1 | //===- MCSectionELF.h - ELF 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 MCSectionELF class. |
10 | // |
11 | //===----------------------------------------------------------------------===// |
12 | |
13 | #ifndef LLVM_MC_MCSECTIONELF_H |
14 | #define LLVM_MC_MCSECTIONELF_H |
15 | |
16 | #include "llvm/ADT/PointerIntPair.h" |
17 | #include "llvm/ADT/StringRef.h" |
18 | #include "llvm/MC/MCSection.h" |
19 | #include "llvm/MC/MCSymbolELF.h" |
20 | #include "llvm/MC/SectionKind.h" |
21 | |
22 | namespace llvm { |
23 | |
24 | /// This represents a section on linux, lots of unix variants and some bare |
25 | /// metal systems. |
26 | class MCSectionELF final : public MCSection { |
27 | /// This is the sh_type field of a section, drawn from the enums below. |
28 | unsigned Type; |
29 | |
30 | /// This is the sh_flags field of a section, drawn from the enums below. |
31 | unsigned Flags; |
32 | |
33 | unsigned UniqueID; |
34 | |
35 | /// The size of each entry in this section. This size only makes sense for |
36 | /// sections that contain fixed-sized entries. If a section does not contain |
37 | /// fixed-sized entries 'EntrySize' will be 0. |
38 | unsigned EntrySize; |
39 | |
40 | /// The section group signature symbol (if not null) and a bool indicating |
41 | /// whether this is a GRP_COMDAT group. |
42 | const PointerIntPair<const MCSymbolELF *, 1, bool> Group; |
43 | |
44 | /// Used by SHF_LINK_ORDER. If non-null, the sh_link field will be set to the |
45 | /// section header index of the section where LinkedToSym is defined. |
46 | const MCSymbol *LinkedToSym; |
47 | |
48 | private: |
49 | friend class MCContext; |
50 | |
51 | // The storage of Name is owned by MCContext's ELFUniquingMap. |
52 | MCSectionELF(StringRef Name, unsigned type, unsigned flags, SectionKind K, |
53 | unsigned entrySize, const MCSymbolELF *group, bool IsComdat, |
54 | unsigned UniqueID, MCSymbol *Begin, |
55 | const MCSymbolELF *LinkedToSym) |
56 | : MCSection(SV_ELF, Name, K, Begin), Type(type), Flags(flags), |
57 | UniqueID(UniqueID), EntrySize(entrySize), Group(group, IsComdat), |
58 | LinkedToSym(LinkedToSym) { |
59 | if (Group.getPointer()) |
60 | Group.getPointer()->setIsSignature(); |
61 | } |
62 | |
63 | // TODO Delete after we stop supporting generation of GNU-style .zdebug_* |
64 | // sections. |
65 | void setSectionName(StringRef Name) { this->Name = Name; } |
66 | |
67 | public: |
68 | /// Decides whether a '.section' directive should be printed before the |
69 | /// section name |
70 | bool shouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const; |
71 | |
72 | unsigned getType() const { return Type; } |
73 | unsigned getFlags() const { return Flags; } |
74 | unsigned getEntrySize() const { return EntrySize; } |
75 | void setFlags(unsigned F) { Flags = F; } |
76 | const MCSymbolELF *getGroup() const { return Group.getPointer(); } |
77 | bool isComdat() const { return Group.getInt(); } |
78 | |
79 | void printSwitchToSection(const MCAsmInfo &MAI, const Triple &T, |
80 | raw_ostream &OS, |
81 | const MCExpr *Subsection) const override; |
82 | bool useCodeAlign() const override; |
83 | bool isVirtualSection() const override; |
84 | StringRef getVirtualSectionKind() const override; |
85 | |
86 | bool isUnique() const { return UniqueID != NonUniqueID; } |
87 | unsigned getUniqueID() const { return UniqueID; } |
88 | |
89 | const MCSection *getLinkedToSection() const { |
90 | return &LinkedToSym->getSection(); |
91 | } |
92 | const MCSymbol *getLinkedToSymbol() const { return LinkedToSym; } |
93 | |
94 | static bool classof(const MCSection *S) { |
95 | return S->getVariant() == SV_ELF; |
96 | } |
97 | }; |
98 | |
99 | } // end namespace llvm |
100 | |
101 | #endif // LLVM_MC_MCSECTIONELF_H |
102 | |