MCStreamer.cpp revision 40a7dbbeff44c4cbd8c7e4f07f28dd614f8a5d08 
1//===- lib/MC/MCStreamer.cpp - Streaming Machine Code 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/MCAsmInfo.h"
11#include "llvm/MC/MCContext.h"
12#include "llvm/MC/MCStreamer.h"
13#include "llvm/MC/MCExpr.h"
14#include "llvm/MC/MCObjectWriter.h"
15#include "llvm/MC/MCSymbol.h"
16#include "llvm/Support/ErrorHandling.h"
17#include "llvm/Support/raw_ostream.h"
18#include "llvm/ADT/SmallString.h"
19#include "llvm/ADT/Twine.h"
20#include <cstdlib>
21using namespace llvm;
22
23MCStreamer::MCStreamer(MCContext &Ctx) : Context(Ctx), EmitEHFrame(true),
24                                         EmitDebugFrame(false) {
25  const MCSection *section = NULL;
26  SectionStack.push_back(std::make_pair(section, section));
27}
28
29MCStreamer::~MCStreamer() {
30}
31
32const MCExpr *MCStreamer::BuildSymbolDiff(MCContext &Context,
33                                          const MCSymbol *A,
34                                          const MCSymbol *B) {
35  MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
36  const MCExpr *ARef =
37    MCSymbolRefExpr::Create(A, Variant, Context);
38  const MCExpr *BRef =
39    MCSymbolRefExpr::Create(B, Variant, Context);
40  const MCExpr *AddrDelta =
41    MCBinaryExpr::Create(MCBinaryExpr::Sub, ARef, BRef, Context);
42  return AddrDelta;
43}
44
45const MCExpr *MCStreamer::ForceExpAbs(MCStreamer *Streamer,
46                                      MCContext &Context, const MCExpr* Expr) {
47 if (Context.getAsmInfo().hasAggressiveSymbolFolding())
48   return Expr;
49
50 MCSymbol *ABS = Context.CreateTempSymbol();
51 Streamer->EmitAssignment(ABS, Expr);
52 return MCSymbolRefExpr::Create(ABS, Context);
53}
54
55raw_ostream &MCStreamer::GetCommentOS() {
56  // By default, discard comments.
57  return nulls();
58}
59
60void MCStreamer::EmitDwarfSetLineAddr(int64_t LineDelta,
61                                      const MCSymbol *Label, int PointerSize) {
62  // emit the sequence to set the address
63  EmitIntValue(dwarf::DW_LNS_extended_op, 1);
64  EmitULEB128IntValue(PointerSize + 1);
65  EmitIntValue(dwarf::DW_LNE_set_address, 1);
66  EmitSymbolValue(Label, PointerSize);
67
68  // emit the sequence for the LineDelta (from 1) and a zero address delta.
69  MCDwarfLineAddr::Emit(this, LineDelta, 0);
70}
71
72/// EmitIntValue - Special case of EmitValue that avoids the client having to
73/// pass in a MCExpr for constant integers.
74void MCStreamer::EmitIntValue(uint64_t Value, unsigned Size,
75                              unsigned AddrSpace) {
76  assert(Size <= 8 && "Invalid size");
77  assert((isUIntN(8 * Size, Value) || isIntN(8 * Size, Value)) &&
78         "Invalid size");
79  char buf[8];
80  // FIXME: Endianness assumption.
81  for (unsigned i = 0; i != Size; ++i)
82    buf[i] = uint8_t(Value >> (i * 8));
83  EmitBytes(StringRef(buf, Size), AddrSpace);
84}
85
86/// EmitULEB128Value - Special case of EmitULEB128Value that avoids the
87/// client having to pass in a MCExpr for constant integers.
88void MCStreamer::EmitULEB128IntValue(uint64_t Value, unsigned AddrSpace) {
89  SmallString<32> Tmp;
90  raw_svector_ostream OSE(Tmp);
91  MCObjectWriter::EncodeULEB128(Value, OSE);
92  EmitBytes(OSE.str(), AddrSpace);
93}
94
95/// EmitSLEB128Value - Special case of EmitSLEB128Value that avoids the
96/// client having to pass in a MCExpr for constant integers.
97void MCStreamer::EmitSLEB128IntValue(int64_t Value, unsigned AddrSpace) {
98  SmallString<32> Tmp;
99  raw_svector_ostream OSE(Tmp);
100  MCObjectWriter::EncodeSLEB128(Value, OSE);
101  EmitBytes(OSE.str(), AddrSpace);
102}
103
104void MCStreamer::EmitAbsValue(const MCExpr *Value, unsigned Size,
105                              unsigned AddrSpace) {
106  if (getContext().getAsmInfo().hasAggressiveSymbolFolding()) {
107    EmitValue(Value, Size, AddrSpace);
108    return;
109  }
110  MCSymbol *ABS = getContext().CreateTempSymbol();
111  EmitAssignment(ABS, Value);
112  EmitSymbolValue(ABS, Size, AddrSpace);
113}
114
115
116void MCStreamer::EmitValue(const MCExpr *Value, unsigned Size,
117                           unsigned AddrSpace) {
118  EmitValueImpl(Value, Size, AddrSpace);
119}
120
121void MCStreamer::EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
122                                  unsigned AddrSpace) {
123  EmitValueImpl(MCSymbolRefExpr::Create(Sym, getContext()), Size,
124                AddrSpace);
125}
126
127void MCStreamer::EmitGPRel32Value(const MCExpr *Value) {
128  report_fatal_error("unsupported directive in streamer");
129}
130
131/// EmitFill - Emit NumBytes bytes worth of the value specified by
132/// FillValue.  This implements directives such as '.space'.
133void MCStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue,
134                          unsigned AddrSpace) {
135  const MCExpr *E = MCConstantExpr::Create(FillValue, getContext());
136  for (uint64_t i = 0, e = NumBytes; i != e; ++i)
137    EmitValue(E, 1, AddrSpace);
138}
139
140bool MCStreamer::EmitDwarfFileDirective(unsigned FileNo,
141                                        StringRef Filename) {
142  return getContext().GetDwarfFile(Filename, FileNo) == 0;
143}
144
145void MCStreamer::EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
146                                       unsigned Column, unsigned Flags,
147                                       unsigned Isa,
148                                       unsigned Discriminator,
149                                       StringRef FileName) {
150  getContext().setCurrentDwarfLoc(FileNo, Line, Column, Flags, Isa,
151                                  Discriminator);
152}
153
154MCDwarfFrameInfo *MCStreamer::getCurrentFrameInfo() {
155  if (FrameInfos.empty())
156    return NULL;
157  return &FrameInfos.back();
158}
159
160void MCStreamer::EnsureValidFrame() {
161  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
162  if (!CurFrame || CurFrame->End)
163    report_fatal_error("No open frame");
164}
165
166void MCStreamer::EmitEHSymAttributes(const MCSymbol *Symbol,
167                                     MCSymbol *EHSymbol) {
168}
169
170void MCStreamer::EmitLabel(MCSymbol *Symbol) {
171  assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
172  assert(getCurrentSection() && "Cannot emit before setting section!");
173  Symbol->setSection(*getCurrentSection());
174
175  StringRef Prefix = getContext().getAsmInfo().getPrivateGlobalPrefix();
176  if (!Symbol->getName().startswith(Prefix))
177    LastNonPrivate = Symbol;
178}
179
180void MCStreamer::EmitCFISections(bool EH, bool Debug) {
181  EmitEHFrame = EH;
182  EmitDebugFrame = Debug;
183}
184
185void MCStreamer::EmitCFIStartProc() {
186  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
187  if (CurFrame && !CurFrame->End)
188    report_fatal_error("Starting a frame before finishing the previous one!");
189  MCDwarfFrameInfo Frame;
190  Frame.Begin = getContext().CreateTempSymbol();
191  Frame.Function = LastNonPrivate;
192  EmitLabel(Frame.Begin);
193  FrameInfos.push_back(Frame);
194}
195
196void MCStreamer::EmitCFIEndProc() {
197  EnsureValidFrame();
198  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
199  CurFrame->End = getContext().CreateTempSymbol();
200  EmitLabel(CurFrame->End);
201}
202
203void MCStreamer::EmitCFIDefCfa(int64_t Register, int64_t Offset) {
204  EnsureValidFrame();
205  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
206  MCSymbol *Label = getContext().CreateTempSymbol();
207  EmitLabel(Label);
208  MachineLocation Dest(MachineLocation::VirtualFP);
209  MachineLocation Source(Register, -Offset);
210  MCCFIInstruction Instruction(Label, Dest, Source);
211  CurFrame->Instructions.push_back(Instruction);
212}
213
214void MCStreamer::EmitCFIDefCfaOffset(int64_t Offset) {
215  EnsureValidFrame();
216  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
217  MCSymbol *Label = getContext().CreateTempSymbol();
218  EmitLabel(Label);
219  MachineLocation Dest(MachineLocation::VirtualFP);
220  MachineLocation Source(MachineLocation::VirtualFP, -Offset);
221  MCCFIInstruction Instruction(Label, Dest, Source);
222  CurFrame->Instructions.push_back(Instruction);
223}
224
225void MCStreamer::EmitCFIAdjustCfaOffset(int64_t Adjustment) {
226  EnsureValidFrame();
227  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
228  MCSymbol *Label = getContext().CreateTempSymbol();
229  EmitLabel(Label);
230  MachineLocation Dest(MachineLocation::VirtualFP);
231  MachineLocation Source(MachineLocation::VirtualFP, Adjustment);
232  MCCFIInstruction Instruction(MCCFIInstruction::RelMove, Label, Dest, Source);
233  CurFrame->Instructions.push_back(Instruction);
234}
235
236void MCStreamer::EmitCFIDefCfaRegister(int64_t Register) {
237  EnsureValidFrame();
238  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
239  MCSymbol *Label = getContext().CreateTempSymbol();
240  EmitLabel(Label);
241  MachineLocation Dest(Register);
242  MachineLocation Source(MachineLocation::VirtualFP);
243  MCCFIInstruction Instruction(Label, Dest, Source);
244  CurFrame->Instructions.push_back(Instruction);
245}
246
247void MCStreamer::EmitCFIOffset(int64_t Register, int64_t Offset) {
248  EnsureValidFrame();
249  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
250  MCSymbol *Label = getContext().CreateTempSymbol();
251  EmitLabel(Label);
252  MachineLocation Dest(Register, Offset);
253  MachineLocation Source(Register, Offset);
254  MCCFIInstruction Instruction(Label, Dest, Source);
255  CurFrame->Instructions.push_back(Instruction);
256}
257
258void MCStreamer::EmitCFIRelOffset(int64_t Register, int64_t Offset) {
259  EnsureValidFrame();
260  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
261  MCSymbol *Label = getContext().CreateTempSymbol();
262  EmitLabel(Label);
263  MachineLocation Dest(Register, Offset);
264  MachineLocation Source(Register, Offset);
265  MCCFIInstruction Instruction(MCCFIInstruction::RelMove, Label, Dest, Source);
266  CurFrame->Instructions.push_back(Instruction);
267}
268
269void MCStreamer::EmitCFIPersonality(const MCSymbol *Sym,
270                                    unsigned Encoding) {
271  EnsureValidFrame();
272  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
273  CurFrame->Personality = Sym;
274  CurFrame->PersonalityEncoding = Encoding;
275}
276
277void MCStreamer::EmitCFILsda(const MCSymbol *Sym, unsigned Encoding) {
278  EnsureValidFrame();
279  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
280  CurFrame->Lsda = Sym;
281  CurFrame->LsdaEncoding = Encoding;
282}
283
284void MCStreamer::EmitCFIRememberState() {
285  EnsureValidFrame();
286  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
287  MCSymbol *Label = getContext().CreateTempSymbol();
288  EmitLabel(Label);
289  MCCFIInstruction Instruction(MCCFIInstruction::Remember, Label);
290  CurFrame->Instructions.push_back(Instruction);
291}
292
293void MCStreamer::EmitCFIRestoreState() {
294  // FIXME: Error if there is no matching cfi_remember_state.
295  EnsureValidFrame();
296  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
297  MCSymbol *Label = getContext().CreateTempSymbol();
298  EmitLabel(Label);
299  MCCFIInstruction Instruction(MCCFIInstruction::Restore, Label);
300  CurFrame->Instructions.push_back(Instruction);
301}
302
303void MCStreamer::EmitCFISameValue(int64_t Register) {
304  EnsureValidFrame();
305  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
306  MCSymbol *Label = getContext().CreateTempSymbol();
307  EmitLabel(Label);
308  MCCFIInstruction Instruction(MCCFIInstruction::SameValue, Label, Register);
309  CurFrame->Instructions.push_back(Instruction);
310}
311
312void MCStreamer::EmitFnStart() {
313  errs() << "Not implemented yet\n";
314  abort();
315}
316
317void MCStreamer::EmitFnEnd() {
318  errs() << "Not implemented yet\n";
319  abort();
320}
321
322void MCStreamer::EmitCantUnwind() {
323  errs() << "Not implemented yet\n";
324  abort();
325}
326
327void MCStreamer::EmitHandlerData() {
328  errs() << "Not implemented yet\n";
329  abort();
330}
331
332void MCStreamer::EmitPersonality(const MCSymbol *Personality) {
333  errs() << "Not implemented yet\n";
334  abort();
335}
336
337void MCStreamer::EmitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset) {
338  errs() << "Not implemented yet\n";
339  abort();
340}
341
342void MCStreamer::EmitPad(int64_t Offset) {
343  errs() << "Not implemented yet\n";
344  abort();
345}
346
347void MCStreamer::EmitRegSave(const SmallVectorImpl<unsigned> &RegList, bool) {
348  errs() << "Not implemented yet\n";
349  abort();
350}
351
352/// EmitRawText - If this file is backed by an assembly streamer, this dumps
353/// the specified string in the output .s file.  This capability is
354/// indicated by the hasRawTextSupport() predicate.
355void MCStreamer::EmitRawText(StringRef String) {
356  errs() << "EmitRawText called on an MCStreamer that doesn't support it, "
357  " something must not be fully mc'ized\n";
358  abort();
359}
360
361void MCStreamer::EmitRawText(const Twine &T) {
362  SmallString<128> Str;
363  T.toVector(Str);
364  EmitRawText(Str.str());
365}
366
367void MCStreamer::EmitFrames(bool usingCFI) {
368  if (!getNumFrameInfos())
369    return;
370
371  if (EmitEHFrame)
372    MCDwarfFrameEmitter::Emit(*this, usingCFI, true);
373
374  if (EmitDebugFrame)
375    MCDwarfFrameEmitter::Emit(*this, usingCFI, false);
376}
377