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llvm/lld/COFF/Driver.cpp
Martin Storsjö 9c29291dfa [LLD] [COFF] Fix export directives in object files from -includeoptional 
When an object file contains an export directive, we normally do some
amount of deferred processing of them at the end of the linking
process. The -includeoptional option was handled after this, and
any object files (defining new exports) weren't handled.

Move the handling of the -includeoptional into the same late loop
which does the fixups for e.g. export directives.

Ideally, this would also be done for object files that are pulled
in by the wrap options, and for mingw autoimports, but those changes
require more modifications, to make them safe for potentially
being executed multiple times.

This fixes https://github.com/llvm/llvm-project/issues/57243.

Differential Revision: https://reviews.llvm.org/D132361

(cherry picked from commit af39e6f6fc905f3c067f022fb44136779d2f9c84)
2022-08-25 12:49:09 +02:00

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//===- Driver.cpp ---------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "Driver.h"
#include "COFFLinkerContext.h"
#include "Config.h"
#include "DebugTypes.h"
#include "ICF.h"
#include "InputFiles.h"
#include "MarkLive.h"
#include "MinGW.h"
#include "SymbolTable.h"
#include "Symbols.h"
#include "Writer.h"
#include "lld/Common/Args.h"
#include "lld/Common/Driver.h"
#include "lld/Common/Filesystem.h"
#include "lld/Common/Timer.h"
#include "lld/Common/Version.h"
#include "llvm/ADT/IntrusiveRefCntPtr.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/ADT/Triple.h"
#include "llvm/BinaryFormat/Magic.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/LTO/LTO.h"
#include "llvm/Object/ArchiveWriter.h"
#include "llvm/Object/COFFImportFile.h"
#include "llvm/Object/COFFModuleDefinition.h"
#include "llvm/Object/WindowsMachineFlag.h"
#include "llvm/Option/Arg.h"
#include "llvm/Option/ArgList.h"
#include "llvm/Option/Option.h"
#include "llvm/Support/BinaryStreamReader.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Parallel.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Process.h"
#include "llvm/Support/TarWriter.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/VirtualFileSystem.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/ToolDrivers/llvm-lib/LibDriver.h"
#include <algorithm>
#include <future>
#include <memory>
using namespace llvm;
using namespace llvm::object;
using namespace llvm::COFF;
using namespace llvm::sys;
namespace lld {
namespace coff {
std::unique_ptr<Configuration> config;
std::unique_ptr<LinkerDriver> driver;
bool link(ArrayRef<const char *> args, llvm::raw_ostream &stdoutOS,
llvm::raw_ostream &stderrOS, bool exitEarly, bool disableOutput) {
// This driver-specific context will be freed later by lldMain().
auto *ctx = new COFFLinkerContext;
ctx->e.initialize(stdoutOS, stderrOS, exitEarly, disableOutput);
ctx->e.logName = args::getFilenameWithoutExe(args[0]);
ctx->e.errorLimitExceededMsg = "too many errors emitted, stopping now"
" (use /errorlimit:0 to see all errors)";
config = std::make_unique<Configuration>();
driver = std::make_unique<LinkerDriver>(*ctx);
driver->linkerMain(args);
return errorCount() == 0;
}
// Parse options of the form "old;new".
static std::pair<StringRef, StringRef> getOldNewOptions(opt::InputArgList &args,
unsigned id) {
auto *arg = args.getLastArg(id);
if (!arg)
return {"", ""};
StringRef s = arg->getValue();
std::pair<StringRef, StringRef> ret = s.split(';');
if (ret.second.empty())
error(arg->getSpelling() + " expects 'old;new' format, but got " + s);
return ret;
}
// Drop directory components and replace extension with
// ".exe", ".dll" or ".sys".
static std::string getOutputPath(StringRef path) {
StringRef ext = ".exe";
if (config->dll)
ext = ".dll";
else if (config->driver)
ext = ".sys";
return (sys::path::stem(path) + ext).str();
}
// Returns true if S matches /crtend.?\.o$/.
static bool isCrtend(StringRef s) {
if (!s.endswith(".o"))
return false;
s = s.drop_back(2);
if (s.endswith("crtend"))
return true;
return !s.empty() && s.drop_back().endswith("crtend");
}
// ErrorOr is not default constructible, so it cannot be used as the type
// parameter of a future.
// FIXME: We could open the file in createFutureForFile and avoid needing to
// return an error here, but for the moment that would cost us a file descriptor
// (a limited resource on Windows) for the duration that the future is pending.
using MBErrPair = std::pair<std::unique_ptr<MemoryBuffer>, std::error_code>;
// Create a std::future that opens and maps a file using the best strategy for
// the host platform.
static std::future<MBErrPair> createFutureForFile(std::string path) {
#if _WIN64
// On Windows, file I/O is relatively slow so it is best to do this
// asynchronously. But 32-bit has issues with potentially launching tons
// of threads
auto strategy = std::launch::async;
#else
auto strategy = std::launch::deferred;
#endif
return std::async(strategy, [=]() {
auto mbOrErr = MemoryBuffer::getFile(path, /*IsText=*/false,
/*RequiresNullTerminator=*/false);
if (!mbOrErr)
return MBErrPair{nullptr, mbOrErr.getError()};
return MBErrPair{std::move(*mbOrErr), std::error_code()};
});
}
// Symbol names are mangled by prepending "_" on x86.
static StringRef mangle(StringRef sym) {
assert(config->machine != IMAGE_FILE_MACHINE_UNKNOWN);
if (config->machine == I386)
return saver().save("_" + sym);
return sym;
}
static llvm::Triple::ArchType getArch() {
switch (config->machine) {
case I386:
return llvm::Triple::ArchType::x86;
case AMD64:
return llvm::Triple::ArchType::x86_64;
case ARMNT:
return llvm::Triple::ArchType::arm;
case ARM64:
return llvm::Triple::ArchType::aarch64;
default:
return llvm::Triple::ArchType::UnknownArch;
}
}
bool LinkerDriver::findUnderscoreMangle(StringRef sym) {
Symbol *s = ctx.symtab.findMangle(mangle(sym));
return s && !isa<Undefined>(s);
}
MemoryBufferRef LinkerDriver::takeBuffer(std::unique_ptr<MemoryBuffer> mb) {
MemoryBufferRef mbref = *mb;
make<std::unique_ptr<MemoryBuffer>>(std::move(mb)); // take ownership
if (driver->tar)
driver->tar->append(relativeToRoot(mbref.getBufferIdentifier()),
mbref.getBuffer());
return mbref;
}
void LinkerDriver::addBuffer(std::unique_ptr<MemoryBuffer> mb,
bool wholeArchive, bool lazy) {
StringRef filename = mb->getBufferIdentifier();
MemoryBufferRef mbref = takeBuffer(std::move(mb));
filePaths.push_back(filename);
// File type is detected by contents, not by file extension.
switch (identify_magic(mbref.getBuffer())) {
case file_magic::windows_resource:
resources.push_back(mbref);
break;
case file_magic::archive:
if (wholeArchive) {
std::unique_ptr<Archive> file =
CHECK(Archive::create(mbref), filename + ": failed to parse archive");
Archive *archive = file.get();
make<std::unique_ptr<Archive>>(std::move(file)); // take ownership
int memberIndex = 0;
for (MemoryBufferRef m : getArchiveMembers(archive))
addArchiveBuffer(m, "<whole-archive>", filename, memberIndex++);
return;
}
ctx.symtab.addFile(make<ArchiveFile>(ctx, mbref));
break;
case file_magic::bitcode:
ctx.symtab.addFile(make<BitcodeFile>(ctx, mbref, "", 0, lazy));
break;
case file_magic::coff_object:
case file_magic::coff_import_library:
ctx.symtab.addFile(make<ObjFile>(ctx, mbref, lazy));
break;
case file_magic::pdb:
ctx.symtab.addFile(make<PDBInputFile>(ctx, mbref));
break;
case file_magic::coff_cl_gl_object:
error(filename + ": is not a native COFF file. Recompile without /GL");
break;
case file_magic::pecoff_executable:
if (config->mingw) {
ctx.symtab.addFile(make<DLLFile>(ctx, mbref));
break;
}
if (filename.endswith_insensitive(".dll")) {
error(filename + ": bad file type. Did you specify a DLL instead of an "
"import library?");
break;
}
LLVM_FALLTHROUGH;
default:
error(mbref.getBufferIdentifier() + ": unknown file type");
break;
}
}
void LinkerDriver::enqueuePath(StringRef path, bool wholeArchive, bool lazy) {
auto future = std::make_shared<std::future<MBErrPair>>(
createFutureForFile(std::string(path)));
std::string pathStr = std::string(path);
enqueueTask([=]() {
auto mbOrErr = future->get();
if (mbOrErr.second) {
std::string msg =
"could not open '" + pathStr + "': " + mbOrErr.second.message();
// Check if the filename is a typo for an option flag. OptTable thinks
// that all args that are not known options and that start with / are
// filenames, but e.g. `/nodefaultlibs` is more likely a typo for
// the option `/nodefaultlib` than a reference to a file in the root
// directory.
std::string nearest;
if (optTable.findNearest(pathStr, nearest) > 1)
error(msg);
else
error(msg + "; did you mean '" + nearest + "'");
} else
driver->addBuffer(std::move(mbOrErr.first), wholeArchive, lazy);
});
}
void LinkerDriver::addArchiveBuffer(MemoryBufferRef mb, StringRef symName,
StringRef parentName,
uint64_t offsetInArchive) {
file_magic magic = identify_magic(mb.getBuffer());
if (magic == file_magic::coff_import_library) {
InputFile *imp = make<ImportFile>(ctx, mb);
imp->parentName = parentName;
ctx.symtab.addFile(imp);
return;
}
InputFile *obj;
if (magic == file_magic::coff_object) {
obj = make<ObjFile>(ctx, mb);
} else if (magic == file_magic::bitcode) {
obj =
make<BitcodeFile>(ctx, mb, parentName, offsetInArchive, /*lazy=*/false);
} else {
error("unknown file type: " + mb.getBufferIdentifier());
return;
}
obj->parentName = parentName;
ctx.symtab.addFile(obj);
log("Loaded " + toString(obj) + " for " + symName);
}
void LinkerDriver::enqueueArchiveMember(const Archive::Child &c,
const Archive::Symbol &sym,
StringRef parentName) {
auto reportBufferError = [=](Error &&e, StringRef childName) {
fatal("could not get the buffer for the member defining symbol " +
toCOFFString(sym) + ": " + parentName + "(" + childName + "): " +
toString(std::move(e)));
};
if (!c.getParent()->isThin()) {
uint64_t offsetInArchive = c.getChildOffset();
Expected<MemoryBufferRef> mbOrErr = c.getMemoryBufferRef();
if (!mbOrErr)
reportBufferError(mbOrErr.takeError(), check(c.getFullName()));
MemoryBufferRef mb = mbOrErr.get();
enqueueTask([=]() {
driver->addArchiveBuffer(mb, toCOFFString(sym), parentName,
offsetInArchive);
});
return;
}
std::string childName = CHECK(
c.getFullName(),
"could not get the filename for the member defining symbol " +
toCOFFString(sym));
auto future = std::make_shared<std::future<MBErrPair>>(
createFutureForFile(childName));
enqueueTask([=]() {
auto mbOrErr = future->get();
if (mbOrErr.second)
reportBufferError(errorCodeToError(mbOrErr.second), childName);
// Pass empty string as archive name so that the original filename is
// used as the buffer identifier.
driver->addArchiveBuffer(takeBuffer(std::move(mbOrErr.first)),
toCOFFString(sym), "", /*OffsetInArchive=*/0);
});
}
static bool isDecorated(StringRef sym) {
return sym.startswith("@") || sym.contains("@@") || sym.startswith("?") ||
(!config->mingw && sym.contains('@'));
}
// Parses .drectve section contents and returns a list of files
// specified by /defaultlib.
void LinkerDriver::parseDirectives(InputFile *file) {
StringRef s = file->getDirectives();
if (s.empty())
return;
log("Directives: " + toString(file) + ": " + s);
ArgParser parser;
// .drectve is always tokenized using Windows shell rules.
// /EXPORT: option can appear too many times, processing in fastpath.
ParsedDirectives directives = parser.parseDirectives(s);
for (StringRef e : directives.exports) {
// If a common header file contains dllexported function
// declarations, many object files may end up with having the
// same /EXPORT options. In order to save cost of parsing them,
// we dedup them first.
if (!directivesExports.insert(e).second)
continue;
Export exp = parseExport(e);
if (config->machine == I386 && config->mingw) {
if (!isDecorated(exp.name))
exp.name = saver().save("_" + exp.name);
if (!exp.extName.empty() && !isDecorated(exp.extName))
exp.extName = saver().save("_" + exp.extName);
}
exp.directives = true;
config->exports.push_back(exp);
}
// Handle /include: in bulk.
for (StringRef inc : directives.includes)
addUndefined(inc);
// Handle /exclude-symbols: in bulk.
for (StringRef e : directives.excludes) {
SmallVector<StringRef, 2> vec;
e.split(vec, ',');
for (StringRef sym : vec)
excludedSymbols.insert(mangle(sym));
}
// https://docs.microsoft.com/en-us/cpp/preprocessor/comment-c-cpp?view=msvc-160
for (auto *arg : directives.args) {
switch (arg->getOption().getID()) {
case OPT_aligncomm:
parseAligncomm(arg->getValue());
break;
case OPT_alternatename:
parseAlternateName(arg->getValue());
break;
case OPT_defaultlib:
if (Optional<StringRef> path = findLib(arg->getValue()))
enqueuePath(*path, false, false);
break;
case OPT_entry:
config->entry = addUndefined(mangle(arg->getValue()));
break;
case OPT_failifmismatch:
checkFailIfMismatch(arg->getValue(), file);
break;
case OPT_incl:
addUndefined(arg->getValue());
break;
case OPT_manifestdependency:
config->manifestDependencies.insert(arg->getValue());
break;
case OPT_merge:
parseMerge(arg->getValue());
break;
case OPT_nodefaultlib:
config->noDefaultLibs.insert(doFindLib(arg->getValue()).lower());
break;
case OPT_section:
parseSection(arg->getValue());
break;
case OPT_stack:
parseNumbers(arg->getValue(), &config->stackReserve,
&config->stackCommit);
break;
case OPT_subsystem: {
bool gotVersion = false;
parseSubsystem(arg->getValue(), &config->subsystem,
&config->majorSubsystemVersion,
&config->minorSubsystemVersion, &gotVersion);
if (gotVersion) {
config->majorOSVersion = config->majorSubsystemVersion;
config->minorOSVersion = config->minorSubsystemVersion;
}
break;
}
// Only add flags here that link.exe accepts in
// `#pragma comment(linker, "/flag")`-generated sections.
case OPT_editandcontinue:
case OPT_guardsym:
case OPT_throwingnew:
break;
default:
error(arg->getSpelling() + " is not allowed in .drectve");
}
}
}
// Find file from search paths. You can omit ".obj", this function takes
// care of that. Note that the returned path is not guaranteed to exist.
StringRef LinkerDriver::doFindFile(StringRef filename) {
auto getFilename = [](StringRef filename) -> StringRef {
if (config->vfs)
if (auto statOrErr = config->vfs->status(filename))
return saver().save(statOrErr->getName());
return filename;
};
bool hasPathSep = (filename.find_first_of("/\\") != StringRef::npos);
if (hasPathSep)
return getFilename(filename);
bool hasExt = filename.contains('.');
for (StringRef dir : searchPaths) {
SmallString<128> path = dir;
sys::path::append(path, filename);
path = SmallString<128>{getFilename(path.str())};
if (sys::fs::exists(path.str()))
return saver().save(path.str());
if (!hasExt) {
path.append(".obj");
path = SmallString<128>{getFilename(path.str())};
if (sys::fs::exists(path.str()))
return saver().save(path.str());
}
}
return filename;
}
static Optional<sys::fs::UniqueID> getUniqueID(StringRef path) {
sys::fs::UniqueID ret;
if (sys::fs::getUniqueID(path, ret))
return None;
return ret;
}
// Resolves a file path. This never returns the same path
// (in that case, it returns None).
Optional<StringRef> LinkerDriver::findFile(StringRef filename) {
StringRef path = doFindFile(filename);
if (Optional<sys::fs::UniqueID> id = getUniqueID(path)) {
bool seen = !visitedFiles.insert(*id).second;
if (seen)
return None;
}
if (path.endswith_insensitive(".lib"))
visitedLibs.insert(std::string(sys::path::filename(path).lower()));
return path;
}
// MinGW specific. If an embedded directive specified to link to
// foo.lib, but it isn't found, try libfoo.a instead.
StringRef LinkerDriver::doFindLibMinGW(StringRef filename) {
if (filename.contains('/') || filename.contains('\\'))
return filename;
SmallString<128> s = filename;
sys::path::replace_extension(s, ".a");
StringRef libName = saver().save("lib" + s.str());
return doFindFile(libName);
}
// Find library file from search path.
StringRef LinkerDriver::doFindLib(StringRef filename) {
// Add ".lib" to Filename if that has no file extension.
bool hasExt = filename.contains('.');
if (!hasExt)
filename = saver().save(filename + ".lib");
StringRef ret = doFindFile(filename);
// For MinGW, if the find above didn't turn up anything, try
// looking for a MinGW formatted library name.
if (config->mingw && ret == filename)
return doFindLibMinGW(filename);
return ret;
}
// Resolves a library path. /nodefaultlib options are taken into
// consideration. This never returns the same path (in that case,
// it returns None).
Optional<StringRef> LinkerDriver::findLib(StringRef filename) {
if (config->noDefaultLibAll)
return None;
if (!visitedLibs.insert(filename.lower()).second)
return None;
StringRef path = doFindLib(filename);
if (config->noDefaultLibs.count(path.lower()))
return None;
if (Optional<sys::fs::UniqueID> id = getUniqueID(path))
if (!visitedFiles.insert(*id).second)
return None;
return path;
}
void LinkerDriver::detectWinSysRoot(const opt::InputArgList &Args) {
IntrusiveRefCntPtr<vfs::FileSystem> VFS = vfs::getRealFileSystem();
// Check the command line first, that's the user explicitly telling us what to
// use. Check the environment next, in case we're being invoked from a VS
// command prompt. Failing that, just try to find the newest Visual Studio
// version we can and use its default VC toolchain.
Optional<StringRef> VCToolsDir, VCToolsVersion, WinSysRoot;
if (auto *A = Args.getLastArg(OPT_vctoolsdir))
VCToolsDir = A->getValue();
if (auto *A = Args.getLastArg(OPT_vctoolsversion))
VCToolsVersion = A->getValue();
if (auto *A = Args.getLastArg(OPT_winsysroot))
WinSysRoot = A->getValue();
if (!findVCToolChainViaCommandLine(*VFS, VCToolsDir, VCToolsVersion,
WinSysRoot, vcToolChainPath, vsLayout) &&
(Args.hasArg(OPT_lldignoreenv) ||
!findVCToolChainViaEnvironment(*VFS, vcToolChainPath, vsLayout)) &&
!findVCToolChainViaSetupConfig(*VFS, vcToolChainPath, vsLayout) &&
!findVCToolChainViaRegistry(vcToolChainPath, vsLayout))
return;
// If the VC environment hasn't been configured (perhaps because the user did
// not run vcvarsall), try to build a consistent link environment. If the
// environment variable is set however, assume the user knows what they're
// doing. If the user passes /vctoolsdir or /winsdkdir, trust that over env
// vars.
if (const auto *A = Args.getLastArg(OPT_diasdkdir, OPT_winsysroot)) {
diaPath = A->getValue();
if (A->getOption().getID() == OPT_winsysroot)
path::append(diaPath, "DIA SDK");
}
useWinSysRootLibPath = Args.hasArg(OPT_lldignoreenv) ||
!Process::GetEnv("LIB") ||
Args.getLastArg(OPT_vctoolsdir, OPT_winsysroot);
if (Args.hasArg(OPT_lldignoreenv) || !Process::GetEnv("LIB") ||
Args.getLastArg(OPT_winsdkdir, OPT_winsysroot)) {
Optional<StringRef> WinSdkDir, WinSdkVersion;
if (auto *A = Args.getLastArg(OPT_winsdkdir))
WinSdkDir = A->getValue();
if (auto *A = Args.getLastArg(OPT_winsdkversion))
WinSdkVersion = A->getValue();
if (useUniversalCRT(vsLayout, vcToolChainPath, getArch(), *VFS)) {
std::string UniversalCRTSdkPath;
std::string UCRTVersion;
if (getUniversalCRTSdkDir(*VFS, WinSdkDir, WinSdkVersion, WinSysRoot,
UniversalCRTSdkPath, UCRTVersion)) {
universalCRTLibPath = UniversalCRTSdkPath;
path::append(universalCRTLibPath, "Lib", UCRTVersion, "ucrt");
}
}
std::string sdkPath;
std::string windowsSDKIncludeVersion;
std::string windowsSDKLibVersion;
if (getWindowsSDKDir(*VFS, WinSdkDir, WinSdkVersion, WinSysRoot, sdkPath,
sdkMajor, windowsSDKIncludeVersion,
windowsSDKLibVersion)) {
windowsSdkLibPath = sdkPath;
path::append(windowsSdkLibPath, "Lib");
if (sdkMajor >= 8)
path::append(windowsSdkLibPath, windowsSDKLibVersion, "um");
}
}
}
void LinkerDriver::addWinSysRootLibSearchPaths() {
if (!diaPath.empty()) {
// The DIA SDK always uses the legacy vc arch, even in new MSVC versions.
path::append(diaPath, "lib", archToLegacyVCArch(getArch()));
searchPaths.push_back(saver().save(diaPath.str()));
}
if (useWinSysRootLibPath) {
searchPaths.push_back(saver().save(getSubDirectoryPath(
SubDirectoryType::Lib, vsLayout, vcToolChainPath, getArch())));
searchPaths.push_back(saver().save(
getSubDirectoryPath(SubDirectoryType::Lib, vsLayout, vcToolChainPath,
getArch(), "atlmfc")));
}
if (!universalCRTLibPath.empty()) {
StringRef ArchName = archToWindowsSDKArch(getArch());
if (!ArchName.empty()) {
path::append(universalCRTLibPath, ArchName);
searchPaths.push_back(saver().save(universalCRTLibPath.str()));
}
}
if (!windowsSdkLibPath.empty()) {
std::string path;
if (appendArchToWindowsSDKLibPath(sdkMajor, windowsSdkLibPath, getArch(),
path))
searchPaths.push_back(saver().save(path));
}
}
// Parses LIB environment which contains a list of search paths.
void LinkerDriver::addLibSearchPaths() {
Optional<std::string> envOpt = Process::GetEnv("LIB");
if (!envOpt)
return;
StringRef env = saver().save(*envOpt);
while (!env.empty()) {
StringRef path;
std::tie(path, env) = env.split(';');
searchPaths.push_back(path);
}
}
Symbol *LinkerDriver::addUndefined(StringRef name) {
Symbol *b = ctx.symtab.addUndefined(name);
if (!b->isGCRoot) {
b->isGCRoot = true;
config->gcroot.push_back(b);
}
return b;
}
StringRef LinkerDriver::mangleMaybe(Symbol *s) {
// If the plain symbol name has already been resolved, do nothing.
Undefined *unmangled = dyn_cast<Undefined>(s);
if (!unmangled)
return "";
// Otherwise, see if a similar, mangled symbol exists in the symbol table.
Symbol *mangled = ctx.symtab.findMangle(unmangled->getName());
if (!mangled)
return "";
// If we find a similar mangled symbol, make this an alias to it and return
// its name.
log(unmangled->getName() + " aliased to " + mangled->getName());
unmangled->weakAlias = ctx.symtab.addUndefined(mangled->getName());
return mangled->getName();
}
// Windows specific -- find default entry point name.
//
// There are four different entry point functions for Windows executables,
// each of which corresponds to a user-defined "main" function. This function
// infers an entry point from a user-defined "main" function.
StringRef LinkerDriver::findDefaultEntry() {
assert(config->subsystem != IMAGE_SUBSYSTEM_UNKNOWN &&
"must handle /subsystem before calling this");
if (config->mingw)
return mangle(config->subsystem == IMAGE_SUBSYSTEM_WINDOWS_GUI
? "WinMainCRTStartup"
: "mainCRTStartup");
if (config->subsystem == IMAGE_SUBSYSTEM_WINDOWS_GUI) {
if (findUnderscoreMangle("wWinMain")) {
if (!findUnderscoreMangle("WinMain"))
return mangle("wWinMainCRTStartup");
warn("found both wWinMain and WinMain; using latter");
}
return mangle("WinMainCRTStartup");
}
if (findUnderscoreMangle("wmain")) {
if (!findUnderscoreMangle("main"))
return mangle("wmainCRTStartup");
warn("found both wmain and main; using latter");
}
return mangle("mainCRTStartup");
}
WindowsSubsystem LinkerDriver::inferSubsystem() {
if (config->dll)
return IMAGE_SUBSYSTEM_WINDOWS_GUI;
if (config->mingw)
return IMAGE_SUBSYSTEM_WINDOWS_CUI;
// Note that link.exe infers the subsystem from the presence of these
// functions even if /entry: or /nodefaultlib are passed which causes them
// to not be called.
bool haveMain = findUnderscoreMangle("main");
bool haveWMain = findUnderscoreMangle("wmain");
bool haveWinMain = findUnderscoreMangle("WinMain");
bool haveWWinMain = findUnderscoreMangle("wWinMain");
if (haveMain || haveWMain) {
if (haveWinMain || haveWWinMain) {
warn(std::string("found ") + (haveMain ? "main" : "wmain") + " and " +
(haveWinMain ? "WinMain" : "wWinMain") +
"; defaulting to /subsystem:console");
}
return IMAGE_SUBSYSTEM_WINDOWS_CUI;
}
if (haveWinMain || haveWWinMain)
return IMAGE_SUBSYSTEM_WINDOWS_GUI;
return IMAGE_SUBSYSTEM_UNKNOWN;
}
static uint64_t getDefaultImageBase() {
if (config->is64())
return config->dll ? 0x180000000 : 0x140000000;
return config->dll ? 0x10000000 : 0x400000;
}
static std::string rewritePath(StringRef s) {
if (fs::exists(s))
return relativeToRoot(s);
return std::string(s);
}
// Reconstructs command line arguments so that so that you can re-run
// the same command with the same inputs. This is for --reproduce.
static std::string createResponseFile(const opt::InputArgList &args,
ArrayRef<StringRef> filePaths,
ArrayRef<StringRef> searchPaths) {
SmallString<0> data;
raw_svector_ostream os(data);
for (auto *arg : args) {
switch (arg->getOption().getID()) {
case OPT_linkrepro:
case OPT_reproduce:
case OPT_INPUT:
case OPT_defaultlib:
case OPT_libpath:
case OPT_winsysroot:
break;
case OPT_call_graph_ordering_file:
case OPT_deffile:
case OPT_manifestinput:
case OPT_natvis:
os << arg->getSpelling() << quote(rewritePath(arg->getValue())) << '\n';
break;
case OPT_order: {
StringRef orderFile = arg->getValue();
orderFile.consume_front("@");
os << arg->getSpelling() << '@' << quote(rewritePath(orderFile)) << '\n';
break;
}
case OPT_pdbstream: {
const std::pair<StringRef, StringRef> nameFile =
StringRef(arg->getValue()).split("=");
os << arg->getSpelling() << nameFile.first << '='
<< quote(rewritePath(nameFile.second)) << '\n';
break;
}
case OPT_implib:
case OPT_manifestfile:
case OPT_pdb:
case OPT_pdbstripped:
case OPT_out:
os << arg->getSpelling() << sys::path::filename(arg->getValue()) << "\n";
break;
default:
os << toString(*arg) << "\n";
}
}
for (StringRef path : searchPaths) {
std::string relPath = relativeToRoot(path);
os << "/libpath:" << quote(relPath) << "\n";
}
for (StringRef path : filePaths)
os << quote(relativeToRoot(path)) << "\n";
return std::string(data.str());
}
enum class DebugKind {
Unknown,
None,
Full,
FastLink,
GHash,
NoGHash,
Dwarf,
Symtab
};
static DebugKind parseDebugKind(const opt::InputArgList &args) {
auto *a = args.getLastArg(OPT_debug, OPT_debug_opt);
if (!a)
return DebugKind::None;
if (a->getNumValues() == 0)
return DebugKind::Full;
DebugKind debug = StringSwitch<DebugKind>(a->getValue())
.CaseLower("none", DebugKind::None)
.CaseLower("full", DebugKind::Full)
.CaseLower("fastlink", DebugKind::FastLink)
// LLD extensions
.CaseLower("ghash", DebugKind::GHash)
.CaseLower("noghash", DebugKind::NoGHash)
.CaseLower("dwarf", DebugKind::Dwarf)
.CaseLower("symtab", DebugKind::Symtab)
.Default(DebugKind::Unknown);
if (debug == DebugKind::FastLink) {
warn("/debug:fastlink unsupported; using /debug:full");
return DebugKind::Full;
}
if (debug == DebugKind::Unknown) {
error("/debug: unknown option: " + Twine(a->getValue()));
return DebugKind::None;
}
return debug;
}
static unsigned parseDebugTypes(const opt::InputArgList &args) {
unsigned debugTypes = static_cast<unsigned>(DebugType::None);
if (auto *a = args.getLastArg(OPT_debugtype)) {
SmallVector<StringRef, 3> types;
StringRef(a->getValue())
.split(types, ',', /*MaxSplit=*/-1, /*KeepEmpty=*/false);
for (StringRef type : types) {
unsigned v = StringSwitch<unsigned>(type.lower())
.Case("cv", static_cast<unsigned>(DebugType::CV))
.Case("pdata", static_cast<unsigned>(DebugType::PData))
.Case("fixup", static_cast<unsigned>(DebugType::Fixup))
.Default(0);
if (v == 0) {
warn("/debugtype: unknown option '" + type + "'");
continue;
}
debugTypes |= v;
}
return debugTypes;
}
// Default debug types
debugTypes = static_cast<unsigned>(DebugType::CV);
if (args.hasArg(OPT_driver))
debugTypes |= static_cast<unsigned>(DebugType::PData);
if (args.hasArg(OPT_profile))
debugTypes |= static_cast<unsigned>(DebugType::Fixup);
return debugTypes;
}
static std::string getMapFile(const opt::InputArgList &args,
opt::OptSpecifier os, opt::OptSpecifier osFile) {
auto *arg = args.getLastArg(os, osFile);
if (!arg)
return "";
if (arg->getOption().getID() == osFile.getID())
return arg->getValue();
assert(arg->getOption().getID() == os.getID());
StringRef outFile = config->outputFile;
return (outFile.substr(0, outFile.rfind('.')) + ".map").str();
}
static std::string getImplibPath() {
if (!config->implib.empty())
return std::string(config->implib);
SmallString<128> out = StringRef(config->outputFile);
sys::path::replace_extension(out, ".lib");
return std::string(out.str());
}
// The import name is calculated as follows:
//
// | LIBRARY w/ ext | LIBRARY w/o ext | no LIBRARY
// -----+----------------+---------------------+------------------
// LINK | {value} | {value}.{.dll/.exe} | {output name}
// LIB | {value} | {value}.dll | {output name}.dll
//
static std::string getImportName(bool asLib) {
SmallString<128> out;
if (config->importName.empty()) {
out.assign(sys::path::filename(config->outputFile));
if (asLib)
sys::path::replace_extension(out, ".dll");
} else {
out.assign(config->importName);
if (!sys::path::has_extension(out))
sys::path::replace_extension(out,
(config->dll || asLib) ? ".dll" : ".exe");
}
return std::string(out.str());
}
static void createImportLibrary(bool asLib) {
std::vector<COFFShortExport> exports;
for (Export &e1 : config->exports) {
COFFShortExport e2;
e2.Name = std::string(e1.name);
e2.SymbolName = std::string(e1.symbolName);
e2.ExtName = std::string(e1.extName);
e2.AliasTarget = std::string(e1.aliasTarget);
e2.Ordinal = e1.ordinal;
e2.Noname = e1.noname;
e2.Data = e1.data;
e2.Private = e1.isPrivate;
e2.Constant = e1.constant;
exports.push_back(e2);
}
std::string libName = getImportName(asLib);
std::string path = getImplibPath();
if (!config->incremental) {
checkError(writeImportLibrary(libName, path, exports, config->machine,
config->mingw));
return;
}
// If the import library already exists, replace it only if the contents
// have changed.
ErrorOr<std::unique_ptr<MemoryBuffer>> oldBuf = MemoryBuffer::getFile(
path, /*IsText=*/false, /*RequiresNullTerminator=*/false);
if (!oldBuf) {
checkError(writeImportLibrary(libName, path, exports, config->machine,
config->mingw));
return;
}
SmallString<128> tmpName;
if (std::error_code ec =
sys::fs::createUniqueFile(path + ".tmp-%%%%%%%%.lib", tmpName))
fatal("cannot create temporary file for import library " + path + ": " +
ec.message());
if (Error e = writeImportLibrary(libName, tmpName, exports, config->machine,
config->mingw)) {
checkError(std::move(e));
return;
}
std::unique_ptr<MemoryBuffer> newBuf = check(MemoryBuffer::getFile(
tmpName, /*IsText=*/false, /*RequiresNullTerminator=*/false));
if ((*oldBuf)->getBuffer() != newBuf->getBuffer()) {
oldBuf->reset();
checkError(errorCodeToError(sys::fs::rename(tmpName, path)));
} else {
sys::fs::remove(tmpName);
}
}
static void parseModuleDefs(StringRef path) {
std::unique_ptr<MemoryBuffer> mb =
CHECK(MemoryBuffer::getFile(path, /*IsText=*/false,
/*RequiresNullTerminator=*/false,
/*IsVolatile=*/true),
"could not open " + path);
COFFModuleDefinition m = check(parseCOFFModuleDefinition(
mb->getMemBufferRef(), config->machine, config->mingw));
// Include in /reproduce: output if applicable.
driver->takeBuffer(std::move(mb));
if (config->outputFile.empty())
config->outputFile = std::string(saver().save(m.OutputFile));
config->importName = std::string(saver().save(m.ImportName));
if (m.ImageBase)
config->imageBase = m.ImageBase;
if (m.StackReserve)
config->stackReserve = m.StackReserve;
if (m.StackCommit)
config->stackCommit = m.StackCommit;
if (m.HeapReserve)
config->heapReserve = m.HeapReserve;
if (m.HeapCommit)
config->heapCommit = m.HeapCommit;
if (m.MajorImageVersion)
config->majorImageVersion = m.MajorImageVersion;
if (m.MinorImageVersion)
config->minorImageVersion = m.MinorImageVersion;
if (m.MajorOSVersion)
config->majorOSVersion = m.MajorOSVersion;
if (m.MinorOSVersion)
config->minorOSVersion = m.MinorOSVersion;
for (COFFShortExport e1 : m.Exports) {
Export e2;
// In simple cases, only Name is set. Renamed exports are parsed
// and set as "ExtName = Name". If Name has the form "OtherDll.Func",
// it shouldn't be a normal exported function but a forward to another
// DLL instead. This is supported by both MS and GNU linkers.
if (!e1.ExtName.empty() && e1.ExtName != e1.Name &&
StringRef(e1.Name).contains('.')) {
e2.name = saver().save(e1.ExtName);
e2.forwardTo = saver().save(e1.Name);
config->exports.push_back(e2);
continue;
}
e2.name = saver().save(e1.Name);
e2.extName = saver().save(e1.ExtName);
e2.aliasTarget = saver().save(e1.AliasTarget);
e2.ordinal = e1.Ordinal;
e2.noname = e1.Noname;
e2.data = e1.Data;
e2.isPrivate = e1.Private;
e2.constant = e1.Constant;
config->exports.push_back(e2);
}
}
void LinkerDriver::enqueueTask(std::function<void()> task) {
taskQueue.push_back(std::move(task));
}
bool LinkerDriver::run() {
ScopedTimer t(ctx.inputFileTimer);
bool didWork = !taskQueue.empty();
while (!taskQueue.empty()) {
taskQueue.front()();
taskQueue.pop_front();
}
return didWork;
}
// Parse an /order file. If an option is given, the linker places
// COMDAT sections in the same order as their names appear in the
// given file.
static void parseOrderFile(COFFLinkerContext &ctx, StringRef arg) {
// For some reason, the MSVC linker requires a filename to be
// preceded by "@".
if (!arg.startswith("@")) {
error("malformed /order option: '@' missing");
return;
}
// Get a list of all comdat sections for error checking.
DenseSet<StringRef> set;
for (Chunk *c : ctx.symtab.getChunks())
if (auto *sec = dyn_cast<SectionChunk>(c))
if (sec->sym)
set.insert(sec->sym->getName());
// Open a file.
StringRef path = arg.substr(1);
std::unique_ptr<MemoryBuffer> mb =
CHECK(MemoryBuffer::getFile(path, /*IsText=*/false,
/*RequiresNullTerminator=*/false,
/*IsVolatile=*/true),
"could not open " + path);
// Parse a file. An order file contains one symbol per line.
// All symbols that were not present in a given order file are
// considered to have the lowest priority 0 and are placed at
// end of an output section.
for (StringRef arg : args::getLines(mb->getMemBufferRef())) {
std::string s(arg);
if (config->machine == I386 && !isDecorated(s))
s = "_" + s;
if (set.count(s) == 0) {
if (config->warnMissingOrderSymbol)
warn("/order:" + arg + ": missing symbol: " + s + " [LNK4037]");
}
else
config->order[s] = INT_MIN + config->order.size();
}
// Include in /reproduce: output if applicable.
driver->takeBuffer(std::move(mb));
}
static void parseCallGraphFile(COFFLinkerContext &ctx, StringRef path) {
std::unique_ptr<MemoryBuffer> mb =
CHECK(MemoryBuffer::getFile(path, /*IsText=*/false,
/*RequiresNullTerminator=*/false,
/*IsVolatile=*/true),
"could not open " + path);
// Build a map from symbol name to section.
DenseMap<StringRef, Symbol *> map;
for (ObjFile *file : ctx.objFileInstances)
for (Symbol *sym : file->getSymbols())
if (sym)
map[sym->getName()] = sym;
auto findSection = [&](StringRef name) -> SectionChunk * {
Symbol *sym = map.lookup(name);
if (!sym) {
if (config->warnMissingOrderSymbol)
warn(path + ": no such symbol: " + name);
return nullptr;
}
if (DefinedCOFF *dr = dyn_cast_or_null<DefinedCOFF>(sym))
return dyn_cast_or_null<SectionChunk>(dr->getChunk());
return nullptr;
};
for (StringRef line : args::getLines(*mb)) {
SmallVector<StringRef, 3> fields;
line.split(fields, ' ');
uint64_t count;
if (fields.size() != 3 || !to_integer(fields[2], count)) {
error(path + ": parse error");
return;
}
if (SectionChunk *from = findSection(fields[0]))
if (SectionChunk *to = findSection(fields[1]))
config->callGraphProfile[{from, to}] += count;
}
// Include in /reproduce: output if applicable.
driver->takeBuffer(std::move(mb));
}
static void readCallGraphsFromObjectFiles(COFFLinkerContext &ctx) {
for (ObjFile *obj : ctx.objFileInstances) {
if (obj->callgraphSec) {
ArrayRef<uint8_t> contents;
cantFail(
obj->getCOFFObj()->getSectionContents(obj->callgraphSec, contents));
BinaryStreamReader reader(contents, support::little);
while (!reader.empty()) {
uint32_t fromIndex, toIndex;
uint64_t count;
if (Error err = reader.readInteger(fromIndex))
fatal(toString(obj) + ": Expected 32-bit integer");
if (Error err = reader.readInteger(toIndex))
fatal(toString(obj) + ": Expected 32-bit integer");
if (Error err = reader.readInteger(count))
fatal(toString(obj) + ": Expected 64-bit integer");
auto *fromSym = dyn_cast_or_null<Defined>(obj->getSymbol(fromIndex));
auto *toSym = dyn_cast_or_null<Defined>(obj->getSymbol(toIndex));
if (!fromSym || !toSym)
continue;
auto *from = dyn_cast_or_null<SectionChunk>(fromSym->getChunk());
auto *to = dyn_cast_or_null<SectionChunk>(toSym->getChunk());
if (from && to)
config->callGraphProfile[{from, to}] += count;
}
}
}
}
static void markAddrsig(Symbol *s) {
if (auto *d = dyn_cast_or_null<Defined>(s))
if (SectionChunk *c = dyn_cast_or_null<SectionChunk>(d->getChunk()))
c->keepUnique = true;
}
static void findKeepUniqueSections(COFFLinkerContext &ctx) {
// Exported symbols could be address-significant in other executables or DSOs,
// so we conservatively mark them as address-significant.
for (Export &r : config->exports)
markAddrsig(r.sym);
// Visit the address-significance table in each object file and mark each
// referenced symbol as address-significant.
for (ObjFile *obj : ctx.objFileInstances) {
ArrayRef<Symbol *> syms = obj->getSymbols();
if (obj->addrsigSec) {
ArrayRef<uint8_t> contents;
cantFail(
obj->getCOFFObj()->getSectionContents(obj->addrsigSec, contents));
const uint8_t *cur = contents.begin();
while (cur != contents.end()) {
unsigned size;
const char *err;
uint64_t symIndex = decodeULEB128(cur, &size, contents.end(), &err);
if (err)
fatal(toString(obj) + ": could not decode addrsig section: " + err);
if (symIndex >= syms.size())
fatal(toString(obj) + ": invalid symbol index in addrsig section");
markAddrsig(syms[symIndex]);
cur += size;
}
} else {
// If an object file does not have an address-significance table,
// conservatively mark all of its symbols as address-significant.
for (Symbol *s : syms)
markAddrsig(s);
}
}
}
// link.exe replaces each %foo% in altPath with the contents of environment
// variable foo, and adds the two magic env vars _PDB (expands to the basename
// of pdb's output path) and _EXT (expands to the extension of the output
// binary).
// lld only supports %_PDB% and %_EXT% and warns on references to all other env
// vars.
static void parsePDBAltPath(StringRef altPath) {
SmallString<128> buf;
StringRef pdbBasename =
sys::path::filename(config->pdbPath, sys::path::Style::windows);
StringRef binaryExtension =
sys::path::extension(config->outputFile, sys::path::Style::windows);
if (!binaryExtension.empty())
binaryExtension = binaryExtension.substr(1); // %_EXT% does not include '.'.
// Invariant:
// +--------- cursor ('a...' might be the empty string).
// | +----- firstMark
// | | +- secondMark
// v v v
// a...%...%...
size_t cursor = 0;
while (cursor < altPath.size()) {
size_t firstMark, secondMark;
if ((firstMark = altPath.find('%', cursor)) == StringRef::npos ||
(secondMark = altPath.find('%', firstMark + 1)) == StringRef::npos) {
// Didn't find another full fragment, treat rest of string as literal.
buf.append(altPath.substr(cursor));
break;
}
// Found a full fragment. Append text in front of first %, and interpret
// text between first and second % as variable name.
buf.append(altPath.substr(cursor, firstMark - cursor));
StringRef var = altPath.substr(firstMark, secondMark - firstMark + 1);
if (var.equals_insensitive("%_pdb%"))
buf.append(pdbBasename);
else if (var.equals_insensitive("%_ext%"))
buf.append(binaryExtension);
else {
warn("only %_PDB% and %_EXT% supported in /pdbaltpath:, keeping " +
var + " as literal");
buf.append(var);
}
cursor = secondMark + 1;
}
config->pdbAltPath = buf;
}
/// Convert resource files and potentially merge input resource object
/// trees into one resource tree.
/// Call after ObjFile::Instances is complete.
void LinkerDriver::convertResources() {
std::vector<ObjFile *> resourceObjFiles;
for (ObjFile *f : ctx.objFileInstances) {
if (f->isResourceObjFile())
resourceObjFiles.push_back(f);
}
if (!config->mingw &&
(resourceObjFiles.size() > 1 ||
(resourceObjFiles.size() == 1 && !resources.empty()))) {
error((!resources.empty() ? "internal .obj file created from .res files"
: toString(resourceObjFiles[1])) +
": more than one resource obj file not allowed, already got " +
toString(resourceObjFiles.front()));
return;
}
if (resources.empty() && resourceObjFiles.size() <= 1) {
// No resources to convert, and max one resource object file in
// the input. Keep that preconverted resource section as is.
for (ObjFile *f : resourceObjFiles)
f->includeResourceChunks();
return;
}
ObjFile *f =
make<ObjFile>(ctx, convertResToCOFF(resources, resourceObjFiles));
ctx.symtab.addFile(f);
f->includeResourceChunks();
}
// In MinGW, if no symbols are chosen to be exported, then all symbols are
// automatically exported by default. This behavior can be forced by the
// -export-all-symbols option, so that it happens even when exports are
// explicitly specified. The automatic behavior can be disabled using the
// -exclude-all-symbols option, so that lld-link behaves like link.exe rather
// than MinGW in the case that nothing is explicitly exported.
void LinkerDriver::maybeExportMinGWSymbols(const opt::InputArgList &args) {
if (!args.hasArg(OPT_export_all_symbols)) {
if (!config->dll)
return;
if (!config->exports.empty())
return;
if (args.hasArg(OPT_exclude_all_symbols))
return;
}
AutoExporter exporter(excludedSymbols);
for (auto *arg : args.filtered(OPT_wholearchive_file))
if (Optional<StringRef> path = doFindFile(arg->getValue()))
exporter.addWholeArchive(*path);
for (auto *arg : args.filtered(OPT_exclude_symbols)) {
SmallVector<StringRef, 2> vec;
StringRef(arg->getValue()).split(vec, ',');
for (StringRef sym : vec)
exporter.addExcludedSymbol(mangle(sym));
}
ctx.symtab.forEachSymbol([&](Symbol *s) {
auto *def = dyn_cast<Defined>(s);
if (!exporter.shouldExport(ctx, def))
return;
if (!def->isGCRoot) {
def->isGCRoot = true;
config->gcroot.push_back(def);
}
Export e;
e.name = def->getName();
e.sym = def;
if (Chunk *c = def->getChunk())
if (!(c->getOutputCharacteristics() & IMAGE_SCN_MEM_EXECUTE))
e.data = true;
s->isUsedInRegularObj = true;
config->exports.push_back(e);
});
}
// lld has a feature to create a tar file containing all input files as well as
// all command line options, so that other people can run lld again with exactly
// the same inputs. This feature is accessible via /linkrepro and /reproduce.
//
// /linkrepro and /reproduce are very similar, but /linkrepro takes a directory
// name while /reproduce takes a full path. We have /linkrepro for compatibility
// with Microsoft link.exe.
Optional<std::string> getReproduceFile(const opt::InputArgList &args) {
if (auto *arg = args.getLastArg(OPT_reproduce))
return std::string(arg->getValue());
if (auto *arg = args.getLastArg(OPT_linkrepro)) {
SmallString<64> path = StringRef(arg->getValue());
sys::path::append(path, "repro.tar");
return std::string(path);
}
// This is intentionally not guarded by OPT_lldignoreenv since writing
// a repro tar file doesn't affect the main output.
if (auto *path = getenv("LLD_REPRODUCE"))
return std::string(path);
return None;
}
static std::unique_ptr<llvm::vfs::FileSystem>
getVFS(const opt::InputArgList &args) {
using namespace llvm::vfs;
const opt::Arg *arg = args.getLastArg(OPT_vfsoverlay);
if (!arg)
return nullptr;
auto bufOrErr = llvm::MemoryBuffer::getFile(arg->getValue());
if (!bufOrErr) {
checkError(errorCodeToError(bufOrErr.getError()));
return nullptr;
}
if (auto ret = vfs::getVFSFromYAML(std::move(*bufOrErr), /*DiagHandler*/ nullptr,
arg->getValue()))
return ret;
error("Invalid vfs overlay");
return nullptr;
}
void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
ScopedTimer rootTimer(ctx.rootTimer);
// Needed for LTO.
InitializeAllTargetInfos();
InitializeAllTargets();
InitializeAllTargetMCs();
InitializeAllAsmParsers();
InitializeAllAsmPrinters();
// If the first command line argument is "/lib", link.exe acts like lib.exe.
// We call our own implementation of lib.exe that understands bitcode files.
if (argsArr.size() > 1 &&
(StringRef(argsArr[1]).equals_insensitive("/lib") ||
StringRef(argsArr[1]).equals_insensitive("-lib"))) {
if (llvm::libDriverMain(argsArr.slice(1)) != 0)
fatal("lib failed");
return;
}
// Parse command line options.
ArgParser parser;
opt::InputArgList args = parser.parse(argsArr);
// Parse and evaluate -mllvm options.
std::vector<const char *> v;
v.push_back("lld-link (LLVM option parsing)");
for (auto *arg : args.filtered(OPT_mllvm))
v.push_back(arg->getValue());
cl::ResetAllOptionOccurrences();
cl::ParseCommandLineOptions(v.size(), v.data());
// Handle /errorlimit early, because error() depends on it.
if (auto *arg = args.getLastArg(OPT_errorlimit)) {
int n = 20;
StringRef s = arg->getValue();
if (s.getAsInteger(10, n))
error(arg->getSpelling() + " number expected, but got " + s);
errorHandler().errorLimit = n;
}
config->vfs = getVFS(args);
// Handle /help
if (args.hasArg(OPT_help)) {
printHelp(argsArr[0]);
return;
}
// /threads: takes a positive integer and provides the default value for
// /opt:lldltojobs=.
if (auto *arg = args.getLastArg(OPT_threads)) {
StringRef v(arg->getValue());
unsigned threads = 0;
if (!llvm::to_integer(v, threads, 0) || threads == 0)
error(arg->getSpelling() + ": expected a positive integer, but got '" +
arg->getValue() + "'");
parallel::strategy = hardware_concurrency(threads);
config->thinLTOJobs = v.str();
}
if (args.hasArg(OPT_show_timing))
config->showTiming = true;
config->showSummary = args.hasArg(OPT_summary);
// Handle --version, which is an lld extension. This option is a bit odd
// because it doesn't start with "/", but we deliberately chose "--" to
// avoid conflict with /version and for compatibility with clang-cl.
if (args.hasArg(OPT_dash_dash_version)) {
message(getLLDVersion());
return;
}
// Handle /lldmingw early, since it can potentially affect how other
// options are handled.
config->mingw = args.hasArg(OPT_lldmingw);
// Handle /linkrepro and /reproduce.
if (Optional<std::string> path = getReproduceFile(args)) {
Expected<std::unique_ptr<TarWriter>> errOrWriter =
TarWriter::create(*path, sys::path::stem(*path));
if (errOrWriter) {
tar = std::move(*errOrWriter);
} else {
error("/linkrepro: failed to open " + *path + ": " +
toString(errOrWriter.takeError()));
}
}
if (!args.hasArg(OPT_INPUT, OPT_wholearchive_file)) {
if (args.hasArg(OPT_deffile))
config->noEntry = true;
else
fatal("no input files");
}
// Construct search path list.
searchPaths.push_back("");
for (auto *arg : args.filtered(OPT_libpath))
searchPaths.push_back(arg->getValue());
detectWinSysRoot(args);
if (!args.hasArg(OPT_lldignoreenv) && !args.hasArg(OPT_winsysroot))
addLibSearchPaths();
// Handle /ignore
for (auto *arg : args.filtered(OPT_ignore)) {
SmallVector<StringRef, 8> vec;
StringRef(arg->getValue()).split(vec, ',');
for (StringRef s : vec) {
if (s == "4037")
config->warnMissingOrderSymbol = false;
else if (s == "4099")
config->warnDebugInfoUnusable = false;
else if (s == "4217")
config->warnLocallyDefinedImported = false;
else if (s == "longsections")
config->warnLongSectionNames = false;
// Other warning numbers are ignored.
}
}
// Handle /out
if (auto *arg = args.getLastArg(OPT_out))
config->outputFile = arg->getValue();
// Handle /verbose
if (args.hasArg(OPT_verbose))
config->verbose = true;
errorHandler().verbose = config->verbose;
// Handle /force or /force:unresolved
if (args.hasArg(OPT_force, OPT_force_unresolved))
config->forceUnresolved = true;
// Handle /force or /force:multiple
if (args.hasArg(OPT_force, OPT_force_multiple))
config->forceMultiple = true;
// Handle /force or /force:multipleres
if (args.hasArg(OPT_force, OPT_force_multipleres))
config->forceMultipleRes = true;
// Handle /debug
DebugKind debug = parseDebugKind(args);
if (debug == DebugKind::Full || debug == DebugKind::Dwarf ||
debug == DebugKind::GHash || debug == DebugKind::NoGHash) {
config->debug = true;
config->incremental = true;
}
// Handle /demangle
config->demangle = args.hasFlag(OPT_demangle, OPT_demangle_no, true);
// Handle /debugtype
config->debugTypes = parseDebugTypes(args);
// Handle /driver[:uponly|:wdm].
config->driverUponly = args.hasArg(OPT_driver_uponly) ||
args.hasArg(OPT_driver_uponly_wdm) ||
args.hasArg(OPT_driver_wdm_uponly);
config->driverWdm = args.hasArg(OPT_driver_wdm) ||
args.hasArg(OPT_driver_uponly_wdm) ||
args.hasArg(OPT_driver_wdm_uponly);
config->driver =
config->driverUponly || config->driverWdm || args.hasArg(OPT_driver);
// Handle /pdb
bool shouldCreatePDB =
(debug == DebugKind::Full || debug == DebugKind::GHash ||
debug == DebugKind::NoGHash);
if (shouldCreatePDB) {
if (auto *arg = args.getLastArg(OPT_pdb))
config->pdbPath = arg->getValue();
if (auto *arg = args.getLastArg(OPT_pdbaltpath))
config->pdbAltPath = arg->getValue();
if (auto *arg = args.getLastArg(OPT_pdbpagesize))
parsePDBPageSize(arg->getValue());
if (args.hasArg(OPT_natvis))
config->natvisFiles = args.getAllArgValues(OPT_natvis);
if (args.hasArg(OPT_pdbstream)) {
for (const StringRef value : args.getAllArgValues(OPT_pdbstream)) {
const std::pair<StringRef, StringRef> nameFile = value.split("=");
const StringRef name = nameFile.first;
const std::string file = nameFile.second.str();
config->namedStreams[name] = file;
}
}
if (auto *arg = args.getLastArg(OPT_pdb_source_path))
config->pdbSourcePath = arg->getValue();
}
// Handle /pdbstripped
if (args.hasArg(OPT_pdbstripped))
warn("ignoring /pdbstripped flag, it is not yet supported");
// Handle /noentry
if (args.hasArg(OPT_noentry)) {
if (args.hasArg(OPT_dll))
config->noEntry = true;
else
error("/noentry must be specified with /dll");
}
// Handle /dll
if (args.hasArg(OPT_dll)) {
config->dll = true;
config->manifestID = 2;
}
// Handle /dynamicbase and /fixed. We can't use hasFlag for /dynamicbase
// because we need to explicitly check whether that option or its inverse was
// present in the argument list in order to handle /fixed.
auto *dynamicBaseArg = args.getLastArg(OPT_dynamicbase, OPT_dynamicbase_no);
if (dynamicBaseArg &&
dynamicBaseArg->getOption().getID() == OPT_dynamicbase_no)
config->dynamicBase = false;
// MSDN claims "/FIXED:NO is the default setting for a DLL, and /FIXED is the
// default setting for any other project type.", but link.exe defaults to
// /FIXED:NO for exe outputs as well. Match behavior, not docs.
bool fixed = args.hasFlag(OPT_fixed, OPT_fixed_no, false);
if (fixed) {
if (dynamicBaseArg &&
dynamicBaseArg->getOption().getID() == OPT_dynamicbase) {
error("/fixed must not be specified with /dynamicbase");
} else {
config->relocatable = false;
config->dynamicBase = false;
}
}
// Handle /appcontainer
config->appContainer =
args.hasFlag(OPT_appcontainer, OPT_appcontainer_no, false);
// Handle /machine
if (auto *arg = args.getLastArg(OPT_machine)) {
config->machine = getMachineType(arg->getValue());
if (config->machine == IMAGE_FILE_MACHINE_UNKNOWN)
fatal(Twine("unknown /machine argument: ") + arg->getValue());
addWinSysRootLibSearchPaths();
}
// Handle /nodefaultlib:<filename>
for (auto *arg : args.filtered(OPT_nodefaultlib))
config->noDefaultLibs.insert(doFindLib(arg->getValue()).lower());
// Handle /nodefaultlib
if (args.hasArg(OPT_nodefaultlib_all))
config->noDefaultLibAll = true;
// Handle /base
if (auto *arg = args.getLastArg(OPT_base))
parseNumbers(arg->getValue(), &config->imageBase);
// Handle /filealign
if (auto *arg = args.getLastArg(OPT_filealign)) {
parseNumbers(arg->getValue(), &config->fileAlign);
if (!isPowerOf2_64(config->fileAlign))
error("/filealign: not a power of two: " + Twine(config->fileAlign));
}
// Handle /stack
if (auto *arg = args.getLastArg(OPT_stack))
parseNumbers(arg->getValue(), &config->stackReserve, &config->stackCommit);
// Handle /guard:cf
if (auto *arg = args.getLastArg(OPT_guard))
parseGuard(arg->getValue());
// Handle /heap
if (auto *arg = args.getLastArg(OPT_heap))
parseNumbers(arg->getValue(), &config->heapReserve, &config->heapCommit);
// Handle /version
if (auto *arg = args.getLastArg(OPT_version))
parseVersion(arg->getValue(), &config->majorImageVersion,
&config->minorImageVersion);
// Handle /subsystem
if (auto *arg = args.getLastArg(OPT_subsystem))
parseSubsystem(arg->getValue(), &config->subsystem,
&config->majorSubsystemVersion,
&config->minorSubsystemVersion);
// Handle /osversion
if (auto *arg = args.getLastArg(OPT_osversion)) {
parseVersion(arg->getValue(), &config->majorOSVersion,
&config->minorOSVersion);
} else {
config->majorOSVersion = config->majorSubsystemVersion;
config->minorOSVersion = config->minorSubsystemVersion;
}
// Handle /timestamp
if (llvm::opt::Arg *arg = args.getLastArg(OPT_timestamp, OPT_repro)) {
if (arg->getOption().getID() == OPT_repro) {
config->timestamp = 0;
config->repro = true;
} else {
config->repro = false;
StringRef value(arg->getValue());
if (value.getAsInteger(0, config->timestamp))
fatal(Twine("invalid timestamp: ") + value +
". Expected 32-bit integer");
}
} else {
config->repro = false;
config->timestamp = time(nullptr);
}
// Handle /alternatename
for (auto *arg : args.filtered(OPT_alternatename))
parseAlternateName(arg->getValue());
// Handle /include
for (auto *arg : args.filtered(OPT_incl))
addUndefined(arg->getValue());
// Handle /implib
if (auto *arg = args.getLastArg(OPT_implib))
config->implib = arg->getValue();
config->noimplib = args.hasArg(OPT_noimplib);
// Handle /opt.
bool doGC = debug == DebugKind::None || args.hasArg(OPT_profile);
Optional<ICFLevel> icfLevel = None;
if (args.hasArg(OPT_profile))
icfLevel = ICFLevel::None;
unsigned tailMerge = 1;
bool ltoDebugPM = false;
for (auto *arg : args.filtered(OPT_opt)) {
std::string str = StringRef(arg->getValue()).lower();
SmallVector<StringRef, 1> vec;
StringRef(str).split(vec, ',');
for (StringRef s : vec) {
if (s == "ref") {
doGC = true;
} else if (s == "noref") {
doGC = false;
} else if (s == "icf" || s.startswith("icf=")) {
icfLevel = ICFLevel::All;
} else if (s == "safeicf") {
icfLevel = ICFLevel::Safe;
} else if (s == "noicf") {
icfLevel = ICFLevel::None;
} else if (s == "lldtailmerge") {
tailMerge = 2;
} else if (s == "nolldtailmerge") {
tailMerge = 0;
} else if (s == "ltonewpassmanager") {
/* We always use the new PM. */
} else if (s == "ltodebugpassmanager") {
ltoDebugPM = true;
} else if (s == "noltodebugpassmanager") {
ltoDebugPM = false;
} else if (s.startswith("lldlto=")) {
StringRef optLevel = s.substr(7);
if (optLevel.getAsInteger(10, config->ltoo) || config->ltoo > 3)
error("/opt:lldlto: invalid optimization level: " + optLevel);
} else if (s.startswith("lldltojobs=")) {
StringRef jobs = s.substr(11);
if (!get_threadpool_strategy(jobs))
error("/opt:lldltojobs: invalid job count: " + jobs);
config->thinLTOJobs = jobs.str();
} else if (s.startswith("lldltopartitions=")) {
StringRef n = s.substr(17);
if (n.getAsInteger(10, config->ltoPartitions) ||
config->ltoPartitions == 0)
error("/opt:lldltopartitions: invalid partition count: " + n);
} else if (s != "lbr" && s != "nolbr")
error("/opt: unknown option: " + s);
}
}
if (!icfLevel)
icfLevel = doGC ? ICFLevel::All : ICFLevel::None;
config->doGC = doGC;
config->doICF = *icfLevel;
config->tailMerge =
(tailMerge == 1 && config->doICF != ICFLevel::None) || tailMerge == 2;
config->ltoDebugPassManager = ltoDebugPM;
// Handle /lldsavetemps
if (args.hasArg(OPT_lldsavetemps))
config->saveTemps = true;
// Handle /kill-at
if (args.hasArg(OPT_kill_at))
config->killAt = true;
// Handle /lldltocache
if (auto *arg = args.getLastArg(OPT_lldltocache))
config->ltoCache = arg->getValue();
// Handle /lldsavecachepolicy
if (auto *arg = args.getLastArg(OPT_lldltocachepolicy))
config->ltoCachePolicy = CHECK(
parseCachePruningPolicy(arg->getValue()),
Twine("/lldltocachepolicy: invalid cache policy: ") + arg->getValue());
// Handle /failifmismatch
for (auto *arg : args.filtered(OPT_failifmismatch))
checkFailIfMismatch(arg->getValue(), nullptr);
// Handle /merge
for (auto *arg : args.filtered(OPT_merge))
parseMerge(arg->getValue());
// Add default section merging rules after user rules. User rules take
// precedence, but we will emit a warning if there is a conflict.
parseMerge(".idata=.rdata");
parseMerge(".didat=.rdata");
parseMerge(".edata=.rdata");
parseMerge(".xdata=.rdata");
parseMerge(".bss=.data");
if (config->mingw) {
parseMerge(".ctors=.rdata");
parseMerge(".dtors=.rdata");
parseMerge(".CRT=.rdata");
}
// Handle /section
for (auto *arg : args.filtered(OPT_section))
parseSection(arg->getValue());
// Handle /align
if (auto *arg = args.getLastArg(OPT_align)) {
parseNumbers(arg->getValue(), &config->align);
if (!isPowerOf2_64(config->align))
error("/align: not a power of two: " + StringRef(arg->getValue()));
if (!args.hasArg(OPT_driver))
warn("/align specified without /driver; image may not run");
}
// Handle /aligncomm
for (auto *arg : args.filtered(OPT_aligncomm))
parseAligncomm(arg->getValue());
// Handle /manifestdependency.
for (auto *arg : args.filtered(OPT_manifestdependency))
config->manifestDependencies.insert(arg->getValue());
// Handle /manifest and /manifest:
if (auto *arg = args.getLastArg(OPT_manifest, OPT_manifest_colon)) {
if (arg->getOption().getID() == OPT_manifest)
config->manifest = Configuration::SideBySide;
else
parseManifest(arg->getValue());
}
// Handle /manifestuac
if (auto *arg = args.getLastArg(OPT_manifestuac))
parseManifestUAC(arg->getValue());
// Handle /manifestfile
if (auto *arg = args.getLastArg(OPT_manifestfile))
config->manifestFile = arg->getValue();
// Handle /manifestinput
for (auto *arg : args.filtered(OPT_manifestinput))
config->manifestInput.push_back(arg->getValue());
if (!config->manifestInput.empty() &&
config->manifest != Configuration::Embed) {
fatal("/manifestinput: requires /manifest:embed");
}
config->thinLTOEmitImportsFiles = args.hasArg(OPT_thinlto_emit_imports_files);
config->thinLTOIndexOnly = args.hasArg(OPT_thinlto_index_only) ||
args.hasArg(OPT_thinlto_index_only_arg);
config->thinLTOIndexOnlyArg =
args.getLastArgValue(OPT_thinlto_index_only_arg);
config->thinLTOPrefixReplace =
getOldNewOptions(args, OPT_thinlto_prefix_replace);
config->thinLTOObjectSuffixReplace =
getOldNewOptions(args, OPT_thinlto_object_suffix_replace);
config->ltoObjPath = args.getLastArgValue(OPT_lto_obj_path);
config->ltoCSProfileGenerate = args.hasArg(OPT_lto_cs_profile_generate);
config->ltoCSProfileFile = args.getLastArgValue(OPT_lto_cs_profile_file);
// Handle miscellaneous boolean flags.
config->ltoPGOWarnMismatch = args.hasFlag(OPT_lto_pgo_warn_mismatch,
OPT_lto_pgo_warn_mismatch_no, true);
config->allowBind = args.hasFlag(OPT_allowbind, OPT_allowbind_no, true);
config->allowIsolation =
args.hasFlag(OPT_allowisolation, OPT_allowisolation_no, true);
config->incremental =
args.hasFlag(OPT_incremental, OPT_incremental_no,
!config->doGC && config->doICF == ICFLevel::None &&
!args.hasArg(OPT_order) && !args.hasArg(OPT_profile));
config->integrityCheck =
args.hasFlag(OPT_integritycheck, OPT_integritycheck_no, false);
config->cetCompat = args.hasFlag(OPT_cetcompat, OPT_cetcompat_no, false);
config->nxCompat = args.hasFlag(OPT_nxcompat, OPT_nxcompat_no, true);
for (auto *arg : args.filtered(OPT_swaprun))
parseSwaprun(arg->getValue());
config->terminalServerAware =
!config->dll && args.hasFlag(OPT_tsaware, OPT_tsaware_no, true);
config->debugDwarf = debug == DebugKind::Dwarf;
config->debugGHashes = debug == DebugKind::GHash || debug == DebugKind::Full;
config->debugSymtab = debug == DebugKind::Symtab;
config->autoImport =
args.hasFlag(OPT_auto_import, OPT_auto_import_no, config->mingw);
config->pseudoRelocs = args.hasFlag(
OPT_runtime_pseudo_reloc, OPT_runtime_pseudo_reloc_no, config->mingw);
config->callGraphProfileSort = args.hasFlag(
OPT_call_graph_profile_sort, OPT_call_graph_profile_sort_no, true);
config->stdcallFixup =
args.hasFlag(OPT_stdcall_fixup, OPT_stdcall_fixup_no, config->mingw);
config->warnStdcallFixup = !args.hasArg(OPT_stdcall_fixup);
// Don't warn about long section names, such as .debug_info, for mingw or
// when -debug:dwarf is requested.
if (config->mingw || config->debugDwarf)
config->warnLongSectionNames = false;
config->lldmapFile = getMapFile(args, OPT_lldmap, OPT_lldmap_file);
config->mapFile = getMapFile(args, OPT_map, OPT_map_file);
if (config->lldmapFile != "" && config->lldmapFile == config->mapFile) {
warn("/lldmap and /map have the same output file '" + config->mapFile +
"'.\n>>> ignoring /lldmap");
config->lldmapFile.clear();
}
if (config->incremental && args.hasArg(OPT_profile)) {
warn("ignoring '/incremental' due to '/profile' specification");
config->incremental = false;
}
if (config->incremental && args.hasArg(OPT_order)) {
warn("ignoring '/incremental' due to '/order' specification");
config->incremental = false;
}
if (config->incremental && config->doGC) {
warn("ignoring '/incremental' because REF is enabled; use '/opt:noref' to "
"disable");
config->incremental = false;
}
if (config->incremental && config->doICF != ICFLevel::None) {
warn("ignoring '/incremental' because ICF is enabled; use '/opt:noicf' to "
"disable");
config->incremental = false;
}
if (errorCount())
return;
std::set<sys::fs::UniqueID> wholeArchives;
for (auto *arg : args.filtered(OPT_wholearchive_file))
if (Optional<StringRef> path = doFindFile(arg->getValue()))
if (Optional<sys::fs::UniqueID> id = getUniqueID(*path))
wholeArchives.insert(*id);
// A predicate returning true if a given path is an argument for
// /wholearchive:, or /wholearchive is enabled globally.
// This function is a bit tricky because "foo.obj /wholearchive:././foo.obj"
// needs to be handled as "/wholearchive:foo.obj foo.obj".
auto isWholeArchive = [&](StringRef path) -> bool {
if (args.hasArg(OPT_wholearchive_flag))
return true;
if (Optional<sys::fs::UniqueID> id = getUniqueID(path))
return wholeArchives.count(*id);
return false;
};
// Create a list of input files. These can be given as OPT_INPUT options
// and OPT_wholearchive_file options, and we also need to track OPT_start_lib
// and OPT_end_lib.
bool inLib = false;
for (auto *arg : args) {
switch (arg->getOption().getID()) {
case OPT_end_lib:
if (!inLib)
error("stray " + arg->getSpelling());
inLib = false;
break;
case OPT_start_lib:
if (inLib)
error("nested " + arg->getSpelling());
inLib = true;
break;
case OPT_wholearchive_file:
if (Optional<StringRef> path = findFile(arg->getValue()))
enqueuePath(*path, true, inLib);
break;
case OPT_INPUT:
if (Optional<StringRef> path = findFile(arg->getValue()))
enqueuePath(*path, isWholeArchive(*path), inLib);
break;
default:
// Ignore other options.
break;
}
}
// Read all input files given via the command line.
run();
if (errorCount())
return;
// We should have inferred a machine type by now from the input files, but if
// not we assume x64.
if (config->machine == IMAGE_FILE_MACHINE_UNKNOWN) {
warn("/machine is not specified. x64 is assumed");
config->machine = AMD64;
addWinSysRootLibSearchPaths();
}
config->wordsize = config->is64() ? 8 : 4;
// Process files specified as /defaultlib. These must be processed after
// addWinSysRootLibSearchPaths(), which is why they are in a separate loop.
for (auto *arg : args.filtered(OPT_defaultlib))
if (Optional<StringRef> path = findLib(arg->getValue()))
enqueuePath(*path, false, false);
run();
if (errorCount())
return;
// Handle /safeseh, x86 only, on by default, except for mingw.
if (config->machine == I386) {
config->safeSEH = args.hasFlag(OPT_safeseh, OPT_safeseh_no, !config->mingw);
config->noSEH = args.hasArg(OPT_noseh);
}
// Handle /functionpadmin
for (auto *arg : args.filtered(OPT_functionpadmin, OPT_functionpadmin_opt))
parseFunctionPadMin(arg, config->machine);
if (tar) {
tar->append("response.txt",
createResponseFile(args, filePaths,
ArrayRef<StringRef>(searchPaths).slice(1)));
}
// Handle /largeaddressaware
config->largeAddressAware = args.hasFlag(
OPT_largeaddressaware, OPT_largeaddressaware_no, config->is64());
// Handle /highentropyva
config->highEntropyVA =
config->is64() &&
args.hasFlag(OPT_highentropyva, OPT_highentropyva_no, true);
if (!config->dynamicBase &&
(config->machine == ARMNT || config->machine == ARM64))
error("/dynamicbase:no is not compatible with " +
machineToStr(config->machine));
// Handle /export
for (auto *arg : args.filtered(OPT_export)) {
Export e = parseExport(arg->getValue());
if (config->machine == I386) {
if (!isDecorated(e.name))
e.name = saver().save("_" + e.name);
if (!e.extName.empty() && !isDecorated(e.extName))
e.extName = saver().save("_" + e.extName);
}
config->exports.push_back(e);
}
// Handle /def
if (auto *arg = args.getLastArg(OPT_deffile)) {
// parseModuleDefs mutates Config object.
parseModuleDefs(arg->getValue());
}
// Handle generation of import library from a def file.
if (!args.hasArg(OPT_INPUT, OPT_wholearchive_file)) {
fixupExports();
if (!config->noimplib)
createImportLibrary(/*asLib=*/true);
return;
}
// Windows specific -- if no /subsystem is given, we need to infer
// that from entry point name. Must happen before /entry handling,
// and after the early return when just writing an import library.
if (config->subsystem == IMAGE_SUBSYSTEM_UNKNOWN) {
config->subsystem = inferSubsystem();
if (config->subsystem == IMAGE_SUBSYSTEM_UNKNOWN)
fatal("subsystem must be defined");
}
// Handle /entry and /dll
if (auto *arg = args.getLastArg(OPT_entry)) {
config->entry = addUndefined(mangle(arg->getValue()));
} else if (!config->entry && !config->noEntry) {
if (args.hasArg(OPT_dll)) {
StringRef s = (config->machine == I386) ? "__DllMainCRTStartup@12"
: "_DllMainCRTStartup";
config->entry = addUndefined(s);
} else if (config->driverWdm) {
// /driver:wdm implies /entry:_NtProcessStartup
config->entry = addUndefined(mangle("_NtProcessStartup"));
} else {
// Windows specific -- If entry point name is not given, we need to
// infer that from user-defined entry name.
StringRef s = findDefaultEntry();
if (s.empty())
fatal("entry point must be defined");
config->entry = addUndefined(s);
log("Entry name inferred: " + s);
}
}
// Handle /delayload
for (auto *arg : args.filtered(OPT_delayload)) {
config->delayLoads.insert(StringRef(arg->getValue()).lower());
if (config->machine == I386) {
config->delayLoadHelper = addUndefined("___delayLoadHelper2@8");
} else {
config->delayLoadHelper = addUndefined("__delayLoadHelper2");
}
}
// Set default image name if neither /out or /def set it.
if (config->outputFile.empty()) {
config->outputFile = getOutputPath(
(*args.filtered(OPT_INPUT, OPT_wholearchive_file).begin())->getValue());
}
// Fail early if an output file is not writable.
if (auto e = tryCreateFile(config->outputFile)) {
error("cannot open output file " + config->outputFile + ": " + e.message());
return;
}
if (shouldCreatePDB) {
// Put the PDB next to the image if no /pdb flag was passed.
if (config->pdbPath.empty()) {
config->pdbPath = config->outputFile;
sys::path::replace_extension(config->pdbPath, ".pdb");
}
// The embedded PDB path should be the absolute path to the PDB if no
// /pdbaltpath flag was passed.
if (config->pdbAltPath.empty()) {
config->pdbAltPath = config->pdbPath;
// It's important to make the path absolute and remove dots. This path
// will eventually be written into the PE header, and certain Microsoft
// tools won't work correctly if these assumptions are not held.
sys::fs::make_absolute(config->pdbAltPath);
sys::path::remove_dots(config->pdbAltPath);
} else {
// Don't do this earlier, so that Config->OutputFile is ready.
parsePDBAltPath(config->pdbAltPath);
}
}
// Set default image base if /base is not given.
if (config->imageBase == uint64_t(-1))
config->imageBase = getDefaultImageBase();
ctx.symtab.addSynthetic(mangle("__ImageBase"), nullptr);
if (config->machine == I386) {
ctx.symtab.addAbsolute("___safe_se_handler_table", 0);
ctx.symtab.addAbsolute("___safe_se_handler_count", 0);
}
ctx.symtab.addAbsolute(mangle("__guard_fids_count"), 0);
ctx.symtab.addAbsolute(mangle("__guard_fids_table"), 0);
ctx.symtab.addAbsolute(mangle("__guard_flags"), 0);
ctx.symtab.addAbsolute(mangle("__guard_iat_count"), 0);
ctx.symtab.addAbsolute(mangle("__guard_iat_table"), 0);
ctx.symtab.addAbsolute(mangle("__guard_longjmp_count"), 0);
ctx.symtab.addAbsolute(mangle("__guard_longjmp_table"), 0);
// Needed for MSVC 2017 15.5 CRT.
ctx.symtab.addAbsolute(mangle("__enclave_config"), 0);
// Needed for MSVC 2019 16.8 CRT.
ctx.symtab.addAbsolute(mangle("__guard_eh_cont_count"), 0);
ctx.symtab.addAbsolute(mangle("__guard_eh_cont_table"), 0);
if (config->pseudoRelocs) {
ctx.symtab.addAbsolute(mangle("__RUNTIME_PSEUDO_RELOC_LIST__"), 0);
ctx.symtab.addAbsolute(mangle("__RUNTIME_PSEUDO_RELOC_LIST_END__"), 0);
}
if (config->mingw) {
ctx.symtab.addAbsolute(mangle("__CTOR_LIST__"), 0);
ctx.symtab.addAbsolute(mangle("__DTOR_LIST__"), 0);
}
// This code may add new undefined symbols to the link, which may enqueue more
// symbol resolution tasks, so we need to continue executing tasks until we
// converge.
do {
// Windows specific -- if entry point is not found,
// search for its mangled names.
if (config->entry)
mangleMaybe(config->entry);
// Windows specific -- Make sure we resolve all dllexported symbols.
for (Export &e : config->exports) {
if (!e.forwardTo.empty())
continue;
e.sym = addUndefined(e.name);
if (!e.directives)
e.symbolName = mangleMaybe(e.sym);
}
// Add weak aliases. Weak aliases is a mechanism to give remaining
// undefined symbols final chance to be resolved successfully.
for (auto pair : config->alternateNames) {
StringRef from = pair.first;
StringRef to = pair.second;
Symbol *sym = ctx.symtab.find(from);
if (!sym)
continue;
if (auto *u = dyn_cast<Undefined>(sym))
if (!u->weakAlias)
u->weakAlias = ctx.symtab.addUndefined(to);
}
// If any inputs are bitcode files, the LTO code generator may create
// references to library functions that are not explicit in the bitcode
// file's symbol table. If any of those library functions are defined in a
// bitcode file in an archive member, we need to arrange to use LTO to
// compile those archive members by adding them to the link beforehand.
if (!ctx.bitcodeFileInstances.empty())
for (auto *s : lto::LTO::getRuntimeLibcallSymbols())
ctx.symtab.addLibcall(s);
// Windows specific -- if __load_config_used can be resolved, resolve it.
if (ctx.symtab.findUnderscore("_load_config_used"))
addUndefined(mangle("_load_config_used"));
if (args.hasArg(OPT_include_optional)) {
// Handle /includeoptional
for (auto *arg : args.filtered(OPT_include_optional))
if (isa_and_nonnull<LazyArchive>(ctx.symtab.find(arg->getValue())))
addUndefined(arg->getValue());
}
} while (run());
// Create wrapped symbols for -wrap option.
std::vector<WrappedSymbol> wrapped = addWrappedSymbols(ctx, args);
// Load more object files that might be needed for wrapped symbols.
if (!wrapped.empty())
while (run());
if (config->autoImport || config->stdcallFixup) {
// MinGW specific.
// Load any further object files that might be needed for doing automatic
// imports, and do stdcall fixups.
//
// For cases with no automatically imported symbols, this iterates once
// over the symbol table and doesn't do anything.
//
// For the normal case with a few automatically imported symbols, this
// should only need to be run once, since each new object file imported
// is an import library and wouldn't add any new undefined references,
// but there's nothing stopping the __imp_ symbols from coming from a
// normal object file as well (although that won't be used for the
// actual autoimport later on). If this pass adds new undefined references,
// we won't iterate further to resolve them.
//
// If stdcall fixups only are needed for loading import entries from
// a DLL without import library, this also just needs running once.
// If it ends up pulling in more object files from static libraries,
// (and maybe doing more stdcall fixups along the way), this would need
// to loop these two calls.
ctx.symtab.loadMinGWSymbols();
run();
}
// At this point, we should not have any symbols that cannot be resolved.
// If we are going to do codegen for link-time optimization, check for
// unresolvable symbols first, so we don't spend time generating code that
// will fail to link anyway.
if (!ctx.bitcodeFileInstances.empty() && !config->forceUnresolved)
ctx.symtab.reportUnresolvable();
if (errorCount())
return;
config->hadExplicitExports = !config->exports.empty();
if (config->mingw) {
// In MinGW, all symbols are automatically exported if no symbols
// are chosen to be exported.
maybeExportMinGWSymbols(args);
}
// Do LTO by compiling bitcode input files to a set of native COFF files then
// link those files (unless -thinlto-index-only was given, in which case we
// resolve symbols and write indices, but don't generate native code or link).
ctx.symtab.compileBitcodeFiles();
// If -thinlto-index-only is given, we should create only "index
// files" and not object files. Index file creation is already done
// in compileBitcodeFiles, so we are done if that's the case.
if (config->thinLTOIndexOnly)
return;
// If we generated native object files from bitcode files, this resolves
// references to the symbols we use from them.
run();
// Apply symbol renames for -wrap.
if (!wrapped.empty())
wrapSymbols(ctx, wrapped);
// Resolve remaining undefined symbols and warn about imported locals.
ctx.symtab.resolveRemainingUndefines();
if (errorCount())
return;
if (config->mingw) {
// Make sure the crtend.o object is the last object file. This object
// file can contain terminating section chunks that need to be placed
// last. GNU ld processes files and static libraries explicitly in the
// order provided on the command line, while lld will pull in needed
// files from static libraries only after the last object file on the
// command line.
for (auto i = ctx.objFileInstances.begin(), e = ctx.objFileInstances.end();
i != e; i++) {
ObjFile *file = *i;
if (isCrtend(file->getName())) {
ctx.objFileInstances.erase(i);
ctx.objFileInstances.push_back(file);
break;
}
}
}
// Windows specific -- when we are creating a .dll file, we also
// need to create a .lib file. In MinGW mode, we only do that when the
// -implib option is given explicitly, for compatibility with GNU ld.
if (!config->exports.empty() || config->dll) {
fixupExports();
if (!config->noimplib && (!config->mingw || !config->implib.empty()))
createImportLibrary(/*asLib=*/false);
assignExportOrdinals();
}
// Handle /output-def (MinGW specific).
if (auto *arg = args.getLastArg(OPT_output_def))
writeDefFile(arg->getValue());
// Set extra alignment for .comm symbols
for (auto pair : config->alignComm) {
StringRef name = pair.first;
uint32_t alignment = pair.second;
Symbol *sym = ctx.symtab.find(name);
if (!sym) {
warn("/aligncomm symbol " + name + " not found");
continue;
}
// If the symbol isn't common, it must have been replaced with a regular
// symbol, which will carry its own alignment.
auto *dc = dyn_cast<DefinedCommon>(sym);
if (!dc)
continue;
CommonChunk *c = dc->getChunk();
c->setAlignment(std::max(c->getAlignment(), alignment));
}
// Windows specific -- Create an embedded or side-by-side manifest.
// /manifestdependency: enables /manifest unless an explicit /manifest:no is
// also passed.
if (config->manifest == Configuration::Embed)
addBuffer(createManifestRes(), false, false);
else if (config->manifest == Configuration::SideBySide ||
(config->manifest == Configuration::Default &&
!config->manifestDependencies.empty()))
createSideBySideManifest();
// Handle /order. We want to do this at this moment because we
// need a complete list of comdat sections to warn on nonexistent
// functions.
if (auto *arg = args.getLastArg(OPT_order)) {
if (args.hasArg(OPT_call_graph_ordering_file))
error("/order and /call-graph-order-file may not be used together");
parseOrderFile(ctx, arg->getValue());
config->callGraphProfileSort = false;
}
// Handle /call-graph-ordering-file and /call-graph-profile-sort (default on).
if (config->callGraphProfileSort) {
if (auto *arg = args.getLastArg(OPT_call_graph_ordering_file)) {
parseCallGraphFile(ctx, arg->getValue());
}
readCallGraphsFromObjectFiles(ctx);
}
// Handle /print-symbol-order.
if (auto *arg = args.getLastArg(OPT_print_symbol_order))
config->printSymbolOrder = arg->getValue();
// Identify unreferenced COMDAT sections.
if (config->doGC) {
if (config->mingw) {
// markLive doesn't traverse .eh_frame, but the personality function is
// only reached that way. The proper solution would be to parse and
// traverse the .eh_frame section, like the ELF linker does.
// For now, just manually try to retain the known possible personality
// functions. This doesn't bring in more object files, but only marks
// functions that already have been included to be retained.
for (const char *n : {"__gxx_personality_v0", "__gcc_personality_v0"}) {
Defined *d = dyn_cast_or_null<Defined>(ctx.symtab.findUnderscore(n));
if (d && !d->isGCRoot) {
d->isGCRoot = true;
config->gcroot.push_back(d);
}
}
}
markLive(ctx);
}
// Needs to happen after the last call to addFile().
convertResources();
// Identify identical COMDAT sections to merge them.
if (config->doICF != ICFLevel::None) {
findKeepUniqueSections(ctx);
doICF(ctx, config->doICF);
}
// Write the result.
writeResult(ctx);
// Stop early so we can print the results.
rootTimer.stop();
if (config->showTiming)
ctx.rootTimer.print();
}
} // namespace coff
} // namespace lld
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