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Daniel Dunbar8dc68ab2010-06-16 20:04:22 +00001//===- lib/MC/MCObjectStreamer.cpp - Object File MCStreamer Interface -----===//
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
Rafael Espindola835439a2010-12-22 22:04:28 +000010#include "llvm/MC/MCAsmInfo.h"
Daniel Dunbar8dc68ab2010-06-16 20:04:22 +000011#include "llvm/MC/MCObjectStreamer.h"
12
Michael J. Spencer8067adc2010-07-19 06:13:10 +000013#include "llvm/Support/ErrorHandling.h"
Daniel Dunbar8dc68ab2010-06-16 20:04:22 +000014#include "llvm/MC/MCAssembler.h"
Benjamin Kramer1abcd062010-07-29 17:48:06 +000015#include "llvm/MC/MCCodeEmitter.h"
Rafael Espindola89b93722010-12-10 07:39:47 +000016#include "llvm/MC/MCContext.h"
Rafael Espindolaf89671d2010-11-01 16:27:31 +000017#include "llvm/MC/MCDwarf.h"
Michael J. Spencer8067adc2010-07-19 06:13:10 +000018#include "llvm/MC/MCExpr.h"
Rafael Espindolaea4afa92010-11-28 17:18:55 +000019#include "llvm/MC/MCSymbol.h"
Benjamin Kramer1abcd062010-07-29 17:48:06 +000020#include "llvm/Target/TargetAsmBackend.h"
Rafael Espindola89b93722010-12-10 07:39:47 +000021#include "llvm/Target/TargetAsmInfo.h"
Daniel Dunbar8dc68ab2010-06-16 20:04:22 +000022using namespace llvm;
23
24MCObjectStreamer::MCObjectStreamer(MCContext &Context, TargetAsmBackend &TAB,
Daniel Dunbarfeb7ba32010-12-17 02:45:41 +000025 raw_ostream &OS, MCCodeEmitter *Emitter_)
26 : MCStreamer(Context),
27 Assembler(new MCAssembler(Context, TAB,
28 *Emitter_, *TAB.createObjectWriter(OS),
29 OS)),
Daniel Dunbar83b46712010-06-16 20:04:25 +000030 CurSectionData(0)
Daniel Dunbar8dc68ab2010-06-16 20:04:22 +000031{
32}
33
34MCObjectStreamer::~MCObjectStreamer() {
Benjamin Kramer1abcd062010-07-29 17:48:06 +000035 delete &Assembler->getBackend();
36 delete &Assembler->getEmitter();
Daniel Dunbarfeb7ba32010-12-17 02:45:41 +000037 delete &Assembler->getWriter();
Daniel Dunbar8dc68ab2010-06-16 20:04:22 +000038 delete Assembler;
39}
Daniel Dunbar83b46712010-06-16 20:04:25 +000040
Michael J. Spencer8067adc2010-07-19 06:13:10 +000041MCFragment *MCObjectStreamer::getCurrentFragment() const {
42 assert(getCurrentSectionData() && "No current section!");
43
44 if (!getCurrentSectionData()->empty())
45 return &getCurrentSectionData()->getFragmentList().back();
46
47 return 0;
48}
49
50MCDataFragment *MCObjectStreamer::getOrCreateDataFragment() const {
51 MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
52 if (!F)
53 F = new MCDataFragment(getCurrentSectionData());
54 return F;
55}
56
57const MCExpr *MCObjectStreamer::AddValueSymbols(const MCExpr *Value) {
58 switch (Value->getKind()) {
59 case MCExpr::Target: llvm_unreachable("Can't handle target exprs yet!");
60 case MCExpr::Constant:
61 break;
62
63 case MCExpr::Binary: {
64 const MCBinaryExpr *BE = cast<MCBinaryExpr>(Value);
65 AddValueSymbols(BE->getLHS());
66 AddValueSymbols(BE->getRHS());
67 break;
68 }
69
70 case MCExpr::SymbolRef:
71 Assembler->getOrCreateSymbolData(cast<MCSymbolRefExpr>(Value)->getSymbol());
72 break;
73
74 case MCExpr::Unary:
75 AddValueSymbols(cast<MCUnaryExpr>(Value)->getSubExpr());
76 break;
77 }
78
79 return Value;
80}
81
Rafael Espindola89b93722010-12-10 07:39:47 +000082void MCObjectStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
83 bool isPCRel, unsigned AddrSpace) {
Rafael Espindola6f950232010-11-28 23:08:47 +000084 assert(AddrSpace == 0 && "Address space must be 0!");
85 MCDataFragment *DF = getOrCreateDataFragment();
86
87 // Avoid fixups when possible.
88 int64_t AbsValue;
Rafael Espindolad0764822010-12-18 03:57:21 +000089 if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue, getAssembler())) {
Rafael Espindola2df042c2010-12-03 02:54:21 +000090 EmitIntValue(AbsValue, Size, AddrSpace);
91 return;
Rafael Espindola6f950232010-11-28 23:08:47 +000092 }
Rafael Espindola2df042c2010-12-03 02:54:21 +000093 DF->addFixup(MCFixup::Create(DF->getContents().size(),
Rafael Espindola835439a2010-12-22 22:04:28 +000094 Value,
Rafael Espindola89b93722010-12-10 07:39:47 +000095 MCFixup::getKindForSize(Size, isPCRel)));
Rafael Espindola2df042c2010-12-03 02:54:21 +000096 DF->getContents().resize(DF->getContents().size() + Size, 0);
Rafael Espindola6f950232010-11-28 23:08:47 +000097}
98
Rafael Espindolaea4afa92010-11-28 17:18:55 +000099void MCObjectStreamer::EmitLabel(MCSymbol *Symbol) {
100 assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
101 assert(CurSection && "Cannot emit before setting section!");
102
103 Symbol->setSection(*CurSection);
104
105 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
106
107 // FIXME: This is wasteful, we don't necessarily need to create a data
108 // fragment. Instead, we should mark the symbol as pointing into the data
109 // fragment if it exists, otherwise we should just queue the label and set its
110 // fragment pointer when we emit the next fragment.
111 MCDataFragment *F = getOrCreateDataFragment();
112 assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
113 SD.setFragment(F);
114 SD.setOffset(F->getContents().size());
115}
116
Rafael Espindola3ff57092010-11-02 17:22:24 +0000117void MCObjectStreamer::EmitULEB128Value(const MCExpr *Value,
118 unsigned AddrSpace) {
Rafael Espindola660b5fc2010-12-03 01:19:49 +0000119 int64_t IntValue;
Rafael Espindolad0764822010-12-18 03:57:21 +0000120 if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
Rafael Espindola660b5fc2010-12-03 01:19:49 +0000121 EmitULEB128IntValue(IntValue, AddrSpace);
122 return;
123 }
Rafael Espindola3ff57092010-11-02 17:22:24 +0000124 new MCLEBFragment(*Value, false, getCurrentSectionData());
125}
126
127void MCObjectStreamer::EmitSLEB128Value(const MCExpr *Value,
128 unsigned AddrSpace) {
Rafael Espindola660b5fc2010-12-03 01:19:49 +0000129 int64_t IntValue;
Rafael Espindolad0764822010-12-18 03:57:21 +0000130 if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
Rafael Espindola660b5fc2010-12-03 01:19:49 +0000131 EmitSLEB128IntValue(IntValue, AddrSpace);
132 return;
133 }
Rafael Espindola3ff57092010-11-02 17:22:24 +0000134 new MCLEBFragment(*Value, true, getCurrentSectionData());
135}
136
Rafael Espindola484291c2010-11-01 14:28:48 +0000137void MCObjectStreamer::EmitWeakReference(MCSymbol *Alias,
138 const MCSymbol *Symbol) {
139 report_fatal_error("This file format doesn't support weak aliases.");
140}
141
Daniel Dunbar83b46712010-06-16 20:04:25 +0000142void MCObjectStreamer::SwitchSection(const MCSection *Section) {
143 assert(Section && "Cannot switch to a null section!");
144
145 // If already in this section, then this is a noop.
146 if (Section == CurSection) return;
147
Benjamin Kramer1674b0b2010-09-02 18:53:37 +0000148 PrevSection = CurSection;
Daniel Dunbar83b46712010-06-16 20:04:25 +0000149 CurSection = Section;
150 CurSectionData = &getAssembler().getOrCreateSectionData(*Section);
151}
152
Rafael Espindolaf89671d2010-11-01 16:27:31 +0000153void MCObjectStreamer::EmitInstruction(const MCInst &Inst) {
154 // Scan for values.
155 for (unsigned i = Inst.getNumOperands(); i--; )
156 if (Inst.getOperand(i).isExpr())
157 AddValueSymbols(Inst.getOperand(i).getExpr());
158
159 getCurrentSectionData()->setHasInstructions(true);
160
161 // Now that a machine instruction has been assembled into this section, make
162 // a line entry for any .loc directive that has been seen.
163 MCLineEntry::Make(this, getCurrentSection());
164
165 // If this instruction doesn't need relaxation, just emit it as data.
166 if (!getAssembler().getBackend().MayNeedRelaxation(Inst)) {
167 EmitInstToData(Inst);
168 return;
169 }
170
171 // Otherwise, if we are relaxing everything, relax the instruction as much as
172 // possible and emit it as data.
173 if (getAssembler().getRelaxAll()) {
174 MCInst Relaxed;
175 getAssembler().getBackend().RelaxInstruction(Inst, Relaxed);
176 while (getAssembler().getBackend().MayNeedRelaxation(Relaxed))
177 getAssembler().getBackend().RelaxInstruction(Relaxed, Relaxed);
178 EmitInstToData(Relaxed);
179 return;
180 }
181
182 // Otherwise emit to a separate fragment.
183 EmitInstToFragment(Inst);
184}
185
Rafael Espindoladedb0452010-12-02 05:44:06 +0000186void MCObjectStreamer::EmitInstToFragment(const MCInst &Inst) {
187 MCInstFragment *IF = new MCInstFragment(Inst, getCurrentSectionData());
188
189 raw_svector_ostream VecOS(IF->getCode());
190 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, IF->getFixups());
191}
192
Rafael Espindola245a1e22010-12-28 05:39:27 +0000193static const MCExpr *BuildSymbolDiff(MCContext &Context,
194 const MCSymbol *A, const MCSymbol *B) {
195 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
196 const MCExpr *ARef =
197 MCSymbolRefExpr::Create(A, Variant, Context);
198 const MCExpr *BRef =
199 MCSymbolRefExpr::Create(B, Variant, Context);
200 const MCExpr *AddrDelta =
201 MCBinaryExpr::Create(MCBinaryExpr::Sub, ARef, BRef, Context);
202 return AddrDelta;
203}
204
205static const MCExpr *ForceExpAbs(MCObjectStreamer *Streamer,
206 MCContext &Context, const MCExpr* Expr) {
207 if (Context.getAsmInfo().hasAggressiveSymbolFolding())
208 return Expr;
209
210 MCSymbol *ABS = Context.CreateTempSymbol();
211 Streamer->EmitAssignment(ABS, Expr);
212 return MCSymbolRefExpr::Create(ABS, Context);
213}
214
Rafael Espindola32a006e2010-12-03 00:55:40 +0000215void MCObjectStreamer::EmitDwarfAdvanceLineAddr(int64_t LineDelta,
216 const MCSymbol *LastLabel,
217 const MCSymbol *Label) {
218 if (!LastLabel) {
Rafael Espindola89b93722010-12-10 07:39:47 +0000219 int PointerSize = getContext().getTargetAsmInfo().getPointerSize();
Rafael Espindola32a006e2010-12-03 00:55:40 +0000220 EmitDwarfSetLineAddr(LineDelta, Label, PointerSize);
221 return;
222 }
Rafael Espindola245a1e22010-12-28 05:39:27 +0000223 const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
Rafael Espindola32a006e2010-12-03 00:55:40 +0000224 int64_t Res;
Rafael Espindolad0764822010-12-18 03:57:21 +0000225 if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
Rafael Espindola32a006e2010-12-03 00:55:40 +0000226 MCDwarfLineAddr::Emit(this, LineDelta, Res);
227 return;
228 }
Rafael Espindola245a1e22010-12-28 05:39:27 +0000229 AddrDelta = ForceExpAbs(this, getContext(), AddrDelta);
Rafael Espindola32a006e2010-12-03 00:55:40 +0000230 new MCDwarfLineAddrFragment(LineDelta, *AddrDelta, getCurrentSectionData());
231}
232
Rafael Espindola245a1e22010-12-28 05:39:27 +0000233void MCObjectStreamer::EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
234 const MCSymbol *Label) {
235 const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
236 int64_t Res;
237 if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
238 MCDwarfFrameEmitter::EmitAdvanceLoc(*this, Res);
239 return;
240 }
241 AddrDelta = ForceExpAbs(this, getContext(), AddrDelta);
242 new MCDwarfCallFrameFragment(*AddrDelta, getCurrentSectionData());
243}
244
Rafael Espindolae2393052010-12-02 05:59:38 +0000245void MCObjectStreamer::EmitValueToOffset(const MCExpr *Offset,
246 unsigned char Value) {
247 new MCOrgFragment(*Offset, Value, getCurrentSectionData());
248}
249
Daniel Dunbar83b46712010-06-16 20:04:25 +0000250void MCObjectStreamer::Finish() {
Rafael Espindola89b93722010-12-10 07:39:47 +0000251 // Dump out the dwarf file & directory tables and line tables.
252 if (getContext().hasDwarfFiles())
253 MCDwarfFileTable::Emit(this);
254
Daniel Dunbar83b46712010-06-16 20:04:25 +0000255 getAssembler().Finish();
256}