint8_t>(DW_CFA_OFFSET_EXTENDED);
w->WriteULEB128(AMD64_RBP);
w->WriteSLEB128(StandardFrameConstants::kCallerFPOffset);
// Last location described by this entry.
w->Write<uint8_t>(DW_CFA_SET_LOC);
w->Write<uint64_t>(desc_->CodeEnd());
}
bool UnwindInfoSection::WriteBody(Writer *w) {
uint32_t cie_position = WriteCIE(w);
WriteFDE(w, cie_position);
return true;
}
#endif // V8_TARGET_ARCH_X64
static void CreateDWARFSections(CodeDescription* desc, ELF* elf) {
if (desc->IsLineInfoAvailable()) {
elf->AddSection(new DebugInfoSection(desc));
elf->AddSection(new DebugAbbrevSection);
elf->AddSection(new DebugLineSection(desc));
}
#ifdef V8_TARGET_ARCH_X64
elf->AddSection(new UnwindInfoSection(desc));
#endif
}
// -------------------------------------------------------------------
// Binary GDB JIT Interface as described in
// http://sourceware.org/gdb/onlinedocs/gdb/Declarations.html
extern "C" {
typedef enum {
JIT_NOACTION = 0,
JIT_REGISTER_FN,
JIT_UNREGISTER_FN
} JITAction;
struct JITCodeEntry {
JITCodeEntry* next_;
JITCodeEntry* prev_;
Address symfile_addr_;
uint64_t symfile_size_;
};
struct JITDescriptor {
uint32_t version_;
uint32_t action_flag_;
JITCodeEntry *relevant_entry_;
JITCodeEntry *first_entry_;
};
// GDB will place breakpoint into this function.
// To prevent GCC from inlining or removing it we place noinline attribute
// and inline assembler statement inside.
void __attribute__((noinline)) __jit_debug_register_code() {
__asm__("");
}
// GDB will inspect contents of this descriptor.
// Static initialization is necessary to prevent GDB from seeing
// uninitialized descriptor.
JITDescriptor __jit_debug_descriptor = { 1, 0, 0, 0 };
}
static JITCodeEntry* CreateCodeEntry(Address symfile_addr,
uintptr_t symfile_size) {
JITCodeEntry* entry = static_cast<JITCodeEntry*>(
malloc(sizeof(JITCodeEntry) + symfile_size));
entry->symfile_addr_ = reinterpret_cast<Address>(entry + 1);
entry->symfile_size_ = symfile_size;
memcpy(entry->symfile_addr_, symfile_addr, symfile_size);
entry->prev_ = entry->next_ = NULL;
return entry;
}
static void DestroyCodeEntry(JITCodeEntry* entry) {
free(entry);
}
static void RegisterCodeEntry(JITCodeEntry* entry) {
#if defined(DEBUG) && !defined(WIN32)
static int file_num = 0;
if (FLAG_gdbjit_dump) {
static const int kMaxFileNameSize = 64;
static const char* kElfFilePrefix = "/tmp/elfdump";
static const char* kObjFileExt = ".o";
char file_name[64];
OS::SNPrintF(Vector<char>(file_name, kMaxFileNameSize), "%s%d%s",
kElfFilePrefix, file_num++, kObjFileExt);
WriteBytes(file_name, entry->symfile_addr_, entry->symfile_size_);
}
#endif
entry->next_ = __jit_debug_descriptor.first_entry_;
if (entry->next_ != NULL) entry->next_->prev_ = entry;
__jit_debug_descriptor.first_entry_ =
__jit_debug_descriptor.relevant_entry_ = entry;
__jit_debug_descriptor.action_flag_ = JIT_REGISTER_FN;
__jit_debug_register_code();
}
static void UnregisterCodeEntry(JITCodeEntry* entry) {
if (entry->prev_ != NULL) {
entry->prev_->next_ = entry->next_;
} else {
__jit_debug_descriptor.first_entry_ = entry->next_;
}
if (entry->next_ != NULL) {
entry->next_->prev_ = entry->prev_;
}
__jit_debug_descriptor.relevant_entry_ = entry;
__jit_debug_descriptor.action_flag_ = JIT_UNREGISTER_FN;
__jit_debug_register_code();
}
static JITCodeEntry* CreateELFObject(CodeDescription* desc) {
ZoneScope zone_scope(DELETE_ON_EXIT);
ELF elf;
Writer w(&elf);
int text_section_index = elf.AddSection(
new FullHeaderELFSection(".text",
ELFSection::TYPE_NOBITS,
kCodeAlignment,
desc->CodeStart(),
0,
desc->CodeSize(),
ELFSection::FLAG_ALLOC | ELFSection::FLAG_EXEC));
CreateSymbolsTable(desc, &elf, text_section_index);
CreateDWARFSections(desc, &elf);
elf.Write(&w);
return CreateCodeEntry(w.buffer(), w.position());
}
static bool SameCodeObjects(void* key1, void* key2) {
return key1 == key2;
}
static HashMap* GetEntries() {
static HashMap* entries = NULL;
if (entries == NULL) {
entries = new HashMap(&SameCodeObjects);
}
return entries;
}
static uint32_t HashForCodeObject(Code* code) {
static const uintptr_t kGoldenRatio = 2654435761u;
uintptr_t hash = reinterpret_cast<uintptr_t>(code->address());
return static_cast<uint32_t>((hash >> kCodeAlignmentBits) * kGoldenRatio);
}
static const intptr_t kLineInfoTag = 0x1;
static bool IsLineInfoTagged(void* ptr) {
return 0 != (reinterpret_cast<intptr_t>(ptr) & kLineInfoTag);
}
static void* TagLineInfo(GDBJITLineInfo* ptr) {
return reinterpret_cast<void*>(
reinterpret_cast<intptr_t>(ptr) | kLineInfoTag);
}
static GDBJITLineInfo* UntagLineInfo(void* ptr) {
return reinterpret_cast<GDBJITLineInfo*>(
reinterpret_cast<intptr_t>(ptr) & ~kLineInfoTag);
}
void GDBJITInterface::AddCode(Handle<String> name,
Handle<Script> script,
Handle<Code> code) {
if (!FLAG_gdbjit) return;
// Force initialization of line_ends array.
GetScriptLineNumber(script, 0);
if (!name.is_null()) {
SmartPointer<char> name_cstring = name->ToCString(DISALLOW_NULLS);
AddCode(*name_cstring, *code, GDBJITInterface::FUNCTION, *script);
} else {
AddCode("", *code, GDBJITInterface::FUNCTION, *script);
}
}
static void AddUnwindInfo(CodeDescription *desc) {
#ifdef V8_TARGET_ARCH_X64
if (desc->tag() == GDBJITInterface::FUNCTION) {
// To avoid propagating unwinding information through
// compilation pipeline we use an approximation.
// For most use cases this should not affect usability.
static const int kFramePointerPushOffset = 1;
static const int kFramePointerSetOffset = 4;
static const int kFramePointerPopOffset = -3;
uintptr_t frame_pointer_push_address =
desc->CodeStart() + kFramePointerPushOffset;
uintptr_t frame_pointer_set_address =
desc->CodeStart() + kFramePointerSetOffset;
uintptr_t frame_pointer_pop_address =
desc->CodeEnd() + kFramePointerPopOffset;
desc->SetStackStateStartAddress(CodeDescription::POST_RBP_PUSH,
frame_pointer_push_address);
desc->SetStackStateStartAddress(CodeDescription::POST_RBP_SET,
frame_pointer_set_address);
desc->SetStackStateStartAddress(CodeDescription::POST_RBP_POP,
frame_pointer_pop_address);
} else {
desc->SetStackStateStartAddress(CodeDescription::POST_RBP_PUSH,
desc->CodeStart());
desc->SetStackStateStartAddress(CodeDescription::POST_RBP_SET,
desc->CodeStart());
desc->SetStackStateStartAddress(CodeDescription::POST_RBP_POP,
desc->CodeEnd());
}
#endif // V8_TARGET_ARCH_X64
}
Mutex* GDBJITInterface::mutex_ = OS::CreateMutex();
void GDBJITInterface::AddCode(const char* name,
Code* code,
GDBJITInterface::CodeTag tag,
Script* script) {
if (!FLAG_gdbjit) return;
ScopedLock lock(mutex_);
AssertNoAllocation no_gc;
HashMap::Entry* e = GetEntries()->Lookup(code, HashForCodeObject(code), true);
if (e->value != NULL && !IsLineInfoTagged(e->value)) return;
GDBJITLineInfo* lineinfo = UntagLineInfo(e->value);
CodeDescription code_desc(name,
code,
script != NULL ? Handle<Script>(script)
: Handle<Script>(),
lineinfo,
tag);
if (!FLAG_gdbjit_full && !code_desc.IsLineInfoAvailable()) {
delete lineinfo;
GetEntries()->Remove(code, HashForCodeObject(code));
return;
}
AddUnwindInfo(&code_desc);
JITCodeEntry* entry = CreateELFObject(&code_desc);
ASSERT(!IsLineInfoTagged(entry));
delete lineinfo;
e->value = entry;
RegisterCodeEntry(entry);
}
void GDBJITInterface::AddCode(GDBJITInterface::CodeTag tag,
const char* name,
Code* code) {
if (!FLAG_gdbjit) return;
EmbeddedVector<char, 256> buffer;
StringBuilder builder(buffer.start(), buffer.length());
builder.AddString(Tag2String(tag));
if ((name != NULL) && (*name != '\0')) {
builder.AddString(": ");
builder.AddString(name);
} else {
builder.AddFormatted(": code object %p", static_cast<void*>(code));
}
AddCode(builder.Finalize(), code, tag);
}
void GDBJITInterface::AddCode(GDBJITInterface::CodeTag tag,
String* name,
Code* code) {
if (!FLAG_gdbjit) return;
AddCode(tag, name != NULL ? *name->ToCString(DISALLOW_NULLS) : NULL, code);
}
void GDBJITInterface::AddCode(GDBJITInterface::CodeTag tag, Code* code) {
if (!FLAG_gdbjit) return;
AddCode(tag, "", code);
}
void GDBJITInterface::RemoveCode(Code* code) {
if (!FLAG_gdbjit) return;
ScopedLock lock(mutex_);
HashMap::Entry* e = GetEntries()->Lookup(code,
HashForCodeObject(code),
false);
if (e == NULL) return;
if (IsLineInfoTagged(e->value)) {
delete UntagLineInfo(e->value);
} else {
JITCodeEntry* entry = static_cast<JITCodeEntry*>(e->value);
UnregisterCodeEntry(entry);
DestroyCodeEntry(entry);
}
e->value = NULL;
GetEntries()->Remove(code, HashForCodeObject(code));
}
void GDBJITInterface::RegisterDetailedLineInfo(Code* code,
GDBJITLineInfo* line_info) {
ScopedLock lock(mutex_);
ASSERT(!IsLineInfoTagged(line_info));
HashMap::Entry* e = GetEntries()->Lookup(code, HashForCodeObject(code), true);
ASSERT(e->value == NULL);
e->value = TagLineInfo(line_info);
}
} } // namespace v8::internal
#endif