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,TargetAsmBackend & TAB,raw_ostream & OS,MCCodeEmitter * Emitter)31 MCPureStreamer(MCContext &Context, TargetAsmBackend &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)89 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
90 report_fatal_error("unsupported directive in pure streamer");
91 }
EmitFileDirective(StringRef Filename)92 virtual void EmitFileDirective(StringRef Filename) {
93 report_fatal_error("unsupported directive in pure streamer");
94 }
EmitDwarfFileDirective(unsigned FileNo,StringRef Filename)95 virtual bool EmitDwarfFileDirective(unsigned FileNo, StringRef Filename) {
96 report_fatal_error("unsupported directive in pure streamer");
97 return false;
98 }
99
100 /// @}
101 };
102
103 } // end anonymous namespace.
104
InitSections()105 void MCPureStreamer::InitSections() {
106 // FIMXE: To what!?
107 SwitchSection(getContext().getMachOSection("__TEXT", "__text",
108 MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
109 0, SectionKind::getText()));
110
111 }
112
EmitLabel(MCSymbol * Symbol)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!");
117
118 Symbol->setSection(*getCurrentSection());
119
120 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
121
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());
126
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!");
133 SD.setFragment(F);
134 SD.setOffset(F->getContents().size());
135 }
136
EmitAssignment(MCSymbol * Symbol,const MCExpr * Value)137 void MCPureStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
138 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
139 // MCObjectStreamer.
140 // FIXME: Lift context changes into super class.
141 getAssembler().getOrCreateSymbolData(*Symbol);
142 Symbol->setVariableValue(AddValueSymbols(Value));
143 }
144
EmitZerofill(const MCSection * Section,MCSymbol * Symbol,unsigned Size,unsigned ByteAlignment)145 void MCPureStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
146 unsigned Size, unsigned ByteAlignment) {
147 report_fatal_error("not yet implemented in pure streamer");
148 }
149
EmitBytes(StringRef Data,unsigned AddrSpace)150 void MCPureStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
151 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
152 // MCObjectStreamer.
153 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
154 }
155
EmitValueToAlignment(unsigned ByteAlignment,int64_t Value,unsigned ValueSize,unsigned MaxBytesToEmit)156 void MCPureStreamer::EmitValueToAlignment(unsigned ByteAlignment,
157 int64_t Value, unsigned ValueSize,
158 unsigned MaxBytesToEmit) {
159 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
160 // MCObjectStreamer.
161 if (MaxBytesToEmit == 0)
162 MaxBytesToEmit = ByteAlignment;
163 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
164 getCurrentSectionData());
165
166 // Update the maximum alignment on the current section if necessary.
167 if (ByteAlignment > getCurrentSectionData()->getAlignment())
168 getCurrentSectionData()->setAlignment(ByteAlignment);
169 }
170
EmitCodeAlignment(unsigned ByteAlignment,unsigned MaxBytesToEmit)171 void MCPureStreamer::EmitCodeAlignment(unsigned ByteAlignment,
172 unsigned MaxBytesToEmit) {
173 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
174 // MCObjectStreamer.
175 if (MaxBytesToEmit == 0)
176 MaxBytesToEmit = ByteAlignment;
177 MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit,
178 getCurrentSectionData());
179 F->setEmitNops(true);
180
181 // Update the maximum alignment on the current section if necessary.
182 if (ByteAlignment > getCurrentSectionData()->getAlignment())
183 getCurrentSectionData()->setAlignment(ByteAlignment);
184 }
185
EmitValueToOffset(const MCExpr * Offset,unsigned char Value)186 void MCPureStreamer::EmitValueToOffset(const MCExpr *Offset,
187 unsigned char Value) {
188 new MCOrgFragment(*Offset, Value, getCurrentSectionData());
189 }
190
EmitInstToFragment(const MCInst & Inst)191 void MCPureStreamer::EmitInstToFragment(const MCInst &Inst) {
192 MCInstFragment *IF = new MCInstFragment(Inst, getCurrentSectionData());
193
194 // Add the fixups and data.
195 //
196 // FIXME: Revisit this design decision when relaxation is done, we may be
197 // able to get away with not storing any extra data in the MCInst.
198 SmallVector<MCFixup, 4> Fixups;
199 SmallString<256> Code;
200 raw_svector_ostream VecOS(Code);
201 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
202 VecOS.flush();
203
204 IF->getCode() = Code;
205 IF->getFixups() = Fixups;
206 }
207
EmitInstToData(const MCInst & Inst)208 void MCPureStreamer::EmitInstToData(const MCInst &Inst) {
209 MCDataFragment *DF = getOrCreateDataFragment();
210
211 SmallVector<MCFixup, 4> Fixups;
212 SmallString<256> Code;
213 raw_svector_ostream VecOS(Code);
214 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
215 VecOS.flush();
216
217 // Add the fixups and data.
218 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
219 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
220 DF->addFixup(Fixups[i]);
221 }
222 DF->getContents().append(Code.begin(), Code.end());
223 }
224
Finish()225 void MCPureStreamer::Finish() {
226 // FIXME: Handle DWARF tables?
227
228 this->MCObjectStreamer::Finish();
229 }
230
createPureStreamer(MCContext & Context,TargetAsmBackend & TAB,raw_ostream & OS,MCCodeEmitter * CE)231 MCStreamer *llvm::createPureStreamer(MCContext &Context, TargetAsmBackend &TAB,
232 raw_ostream &OS, MCCodeEmitter *CE) {
233 return new MCPureStreamer(Context, TAB, OS, CE);
234 }
235