1//===-- TargetSelect.cpp - Target Chooser Code ----------------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This just asks the TargetRegistry for the appropriate target to use, and 11// allows the user to specify a specific one on the commandline with -march=x, 12// -mcpu=y, and -mattr=a,-b,+c. Clients should initialize targets prior to 13// calling selectTarget(). 14// 15//===----------------------------------------------------------------------===// 16 17#include "llvm/ExecutionEngine/ExecutionEngine.h" 18#include "llvm/ADT/Triple.h" 19#include "llvm/IR/Module.h" 20#include "llvm/MC/SubtargetFeature.h" 21#include "llvm/Support/CommandLine.h" 22#include "llvm/Support/Host.h" 23#include "llvm/Support/TargetRegistry.h" 24#include "llvm/Target/TargetMachine.h" 25 26using namespace llvm; 27 28TargetMachine *EngineBuilder::selectTarget() { 29 Triple TT; 30 31 // MCJIT can generate code for remote targets, but the old JIT and Interpreter 32 // must use the host architecture. 33 if (WhichEngine != EngineKind::Interpreter && M) 34 TT.setTriple(M->getTargetTriple()); 35 36 return selectTarget(TT, MArch, MCPU, MAttrs); 37} 38 39/// selectTarget - Pick a target either via -march or by guessing the native 40/// arch. Add any CPU features specified via -mcpu or -mattr. 41TargetMachine *EngineBuilder::selectTarget(const Triple &TargetTriple, 42 StringRef MArch, 43 StringRef MCPU, 44 const SmallVectorImpl<std::string>& MAttrs) { 45 Triple TheTriple(TargetTriple); 46 if (TheTriple.getTriple().empty()) 47 TheTriple.setTriple(sys::getProcessTriple()); 48 49 // Adjust the triple to match what the user requested. 50 const Target *TheTarget = nullptr; 51 if (!MArch.empty()) { 52 auto I = std::find_if( 53 TargetRegistry::targets().begin(), TargetRegistry::targets().end(), 54 [&](const Target &T) { return MArch == T.getName(); }); 55 56 if (I == TargetRegistry::targets().end()) { 57 if (ErrorStr) 58 *ErrorStr = "No available targets are compatible with this -march, " 59 "see -version for the available targets.\n"; 60 return nullptr; 61 } 62 63 TheTarget = &*I; 64 65 // Adjust the triple to match (if known), otherwise stick with the 66 // requested/host triple. 67 Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch); 68 if (Type != Triple::UnknownArch) 69 TheTriple.setArch(Type); 70 } else { 71 std::string Error; 72 TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Error); 73 if (!TheTarget) { 74 if (ErrorStr) 75 *ErrorStr = Error; 76 return nullptr; 77 } 78 } 79 80 // Package up features to be passed to target/subtarget 81 std::string FeaturesStr; 82 if (!MAttrs.empty()) { 83 SubtargetFeatures Features; 84 for (unsigned i = 0; i != MAttrs.size(); ++i) 85 Features.AddFeature(MAttrs[i]); 86 FeaturesStr = Features.getString(); 87 } 88 89 // FIXME: non-iOS ARM FastISel is broken with MCJIT. 90 if (TheTriple.getArch() == Triple::arm && 91 !TheTriple.isiOS() && 92 OptLevel == CodeGenOpt::None) { 93 OptLevel = CodeGenOpt::Less; 94 } 95 96 // Allocate a target... 97 TargetMachine *Target = TheTarget->createTargetMachine(TheTriple.getTriple(), 98 MCPU, FeaturesStr, 99 Options, 100 RelocModel, CMModel, 101 OptLevel); 102 assert(Target && "Could not allocate target machine!"); 103 return Target; 104} 105