MCStreamer.h revision 3bb435301a2b5c901a993b0e151d05b596697038
1//===- MCStreamer.h - High-level Streaming Machine Code Output --*- 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 declares the MCStreamer class. 11// 12//===----------------------------------------------------------------------===// 13 14#ifndef LLVM_MC_MCSTREAMER_H 15#define LLVM_MC_MCSTREAMER_H 16 17#include "llvm/System/DataTypes.h" 18#include "llvm/MC/MCDirectives.h" 19 20namespace llvm { 21 class MCAsmInfo; 22 class MCCodeEmitter; 23 class MCContext; 24 class MCExpr; 25 class MCInst; 26 class MCInstPrinter; 27 class MCSection; 28 class MCSymbol; 29 class StringRef; 30 class TargetAsmBackend; 31 class Twine; 32 class raw_ostream; 33 class formatted_raw_ostream; 34 35 /// MCStreamer - Streaming machine code generation interface. This interface 36 /// is intended to provide a programatic interface that is very similar to the 37 /// level that an assembler .s file provides. It has callbacks to emit bytes, 38 /// handle directives, etc. The implementation of this interface retains 39 /// state to know what the current section is etc. 40 /// 41 /// There are multiple implementations of this interface: one for writing out 42 /// a .s file, and implementations that write out .o files of various formats. 43 /// 44 class MCStreamer { 45 MCContext &Context; 46 47 MCStreamer(const MCStreamer&); // DO NOT IMPLEMENT 48 MCStreamer &operator=(const MCStreamer&); // DO NOT IMPLEMENT 49 50 protected: 51 MCStreamer(MCContext &Ctx); 52 53 /// CurSection - This is the current section code is being emitted to, it is 54 /// kept up to date by SwitchSection. 55 const MCSection *CurSection; 56 57 /// PrevSection - This is the previous section code is being emitted to, it 58 /// is kept up to date by SwitchSection. 59 const MCSection *PrevSection; 60 61 public: 62 virtual ~MCStreamer(); 63 64 MCContext &getContext() const { return Context; } 65 66 /// @name Assembly File Formatting. 67 /// @{ 68 69 /// isVerboseAsm - Return true if this streamer supports verbose assembly 70 /// and if it is enabled. 71 virtual bool isVerboseAsm() const { return false; } 72 73 /// hasRawTextSupport - Return true if this asm streamer supports emitting 74 /// unformatted text to the .s file with EmitRawText. 75 virtual bool hasRawTextSupport() const { return false; } 76 77 /// AddComment - Add a comment that can be emitted to the generated .s 78 /// file if applicable as a QoI issue to make the output of the compiler 79 /// more readable. This only affects the MCAsmStreamer, and only when 80 /// verbose assembly output is enabled. 81 /// 82 /// If the comment includes embedded \n's, they will each get the comment 83 /// prefix as appropriate. The added comment should not end with a \n. 84 virtual void AddComment(const Twine &T) {} 85 86 /// GetCommentOS - Return a raw_ostream that comments can be written to. 87 /// Unlike AddComment, you are required to terminate comments with \n if you 88 /// use this method. 89 virtual raw_ostream &GetCommentOS(); 90 91 /// AddBlankLine - Emit a blank line to a .s file to pretty it up. 92 virtual void AddBlankLine() {} 93 94 /// @} 95 96 /// @name Symbol & Section Management 97 /// @{ 98 99 /// getCurrentSection - Return the current section that the streamer is 100 /// emitting code to. 101 const MCSection *getCurrentSection() const { return CurSection; } 102 103 /// getPreviousSection - Return the previous section that the streamer is 104 /// emitting code to. 105 const MCSection *getPreviousSection() const { return PrevSection; } 106 107 /// SwitchSection - Set the current section where code is being emitted to 108 /// @p Section. This is required to update CurSection. 109 /// 110 /// This corresponds to assembler directives like .section, .text, etc. 111 virtual void SwitchSection(const MCSection *Section) = 0; 112 113 /// InitSections - Create the default sections and set the initial one. 114 virtual void InitSections() = 0; 115 116 /// EmitLabel - Emit a label for @p Symbol into the current section. 117 /// 118 /// This corresponds to an assembler statement such as: 119 /// foo: 120 /// 121 /// @param Symbol - The symbol to emit. A given symbol should only be 122 /// emitted as a label once, and symbols emitted as a label should never be 123 /// used in an assignment. 124 virtual void EmitLabel(MCSymbol *Symbol) = 0; 125 126 /// EmitAssemblerFlag - Note in the output the specified @p Flag 127 virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) = 0; 128 129 /// EmitAssignment - Emit an assignment of @p Value to @p Symbol. 130 /// 131 /// This corresponds to an assembler statement such as: 132 /// symbol = value 133 /// 134 /// The assignment generates no code, but has the side effect of binding the 135 /// value in the current context. For the assembly streamer, this prints the 136 /// binding into the .s file. 137 /// 138 /// @param Symbol - The symbol being assigned to. 139 /// @param Value - The value for the symbol. 140 virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) = 0; 141 142 /// EmitSymbolAttribute - Add the given @p Attribute to @p Symbol. 143 virtual void EmitSymbolAttribute(MCSymbol *Symbol, 144 MCSymbolAttr Attribute) = 0; 145 146 /// EmitSymbolDesc - Set the @p DescValue for the @p Symbol. 147 /// 148 /// @param Symbol - The symbol to have its n_desc field set. 149 /// @param DescValue - The value to set into the n_desc field. 150 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) = 0; 151 152 /// BeginCOFFSymbolDef - Start emitting COFF symbol definition 153 /// 154 /// @param Symbol - The symbol to have its External & Type fields set. 155 virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) = 0; 156 157 /// EmitCOFFSymbolStorageClass - Emit the storage class of the symbol. 158 /// 159 /// @param StorageClass - The storage class the symbol should have. 160 virtual void EmitCOFFSymbolStorageClass(int StorageClass) = 0; 161 162 /// EmitCOFFSymbolType - Emit the type of the symbol. 163 /// 164 /// @param Type - A COFF type identifier (see COFF::SymbolType in X86COFF.h) 165 virtual void EmitCOFFSymbolType(int Type) = 0; 166 167 /// EndCOFFSymbolDef - Marks the end of the symbol definition. 168 virtual void EndCOFFSymbolDef() = 0; 169 170 /// EmitELFSize - Emit an ELF .size directive. 171 /// 172 /// This corresponds to an assembler statement such as: 173 /// .size symbol, expression 174 /// 175 virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) = 0; 176 177 /// EmitCommonSymbol - Emit a common symbol. 178 /// 179 /// @param Symbol - The common symbol to emit. 180 /// @param Size - The size of the common symbol. 181 /// @param ByteAlignment - The alignment of the symbol if 182 /// non-zero. This must be a power of 2. 183 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size, 184 unsigned ByteAlignment) = 0; 185 186 /// EmitLocalCommonSymbol - Emit a local common (.lcomm) symbol. 187 /// 188 /// @param Symbol - The common symbol to emit. 189 /// @param Size - The size of the common symbol. 190 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) = 0; 191 192 /// EmitZerofill - Emit the zerofill section and an optional symbol. 193 /// 194 /// @param Section - The zerofill section to create and or to put the symbol 195 /// @param Symbol - The zerofill symbol to emit, if non-NULL. 196 /// @param Size - The size of the zerofill symbol. 197 /// @param ByteAlignment - The alignment of the zerofill symbol if 198 /// non-zero. This must be a power of 2 on some targets. 199 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0, 200 unsigned Size = 0,unsigned ByteAlignment = 0) = 0; 201 202 /// EmitTBSSSymbol - Emit a thread local bss (.tbss) symbol. 203 /// 204 /// @param Section - The thread local common section. 205 /// @param Symbol - The thread local common symbol to emit. 206 /// @param Size - The size of the symbol. 207 /// @param ByteAlignment - The alignment of the thread local common symbol 208 /// if non-zero. This must be a power of 2 on some targets. 209 virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol, 210 uint64_t Size, unsigned ByteAlignment = 0) = 0; 211 /// @} 212 /// @name Generating Data 213 /// @{ 214 215 /// EmitBytes - Emit the bytes in \arg Data into the output. 216 /// 217 /// This is used to implement assembler directives such as .byte, .ascii, 218 /// etc. 219 virtual void EmitBytes(StringRef Data, unsigned AddrSpace) = 0; 220 221 /// EmitValue - Emit the expression @p Value into the output as a native 222 /// integer of the given @p Size bytes. 223 /// 224 /// This is used to implement assembler directives such as .word, .quad, 225 /// etc. 226 /// 227 /// @param Value - The value to emit. 228 /// @param Size - The size of the integer (in bytes) to emit. This must 229 /// match a native machine width. 230 virtual void EmitValue(const MCExpr *Value, unsigned Size, 231 unsigned AddrSpace = 0) = 0; 232 233 /// EmitIntValue - Special case of EmitValue that avoids the client having 234 /// to pass in a MCExpr for constant integers. 235 virtual void EmitIntValue(uint64_t Value, unsigned Size, 236 unsigned AddrSpace = 0); 237 238 /// EmitULEB128Value - Special case of EmitValue that takes an ULEB128 and 239 /// emits the needed bytes for the encoded value. 240 virtual void EmitULEB128Value(uint64_t Value, unsigned AddrSpace = 0); 241 242 /// EmitSLEB128Value - Special case of EmitValue that takes an SLEB128 and 243 /// emits the needed bytes for the encoded value. 244 virtual void EmitSLEB128Value(int64_t Value, unsigned AddrSpace = 0); 245 246 /// EmitSymbolValue - Special case of EmitValue that avoids the client 247 /// having to pass in a MCExpr for MCSymbols. 248 virtual void EmitSymbolValue(const MCSymbol *Sym, unsigned Size, 249 unsigned AddrSpace = 0); 250 251 /// EmitGPRel32Value - Emit the expression @p Value into the output as a 252 /// gprel32 (32-bit GP relative) value. 253 /// 254 /// This is used to implement assembler directives such as .gprel32 on 255 /// targets that support them. 256 virtual void EmitGPRel32Value(const MCExpr *Value) = 0; 257 258 /// EmitFill - Emit NumBytes bytes worth of the value specified by 259 /// FillValue. This implements directives such as '.space'. 260 virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue, 261 unsigned AddrSpace); 262 263 /// EmitZeros - Emit NumBytes worth of zeros. This is a convenience 264 /// function that just wraps EmitFill. 265 void EmitZeros(uint64_t NumBytes, unsigned AddrSpace) { 266 EmitFill(NumBytes, 0, AddrSpace); 267 } 268 269 270 /// EmitValueToAlignment - Emit some number of copies of @p Value until 271 /// the byte alignment @p ByteAlignment is reached. 272 /// 273 /// If the number of bytes need to emit for the alignment is not a multiple 274 /// of @p ValueSize, then the contents of the emitted fill bytes is 275 /// undefined. 276 /// 277 /// This used to implement the .align assembler directive. 278 /// 279 /// @param ByteAlignment - The alignment to reach. This must be a power of 280 /// two on some targets. 281 /// @param Value - The value to use when filling bytes. 282 /// @param ValueSize - The size of the integer (in bytes) to emit for 283 /// @p Value. This must match a native machine width. 284 /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If 285 /// the alignment cannot be reached in this many bytes, no bytes are 286 /// emitted. 287 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0, 288 unsigned ValueSize = 1, 289 unsigned MaxBytesToEmit = 0) = 0; 290 291 /// EmitCodeAlignment - Emit nops until the byte alignment @p ByteAlignment 292 /// is reached. 293 /// 294 /// This used to align code where the alignment bytes may be executed. This 295 /// can emit different bytes for different sizes to optimize execution. 296 /// 297 /// @param ByteAlignment - The alignment to reach. This must be a power of 298 /// two on some targets. 299 /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If 300 /// the alignment cannot be reached in this many bytes, no bytes are 301 /// emitted. 302 virtual void EmitCodeAlignment(unsigned ByteAlignment, 303 unsigned MaxBytesToEmit = 0) = 0; 304 305 /// EmitValueToOffset - Emit some number of copies of @p Value until the 306 /// byte offset @p Offset is reached. 307 /// 308 /// This is used to implement assembler directives such as .org. 309 /// 310 /// @param Offset - The offset to reach. This may be an expression, but the 311 /// expression must be associated with the current section. 312 /// @param Value - The value to use when filling bytes. 313 virtual void EmitValueToOffset(const MCExpr *Offset, 314 unsigned char Value = 0) = 0; 315 316 /// @} 317 318 /// EmitFileDirective - Switch to a new logical file. This is used to 319 /// implement the '.file "foo.c"' assembler directive. 320 virtual void EmitFileDirective(StringRef Filename) = 0; 321 322 /// EmitDwarfFileDirective - Associate a filename with a specified logical 323 /// file number. This implements the DWARF2 '.file 4 "foo.c"' assembler 324 /// directive. 325 virtual void EmitDwarfFileDirective(unsigned FileNo,StringRef Filename) = 0; 326 327 /// EmitInstruction - Emit the given @p Instruction into the current 328 /// section. 329 virtual void EmitInstruction(const MCInst &Inst) = 0; 330 331 /// EmitRawText - If this file is backed by a assembly streamer, this dumps 332 /// the specified string in the output .s file. This capability is 333 /// indicated by the hasRawTextSupport() predicate. By default this aborts. 334 virtual void EmitRawText(StringRef String); 335 void EmitRawText(const Twine &String); 336 337 /// Finish - Finish emission of machine code. 338 virtual void Finish() = 0; 339 }; 340 341 /// createNullStreamer - Create a dummy machine code streamer, which does 342 /// nothing. This is useful for timing the assembler front end. 343 MCStreamer *createNullStreamer(MCContext &Ctx); 344 345 /// createAsmStreamer - Create a machine code streamer which will print out 346 /// assembly for the native target, suitable for compiling with a native 347 /// assembler. 348 /// 349 /// \param InstPrint - If given, the instruction printer to use. If not given 350 /// the MCInst representation will be printed. This method takes ownership of 351 /// InstPrint. 352 /// 353 /// \param CE - If given, a code emitter to use to show the instruction 354 /// encoding inline with the assembly. This method takes ownership of \arg CE. 355 /// 356 /// \param ShowInst - Whether to show the MCInst representation inline with 357 /// the assembly. 358 MCStreamer *createAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS, 359 bool isLittleEndian, bool isVerboseAsm, 360 MCInstPrinter *InstPrint = 0, 361 MCCodeEmitter *CE = 0, 362 bool ShowInst = false); 363 364 /// createMachOStreamer - Create a machine code streamer which will generate 365 /// Mach-O format object files. 366 /// 367 /// Takes ownership of \arg TAB and \arg CE. 368 MCStreamer *createMachOStreamer(MCContext &Ctx, TargetAsmBackend &TAB, 369 raw_ostream &OS, MCCodeEmitter *CE, 370 bool RelaxAll = false); 371 372 /// createWinCOFFStreamer - Create a machine code streamer which will 373 /// generate Microsoft COFF format object files. 374 /// 375 /// Takes ownership of \arg TAB and \arg CE. 376 MCStreamer *createWinCOFFStreamer(MCContext &Ctx, 377 TargetAsmBackend &TAB, 378 MCCodeEmitter &CE, raw_ostream &OS, 379 bool RelaxAll = false); 380 381 /// createELFStreamer - Create a machine code streamer which will generate 382 /// ELF format object files. 383 MCStreamer *createELFStreamer(MCContext &Ctx, TargetAsmBackend &TAB, 384 raw_ostream &OS, MCCodeEmitter *CE, 385 bool RelaxAll = false); 386 387 /// createLoggingStreamer - Create a machine code streamer which just logs the 388 /// API calls and then dispatches to another streamer. 389 /// 390 /// The new streamer takes ownership of the \arg Child. 391 MCStreamer *createLoggingStreamer(MCStreamer *Child, raw_ostream &OS); 392 393} // end namespace llvm 394 395#endif 396