MCStreamer.cpp revision 1c952b9cc98e84b28f68f0f6cf11197263f89863 
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/Support/ErrorHandling.h"
16#include "llvm/Support/raw_ostream.h"
17#include "llvm/ADT/SmallString.h"
18#include "llvm/ADT/Twine.h"
19#include <cstdlib>
20using namespace llvm;
21
22MCStreamer::MCStreamer(MCContext &Ctx) : Context(Ctx), CurSection(0),
23                                         PrevSection(0) {
24}
25
26MCStreamer::~MCStreamer() {
27}
28
29raw_ostream &MCStreamer::GetCommentOS() {
30  // By default, discard comments.
31  return nulls();
32}
33
34void MCStreamer::EmitDwarfSetLineAddr(int64_t LineDelta,
35                                      const MCSymbol *Label, int PointerSize) {
36  // emit the sequence to set the address
37  EmitIntValue(dwarf::DW_LNS_extended_op, 1);
38  EmitULEB128IntValue(PointerSize + 1);
39  EmitIntValue(dwarf::DW_LNE_set_address, 1);
40  EmitSymbolValue(Label, PointerSize);
41
42  // emit the sequence for the LineDelta (from 1) and a zero address delta.
43  MCDwarfLineAddr::Emit(this, LineDelta, 0);
44}
45
46/// EmitIntValue - Special case of EmitValue that avoids the client having to
47/// pass in a MCExpr for constant integers.
48void MCStreamer::EmitIntValue(uint64_t Value, unsigned Size,
49                              unsigned AddrSpace) {
50  assert(Size <= 8 && "Invalid size");
51  assert(!(Size == 1 && (signed)Value > 255) && "Invalid size");
52  char buf[8];
53  // FIXME: Endianness assumption.
54  for (unsigned i = 0; i != Size; ++i)
55    buf[i] = uint8_t(Value >> (i * 8));
56  EmitBytes(StringRef(buf, Size), AddrSpace);
57}
58
59/// EmitULEB128Value - Special case of EmitULEB128Value that avoids the
60/// client having to pass in a MCExpr for constant integers.
61void MCStreamer::EmitULEB128IntValue(uint64_t Value, unsigned AddrSpace) {
62  SmallString<32> Tmp;
63  raw_svector_ostream OSE(Tmp);
64  MCObjectWriter::EncodeULEB128(Value, OSE);
65  EmitBytes(OSE.str(), AddrSpace);
66}
67
68/// EmitSLEB128Value - Special case of EmitSLEB128Value that avoids the
69/// client having to pass in a MCExpr for constant integers.
70void MCStreamer::EmitSLEB128IntValue(int64_t Value, unsigned AddrSpace) {
71  SmallString<32> Tmp;
72  raw_svector_ostream OSE(Tmp);
73  MCObjectWriter::EncodeSLEB128(Value, OSE);
74  EmitBytes(OSE.str(), AddrSpace);
75}
76
77void MCStreamer::EmitAbsValue(const MCExpr *Value, unsigned Size,
78                              unsigned AddrSpace) {
79  if (!getContext().getAsmInfo().needsSetToChangeDiffSize()) {
80    EmitValue(Value, Size, AddrSpace);
81    return;
82  }
83  MCSymbol *ABS = getContext().CreateTempSymbol();
84  EmitAssignment(ABS, Value);
85  EmitSymbolValue(ABS, Size, AddrSpace);
86}
87
88
89void MCStreamer::EmitValue(const MCExpr *Value, unsigned Size,
90                           unsigned AddrSpace) {
91  EmitValueImpl(Value, Size, false, AddrSpace);
92}
93
94void MCStreamer::EmitPCRelValue(const MCExpr *Value, unsigned Size,
95                                unsigned AddrSpace) {
96  EmitValueImpl(Value, Size, true, AddrSpace);
97}
98
99void MCStreamer::EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
100                                 bool isPCRel, unsigned AddrSpace) {
101  EmitValueImpl(MCSymbolRefExpr::Create(Sym, getContext()), Size, isPCRel,
102                AddrSpace);
103}
104
105void MCStreamer::EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
106                                 unsigned AddrSpace) {
107  EmitSymbolValue(Sym, Size, false, AddrSpace);
108}
109
110void MCStreamer::EmitPCRelSymbolValue(const MCSymbol *Sym, unsigned Size,
111                                      unsigned AddrSpace) {
112  EmitSymbolValue(Sym, Size, true, AddrSpace);
113}
114
115void MCStreamer::EmitGPRel32Value(const MCExpr *Value) {
116  report_fatal_error("unsupported directive in streamer");
117}
118
119/// EmitFill - Emit NumBytes bytes worth of the value specified by
120/// FillValue.  This implements directives such as '.space'.
121void MCStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue,
122                          unsigned AddrSpace) {
123  const MCExpr *E = MCConstantExpr::Create(FillValue, getContext());
124  for (uint64_t i = 0, e = NumBytes; i != e; ++i)
125    EmitValue(E, 1, AddrSpace);
126}
127
128bool MCStreamer::EmitDwarfFileDirective(unsigned FileNo,
129                                        StringRef Filename) {
130  return getContext().GetDwarfFile(Filename, FileNo) == 0;
131}
132
133void MCStreamer::EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
134                                       unsigned Column, unsigned Flags,
135                                       unsigned Isa,
136                                       unsigned Discriminator) {
137  getContext().setCurrentDwarfLoc(FileNo, Line, Column, Flags, Isa,
138                                  Discriminator);
139}
140
141MCDwarfFrameInfo *MCStreamer::getCurrentFrameInfo() {
142  if (FrameInfos.empty())
143    return NULL;
144  return &FrameInfos.back();
145}
146
147void MCStreamer::EnsureValidFrame() {
148  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
149  if (!CurFrame || CurFrame->End)
150    report_fatal_error("No open frame");
151}
152
153bool MCStreamer::EmitCFIStartProc() {
154  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
155  if (CurFrame && !CurFrame->End) {
156    report_fatal_error("Starting a frame before finishing the previous one!");
157    return true;
158  }
159  MCDwarfFrameInfo Frame = {0, 0, 0, 0};
160  Frame.Begin = getContext().CreateTempSymbol();
161  EmitLabel(Frame.Begin);
162  FrameInfos.push_back(Frame);
163  return false;
164}
165
166bool MCStreamer::EmitCFIEndProc() {
167  EnsureValidFrame();
168  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
169  CurFrame->End = getContext().CreateTempSymbol();
170  EmitLabel(CurFrame->End);
171  return false;
172}
173
174bool MCStreamer::EmitCFIDefCfaOffset(int64_t Offset) {
175  EnsureValidFrame();
176  return false;
177}
178
179bool MCStreamer::EmitCFIDefCfaRegister(int64_t Register) {
180  EnsureValidFrame();
181  return false;
182}
183
184bool MCStreamer::EmitCFIOffset(int64_t Register, int64_t Offset) {
185  EnsureValidFrame();
186  return false;
187}
188
189bool MCStreamer::EmitCFIPersonality(const MCSymbol *Sym) {
190  EnsureValidFrame();
191  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
192  CurFrame->Personality = Sym;
193  return false;
194}
195
196bool MCStreamer::EmitCFILsda(const MCSymbol *Sym) {
197  EnsureValidFrame();
198  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
199  CurFrame->Lsda = Sym;
200  return false;
201}
202
203/// EmitRawText - If this file is backed by an assembly streamer, this dumps
204/// the specified string in the output .s file.  This capability is
205/// indicated by the hasRawTextSupport() predicate.
206void MCStreamer::EmitRawText(StringRef String) {
207  errs() << "EmitRawText called on an MCStreamer that doesn't support it, "
208  " something must not be fully mc'ized\n";
209  abort();
210}
211
212void MCStreamer::EmitRawText(const Twine &T) {
213  SmallString<128> Str;
214  T.toVector(Str);
215  EmitRawText(Str.str());
216}
217