1 //===-- llvm/CodeGen/AsmPrinter.h - AsmPrinter Framework --------*- 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 contains a class to be used as the base class for target specific 11 // asm writers. This class primarily handles common functionality used by 12 // all asm writers. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #ifndef LLVM_CODEGEN_ASMPRINTER_H 17 #define LLVM_CODEGEN_ASMPRINTER_H 18 19 #include "llvm/CodeGen/MachineFunctionPass.h" 20 #include "llvm/IR/InlineAsm.h" 21 #include "llvm/Support/DataTypes.h" 22 #include "llvm/Support/ErrorHandling.h" 23 24 namespace llvm { 25 class BlockAddress; 26 class GCStrategy; 27 class Constant; 28 class ConstantArray; 29 class GCMetadataPrinter; 30 class GlobalValue; 31 class GlobalVariable; 32 class MachineBasicBlock; 33 class MachineFunction; 34 class MachineInstr; 35 class MachineLocation; 36 class MachineLoopInfo; 37 class MachineLoop; 38 class MachineConstantPoolValue; 39 class MachineJumpTableInfo; 40 class MachineModuleInfo; 41 class MCAsmInfo; 42 class MCCFIInstruction; 43 class MCContext; 44 class MCSection; 45 class MCStreamer; 46 class MCSymbol; 47 class MDNode; 48 class DwarfDebug; 49 class DwarfException; 50 class Mangler; 51 class TargetLoweringObjectFile; 52 class DataLayout; 53 class TargetMachine; 54 55 /// AsmPrinter - This class is intended to be used as a driving class for all 56 /// asm writers. 57 class AsmPrinter : public MachineFunctionPass { 58 public: 59 /// Target machine description. 60 /// 61 TargetMachine &TM; 62 63 /// Target Asm Printer information. 64 /// 65 const MCAsmInfo *MAI; 66 67 /// OutContext - This is the context for the output file that we are 68 /// streaming. This owns all of the global MC-related objects for the 69 /// generated translation unit. 70 MCContext &OutContext; 71 72 /// OutStreamer - This is the MCStreamer object for the file we are 73 /// generating. This contains the transient state for the current 74 /// translation unit that we are generating (such as the current section 75 /// etc). 76 MCStreamer &OutStreamer; 77 78 /// The current machine function. 79 const MachineFunction *MF; 80 81 /// MMI - This is a pointer to the current MachineModuleInfo. 82 MachineModuleInfo *MMI; 83 84 /// Name-mangler for global names. 85 /// 86 Mangler *Mang; 87 88 /// The symbol for the current function. This is recalculated at the 89 /// beginning of each call to runOnMachineFunction(). 90 /// 91 MCSymbol *CurrentFnSym; 92 93 /// The symbol used to represent the start of the current function for the 94 /// purpose of calculating its size (e.g. using the .size directive). By 95 /// default, this is equal to CurrentFnSym. 96 MCSymbol *CurrentFnSymForSize; 97 98 private: 99 // GCMetadataPrinters - The garbage collection metadata printer table. 100 void *GCMetadataPrinters; // Really a DenseMap. 101 102 /// VerboseAsm - Emit comments in assembly output if this is true. 103 /// 104 bool VerboseAsm; 105 static char ID; 106 107 /// If VerboseAsm is set, a pointer to the loop info for this 108 /// function. 109 MachineLoopInfo *LI; 110 111 /// DD - If the target supports dwarf debug info, this pointer is non-null. 112 DwarfDebug *DD; 113 114 /// DE - If the target supports dwarf exception info, this pointer is 115 /// non-null. 116 DwarfException *DE; 117 118 protected: 119 explicit AsmPrinter(TargetMachine &TM, MCStreamer &Streamer); 120 121 public: 122 virtual ~AsmPrinter(); 123 124 const DwarfDebug *getDwarfDebug() const { return DD; } 125 126 /// isVerbose - Return true if assembly output should contain comments. 127 /// 128 bool isVerbose() const { return VerboseAsm; } 129 130 /// getFunctionNumber - Return a unique ID for the current function. 131 /// 132 unsigned getFunctionNumber() const; 133 134 /// getObjFileLowering - Return information about object file lowering. 135 const TargetLoweringObjectFile &getObjFileLowering() const; 136 137 /// getDataLayout - Return information about data layout. 138 const DataLayout &getDataLayout() const; 139 140 /// getTargetTriple - Return the target triple string. 141 StringRef getTargetTriple() const; 142 143 /// getCurrentSection() - Return the current section we are emitting to. 144 const MCSection *getCurrentSection() const; 145 146 147 //===------------------------------------------------------------------===// 148 // MachineFunctionPass Implementation. 149 //===------------------------------------------------------------------===// 150 151 /// getAnalysisUsage - Record analysis usage. 152 /// 153 void getAnalysisUsage(AnalysisUsage &AU) const; 154 155 /// doInitialization - Set up the AsmPrinter when we are working on a new 156 /// module. If your pass overrides this, it must make sure to explicitly 157 /// call this implementation. 158 bool doInitialization(Module &M); 159 160 /// doFinalization - Shut down the asmprinter. If you override this in your 161 /// pass, you must make sure to call it explicitly. 162 bool doFinalization(Module &M); 163 164 /// runOnMachineFunction - Emit the specified function out to the 165 /// OutStreamer. 166 virtual bool runOnMachineFunction(MachineFunction &MF) { 167 SetupMachineFunction(MF); 168 EmitFunctionHeader(); 169 EmitFunctionBody(); 170 return false; 171 } 172 173 //===------------------------------------------------------------------===// 174 // Coarse grained IR lowering routines. 175 //===------------------------------------------------------------------===// 176 177 /// SetupMachineFunction - This should be called when a new MachineFunction 178 /// is being processed from runOnMachineFunction. 179 void SetupMachineFunction(MachineFunction &MF); 180 181 /// EmitFunctionHeader - This method emits the header for the current 182 /// function. 183 void EmitFunctionHeader(); 184 185 /// EmitFunctionBody - This method emits the body and trailer for a 186 /// function. 187 void EmitFunctionBody(); 188 189 void emitPrologLabel(const MachineInstr &MI); 190 191 enum CFIMoveType { 192 CFI_M_None, 193 CFI_M_EH, 194 CFI_M_Debug 195 }; 196 CFIMoveType needsCFIMoves(); 197 198 bool needsSEHMoves(); 199 200 /// needsRelocationsForDwarfStringPool - Specifies whether the object format 201 /// expects to use relocations to refer to debug entries. Alternatively we 202 /// emit section offsets in bytes from the start of the string pool. 203 bool needsRelocationsForDwarfStringPool() const; 204 205 /// EmitConstantPool - Print to the current output stream assembly 206 /// representations of the constants in the constant pool MCP. This is 207 /// used to print out constants which have been "spilled to memory" by 208 /// the code generator. 209 /// 210 virtual void EmitConstantPool(); 211 212 /// EmitJumpTableInfo - Print assembly representations of the jump tables 213 /// used by the current function to the current output stream. 214 /// 215 void EmitJumpTableInfo(); 216 217 /// EmitGlobalVariable - Emit the specified global variable to the .s file. 218 virtual void EmitGlobalVariable(const GlobalVariable *GV); 219 220 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a 221 /// special global used by LLVM. If so, emit it and return true, otherwise 222 /// do nothing and return false. 223 bool EmitSpecialLLVMGlobal(const GlobalVariable *GV); 224 225 /// EmitAlignment - Emit an alignment directive to the specified power of 226 /// two boundary. For example, if you pass in 3 here, you will get an 8 227 /// byte alignment. If a global value is specified, and if that global has 228 /// an explicit alignment requested, it will override the alignment request 229 /// if required for correctness. 230 /// 231 void EmitAlignment(unsigned NumBits, const GlobalValue *GV = 0) const; 232 233 /// EmitBasicBlockStart - This method prints the label for the specified 234 /// MachineBasicBlock, an alignment (if present) and a comment describing 235 /// it if appropriate. 236 void EmitBasicBlockStart(const MachineBasicBlock *MBB) const; 237 238 /// \brief Print a general LLVM constant to the .s file. 239 void EmitGlobalConstant(const Constant *CV); 240 241 242 //===------------------------------------------------------------------===// 243 // Overridable Hooks 244 //===------------------------------------------------------------------===// 245 246 // Targets can, or in the case of EmitInstruction, must implement these to 247 // customize output. 248 249 /// EmitStartOfAsmFile - This virtual method can be overridden by targets 250 /// that want to emit something at the start of their file. 251 virtual void EmitStartOfAsmFile(Module &) {} 252 253 /// EmitEndOfAsmFile - This virtual method can be overridden by targets that 254 /// want to emit something at the end of their file. 255 virtual void EmitEndOfAsmFile(Module &) {} 256 257 /// EmitFunctionBodyStart - Targets can override this to emit stuff before 258 /// the first basic block in the function. 259 virtual void EmitFunctionBodyStart() {} 260 261 /// EmitFunctionBodyEnd - Targets can override this to emit stuff after 262 /// the last basic block in the function. 263 virtual void EmitFunctionBodyEnd() {} 264 265 /// EmitInstruction - Targets should implement this to emit instructions. 266 virtual void EmitInstruction(const MachineInstr *) { 267 llvm_unreachable("EmitInstruction not implemented"); 268 } 269 270 virtual void EmitFunctionEntryLabel(); 271 272 virtual void EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV); 273 274 /// EmitXXStructor - Targets can override this to change how global 275 /// constants that are part of a C++ static/global constructor list are 276 /// emitted. 277 virtual void EmitXXStructor(const Constant *CV) { 278 EmitGlobalConstant(CV); 279 } 280 281 /// isBlockOnlyReachableByFallthough - Return true if the basic block has 282 /// exactly one predecessor and the control transfer mechanism between 283 /// the predecessor and this block is a fall-through. 284 virtual bool 285 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const; 286 287 //===------------------------------------------------------------------===// 288 // Symbol Lowering Routines. 289 //===------------------------------------------------------------------===// 290 public: 291 292 /// GetTempSymbol - Return the MCSymbol corresponding to the assembler 293 /// temporary label with the specified stem and unique ID. 294 MCSymbol *GetTempSymbol(StringRef Name, unsigned ID) const; 295 296 /// GetTempSymbol - Return an assembler temporary label with the specified 297 /// stem. 298 MCSymbol *GetTempSymbol(StringRef Name) const; 299 300 301 /// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with 302 /// global value name as its base, with the specified suffix, and where the 303 /// symbol is forced to have private linkage if ForcePrivate is true. 304 MCSymbol *GetSymbolWithGlobalValueBase(const GlobalValue *GV, 305 StringRef Suffix, 306 bool ForcePrivate = true) const; 307 308 /// GetExternalSymbolSymbol - Return the MCSymbol for the specified 309 /// ExternalSymbol. 310 MCSymbol *GetExternalSymbolSymbol(StringRef Sym) const; 311 312 /// GetCPISymbol - Return the symbol for the specified constant pool entry. 313 MCSymbol *GetCPISymbol(unsigned CPID) const; 314 315 /// GetJTISymbol - Return the symbol for the specified jump table entry. 316 MCSymbol *GetJTISymbol(unsigned JTID, bool isLinkerPrivate = false) const; 317 318 /// GetJTSetSymbol - Return the symbol for the specified jump table .set 319 /// FIXME: privatize to AsmPrinter. 320 MCSymbol *GetJTSetSymbol(unsigned UID, unsigned MBBID) const; 321 322 /// GetBlockAddressSymbol - Return the MCSymbol used to satisfy BlockAddress 323 /// uses of the specified basic block. 324 MCSymbol *GetBlockAddressSymbol(const BlockAddress *BA) const; 325 MCSymbol *GetBlockAddressSymbol(const BasicBlock *BB) const; 326 327 //===------------------------------------------------------------------===// 328 // Emission Helper Routines. 329 //===------------------------------------------------------------------===// 330 public: 331 /// printOffset - This is just convenient handler for printing offsets. 332 void printOffset(int64_t Offset, raw_ostream &OS) const; 333 334 /// EmitInt8 - Emit a byte directive and value. 335 /// 336 void EmitInt8(int Value) const; 337 338 /// EmitInt16 - Emit a short directive and value. 339 /// 340 void EmitInt16(int Value) const; 341 342 /// EmitInt32 - Emit a long directive and value. 343 /// 344 void EmitInt32(int Value) const; 345 346 /// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size 347 /// in bytes of the directive is specified by Size and Hi/Lo specify the 348 /// labels. This implicitly uses .set if it is available. 349 void EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo, 350 unsigned Size) const; 351 352 /// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo" 353 /// where the size in bytes of the directive is specified by Size and Hi/Lo 354 /// specify the labels. This implicitly uses .set if it is available. 355 void EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset, 356 const MCSymbol *Lo, unsigned Size) const; 357 358 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset" 359 /// where the size in bytes of the directive is specified by Size and Label 360 /// specifies the label. This implicitly uses .set if it is available. 361 void EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset, 362 unsigned Size) const; 363 364 /// EmitLabelReference - Emit something like ".long Label" 365 /// where the size in bytes of the directive is specified by Size and Label 366 /// specifies the label. 367 void EmitLabelReference(const MCSymbol *Label, unsigned Size) const { 368 EmitLabelPlusOffset(Label, 0, Size); 369 } 370 371 //===------------------------------------------------------------------===// 372 // Dwarf Emission Helper Routines 373 //===------------------------------------------------------------------===// 374 375 /// EmitSLEB128 - emit the specified signed leb128 value. 376 void EmitSLEB128(int64_t Value, const char *Desc = 0) const; 377 378 /// EmitULEB128 - emit the specified unsigned leb128 value. 379 void EmitULEB128(uint64_t Value, const char *Desc = 0, 380 unsigned PadTo = 0) const; 381 382 /// EmitCFAByte - Emit a .byte 42 directive for a DW_CFA_xxx value. 383 void EmitCFAByte(unsigned Val) const; 384 385 /// EmitEncodingByte - Emit a .byte 42 directive that corresponds to an 386 /// encoding. If verbose assembly output is enabled, we output comments 387 /// describing the encoding. Desc is a string saying what the encoding is 388 /// specifying (e.g. "LSDA"). 389 void EmitEncodingByte(unsigned Val, const char *Desc = 0) const; 390 391 /// GetSizeOfEncodedValue - Return the size of the encoding in bytes. 392 unsigned GetSizeOfEncodedValue(unsigned Encoding) const; 393 394 /// EmitReference - Emit reference to a ttype global with a specified encoding. 395 void EmitTTypeReference(const GlobalValue *GV, unsigned Encoding) const; 396 397 /// EmitSectionOffset - Emit the 4-byte offset of Label from the start of 398 /// its section. This can be done with a special directive if the target 399 /// supports it (e.g. cygwin) or by emitting it as an offset from a label at 400 /// the start of the section. 401 /// 402 /// SectionLabel is a temporary label emitted at the start of the section 403 /// that Label lives in. 404 void EmitSectionOffset(const MCSymbol *Label, 405 const MCSymbol *SectionLabel) const; 406 407 /// getISAEncoding - Get the value for DW_AT_APPLE_isa. Zero if no isa 408 /// encoding specified. 409 virtual unsigned getISAEncoding() { return 0; } 410 411 /// EmitDwarfRegOp - Emit dwarf register operation. 412 virtual void EmitDwarfRegOp(const MachineLocation &MLoc, 413 bool Indirect) const; 414 415 //===------------------------------------------------------------------===// 416 // Dwarf Lowering Routines 417 //===------------------------------------------------------------------===// 418 419 /// \brief Emit frame instruction to describe the layout of the frame. 420 void emitCFIInstruction(const MCCFIInstruction &Inst) const; 421 422 //===------------------------------------------------------------------===// 423 // Inline Asm Support 424 //===------------------------------------------------------------------===// 425 public: 426 // These are hooks that targets can override to implement inline asm 427 // support. These should probably be moved out of AsmPrinter someday. 428 429 /// PrintSpecial - Print information related to the specified machine instr 430 /// that is independent of the operand, and may be independent of the instr 431 /// itself. This can be useful for portably encoding the comment character 432 /// or other bits of target-specific knowledge into the asmstrings. The 433 /// syntax used is ${:comment}. Targets can override this to add support 434 /// for their own strange codes. 435 virtual void PrintSpecial(const MachineInstr *MI, raw_ostream &OS, 436 const char *Code) const; 437 438 /// PrintAsmOperand - Print the specified operand of MI, an INLINEASM 439 /// instruction, using the specified assembler variant. Targets should 440 /// override this to format as appropriate. This method can return true if 441 /// the operand is erroneous. 442 virtual bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo, 443 unsigned AsmVariant, const char *ExtraCode, 444 raw_ostream &OS); 445 446 /// PrintAsmMemoryOperand - Print the specified operand of MI, an INLINEASM 447 /// instruction, using the specified assembler variant as an address. 448 /// Targets should override this to format as appropriate. This method can 449 /// return true if the operand is erroneous. 450 virtual bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo, 451 unsigned AsmVariant, 452 const char *ExtraCode, 453 raw_ostream &OS); 454 455 private: 456 /// Private state for PrintSpecial() 457 // Assign a unique ID to this machine instruction. 458 mutable const MachineInstr *LastMI; 459 mutable unsigned LastFn; 460 mutable unsigned Counter; 461 mutable unsigned SetCounter; 462 463 /// EmitInlineAsm - Emit a blob of inline asm to the output streamer. 464 void EmitInlineAsm(StringRef Str, const MDNode *LocMDNode = 0, 465 InlineAsm::AsmDialect AsmDialect = InlineAsm::AD_ATT) const; 466 467 /// EmitInlineAsm - This method formats and emits the specified machine 468 /// instruction that is an inline asm. 469 void EmitInlineAsm(const MachineInstr *MI) const; 470 471 //===------------------------------------------------------------------===// 472 // Internal Implementation Details 473 //===------------------------------------------------------------------===// 474 475 /// EmitVisibility - This emits visibility information about symbol, if 476 /// this is suported by the target. 477 void EmitVisibility(MCSymbol *Sym, unsigned Visibility, 478 bool IsDefinition = true) const; 479 480 void EmitLinkage(unsigned Linkage, MCSymbol *GVSym) const; 481 482 void EmitJumpTableEntry(const MachineJumpTableInfo *MJTI, 483 const MachineBasicBlock *MBB, 484 unsigned uid) const; 485 void EmitLLVMUsedList(const ConstantArray *InitList); 486 void EmitXXStructorList(const Constant *List, bool isCtor); 487 GCMetadataPrinter *GetOrCreateGCPrinter(GCStrategy *C); 488 }; 489 } 490 491 #endif 492
