ldc/driver/linker-gcc.cpp

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//===-- linker-gcc.cpp ----------------------------------------------------===//
//
// LDC the LLVM D compiler
//
// This file is distributed under the BSD-style LDC license. See the LICENSE
// file for details.
//
//===----------------------------------------------------------------------===//
#include "errors.h"
#include "driver/cl_options.h"
#include "driver/exe_path.h"
#include "driver/tool.h"
#include "gen/irstate.h"
#include "gen/logger.h"
#include "gen/optimizer.h"
#include "llvm/ProfileData/InstrProf.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
//////////////////////////////////////////////////////////////////////////////
static llvm::cl::opt<std::string>
ltoLibrary("flto-binary", llvm::cl::ZeroOrMore,
llvm::cl::desc("Set the linker LTO plugin library file (e.g. "
"LLVMgold.so (Unixes) or libLTO.dylib (Darwin))"),
llvm::cl::value_desc("file"));
//////////////////////////////////////////////////////////////////////////////
// LTO functionality
#if LDC_LLVM_VER >= 309
namespace {
void addLinkerFlag(std::vector<std::string> &args, const llvm::Twine &flag) {
args.push_back("-Xlinker");
args.push_back(flag.str());
}
std::string getLTOGoldPluginPath() {
if (!ltoLibrary.empty()) {
if (llvm::sys::fs::exists(ltoLibrary))
return ltoLibrary;
error(Loc(), "-flto-binary: file '%s' not found", ltoLibrary.c_str());
fatal();
} else {
std::string searchPaths[] = {
// The plugin packaged with LDC has a "-ldc" suffix.
exe_path::prependLibDir("LLVMgold-ldc.so"),
// Perhaps the user copied the plugin to LDC's lib dir.
exe_path::prependLibDir("LLVMgold.so"),
#if __LP64__
"/usr/local/lib64/LLVMgold.so",
#endif
"/usr/local/lib/LLVMgold.so",
#if __LP64__
"/usr/lib64/LLVMgold.so",
#endif
"/usr/lib/LLVMgold.so",
"/usr/lib/bfd-plugins/LLVMgold.so",
};
// Try all searchPaths and early return upon the first path found.
for (const auto &p : searchPaths) {
if (llvm::sys::fs::exists(p))
return p;
}
error(Loc(), "The LLVMgold.so plugin (needed for LTO) was not found. You "
"can specify its path with -flto-binary=<file>.");
fatal();
}
}
void addLTOGoldPluginFlags(std::vector<std::string> &args) {
addLinkerFlag(args, "-plugin");
addLinkerFlag(args, getLTOGoldPluginPath());
if (opts::isUsingThinLTO())
addLinkerFlag(args, "-plugin-opt=thinlto");
if (!opts::mCPU.empty())
addLinkerFlag(args, llvm::Twine("-plugin-opt=mcpu=") + opts::mCPU);
// Use the O-level passed to LDC as the O-level for LTO, but restrict it to
// the [0, 3] range that can be passed to the linker plugin.
static char optChars[15] = "-plugin-opt=O0";
optChars[13] = '0' + std::min<char>(optLevel(), 3);
addLinkerFlag(args, optChars);
#if LDC_LLVM_VER >= 400
const llvm::TargetOptions &TO = gTargetMachine->Options;
if (TO.FunctionSections)
addLinkerFlag(args, "-plugin-opt=-function-sections");
if (TO.DataSections)
addLinkerFlag(args, "-plugin-opt=-data-sections");
#endif
}
// Returns an empty string when libLTO.dylib was not specified nor found.
std::string getLTOdylibPath() {
if (!ltoLibrary.empty()) {
if (llvm::sys::fs::exists(ltoLibrary))
return ltoLibrary;
error(Loc(), "-flto-binary: '%s' not found", ltoLibrary.c_str());
fatal();
} else {
// The plugin packaged with LDC has a "-ldc" suffix.
std::string searchPath = exe_path::prependLibDir("libLTO-ldc.dylib");
if (llvm::sys::fs::exists(searchPath))
return searchPath;
return "";
}
}
void addDarwinLTOFlags(std::vector<std::string> &args) {
std::string dylibPath = getLTOdylibPath();
if (!dylibPath.empty()) {
args.push_back("-lto_library");
args.push_back(std::move(dylibPath));
}
}
/// Adds the required linker flags for LTO builds to args.
void addLTOLinkFlags(std::vector<std::string> &args) {
if (global.params.targetTriple->isOSLinux() ||
global.params.targetTriple->isOSFreeBSD() ||
global.params.targetTriple->isOSNetBSD() ||
global.params.targetTriple->isOSOpenBSD() ||
global.params.targetTriple->isOSDragonFly()) {
// Assume that ld.gold or ld.bfd is used with plugin support.
addLTOGoldPluginFlags(args);
} else if (global.params.targetTriple->isOSDarwin()) {
addDarwinLTOFlags(args);
}
}
} // anonymous namespace
#endif // LDC_LLVM_VER >= 309
//////////////////////////////////////////////////////////////////////////////
namespace {
class ArgsBuilder {
public:
std::vector<std::string> args;
void build(llvm::StringRef outputPath,
llvm::cl::boolOrDefault fullyStaticFlag);
private:
void addSanitizers();
void addUserSwitches();
void addDefaultLibs();
void addArch();
};
//////////////////////////////////////////////////////////////////////////////
void ArgsBuilder::build(llvm::StringRef outputPath,
llvm::cl::boolOrDefault fullyStaticFlag) {
// object files
for (unsigned i = 0; i < global.params.objfiles->dim; i++)
args.push_back((*global.params.objfiles)[i]);
// Link with profile-rt library when generating an instrumented binary.
// profile-rt uses Phobos (MD5 hashing) and therefore must be passed on the
// commandline before Phobos.
if (global.params.genInstrProf) {
#if LDC_LLVM_VER >= 308
if (global.params.targetTriple->isOSLinux()) {
// For Linux, explicitly define __llvm_profile_runtime as undefined
// symbol, so that the initialization part of profile-rt is linked in.
args.push_back(
("-Wl,-u," + llvm::getInstrProfRuntimeHookVarName()).str());
}
#endif
args.push_back("-lldc-profile-rt");
}
// user libs
for (unsigned i = 0; i < global.params.libfiles->dim; i++)
args.push_back((*global.params.libfiles)[i]);
if (global.params.dll) {
args.push_back("-shared");
}
if (fullyStaticFlag == llvm::cl::BOU_TRUE) {
args.push_back("-static");
}
args.push_back("-o");
args.push_back(outputPath);
addSanitizers();
#if LDC_LLVM_VER >= 309
// Add LTO link flags before adding the user link switches, such that the user
// can pass additional options to the LTO plugin.
if (opts::isUsingLTO())
addLTOLinkFlags(args);
#endif
addUserSwitches();
// libs added via pragma(lib, libname)
for (unsigned i = 0; i < global.params.linkswitches->dim; i++) {
args.push_back((*global.params.linkswitches)[i]);
}
if (global.params.targetTriple->getOS() == llvm::Triple::Linux) {
// Make sure we don't do --gc-sections when generating a profile-
// instrumented binary. The runtime relies on magic sections, which
// would be stripped by gc-section on older version of ld, see bug:
// https://sourceware.org/bugzilla/show_bug.cgi?id=19161
if (!opts::disableLinkerStripDead && !global.params.genInstrProf) {
args.push_back("-Wl,--gc-sections");
}
}
addDefaultLibs();
addArch();
}
//////////////////////////////////////////////////////////////////////////////
// Requires clang.
void ArgsBuilder::addSanitizers() {
if (opts::sanitize == opts::AddressSanitizer) {
args.push_back("-fsanitize=address");
}
if (opts::sanitize == opts::MemorySanitizer) {
args.push_back("-fsanitize=memory");
}
if (opts::sanitize == opts::ThreadSanitizer) {
args.push_back("-fsanitize=thread");
}
}
//////////////////////////////////////////////////////////////////////////////
void ArgsBuilder::addUserSwitches() {
// additional linker and cc switches (preserve order across both lists)
for (unsigned ilink = 0, icc = 0;;) {
unsigned linkpos = ilink < opts::linkerSwitches.size()
? opts::linkerSwitches.getPosition(ilink)
: std::numeric_limits<unsigned>::max();
unsigned ccpos = icc < opts::ccSwitches.size()
? opts::ccSwitches.getPosition(icc)
: std::numeric_limits<unsigned>::max();
if (linkpos < ccpos) {
const std::string &p = opts::linkerSwitches[ilink++];
// Don't push -l and -L switches using -Xlinker, but pass them indirectly
// via GCC. This makes sure user-defined paths take precedence over
// GCC's builtin LIBRARY_PATHs.
// Options starting with `-Wl,`, -shared or -static are not handled by
// the linker and must be passed to the driver.
auto str = llvm::StringRef(p);
if (!(str.startswith("-l") || str.startswith("-L") ||
str.startswith("-Wl,") || str.startswith("-shared") ||
str.startswith("-static"))) {
args.push_back("-Xlinker");
}
args.push_back(p);
} else if (ccpos < linkpos) {
args.push_back(opts::ccSwitches[icc++]);
} else {
break;
}
}
}
//////////////////////////////////////////////////////////////////////////////
void ArgsBuilder::addDefaultLibs() {
bool addSoname = false;
switch (global.params.targetTriple->getOS()) {
case llvm::Triple::Linux:
addSoname = true;
if (global.params.targetTriple->getEnvironment() == llvm::Triple::Android) {
args.push_back("-ldl");
args.push_back("-lm");
break;
}
args.push_back("-lrt");
// fallthrough
case llvm::Triple::Darwin:
case llvm::Triple::MacOSX:
args.push_back("-ldl");
// fallthrough
case llvm::Triple::FreeBSD:
case llvm::Triple::NetBSD:
case llvm::Triple::OpenBSD:
case llvm::Triple::DragonFly:
addSoname = true;
args.push_back("-lpthread");
args.push_back("-lm");
break;
case llvm::Triple::Solaris:
args.push_back("-lm");
args.push_back("-lumem");
args.push_back("-lsocket");
args.push_back("-lnsl");
break;
default:
// OS not yet handled, will probably lead to linker errors.
// FIXME: Win32.
break;
}
if (global.params.targetTriple->isWindowsGNUEnvironment()) {
// This is really more of a kludge, as linking in the Winsock functions
// should be handled by the pragma(lib, ...) in std.socket, but it
// makes LDC behave as expected for now.
args.push_back("-lws2_32");
}
if (global.params.dll && addSoname && !opts::soname.empty()) {
args.push_back("-Wl,-soname," + opts::soname);
}
}
//////////////////////////////////////////////////////////////////////////////
void ArgsBuilder::addArch() {
// Only specify -m32/-m64 for architectures where the two variants actually
// exist (as e.g. the GCC ARM toolchain doesn't recognize the switches).
// MIPS does not have -m32/-m64 but requires -mabi=.
if (global.params.targetTriple->get64BitArchVariant().getArch() !=
llvm::Triple::UnknownArch &&
global.params.targetTriple->get32BitArchVariant().getArch() !=
llvm::Triple::UnknownArch) {
if (global.params.targetTriple->get64BitArchVariant().getArch() ==
llvm::Triple::mips64 ||
global.params.targetTriple->get64BitArchVariant().getArch() ==
llvm::Triple::mips64el) {
switch (getMipsABI()) {
case MipsABI::EABI:
args.push_back("-mabi=eabi");
break;
case MipsABI::O32:
args.push_back("-mabi=32");
break;
case MipsABI::N32:
args.push_back("-mabi=n32");
break;
case MipsABI::N64:
args.push_back("-mabi=64");
break;
case MipsABI::Unknown:
break;
}
} else {
switch (global.params.targetTriple->getArch()) {
case llvm::Triple::arm:
case llvm::Triple::armeb:
case llvm::Triple::aarch64:
case llvm::Triple::aarch64_be:
#if LDC_LLVM_VER == 305
case llvm::Triple::arm64:
case llvm::Triple::arm64_be:
#endif
break;
default:
if (global.params.is64bit) {
args.push_back("-m64");
} else {
args.push_back("-m32");
}
}
}
}
}
} // anonymous namespace
//////////////////////////////////////////////////////////////////////////////
int linkObjToBinaryGcc(llvm::StringRef outputPath,
llvm::cl::boolOrDefault fullyStaticFlag) {
// find gcc for linking
const std::string tool = getGcc();
// build arguments
ArgsBuilder argsBuilder;
argsBuilder.build(outputPath, fullyStaticFlag);
Logger::println("Linking with: ");
Stream logstr = Logger::cout();
for (const auto &arg : argsBuilder.args) {
if (!arg.empty()) {
logstr << "'" << arg << "' ";
}
}
logstr << "\n"; // FIXME where's flush ?
// try to call linker
return executeToolAndWait(tool, argsBuilder.args, global.params.verbose);
}