1//===- MCSectionXCOFF.h - XCOFF Machine Code Sections -----------*- C++ -*-===//
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// This file declares the MCSectionXCOFF class.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_MC_MCSECTIONXCOFF_H
14#define LLVM_MC_MCSECTIONXCOFF_H
15
16#include "llvm/BinaryFormat/XCOFF.h"
17#include "llvm/MC/MCSection.h"
18#include "llvm/MC/MCSymbolXCOFF.h"
19
20namespace llvm {
21
22// This class represents an XCOFF `Control Section`, more commonly referred to
23// as a csect. A csect represents the smallest possible unit of data/code which
24// will be relocated as a single block. A csect can either be:
25// 1) Initialized: The Type will be XTY_SD, and the symbols inside the csect
26// will have a label definition representing their offset within the csect.
27// 2) Uninitialized: The Type will be XTY_CM, it will contain a single symbol,
28// and may not contain label definitions.
29// 3) An external reference providing a symbol table entry for a symbol
30// contained in another XCOFF object file. External reference csects are not
31// implemented yet.
32class MCSectionXCOFF final : public MCSection {
33 friend class MCContext;
34
35 std::optional<XCOFF::CsectProperties> CsectProp;
36 MCSymbolXCOFF *const QualName;
37 StringRef SymbolTableName;
38 std::optional<XCOFF::DwarfSectionSubtypeFlags> DwarfSubtypeFlags;
39 bool MultiSymbolsAllowed;
40 static constexpr unsigned DefaultAlignVal = 4;
41 static constexpr unsigned DefaultTextAlignVal = 32;
42
43 MCSectionXCOFF(StringRef Name, XCOFF::StorageMappingClass SMC,
44 XCOFF::SymbolType ST, SectionKind K, MCSymbolXCOFF *QualName,
45 MCSymbol *Begin, StringRef SymbolTableName,
46 bool MultiSymbolsAllowed)
47 : MCSection(SV_XCOFF, Name, K, Begin),
48 CsectProp(XCOFF::CsectProperties(SMC, ST)), QualName(QualName),
49 SymbolTableName(SymbolTableName), DwarfSubtypeFlags(std::nullopt),
50 MultiSymbolsAllowed(MultiSymbolsAllowed) {
51 assert(
52 (ST == XCOFF::XTY_SD || ST == XCOFF::XTY_CM || ST == XCOFF::XTY_ER) &&
53 "Invalid or unhandled type for csect.");
54 assert(QualName != nullptr && "QualName is needed.");
55 if (SMC == XCOFF::XMC_UL)
56 assert((ST == XCOFF::XTY_CM || ST == XCOFF::XTY_ER) &&
57 "Invalid csect type for storage mapping class XCOFF::XMC_UL");
58
59 QualName->setRepresentedCsect(this);
60 QualName->setStorageClass(XCOFF::C_HIDEXT);
61 if (ST != XCOFF::XTY_ER) {
62 // For a csect for program code, set the alignment to 32 bytes by default.
63 // For other csects, set the alignment to 4 bytes by default.
64 if (SMC == XCOFF::XMC_PR)
65 setAlignment(Align(DefaultTextAlignVal));
66 else
67 setAlignment(Align(DefaultAlignVal));
68 }
69 }
70
71 MCSectionXCOFF(StringRef Name, SectionKind K, MCSymbolXCOFF *QualName,
72 XCOFF::DwarfSectionSubtypeFlags DwarfSubtypeFlags,
73 MCSymbol *Begin, StringRef SymbolTableName,
74 bool MultiSymbolsAllowed)
75 : MCSection(SV_XCOFF, Name, K, Begin), QualName(QualName),
76 SymbolTableName(SymbolTableName), DwarfSubtypeFlags(DwarfSubtypeFlags),
77 MultiSymbolsAllowed(MultiSymbolsAllowed) {
78 assert(QualName != nullptr && "QualName is needed.");
79
80 // FIXME: use a more meaningful name for non csect sections.
81 QualName->setRepresentedCsect(this);
82
83 // Use default text alignment as the alignment for DWARF sections.
84 setAlignment(Align(DefaultTextAlignVal));
85 }
86
87 void printCsectDirective(raw_ostream &OS) const;
88
89public:
90 ~MCSectionXCOFF();
91
92 static bool classof(const MCSection *S) {
93 return S->getVariant() == SV_XCOFF;
94 }
95
96 XCOFF::StorageMappingClass getMappingClass() const {
97 assert(isCsect() && "Only csect section has mapping class property!");
98 return CsectProp->MappingClass;
99 }
100 XCOFF::StorageClass getStorageClass() const {
101 return QualName->getStorageClass();
102 }
103 XCOFF::VisibilityType getVisibilityType() const {
104 return QualName->getVisibilityType();
105 }
106 XCOFF::SymbolType getCSectType() const {
107 assert(isCsect() && "Only csect section has symbol type property!");
108 return CsectProp->Type;
109 }
110 MCSymbolXCOFF *getQualNameSymbol() const { return QualName; }
111
112 void printSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
113 raw_ostream &OS,
114 const MCExpr *Subsection) const override;
115 bool useCodeAlign() const override;
116 bool isVirtualSection() const override;
117 StringRef getSymbolTableName() const { return SymbolTableName; }
118 void setSymbolTableName(StringRef STN) { SymbolTableName = STN; }
119 bool isMultiSymbolsAllowed() const { return MultiSymbolsAllowed; }
120 bool isCsect() const { return CsectProp.has_value(); }
121 bool isDwarfSect() const { return DwarfSubtypeFlags.has_value(); }
122 std::optional<XCOFF::DwarfSectionSubtypeFlags> getDwarfSubtypeFlags() const {
123 return DwarfSubtypeFlags;
124 }
125 std::optional<XCOFF::CsectProperties> getCsectProp() const {
126 return CsectProp;
127 }
128};
129
130} // end namespace llvm
131
132#endif
133

source code of llvm/include/llvm/MC/MCSectionXCOFF.h