MCStreamer.cpp revision e194b26ffd23aa464324429323647af4fcb7df7b 
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  unsigned Bits = 8 * Size;
52  (void)Bits;
53  assert((isUIntN(Bits, Value) || isIntN(Bits, Value)) && "Invalid size");
54  char buf[8];
55  // FIXME: Endianness assumption.
56  for (unsigned i = 0; i != Size; ++i)
57    buf[i] = uint8_t(Value >> (i * 8));
58  EmitBytes(StringRef(buf, Size), AddrSpace);
59}
60
61/// EmitULEB128Value - Special case of EmitULEB128Value that avoids the
62/// client having to pass in a MCExpr for constant integers.
63void MCStreamer::EmitULEB128IntValue(uint64_t Value, unsigned AddrSpace) {
64  SmallString<32> Tmp;
65  raw_svector_ostream OSE(Tmp);
66  MCObjectWriter::EncodeULEB128(Value, OSE);
67  EmitBytes(OSE.str(), AddrSpace);
68}
69
70/// EmitSLEB128Value - Special case of EmitSLEB128Value that avoids the
71/// client having to pass in a MCExpr for constant integers.
72void MCStreamer::EmitSLEB128IntValue(int64_t Value, unsigned AddrSpace) {
73  SmallString<32> Tmp;
74  raw_svector_ostream OSE(Tmp);
75  MCObjectWriter::EncodeSLEB128(Value, OSE);
76  EmitBytes(OSE.str(), AddrSpace);
77}
78
79void MCStreamer::EmitAbsValue(const MCExpr *Value, unsigned Size,
80                              unsigned AddrSpace) {
81  if (!getContext().getAsmInfo().needsSetToChangeDiffSize()) {
82    EmitValue(Value, Size, AddrSpace);
83    return;
84  }
85  MCSymbol *ABS = getContext().CreateTempSymbol();
86  EmitAssignment(ABS, Value);
87  EmitSymbolValue(ABS, Size, AddrSpace);
88}
89
90
91void MCStreamer::EmitValue(const MCExpr *Value, unsigned Size,
92                           unsigned AddrSpace) {
93  EmitValueImpl(Value, Size, false, AddrSpace);
94}
95
96void MCStreamer::EmitPCRelValue(const MCExpr *Value, unsigned Size,
97                                unsigned AddrSpace) {
98  EmitValueImpl(Value, Size, true, AddrSpace);
99}
100
101void MCStreamer::EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
102                                 bool isPCRel, unsigned AddrSpace) {
103  EmitValueImpl(MCSymbolRefExpr::Create(Sym, getContext()), Size, isPCRel,
104                AddrSpace);
105}
106
107void MCStreamer::EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
108                                 unsigned AddrSpace) {
109  EmitSymbolValue(Sym, Size, false, AddrSpace);
110}
111
112void MCStreamer::EmitPCRelSymbolValue(const MCSymbol *Sym, unsigned Size,
113                                      unsigned AddrSpace) {
114  EmitSymbolValue(Sym, Size, true, AddrSpace);
115}
116
117void MCStreamer::EmitGPRel32Value(const MCExpr *Value) {
118  report_fatal_error("unsupported directive in streamer");
119}
120
121/// EmitFill - Emit NumBytes bytes worth of the value specified by
122/// FillValue.  This implements directives such as '.space'.
123void MCStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue,
124                          unsigned AddrSpace) {
125  const MCExpr *E = MCConstantExpr::Create(FillValue, getContext());
126  for (uint64_t i = 0, e = NumBytes; i != e; ++i)
127    EmitValue(E, 1, AddrSpace);
128}
129
130bool MCStreamer::EmitDwarfFileDirective(unsigned FileNo,
131                                        StringRef Filename) {
132  return getContext().GetDwarfFile(Filename, FileNo) == 0;
133}
134
135void MCStreamer::EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
136                                       unsigned Column, unsigned Flags,
137                                       unsigned Isa,
138                                       unsigned Discriminator) {
139  getContext().setCurrentDwarfLoc(FileNo, Line, Column, Flags, Isa,
140                                  Discriminator);
141}
142
143MCDwarfFrameInfo *MCStreamer::getCurrentFrameInfo() {
144  if (FrameInfos.empty())
145    return NULL;
146  return &FrameInfos.back();
147}
148
149void MCStreamer::EnsureValidFrame() {
150  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
151  if (!CurFrame || CurFrame->End)
152    report_fatal_error("No open frame");
153}
154
155bool MCStreamer::EmitCFIStartProc() {
156  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
157  if (CurFrame && !CurFrame->End) {
158    report_fatal_error("Starting a frame before finishing the previous one!");
159    return true;
160  }
161  MCDwarfFrameInfo Frame = {0, 0, 0, 0};
162  Frame.Begin = getContext().CreateTempSymbol();
163  EmitLabel(Frame.Begin);
164  FrameInfos.push_back(Frame);
165  return false;
166}
167
168bool MCStreamer::EmitCFIEndProc() {
169  EnsureValidFrame();
170  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
171  CurFrame->End = getContext().CreateTempSymbol();
172  EmitLabel(CurFrame->End);
173  return false;
174}
175
176bool MCStreamer::EmitCFIDefCfaOffset(int64_t Offset) {
177  EnsureValidFrame();
178  return false;
179}
180
181bool MCStreamer::EmitCFIDefCfaRegister(int64_t Register) {
182  EnsureValidFrame();
183  return false;
184}
185
186bool MCStreamer::EmitCFIOffset(int64_t Register, int64_t Offset) {
187  EnsureValidFrame();
188  return false;
189}
190
191bool MCStreamer::EmitCFIPersonality(const MCSymbol *Sym) {
192  EnsureValidFrame();
193  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
194  CurFrame->Personality = Sym;
195  return false;
196}
197
198bool MCStreamer::EmitCFILsda(const MCSymbol *Sym) {
199  EnsureValidFrame();
200  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
201  CurFrame->Lsda = Sym;
202  return false;
203}
204
205/// EmitRawText - If this file is backed by an assembly streamer, this dumps
206/// the specified string in the output .s file.  This capability is
207/// indicated by the hasRawTextSupport() predicate.
208void MCStreamer::EmitRawText(StringRef String) {
209  errs() << "EmitRawText called on an MCStreamer that doesn't support it, "
210  " something must not be fully mc'ized\n";
211  abort();
212}
213
214void MCStreamer::EmitRawText(const Twine &T) {
215  SmallString<128> Str;
216  T.toVector(Str);
217  EmitRawText(Str.str());
218}
219