llvm-project/lld/lib/ReaderWriter/MachO/MachOLinkingContext.cpp

426 lines
11 KiB
C++

//===- lib/ReaderWriter/MachO/MachOLinkingContext.cpp ---------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "lld/ReaderWriter/MachOLinkingContext.h"
#include "ArchHandler.h"
#include "MachOPasses.h"
#include "lld/Core/PassManager.h"
#include "lld/ReaderWriter/Reader.h"
#include "lld/ReaderWriter/Writer.h"
#include "lld/Passes/LayoutPass.h"
#include "lld/Passes/RoundTripYAMLPass.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/MachO.h"
#include "llvm/Support/Path.h"
using lld::mach_o::ArchHandler;
using namespace llvm::MachO;
namespace lld {
bool MachOLinkingContext::parsePackedVersion(StringRef str, uint32_t &result) {
result = 0;
if (str.empty())
return false;
SmallVector<StringRef, 3> parts;
llvm::SplitString(str, parts, ".");
unsigned long long num;
if (llvm::getAsUnsignedInteger(parts[0], 10, num))
return true;
if (num > 65535)
return true;
result = num << 16;
if (parts.size() > 1) {
if (llvm::getAsUnsignedInteger(parts[1], 10, num))
return true;
if (num > 255)
return true;
result |= (num << 8);
}
if (parts.size() > 2) {
if (llvm::getAsUnsignedInteger(parts[2], 10, num))
return true;
if (num > 255)
return true;
result |= num;
}
return false;
}
MachOLinkingContext::ArchInfo MachOLinkingContext::_s_archInfos[] = {
{ "x86_64", arch_x86_64, true, CPU_TYPE_X86_64, CPU_SUBTYPE_X86_64_ALL },
{ "i386", arch_x86, true, CPU_TYPE_I386, CPU_SUBTYPE_X86_ALL },
{ "ppc", arch_ppc, false, CPU_TYPE_POWERPC, CPU_SUBTYPE_POWERPC_ALL },
{ "armv6", arch_armv6, true, CPU_TYPE_ARM, CPU_SUBTYPE_ARM_V6 },
{ "armv7", arch_armv7, true, CPU_TYPE_ARM, CPU_SUBTYPE_ARM_V7 },
{ "armv7s", arch_armv7s, true, CPU_TYPE_ARM, CPU_SUBTYPE_ARM_V7S },
{ "", arch_unknown,false, 0, 0 }
};
MachOLinkingContext::Arch
MachOLinkingContext::archFromCpuType(uint32_t cputype, uint32_t cpusubtype) {
for (ArchInfo *info = _s_archInfos; !info->archName.empty(); ++info) {
if ((info->cputype == cputype) && (info->cpusubtype == cpusubtype))
return info->arch;
}
return arch_unknown;
}
MachOLinkingContext::Arch
MachOLinkingContext::archFromName(StringRef archName) {
for (ArchInfo *info = _s_archInfos; !info->archName.empty(); ++info) {
if (info->archName.equals(archName))
return info->arch;
}
return arch_unknown;
}
StringRef MachOLinkingContext::nameFromArch(Arch arch) {
for (ArchInfo *info = _s_archInfos; !info->archName.empty(); ++info) {
if (info->arch == arch)
return info->archName;
}
return "<unknown>";
}
uint32_t MachOLinkingContext::cpuTypeFromArch(Arch arch) {
assert(arch != arch_unknown);
for (ArchInfo *info = _s_archInfos; !info->archName.empty(); ++info) {
if (info->arch == arch)
return info->cputype;
}
llvm_unreachable("Unknown arch type");
}
uint32_t MachOLinkingContext::cpuSubtypeFromArch(Arch arch) {
assert(arch != arch_unknown);
for (ArchInfo *info = _s_archInfos; !info->archName.empty(); ++info) {
if (info->arch == arch)
return info->cpusubtype;
}
llvm_unreachable("Unknown arch type");
}
MachOLinkingContext::MachOLinkingContext()
: _outputMachOType(MH_EXECUTE), _outputMachOTypeStatic(false),
_doNothing(false), _arch(arch_unknown), _os(OS::macOSX), _osMinVersion(0),
_pageZeroSize(0), _pageSize(4096), _compatibilityVersion(0),
_currentVersion(0), _deadStrippableDylib(false), _printAtoms(false),
_testingLibResolution(false), _archHandler(nullptr) {}
MachOLinkingContext::~MachOLinkingContext() {}
void MachOLinkingContext::configure(HeaderFileType type, Arch arch, OS os,
uint32_t minOSVersion) {
_outputMachOType = type;
_arch = arch;
_os = os;
_osMinVersion = minOSVersion;
switch (_outputMachOType) {
case llvm::MachO::MH_EXECUTE:
// If targeting newer OS, use _main
if (minOS("10.8", "6.0")) {
_entrySymbolName = "_main";
} else {
// If targeting older OS, use start (in crt1.o)
_entrySymbolName = "start";
}
// __PAGEZERO defaults to 4GB on 64-bit (except for PP64 which lld does not
// support) and 4KB on 32-bit.
if (is64Bit(_arch)) {
_pageZeroSize = 0x100000000;
} else {
_pageZeroSize = 0x1000;
}
break;
case llvm::MachO::MH_DYLIB:
_globalsAreDeadStripRoots = true;
break;
case llvm::MachO::MH_BUNDLE:
break;
case llvm::MachO::MH_OBJECT:
_printRemainingUndefines = false;
_allowRemainingUndefines = true;
default:
break;
}
}
uint32_t MachOLinkingContext::getCPUType() const {
return cpuTypeFromArch(_arch);
}
uint32_t MachOLinkingContext::getCPUSubType() const {
return cpuSubtypeFromArch(_arch);
}
bool MachOLinkingContext::is64Bit(Arch arch) {
for (ArchInfo *info = _s_archInfos; !info->archName.empty(); ++info) {
if (info->arch == arch) {
return (info->cputype & CPU_ARCH_ABI64);
}
}
// unknown archs are not 64-bit.
return false;
}
bool MachOLinkingContext::isHostEndian(Arch arch) {
assert(arch != arch_unknown);
for (ArchInfo *info = _s_archInfos; !info->archName.empty(); ++info) {
if (info->arch == arch) {
return (info->littleEndian == llvm::sys::IsLittleEndianHost);
}
}
llvm_unreachable("Unknown arch type");
}
bool MachOLinkingContext::isBigEndian(Arch arch) {
assert(arch != arch_unknown);
for (ArchInfo *info = _s_archInfos; !info->archName.empty(); ++info) {
if (info->arch == arch) {
return ! info->littleEndian;
}
}
llvm_unreachable("Unknown arch type");
}
bool MachOLinkingContext::is64Bit() const {
return is64Bit(_arch);
}
bool MachOLinkingContext::outputTypeHasEntry() const {
switch (_outputMachOType) {
case MH_EXECUTE:
case MH_DYLINKER:
case MH_PRELOAD:
return true;
default:
return false;
}
}
bool MachOLinkingContext::needsStubsPass() const {
switch (_outputMachOType) {
case MH_EXECUTE:
return !_outputMachOTypeStatic;
case MH_DYLIB:
case MH_BUNDLE:
return true;
default:
return false;
}
}
bool MachOLinkingContext::needsGOTPass() const {
// Only x86_64 uses GOT pass but not in -r mode.
if (_arch != arch_x86_64)
return false;
return (_outputMachOType != MH_OBJECT);
}
StringRef MachOLinkingContext::binderSymbolName() const {
return archHandler().stubInfo().binderSymbolName;
}
bool MachOLinkingContext::minOS(StringRef mac, StringRef iOS) const {
uint32_t parsedVersion;
switch (_os) {
case OS::macOSX:
if (parsePackedVersion(mac, parsedVersion))
return false;
return _osMinVersion >= parsedVersion;
case OS::iOS:
case OS::iOS_simulator:
if (parsePackedVersion(iOS, parsedVersion))
return false;
return _osMinVersion >= parsedVersion;
case OS::unknown:
break;
}
llvm_unreachable("target not configured for iOS or MacOSX");
}
bool MachOLinkingContext::addEntryPointLoadCommand() const {
if ((_outputMachOType == MH_EXECUTE) && !_outputMachOTypeStatic) {
return minOS("10.8", "6.0");
}
return false;
}
bool MachOLinkingContext::addUnixThreadLoadCommand() const {
switch (_outputMachOType) {
case MH_EXECUTE:
if (_outputMachOTypeStatic)
return true;
else
return !minOS("10.8", "6.0");
break;
case MH_DYLINKER:
case MH_PRELOAD:
return true;
default:
return false;
}
}
bool MachOLinkingContext::pathExists(StringRef path) const {
if (!testingLibResolution())
return llvm::sys::fs::exists(path.str());
// Otherwise, we're in test mode: only files explicitly provided on the
// command-line exist.
return _existingPaths.find(path) != _existingPaths.end();
}
void MachOLinkingContext::addModifiedSearchDir(
StringRef libPath, const StringRefVector &syslibRoots, bool isSystemPath) {
bool addedModifiedPath = false;
// Two cases to consider here:
// + If the last -syslibroot is "/", all of them are ignored (don't ask).
// + -syslibroot only applies to absolute paths.
if (!syslibRoots.empty() && syslibRoots.back() != "/" &&
llvm::sys::path::is_absolute(libPath)) {
for (auto syslibRoot : syslibRoots) {
SmallString<256> path(syslibRoot);
llvm::sys::path::append(path, libPath);
if (pathExists(path)) {
_searchDirs.push_back(path.str().copy(_allocator));
addedModifiedPath = true;
}
}
}
if (addedModifiedPath)
return;
// Finally, if only one -syslibroot is given, system paths which aren't in it
// get suppressed.
if (syslibRoots.size() != 1 || !isSystemPath) {
if (pathExists(libPath)) {
_searchDirs.push_back(libPath);
}
}
}
ErrorOr<StringRef>
MachOLinkingContext::searchDirForLibrary(StringRef path,
StringRef libName) const {
SmallString<256> fullPath;
if (libName.endswith(".o")) {
// A request ending in .o is special: just search for the file directly.
fullPath.assign(path);
llvm::sys::path::append(fullPath, libName);
if (pathExists(fullPath))
return fullPath.str().copy(_allocator);
return make_error_code(llvm::errc::no_such_file_or_directory);
}
// Search for dynamic library
fullPath.assign(path);
llvm::sys::path::append(fullPath, Twine("lib") + libName + ".dylib");
if (pathExists(fullPath))
return fullPath.str().copy(_allocator);
// If not, try for a static library
fullPath.assign(path);
llvm::sys::path::append(fullPath, Twine("lib") + libName + ".a");
if (pathExists(fullPath))
return fullPath.str().copy(_allocator);
return make_error_code(llvm::errc::no_such_file_or_directory);
}
ErrorOr<StringRef> MachOLinkingContext::searchLibrary(StringRef libName) const {
SmallString<256> path;
for (StringRef dir : searchDirs()) {
ErrorOr<StringRef> ec = searchDirForLibrary(dir, libName);
if (ec)
return ec;
}
return make_error_code(llvm::errc::no_such_file_or_directory);
}
bool MachOLinkingContext::validateImpl(raw_ostream &diagnostics) {
// TODO: if -arch not specified, look at arch of first .o file.
if (_currentVersion && _outputMachOType != MH_DYLIB) {
diagnostics << "error: -current_version can only be used with dylibs\n";
return false;
}
if (_compatibilityVersion && _outputMachOType != MH_DYLIB) {
diagnostics
<< "error: -compatibility_version can only be used with dylibs\n";
return false;
}
if (_deadStrippableDylib && _outputMachOType != MH_DYLIB) {
diagnostics
<< "error: -mark_dead_strippable_dylib can only be used with dylibs.\n";
return false;
}
if (!_bundleLoader.empty() && outputMachOType() != MH_BUNDLE) {
diagnostics
<< "error: -bundle_loader can only be used with Mach-O bundles\n";
return false;
}
return true;
}
void MachOLinkingContext::addPasses(PassManager &pm) {
pm.add(std::unique_ptr<Pass>(new LayoutPass(registry())));
if (needsStubsPass())
mach_o::addStubsPass(pm, *this);
if (needsGOTPass())
mach_o::addGOTPass(pm, *this);
}
Writer &MachOLinkingContext::writer() const {
if (!_writer)
_writer = createWriterMachO(*this);
return *_writer;
}
ArchHandler &MachOLinkingContext::archHandler() const {
if (!_archHandler)
_archHandler = ArchHandler::create(_arch);
return *_archHandler;
}
} // end namespace lld