1 //===-- llvm/Target/TargetMachine.h - Target Information --------*- C++ -*-===// 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 file defines the TargetMachine and LLVMTargetMachine classes. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_TARGET_TARGETMACHINE_H 15 #define LLVM_TARGET_TARGETMACHINE_H 16 17 #include "llvm/ADT/StringRef.h" 18 #include "llvm/ADT/Triple.h" 19 #include "llvm/IR/DataLayout.h" 20 #include "llvm/Pass.h" 21 #include "llvm/Support/CodeGen.h" 22 #include "llvm/Target/TargetOptions.h" 23 #include <string> 24 25 namespace llvm { 26 27 class GlobalValue; 28 class MachineFunctionInitializer; 29 class Mangler; 30 class MCAsmInfo; 31 class MCContext; 32 class MCInstrInfo; 33 class MCRegisterInfo; 34 class MCSubtargetInfo; 35 class MCSymbol; 36 class raw_pwrite_stream; 37 class PassManagerBuilder; 38 class Target; 39 class TargetIntrinsicInfo; 40 class TargetIRAnalysis; 41 class TargetLoweringObjectFile; 42 class TargetPassConfig; 43 class TargetSubtargetInfo; 44 45 // The old pass manager infrastructure is hidden in a legacy namespace now. 46 namespace legacy { 47 class PassManagerBase; 48 } 49 using legacy::PassManagerBase; 50 51 //===----------------------------------------------------------------------===// 52 /// 53 /// Primary interface to the complete machine description for the target 54 /// machine. All target-specific information should be accessible through this 55 /// interface. 56 /// 57 class TargetMachine { 58 protected: // Can only create subclasses. 59 TargetMachine(const Target &T, StringRef DataLayoutString, 60 const Triple &TargetTriple, StringRef CPU, StringRef FS, 61 const TargetOptions &Options); 62 63 /// The Target that this machine was created for. 64 const Target &TheTarget; 65 66 /// DataLayout for the target: keep ABI type size and alignment. 67 /// 68 /// The DataLayout is created based on the string representation provided 69 /// during construction. It is kept here only to avoid reparsing the string 70 /// but should not really be used during compilation, because it has an 71 /// internal cache that is context specific. 72 const DataLayout DL; 73 74 /// Triple string, CPU name, and target feature strings the TargetMachine 75 /// instance is created with. 76 Triple TargetTriple; 77 std::string TargetCPU; 78 std::string TargetFS; 79 80 Reloc::Model RM = Reloc::Static; 81 CodeModel::Model CMModel = CodeModel::Default; 82 CodeGenOpt::Level OptLevel = CodeGenOpt::Default; 83 84 /// Contains target specific asm information. 85 const MCAsmInfo *AsmInfo; 86 87 const MCRegisterInfo *MRI; 88 const MCInstrInfo *MII; 89 const MCSubtargetInfo *STI; 90 91 unsigned RequireStructuredCFG : 1; 92 unsigned O0WantsFastISel : 1; 93 94 public: 95 const TargetOptions DefaultOptions; 96 mutable TargetOptions Options; 97 98 TargetMachine(const TargetMachine &) = delete; 99 void operator=(const TargetMachine &) = delete; 100 virtual ~TargetMachine(); 101 102 const Target &getTarget() const { return TheTarget; } 103 104 const Triple &getTargetTriple() const { return TargetTriple; } 105 StringRef getTargetCPU() const { return TargetCPU; } 106 StringRef getTargetFeatureString() const { return TargetFS; } 107 108 /// Virtual method implemented by subclasses that returns a reference to that 109 /// target's TargetSubtargetInfo-derived member variable. 110 virtual const TargetSubtargetInfo *getSubtargetImpl(const Function &) const { 111 return nullptr; 112 } 113 virtual TargetLoweringObjectFile *getObjFileLowering() const { 114 return nullptr; 115 } 116 117 /// This method returns a pointer to the specified type of 118 /// TargetSubtargetInfo. In debug builds, it verifies that the object being 119 /// returned is of the correct type. 120 template <typename STC> const STC &getSubtarget(const Function &F) const { 121 return *static_cast<const STC*>(getSubtargetImpl(F)); 122 } 123 124 /// Create a DataLayout. 125 const DataLayout createDataLayout() const { return DL; } 126 127 /// Test if a DataLayout if compatible with the CodeGen for this target. 128 /// 129 /// The LLVM Module owns a DataLayout that is used for the target independent 130 /// optimizations and code generation. This hook provides a target specific 131 /// check on the validity of this DataLayout. 132 bool isCompatibleDataLayout(const DataLayout &Candidate) const { 133 return DL == Candidate; 134 } 135 136 /// Get the pointer size for this target. 137 /// 138 /// This is the only time the DataLayout in the TargetMachine is used. 139 unsigned getPointerSize() const { return DL.getPointerSize(); } 140 141 /// \brief Reset the target options based on the function's attributes. 142 // FIXME: Remove TargetOptions that affect per-function code generation 143 // from TargetMachine. 144 void resetTargetOptions(const Function &F) const; 145 146 /// Return target specific asm information. 147 const MCAsmInfo *getMCAsmInfo() const { return AsmInfo; } 148 149 const MCRegisterInfo *getMCRegisterInfo() const { return MRI; } 150 const MCInstrInfo *getMCInstrInfo() const { return MII; } 151 const MCSubtargetInfo *getMCSubtargetInfo() const { return STI; } 152 153 /// If intrinsic information is available, return it. If not, return null. 154 virtual const TargetIntrinsicInfo *getIntrinsicInfo() const { 155 return nullptr; 156 } 157 158 bool requiresStructuredCFG() const { return RequireStructuredCFG; } 159 void setRequiresStructuredCFG(bool Value) { RequireStructuredCFG = Value; } 160 161 /// Returns the code generation relocation model. The choices are static, PIC, 162 /// and dynamic-no-pic, and target default. 163 Reloc::Model getRelocationModel() const; 164 165 /// Returns the code model. The choices are small, kernel, medium, large, and 166 /// target default. 167 CodeModel::Model getCodeModel() const; 168 169 bool isPositionIndependent() const; 170 171 bool shouldAssumeDSOLocal(const Module &M, const GlobalValue *GV) const; 172 173 /// Returns the TLS model which should be used for the given global variable. 174 TLSModel::Model getTLSModel(const GlobalValue *GV) const; 175 176 /// Returns the optimization level: None, Less, Default, or Aggressive. 177 CodeGenOpt::Level getOptLevel() const; 178 179 /// \brief Overrides the optimization level. 180 void setOptLevel(CodeGenOpt::Level Level); 181 182 void setFastISel(bool Enable) { Options.EnableFastISel = Enable; } 183 bool getO0WantsFastISel() { return O0WantsFastISel; } 184 void setO0WantsFastISel(bool Enable) { O0WantsFastISel = Enable; } 185 186 bool shouldPrintMachineCode() const { return Options.PrintMachineCode; } 187 188 bool getUniqueSectionNames() const { return Options.UniqueSectionNames; } 189 190 /// Return true if data objects should be emitted into their own section, 191 /// corresponds to -fdata-sections. 192 bool getDataSections() const { 193 return Options.DataSections; 194 } 195 196 /// Return true if functions should be emitted into their own section, 197 /// corresponding to -ffunction-sections. 198 bool getFunctionSections() const { 199 return Options.FunctionSections; 200 } 201 202 /// \brief Get a \c TargetIRAnalysis appropriate for the target. 203 /// 204 /// This is used to construct the new pass manager's target IR analysis pass, 205 /// set up appropriately for this target machine. Even the old pass manager 206 /// uses this to answer queries about the IR. 207 virtual TargetIRAnalysis getTargetIRAnalysis(); 208 209 /// Allow the target to modify the pass manager, e.g. by calling 210 /// PassManagerBuilder::addExtension. 211 virtual void adjustPassManager(PassManagerBuilder &) {} 212 213 /// These enums are meant to be passed into addPassesToEmitFile to indicate 214 /// what type of file to emit, and returned by it to indicate what type of 215 /// file could actually be made. 216 enum CodeGenFileType { 217 CGFT_AssemblyFile, 218 CGFT_ObjectFile, 219 CGFT_Null // Do not emit any output. 220 }; 221 222 /// Add passes to the specified pass manager to get the specified file 223 /// emitted. Typically this will involve several steps of code generation. 224 /// This method should return true if emission of this file type is not 225 /// supported, or false on success. 226 virtual bool addPassesToEmitFile( 227 PassManagerBase &, raw_pwrite_stream &, CodeGenFileType, 228 bool /*DisableVerify*/ = true, AnalysisID /*StartBefore*/ = nullptr, 229 AnalysisID /*StartAfter*/ = nullptr, AnalysisID /*StopBefore*/ = nullptr, 230 AnalysisID /*StopAfter*/ = nullptr, 231 MachineFunctionInitializer * /*MFInitializer*/ = nullptr) { 232 return true; 233 } 234 235 /// Add passes to the specified pass manager to get machine code emitted with 236 /// the MCJIT. This method returns true if machine code is not supported. It 237 /// fills the MCContext Ctx pointer which can be used to build custom 238 /// MCStreamer. 239 /// 240 virtual bool addPassesToEmitMC(PassManagerBase &, MCContext *&, 241 raw_pwrite_stream &, 242 bool /*DisableVerify*/ = true) { 243 return true; 244 } 245 246 /// True if subtarget inserts the final scheduling pass on its own. 247 /// 248 /// Branch relaxation, which must happen after block placement, can 249 /// on some targets (e.g. SystemZ) expose additional post-RA 250 /// scheduling opportunities. 251 virtual bool targetSchedulesPostRAScheduling() const { return false; }; 252 253 void getNameWithPrefix(SmallVectorImpl<char> &Name, const GlobalValue *GV, 254 Mangler &Mang, bool MayAlwaysUsePrivate = false) const; 255 MCSymbol *getSymbol(const GlobalValue *GV) const; 256 257 /// True if the target uses physical regs at Prolog/Epilog insertion 258 /// time. If true (most machines), all vregs must be allocated before 259 /// PEI. If false (virtual-register machines), then callee-save register 260 /// spilling and scavenging are not needed or used. 261 virtual bool usesPhysRegsForPEI() const { return true; } 262 }; 263 264 /// This class describes a target machine that is implemented with the LLVM 265 /// target-independent code generator. 266 /// 267 class LLVMTargetMachine : public TargetMachine { 268 protected: // Can only create subclasses. 269 LLVMTargetMachine(const Target &T, StringRef DataLayoutString, 270 const Triple &TargetTriple, StringRef CPU, StringRef FS, 271 const TargetOptions &Options, Reloc::Model RM, 272 CodeModel::Model CM, CodeGenOpt::Level OL); 273 274 void initAsmInfo(); 275 public: 276 /// \brief Get a TargetIRAnalysis implementation for the target. 277 /// 278 /// This analysis will produce a TTI result which uses the common code 279 /// generator to answer queries about the IR. 280 TargetIRAnalysis getTargetIRAnalysis() override; 281 282 /// Create a pass configuration object to be used by addPassToEmitX methods 283 /// for generating a pipeline of CodeGen passes. 284 virtual TargetPassConfig *createPassConfig(PassManagerBase &PM); 285 286 /// Add passes to the specified pass manager to get the specified file 287 /// emitted. Typically this will involve several steps of code generation. 288 bool addPassesToEmitFile( 289 PassManagerBase &PM, raw_pwrite_stream &Out, CodeGenFileType FileType, 290 bool DisableVerify = true, AnalysisID StartBefore = nullptr, 291 AnalysisID StartAfter = nullptr, AnalysisID StopBefore = nullptr, 292 AnalysisID StopAfter = nullptr, 293 MachineFunctionInitializer *MFInitializer = nullptr) override; 294 295 /// Add passes to the specified pass manager to get machine code emitted with 296 /// the MCJIT. This method returns true if machine code is not supported. It 297 /// fills the MCContext Ctx pointer which can be used to build custom 298 /// MCStreamer. 299 bool addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx, 300 raw_pwrite_stream &OS, 301 bool DisableVerify = true) override; 302 }; 303 304 } // end namespace llvm 305 306 #endif // LLVM_TARGET_TARGETMACHINE_H 307