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