95 lines · cpp
1//===-- TargetSelect.cpp - Target Chooser Code ----------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// This just asks the TargetRegistry for the appropriate target to use, and10// allows the user to specify a specific one on the commandline with -march=x,11// -mcpu=y, and -mattr=a,-b,+c. Clients should initialize targets prior to12// calling selectTarget().13//14//===----------------------------------------------------------------------===//15 16#include "llvm/ExecutionEngine/ExecutionEngine.h"17#include "llvm/IR/Module.h"18#include "llvm/MC/TargetRegistry.h"19#include "llvm/Target/TargetMachine.h"20#include "llvm/TargetParser/Host.h"21#include "llvm/TargetParser/SubtargetFeature.h"22#include "llvm/TargetParser/Triple.h"23 24using namespace llvm;25 26TargetMachine *EngineBuilder::selectTarget() {27 Triple TT;28 29 // MCJIT can generate code for remote targets, but the old JIT and Interpreter30 // must use the host architecture.31 if (WhichEngine != EngineKind::Interpreter && M)32 TT = M->getTargetTriple();33 34 return selectTarget(TT, MArch, MCPU, MAttrs);35}36 37/// selectTarget - Pick a target either via -march or by guessing the native38/// arch. Add any CPU features specified via -mcpu or -mattr.39TargetMachine *EngineBuilder::selectTarget(const Triple &TargetTriple,40 StringRef MArch,41 StringRef MCPU,42 const SmallVectorImpl<std::string>& MAttrs) {43 Triple TheTriple(TargetTriple);44 if (TheTriple.getTriple().empty())45 TheTriple.setTriple(sys::getProcessTriple());46 47 // Adjust the triple to match what the user requested.48 const Target *TheTarget = nullptr;49 if (!MArch.empty()) {50 auto I = find_if(TargetRegistry::targets(),51 [&](const Target &T) { return MArch == T.getName(); });52 53 if (I == TargetRegistry::targets().end()) {54 if (ErrorStr)55 *ErrorStr = "No available targets are compatible with this -march, "56 "see -version for the available targets.\n";57 return nullptr;58 }59 60 TheTarget = &*I;61 62 // Adjust the triple to match (if known), otherwise stick with the63 // requested/host triple.64 Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);65 if (Type != Triple::UnknownArch)66 TheTriple.setArch(Type);67 } else {68 std::string Error;69 TheTarget = TargetRegistry::lookupTarget(TheTriple, Error);70 if (!TheTarget) {71 if (ErrorStr)72 *ErrorStr = Error;73 return nullptr;74 }75 }76 77 // Package up features to be passed to target/subtarget78 std::string FeaturesStr;79 if (!MAttrs.empty()) {80 SubtargetFeatures Features;81 for (unsigned i = 0; i != MAttrs.size(); ++i)82 Features.AddFeature(MAttrs[i]);83 FeaturesStr = Features.getString();84 }85 86 // Allocate a target...87 TargetMachine *Target = TheTarget->createTargetMachine(88 TheTriple, MCPU, FeaturesStr, Options, RelocModel, CMModel, OptLevel,89 /*JIT=*/true);90 Target->Options.EmulatedTLS = EmulatedTLS;91 92 assert(Target && "Could not allocate target machine!");93 return Target;94}95