MCStreamer.h revision 0dd2c9331887b9d0aa06b1e201c5eda4361365fc
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 /// EmitLabel - Emit a label for @p Symbol into the current section. 114 /// 115 /// This corresponds to an assembler statement such as: 116 /// foo: 117 /// 118 /// @param Symbol - The symbol to emit. A given symbol should only be 119 /// emitted as a label once, and symbols emitted as a label should never be 120 /// used in an assignment. 121 virtual void EmitLabel(MCSymbol *Symbol) = 0; 122 123 /// EmitAssemblerFlag - Note in the output the specified @p Flag 124 virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) = 0; 125 126 /// EmitAssignment - Emit an assignment of @p Value to @p Symbol. 127 /// 128 /// This corresponds to an assembler statement such as: 129 /// symbol = value 130 /// 131 /// The assignment generates no code, but has the side effect of binding the 132 /// value in the current context. For the assembly streamer, this prints the 133 /// binding into the .s file. 134 /// 135 /// @param Symbol - The symbol being assigned to. 136 /// @param Value - The value for the symbol. 137 virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) = 0; 138 139 /// EmitSymbolAttribute - Add the given @p Attribute to @p Symbol. 140 virtual void EmitSymbolAttribute(MCSymbol *Symbol, 141 MCSymbolAttr Attribute) = 0; 142 143 /// EmitSymbolDesc - Set the @p DescValue for the @p Symbol. 144 /// 145 /// @param Symbol - The symbol to have its n_desc field set. 146 /// @param DescValue - The value to set into the n_desc field. 147 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) = 0; 148 149 /// BeginCOFFSymbolDef - Start emitting COFF symbol definition 150 /// 151 /// @param Symbol - The symbol to have its External & Type fields set. 152 virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) = 0; 153 154 /// EmitCOFFSymbolStorageClass - Emit the storage class of the symbol. 155 /// 156 /// @param StorageClass - The storage class the symbol should have. 157 virtual void EmitCOFFSymbolStorageClass(int StorageClass) = 0; 158 159 /// EmitCOFFSymbolType - Emit the type of the symbol. 160 /// 161 /// @param Type - A COFF type identifier (see COFF::SymbolType in X86COFF.h) 162 virtual void EmitCOFFSymbolType(int Type) = 0; 163 164 /// EndCOFFSymbolDef - Marks the end of the symbol definition. 165 virtual void EndCOFFSymbolDef() = 0; 166 167 /// EmitELFSize - Emit an ELF .size directive. 168 /// 169 /// This corresponds to an assembler statement such as: 170 /// .size symbol, expression 171 /// 172 virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) = 0; 173 174 /// EmitCommonSymbol - Emit a common symbol. 175 /// 176 /// @param Symbol - The common symbol to emit. 177 /// @param Size - The size of the common symbol. 178 /// @param ByteAlignment - The alignment of the symbol if 179 /// non-zero. This must be a power of 2. 180 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size, 181 unsigned ByteAlignment) = 0; 182 183 /// EmitLocalCommonSymbol - Emit a local common (.lcomm) symbol. 184 /// 185 /// @param Symbol - The common symbol to emit. 186 /// @param Size - The size of the common symbol. 187 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) = 0; 188 189 /// EmitZerofill - Emit the zerofill section and an optional symbol. 190 /// 191 /// @param Section - The zerofill section to create and or to put the symbol 192 /// @param Symbol - The zerofill symbol to emit, if non-NULL. 193 /// @param Size - The size of the zerofill symbol. 194 /// @param ByteAlignment - The alignment of the zerofill symbol if 195 /// non-zero. This must be a power of 2 on some targets. 196 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0, 197 unsigned Size = 0,unsigned ByteAlignment = 0) = 0; 198 199 /// EmitTBSSSymbol - Emit a thread local bss (.tbss) symbol. 200 /// 201 /// @param Section - The thread local common section. 202 /// @param Symbol - The thread local common symbol to emit. 203 /// @param Size - The size of the symbol. 204 /// @param ByteAlignment - The alignment of the thread local common symbol 205 /// if non-zero. This must be a power of 2 on some targets. 206 virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol, 207 uint64_t Size, unsigned ByteAlignment = 0) = 0; 208 /// @} 209 /// @name Generating Data 210 /// @{ 211 212 /// EmitBytes - Emit the bytes in \arg Data into the output. 213 /// 214 /// This is used to implement assembler directives such as .byte, .ascii, 215 /// etc. 216 virtual void EmitBytes(StringRef Data, unsigned AddrSpace) = 0; 217 218 /// EmitValue - Emit the expression @p Value into the output as a native 219 /// integer of the given @p Size bytes. 220 /// 221 /// This is used to implement assembler directives such as .word, .quad, 222 /// etc. 223 /// 224 /// @param Value - The value to emit. 225 /// @param Size - The size of the integer (in bytes) to emit. This must 226 /// match a native machine width. 227 virtual void EmitValue(const MCExpr *Value, unsigned Size, 228 unsigned AddrSpace = 0) = 0; 229 230 /// EmitIntValue - Special case of EmitValue that avoids the client having 231 /// to pass in a MCExpr for constant integers. 232 virtual void EmitIntValue(uint64_t Value, unsigned Size, 233 unsigned AddrSpace = 0); 234 235 /// EmitSymbolValue - Special case of EmitValue that avoids the client 236 /// having to pass in a MCExpr for MCSymbols. 237 virtual void EmitSymbolValue(const MCSymbol *Sym, unsigned Size, 238 unsigned AddrSpace); 239 240 /// EmitGPRel32Value - Emit the expression @p Value into the output as a 241 /// gprel32 (32-bit GP relative) value. 242 /// 243 /// This is used to implement assembler directives such as .gprel32 on 244 /// targets that support them. 245 virtual void EmitGPRel32Value(const MCExpr *Value) = 0; 246 247 /// EmitFill - Emit NumBytes bytes worth of the value specified by 248 /// FillValue. This implements directives such as '.space'. 249 virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue, 250 unsigned AddrSpace); 251 252 /// EmitZeros - Emit NumBytes worth of zeros. This is a convenience 253 /// function that just wraps EmitFill. 254 void EmitZeros(uint64_t NumBytes, unsigned AddrSpace) { 255 EmitFill(NumBytes, 0, AddrSpace); 256 } 257 258 259 /// EmitValueToAlignment - Emit some number of copies of @p Value until 260 /// the byte alignment @p ByteAlignment is reached. 261 /// 262 /// If the number of bytes need to emit for the alignment is not a multiple 263 /// of @p ValueSize, then the contents of the emitted fill bytes is 264 /// undefined. 265 /// 266 /// This used to implement the .align assembler directive. 267 /// 268 /// @param ByteAlignment - The alignment to reach. This must be a power of 269 /// two on some targets. 270 /// @param Value - The value to use when filling bytes. 271 /// @param ValueSize - The size of the integer (in bytes) to emit for 272 /// @p Value. This must match a native machine width. 273 /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If 274 /// the alignment cannot be reached in this many bytes, no bytes are 275 /// emitted. 276 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0, 277 unsigned ValueSize = 1, 278 unsigned MaxBytesToEmit = 0) = 0; 279 280 /// EmitCodeAlignment - Emit nops until the byte alignment @p ByteAlignment 281 /// is reached. 282 /// 283 /// This used to align code where the alignment bytes may be executed. This 284 /// can emit different bytes for different sizes to optimize execution. 285 /// 286 /// @param ByteAlignment - The alignment to reach. This must be a power of 287 /// two on some targets. 288 /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If 289 /// the alignment cannot be reached in this many bytes, no bytes are 290 /// emitted. 291 virtual void EmitCodeAlignment(unsigned ByteAlignment, 292 unsigned MaxBytesToEmit = 0) = 0; 293 294 /// EmitValueToOffset - Emit some number of copies of @p Value until the 295 /// byte offset @p Offset is reached. 296 /// 297 /// This is used to implement assembler directives such as .org. 298 /// 299 /// @param Offset - The offset to reach. This may be an expression, but the 300 /// expression must be associated with the current section. 301 /// @param Value - The value to use when filling bytes. 302 virtual void EmitValueToOffset(const MCExpr *Offset, 303 unsigned char Value = 0) = 0; 304 305 /// @} 306 307 /// EmitFileDirective - Switch to a new logical file. This is used to 308 /// implement the '.file "foo.c"' assembler directive. 309 virtual void EmitFileDirective(StringRef Filename) = 0; 310 311 /// EmitDwarfFileDirective - Associate a filename with a specified logical 312 /// file number. This implements the DWARF2 '.file 4 "foo.c"' assembler 313 /// directive. 314 virtual void EmitDwarfFileDirective(unsigned FileNo,StringRef Filename) = 0; 315 316 /// EmitInstruction - Emit the given @p Instruction into the current 317 /// section. 318 virtual void EmitInstruction(const MCInst &Inst) = 0; 319 320 /// EmitRawText - If this file is backed by a assembly streamer, this dumps 321 /// the specified string in the output .s file. This capability is 322 /// indicated by the hasRawTextSupport() predicate. By default this aborts. 323 virtual void EmitRawText(StringRef String); 324 void EmitRawText(const Twine &String); 325 326 /// Finish - Finish emission of machine code. 327 virtual void Finish() = 0; 328 }; 329 330 /// createNullStreamer - Create a dummy machine code streamer, which does 331 /// nothing. This is useful for timing the assembler front end. 332 MCStreamer *createNullStreamer(MCContext &Ctx); 333 334 /// createAsmStreamer - Create a machine code streamer which will print out 335 /// assembly for the native target, suitable for compiling with a native 336 /// assembler. 337 /// 338 /// \param InstPrint - If given, the instruction printer to use. If not given 339 /// the MCInst representation will be printed. This method takes ownership of 340 /// InstPrint. 341 /// 342 /// \param CE - If given, a code emitter to use to show the instruction 343 /// encoding inline with the assembly. This method takes ownership of \arg CE. 344 /// 345 /// \param ShowInst - Whether to show the MCInst representation inline with 346 /// the assembly. 347 MCStreamer *createAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS, 348 bool isLittleEndian, bool isVerboseAsm, 349 MCInstPrinter *InstPrint = 0, 350 MCCodeEmitter *CE = 0, 351 bool ShowInst = false); 352 353 /// createMachOStreamer - Create a machine code streamer which will generate 354 /// Mach-O format object files. 355 /// 356 /// Takes ownership of \arg TAB and \arg CE. 357 MCStreamer *createMachOStreamer(MCContext &Ctx, TargetAsmBackend &TAB, 358 raw_ostream &OS, MCCodeEmitter *CE, 359 bool RelaxAll = false); 360 361 /// createWinCOFFStreamer - Create a machine code streamer which will 362 /// generate Microsoft COFF format object files. 363 /// 364 /// Takes ownership of \arg TAB and \arg CE. 365 MCStreamer *createWinCOFFStreamer(MCContext &Ctx, 366 TargetAsmBackend &TAB, 367 MCCodeEmitter &CE, raw_ostream &OS, 368 bool RelaxAll = false); 369 370 /// createELFStreamer - Create a machine code streamer which will generate 371 /// ELF format object files. 372 MCStreamer *createELFStreamer(MCContext &Ctx, TargetAsmBackend &TAB, 373 raw_ostream &OS, MCCodeEmitter *CE, 374 bool RelaxAll = false); 375 376 /// createLoggingStreamer - Create a machine code streamer which just logs the 377 /// API calls and then dispatches to another streamer. 378 /// 379 /// The new streamer takes ownership of the \arg Child. 380 MCStreamer *createLoggingStreamer(MCStreamer *Child, raw_ostream &OS); 381 382} // end namespace llvm 383 384#endif 385