MCStreamer.h revision fdab14b10564283028e9bdb628d095feae7fa071
15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)//===- MCStreamer.h - High-level Streaming Machine Code Output --*- C++ -*-===// 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// The LLVM Compiler Infrastructure 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 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 at 66 /// all. 67 virtual bool isVerboseAsm() const { return false; } 68 69 /// AddComment - Add a comment that can be emitted to the generated .s 70 /// file if applicable as a QoI issue to make the output of the compiler 71 /// more readable. This only affects the MCAsmStreamer, and only when 72 /// verbose assembly output is enabled. 73 /// 74 /// If the comment includes embedded \n's, they will each get the comment 75 /// prefix as appropriate. The added comment should not end with a \n. 76 virtual void AddComment(const Twine &T) {} 77 78 /// GetCommentOS - Return a raw_ostream that comments can be written to. 79 /// Unlike AddComment, you are required to terminate comments with \n if you 80 /// use this method. 81 virtual raw_ostream &GetCommentOS(); 82 83 /// AddBlankLine - Emit a blank line to a .s file to pretty it up. 84 virtual void AddBlankLine() {} 85 86 /// @} 87 88 /// @name Symbol & Section Management 89 /// @{ 90 91 /// getCurrentSection - Return the current seciton that the streamer is 92 /// emitting code to. 93 const MCSection *getCurrentSection() const { return CurSection; } 94 95 /// SwitchSection - Set the current section where code is being emitted to 96 /// @p Section. This is required to update CurSection. 97 /// 98 /// This corresponds to assembler directives like .section, .text, etc. 99 virtual void SwitchSection(const MCSection *Section) = 0; 100 101 /// EmitLabel - Emit a label for @p Symbol into the current section. 102 /// 103 /// This corresponds to an assembler statement such as: 104 /// foo: 105 /// 106 /// @param Symbol - The symbol to emit. A given symbol should only be 107 /// emitted as a label once, and symbols emitted as a label should never be 108 /// used in an assignment. 109 virtual void EmitLabel(MCSymbol *Symbol) = 0; 110 111 /// EmitAssemblerFlag - Note in the output the specified @p Flag 112 virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) = 0; 113 114 /// EmitAssignment - Emit an assignment of @p Value to @p Symbol. 115 /// 116 /// This corresponds to an assembler statement such as: 117 /// symbol = value 118 /// 119 /// The assignment generates no code, but has the side effect of binding the 120 /// value in the current context. For the assembly streamer, this prints the 121 /// binding into the .s file. 122 /// 123 /// @param Symbol - The symbol being assigned to. 124 /// @param Value - The value for the symbol. 125 virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) = 0; 126 127 /// EmitSymbolAttribute - Add the given @p Attribute to @p Symbol. 128 virtual void EmitSymbolAttribute(MCSymbol *Symbol, 129 MCSymbolAttr Attribute) = 0; 130 131 /// EmitSymbolDesc - Set the @p DescValue for the @p Symbol. 132 /// 133 /// @param Symbol - The symbol to have its n_desc field set. 134 /// @param DescValue - The value to set into the n_desc field. 135 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) = 0; 136 137 138 /// EmitELFSize - Emit an ELF .size directive. 139 /// 140 /// This corresponds to an assembler statement such as: 141 /// .size symbol, expression 142 /// 143 virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) = 0; 144 145 /// EmitCommonSymbol - Emit a common symbol. 146 /// 147 /// @param Symbol - The common symbol to emit. 148 /// @param Size - The size of the common symbol. 149 /// @param ByteAlignment - The alignment of the symbol if 150 /// non-zero. This must be a power of 2. 151 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size, 152 unsigned ByteAlignment) = 0; 153 154 /// EmitLocalCommonSymbol - Emit a local common (.lcomm) symbol. 155 /// 156 /// @param Symbol - The common symbol to emit. 157 /// @param Size - The size of the common symbol. 158 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) = 0; 159 160 /// EmitZerofill - Emit a the zerofill section and an option symbol. 161 /// 162 /// @param Section - The zerofill section to create and or to put the symbol 163 /// @param Symbol - The zerofill symbol to emit, if non-NULL. 164 /// @param Size - The size of the zerofill symbol. 165 /// @param ByteAlignment - The alignment of the zerofill symbol if 166 /// non-zero. This must be a power of 2 on some targets. 167 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0, 168 unsigned Size = 0,unsigned ByteAlignment = 0) = 0; 169 170 /// @} 171 /// @name Generating Data 172 /// @{ 173 174 /// EmitBytes - Emit the bytes in \arg Data into the output. 175 /// 176 /// This is used to implement assembler directives such as .byte, .ascii, 177 /// etc. 178 virtual void EmitBytes(StringRef Data, unsigned AddrSpace) = 0; 179 180 /// EmitValue - Emit the expression @p Value into the output as a native 181 /// integer of the given @p Size bytes. 182 /// 183 /// This is used to implement assembler directives such as .word, .quad, 184 /// etc. 185 /// 186 /// @param Value - The value to emit. 187 /// @param Size - The size of the integer (in bytes) to emit. This must 188 /// match a native machine width. 189 virtual void EmitValue(const MCExpr *Value, unsigned Size, 190 unsigned AddrSpace) = 0; 191 192 /// EmitIntValue - Special case of EmitValue that avoids the client having 193 /// to pass in a MCExpr for constant integers. 194 virtual void EmitIntValue(uint64_t Value, unsigned Size,unsigned AddrSpace); 195 196 /// EmitSymbolValue - Special case of EmitValue that avoids the client 197 /// having to pass in a MCExpr for MCSymbols. 198 virtual void EmitSymbolValue(const MCSymbol *Sym, unsigned Size, 199 unsigned AddrSpace); 200 201 /// EmitGPRel32Value - Emit the expression @p Value into the output as a 202 /// gprel32 (32-bit GP relative) value. 203 /// 204 /// This is used to implement assembler directives such as .gprel32 on 205 /// targets that support them. 206 virtual void EmitGPRel32Value(const MCExpr *Value) = 0; 207 208 /// EmitFill - Emit NumBytes bytes worth of the value specified by 209 /// FillValue. This implements directives such as '.space'. 210 virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue, 211 unsigned AddrSpace); 212 213 /// EmitZeros - Emit NumBytes worth of zeros. This is a convenience 214 /// function that just wraps EmitFill. 215 void EmitZeros(uint64_t NumBytes, unsigned AddrSpace) { 216 EmitFill(NumBytes, 0, AddrSpace); 217 } 218 219 220 /// EmitValueToAlignment - Emit some number of copies of @p Value until 221 /// the byte alignment @p ByteAlignment is reached. 222 /// 223 /// If the number of bytes need to emit for the alignment is not a multiple 224 /// of @p ValueSize, then the contents of the emitted fill bytes is 225 /// undefined. 226 /// 227 /// This used to implement the .align assembler directive. 228 /// 229 /// @param ByteAlignment - The alignment to reach. This must be a power of 230 /// two on some targets. 231 /// @param Value - The value to use when filling bytes. 232 /// @param ValueSize - The size of the integer (in bytes) to emit for 233 /// @p Value. This must match a native machine width. 234 /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If 235 /// the alignment cannot be reached in this many bytes, no bytes are 236 /// emitted. 237 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0, 238 unsigned ValueSize = 1, 239 unsigned MaxBytesToEmit = 0) = 0; 240 241 /// EmitCodeAlignment - Emit nops until the byte alignment @p ByteAlignment 242 /// is reached. 243 /// 244 /// This used to align code where the alignment bytes may be executed. This 245 /// can emit different bytes for different sizes to optimize execution. 246 /// 247 /// @param ByteAlignment - The alignment to reach. This must be a power of 248 /// two on some targets. 249 /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If 250 /// the alignment cannot be reached in this many bytes, no bytes are 251 /// emitted. 252 virtual void EmitCodeAlignment(unsigned ByteAlignment, 253 unsigned MaxBytesToEmit = 0) = 0; 254 255 /// EmitValueToOffset - Emit some number of copies of @p Value until the 256 /// byte offset @p Offset is reached. 257 /// 258 /// This is used to implement assembler directives such as .org. 259 /// 260 /// @param Offset - The offset to reach. This may be an expression, but the 261 /// expression must be associated with the current section. 262 /// @param Value - The value to use when filling bytes. 263 virtual void EmitValueToOffset(const MCExpr *Offset, 264 unsigned char Value = 0) = 0; 265 266 /// @} 267 268 /// EmitFileDirective - Switch to a new logical file. This is used to 269 /// implement the '.file "foo.c"' assembler directive. 270 virtual void EmitFileDirective(StringRef Filename) = 0; 271 272 /// EmitDwarfFileDirective - Associate a filename with a specified logical 273 /// file number. This implements the DWARF2 '.file 4 "foo.c"' assembler 274 /// directive. 275 virtual void EmitDwarfFileDirective(unsigned FileNo,StringRef Filename) = 0; 276 277 /// EmitInstruction - Emit the given @p Instruction into the current 278 /// section. 279 virtual void EmitInstruction(const MCInst &Inst) = 0; 280 281 /// Finish - Finish emission of machine code and flush any output. 282 virtual void Finish() = 0; 283 }; 284 285 /// createNullStreamer - Create a dummy machine code streamer, which does 286 /// nothing. This is useful for timing the assembler front end. 287 MCStreamer *createNullStreamer(MCContext &Ctx); 288 289 /// createAsmStreamer - Create a machine code streamer which will print out 290 /// assembly for the native target, suitable for compiling with a native 291 /// assembler. 292 /// 293 /// \param InstPrint - If given, the instruction printer to use. If not given 294 /// the MCInst representation will be printed. 295 /// 296 /// \param CE - If given, a code emitter to use to show the instruction 297 /// encoding inline with the assembly. 298 /// 299 /// \param ShowInst - Whether to show the MCInst representation inline with 300 /// the assembly. 301 MCStreamer *createAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS, 302 bool isLittleEndian, bool isVerboseAsm, 303 MCInstPrinter *InstPrint = 0, 304 MCCodeEmitter *CE = 0, 305 bool ShowInst = false); 306 307 /// createMachOStream - Create a machine code streamer which will generative 308 /// Mach-O format object files. 309 MCStreamer *createMachOStreamer(MCContext &Ctx, TargetAsmBackend &TAB, 310 raw_ostream &OS, MCCodeEmitter *CE); 311 312} // end namespace llvm 313 314#endif 315