1 //===- lib/MC/MCPureStreamer.cpp - MC "Pure" Object 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/MC/MCAssembler.h"
12 #include "llvm/MC/MCCodeEmitter.h"
13 #include "llvm/MC/MCContext.h"
14 #include "llvm/MC/MCExpr.h"
15 #include "llvm/MC/MCObjectStreamer.h"
16 // FIXME: Remove this.
17 #include "llvm/MC/MCSectionMachO.h"
18 #include "llvm/MC/MCSymbol.h"
19 #include "llvm/Support/ErrorHandling.h"
25 class MCPureStreamer : public MCObjectStreamer {
27 virtual void EmitInstToFragment(const MCInst &Inst);
28 virtual void EmitInstToData(const MCInst &Inst);
31 MCPureStreamer(MCContext &Context, MCAsmBackend &TAB,
32 raw_ostream &OS, MCCodeEmitter *Emitter)
33 : MCObjectStreamer(Context, TAB, OS, Emitter) {}
35 /// @name MCStreamer Interface
38 virtual void InitSections();
39 virtual void EmitLabel(MCSymbol *Symbol);
40 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
41 uint64_t Size = 0, unsigned ByteAlignment = 0);
42 virtual void EmitBytes(StringRef Data, unsigned AddrSpace);
43 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
44 unsigned ValueSize = 1,
45 unsigned MaxBytesToEmit = 0);
46 virtual void EmitCodeAlignment(unsigned ByteAlignment,
47 unsigned MaxBytesToEmit = 0);
48 virtual bool EmitValueToOffset(const MCExpr *Offset,
49 unsigned char Value = 0);
50 virtual void FinishImpl();
53 virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) {
54 report_fatal_error("unsupported directive in pure streamer");
56 virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) {
57 report_fatal_error("unsupported directive in pure streamer");
59 virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
60 uint64_t Size, unsigned ByteAlignment = 0) {
61 report_fatal_error("unsupported directive in pure streamer");
63 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
64 report_fatal_error("unsupported directive in pure streamer");
66 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
67 unsigned ByteAlignment) {
68 report_fatal_error("unsupported directive in pure streamer");
70 virtual void EmitThumbFunc(MCSymbol *Func) {
71 report_fatal_error("unsupported directive in pure streamer");
73 virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) {
74 report_fatal_error("unsupported directive in pure streamer");
76 virtual void EmitCOFFSymbolStorageClass(int StorageClass) {
77 report_fatal_error("unsupported directive in pure streamer");
79 virtual void EmitCOFFSymbolType(int Type) {
80 report_fatal_error("unsupported directive in pure streamer");
82 virtual void EndCOFFSymbolDef() {
83 report_fatal_error("unsupported directive in pure streamer");
85 virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
86 report_fatal_error("unsupported directive in pure streamer");
88 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
89 unsigned ByteAlignment) {
90 report_fatal_error("unsupported directive in pure streamer");
92 virtual void EmitFileDirective(StringRef Filename) {
93 report_fatal_error("unsupported directive in pure streamer");
95 virtual bool EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
97 report_fatal_error("unsupported directive in pure streamer");
103 } // end anonymous namespace.
105 void MCPureStreamer::InitSections() {
107 SwitchSection(getContext().getMachOSection("__TEXT", "__text",
108 MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
109 0, SectionKind::getText()));
113 void MCPureStreamer::EmitLabel(MCSymbol *Symbol) {
114 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
115 assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
116 assert(getCurrentSection() && "Cannot emit before setting section!");
118 Symbol->setSection(*getCurrentSection());
120 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
122 // We have to create a new fragment if this is an atom defining symbol,
123 // fragments cannot span atoms.
124 if (getAssembler().isSymbolLinkerVisible(SD.getSymbol()))
125 new MCDataFragment(getCurrentSectionData());
127 // FIXME: This is wasteful, we don't necessarily need to create a data
128 // fragment. Instead, we should mark the symbol as pointing into the data
129 // fragment if it exists, otherwise we should just queue the label and set its
130 // fragment pointer when we emit the next fragment.
131 MCDataFragment *F = getOrCreateDataFragment();
132 assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
134 SD.setOffset(F->getContents().size());
137 void MCPureStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
138 uint64_t Size, unsigned ByteAlignment) {
139 report_fatal_error("not yet implemented in pure streamer");
142 void MCPureStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
143 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
145 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
148 void MCPureStreamer::EmitValueToAlignment(unsigned ByteAlignment,
149 int64_t Value, unsigned ValueSize,
150 unsigned MaxBytesToEmit) {
151 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
153 if (MaxBytesToEmit == 0)
154 MaxBytesToEmit = ByteAlignment;
155 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
156 getCurrentSectionData());
158 // Update the maximum alignment on the current section if necessary.
159 if (ByteAlignment > getCurrentSectionData()->getAlignment())
160 getCurrentSectionData()->setAlignment(ByteAlignment);
163 void MCPureStreamer::EmitCodeAlignment(unsigned ByteAlignment,
164 unsigned MaxBytesToEmit) {
165 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
167 if (MaxBytesToEmit == 0)
168 MaxBytesToEmit = ByteAlignment;
169 MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit,
170 getCurrentSectionData());
171 F->setEmitNops(true);
173 // Update the maximum alignment on the current section if necessary.
174 if (ByteAlignment > getCurrentSectionData()->getAlignment())
175 getCurrentSectionData()->setAlignment(ByteAlignment);
178 bool MCPureStreamer::EmitValueToOffset(const MCExpr *Offset,
179 unsigned char Value) {
180 new MCOrgFragment(*Offset, Value, getCurrentSectionData());
184 void MCPureStreamer::EmitInstToFragment(const MCInst &Inst) {
185 MCInstFragment *IF = new MCInstFragment(Inst, getCurrentSectionData());
187 // Add the fixups and data.
189 // FIXME: Revisit this design decision when relaxation is done, we may be
190 // able to get away with not storing any extra data in the MCInst.
191 SmallVector<MCFixup, 4> Fixups;
192 SmallString<256> Code;
193 raw_svector_ostream VecOS(Code);
194 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
197 IF->getCode() = Code;
198 IF->getFixups() = Fixups;
201 void MCPureStreamer::EmitInstToData(const MCInst &Inst) {
202 MCDataFragment *DF = getOrCreateDataFragment();
204 SmallVector<MCFixup, 4> Fixups;
205 SmallString<256> Code;
206 raw_svector_ostream VecOS(Code);
207 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
210 // Add the fixups and data.
211 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
212 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
213 DF->addFixup(Fixups[i]);
215 DF->getContents().append(Code.begin(), Code.end());
218 void MCPureStreamer::FinishImpl() {
219 // FIXME: Handle DWARF tables?
221 this->MCObjectStreamer::FinishImpl();
224 MCStreamer *llvm::createPureStreamer(MCContext &Context, MCAsmBackend &MAB,
225 raw_ostream &OS, MCCodeEmitter *CE) {
226 return new MCPureStreamer(Context, MAB, OS, CE);