1 //===- MCSection.h - Machine Code Sections ----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares the MCSection class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_MC_MCSECTION_H
15 #define LLVM_MC_MCSECTION_H
17 #include "llvm/ADT/SmallVector.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/ADT/ilist.h"
20 #include "llvm/ADT/ilist_node.h"
21 #include "llvm/MC/SectionKind.h"
22 #include "llvm/Support/Compiler.h"
34 /// Instances of this class represent a uniqued identifier for a section in the
35 /// current translation unit. The MCContext class uniques and creates these.
38 enum SectionVariant { SV_COFF = 0, SV_ELF, SV_MachO };
40 /// \brief Express the state of bundle locked groups while emitting code.
41 enum BundleLockStateType {
44 BundleLockedAlignToEnd
47 typedef iplist<MCFragment> FragmentListType;
49 typedef FragmentListType::const_iterator const_iterator;
50 typedef FragmentListType::iterator iterator;
52 typedef FragmentListType::const_reverse_iterator const_reverse_iterator;
53 typedef FragmentListType::reverse_iterator reverse_iterator;
56 MCSection(const MCSection &) = delete;
57 void operator=(const MCSection &) = delete;
60 MCSymbol *End = nullptr;
61 /// The alignment requirement of this section.
62 unsigned Alignment = 1;
63 /// The section index in the assemblers section list.
65 /// The index of this section in the layout order.
68 /// \brief Keeping track of bundle-locked state.
69 BundleLockStateType BundleLockState = NotBundleLocked;
71 /// \brief Current nesting depth of bundle_lock directives.
72 unsigned BundleLockNestingDepth = 0;
74 /// \brief We've seen a bundle_lock directive but not its first instruction
76 bool BundleGroupBeforeFirstInst = false;
78 /// Whether this section has had instructions emitted into it.
79 unsigned HasInstructions : 1;
81 FragmentListType Fragments;
83 /// Mapping from subsection number to insertion point for subsection numbers
84 /// below that number.
85 SmallVector<std::pair<unsigned, MCFragment *>, 1> SubsectionFragmentMap;
88 MCSection(SectionVariant V, SectionKind K, MCSymbol *Begin);
89 SectionVariant Variant;
95 SectionKind getKind() const { return Kind; }
97 SectionVariant getVariant() const { return Variant; }
99 MCSymbol *getBeginSymbol() { return Begin; }
100 const MCSymbol *getBeginSymbol() const {
101 return const_cast<MCSection *>(this)->getBeginSymbol();
103 void setBeginSymbol(MCSymbol *Sym) {
107 MCSymbol *getEndSymbol(MCContext &Ctx);
108 bool hasEnded() const;
110 unsigned getAlignment() const { return Alignment; }
111 void setAlignment(unsigned Value) { Alignment = Value; }
113 unsigned getOrdinal() const { return Ordinal; }
114 void setOrdinal(unsigned Value) { Ordinal = Value; }
116 unsigned getLayoutOrder() const { return LayoutOrder; }
117 void setLayoutOrder(unsigned Value) { LayoutOrder = Value; }
119 BundleLockStateType getBundleLockState() const { return BundleLockState; }
120 void setBundleLockState(BundleLockStateType NewState);
121 bool isBundleLocked() const { return BundleLockState != NotBundleLocked; }
123 bool isBundleGroupBeforeFirstInst() const {
124 return BundleGroupBeforeFirstInst;
126 void setBundleGroupBeforeFirstInst(bool IsFirst) {
127 BundleGroupBeforeFirstInst = IsFirst;
130 bool hasInstructions() const { return HasInstructions; }
131 void setHasInstructions(bool Value) { HasInstructions = Value; }
133 MCSection::FragmentListType &getFragmentList() { return Fragments; }
134 const MCSection::FragmentListType &getFragmentList() const {
135 return const_cast<MCSection *>(this)->getFragmentList();
138 MCSection::iterator begin();
139 MCSection::const_iterator begin() const {
140 return const_cast<MCSection *>(this)->begin();
143 MCSection::iterator end();
144 MCSection::const_iterator end() const {
145 return const_cast<MCSection *>(this)->end();
148 MCSection::reverse_iterator rbegin();
149 MCSection::const_reverse_iterator rbegin() const {
150 return const_cast<MCSection *>(this)->rbegin();
153 MCSection::reverse_iterator rend();
154 MCSection::const_reverse_iterator rend() const {
155 return const_cast<MCSection *>(this)->rend();
158 MCSection::iterator getSubsectionInsertionPoint(unsigned Subsection);
162 virtual void PrintSwitchToSection(const MCAsmInfo &MAI, raw_ostream &OS,
163 const MCExpr *Subsection) const = 0;
165 /// Return true if a .align directive should use "optimized nops" to fill
167 virtual bool UseCodeAlign() const = 0;
169 /// Check whether this section is "virtual", that is has no actual object
171 virtual bool isVirtualSection() const = 0;
174 } // end namespace llvm