1 //===- lib/MC/MCAsmStreamer.cpp - Text Assembly Output --------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/MC/MCStreamer.h"
11 #include "llvm/ADT/SmallString.h"
12 #include "llvm/MC/MCAsmInfo.h"
13 #include "llvm/MC/MCCodeEmitter.h"
14 #include "llvm/MC/MCContext.h"
15 #include "llvm/MC/MCExpr.h"
16 #include "llvm/MC/MCInst.h"
17 #include "llvm/MC/MCInstPrinter.h"
18 #include "llvm/MC/MCSectionMachO.h"
19 #include "llvm/MC/MCSymbol.h"
20 #include "llvm/Support/ErrorHandling.h"
21 #include "llvm/Support/MathExtras.h"
22 #include "llvm/Support/Format.h"
23 #include "llvm/Support/raw_ostream.h"
28 class MCAsmStreamer : public MCStreamer {
31 MCInstPrinter *InstPrinter;
32 MCCodeEmitter *Emitter;
34 MCAsmStreamer(MCContext &Context, raw_ostream &_OS, const MCAsmInfo &tai,
35 MCInstPrinter *_Printer, MCCodeEmitter *_Emitter)
36 : MCStreamer(Context), OS(_OS), MAI(tai), InstPrinter(_Printer),
40 /// @name MCStreamer Interface
43 virtual void SwitchSection(const MCSection *Section);
45 virtual void EmitLabel(MCSymbol *Symbol);
47 virtual void EmitAssemblerFlag(AssemblerFlag Flag);
49 virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
51 virtual void EmitSymbolAttribute(MCSymbol *Symbol, SymbolAttr Attribute);
53 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
55 virtual void EmitCommonSymbol(MCSymbol *Symbol, unsigned Size,
56 unsigned ByteAlignment);
58 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
59 unsigned Size = 0, unsigned ByteAlignment = 0);
61 virtual void EmitBytes(StringRef Data);
63 virtual void EmitValue(const MCExpr *Value, unsigned Size);
64 virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue);
66 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
67 unsigned ValueSize = 1,
68 unsigned MaxBytesToEmit = 0);
70 virtual void EmitValueToOffset(const MCExpr *Offset,
71 unsigned char Value = 0);
73 virtual void EmitInstruction(const MCInst &Inst);
75 virtual void Finish();
80 } // end anonymous namespace.
82 static inline int64_t truncateToSize(int64_t Value, unsigned Bytes) {
83 assert(Bytes && "Invalid size!");
84 return Value & ((uint64_t) (int64_t) -1 >> (64 - Bytes * 8));
87 static inline const MCExpr *truncateToSize(const MCExpr *Value,
89 // FIXME: Do we really need this routine?
93 void MCAsmStreamer::SwitchSection(const MCSection *Section) {
94 assert(Section && "Cannot switch to a null section!");
95 if (Section != CurSection) {
97 Section->PrintSwitchToSection(MAI, OS);
101 void MCAsmStreamer::EmitLabel(MCSymbol *Symbol) {
102 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
103 assert(CurSection && "Cannot emit before setting section!");
105 OS << *Symbol << ":\n";
106 Symbol->setSection(*CurSection);
109 void MCAsmStreamer::EmitAssemblerFlag(AssemblerFlag Flag) {
111 default: assert(0 && "Invalid flag!");
112 case SubsectionsViaSymbols: OS << ".subsections_via_symbols"; break;
117 void MCAsmStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
118 // Only absolute symbols can be redefined.
119 assert((Symbol->isUndefined() || Symbol->isAbsolute()) &&
120 "Cannot define a symbol twice!");
122 OS << *Symbol << " = " << *Value << '\n';
124 // FIXME: Lift context changes into super class.
125 // FIXME: Set associated section.
126 Symbol->setValue(Value);
129 void MCAsmStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
130 SymbolAttr Attribute) {
132 case Global: OS << ".globl"; break;
133 case Hidden: OS << ".hidden"; break;
134 case IndirectSymbol: OS << ".indirect_symbol"; break;
135 case Internal: OS << ".internal"; break;
136 case LazyReference: OS << ".lazy_reference"; break;
137 case NoDeadStrip: OS << ".no_dead_strip"; break;
138 case PrivateExtern: OS << ".private_extern"; break;
139 case Protected: OS << ".protected"; break;
140 case Reference: OS << ".reference"; break;
141 case Weak: OS << ".weak"; break;
142 case WeakDefinition: OS << ".weak_definition"; break;
143 case WeakReference: OS << ".weak_reference"; break;
146 OS << ' ' << *Symbol << '\n';
149 void MCAsmStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
150 OS << ".desc" << ' ' << *Symbol << ',' << DescValue << '\n';
153 void MCAsmStreamer::EmitCommonSymbol(MCSymbol *Symbol, unsigned Size,
154 unsigned ByteAlignment) {
155 OS << MAI.getCOMMDirective() << *Symbol << ',' << Size;
156 if (ByteAlignment != 0 && MAI.getCOMMDirectiveTakesAlignment()) {
157 if (MAI.getAlignmentIsInBytes())
158 OS << ',' << ByteAlignment;
160 OS << ',' << Log2_32(ByteAlignment);
165 void MCAsmStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
166 unsigned Size, unsigned ByteAlignment) {
167 // Note: a .zerofill directive does not switch sections.
170 // This is a mach-o specific directive.
171 const MCSectionMachO *MOSection = ((const MCSectionMachO*)Section);
172 OS << MOSection->getSegmentName() << "," << MOSection->getSectionName();
174 if (Symbol != NULL) {
175 OS << ',' << *Symbol << ',' << Size;
176 if (ByteAlignment != 0)
177 OS << ',' << Log2_32(ByteAlignment);
182 void MCAsmStreamer::EmitBytes(StringRef Data) {
183 assert(CurSection && "Cannot emit contents before setting section!");
184 for (unsigned i = 0, e = Data.size(); i != e; ++i)
185 OS << ".byte " << (unsigned) (unsigned char) Data[i] << '\n';
188 void MCAsmStreamer::EmitValue(const MCExpr *Value, unsigned Size) {
189 assert(CurSection && "Cannot emit contents before setting section!");
190 // Need target hooks to know how to print this.
193 llvm_unreachable("Invalid size for machine code value!");
194 case 1: OS << ".byte"; break;
195 case 2: OS << ".short"; break;
196 case 4: OS << ".long"; break;
197 case 8: OS << ".quad"; break;
200 OS << ' ' << *truncateToSize(Value, Size) << '\n';
203 /// EmitFill - Emit NumBytes bytes worth of the value specified by
204 /// FillValue. This implements directives such as '.space'.
205 void MCAsmStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue) {
206 if (NumBytes == 0) return;
208 if (const char *ZeroDirective = MAI.getZeroDirective()) {
209 OS << ZeroDirective << NumBytes;
211 OS << ',' << (int)FillValue;
214 // Emit a byte at a time.
215 MCStreamer::EmitFill(NumBytes, FillValue);
219 void MCAsmStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
221 unsigned MaxBytesToEmit) {
222 // Some assemblers don't support non-power of two alignments, so we always
223 // emit alignments as a power of two if possible.
224 if (isPowerOf2_32(ByteAlignment)) {
226 default: llvm_unreachable("Invalid size for machine code value!");
227 case 1: OS << MAI.getAlignDirective(); break;
228 // FIXME: use MAI for this!
229 case 2: OS << ".p2alignw "; break;
230 case 4: OS << ".p2alignl "; break;
231 case 8: llvm_unreachable("Unsupported alignment size!");
234 if (MAI.getAlignmentIsInBytes())
237 OS << Log2_32(ByteAlignment);
239 if (Value || MaxBytesToEmit) {
241 OS.write_hex(truncateToSize(Value, ValueSize));
244 OS << ", " << MaxBytesToEmit;
250 // Non-power of two alignment. This is not widely supported by assemblers.
251 // FIXME: Parameterize this based on MAI.
253 default: llvm_unreachable("Invalid size for machine code value!");
254 case 1: OS << ".balign"; break;
255 case 2: OS << ".balignw"; break;
256 case 4: OS << ".balignl"; break;
257 case 8: llvm_unreachable("Unsupported alignment size!");
260 OS << ' ' << ByteAlignment;
261 OS << ", " << truncateToSize(Value, ValueSize);
263 OS << ", " << MaxBytesToEmit;
267 void MCAsmStreamer::EmitValueToOffset(const MCExpr *Offset,
268 unsigned char Value) {
269 // FIXME: Verify that Offset is associated with the current section.
270 OS << ".org " << *Offset << ", " << (unsigned) Value << '\n';
273 void MCAsmStreamer::EmitInstruction(const MCInst &Inst) {
274 assert(CurSection && "Cannot emit contents before setting section!");
276 // If we have an AsmPrinter, use that to print.
278 InstPrinter->printInst(&Inst);
281 // Show the encoding if we have a code emitter.
283 SmallString<256> Code;
284 raw_svector_ostream VecOS(Code);
285 Emitter->EncodeInstruction(Inst, VecOS);
289 OS << " # encoding: [";
290 for (unsigned i = 0, e = Code.size(); i != e; ++i) {
293 OS << format("%#04x", uint8_t(Code[i]));
301 // Otherwise fall back to a structural printing for now. Eventually we should
302 // always have access to the target specific printer.
303 Inst.print(OS, &MAI);
307 void MCAsmStreamer::Finish() {
311 MCStreamer *llvm::createAsmStreamer(MCContext &Context, raw_ostream &OS,
312 const MCAsmInfo &MAI, MCInstPrinter *IP,
314 return new MCAsmStreamer(Context, OS, MAI, IP, CE);