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