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/MCObjectStreamer.h"
16 // FIXME: Remove this.
17 #include "llvm/MC/MCSectionMachO.h"
18 #include "llvm/MC/MCSymbol.h"
19 #include "llvm/Support/ErrorHandling.h"
20
21 using namespace llvm;
22
23 namespace {
24
25 class MCPureStreamer : public MCObjectStreamer {
26 private:
27 virtual void EmitInstToFragment(const MCInst &Inst);
28 virtual void EmitInstToData(const MCInst &Inst);
29
30 public:
MCPureStreamer(MCContext & Context,MCAsmBackend & TAB,raw_ostream & OS,MCCodeEmitter * Emitter)31 MCPureStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &OS,
32 MCCodeEmitter *Emitter)
33 : MCObjectStreamer(SK_PureStreamer, Context, TAB, OS, Emitter) {}
34
35 /// @name MCStreamer Interface
36 /// @{
37
38 virtual void InitSections();
39 virtual void InitToTextSection();
40 virtual void EmitLabel(MCSymbol *Symbol);
41 virtual void EmitDebugLabel(MCSymbol *Symbol);
42 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
43 uint64_t Size = 0, unsigned ByteAlignment = 0);
44 virtual void EmitBytes(StringRef Data, unsigned AddrSpace);
45 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
46 unsigned ValueSize = 1,
47 unsigned MaxBytesToEmit = 0);
48 virtual void EmitCodeAlignment(unsigned ByteAlignment,
49 unsigned MaxBytesToEmit = 0);
50 virtual bool EmitValueToOffset(const MCExpr *Offset,
51 unsigned char Value = 0);
52 virtual void FinishImpl();
53
54
EmitSymbolAttribute(MCSymbol * Symbol,MCSymbolAttr Attribute)55 virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) {
56 report_fatal_error("unsupported directive in pure streamer");
57 }
EmitAssemblerFlag(MCAssemblerFlag Flag)58 virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) {
59 report_fatal_error("unsupported directive in pure streamer");
60 }
EmitTBSSSymbol(const MCSection * Section,MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment=0)61 virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
62 uint64_t Size, unsigned ByteAlignment = 0) {
63 report_fatal_error("unsupported directive in pure streamer");
64 }
EmitSymbolDesc(MCSymbol * Symbol,unsigned DescValue)65 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
66 report_fatal_error("unsupported directive in pure streamer");
67 }
EmitCommonSymbol(MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)68 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
69 unsigned ByteAlignment) {
70 report_fatal_error("unsupported directive in pure streamer");
71 }
EmitThumbFunc(MCSymbol * Func)72 virtual void EmitThumbFunc(MCSymbol *Func) {
73 report_fatal_error("unsupported directive in pure streamer");
74 }
BeginCOFFSymbolDef(const MCSymbol * Symbol)75 virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) {
76 report_fatal_error("unsupported directive in pure streamer");
77 }
EmitCOFFSymbolStorageClass(int StorageClass)78 virtual void EmitCOFFSymbolStorageClass(int StorageClass) {
79 report_fatal_error("unsupported directive in pure streamer");
80 }
EmitCOFFSymbolType(int Type)81 virtual void EmitCOFFSymbolType(int Type) {
82 report_fatal_error("unsupported directive in pure streamer");
83 }
EndCOFFSymbolDef()84 virtual void EndCOFFSymbolDef() {
85 report_fatal_error("unsupported directive in pure streamer");
86 }
EmitELFSize(MCSymbol * Symbol,const MCExpr * Value)87 virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
88 report_fatal_error("unsupported directive in pure streamer");
89 }
EmitLocalCommonSymbol(MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)90 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
91 unsigned ByteAlignment) {
92 report_fatal_error("unsupported directive in pure streamer");
93 }
EmitFileDirective(StringRef Filename)94 virtual void EmitFileDirective(StringRef Filename) {
95 report_fatal_error("unsupported directive in pure streamer");
96 }
EmitDwarfFileDirective(unsigned FileNo,StringRef Directory,StringRef Filename,unsigned CUID=0)97 virtual bool EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
98 StringRef Filename, unsigned CUID = 0) {
99 report_fatal_error("unsupported directive in pure streamer");
100 }
101
102 /// @}
103
classof(const MCStreamer * S)104 static bool classof(const MCStreamer *S) {
105 return S->getKind() == SK_PureStreamer;
106 }
107 };
108
109 } // end anonymous namespace.
110
InitSections()111 void MCPureStreamer::InitSections() {
112 InitToTextSection();
113 }
114
InitToTextSection()115 void MCPureStreamer::InitToTextSection() {
116 // FIMXE: To what!?
117 SwitchSection(getContext().getMachOSection("__TEXT", "__text",
118 MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
119 0, SectionKind::getText()));
120 }
121
EmitLabel(MCSymbol * Symbol)122 void MCPureStreamer::EmitLabel(MCSymbol *Symbol) {
123 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
124 assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
125 assert(getCurrentSection() && "Cannot emit before setting section!");
126
127 Symbol->setSection(*getCurrentSection());
128
129 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
130
131 // We have to create a new fragment if this is an atom defining symbol,
132 // fragments cannot span atoms.
133 if (getAssembler().isSymbolLinkerVisible(SD.getSymbol()))
134 new MCDataFragment(getCurrentSectionData());
135
136 // FIXME: This is wasteful, we don't necessarily need to create a data
137 // fragment. Instead, we should mark the symbol as pointing into the data
138 // fragment if it exists, otherwise we should just queue the label and set its
139 // fragment pointer when we emit the next fragment.
140 MCDataFragment *F = getOrCreateDataFragment();
141 assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
142 SD.setFragment(F);
143 SD.setOffset(F->getContents().size());
144 }
145
146
EmitDebugLabel(MCSymbol * Symbol)147 void MCPureStreamer::EmitDebugLabel(MCSymbol *Symbol) {
148 EmitLabel(Symbol);
149 }
150
EmitZerofill(const MCSection * Section,MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)151 void MCPureStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
152 uint64_t Size, unsigned ByteAlignment) {
153 report_fatal_error("not yet implemented in pure streamer");
154 }
155
EmitBytes(StringRef Data,unsigned AddrSpace)156 void MCPureStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
157 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
158 // MCObjectStreamer.
159 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
160 }
161
EmitValueToAlignment(unsigned ByteAlignment,int64_t Value,unsigned ValueSize,unsigned MaxBytesToEmit)162 void MCPureStreamer::EmitValueToAlignment(unsigned ByteAlignment,
163 int64_t Value, unsigned ValueSize,
164 unsigned MaxBytesToEmit) {
165 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
166 // MCObjectStreamer.
167 if (MaxBytesToEmit == 0)
168 MaxBytesToEmit = ByteAlignment;
169 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
170 getCurrentSectionData());
171
172 // Update the maximum alignment on the current section if necessary.
173 if (ByteAlignment > getCurrentSectionData()->getAlignment())
174 getCurrentSectionData()->setAlignment(ByteAlignment);
175 }
176
EmitCodeAlignment(unsigned ByteAlignment,unsigned MaxBytesToEmit)177 void MCPureStreamer::EmitCodeAlignment(unsigned ByteAlignment,
178 unsigned MaxBytesToEmit) {
179 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
180 // MCObjectStreamer.
181 if (MaxBytesToEmit == 0)
182 MaxBytesToEmit = ByteAlignment;
183 MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit,
184 getCurrentSectionData());
185 F->setEmitNops(true);
186
187 // Update the maximum alignment on the current section if necessary.
188 if (ByteAlignment > getCurrentSectionData()->getAlignment())
189 getCurrentSectionData()->setAlignment(ByteAlignment);
190 }
191
EmitValueToOffset(const MCExpr * Offset,unsigned char Value)192 bool MCPureStreamer::EmitValueToOffset(const MCExpr *Offset,
193 unsigned char Value) {
194 new MCOrgFragment(*Offset, Value, getCurrentSectionData());
195 return false;
196 }
197
EmitInstToFragment(const MCInst & Inst)198 void MCPureStreamer::EmitInstToFragment(const MCInst &Inst) {
199 MCRelaxableFragment *IF =
200 new MCRelaxableFragment(Inst, getCurrentSectionData());
201
202 // Add the fixups and data.
203 //
204 // FIXME: Revisit this design decision when relaxation is done, we may be
205 // able to get away with not storing any extra data in the MCInst.
206 SmallVector<MCFixup, 4> Fixups;
207 SmallString<256> Code;
208 raw_svector_ostream VecOS(Code);
209 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
210 VecOS.flush();
211
212 IF->getContents() = Code;
213 IF->getFixups() = Fixups;
214 }
215
EmitInstToData(const MCInst & Inst)216 void MCPureStreamer::EmitInstToData(const MCInst &Inst) {
217 MCDataFragment *DF = getOrCreateDataFragment();
218
219 SmallVector<MCFixup, 4> Fixups;
220 SmallString<256> Code;
221 raw_svector_ostream VecOS(Code);
222 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
223 VecOS.flush();
224
225 // Add the fixups and data.
226 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
227 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
228 DF->getFixups().push_back(Fixups[i]);
229 }
230 DF->getContents().append(Code.begin(), Code.end());
231 }
232
FinishImpl()233 void MCPureStreamer::FinishImpl() {
234 // FIXME: Handle DWARF tables?
235
236 this->MCObjectStreamer::FinishImpl();
237 }
238
createPureStreamer(MCContext & Context,MCAsmBackend & MAB,raw_ostream & OS,MCCodeEmitter * CE)239 MCStreamer *llvm::createPureStreamer(MCContext &Context, MCAsmBackend &MAB,
240 raw_ostream &OS, MCCodeEmitter *CE) {
241 return new MCPureStreamer(Context, MAB, OS, CE);
242 }
243