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 | |
20 | namespace 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. |
32 | class 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 | |
89 | public: |
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 | |