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/Module.h" 19 #include "llvm/ADT/Triple.h" 20 #include "llvm/MC/SubtargetFeature.h" 21 #include "llvm/Target/TargetMachine.h" 22 #include "llvm/Support/CommandLine.h" 23 #include "llvm/Support/Host.h" 24 #include "llvm/Support/TargetRegistry.h" 25 26 using namespace llvm; 27 28 TargetMachine *EngineBuilder::selectTarget() { 29 Triple TT(LLVM_HOSTTRIPLE); 30 return selectTarget(TT, MArch, MCPU, MAttrs); 31 } 32 33 /// selectTarget - Pick a target either via -march or by guessing the native 34 /// arch. Add any CPU features specified via -mcpu or -mattr. 35 TargetMachine *EngineBuilder::selectTarget(const Triple &TargetTriple, 36 StringRef MArch, 37 StringRef MCPU, 38 const SmallVectorImpl<std::string>& MAttrs) { 39 Triple TheTriple(TargetTriple); 40 if (TheTriple.getTriple().empty()) 41 TheTriple.setTriple(sys::getDefaultTargetTriple()); 42 43 // Adjust the triple to match what the user requested. 44 const Target *TheTarget = 0; 45 if (!MArch.empty()) { 46 for (TargetRegistry::iterator it = TargetRegistry::begin(), 47 ie = TargetRegistry::end(); it != ie; ++it) { 48 if (MArch == it->getName()) { 49 TheTarget = &*it; 50 break; 51 } 52 } 53 54 if (!TheTarget) { 55 if (ErrorStr) 56 *ErrorStr = "No available targets are compatible with this -march, " 57 "see -version for the available targets.\n"; 58 return 0; 59 } 60 61 // Adjust the triple to match (if known), otherwise stick with the 62 // requested/host triple. 63 Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch); 64 if (Type != Triple::UnknownArch) 65 TheTriple.setArch(Type); 66 } else { 67 std::string Error; 68 TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Error); 69 if (TheTarget == 0) { 70 if (ErrorStr) 71 *ErrorStr = Error; 72 return 0; 73 } 74 } 75 76 // Package up features to be passed to target/subtarget 77 std::string FeaturesStr; 78 if (!MAttrs.empty()) { 79 SubtargetFeatures Features; 80 for (unsigned i = 0; i != MAttrs.size(); ++i) 81 Features.AddFeature(MAttrs[i]); 82 FeaturesStr = Features.getString(); 83 } 84 85 // Allocate a target... 86 TargetMachine *Target = TheTarget->createTargetMachine(TheTriple.getTriple(), 87 MCPU, FeaturesStr, 88 Options, 89 RelocModel, CMModel, 90 OptLevel); 91 assert(Target && "Could not allocate target machine!"); 92 return Target; 93 } 94