1 //===-- llvm/Target/TargetLoweringObjectFile.h - Object Info ----*- 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 implements classes used to handle lowerings specific to common
11 // object file formats.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_TARGET_TARGETLOWERINGOBJECTFILE_H
16 #define LLVM_TARGET_TARGETLOWERINGOBJECTFILE_H
18 #include "llvm/ADT/ArrayRef.h"
19 #include "llvm/IR/Module.h"
20 #include "llvm/MC/MCObjectFileInfo.h"
21 #include "llvm/MC/SectionKind.h"
24 class MachineModuleInfo;
30 class MCSymbolRefExpr;
37 class TargetLoweringObjectFile : public MCObjectFileInfo {
40 TargetLoweringObjectFile(
41 const TargetLoweringObjectFile&) = delete;
42 void operator=(const TargetLoweringObjectFile&) = delete;
46 bool SupportIndirectSymViaGOTPCRel;
47 bool SupportGOTPCRelWithOffset;
50 MCContext &getContext() const { return *Ctx; }
52 TargetLoweringObjectFile() : MCObjectFileInfo(), Ctx(nullptr), DL(nullptr),
53 SupportIndirectSymViaGOTPCRel(false),
54 SupportGOTPCRelWithOffset(true) {}
56 virtual ~TargetLoweringObjectFile();
58 /// This method must be called before any actual lowering is done. This
59 /// specifies the current context for codegen, and gives the lowering
60 /// implementations a chance to set up their default sections.
61 virtual void Initialize(MCContext &ctx, const TargetMachine &TM);
63 virtual void emitPersonalityValue(MCStreamer &Streamer,
64 const TargetMachine &TM,
65 const MCSymbol *Sym) const;
67 /// Extract the dependent library name from a linker option string. Returns
68 /// StringRef() if the option does not specify a library.
69 virtual StringRef getDepLibFromLinkerOpt(StringRef LinkerOption) const {
73 /// Emit the module flags that the platform cares about.
74 virtual void emitModuleFlags(MCStreamer &Streamer,
75 ArrayRef<Module::ModuleFlagEntry> Flags,
76 Mangler &Mang, const TargetMachine &TM) const {}
78 /// Given a constant with the SectionKind, return a section that it should be
80 virtual const MCSection *getSectionForConstant(SectionKind Kind,
81 const Constant *C) const;
83 /// Classify the specified global variable into a set of target independent
84 /// categories embodied in SectionKind.
85 static SectionKind getKindForGlobal(const GlobalValue *GV,
86 const TargetMachine &TM);
88 /// This method computes the appropriate section to emit the specified global
89 /// variable or function definition. This should not be passed external (or
90 /// available externally) globals.
91 const MCSection *SectionForGlobal(const GlobalValue *GV,
92 SectionKind Kind, Mangler &Mang,
93 const TargetMachine &TM) const;
95 /// This method computes the appropriate section to emit the specified global
96 /// variable or function definition. This should not be passed external (or
97 /// available externally) globals.
98 const MCSection *SectionForGlobal(const GlobalValue *GV,
100 const TargetMachine &TM) const {
101 return SectionForGlobal(GV, getKindForGlobal(GV, TM), Mang, TM);
104 virtual void getNameWithPrefix(SmallVectorImpl<char> &OutName,
105 const GlobalValue *GV,
106 bool CannotUsePrivateLabel, Mangler &Mang,
107 const TargetMachine &TM) const;
109 virtual const MCSection *
110 getSectionForJumpTable(const Function &F, Mangler &Mang,
111 const TargetMachine &TM) const;
113 virtual bool shouldPutJumpTableInFunctionSection(bool UsesLabelDifference,
114 const Function &F) const;
116 /// Targets should implement this method to assign a section to globals with
117 /// an explicit section specfied. The implementation of this method can
118 /// assume that GV->hasSection() is true.
119 virtual const MCSection *
120 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
121 Mangler &Mang, const TargetMachine &TM) const = 0;
123 /// Allow the target to completely override section assignment of a global.
124 virtual const MCSection *getSpecialCasedSectionGlobals(const GlobalValue *GV,
126 Mangler &Mang) const {
130 /// Return an MCExpr to use for a reference to the specified global variable
131 /// from exception handling information.
132 virtual const MCExpr *
133 getTTypeGlobalReference(const GlobalValue *GV, unsigned Encoding,
134 Mangler &Mang, const TargetMachine &TM,
135 MachineModuleInfo *MMI, MCStreamer &Streamer) const;
137 /// Return the MCSymbol for a private symbol with global value name as its
138 /// base, with the specified suffix.
139 MCSymbol *getSymbolWithGlobalValueBase(const GlobalValue *GV,
140 StringRef Suffix, Mangler &Mang,
141 const TargetMachine &TM) const;
143 // The symbol that gets passed to .cfi_personality.
144 virtual MCSymbol *getCFIPersonalitySymbol(const GlobalValue *GV,
146 const TargetMachine &TM,
147 MachineModuleInfo *MMI) const;
150 getTTypeReference(const MCSymbolRefExpr *Sym, unsigned Encoding,
151 MCStreamer &Streamer) const;
153 virtual const MCSection *getStaticCtorSection(unsigned Priority,
154 const MCSymbol *KeySym) const {
155 return StaticCtorSection;
158 virtual const MCSection *getStaticDtorSection(unsigned Priority,
159 const MCSymbol *KeySym) const {
160 return StaticDtorSection;
163 /// \brief Create a symbol reference to describe the given TLS variable when
164 /// emitting the address in debug info.
165 virtual const MCExpr *getDebugThreadLocalSymbol(const MCSymbol *Sym) const;
167 virtual const MCExpr *
168 getExecutableRelativeSymbol(const ConstantExpr *CE, Mangler &Mang,
169 const TargetMachine &TM) const {
173 /// \brief Target supports replacing a data "PC"-relative access to a symbol
174 /// through another symbol, by accessing the later via a GOT entry instead?
175 bool supportIndirectSymViaGOTPCRel() const {
176 return SupportIndirectSymViaGOTPCRel;
179 /// \brief Target GOT "PC"-relative relocation supports encoding an additional
180 /// binary expression with an offset?
181 bool supportGOTPCRelWithOffset() const {
182 return SupportGOTPCRelWithOffset;
185 /// \brief Get the target specific PC relative GOT entry relocation
186 virtual const MCExpr *getIndirectSymViaGOTPCRel(const MCSymbol *Sym,
189 MachineModuleInfo *MMI,
190 MCStreamer &Streamer) const {
195 virtual const MCSection *
196 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
197 Mangler &Mang, const TargetMachine &TM) const = 0;
200 } // end namespace llvm