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//===-- TargetSelect.cpp - Target Chooser Code ----------------------------===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// This just asks the TargetRegistry for the appropriate target to use, and
// allows the user to specify a specific one on the commandline with -march=x,
// -mcpu=y, and -mattr=a,-b,+c. Clients should initialize targets prior to
// calling selectTarget().
#include "llvm/ADT/Triple.h"
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/IR/Module.h"
#include "llvm/MC/SubtargetFeature.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Target/TargetMachine.h"
using namespace llvm;
TargetMachine *EngineBuilder::selectTarget() {
Triple TT;
// MCJIT can generate code for remote targets, but the old JIT and Interpreter
// must use the host architecture.
if (WhichEngine != EngineKind::Interpreter && M)
return selectTarget(TT, MArch, MCPU, MAttrs);
/// selectTarget - Pick a target either via -march or by guessing the native
/// arch. Add any CPU features specified via -mcpu or -mattr.
TargetMachine *EngineBuilder::selectTarget(const Triple &TargetTriple,
StringRef MArch,
StringRef MCPU,
const SmallVectorImpl<std::string>& MAttrs) {
Triple TheTriple(TargetTriple);
if (TheTriple.getTriple().empty())
// Adjust the triple to match what the user requested.
const Target *TheTarget = nullptr;
if (!MArch.empty()) {
auto I = find_if(TargetRegistry::targets(),
[&](const Target &T) { return MArch == T.getName(); });
if (I == TargetRegistry::targets().end()) {
if (ErrorStr)
*ErrorStr = "No available targets are compatible with this -march, "
"see -version for the available targets.\n";
return nullptr;
TheTarget = &*I;
// Adjust the triple to match (if known), otherwise stick with the
// requested/host triple.
Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
if (Type != Triple::UnknownArch)
} else {
std::string Error;
TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Error);
if (!TheTarget) {
if (ErrorStr)
*ErrorStr = Error;
return nullptr;
// Package up features to be passed to target/subtarget
std::string FeaturesStr;
if (!MAttrs.empty()) {
SubtargetFeatures Features;
for (unsigned i = 0; i != MAttrs.size(); ++i)
FeaturesStr = Features.getString();
// FIXME: non-iOS ARM FastISel is broken with MCJIT.
if (TheTriple.getArch() == Triple::arm &&
!TheTriple.isiOS() &&
OptLevel == CodeGenOpt::None) {
OptLevel = CodeGenOpt::Less;
// Allocate a target...
TargetMachine *Target =
TheTarget->createTargetMachine(TheTriple.getTriple(), MCPU, FeaturesStr,
Options, RelocModel, CMModel, OptLevel,
/*JIT*/ true);
Target->Options.EmulatedTLS = EmulatedTLS;
Target->Options.ExplicitEmulatedTLS = true;
assert(Target && "Could not allocate target machine!");
return Target;