1 //===- lib/MC/MCPureStreamer.cpp - MC "Pure" Object 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 #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/MCObjectFileInfo.h"
16 #include "llvm/MC/MCObjectStreamer.h"
17 #include "llvm/MC/MCSymbol.h"
18 #include "llvm/Support/ErrorHandling.h"
19
20 using namespace llvm;
21
22 namespace {
23
24 class MCPureStreamer : public MCObjectStreamer {
25 private:
26 virtual void EmitInstToFragment(const MCInst &Inst);
27 virtual void EmitInstToData(const MCInst &Inst);
28
29 public:
MCPureStreamer(MCContext & Context,MCAsmBackend & TAB,raw_ostream & OS,MCCodeEmitter * Emitter)30 MCPureStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &OS,
31 MCCodeEmitter *Emitter)
32 : MCObjectStreamer(SK_PureStreamer, Context, TAB, OS, Emitter) {}
33
34 /// @name MCStreamer Interface
35 /// @{
36
37 virtual void InitSections();
38 virtual void InitToTextSection();
39 virtual void EmitLabel(MCSymbol *Symbol);
40 virtual void EmitDebugLabel(MCSymbol *Symbol);
41 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
42 uint64_t Size = 0, unsigned ByteAlignment = 0);
43 virtual void EmitBytes(StringRef Data);
44 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
45 unsigned ValueSize = 1,
46 unsigned MaxBytesToEmit = 0);
47 virtual void EmitCodeAlignment(unsigned ByteAlignment,
48 unsigned MaxBytesToEmit = 0);
49 virtual bool EmitValueToOffset(const MCExpr *Offset,
50 unsigned char Value = 0);
51 virtual void FinishImpl();
52
53
EmitSymbolAttribute(MCSymbol * Symbol,MCSymbolAttr Attribute)54 virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) {
55 report_fatal_error("unsupported directive in pure streamer");
56 }
EmitAssemblerFlag(MCAssemblerFlag Flag)57 virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) {
58 report_fatal_error("unsupported directive in pure streamer");
59 }
EmitTBSSSymbol(const MCSection * Section,MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment=0)60 virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
61 uint64_t Size, unsigned ByteAlignment = 0) {
62 report_fatal_error("unsupported directive in pure streamer");
63 }
EmitSymbolDesc(MCSymbol * Symbol,unsigned DescValue)64 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
65 report_fatal_error("unsupported directive in pure streamer");
66 }
EmitCommonSymbol(MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)67 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
68 unsigned ByteAlignment) {
69 report_fatal_error("unsupported directive in pure streamer");
70 }
EmitThumbFunc(MCSymbol * Func)71 virtual void EmitThumbFunc(MCSymbol *Func) {
72 report_fatal_error("unsupported directive in pure streamer");
73 }
BeginCOFFSymbolDef(const MCSymbol * Symbol)74 virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) {
75 report_fatal_error("unsupported directive in pure streamer");
76 }
EmitCOFFSymbolStorageClass(int StorageClass)77 virtual void EmitCOFFSymbolStorageClass(int StorageClass) {
78 report_fatal_error("unsupported directive in pure streamer");
79 }
EmitCOFFSymbolType(int Type)80 virtual void EmitCOFFSymbolType(int Type) {
81 report_fatal_error("unsupported directive in pure streamer");
82 }
EndCOFFSymbolDef()83 virtual void EndCOFFSymbolDef() {
84 report_fatal_error("unsupported directive in pure streamer");
85 }
EmitELFSize(MCSymbol * Symbol,const MCExpr * Value)86 virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
87 report_fatal_error("unsupported directive in pure streamer");
88 }
EmitLocalCommonSymbol(MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)89 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
90 unsigned ByteAlignment) {
91 report_fatal_error("unsupported directive in pure streamer");
92 }
EmitFileDirective(StringRef Filename)93 virtual void EmitFileDirective(StringRef Filename) {
94 report_fatal_error("unsupported directive in pure streamer");
95 }
EmitDwarfFileDirective(unsigned FileNo,StringRef Directory,StringRef Filename,unsigned CUID=0)96 virtual bool EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
97 StringRef Filename, unsigned CUID = 0) {
98 report_fatal_error("unsupported directive in pure streamer");
99 }
100
101 /// @}
102
classof(const MCStreamer * S)103 static bool classof(const MCStreamer *S) {
104 return S->getKind() == SK_PureStreamer;
105 }
106 };
107
108 } // end anonymous namespace.
109
InitSections()110 void MCPureStreamer::InitSections() {
111 InitToTextSection();
112 }
113
InitToTextSection()114 void MCPureStreamer::InitToTextSection() {
115 SwitchSection(getContext().getObjectFileInfo()->getTextSection());
116 }
117
EmitLabel(MCSymbol * Symbol)118 void MCPureStreamer::EmitLabel(MCSymbol *Symbol) {
119 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
120 assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
121 assert(getCurrentSection().first && "Cannot emit before setting section!");
122
123 Symbol->setSection(*getCurrentSection().first);
124
125 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
126
127 // We have to create a new fragment if this is an atom defining symbol,
128 // fragments cannot span atoms.
129 if (getAssembler().isSymbolLinkerVisible(SD.getSymbol()))
130 insert(new MCDataFragment());
131
132 // FIXME: This is wasteful, we don't necessarily need to create a data
133 // fragment. Instead, we should mark the symbol as pointing into the data
134 // fragment if it exists, otherwise we should just queue the label and set its
135 // fragment pointer when we emit the next fragment.
136 MCDataFragment *F = getOrCreateDataFragment();
137 assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
138 SD.setFragment(F);
139 SD.setOffset(F->getContents().size());
140 }
141
142
EmitDebugLabel(MCSymbol * Symbol)143 void MCPureStreamer::EmitDebugLabel(MCSymbol *Symbol) {
144 EmitLabel(Symbol);
145 }
146
EmitZerofill(const MCSection * Section,MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)147 void MCPureStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
148 uint64_t Size, unsigned ByteAlignment) {
149 report_fatal_error("not yet implemented in pure streamer");
150 }
151
EmitBytes(StringRef Data)152 void MCPureStreamer::EmitBytes(StringRef Data) {
153 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
154 // MCObjectStreamer.
155 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
156 }
157
EmitValueToAlignment(unsigned ByteAlignment,int64_t Value,unsigned ValueSize,unsigned MaxBytesToEmit)158 void MCPureStreamer::EmitValueToAlignment(unsigned ByteAlignment,
159 int64_t Value, unsigned ValueSize,
160 unsigned MaxBytesToEmit) {
161 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
162 // MCObjectStreamer.
163 if (MaxBytesToEmit == 0)
164 MaxBytesToEmit = ByteAlignment;
165 insert(new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit));
166
167 // Update the maximum alignment on the current section if necessary.
168 if (ByteAlignment > getCurrentSectionData()->getAlignment())
169 getCurrentSectionData()->setAlignment(ByteAlignment);
170 }
171
EmitCodeAlignment(unsigned ByteAlignment,unsigned MaxBytesToEmit)172 void MCPureStreamer::EmitCodeAlignment(unsigned ByteAlignment,
173 unsigned MaxBytesToEmit) {
174 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
175 // MCObjectStreamer.
176 if (MaxBytesToEmit == 0)
177 MaxBytesToEmit = ByteAlignment;
178 MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit);
179 insert(F);
180 F->setEmitNops(true);
181
182 // Update the maximum alignment on the current section if necessary.
183 if (ByteAlignment > getCurrentSectionData()->getAlignment())
184 getCurrentSectionData()->setAlignment(ByteAlignment);
185 }
186
EmitValueToOffset(const MCExpr * Offset,unsigned char Value)187 bool MCPureStreamer::EmitValueToOffset(const MCExpr *Offset,
188 unsigned char Value) {
189 insert(new MCOrgFragment(*Offset, Value));
190 return false;
191 }
192
EmitInstToFragment(const MCInst & Inst)193 void MCPureStreamer::EmitInstToFragment(const MCInst &Inst) {
194 MCRelaxableFragment *IF = new MCRelaxableFragment(Inst);
195 insert(IF);
196
197 // Add the fixups and data.
198 //
199 // FIXME: Revisit this design decision when relaxation is done, we may be
200 // able to get away with not storing any extra data in the MCInst.
201 SmallVector<MCFixup, 4> Fixups;
202 SmallString<256> Code;
203 raw_svector_ostream VecOS(Code);
204 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
205 VecOS.flush();
206
207 IF->getContents() = Code;
208 IF->getFixups() = Fixups;
209 }
210
EmitInstToData(const MCInst & Inst)211 void MCPureStreamer::EmitInstToData(const MCInst &Inst) {
212 MCDataFragment *DF = getOrCreateDataFragment();
213
214 SmallVector<MCFixup, 4> Fixups;
215 SmallString<256> Code;
216 raw_svector_ostream VecOS(Code);
217 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
218 VecOS.flush();
219
220 // Add the fixups and data.
221 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
222 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
223 DF->getFixups().push_back(Fixups[i]);
224 }
225 DF->getContents().append(Code.begin(), Code.end());
226 }
227
FinishImpl()228 void MCPureStreamer::FinishImpl() {
229 // FIXME: Handle DWARF tables?
230
231 this->MCObjectStreamer::FinishImpl();
232 }
233
createPureStreamer(MCContext & Context,MCAsmBackend & MAB,raw_ostream & OS,MCCodeEmitter * CE)234 MCStreamer *llvm::createPureStreamer(MCContext &Context, MCAsmBackend &MAB,
235 raw_ostream &OS, MCCodeEmitter *CE) {
236 return new MCPureStreamer(Context, MAB, OS, CE);
237 }
238