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