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1 //===- lib/MC/MCSectionCOFF.cpp - COFF Code Section Representation --------===//
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/MCSectionCOFF.h"
11 #include "llvm/MC/MCAsmInfo.h"
12 #include "llvm/MC/MCContext.h"
13 #include "llvm/MC/MCSymbol.h"
14 #include "llvm/Support/raw_ostream.h"
15 using namespace llvm;
16 
~MCSectionCOFF()17 MCSectionCOFF::~MCSectionCOFF() {} // anchor.
18 
19 // ShouldOmitSectionDirective - Decides whether a '.section' directive
20 // should be printed before the section name
ShouldOmitSectionDirective(StringRef Name,const MCAsmInfo & MAI) const21 bool MCSectionCOFF::ShouldOmitSectionDirective(StringRef Name,
22                                                const MCAsmInfo &MAI) const {
23 
24   // FIXME: Does .section .bss/.data/.text work everywhere??
25   if (Name == ".text" || Name == ".data" || Name == ".bss")
26     return true;
27 
28   return false;
29 }
30 
PrintSwitchToSection(const MCAsmInfo & MAI,raw_ostream & OS) const31 void MCSectionCOFF::PrintSwitchToSection(const MCAsmInfo &MAI,
32                                          raw_ostream &OS) const {
33 
34   // standard sections don't require the '.section'
35   if (ShouldOmitSectionDirective(SectionName, MAI)) {
36     OS << '\t' << getSectionName() << '\n';
37     return;
38   }
39 
40   OS << "\t.section\t" << getSectionName() << ",\"";
41   if (getKind().isText())
42     OS << 'x';
43   if (getKind().isWriteable())
44     OS << 'w';
45   else
46     OS << 'r';
47   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_DISCARDABLE)
48     OS << 'n';
49   OS << "\"\n";
50 
51   if (getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
52     switch (Selection) {
53       case COFF::IMAGE_COMDAT_SELECT_NODUPLICATES:
54         OS << "\t.linkonce one_only\n";
55         break;
56       case COFF::IMAGE_COMDAT_SELECT_ANY:
57         OS << "\t.linkonce discard\n";
58         break;
59       case COFF::IMAGE_COMDAT_SELECT_SAME_SIZE:
60         OS << "\t.linkonce same_size\n";
61         break;
62       case COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH:
63         OS << "\t.linkonce same_contents\n";
64         break;
65     //NOTE: as of binutils 2.20, there is no way to specifiy select largest
66     //      with the .linkonce directive. For now, we treat it as an invalid
67     //      comdat selection value.
68       case COFF::IMAGE_COMDAT_SELECT_LARGEST:
69     //  OS << "\t.linkonce largest\n";
70     //  break;
71       default:
72         assert (0 && "unsupported COFF selection type");
73         break;
74     }
75   }
76 }
77 
UseCodeAlign() const78 bool MCSectionCOFF::UseCodeAlign() const {
79   return getKind().isText();
80 }
81 
isVirtualSection() const82 bool MCSectionCOFF::isVirtualSection() const {
83   return getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
84 }
85