1 //===- lib/MC/MCSectionCOFF.cpp - COFF Code Section Representation --------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "llvm/MC/MCSectionCOFF.h"
10 #include "llvm/BinaryFormat/COFF.h"
11 #include "llvm/MC/MCSymbol.h"
12 #include "llvm/Support/raw_ostream.h"
13 #include <cassert>
14
15 using namespace llvm;
16
17 // ShouldOmitSectionDirective - Decides whether a '.section' directive
18 // should be printed before the section name
ShouldOmitSectionDirective(StringRef Name,const MCAsmInfo & MAI) const19 bool MCSectionCOFF::ShouldOmitSectionDirective(StringRef Name,
20 const MCAsmInfo &MAI) const {
21 if (COMDATSymbol)
22 return false;
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
setSelection(int Selection) const31 void MCSectionCOFF::setSelection(int Selection) const {
32 assert(Selection != 0 && "invalid COMDAT selection type");
33 this->Selection = Selection;
34 Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
35 }
36
PrintSwitchToSection(const MCAsmInfo & MAI,const Triple & T,raw_ostream & OS,const MCExpr * Subsection) const37 void MCSectionCOFF::PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
38 raw_ostream &OS,
39 const MCExpr *Subsection) const {
40 // standard sections don't require the '.section'
41 if (ShouldOmitSectionDirective(getName(), MAI)) {
42 OS << '\t' << getName() << '\n';
43 return;
44 }
45
46 OS << "\t.section\t" << getName() << ",\"";
47 if (getCharacteristics() & COFF::IMAGE_SCN_CNT_INITIALIZED_DATA)
48 OS << 'd';
49 if (getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA)
50 OS << 'b';
51 if (getCharacteristics() & COFF::IMAGE_SCN_MEM_EXECUTE)
52 OS << 'x';
53 if (getCharacteristics() & COFF::IMAGE_SCN_MEM_WRITE)
54 OS << 'w';
55 else if (getCharacteristics() & COFF::IMAGE_SCN_MEM_READ)
56 OS << 'r';
57 else
58 OS << 'y';
59 if (getCharacteristics() & COFF::IMAGE_SCN_LNK_REMOVE)
60 OS << 'n';
61 if (getCharacteristics() & COFF::IMAGE_SCN_MEM_SHARED)
62 OS << 's';
63 if ((getCharacteristics() & COFF::IMAGE_SCN_MEM_DISCARDABLE) &&
64 !isImplicitlyDiscardable(getName()))
65 OS << 'D';
66 OS << '"';
67
68 if (getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
69 if (COMDATSymbol)
70 OS << ",";
71 else
72 OS << "\n\t.linkonce\t";
73 switch (Selection) {
74 case COFF::IMAGE_COMDAT_SELECT_NODUPLICATES:
75 OS << "one_only";
76 break;
77 case COFF::IMAGE_COMDAT_SELECT_ANY:
78 OS << "discard";
79 break;
80 case COFF::IMAGE_COMDAT_SELECT_SAME_SIZE:
81 OS << "same_size";
82 break;
83 case COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH:
84 OS << "same_contents";
85 break;
86 case COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE:
87 OS << "associative";
88 break;
89 case COFF::IMAGE_COMDAT_SELECT_LARGEST:
90 OS << "largest";
91 break;
92 case COFF::IMAGE_COMDAT_SELECT_NEWEST:
93 OS << "newest";
94 break;
95 default:
96 assert(false && "unsupported COFF selection type");
97 break;
98 }
99 if (COMDATSymbol) {
100 OS << ",";
101 COMDATSymbol->print(OS, &MAI);
102 }
103 }
104 OS << '\n';
105 }
106
UseCodeAlign() const107 bool MCSectionCOFF::UseCodeAlign() const {
108 return getKind().isText();
109 }
110
isVirtualSection() const111 bool MCSectionCOFF::isVirtualSection() const {
112 return getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
113 }
114
getVirtualSectionKind() const115 StringRef MCSectionCOFF::getVirtualSectionKind() const {
116 return "IMAGE_SCN_CNT_UNINITIALIZED_DATA";
117 }
118