lib/MC/MCAsmStreamer.cpp

   1 //===- lib/MC/MCAsmStreamer.cpp - Text Assembly Output --------------------===//
   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 #include "llvm/MC/MCStreamer.h"
  11
  12 #include "llvm/MC/MCContext.h"
  13 #include "llvm/MC/MCInst.h"
  14 #include "llvm/MC/MCSection.h"
  15 #include "llvm/MC/MCSymbol.h"
  16 #include "llvm/MC/MCValue.h"
  17 #include "llvm/Support/ErrorHandling.h"
  18 #include "llvm/Support/raw_ostream.h"
  19
  20 using namespace llvm;
  21
  22 namespace {
  23
  24   class MCAsmStreamer : public MCStreamer {
  25     raw_ostream &OS;
  26
  27     MCSection *CurSection;
  28
  29   public:
  30     MCAsmStreamer(MCContext &Context, raw_ostream &_OS)
  31       : MCStreamer(Context), OS(_OS), CurSection(0) {}
  32     ~MCAsmStreamer() {}
  33
  34     /// @name MCStreamer Interface
  35     /// @{
  36
  37     virtual void SwitchSection(MCSection *Section);
  38
  39     virtual void EmitLabel(MCSymbol *Symbol);
  40
  41     virtual void EmitAssemblerFlag(AssemblerFlag Flag);
  42
  43     virtual void EmitAssignment(MCSymbol *Symbol, const MCValue &Value,
  44                                 bool MakeAbsolute = false);
  45
  46     virtual void EmitSymbolAttribute(MCSymbol *Symbol, SymbolAttr Attribute);
  47
  48     virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
  49
  50     virtual void EmitLocalSymbol(MCSymbol *Symbol, const MCValue &Value);
  51
  52     virtual void EmitCommonSymbol(MCSymbol *Symbol, unsigned Size,
  53                                   unsigned Pow2Alignment, bool IsLocal);
  54
  55     virtual void EmitZerofill(MCSection *Section, MCSymbol *Symbol = NULL,
  56                               unsigned Size = 0, unsigned Pow2Alignment = 0);
  57
  58     virtual void EmitBytes(const StringRef &Data);
  59
  60     virtual void EmitValue(const MCValue &Value, unsigned Size);
  61
  62     virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
  63                                       unsigned ValueSize = 1,
  64                                       unsigned MaxBytesToEmit = 0);
  65
  66     virtual void EmitValueToOffset(const MCValue &Offset,
  67                                    unsigned char Value = 0);
  68
  69     virtual void EmitInstruction(const MCInst &Inst);
  70
  71     virtual void Finish();
  72
  73     /// @}
  74   };
  75
  76 }
  77
  78 /// NeedsQuoting - Return true if the string \arg Str needs quoting, i.e., it
  79 /// does not match [a-zA-Z_.][a-zA-Z0-9_.]*.
  80 //
  81 // FIXME: This could be more permissive, do we care?
  82 static inline bool NeedsQuoting(const StringRef &Str) {
  83   if (Str.empty())
  84     return true;
  85
  86   // Check that first character is in [a-zA-Z_.].
  87   if (!((Str[0] >= 'a' && Str[0] <= 'z') ||
  88         (Str[0] >= 'A' && Str[0] <= 'Z') ||
  89         (Str[0] == '_' || Str[0] == '.')))
  90     return true;
  91
  92   // Check subsequent characters are in [a-zA-Z0-9_.].
  93   for (unsigned i = 1, e = Str.size(); i != e; ++i)
  94     if (!((Str[i] >= 'a' && Str[i] <= 'z') ||
  95           (Str[i] >= 'A' && Str[i] <= 'Z') ||
  96           (Str[i] >= '0' && Str[i] <= '9') ||
  97           (Str[i] == '_' || Str[i] == '.')))
  98       return true;
  99
 100   return false;
 101 }
 102
 103 /// Allow printing sections directly to a raw_ostream with proper quoting.
 104 static inline raw_ostream &operator<<(raw_ostream &os, const MCSection *S) {
 105   if (NeedsQuoting(S->getName()))
 106     return os << '"' << S->getName() << '"';
 107   return os << S->getName();
 108 }
 109
 110 /// Allow printing symbols directly to a raw_ostream with proper quoting.
 111 static inline raw_ostream &operator<<(raw_ostream &os, const MCSymbol *S) {
 112   if (NeedsQuoting(S->getName()))
 113     return os << '"' << S->getName() << '"';
 114   return os << S->getName();
 115 }
 116
 117 /// Allow printing values directly to a raw_ostream.
 118 static inline raw_ostream &operator<<(raw_ostream &os, const MCValue &Value) {
 119   if (Value.getSymA()) {
 120     os << Value.getSymA();
 121     if (Value.getSymB())
 122       os << " - " << Value.getSymB();
 123     if (Value.getConstant())
 124       os << " + " << Value.getConstant();
 125   } else {
 126     assert(!Value.getSymB() && "Invalid machine code value!");
 127     os << Value.getConstant();
 128   }
 129
 130   return os;
 131 }
 132
 133 static inline int64_t truncateToSize(int64_t Value, unsigned Bytes) {
 134   assert(Bytes && "Invalid size!");
 135   return Value & ((uint64_t) (int64_t) -1 >> (64 - Bytes * 8));
 136 }
 137
 138 static inline MCValue truncateToSize(const MCValue &Value, unsigned Bytes) {
 139   return MCValue::get(Value.getSymA(), Value.getSymB(),
 140                       truncateToSize(Value.getConstant(), Bytes));
 141 }
 142
 143 void MCAsmStreamer::SwitchSection(MCSection *Section) {
 144   if (Section != CurSection) {
 145     CurSection = Section;
 146
 147     // FIXME: Really we would like the segment, flags, etc. to be separate
 148     // values instead of embedded in the name. Not all assemblers understand all
 149     // this stuff though.
 150     OS << ".section " << Section << "\n";
 151   }
 152 }
 153
 154 void MCAsmStreamer::EmitLabel(MCSymbol *Symbol) {
 155   assert(Symbol->getSection() == 0 && "Cannot emit a symbol twice!");
 156   assert(CurSection && "Cannot emit before setting section!");
 157   assert(!getContext().GetSymbolValue(Symbol) &&
 158          "Cannot emit symbol which was directly assigned to!");
 159
 160   OS << Symbol << ":\n";
 161   Symbol->setSection(CurSection);
 162   Symbol->setExternal(false);
 163 }
 164
 165 void MCAsmStreamer::EmitAssemblerFlag(AssemblerFlag Flag) {
 166   switch (Flag) {
 167   case SubsectionsViaSymbols: OS << ".subsections_via_symbols"; break;
 168   }
 169   OS << '\n';
 170 }
 171
 172 void MCAsmStreamer::EmitAssignment(MCSymbol *Symbol, const MCValue &Value,
 173                                    bool MakeAbsolute) {
 174   assert(!Symbol->getSection() && "Cannot assign to a label!");
 175
 176   if (MakeAbsolute) {
 177     OS << ".set " << Symbol << ", " << Value << '\n';
 178   } else {
 179     OS << Symbol << " = " << Value << '\n';
 180   }
 181
 182   getContext().SetSymbolValue(Symbol, Value);
 183 }
 184
 185 void MCAsmStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
 186                                         SymbolAttr Attribute) {
 187   switch (Attribute) {
 188   case Global: OS << ".globl"; break;
 189   case Hidden: OS << ".hidden"; break;
 190   case IndirectSymbol: OS << ".indirect_symbol"; break;
 191   case Internal: OS << ".internal"; break;
 192   case LazyReference: OS << ".lazy_reference"; break;
 193   case NoDeadStrip: OS << ".no_dead_strip"; break;
 194   case PrivateExtern: OS << ".private_extern"; break;
 195   case Protected: OS << ".protected"; break;
 196   case Reference: OS << ".reference"; break;
 197   case Weak: OS << ".weak"; break;
 198   case WeakDefinition: OS << ".weak_definition"; break;
 199   case WeakReference: OS << ".weak_reference"; break;
 200   }
 201
 202   OS << ' ' << Symbol << '\n';
 203 }
 204
 205 void MCAsmStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
 206   OS << ".desc" << ' ' << Symbol << ',' << DescValue << '\n';
 207 }
 208
 209 void MCAsmStreamer::EmitLocalSymbol(MCSymbol *Symbol, const MCValue &Value) {
 210   OS << ".lsym" << ' ' << Symbol << ',' << Value << '\n';
 211 }
 212
 213 void MCAsmStreamer::EmitCommonSymbol(MCSymbol *Symbol, unsigned Size,
 214                                      unsigned Pow2Alignment, bool IsLocal) {
 215   if (IsLocal)
 216     OS << ".lcomm";
 217   else
 218     OS << ".comm";
 219   OS << ' ' << Symbol << ',' << Size;
 220   if (Pow2Alignment != 0)
 221     OS << ',' << Pow2Alignment;
 222   OS << '\n';
 223 }
 224
 225 void MCAsmStreamer::EmitZerofill(MCSection *Section, MCSymbol *Symbol,
 226                                  unsigned Size, unsigned Pow2Alignment) {
 227   // Note: a .zerofill directive does not switch sections
 228   // FIXME: Really we would like the segment and section names as well as the
 229   // section type to be separate values instead of embedded in the name. Not
 230   // all assemblers understand all this stuff though.
 231   OS << ".zerofill " << Section;
 232   if (Symbol != NULL) {
 233     OS << ',' << Symbol << ',' << Size;
 234     if (Pow2Alignment != 0)
 235       OS << ',' << Pow2Alignment;
 236   }
 237   OS << '\n';
 238 }
 239
 240 void MCAsmStreamer::EmitBytes(const StringRef &Data) {
 241   assert(CurSection && "Cannot emit contents before setting section!");
 242   for (unsigned i = 0, e = Data.size(); i != e; ++i)
 243     OS << ".byte " << (unsigned) Data[i] << '\n';
 244 }
 245
 246 void MCAsmStreamer::EmitValue(const MCValue &Value, unsigned Size) {
 247   assert(CurSection && "Cannot emit contents before setting section!");
 248   // Need target hooks to know how to print this.
 249   switch (Size) {
 250   default:
 251     llvm_unreachable("Invalid size for machine code value!");
 252   case 1: OS << ".byte"; break;
 253   case 2: OS << ".short"; break;
 254   case 4: OS << ".long"; break;
 255   case 8: OS << ".quad"; break;
 256   }
 257
 258   OS << ' ' << truncateToSize(Value, Size) << '\n';
 259 }
 260
 261 void MCAsmStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
 262                                          unsigned ValueSize,
 263                                          unsigned MaxBytesToEmit) {
 264   // Some assemblers don't support .balign, so we always emit as .p2align if
 265   // this is a power of two. Otherwise we assume the client knows the target
 266   // supports .balign and use that.
 267   unsigned Pow2 = Log2_32(ByteAlignment);
 268   bool IsPow2 = (1U << Pow2) == ByteAlignment;
 269
 270   switch (ValueSize) {
 271   default:
 272     llvm_unreachable("Invalid size for machine code value!");
 273   case 8:
 274     llvm_unreachable("Unsupported alignment size!");
 275   case 1: OS << (IsPow2 ? ".p2align" : ".balign"); break;
 276   case 2: OS << (IsPow2 ? ".p2alignw" : ".balignw"); break;
 277   case 4: OS << (IsPow2 ? ".p2alignl" : ".balignl"); break;
 278   }
 279
 280   OS << ' ' << (IsPow2 ? Pow2 : ByteAlignment);
 281
 282   OS << ", " << truncateToSize(Value, ValueSize);
 283   if (MaxBytesToEmit)
 284     OS << ", " << MaxBytesToEmit;
 285   OS << '\n';
 286 }
 287
 288 void MCAsmStreamer::EmitValueToOffset(const MCValue &Offset,
 289                                       unsigned char Value) {
 290   // FIXME: Verify that Offset is associated with the current section.
 291   OS << ".org " << Offset << ", " << (unsigned) Value << '\n';
 292 }
 293
 294 static raw_ostream &operator<<(raw_ostream &OS, const MCOperand &Op) {
 295   if (Op.isReg())
 296     return OS << "reg:" << Op.getReg();
 297   if (Op.isImm())
 298     return OS << "imm:" << Op.getImm();
 299   if (Op.isMBBLabel())
 300     return OS << "mbblabel:("
 301               << Op.getMBBLabelFunction() << ", " << Op.getMBBLabelBlock();
 302   assert(Op.isMCValue() && "Invalid operand!");
 303   return OS << "val:" << Op.getMCValue();
 304 }
 305
 306 void MCAsmStreamer::EmitInstruction(const MCInst &Inst) {
 307   assert(CurSection && "Cannot emit contents before setting section!");
 308   // FIXME: Implement proper printing.
 309   OS << "MCInst("
 310      << "opcode=" << Inst.getOpcode() << ", "
 311      << "operands=[";
 312   for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i) {
 313     if (i)
 314       OS << ", ";
 315     OS << Inst.getOperand(i);
 316   }
 317   OS << "])\n";
 318 }
 319
 320 void MCAsmStreamer::Finish() {
 321   OS.flush();
 322 }
 323
 324 MCStreamer *llvm::createAsmStreamer(MCContext &Context, raw_ostream &OS) {
 325   return new MCAsmStreamer(Context, OS);
 326 }