MCAsmStreamer.cpp revision c22e0b2443afdedb6d9b225b938ad404d63cdbe6 
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/CodeGen/AsmPrinter.h"
13#include "llvm/MC/MCContext.h"
14#include "llvm/MC/MCInst.h"
15#include "llvm/MC/MCSectionMachO.h"
16#include "llvm/MC/MCSymbol.h"
17#include "llvm/MC/MCValue.h"
18#include "llvm/Support/ErrorHandling.h"
19#include "llvm/Support/raw_ostream.h"
20
21using namespace llvm;
22
23namespace {
24
25  class MCAsmStreamer : public MCStreamer {
26    raw_ostream &OS;
27
28    AsmPrinter *Printer;
29
30    MCSection *CurSection;
31
32  public:
33    MCAsmStreamer(MCContext &Context, raw_ostream &_OS, AsmPrinter *_AsmPrinter)
34      : MCStreamer(Context), OS(_OS), Printer(_AsmPrinter), CurSection(0) {}
35    ~MCAsmStreamer() {}
36
37    /// @name MCStreamer Interface
38    /// @{
39
40    virtual void SwitchSection(MCSection *Section);
41
42    virtual void EmitLabel(MCSymbol *Symbol);
43
44    virtual void EmitAssemblerFlag(AssemblerFlag Flag);
45
46    virtual void EmitAssignment(MCSymbol *Symbol, const MCValue &Value,
47                                bool MakeAbsolute = false);
48
49    virtual void EmitSymbolAttribute(MCSymbol *Symbol, SymbolAttr Attribute);
50
51    virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
52
53    virtual void EmitLocalSymbol(MCSymbol *Symbol, const MCValue &Value);
54
55    virtual void EmitCommonSymbol(MCSymbol *Symbol, unsigned Size,
56                                  unsigned Pow2Alignment, bool IsLocal);
57
58    virtual void EmitZerofill(MCSection *Section, MCSymbol *Symbol = NULL,
59                              unsigned Size = 0, unsigned Pow2Alignment = 0);
60
61    virtual void EmitBytes(const StringRef &Data);
62
63    virtual void EmitValue(const MCValue &Value, unsigned Size);
64
65    virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
66                                      unsigned ValueSize = 1,
67                                      unsigned MaxBytesToEmit = 0);
68
69    virtual void EmitValueToOffset(const MCValue &Offset,
70                                   unsigned char Value = 0);
71
72    virtual void EmitInstruction(const MCInst &Inst);
73
74    virtual void Finish();
75
76    /// @}
77  };
78
79}
80
81/// Allow printing symbols directly to a raw_ostream with proper quoting.
82static inline raw_ostream &operator<<(raw_ostream &os, const MCSymbol *S) {
83  S->print(os);
84
85  return os;
86}
87
88/// Allow printing values directly to a raw_ostream.
89static inline raw_ostream &operator<<(raw_ostream &os, const MCValue &Value) {
90  Value.print(os);
91
92  return os;
93}
94
95static inline int64_t truncateToSize(int64_t Value, unsigned Bytes) {
96  assert(Bytes && "Invalid size!");
97  return Value & ((uint64_t) (int64_t) -1 >> (64 - Bytes * 8));
98}
99
100static inline MCValue truncateToSize(const MCValue &Value, unsigned Bytes) {
101  return MCValue::get(Value.getSymA(), Value.getSymB(),
102                      truncateToSize(Value.getConstant(), Bytes));
103}
104
105void MCAsmStreamer::SwitchSection(MCSection *Section) {
106  if (Section != CurSection) {
107    CurSection = Section;
108
109    // FIXME: Needs TargetAsmInfo!
110    Section->PrintSwitchToSection(*(const TargetAsmInfo*)0, OS);
111  }
112}
113
114void MCAsmStreamer::EmitLabel(MCSymbol *Symbol) {
115  assert(Symbol->getSection() == 0 && "Cannot emit a symbol twice!");
116  assert(CurSection && "Cannot emit before setting section!");
117  assert(!getContext().GetSymbolValue(Symbol) &&
118         "Cannot emit symbol which was directly assigned to!");
119
120  OS << Symbol << ":\n";
121  Symbol->setSection(CurSection);
122  Symbol->setExternal(false);
123}
124
125void MCAsmStreamer::EmitAssemblerFlag(AssemblerFlag Flag) {
126  switch (Flag) {
127  default: assert(0 && "Invalid flag!");
128  case SubsectionsViaSymbols: OS << ".subsections_via_symbols"; break;
129  }
130  OS << '\n';
131}
132
133void MCAsmStreamer::EmitAssignment(MCSymbol *Symbol, const MCValue &Value,
134                                   bool MakeAbsolute) {
135  assert(!Symbol->getSection() && "Cannot assign to a label!");
136
137  if (MakeAbsolute) {
138    OS << ".set " << Symbol << ", " << Value << '\n';
139  } else {
140    OS << Symbol << " = " << Value << '\n';
141  }
142
143  getContext().SetSymbolValue(Symbol, Value);
144}
145
146void MCAsmStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
147                                        SymbolAttr Attribute) {
148  switch (Attribute) {
149  case Global: OS << ".globl"; break;
150  case Hidden: OS << ".hidden"; break;
151  case IndirectSymbol: OS << ".indirect_symbol"; break;
152  case Internal: OS << ".internal"; break;
153  case LazyReference: OS << ".lazy_reference"; break;
154  case NoDeadStrip: OS << ".no_dead_strip"; break;
155  case PrivateExtern: OS << ".private_extern"; break;
156  case Protected: OS << ".protected"; break;
157  case Reference: OS << ".reference"; break;
158  case Weak: OS << ".weak"; break;
159  case WeakDefinition: OS << ".weak_definition"; break;
160  case WeakReference: OS << ".weak_reference"; break;
161  }
162
163  OS << ' ' << Symbol << '\n';
164}
165
166void MCAsmStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
167  OS << ".desc" << ' ' << Symbol << ',' << DescValue << '\n';
168}
169
170void MCAsmStreamer::EmitLocalSymbol(MCSymbol *Symbol, const MCValue &Value) {
171  OS << ".lsym" << ' ' << Symbol << ',' << Value << '\n';
172}
173
174void MCAsmStreamer::EmitCommonSymbol(MCSymbol *Symbol, unsigned Size,
175                                     unsigned Pow2Alignment, bool IsLocal) {
176  if (IsLocal)
177    OS << ".lcomm";
178  else
179    OS << ".comm";
180  OS << ' ' << Symbol << ',' << Size;
181  if (Pow2Alignment != 0)
182    OS << ',' << Pow2Alignment;
183  OS << '\n';
184}
185
186void MCAsmStreamer::EmitZerofill(MCSection *Section, MCSymbol *Symbol,
187                                 unsigned Size, unsigned Pow2Alignment) {
188  // Note: a .zerofill directive does not switch sections.
189  OS << ".zerofill ";
190
191  // This is a mach-o specific directive.
192  const MCSectionMachO *MOSection = ((const MCSectionMachO*)Section);
193  OS << '"' << MOSection->getSegmentName() << ","
194     << MOSection->getSectionName() << '"';
195
196  if (Symbol != NULL) {
197    OS << ',' << Symbol << ',' << Size;
198    if (Pow2Alignment != 0)
199      OS << ',' << Pow2Alignment;
200  }
201  OS << '\n';
202}
203
204void MCAsmStreamer::EmitBytes(const StringRef &Data) {
205  assert(CurSection && "Cannot emit contents before setting section!");
206  for (unsigned i = 0, e = Data.size(); i != e; ++i)
207    OS << ".byte " << (unsigned) Data[i] << '\n';
208}
209
210void MCAsmStreamer::EmitValue(const MCValue &Value, unsigned Size) {
211  assert(CurSection && "Cannot emit contents before setting section!");
212  // Need target hooks to know how to print this.
213  switch (Size) {
214  default:
215    llvm_unreachable("Invalid size for machine code value!");
216  case 1: OS << ".byte"; break;
217  case 2: OS << ".short"; break;
218  case 4: OS << ".long"; break;
219  case 8: OS << ".quad"; break;
220  }
221
222  OS << ' ' << truncateToSize(Value, Size) << '\n';
223}
224
225void MCAsmStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
226                                         unsigned ValueSize,
227                                         unsigned MaxBytesToEmit) {
228  // Some assemblers don't support .balign, so we always emit as .p2align if
229  // this is a power of two. Otherwise we assume the client knows the target
230  // supports .balign and use that.
231  unsigned Pow2 = Log2_32(ByteAlignment);
232  bool IsPow2 = (1U << Pow2) == ByteAlignment;
233
234  switch (ValueSize) {
235  default:
236    llvm_unreachable("Invalid size for machine code value!");
237  case 8:
238    llvm_unreachable("Unsupported alignment size!");
239  case 1: OS << (IsPow2 ? ".p2align" : ".balign"); break;
240  case 2: OS << (IsPow2 ? ".p2alignw" : ".balignw"); break;
241  case 4: OS << (IsPow2 ? ".p2alignl" : ".balignl"); break;
242  }
243
244  OS << ' ' << (IsPow2 ? Pow2 : ByteAlignment);
245
246  OS << ", " << truncateToSize(Value, ValueSize);
247  if (MaxBytesToEmit)
248    OS << ", " << MaxBytesToEmit;
249  OS << '\n';
250}
251
252void MCAsmStreamer::EmitValueToOffset(const MCValue &Offset,
253                                      unsigned char Value) {
254  // FIXME: Verify that Offset is associated with the current section.
255  OS << ".org " << Offset << ", " << (unsigned) Value << '\n';
256}
257
258static raw_ostream &operator<<(raw_ostream &OS, const MCOperand &Op) {
259  if (Op.isReg())
260    return OS << "reg:" << Op.getReg();
261  if (Op.isImm())
262    return OS << "imm:" << Op.getImm();
263  if (Op.isMBBLabel())
264    return OS << "mbblabel:("
265              << Op.getMBBLabelFunction() << ", " << Op.getMBBLabelBlock();
266  assert(Op.isMCValue() && "Invalid operand!");
267  return OS << "val:" << Op.getMCValue();
268}
269
270void MCAsmStreamer::EmitInstruction(const MCInst &Inst) {
271  assert(CurSection && "Cannot emit contents before setting section!");
272
273  // If we have an AsmPrinter, use that to print.
274  if (Printer) {
275    Printer->printMCInst(&Inst);
276    return;
277  }
278
279  // Otherwise fall back to a structural printing for now. Eventually we should
280  // always have access to the target specific printer.
281  OS << "MCInst("
282     << "opcode=" << Inst.getOpcode() << ", "
283     << "operands=[";
284  for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i) {
285    if (i)
286      OS << ", ";
287    OS << Inst.getOperand(i);
288  }
289  OS << "])\n";
290}
291
292void MCAsmStreamer::Finish() {
293  OS.flush();
294}
295
296MCStreamer *llvm::createAsmStreamer(MCContext &Context, raw_ostream &OS,
297                                    AsmPrinter *AP) {
298  return new MCAsmStreamer(Context, OS, AP);
299}
300