MCObjectStreamer.cpp revision 8067adc271d7ccfcd28a238d73942b21a5e2bc62 
1//===- 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
10#include "llvm/MC/MCObjectStreamer.h"
11
12#include "llvm/Support/ErrorHandling.h"
13#include "llvm/MC/MCAssembler.h"
14#include "llvm/MC/MCExpr.h"
15using namespace llvm;
16
17MCObjectStreamer::MCObjectStreamer(MCContext &Context, TargetAsmBackend &TAB,
18                                   raw_ostream &_OS, MCCodeEmitter *_Emitter)
19  : MCStreamer(Context), Assembler(new MCAssembler(Context, TAB,
20                                                   *_Emitter, _OS)),
21    CurSectionData(0)
22{
23}
24
25MCObjectStreamer::~MCObjectStreamer() {
26  delete Assembler;
27}
28
29MCFragment *MCObjectStreamer::getCurrentFragment() const {
30  assert(getCurrentSectionData() && "No current section!");
31
32  if (!getCurrentSectionData()->empty())
33    return &getCurrentSectionData()->getFragmentList().back();
34
35  return 0;
36}
37
38MCDataFragment *MCObjectStreamer::getOrCreateDataFragment() const {
39  MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
40  if (!F)
41    F = new MCDataFragment(getCurrentSectionData());
42  return F;
43}
44
45const MCExpr *MCObjectStreamer::AddValueSymbols(const MCExpr *Value) {
46  switch (Value->getKind()) {
47  case MCExpr::Target: llvm_unreachable("Can't handle target exprs yet!");
48  case MCExpr::Constant:
49    break;
50
51  case MCExpr::Binary: {
52    const MCBinaryExpr *BE = cast<MCBinaryExpr>(Value);
53    AddValueSymbols(BE->getLHS());
54    AddValueSymbols(BE->getRHS());
55    break;
56  }
57
58  case MCExpr::SymbolRef:
59    Assembler->getOrCreateSymbolData(cast<MCSymbolRefExpr>(Value)->getSymbol());
60    break;
61
62  case MCExpr::Unary:
63    AddValueSymbols(cast<MCUnaryExpr>(Value)->getSubExpr());
64    break;
65  }
66
67  return Value;
68}
69
70void MCObjectStreamer::SwitchSection(const MCSection *Section) {
71  assert(Section && "Cannot switch to a null section!");
72
73  // If already in this section, then this is a noop.
74  if (Section == CurSection) return;
75
76  CurSection = Section;
77  CurSectionData = &getAssembler().getOrCreateSectionData(*Section);
78}
79
80void MCObjectStreamer::Finish() {
81  getAssembler().Finish();
82}
83