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(const StringRef &Data);
63 virtual void EmitValue(const MCExpr *Value, unsigned Size);
65 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
66 unsigned ValueSize = 1,
67 unsigned MaxBytesToEmit = 0);
69 virtual void EmitValueToOffset(const MCExpr *Offset,
70 unsigned char Value = 0);
72 virtual void EmitInstruction(const MCInst &Inst);
74 virtual void Finish();
79 } // end anonymous namespace.
81 static inline int64_t truncateToSize(int64_t Value, unsigned Bytes) {
82 assert(Bytes && "Invalid size!");
83 return Value & ((uint64_t) (int64_t) -1 >> (64 - Bytes * 8));
86 static inline const MCExpr *truncateToSize(const MCExpr *Value,
88 // FIXME: Do we really need this routine?
92 void MCAsmStreamer::SwitchSection(const MCSection *Section) {
93 assert(Section && "Cannot switch to a null section!");
94 if (Section != CurSection) {
96 Section->PrintSwitchToSection(MAI, OS);
100 void MCAsmStreamer::EmitLabel(MCSymbol *Symbol) {
101 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
102 assert(CurSection && "Cannot emit before setting section!");
104 Symbol->print(OS, &MAI);
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 Symbol->print(OS, &MAI);
124 Value->print(OS, &MAI);
127 // FIXME: Lift context changes into super class.
128 Symbol->setValue(Value);
131 void MCAsmStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
132 SymbolAttr Attribute) {
134 case Global: OS << ".globl"; break;
135 case Hidden: OS << ".hidden"; break;
136 case IndirectSymbol: OS << ".indirect_symbol"; break;
137 case Internal: OS << ".internal"; break;
138 case LazyReference: OS << ".lazy_reference"; break;
139 case NoDeadStrip: OS << ".no_dead_strip"; break;
140 case PrivateExtern: OS << ".private_extern"; break;
141 case Protected: OS << ".protected"; break;
142 case Reference: OS << ".reference"; break;
143 case Weak: OS << ".weak"; break;
144 case WeakDefinition: OS << ".weak_definition"; break;
145 case WeakReference: OS << ".weak_reference"; break;
149 Symbol->print(OS, &MAI);
153 void MCAsmStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
154 OS << ".desc" << ' ';
155 Symbol->print(OS, &MAI);
156 OS << ',' << DescValue << '\n';
159 void MCAsmStreamer::EmitCommonSymbol(MCSymbol *Symbol, unsigned Size,
160 unsigned ByteAlignment) {
162 Symbol->print(OS, &MAI);
164 if (ByteAlignment != 0)
165 OS << ',' << Log2_32(ByteAlignment);
169 void MCAsmStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
170 unsigned Size, unsigned ByteAlignment) {
171 // Note: a .zerofill directive does not switch sections.
174 // This is a mach-o specific directive.
175 const MCSectionMachO *MOSection = ((const MCSectionMachO*)Section);
176 OS << MOSection->getSegmentName() << "," << MOSection->getSectionName();
178 if (Symbol != NULL) {
180 Symbol->print(OS, &MAI);
182 if (ByteAlignment != 0)
183 OS << ',' << Log2_32(ByteAlignment);
188 void MCAsmStreamer::EmitBytes(const StringRef &Data) {
189 assert(CurSection && "Cannot emit contents before setting section!");
190 for (unsigned i = 0, e = Data.size(); i != e; ++i)
191 OS << ".byte " << (unsigned) (unsigned char) Data[i] << '\n';
194 void MCAsmStreamer::EmitValue(const MCExpr *Value, unsigned Size) {
195 assert(CurSection && "Cannot emit contents before setting section!");
196 // Need target hooks to know how to print this.
199 llvm_unreachable("Invalid size for machine code value!");
200 case 1: OS << ".byte"; break;
201 case 2: OS << ".short"; break;
202 case 4: OS << ".long"; break;
203 case 8: OS << ".quad"; break;
207 truncateToSize(Value, Size)->print(OS, &MAI);
211 void MCAsmStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
213 unsigned MaxBytesToEmit) {
214 // Some assemblers don't support non-power of two alignments, so we always
215 // emit alignments as a power of two if possible.
216 if (isPowerOf2_32(ByteAlignment)) {
218 default: llvm_unreachable("Invalid size for machine code value!");
219 case 1: OS << MAI.getAlignDirective(); break;
220 // FIXME: use MAI for this!
221 case 2: OS << ".p2alignw "; break;
222 case 4: OS << ".p2alignl "; break;
223 case 8: llvm_unreachable("Unsupported alignment size!");
226 if (MAI.getAlignmentIsInBytes())
229 OS << Log2_32(ByteAlignment);
231 if (Value || MaxBytesToEmit) {
233 OS.write_hex(truncateToSize(Value, ValueSize));
236 OS << ", " << MaxBytesToEmit;
242 // Non-power of two alignment. This is not widely supported by assemblers.
243 // FIXME: Parameterize this based on MAI.
245 default: llvm_unreachable("Invalid size for machine code value!");
246 case 1: OS << ".balign"; break;
247 case 2: OS << ".balignw"; break;
248 case 4: OS << ".balignl"; break;
249 case 8: llvm_unreachable("Unsupported alignment size!");
252 OS << ' ' << ByteAlignment;
253 OS << ", " << truncateToSize(Value, ValueSize);
255 OS << ", " << MaxBytesToEmit;
259 void MCAsmStreamer::EmitValueToOffset(const MCExpr *Offset,
260 unsigned char Value) {
261 // FIXME: Verify that Offset is associated with the current section.
263 Offset->print(OS, &MAI);
264 OS << ", " << (unsigned) Value << '\n';
267 void MCAsmStreamer::EmitInstruction(const MCInst &Inst) {
268 assert(CurSection && "Cannot emit contents before setting section!");
270 // If we have an AsmPrinter, use that to print.
272 InstPrinter->printInst(&Inst);
275 // Show the encoding if we have a code emitter.
277 SmallString<256> Code;
278 raw_svector_ostream VecOS(Code);
279 Emitter->EncodeInstruction(Inst, VecOS);
283 OS << " # encoding: [";
284 for (unsigned i = 0, e = Code.size(); i != e; ++i) {
287 OS << format("%#04x", uint8_t(Code[i]));
295 // Otherwise fall back to a structural printing for now. Eventually we should
296 // always have access to the target specific printer.
297 Inst.print(OS, &MAI);
301 void MCAsmStreamer::Finish() {
305 MCStreamer *llvm::createAsmStreamer(MCContext &Context, raw_ostream &OS,
306 const MCAsmInfo &MAI, MCInstPrinter *IP,
308 return new MCAsmStreamer(Context, OS, MAI, IP, CE);