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,
32 raw_ostream &OS, MCCodeEmitter *Emitter)
33 : MCObjectStreamer(Context, TAB, OS, Emitter) {}
34
35 /// @name MCStreamer Interface
36 /// @{
37
38 virtual void InitSections();
39 virtual void EmitLabel(MCSymbol *Symbol);
40 virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
41 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
42 unsigned Size = 0, unsigned ByteAlignment = 0);
43 virtual void EmitBytes(StringRef Data, unsigned AddrSpace);
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 void EmitValueToOffset(const MCExpr *Offset,
50 unsigned char Value = 0);
51 virtual void Finish();
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 Filename)96 virtual bool EmitDwarfFileDirective(unsigned FileNo, StringRef Filename) {
97 report_fatal_error("unsupported directive in pure streamer");
98 return false;
99 }
100
101 /// @}
102 };
103
104 } // end anonymous namespace.
105
InitSections()106 void MCPureStreamer::InitSections() {
107 // FIMXE: To what!?
108 SwitchSection(getContext().getMachOSection("__TEXT", "__text",
109 MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
110 0, SectionKind::getText()));
111
112 }
113
EmitLabel(MCSymbol * Symbol)114 void MCPureStreamer::EmitLabel(MCSymbol *Symbol) {
115 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
116 assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
117 assert(getCurrentSection() && "Cannot emit before setting section!");
118
119 Symbol->setSection(*getCurrentSection());
120
121 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
122
123 // We have to create a new fragment if this is an atom defining symbol,
124 // fragments cannot span atoms.
125 if (getAssembler().isSymbolLinkerVisible(SD.getSymbol()))
126 new MCDataFragment(getCurrentSectionData());
127
128 // FIXME: This is wasteful, we don't necessarily need to create a data
129 // fragment. Instead, we should mark the symbol as pointing into the data
130 // fragment if it exists, otherwise we should just queue the label and set its
131 // fragment pointer when we emit the next fragment.
132 MCDataFragment *F = getOrCreateDataFragment();
133 assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
134 SD.setFragment(F);
135 SD.setOffset(F->getContents().size());
136 }
137
EmitAssignment(MCSymbol * Symbol,const MCExpr * Value)138 void MCPureStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
139 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
140 // MCObjectStreamer.
141 // FIXME: Lift context changes into super class.
142 getAssembler().getOrCreateSymbolData(*Symbol);
143 Symbol->setVariableValue(AddValueSymbols(Value));
144 }
145
EmitZerofill(const MCSection * Section,MCSymbol * Symbol,unsigned Size,unsigned ByteAlignment)146 void MCPureStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
147 unsigned Size, unsigned ByteAlignment) {
148 report_fatal_error("not yet implemented in pure streamer");
149 }
150
EmitBytes(StringRef Data,unsigned AddrSpace)151 void MCPureStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
152 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
153 // MCObjectStreamer.
154 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
155 }
156
EmitValueToAlignment(unsigned ByteAlignment,int64_t Value,unsigned ValueSize,unsigned MaxBytesToEmit)157 void MCPureStreamer::EmitValueToAlignment(unsigned ByteAlignment,
158 int64_t Value, unsigned ValueSize,
159 unsigned MaxBytesToEmit) {
160 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
161 // MCObjectStreamer.
162 if (MaxBytesToEmit == 0)
163 MaxBytesToEmit = ByteAlignment;
164 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
165 getCurrentSectionData());
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 getCurrentSectionData());
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 void MCPureStreamer::EmitValueToOffset(const MCExpr *Offset,
188 unsigned char Value) {
189 new MCOrgFragment(*Offset, Value, getCurrentSectionData());
190 }
191
EmitInstToFragment(const MCInst & Inst)192 void MCPureStreamer::EmitInstToFragment(const MCInst &Inst) {
193 MCInstFragment *IF = new MCInstFragment(Inst, getCurrentSectionData());
194
195 // Add the fixups and data.
196 //
197 // FIXME: Revisit this design decision when relaxation is done, we may be
198 // able to get away with not storing any extra data in the MCInst.
199 SmallVector<MCFixup, 4> Fixups;
200 SmallString<256> Code;
201 raw_svector_ostream VecOS(Code);
202 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
203 VecOS.flush();
204
205 IF->getCode() = Code;
206 IF->getFixups() = Fixups;
207 }
208
EmitInstToData(const MCInst & Inst)209 void MCPureStreamer::EmitInstToData(const MCInst &Inst) {
210 MCDataFragment *DF = getOrCreateDataFragment();
211
212 SmallVector<MCFixup, 4> Fixups;
213 SmallString<256> Code;
214 raw_svector_ostream VecOS(Code);
215 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
216 VecOS.flush();
217
218 // Add the fixups and data.
219 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
220 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
221 DF->addFixup(Fixups[i]);
222 }
223 DF->getContents().append(Code.begin(), Code.end());
224 }
225
Finish()226 void MCPureStreamer::Finish() {
227 // FIXME: Handle DWARF tables?
228
229 this->MCObjectStreamer::Finish();
230 }
231
createPureStreamer(MCContext & Context,MCAsmBackend & MAB,raw_ostream & OS,MCCodeEmitter * CE)232 MCStreamer *llvm::createPureStreamer(MCContext &Context, MCAsmBackend &MAB,
233 raw_ostream &OS, MCCodeEmitter *CE) {
234 return new MCPureStreamer(Context, MAB, OS, CE);
235 }
236