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 Mangler; 29 class MCAsmInfo; 30 class MCContext; 31 class MCInstrInfo; 32 class MCRegisterInfo; 33 class MCSubtargetInfo; 34 class MCSymbol; 35 class raw_pwrite_stream; 36 class PassManagerBuilder; 37 class Target; 38 class TargetIntrinsicInfo; 39 class TargetIRAnalysis; 40 class TargetLoweringObjectFile; 41 class TargetPassConfig; 42 class TargetSubtargetInfo; 43 44 // The old pass manager infrastructure is hidden in a legacy namespace now. 45 namespace legacy { 46 class PassManagerBase; 47 } 48 using legacy::PassManagerBase; 49 50 //===----------------------------------------------------------------------===// 51 /// 52 /// Primary interface to the complete machine description for the target 53 /// machine. All target-specific information should be accessible through this 54 /// interface. 55 /// 56 class TargetMachine { 57 protected: // Can only create subclasses. 58 TargetMachine(const Target &T, StringRef DataLayoutString, 59 const Triple &TargetTriple, StringRef CPU, StringRef FS, 60 const TargetOptions &Options); 61 62 /// The Target that this machine was created for. 63 const Target &TheTarget; 64 65 /// DataLayout for the target: keep ABI type size and alignment. 66 /// 67 /// The DataLayout is created based on the string representation provided 68 /// during construction. It is kept here only to avoid reparsing the string 69 /// but should not really be used during compilation, because it has an 70 /// internal cache that is context specific. 71 const DataLayout DL; 72 73 /// Triple string, CPU name, and target feature strings the TargetMachine 74 /// instance is created with. 75 Triple TargetTriple; 76 std::string TargetCPU; 77 std::string TargetFS; 78 79 Reloc::Model RM = Reloc::Static; 80 CodeModel::Model CMModel = CodeModel::Default; 81 CodeGenOpt::Level OptLevel = CodeGenOpt::Default; 82 83 /// Contains target specific asm information. 84 const MCAsmInfo *AsmInfo; 85 86 const MCRegisterInfo *MRI; 87 const MCInstrInfo *MII; 88 const MCSubtargetInfo *STI; 89 90 unsigned RequireStructuredCFG : 1; 91 unsigned O0WantsFastISel : 1; 92 93 public: 94 const TargetOptions DefaultOptions; 95 mutable TargetOptions Options; 96 97 TargetMachine(const TargetMachine &) = delete; 98 void operator=(const TargetMachine &) = delete; 99 virtual ~TargetMachine(); 100 101 const Target &getTarget() const { return TheTarget; } 102 103 const Triple &getTargetTriple() const { return TargetTriple; } 104 StringRef getTargetCPU() const { return TargetCPU; } 105 StringRef getTargetFeatureString() const { return TargetFS; } 106 107 /// Virtual method implemented by subclasses that returns a reference to that 108 /// target's TargetSubtargetInfo-derived member variable. 109 virtual const TargetSubtargetInfo *getSubtargetImpl(const Function &) const { 110 return nullptr; 111 } 112 virtual TargetLoweringObjectFile *getObjFileLowering() const { 113 return nullptr; 114 } 115 116 /// This method returns a pointer to the specified type of 117 /// TargetSubtargetInfo. In debug builds, it verifies that the object being 118 /// returned is of the correct type. 119 template <typename STC> const STC &getSubtarget(const Function &F) const { 120 return *static_cast<const STC*>(getSubtargetImpl(F)); 121 } 122 123 /// Create a DataLayout. 124 const DataLayout createDataLayout() const { return DL; } 125 126 /// Test if a DataLayout if compatible with the CodeGen for this target. 127 /// 128 /// The LLVM Module owns a DataLayout that is used for the target independent 129 /// optimizations and code generation. This hook provides a target specific 130 /// check on the validity of this DataLayout. 131 bool isCompatibleDataLayout(const DataLayout &Candidate) const { 132 return DL == Candidate; 133 } 134 135 /// Get the pointer size for this target. 136 /// 137 /// This is the only time the DataLayout in the TargetMachine is used. 138 unsigned getPointerSize() const { return DL.getPointerSize(); } 139 140 /// \brief Reset the target options based on the function's attributes. 141 // FIXME: Remove TargetOptions that affect per-function code generation 142 // from TargetMachine. 143 void resetTargetOptions(const Function &F) const; 144 145 /// Return target specific asm information. 146 const MCAsmInfo *getMCAsmInfo() const { return AsmInfo; } 147 148 const MCRegisterInfo *getMCRegisterInfo() const { return MRI; } 149 const MCInstrInfo *getMCInstrInfo() const { return MII; } 150 const MCSubtargetInfo *getMCSubtargetInfo() const { return STI; } 151 152 /// If intrinsic information is available, return it. If not, return null. 153 virtual const TargetIntrinsicInfo *getIntrinsicInfo() const { 154 return nullptr; 155 } 156 157 bool requiresStructuredCFG() const { return RequireStructuredCFG; } 158 void setRequiresStructuredCFG(bool Value) { RequireStructuredCFG = Value; } 159 160 /// Returns the code generation relocation model. The choices are static, PIC, 161 /// and dynamic-no-pic, and target default. 162 Reloc::Model getRelocationModel() const; 163 164 /// Returns the code model. The choices are small, kernel, medium, large, and 165 /// target default. 166 CodeModel::Model getCodeModel() const; 167 168 bool isPositionIndependent() const; 169 170 bool shouldAssumeDSOLocal(const Module &M, const GlobalValue *GV) const; 171 172 /// Returns the TLS model which should be used for the given global variable. 173 TLSModel::Model getTLSModel(const GlobalValue *GV) const; 174 175 /// Returns the optimization level: None, Less, Default, or Aggressive. 176 CodeGenOpt::Level getOptLevel() const; 177 178 /// \brief Overrides the optimization level. 179 void setOptLevel(CodeGenOpt::Level Level); 180 181 void setFastISel(bool Enable) { Options.EnableFastISel = Enable; } 182 bool getO0WantsFastISel() { return O0WantsFastISel; } 183 void setO0WantsFastISel(bool Enable) { O0WantsFastISel = Enable; } 184 185 bool shouldPrintMachineCode() const { return Options.PrintMachineCode; } 186 187 bool getUniqueSectionNames() const { return Options.UniqueSectionNames; } 188 189 /// Return true if data objects should be emitted into their own section, 190 /// corresponds to -fdata-sections. 191 bool getDataSections() const { 192 return Options.DataSections; 193 } 194 195 /// Return true if functions should be emitted into their own section, 196 /// corresponding to -ffunction-sections. 197 bool getFunctionSections() const { 198 return Options.FunctionSections; 199 } 200 201 /// \brief Get a \c TargetIRAnalysis appropriate for the target. 202 /// 203 /// This is used to construct the new pass manager's target IR analysis pass, 204 /// set up appropriately for this target machine. Even the old pass manager 205 /// uses this to answer queries about the IR. 206 virtual TargetIRAnalysis getTargetIRAnalysis(); 207 208 /// Allow the target to modify the pass manager, e.g. by calling 209 /// PassManagerBuilder::addExtension. 210 virtual void adjustPassManager(PassManagerBuilder &) {} 211 212 /// These enums are meant to be passed into addPassesToEmitFile to indicate 213 /// what type of file to emit, and returned by it to indicate what type of 214 /// file could actually be made. 215 enum CodeGenFileType { 216 CGFT_AssemblyFile, 217 CGFT_ObjectFile, 218 CGFT_Null // Do not emit any output. 219 }; 220 221 /// Add passes to the specified pass manager to get the specified file 222 /// emitted. Typically this will involve several steps of code generation. 223 /// This method should return true if emission of this file type is not 224 /// supported, or false on success. 225 virtual bool addPassesToEmitFile( 226 PassManagerBase &, raw_pwrite_stream &, CodeGenFileType, 227 bool /*DisableVerify*/ = true, AnalysisID /*StartBefore*/ = nullptr, 228 AnalysisID /*StartAfter*/ = nullptr, AnalysisID /*StopBefore*/ = nullptr, 229 AnalysisID /*StopAfter*/ = nullptr) { 230 return true; 231 } 232 233 /// Add passes to the specified pass manager to get machine code emitted with 234 /// the MCJIT. This method returns true if machine code is not supported. It 235 /// fills the MCContext Ctx pointer which can be used to build custom 236 /// MCStreamer. 237 /// 238 virtual bool addPassesToEmitMC(PassManagerBase &, MCContext *&, 239 raw_pwrite_stream &, 240 bool /*DisableVerify*/ = true) { 241 return true; 242 } 243 244 /// True if subtarget inserts the final scheduling pass on its own. 245 /// 246 /// Branch relaxation, which must happen after block placement, can 247 /// on some targets (e.g. SystemZ) expose additional post-RA 248 /// scheduling opportunities. 249 virtual bool targetSchedulesPostRAScheduling() const { return false; }; 250 251 void getNameWithPrefix(SmallVectorImpl<char> &Name, const GlobalValue *GV, 252 Mangler &Mang, bool MayAlwaysUsePrivate = false) const; 253 MCSymbol *getSymbol(const GlobalValue *GV) const; 254 255 /// True if the target uses physical regs at Prolog/Epilog insertion 256 /// time. If true (most machines), all vregs must be allocated before 257 /// PEI. If false (virtual-register machines), then callee-save register 258 /// spilling and scavenging are not needed or used. 259 virtual bool usesPhysRegsForPEI() const { return true; } 260 }; 261 262 /// This class describes a target machine that is implemented with the LLVM 263 /// target-independent code generator. 264 /// 265 class LLVMTargetMachine : public TargetMachine { 266 protected: // Can only create subclasses. 267 LLVMTargetMachine(const Target &T, StringRef DataLayoutString, 268 const Triple &TargetTriple, StringRef CPU, StringRef FS, 269 const TargetOptions &Options, Reloc::Model RM, 270 CodeModel::Model CM, CodeGenOpt::Level OL); 271 272 void initAsmInfo(); 273 public: 274 /// \brief Get a TargetIRAnalysis implementation for the target. 275 /// 276 /// This analysis will produce a TTI result which uses the common code 277 /// generator to answer queries about the IR. 278 TargetIRAnalysis getTargetIRAnalysis() override; 279 280 /// Create a pass configuration object to be used by addPassToEmitX methods 281 /// for generating a pipeline of CodeGen passes. 282 virtual TargetPassConfig *createPassConfig(PassManagerBase &PM); 283 284 /// Add passes to the specified pass manager to get the specified file 285 /// emitted. Typically this will involve several steps of code generation. 286 bool addPassesToEmitFile( 287 PassManagerBase &PM, raw_pwrite_stream &Out, CodeGenFileType FileType, 288 bool DisableVerify = true, AnalysisID StartBefore = nullptr, 289 AnalysisID StartAfter = nullptr, AnalysisID StopBefore = nullptr, 290 AnalysisID StopAfter = nullptr) override; 291 292 /// Add passes to the specified pass manager to get machine code emitted with 293 /// the MCJIT. This method returns true if machine code is not supported. It 294 /// fills the MCContext Ctx pointer which can be used to build custom 295 /// MCStreamer. 296 bool addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx, 297 raw_pwrite_stream &OS, 298 bool DisableVerify = true) override; 299 300 /// Returns true if the target is expected to pass all machine verifier 301 /// checks. This is a stopgap measure to fix targets one by one. We will 302 /// remove this at some point and always enable the verifier when 303 /// EXPENSIVE_CHECKS is enabled. 304 virtual bool isMachineVerifierClean() const { return true; } 305 306 /// \brief Adds an AsmPrinter pass to the pipeline that prints assembly or 307 /// machine code from the MI representation. 308 bool addAsmPrinter(PassManagerBase &PM, raw_pwrite_stream &Out, 309 CodeGenFileType FileTYpe, MCContext &Context); 310 }; 311 312 } // end namespace llvm 313 314 #endif // LLVM_TARGET_TARGETMACHINE_H 315