MCStreamer.h revision 91bead790518fcf5cb26019fb1ebf2372e8a5b3f
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; 30class 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 public: 58 virtual ~MCStreamer(); 59 60 MCContext &getContext() const { return Context; } 61 62 /// @name Assembly File Formatting. 63 /// @{ 64 65 /// isVerboseAsm - Return true if this streamer supports verbose assembly 66 /// and if it is enabled. 67 virtual bool isVerboseAsm() const { return false; } 68 69 /// hasRawTextSupport - Return true if this asm streamer supports emitting 70 /// unformatted text to the .s file with EmitRawText. 71 virtual bool hasRawTextSupport() const { return false; } 72 73 /// AddComment - Add a comment that can be emitted to the generated .s 74 /// file if applicable as a QoI issue to make the output of the compiler 75 /// more readable. This only affects the MCAsmStreamer, and only when 76 /// verbose assembly output is enabled. 77 /// 78 /// If the comment includes embedded \n's, they will each get the comment 79 /// prefix as appropriate. The added comment should not end with a \n. 80 virtual void AddComment(const Twine &T) {} 81 82 /// GetCommentOS - Return a raw_ostream that comments can be written to. 83 /// Unlike AddComment, you are required to terminate comments with \n if you 84 /// use this method. 85 virtual raw_ostream &GetCommentOS(); 86 87 /// AddBlankLine - Emit a blank line to a .s file to pretty it up. 88 virtual void AddBlankLine() {} 89 90 /// @} 91 92 /// @name Symbol & Section Management 93 /// @{ 94 95 /// getCurrentSection - Return the current section that the streamer is 96 /// emitting code to. 97 const MCSection *getCurrentSection() const { return CurSection; } 98 99 /// SwitchSection - Set the current section where code is being emitted to 100 /// @p Section. This is required to update CurSection. 101 /// 102 /// This corresponds to assembler directives like .section, .text, etc. 103 virtual void SwitchSection(const MCSection *Section) = 0; 104 105 /// EmitLabel - Emit a label for @p Symbol into the current section. 106 /// 107 /// This corresponds to an assembler statement such as: 108 /// foo: 109 /// 110 /// @param Symbol - The symbol to emit. A given symbol should only be 111 /// emitted as a label once, and symbols emitted as a label should never be 112 /// used in an assignment. 113 virtual void EmitLabel(MCSymbol *Symbol) = 0; 114 115 /// EmitAssemblerFlag - Note in the output the specified @p Flag 116 virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) = 0; 117 118 /// EmitAssignment - Emit an assignment of @p Value to @p Symbol. 119 /// 120 /// This corresponds to an assembler statement such as: 121 /// symbol = value 122 /// 123 /// The assignment generates no code, but has the side effect of binding the 124 /// value in the current context. For the assembly streamer, this prints the 125 /// binding into the .s file. 126 /// 127 /// @param Symbol - The symbol being assigned to. 128 /// @param Value - The value for the symbol. 129 virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) = 0; 130 131 /// EmitSymbolAttribute - Add the given @p Attribute to @p Symbol. 132 virtual void EmitSymbolAttribute(MCSymbol *Symbol, 133 MCSymbolAttr Attribute) = 0; 134 135 /// EmitSymbolDesc - Set the @p DescValue for the @p Symbol. 136 /// 137 /// @param Symbol - The symbol to have its n_desc field set. 138 /// @param DescValue - The value to set into the n_desc field. 139 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) = 0; 140 141 142 /// EmitELFSize - Emit an ELF .size directive. 143 /// 144 /// This corresponds to an assembler statement such as: 145 /// .size symbol, expression 146 /// 147 virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) = 0; 148 149 /// EmitCommonSymbol - Emit a common symbol. 150 /// 151 /// @param Symbol - The common symbol to emit. 152 /// @param Size - The size of the common symbol. 153 /// @param ByteAlignment - The alignment of the symbol if 154 /// non-zero. This must be a power of 2. 155 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size, 156 unsigned ByteAlignment) = 0; 157 158 /// EmitLocalCommonSymbol - Emit a local common (.lcomm) symbol. 159 /// 160 /// @param Symbol - The common symbol to emit. 161 /// @param Size - The size of the common symbol. 162 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) = 0; 163 164 /// EmitZerofill - Emit a the zerofill section and an option symbol. 165 /// 166 /// @param Section - The zerofill section to create and or to put the symbol 167 /// @param Symbol - The zerofill symbol to emit, if non-NULL. 168 /// @param Size - The size of the zerofill symbol. 169 /// @param ByteAlignment - The alignment of the zerofill symbol if 170 /// non-zero. This must be a power of 2 on some targets. 171 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0, 172 unsigned Size = 0,unsigned ByteAlignment = 0) = 0; 173 174 /// @} 175 /// @name Generating Data 176 /// @{ 177 178 /// EmitBytes - Emit the bytes in \arg Data into the output. 179 /// 180 /// This is used to implement assembler directives such as .byte, .ascii, 181 /// etc. 182 virtual void EmitBytes(StringRef Data, unsigned AddrSpace) = 0; 183 184 /// EmitValue - Emit the expression @p Value into the output as a native 185 /// integer of the given @p Size bytes. 186 /// 187 /// This is used to implement assembler directives such as .word, .quad, 188 /// etc. 189 /// 190 /// @param Value - The value to emit. 191 /// @param Size - The size of the integer (in bytes) to emit. This must 192 /// match a native machine width. 193 virtual void EmitValue(const MCExpr *Value, unsigned Size, 194 unsigned AddrSpace) = 0; 195 196 /// EmitIntValue - Special case of EmitValue that avoids the client having 197 /// to pass in a MCExpr for constant integers. 198 virtual void EmitIntValue(uint64_t Value, unsigned Size,unsigned AddrSpace); 199 200 /// EmitSymbolValue - Special case of EmitValue that avoids the client 201 /// having to pass in a MCExpr for MCSymbols. 202 virtual void EmitSymbolValue(const MCSymbol *Sym, unsigned Size, 203 unsigned AddrSpace); 204 205 /// EmitGPRel32Value - Emit the expression @p Value into the output as a 206 /// gprel32 (32-bit GP relative) value. 207 /// 208 /// This is used to implement assembler directives such as .gprel32 on 209 /// targets that support them. 210 virtual void EmitGPRel32Value(const MCExpr *Value) = 0; 211 212 /// EmitFill - Emit NumBytes bytes worth of the value specified by 213 /// FillValue. This implements directives such as '.space'. 214 virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue, 215 unsigned AddrSpace); 216 217 /// EmitZeros - Emit NumBytes worth of zeros. This is a convenience 218 /// function that just wraps EmitFill. 219 void EmitZeros(uint64_t NumBytes, unsigned AddrSpace) { 220 EmitFill(NumBytes, 0, AddrSpace); 221 } 222 223 224 /// EmitValueToAlignment - Emit some number of copies of @p Value until 225 /// the byte alignment @p ByteAlignment is reached. 226 /// 227 /// If the number of bytes need to emit for the alignment is not a multiple 228 /// of @p ValueSize, then the contents of the emitted fill bytes is 229 /// undefined. 230 /// 231 /// This used to implement the .align assembler directive. 232 /// 233 /// @param ByteAlignment - The alignment to reach. This must be a power of 234 /// two on some targets. 235 /// @param Value - The value to use when filling bytes. 236 /// @param ValueSize - The size of the integer (in bytes) to emit for 237 /// @p Value. This must match a native machine width. 238 /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If 239 /// the alignment cannot be reached in this many bytes, no bytes are 240 /// emitted. 241 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0, 242 unsigned ValueSize = 1, 243 unsigned MaxBytesToEmit = 0) = 0; 244 245 /// EmitCodeAlignment - Emit nops until the byte alignment @p ByteAlignment 246 /// is reached. 247 /// 248 /// This used to align code where the alignment bytes may be executed. This 249 /// can emit different bytes for different sizes to optimize execution. 250 /// 251 /// @param ByteAlignment - The alignment to reach. This must be a power of 252 /// two on some targets. 253 /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If 254 /// the alignment cannot be reached in this many bytes, no bytes are 255 /// emitted. 256 virtual void EmitCodeAlignment(unsigned ByteAlignment, 257 unsigned MaxBytesToEmit = 0) = 0; 258 259 /// EmitValueToOffset - Emit some number of copies of @p Value until the 260 /// byte offset @p Offset is reached. 261 /// 262 /// This is used to implement assembler directives such as .org. 263 /// 264 /// @param Offset - The offset to reach. This may be an expression, but the 265 /// expression must be associated with the current section. 266 /// @param Value - The value to use when filling bytes. 267 virtual void EmitValueToOffset(const MCExpr *Offset, 268 unsigned char Value = 0) = 0; 269 270 /// @} 271 272 /// EmitFileDirective - Switch to a new logical file. This is used to 273 /// implement the '.file "foo.c"' assembler directive. 274 virtual void EmitFileDirective(StringRef Filename) = 0; 275 276 /// EmitDwarfFileDirective - Associate a filename with a specified logical 277 /// file number. This implements the DWARF2 '.file 4 "foo.c"' assembler 278 /// directive. 279 virtual void EmitDwarfFileDirective(unsigned FileNo,StringRef Filename) = 0; 280 281 /// EmitInstruction - Emit the given @p Instruction into the current 282 /// section. 283 virtual void EmitInstruction(const MCInst &Inst) = 0; 284 285 /// EmitRawText - If this file is backed by a assembly streamer, this dumps 286 /// the specified string in the output .s file. This capability is 287 /// indicated by the hasRawTextSupport() predicate. By default this aborts. 288 virtual void EmitRawText(StringRef String); 289 290 /// Finish - Finish emission of machine code and flush any output. 291 virtual void Finish() = 0; 292 }; 293 294 /// createNullStreamer - Create a dummy machine code streamer, which does 295 /// nothing. This is useful for timing the assembler front end. 296 MCStreamer *createNullStreamer(MCContext &Ctx); 297 298 /// createAsmStreamer - Create a machine code streamer which will print out 299 /// assembly for the native target, suitable for compiling with a native 300 /// assembler. 301 /// 302 /// \param InstPrint - If given, the instruction printer to use. If not given 303 /// the MCInst representation will be printed. This method takes ownership of 304 /// InstPrint. 305 /// 306 /// \param CE - If given, a code emitter to use to show the instruction 307 /// encoding inline with the assembly. 308 /// 309 /// \param ShowInst - Whether to show the MCInst representation inline with 310 /// the assembly. 311 MCStreamer *createAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS, 312 bool isLittleEndian, bool isVerboseAsm, 313 MCInstPrinter *InstPrint = 0, 314 MCCodeEmitter *CE = 0, 315 bool ShowInst = false); 316 317 /// createMachOStream - Create a machine code streamer which will generative 318 /// Mach-O format object files. 319 MCStreamer *createMachOStreamer(MCContext &Ctx, TargetAsmBackend &TAB, 320 raw_ostream &OS, MCCodeEmitter *CE, 321 bool RelaxAll = false); 322 323} // end namespace llvm 324 325#endif 326