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LinkEdit.hpp
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LinkEdit.hpp
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/* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-*
*
* Copyright (c) 2009-2010 Apple Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
#ifndef __LINKEDIT_HPP__
#define __LINKEDIT_HPP__
#include <stdlib.h>
#include <sys/types.h>
#include <errno.h>
#include <limits.h>
#include <unistd.h>
#include <CommonCrypto/CommonDigest.h>
#include <CommonCrypto/CommonDigestSPI.h>
#include <vector>
#include <unordered_map>
#include "Options.h"
#include "ld.hpp"
#include "Architectures.hpp"
#include "MachOFileAbstraction.hpp"
#include "libcodedirectory.h"
#ifndef CS_LINKER_SIGNED
#define CS_LINKER_SIGNED 0x00020000 /* Automatically signed by the linker */
#endif
namespace ld {
namespace tool {
class ByteStream {
private:
std::vector<uint8_t> _data;
public:
std::vector<uint8_t>& bytes() { return _data; }
unsigned long size() const { return _data.size(); }
void reserve(unsigned long l) { _data.reserve(l); }
const uint8_t* start() const { return &_data[0]; }
void append_uleb128(uint64_t value) {
uint8_t byte;
do {
byte = value & 0x7F;
value &= ~0x7F;
if ( value != 0 )
byte |= 0x80;
_data.push_back(byte);
value = value >> 7;
} while( byte >= 0x80 );
}
void append_sleb128(int64_t value) {
bool isNeg = ( value < 0 );
uint8_t byte;
bool more;
do {
byte = value & 0x7F;
value = value >> 7;
if ( isNeg )
more = ( (value != -1) || ((byte & 0x40) == 0) );
else
more = ( (value != 0) || ((byte & 0x40) != 0) );
if ( more )
byte |= 0x80;
_data.push_back(byte);
}
while( more );
}
void append_delta_encoded_uleb128_run(uint64_t start, const std::vector<uint64_t>& locations) {
uint64_t lastAddr = start;
for(std::vector<uint64_t>::const_iterator it = locations.begin(); it != locations.end(); ++it) {
uint64_t nextAddr = *it;
uint64_t delta = nextAddr - lastAddr;
assert(delta != 0);
append_uleb128(delta);
lastAddr = nextAddr;
}
}
void append_string(const char* str) {
for (const char* s = str; *s != '\0'; ++s)
_data.push_back(*s);
_data.push_back('\0');
}
void append_byte(uint8_t byte) {
_data.push_back(byte);
}
void append_mem(const void* mem, size_t len) {
_data.insert(_data.end(), (uint8_t*)mem, (uint8_t*)mem + len);
}
// adds 'len' bytes to buffer and returns pointer to start of block
uint8_t* alloc(size_t len) {
size_t start = _data.size();
for (size_t i=0; i < len; ++i)
_data.push_back(0);
return &_data[start];
}
static unsigned int uleb128_size(uint64_t value) {
uint32_t result = 0;
do {
value = value >> 7;
++result;
} while ( value != 0 );
return result;
}
void pad_to_size(unsigned int alignment) {
while ( (_data.size() % alignment) != 0 )
_data.push_back(0);
}
};
class LinkEditAtom : public ld::Atom
{
public:
// overrides of ld::Atom
virtual ld::File* file() const { return NULL; }
virtual uint64_t objectAddress() const { return 0; }
virtual uint64_t size() const;
virtual void copyRawContent(uint8_t buffer[]) const;
virtual void encode() const = 0;
const uint8_t* rawContent() const { return this->_encodedData.start(); }
LinkEditAtom(const Options& opts, ld::Internal& state,
OutputFile& writer, const ld::Section& sect,
unsigned int pointerSize)
: ld::Atom(sect, ld::Atom::definitionRegular,
ld::Atom::combineNever, ld::Atom::scopeTranslationUnit,
ld::Atom::typeUnclassified, ld::Atom::symbolTableNotIn,
false, false, false, ld::Atom::Alignment(log2(pointerSize))),
_options(opts), _state(state), _writer(writer),
_encoded(false) { }
protected:
const Options& _options;
ld::Internal& _state;
OutputFile& _writer;
mutable ByteStream _encodedData;
mutable bool _encoded;
};
uint64_t LinkEditAtom::size() const
{
assert(_encoded);
return _encodedData.size();
}
void LinkEditAtom::copyRawContent(uint8_t buffer[]) const
{
assert(_encoded);
memcpy(buffer, _encodedData.start(), _encodedData.size());
}
template <typename A>
class RebaseInfoAtom : public LinkEditAtom
{
public:
RebaseInfoAtom(const Options& opts, ld::Internal& state, OutputFile& writer)
: LinkEditAtom(opts, state, writer, _s_section, sizeof(pint_t)) { _encoded = true; }
// overrides of ld::Atom
virtual const char* name() const { return "rebase info"; }
// overrides of LinkEditAtom
virtual void encode() const;
private:
void encodeV1() const;
struct rebase_tmp
{
rebase_tmp(uint8_t op, uint64_t p1, uint64_t p2=0) : opcode(op), operand1(p1), operand2(p2) {}
uint8_t opcode;
uint64_t operand1;
uint64_t operand2;
};
typedef typename A::P P;
typedef typename A::P::E E;
typedef typename A::P::uint_t pint_t;
static ld::Section _s_section;
};
template <typename A>
ld::Section RebaseInfoAtom<A>::_s_section("__LINKEDIT", "__rebase", ld::Section::typeLinkEdit, true);
template <typename A>
void RebaseInfoAtom<A>::encode() const
{
// omit relocs if this was supposed to be PIE but PIE not possible
if ( _options.positionIndependentExecutable() && this->_writer.pieDisabled )
return;
// sort rebase info by type, then address
std::vector<OutputFile::RebaseInfo>& info = this->_writer._rebaseInfo;
if (info.empty())
return;
std::sort(info.begin(), info.end());
// use encoding based on target minOS
if ( _options.useLinkedListBinding() && !this->_writer._hasUnalignedFixup ) {
if ( info.back()._type != REBASE_TYPE_POINTER )
throw "unsupported rebase type with linked list opcodes";
// As the binding and rebasing are both linked lists, just use the binds
// to do everything.
} else {
encodeV1();
}
}
template <typename A>
void RebaseInfoAtom<A>::encodeV1() const
{
std::vector<OutputFile::RebaseInfo>& info = this->_writer._rebaseInfo;
// convert to temp encoding that can be more easily optimized
std::vector<rebase_tmp> mid;
uint64_t curSegStart = 0;
uint64_t curSegEnd = 0;
uint32_t curSegIndex = 0;
uint8_t type = 0;
uint64_t address = (uint64_t)(-1);
for (std::vector<OutputFile::RebaseInfo>::iterator it = info.begin(); it != info.end(); ++it) {
if ( type != it->_type ) {
mid.push_back(rebase_tmp(REBASE_OPCODE_SET_TYPE_IMM, it->_type));
type = it->_type;
}
if ( address != it->_address ) {
if ( (it->_address < curSegStart) || ( it->_address >= curSegEnd) ) {
if ( ! this->_writer.findSegment(this->_state, it->_address, &curSegStart, &curSegEnd, &curSegIndex) )
throw "binding address outside range of any segment";
mid.push_back(rebase_tmp(REBASE_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB, curSegIndex, it->_address - curSegStart));
}
else {
mid.push_back(rebase_tmp(REBASE_OPCODE_ADD_ADDR_ULEB, it->_address-address));
}
address = it->_address;
}
mid.push_back(rebase_tmp(REBASE_OPCODE_DO_REBASE_ULEB_TIMES, 1));
address += sizeof(pint_t);
if ( address >= curSegEnd )
address = 0;
}
mid.push_back(rebase_tmp(REBASE_OPCODE_DONE, 0));
// optimize phase 1, compress packed runs of pointers
rebase_tmp* dst = &mid[0];
for (const rebase_tmp* src = &mid[0]; src->opcode != REBASE_OPCODE_DONE; ++src) {
if ( (src->opcode == REBASE_OPCODE_DO_REBASE_ULEB_TIMES) && (src->operand1 == 1) ) {
*dst = *src++;
while (src->opcode == REBASE_OPCODE_DO_REBASE_ULEB_TIMES ) {
dst->operand1 += src->operand1;
++src;
}
--src;
++dst;
}
else {
*dst++ = *src;
}
}
dst->opcode = REBASE_OPCODE_DONE;
// optimize phase 2, combine rebase/add pairs
dst = &mid[0];
for (const rebase_tmp* src = &mid[0]; src->opcode != REBASE_OPCODE_DONE; ++src) {
if ( (src->opcode == REBASE_OPCODE_DO_REBASE_ULEB_TIMES)
&& (src->operand1 == 1)
&& (src[1].opcode == REBASE_OPCODE_ADD_ADDR_ULEB)) {
dst->opcode = REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB;
dst->operand1 = src[1].operand1;
++src;
++dst;
}
else {
*dst++ = *src;
}
}
dst->opcode = REBASE_OPCODE_DONE;
// optimize phase 3, compress packed runs of REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB with
// same addr delta into one REBASE_OPCODE_DO_REBASE_ULEB_TIMES_SKIPPING_ULEB
dst = &mid[0];
for (const rebase_tmp* src = &mid[0]; src->opcode != REBASE_OPCODE_DONE; ++src) {
uint64_t delta = src->operand1;
if ( (src->opcode == REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB)
&& (src[1].opcode == REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB)
&& (src[2].opcode == REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB)
&& (src[1].operand1 == delta)
&& (src[2].operand1 == delta) ) {
// found at least three in a row, this is worth compressing
dst->opcode = REBASE_OPCODE_DO_REBASE_ULEB_TIMES_SKIPPING_ULEB;
dst->operand1 = 1;
dst->operand2 = delta;
++src;
while ( (src->opcode == REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB)
&& (src->operand1 == delta) ) {
dst->operand1++;
++src;
}
--src;
++dst;
}
else {
*dst++ = *src;
}
}
dst->opcode = REBASE_OPCODE_DONE;
// optimize phase 4, use immediate encodings
for (rebase_tmp* p = &mid[0]; p->opcode != REBASE_OPCODE_DONE; ++p) {
if ( (p->opcode == REBASE_OPCODE_ADD_ADDR_ULEB)
&& (p->operand1 < (15*sizeof(pint_t)))
&& ((p->operand1 % sizeof(pint_t)) == 0) ) {
p->opcode = REBASE_OPCODE_ADD_ADDR_IMM_SCALED;
p->operand1 = p->operand1/sizeof(pint_t);
}
else if ( (p->opcode == REBASE_OPCODE_DO_REBASE_ULEB_TIMES) && (p->operand1 < 15) ) {
p->opcode = REBASE_OPCODE_DO_REBASE_IMM_TIMES;
}
}
// convert to compressed encoding
const static bool log = false;
this->_encodedData.reserve(info.size()*2);
bool done = false;
for (typename std::vector<rebase_tmp>::iterator it = mid.begin(); !done && it != mid.end() ; ++it) {
switch ( it->opcode ) {
case REBASE_OPCODE_DONE:
if ( log ) fprintf(stderr, "REBASE_OPCODE_DONE()\n");
done = true;
break;
case REBASE_OPCODE_SET_TYPE_IMM:
if ( log ) fprintf(stderr, "REBASE_OPCODE_SET_TYPE_IMM(%lld)\n", it->operand1);
this->_encodedData.append_byte(REBASE_OPCODE_SET_TYPE_IMM | it->operand1);
break;
case REBASE_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB:
if ( log ) fprintf(stderr, "REBASE_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB(%lld, 0x%llX)\n", it->operand1, it->operand2);
this->_encodedData.append_byte(REBASE_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB | it->operand1);
this->_encodedData.append_uleb128(it->operand2);
break;
case REBASE_OPCODE_ADD_ADDR_ULEB:
if ( log ) fprintf(stderr, "REBASE_OPCODE_ADD_ADDR_ULEB(0x%llX)\n", it->operand1);
this->_encodedData.append_byte(REBASE_OPCODE_ADD_ADDR_ULEB);
this->_encodedData.append_uleb128(it->operand1);
break;
case REBASE_OPCODE_ADD_ADDR_IMM_SCALED:
if ( log ) fprintf(stderr, "REBASE_OPCODE_ADD_ADDR_IMM_SCALED(%lld=0x%llX)\n", it->operand1, it->operand1*sizeof(pint_t));
this->_encodedData.append_byte(REBASE_OPCODE_ADD_ADDR_IMM_SCALED | it->operand1 );
break;
case REBASE_OPCODE_DO_REBASE_IMM_TIMES:
if ( log ) fprintf(stderr, "REBASE_OPCODE_DO_REBASE_IMM_TIMES(%lld)\n", it->operand1);
this->_encodedData.append_byte(REBASE_OPCODE_DO_REBASE_IMM_TIMES | it->operand1);
break;
case REBASE_OPCODE_DO_REBASE_ULEB_TIMES:
if ( log ) fprintf(stderr, "REBASE_OPCODE_DO_REBASE_ULEB_TIMES(%lld)\n", it->operand1);
this->_encodedData.append_byte(REBASE_OPCODE_DO_REBASE_ULEB_TIMES);
this->_encodedData.append_uleb128(it->operand1);
break;
case REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB:
if ( log ) fprintf(stderr, "REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB(0x%llX)\n", it->operand1);
this->_encodedData.append_byte(REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB);
this->_encodedData.append_uleb128(it->operand1);
break;
case REBASE_OPCODE_DO_REBASE_ULEB_TIMES_SKIPPING_ULEB:
if ( log ) fprintf(stderr, "REBASE_OPCODE_DO_REBASE_ULEB_TIMES_SKIPPING_ULEB(%lld, %lld)\n", it->operand1, it->operand2);
this->_encodedData.append_byte(REBASE_OPCODE_DO_REBASE_ULEB_TIMES_SKIPPING_ULEB);
this->_encodedData.append_uleb128(it->operand1);
this->_encodedData.append_uleb128(it->operand2);
break;
}
}
// align to pointer size
this->_encodedData.pad_to_size(sizeof(pint_t));
this->_encoded = true;
if (log) fprintf(stderr, "total rebase info size = %ld\n", this->_encodedData.size());
}
template <typename A>
class BindingInfoAtom : public LinkEditAtom
{
public:
BindingInfoAtom(const Options& opts, ld::Internal& state, OutputFile& writer)
: LinkEditAtom(opts, state, writer, _s_section, sizeof(pint_t)) { }
// overrides of ld::Atom
virtual const char* name() const { return "binding info"; }
// overrides of LinkEditAtom
virtual void encode() const;
private:
void encodeV1() const;
void encodeV2() const;
typedef typename A::P P;
typedef typename A::P::E E;
typedef typename A::P::uint_t pint_t;
struct binding_tmp
{
binding_tmp(uint8_t op, uint64_t p1, uint64_t p2=0, const char* s=NULL)
: opcode(op), operand1(p1), operand2(p2), name(s) {}
uint8_t opcode;
uint64_t operand1;
uint64_t operand2;
const char* name;
};
static ld::Section _s_section;
};
template <typename A>
ld::Section BindingInfoAtom<A>::_s_section("__LINKEDIT", "__binding", ld::Section::typeLinkEdit, true);
template <typename A>
void BindingInfoAtom<A>::encode() const
{
// use encoding based on target minOS
if ( _options.useLinkedListBinding() && !this->_writer._hasUnalignedFixup ) {
encodeV2();
} else {
encodeV1();
}
}
template <typename A>
void BindingInfoAtom<A>::encodeV1() const
{
// sort by library, symbol, type, then address
std::vector<OutputFile::BindingInfo>& info = this->_writer._bindingInfo;
std::sort(info.begin(), info.end());
// convert to temp encoding that can be more easily optimized
std::vector<binding_tmp> mid;
uint64_t curSegStart = 0;
uint64_t curSegEnd = 0;
uint32_t curSegIndex = 0;
int ordinal = 0x80000000;
const char* symbolName = NULL;
uint8_t type = 0;
uint64_t address = (uint64_t)(-1);
int64_t addend = 0;
for (std::vector<OutputFile::BindingInfo>::const_iterator it = info.begin(); it != info.end(); ++it) {
if ( ordinal != it->_libraryOrdinal ) {
if ( it->_libraryOrdinal <= 0 ) {
// special lookups are encoded as negative numbers in BindingInfo
mid.push_back(binding_tmp(BIND_OPCODE_SET_DYLIB_SPECIAL_IMM, it->_libraryOrdinal));
}
else {
mid.push_back(binding_tmp(BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB, it->_libraryOrdinal));
}
ordinal = it->_libraryOrdinal;
}
if ( symbolName != it->_symbolName ) {
mid.push_back(binding_tmp(BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM, it->_flags, 0, it->_symbolName));
symbolName = it->_symbolName;
}
if ( type != it->_type ) {
mid.push_back(binding_tmp(BIND_OPCODE_SET_TYPE_IMM, it->_type));
type = it->_type;
}
if ( address != it->_address ) {
if ( (it->_address < curSegStart) || ( it->_address >= curSegEnd) ) {
if ( ! this->_writer.findSegment(this->_state, it->_address, &curSegStart, &curSegEnd, &curSegIndex) )
throw "binding address outside range of any segment";
mid.push_back(binding_tmp(BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB, curSegIndex, it->_address - curSegStart));
}
else {
mid.push_back(binding_tmp(BIND_OPCODE_ADD_ADDR_ULEB, it->_address-address));
}
address = it->_address;
}
if ( addend != it->_addend ) {
mid.push_back(binding_tmp(BIND_OPCODE_SET_ADDEND_SLEB, it->_addend));
addend = it->_addend;
}
mid.push_back(binding_tmp(BIND_OPCODE_DO_BIND, 0));
address += sizeof(pint_t);
}
mid.push_back(binding_tmp(BIND_OPCODE_DONE, 0));
// optimize phase 1, combine bind/add pairs
binding_tmp* dst = &mid[0];
for (const binding_tmp* src = &mid[0]; src->opcode != BIND_OPCODE_DONE; ++src) {
if ( (src->opcode == BIND_OPCODE_DO_BIND)
&& (src[1].opcode == BIND_OPCODE_ADD_ADDR_ULEB) ) {
dst->opcode = BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB;
dst->operand1 = src[1].operand1;
++src;
++dst;
}
else {
*dst++ = *src;
}
}
dst->opcode = BIND_OPCODE_DONE;
// optimize phase 2, compress packed runs of BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB with
// same addr delta into one BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB
dst = &mid[0];
for (const binding_tmp* src = &mid[0]; src->opcode != BIND_OPCODE_DONE; ++src) {
uint64_t delta = src->operand1;
if ( (src->opcode == BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB)
&& (src[1].opcode == BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB)
&& (src[1].operand1 == delta) ) {
// found at least two in a row, this is worth compressing
dst->opcode = BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB;
dst->operand1 = 1;
dst->operand2 = delta;
++src;
while ( (src->opcode == BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB)
&& (src->operand1 == delta) ) {
dst->operand1++;
++src;
}
--src;
++dst;
}
else {
*dst++ = *src;
}
}
dst->opcode = BIND_OPCODE_DONE;
// optimize phase 3, use immediate encodings
for (binding_tmp* p = &mid[0]; p->opcode != REBASE_OPCODE_DONE; ++p) {
if ( (p->opcode == BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB)
&& (p->operand1 < (15*sizeof(pint_t)))
&& ((p->operand1 % sizeof(pint_t)) == 0) ) {
p->opcode = BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED;
p->operand1 = p->operand1/sizeof(pint_t);
}
else if ( (p->opcode == BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB) && (p->operand1 <= 15) ) {
p->opcode = BIND_OPCODE_SET_DYLIB_ORDINAL_IMM;
}
}
dst->opcode = BIND_OPCODE_DONE;
// convert to compressed encoding
const static bool log = false;
this->_encodedData.reserve(info.size()*2);
bool done = false;
for (typename std::vector<binding_tmp>::iterator it = mid.begin(); !done && it != mid.end() ; ++it) {
switch ( it->opcode ) {
case BIND_OPCODE_DONE:
if ( log ) fprintf(stderr, "BIND_OPCODE_DONE()\n");
done = true;
break;
case BIND_OPCODE_SET_DYLIB_ORDINAL_IMM:
if ( log ) fprintf(stderr, "BIND_OPCODE_SET_DYLIB_ORDINAL_IMM(%lld)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_SET_DYLIB_ORDINAL_IMM | it->operand1);
break;
case BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB:
if ( log ) fprintf(stderr, "BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB(%lld)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB);
this->_encodedData.append_uleb128(it->operand1);
break;
case BIND_OPCODE_SET_DYLIB_SPECIAL_IMM:
if ( log ) fprintf(stderr, "BIND_OPCODE_SET_DYLIB_SPECIAL_IMM(%lld)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_SET_DYLIB_SPECIAL_IMM | (it->operand1 & BIND_IMMEDIATE_MASK));
break;
case BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM:
if ( log ) fprintf(stderr, "BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM(0x%0llX, %s)\n", it->operand1, it->name);
this->_encodedData.append_byte(BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM | it->operand1);
this->_encodedData.append_string(it->name);
break;
case BIND_OPCODE_SET_TYPE_IMM:
if ( log ) fprintf(stderr, "BIND_OPCODE_SET_TYPE_IMM(%lld)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_SET_TYPE_IMM | it->operand1);
break;
case BIND_OPCODE_SET_ADDEND_SLEB:
if ( log ) fprintf(stderr, "BIND_OPCODE_SET_ADDEND_SLEB(%lld)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_SET_ADDEND_SLEB);
this->_encodedData.append_sleb128(it->operand1);
break;
case BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB:
if ( log ) fprintf(stderr, "BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB(%lld, 0x%llX)\n", it->operand1, it->operand2);
this->_encodedData.append_byte(BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB | it->operand1);
this->_encodedData.append_uleb128(it->operand2);
break;
case BIND_OPCODE_ADD_ADDR_ULEB:
if ( log ) fprintf(stderr, "BIND_OPCODE_ADD_ADDR_ULEB(0x%llX)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_ADD_ADDR_ULEB);
this->_encodedData.append_uleb128(it->operand1);
break;
case BIND_OPCODE_DO_BIND:
if ( log ) fprintf(stderr, "BIND_OPCODE_DO_BIND()\n");
this->_encodedData.append_byte(BIND_OPCODE_DO_BIND);
break;
case BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB:
if ( log ) fprintf(stderr, "BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB(0x%llX)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB);
this->_encodedData.append_uleb128(it->operand1);
break;
case BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED:
if ( log ) fprintf(stderr, "BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED(%lld=0x%llX)\n", it->operand1, it->operand1*sizeof(pint_t));
this->_encodedData.append_byte(BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED | it->operand1 );
break;
case BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB:
if ( log ) fprintf(stderr, "BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB(%lld, %lld)\n", it->operand1, it->operand2);
this->_encodedData.append_byte(BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB);
this->_encodedData.append_uleb128(it->operand1);
this->_encodedData.append_uleb128(it->operand2);
break;
}
}
// align to pointer size
this->_encodedData.pad_to_size(sizeof(pint_t));
this->_encoded = true;
if (log) fprintf(stderr, "total binding info size = %ld\n", this->_encodedData.size());
}
template <typename A>
void BindingInfoAtom<A>::encodeV2() const
{
std::vector<OutputFile::BindingInfo>& bindInfo = this->_writer._bindingInfo;
std::vector<OutputFile::RebaseInfo>& rebaseInfo = this->_writer._rebaseInfo;
const static bool log = false;
std::sort(bindInfo.begin(), bindInfo.end());
// convert to temp encoding that can be more easily optimized
std::vector<binding_tmp> mid;
uint64_t curSegStart = 0;
uint64_t curSegEnd = 0;
uint32_t curSegIndex = 0;
int ordinal = 0x80000000;
const char* symbolName = NULL;
uint8_t type = 0;
uint64_t address = (uint64_t)(-1);
int64_t addend = 0;
uint64_t numBinds = (uint64_t)(-1);
for (std::vector<OutputFile::BindingInfo>::iterator it = bindInfo.begin(); it != bindInfo.end(); ++it) {
bool madeChange = false;
if ( ordinal != it->_libraryOrdinal ) {
if ( it->_libraryOrdinal <= 0 ) {
// special lookups are encoded as negative numbers in BindingInfo
mid.push_back(binding_tmp(BIND_OPCODE_SET_DYLIB_SPECIAL_IMM, it->_libraryOrdinal));
}
else if ( it->_libraryOrdinal <= 15 ) {
mid.push_back(binding_tmp(BIND_OPCODE_SET_DYLIB_ORDINAL_IMM, it->_libraryOrdinal));
}
else {
mid.push_back(binding_tmp(BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB, it->_libraryOrdinal));
}
ordinal = it->_libraryOrdinal;
madeChange = true;
}
if ( symbolName != it->_symbolName ) {
mid.push_back(binding_tmp(BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM, it->_flags, 0, it->_symbolName));
symbolName = it->_symbolName;
madeChange = true;
}
if ( type != it->_type ) {
if ( it->_type != BIND_TYPE_POINTER )
throw "unsupported bind type with linked list opcodes";
mid.push_back(binding_tmp(BIND_OPCODE_SET_TYPE_IMM, it->_type));
type = it->_type;
madeChange = true;
}
if ( address != it->_address ) {
// Note, we don't push the addresses here. That is all done later with the threaded chains
if ( (it->_address < curSegStart) || ( it->_address >= curSegEnd) ) {
if ( ! this->_writer.findSegment(this->_state, it->_address, &curSegStart, &curSegEnd, &curSegIndex) )
throw "binding address outside range of any segment";
}
address = it->_address;
}
if ( addend != it->_addend ) {
mid.push_back(binding_tmp(BIND_OPCODE_SET_ADDEND_SLEB, it->_addend));
addend = it->_addend;
madeChange = true;
}
if (madeChange) {
++numBinds;
mid.push_back(binding_tmp(BIND_OPCODE_DO_BIND, 0));
}
it->_threadedBindOrdinal = numBinds;
}
// We can only support 2^16 bind ordinals.
if ( (numBinds > 0x10000) && (numBinds != (uint64_t)(-1)) )
throwf("too many binds (%llu). The limit is 65536", numBinds);
// Now that we have the bind ordinal table populate, set the page starts.
std::vector<int64_t>& threadedRebaseBindIndices = this->_writer._threadedRebaseBindIndices;
threadedRebaseBindIndices.reserve(bindInfo.size() + rebaseInfo.size());
for (int64_t i = 0, e = rebaseInfo.size(); i != e; ++i)
threadedRebaseBindIndices.push_back(-i);
for (int64_t i = 0, e = bindInfo.size(); i != e; ++i)
threadedRebaseBindIndices.push_back(i + 1);
// Now sort the entries by address.
std::sort(threadedRebaseBindIndices.begin(), threadedRebaseBindIndices.end(),
[&rebaseInfo, &bindInfo](int64_t indexA, int64_t indexB) {
if (indexA == indexB)
return false;
uint64_t addressA = indexA <= 0 ? rebaseInfo[-indexA]._address : bindInfo[indexA - 1]._address;
uint64_t addressB = indexB <= 0 ? rebaseInfo[-indexB]._address : bindInfo[indexB - 1]._address;
assert(addressA != addressB);
return addressA < addressB;
});
curSegStart = 0;
curSegEnd = 0;
curSegIndex = 0;
uint64_t prevPageIndex = 0;
for (int64_t entryIndex : threadedRebaseBindIndices) {
OutputFile::RebaseInfo* rebase = nullptr;
OutputFile::BindingInfo* bind = nullptr;
uint64_t address = 0;
if (entryIndex <= 0) {
rebase = &rebaseInfo[-entryIndex];
address = rebase->_address;
} else {
bind = &bindInfo[entryIndex - 1];
address = bind->_address;
}
assert((address & 7) == 0);
bool newSegment = false;
if ( (address < curSegStart) || ( address >= curSegEnd) ) {
// Start of a new segment.
if ( ! this->_writer.findSegment(this->_state, address, &curSegStart, &curSegEnd, &curSegIndex) )
throw "binding address outside range of any segment";
newSegment = true;
}
// At this point we know we have the page starts array space reserved
// so set the page start for this entry if we haven't got one already.
uint64_t pageIndex = ( address - curSegStart ) / 4096;
if ( newSegment || (pageIndex != prevPageIndex) ) {
mid.push_back(binding_tmp(BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB, curSegIndex, address - curSegStart));
mid.push_back(binding_tmp(BIND_OPCODE_THREADED | BIND_SUBOPCODE_THREADED_APPLY, 0));
}
prevPageIndex = pageIndex;
}
mid.push_back(binding_tmp(BIND_OPCODE_DONE, 0));
// convert to compressed encoding
this->_encodedData.reserve(bindInfo.size()*2);
// First push the total number of binds so that we can allocate space for this in dyld.
if ( log ) fprintf(stderr, "BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB(%lld)\n", numBinds + 1);
this->_encodedData.append_byte(BIND_OPCODE_THREADED | BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB);
this->_encodedData.append_uleb128(numBinds + 1);
bool done = false;
for (typename std::vector<binding_tmp>::iterator it = mid.begin(); !done && it != mid.end() ; ++it) {
switch ( it->opcode ) {
case BIND_OPCODE_DONE:
if ( log ) fprintf(stderr, "BIND_OPCODE_DONE()\n");
done = true;
break;
case BIND_OPCODE_SET_DYLIB_ORDINAL_IMM:
if ( log ) fprintf(stderr, "BIND_OPCODE_SET_DYLIB_ORDINAL_IMM(%lld)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_SET_DYLIB_ORDINAL_IMM | it->operand1);
break;
case BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB:
if ( log ) fprintf(stderr, "BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB(%lld)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB);
this->_encodedData.append_uleb128(it->operand1);
break;
case BIND_OPCODE_SET_DYLIB_SPECIAL_IMM:
if ( log ) fprintf(stderr, "BIND_OPCODE_SET_DYLIB_SPECIAL_IMM(%lld)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_SET_DYLIB_SPECIAL_IMM | (it->operand1 & BIND_IMMEDIATE_MASK));
break;
case BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM:
if ( log ) fprintf(stderr, "BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM(0x%0llX, %s)\n", it->operand1, it->name);
this->_encodedData.append_byte(BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM | it->operand1);
this->_encodedData.append_string(it->name);
break;
case BIND_OPCODE_SET_TYPE_IMM:
if ( log ) fprintf(stderr, "BIND_OPCODE_SET_TYPE_IMM(%lld)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_SET_TYPE_IMM | it->operand1);
break;
case BIND_OPCODE_SET_ADDEND_SLEB:
if ( log ) fprintf(stderr, "BIND_OPCODE_SET_ADDEND_SLEB(%lld)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_SET_ADDEND_SLEB);
this->_encodedData.append_sleb128(it->operand1);
break;
case BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB:
if ( log ) fprintf(stderr, "BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB(%lld, 0x%llX)\n", it->operand1, it->operand2);
this->_encodedData.append_byte(BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB | it->operand1);
this->_encodedData.append_uleb128(it->operand2);
break;
case BIND_OPCODE_ADD_ADDR_ULEB:
if ( log ) fprintf(stderr, "BIND_OPCODE_ADD_ADDR_ULEB(0x%llX)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_ADD_ADDR_ULEB);
this->_encodedData.append_uleb128(it->operand1);
break;
case BIND_OPCODE_DO_BIND:
if ( log ) fprintf(stderr, "BIND_OPCODE_DO_BIND()\n");
this->_encodedData.append_byte(BIND_OPCODE_DO_BIND);
break;
case BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB:
if ( log ) fprintf(stderr, "BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB(0x%llX)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB);
this->_encodedData.append_uleb128(it->operand1);
break;
case BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED:
if ( log ) fprintf(stderr, "BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED(%lld=0x%llX)\n", it->operand1, it->operand1*sizeof(pint_t));
this->_encodedData.append_byte(BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED | it->operand1 );
break;
case BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB:
if ( log ) fprintf(stderr, "BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB(%lld, %lld)\n", it->operand1, it->operand2);
this->_encodedData.append_byte(BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB);
this->_encodedData.append_uleb128(it->operand1);
this->_encodedData.append_uleb128(it->operand2);
break;
case BIND_OPCODE_THREADED | BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB:
if ( log ) fprintf(stderr, "BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB(%lld)\n", it->operand1);
this->_encodedData.append_byte(BIND_OPCODE_THREADED | BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB);
this->_encodedData.append_uleb128(it->operand1);
break;
case BIND_OPCODE_THREADED | BIND_SUBOPCODE_THREADED_APPLY:
this->_encodedData.append_byte(BIND_OPCODE_THREADED | BIND_SUBOPCODE_THREADED_APPLY);
if ( log ) fprintf(stderr, "BIND_SUBOPCODE_THREADED_APPLY()\n");
break;
}
}
// align to pointer size
this->_encodedData.append_byte(BIND_OPCODE_DONE);
this->_encodedData.pad_to_size(sizeof(pint_t));
this->_encoded = true;
if (log) fprintf(stderr, "total binding info size = %ld\n", this->_encodedData.size());
}
template <typename A>
class WeakBindingInfoAtom : public LinkEditAtom
{
public:
WeakBindingInfoAtom(const Options& opts, ld::Internal& state, OutputFile& writer)
: LinkEditAtom(opts, state, writer, _s_section, sizeof(pint_t)) { _encoded = true; }
// overrides of ld::Atom
virtual const char* name() const { return "weak binding info"; }
// overrides of LinkEditAtom
virtual void encode() const;
private:
typedef typename A::P P;
typedef typename A::P::E E;
typedef typename A::P::uint_t pint_t;
struct WeakBindingSorter
{
bool operator()(const OutputFile::BindingInfo& left, const OutputFile::BindingInfo& right)
{
// sort by symbol, type, address
if ( left._symbolName != right._symbolName )
return ( strcmp(left._symbolName, right._symbolName) < 0 );
if ( left._type != right._type )
return (left._type < right._type);
return (left._address < right._address);
}
};
struct binding_tmp
{
binding_tmp(uint8_t op, uint64_t p1, uint64_t p2=0, const char* s=NULL)
: opcode(op), operand1(p1), operand2(p2), name(s) {}
uint8_t opcode;
uint64_t operand1;
uint64_t operand2;
const char* name;
};
static ld::Section _s_section;
};
template <typename A>
ld::Section WeakBindingInfoAtom<A>::_s_section("__LINKEDIT", "__weak_binding", ld::Section::typeLinkEdit, true);
template <typename A>
void WeakBindingInfoAtom<A>::encode() const
{
// sort by symbol, type, address
std::vector<OutputFile::BindingInfo>& info = this->_writer._weakBindingInfo;
if ( info.size() == 0 ) {
// short circuit if no weak binding needed
this->_encoded = true;
return;
}
std::sort(info.begin(), info.end(), WeakBindingSorter());
// convert to temp encoding that can be more easily optimized
std::vector<binding_tmp> mid;
mid.reserve(info.size());
uint64_t curSegStart = 0;
uint64_t curSegEnd = 0;
uint32_t curSegIndex = 0;
const char* symbolName = NULL;
uint8_t type = 0;
uint64_t address = (uint64_t)(-1);
int64_t addend = 0;
for (typename std::vector<OutputFile::BindingInfo>::const_iterator it = info.begin(); it != info.end(); ++it) {
if ( symbolName != it->_symbolName ) {
mid.push_back(binding_tmp(BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM, it->_flags, 0, it->_symbolName));
symbolName = it->_symbolName;
}
// non-weak symbols just have BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM
// weak symbols have SET_SEG, ADD_ADDR, SET_ADDED, DO_BIND
if ( it->_type != BIND_TYPE_OVERRIDE_OF_WEAKDEF_IN_DYLIB ) {
if ( type != it->_type ) {
mid.push_back(binding_tmp(BIND_OPCODE_SET_TYPE_IMM, it->_type));
type = it->_type;
}
if ( address != it->_address ) {
if ( (it->_address < curSegStart) || ( it->_address >= curSegEnd) ) {
if ( ! this->_writer.findSegment(this->_state, it->_address, &curSegStart, &curSegEnd, &curSegIndex) )
throw "binding address outside range of any segment";
mid.push_back(binding_tmp(BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB, curSegIndex, it->_address - curSegStart));
}
else {
mid.push_back(binding_tmp(BIND_OPCODE_ADD_ADDR_ULEB, it->_address-address));
}
address = it->_address;
}
if ( addend != it->_addend ) {
mid.push_back(binding_tmp(BIND_OPCODE_SET_ADDEND_SLEB, it->_addend));
addend = it->_addend;
}
mid.push_back(binding_tmp(BIND_OPCODE_DO_BIND, 0));
address += sizeof(pint_t);
}
}
mid.push_back(binding_tmp(BIND_OPCODE_DONE, 0));
// optimize phase 1, combine bind/add pairs
binding_tmp* dst = &mid[0];
for (const binding_tmp* src = &mid[0]; src->opcode != BIND_OPCODE_DONE; ++src) {
if ( (src->opcode == BIND_OPCODE_DO_BIND)
&& (src[1].opcode == BIND_OPCODE_ADD_ADDR_ULEB) ) {
dst->opcode = BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB;
dst->operand1 = src[1].operand1;
++src;
++dst;
}
else {
*dst++ = *src;
}