/
Driver.cpp
2497 lines (2207 loc) · 86.5 KB
/
Driver.cpp
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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/CommonLinkerContext.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/StringSwitch.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/TargetParser/Triple.h"
#include "llvm/ToolDrivers/llvm-lib/LibDriver.h"
#include <algorithm>
#include <future>
#include <memory>
#include <optional>
#include <tuple>
using namespace llvm;
using namespace llvm::object;
using namespace llvm::COFF;
using namespace llvm::sys;
namespace lld::coff {
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)";
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;
}
// Parse options of the form "old;new[;extra]".
static std::tuple<StringRef, StringRef, StringRef>
getOldNewOptionsExtra(opt::InputArgList &args, unsigned id) {
auto [oldDir, second] = getOldNewOptions(args, id);
auto [newDir, extraDir] = second.split(';');
return {oldDir, newDir, extraDir};
}
// Drop directory components and replace extension with
// ".exe", ".dll" or ".sys".
static std::string getOutputPath(StringRef path, bool isDll, bool isDriver) {
StringRef ext = ".exe";
if (isDll)
ext = ".dll";
else if (isDriver)
ext = ".sys";
return (sys::path::stem(path) + ext).str();
}
// Returns true if S matches /crtend.?\.o$/.
static bool isCrtend(StringRef s) {
if (!s.ends_with(".o"))
return false;
s = s.drop_back(2);
if (s.ends_with("crtend"))
return true;
return !s.empty() && s.drop_back().ends_with("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.
StringRef LinkerDriver::mangle(StringRef sym) {
assert(ctx.config.machine != IMAGE_FILE_MACHINE_UNKNOWN);
if (ctx.config.machine == I386)
return saver().save("_" + sym);
return sym;
}
llvm::Triple::ArchType LinkerDriver::getArch() {
switch (ctx.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 (ctx.driver.tar)
ctx.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 (ctx.config.mingw) {
ctx.symtab.addFile(make<DLLFile>(ctx, mbref));
break;
}
if (filename.ends_with_insensitive(".dll")) {
error(filename + ": bad file type. Did you specify a DLL instead of an "
"import library?");
break;
}
[[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 [mb, ec] = future->get();
if (ec) {
// Retry reading the file (synchronously) now that we may have added
// winsysroot search paths from SymbolTable::addFile().
// Retrying synchronously is important for keeping the order of inputs
// consistent.
// This makes it so that if the user passes something in the winsysroot
// before something we can find with an architecture, we won't find the
// winsysroot file.
if (std::optional<StringRef> retryPath = findFileIfNew(pathStr)) {
auto retryMb = MemoryBuffer::getFile(*retryPath, /*IsText=*/false,
/*RequiresNullTerminator=*/false);
ec = retryMb.getError();
if (!ec)
mb = std::move(*retryMb);
} else {
// We've already handled this file.
return;
}
}
if (ec) {
std::string msg = "could not open '" + pathStr + "': " + ec.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 (ctx.optTable.findNearest(pathStr, nearest) > 1)
error(msg);
else
error(msg + "; did you mean '" + nearest + "'");
} else
ctx.driver.addBuffer(std::move(mb), 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 if (magic == file_magic::coff_cl_gl_object) {
error(mb.getBufferIdentifier() +
": is not a native COFF file. Recompile without /GL?");
return;
} 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(ctx, 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([=]() {
ctx.driver.addArchiveBuffer(mb, toCOFFString(ctx, sym), parentName,
offsetInArchive);
});
return;
}
std::string childName =
CHECK(c.getFullName(),
"could not get the filename for the member defining symbol " +
toCOFFString(ctx, 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.
ctx.driver.addArchiveBuffer(takeBuffer(std::move(mbOrErr.first)),
toCOFFString(ctx, sym), "",
/*OffsetInArchive=*/0);
});
}
bool LinkerDriver::isDecorated(StringRef sym) {
return sym.starts_with("@") || sym.contains("@@") || sym.starts_with("?") ||
(!ctx.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(ctx);
// .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 (ctx.config.machine == I386 && ctx.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.source = ExportSource::Directives;
ctx.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 (std::optional<StringRef> path = findLibIfNew(arg->getValue()))
enqueuePath(*path, false, false);
break;
case OPT_entry:
ctx.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:
ctx.config.manifestDependencies.insert(arg->getValue());
break;
case OPT_merge:
parseMerge(arg->getValue());
break;
case OPT_nodefaultlib:
ctx.config.noDefaultLibs.insert(findLib(arg->getValue()).lower());
break;
case OPT_release:
ctx.config.writeCheckSum = true;
break;
case OPT_section:
parseSection(arg->getValue());
break;
case OPT_stack:
parseNumbers(arg->getValue(), &ctx.config.stackReserve,
&ctx.config.stackCommit);
break;
case OPT_subsystem: {
bool gotVersion = false;
parseSubsystem(arg->getValue(), &ctx.config.subsystem,
&ctx.config.majorSubsystemVersion,
&ctx.config.minorSubsystemVersion, &gotVersion);
if (gotVersion) {
ctx.config.majorOSVersion = ctx.config.majorSubsystemVersion;
ctx.config.minorOSVersion = ctx.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:
case OPT_inferasanlibs:
case OPT_inferasanlibs_no:
break;
default:
error(arg->getSpelling() + " is not allowed in .drectve (" +
toString(file) + ")");
}
}
}
// 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::findFile(StringRef filename) {
auto getFilename = [this](StringRef filename) -> StringRef {
if (ctx.config.vfs)
if (auto statOrErr = ctx.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 std::optional<sys::fs::UniqueID> getUniqueID(StringRef path) {
sys::fs::UniqueID ret;
if (sys::fs::getUniqueID(path, ret))
return std::nullopt;
return ret;
}
// Resolves a file path. This never returns the same path
// (in that case, it returns std::nullopt).
std::optional<StringRef> LinkerDriver::findFileIfNew(StringRef filename) {
StringRef path = findFile(filename);
if (std::optional<sys::fs::UniqueID> id = getUniqueID(path)) {
bool seen = !visitedFiles.insert(*id).second;
if (seen)
return std::nullopt;
}
if (path.ends_with_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::findLibMinGW(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 findFile(libName);
}
// Find library file from search path.
StringRef LinkerDriver::findLib(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 = findFile(filename);
// For MinGW, if the find above didn't turn up anything, try
// looking for a MinGW formatted library name.
if (ctx.config.mingw && ret == filename)
return findLibMinGW(filename);
return ret;
}
// Resolves a library path. /nodefaultlib options are taken into
// consideration. This never returns the same path (in that case,
// it returns std::nullopt).
std::optional<StringRef> LinkerDriver::findLibIfNew(StringRef filename) {
if (ctx.config.noDefaultLibAll)
return std::nullopt;
if (!visitedLibs.insert(filename.lower()).second)
return std::nullopt;
StringRef path = findLib(filename);
if (ctx.config.noDefaultLibs.count(path.lower()))
return std::nullopt;
if (std::optional<sys::fs::UniqueID> id = getUniqueID(path))
if (!visitedFiles.insert(*id).second)
return std::nullopt;
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.
std::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)) {
std::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() {
std::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;
ctx.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(ctx.config.subsystem != IMAGE_SUBSYSTEM_UNKNOWN &&
"must handle /subsystem before calling this");
if (ctx.config.mingw)
return mangle(ctx.config.subsystem == IMAGE_SUBSYSTEM_WINDOWS_GUI
? "WinMainCRTStartup"
: "mainCRTStartup");
if (ctx.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 (ctx.config.dll)
return IMAGE_SUBSYSTEM_WINDOWS_GUI;
if (ctx.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;
}
uint64_t LinkerDriver::getDefaultImageBase() {
if (ctx.config.is64())
return ctx.config.dll ? 0x180000000 : 0x140000000;
return ctx.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;
}
std::string LinkerDriver::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 = ctx.config.outputFile;
return (outFile.substr(0, outFile.rfind('.')) + ".map").str();
}
std::string LinkerDriver::getImplibPath() {
if (!ctx.config.implib.empty())
return std::string(ctx.config.implib);
SmallString<128> out = StringRef(ctx.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
//
std::string LinkerDriver::getImportName(bool asLib) {
SmallString<128> out;
if (ctx.config.importName.empty()) {
out.assign(sys::path::filename(ctx.config.outputFile));
if (asLib)
sys::path::replace_extension(out, ".dll");
} else {
out.assign(ctx.config.importName);
if (!sys::path::has_extension(out))
sys::path::replace_extension(out,
(ctx.config.dll || asLib) ? ".dll" : ".exe");
}
return std::string(out.str());
}
void LinkerDriver::createImportLibrary(bool asLib) {
std::vector<COFFShortExport> exports;
for (Export &e1 : ctx.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 (!ctx.config.incremental) {
checkError(writeImportLibrary(libName, path, exports, ctx.config.machine,
ctx.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, ctx.config.machine,
ctx.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,
ctx.config.machine, ctx.config.mingw)) {
checkError(std::move(e));
return;
}