LLVM  9.0.0svn
TargetLoweringObjectFile.h
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1 //===-- llvm/Target/TargetLoweringObjectFile.h - Object Info ----*- 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 implements classes used to handle lowerings specific to common
10 // object file formats.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CODEGEN_TARGETLOWERINGOBJECTFILE_H
15 #define LLVM_CODEGEN_TARGETLOWERINGOBJECTFILE_H
16 
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/IR/Module.h"
21 #include "llvm/MC/SectionKind.h"
22 #include <cstdint>
23 
24 namespace llvm {
25 
26 class GlobalValue;
27 class MachineModuleInfo;
28 class Mangler;
29 class MCContext;
30 class MCExpr;
31 class MCSection;
32 class MCSymbol;
33 class MCSymbolRefExpr;
34 class MCStreamer;
35 class MCValue;
36 class TargetMachine;
37 
39  MCContext *Ctx = nullptr;
40 
41  /// Name-mangler for global names.
42  Mangler *Mang = nullptr;
43 
44 protected:
48 
49  /// PersonalityEncoding, LSDAEncoding, TTypeEncoding - Some encoding values
50  /// for EH.
51  unsigned PersonalityEncoding = 0;
52  unsigned LSDAEncoding = 0;
53  unsigned TTypeEncoding = 0;
54 
55  /// This section contains the static constructor pointer list.
57 
58  /// This section contains the static destructor pointer list.
60 
61 public:
62  TargetLoweringObjectFile() = default;
65  operator=(const TargetLoweringObjectFile &) = delete;
66  virtual ~TargetLoweringObjectFile();
67 
68  MCContext &getContext() const { return *Ctx; }
69  Mangler &getMangler() const { return *Mang; }
70 
71  /// This method must be called before any actual lowering is done. This
72  /// specifies the current context for codegen, and gives the lowering
73  /// implementations a chance to set up their default sections.
74  virtual void Initialize(MCContext &ctx, const TargetMachine &TM);
75 
76  virtual void emitPersonalityValue(MCStreamer &Streamer, const DataLayout &TM,
77  const MCSymbol *Sym) const;
78 
79  /// Emit the module-level metadata that the platform cares about.
80  virtual void emitModuleMetadata(MCStreamer &Streamer, Module &M) const {}
81 
82  /// Given a constant with the SectionKind, return a section that it should be
83  /// placed in.
84  virtual MCSection *getSectionForConstant(const DataLayout &DL,
86  const Constant *C,
87  unsigned &Align) const;
88 
89  /// Classify the specified global variable into a set of target independent
90  /// categories embodied in SectionKind.
91  static SectionKind getKindForGlobal(const GlobalObject *GO,
92  const TargetMachine &TM);
93 
94  /// This method computes the appropriate section to emit the specified global
95  /// variable or function definition. This should not be passed external (or
96  /// available externally) globals.
98  const TargetMachine &TM) const;
99 
100  /// This method computes the appropriate section to emit the specified global
101  /// variable or function definition. This should not be passed external (or
102  /// available externally) globals.
104  const TargetMachine &TM) const {
105  return SectionForGlobal(GO, getKindForGlobal(GO, TM), TM);
106  }
107 
108  virtual void getNameWithPrefix(SmallVectorImpl<char> &OutName,
109  const GlobalValue *GV,
110  const TargetMachine &TM) const;
111 
112  virtual MCSection *getSectionForJumpTable(const Function &F,
113  const TargetMachine &TM) const;
114 
115  virtual bool shouldPutJumpTableInFunctionSection(bool UsesLabelDifference,
116  const Function &F) const;
117 
118  /// Targets should implement this method to assign a section to globals with
119  /// an explicit section specfied. The implementation of this method can
120  /// assume that GO->hasSection() is true.
121  virtual MCSection *
123  const TargetMachine &TM) const = 0;
124 
125  /// Return an MCExpr to use for a reference to the specified global variable
126  /// from exception handling information.
127  virtual const MCExpr *getTTypeGlobalReference(const GlobalValue *GV,
128  unsigned Encoding,
129  const TargetMachine &TM,
130  MachineModuleInfo *MMI,
131  MCStreamer &Streamer) const;
132 
133  /// Return the MCSymbol for a private symbol with global value name as its
134  /// base, with the specified suffix.
136  StringRef Suffix,
137  const TargetMachine &TM) const;
138 
139  // The symbol that gets passed to .cfi_personality.
140  virtual MCSymbol *getCFIPersonalitySymbol(const GlobalValue *GV,
141  const TargetMachine &TM,
142  MachineModuleInfo *MMI) const;
143 
144  unsigned getPersonalityEncoding() const { return PersonalityEncoding; }
145  unsigned getLSDAEncoding() const { return LSDAEncoding; }
146  unsigned getTTypeEncoding() const { return TTypeEncoding; }
147 
148  const MCExpr *getTTypeReference(const MCSymbolRefExpr *Sym, unsigned Encoding,
149  MCStreamer &Streamer) const;
150 
151  virtual MCSection *getStaticCtorSection(unsigned Priority,
152  const MCSymbol *KeySym) const {
153  return StaticCtorSection;
154  }
155 
156  virtual MCSection *getStaticDtorSection(unsigned Priority,
157  const MCSymbol *KeySym) const {
158  return StaticDtorSection;
159  }
160 
161  /// Create a symbol reference to describe the given TLS variable when
162  /// emitting the address in debug info.
163  virtual const MCExpr *getDebugThreadLocalSymbol(const MCSymbol *Sym) const;
164 
165  virtual const MCExpr *lowerRelativeReference(const GlobalValue *LHS,
166  const GlobalValue *RHS,
167  const TargetMachine &TM) const {
168  return nullptr;
169  }
170 
171  /// Target supports replacing a data "PC"-relative access to a symbol
172  /// through another symbol, by accessing the later via a GOT entry instead?
175  }
176 
177  /// Target GOT "PC"-relative relocation supports encoding an additional
178  /// binary expression with an offset?
181  }
182 
183  /// Target supports TLS offset relocation in debug section?
186  }
187 
188  /// Get the target specific PC relative GOT entry relocation
189  virtual const MCExpr *getIndirectSymViaGOTPCRel(const MCSymbol *Sym,
190  const MCValue &MV,
191  int64_t Offset,
192  MachineModuleInfo *MMI,
193  MCStreamer &Streamer) const {
194  return nullptr;
195  }
196 
198  const GlobalValue *GV) const {}
199 
201  const GlobalValue *GV) const {}
202 
203  /// If supported, return the section to use for the llvm.commandline
204  /// metadata. Otherwise, return nullptr.
206  return nullptr;
207  }
208 
209 protected:
210  virtual MCSection *SelectSectionForGlobal(const GlobalObject *GO,
211  SectionKind Kind,
212  const TargetMachine &TM) const = 0;
213 };
214 
215 } // end namespace llvm
216 
217 #endif // LLVM_CODEGEN_TARGETLOWERINGOBJECTFILE_H
uint64_t CallInst * C
Instances of this class represent a uniqued identifier for a section in the current translation unit...
Definition: MCSection.h:38
A parsed version of the target data layout string in and methods for querying it. ...
Definition: DataLayout.h:110
constexpr char Align[]
Key for Kernel::Arg::Metadata::mAlign.
bool supportDebugThreadLocalLocation() const
Target supports TLS offset relocation in debug section?
virtual MCSection * getStaticCtorSection(unsigned Priority, const MCSymbol *KeySym) const
This class represents lattice values for constants.
Definition: AllocatorList.h:23
virtual void emitPersonalityValue(MCStreamer &Streamer, const DataLayout &TM, const MCSymbol *Sym) const
MCSection * SectionForGlobal(const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const
This method computes the appropriate section to emit the specified global variable or function defini...
This represents an "assembler immediate".
Definition: MCValue.h:39
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:41
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:64
MCSection * StaticCtorSection
This section contains the static constructor pointer list.
virtual MCSection * getSectionForCommandLines() const
If supported, return the section to use for the llvm.commandline metadata.
const MCExpr * getTTypeReference(const MCSymbolRefExpr *Sym, unsigned Encoding, MCStreamer &Streamer) const
F(f)
virtual void emitLinkerFlagsForUsed(raw_ostream &OS, const GlobalValue *GV) const
virtual MCSection * getStaticDtorSection(unsigned Priority, const MCSymbol *KeySym) const
unsigned PersonalityEncoding
PersonalityEncoding, LSDAEncoding, TTypeEncoding - Some encoding values for EH.
virtual void Initialize(MCContext &ctx, const TargetMachine &TM)
This method must be called before any actual lowering is done.
virtual void emitModuleMetadata(MCStreamer &Streamer, Module &M) const
Emit the module-level metadata that the platform cares about.
Base class for the full range of assembler expressions which are needed for parsing.
Definition: MCExpr.h:35
Represent a reference to a symbol from inside an expression.
Definition: MCExpr.h:165
Context object for machine code objects.
Definition: MCContext.h:62
bool supportGOTPCRelWithOffset() const
Target GOT "PC"-relative relocation supports encoding an additional binary expression with an offset...
MCSection * StaticDtorSection
This section contains the static destructor pointer list.
Streaming machine code generation interface.
Definition: MCStreamer.h:188
MCSection * SectionForGlobal(const GlobalObject *GO, const TargetMachine &TM) const
This method computes the appropriate section to emit the specified global variable or function defini...
virtual bool shouldPutJumpTableInFunctionSection(bool UsesLabelDifference, const Function &F) const
virtual void emitLinkerFlagsForGlobal(raw_ostream &OS, const GlobalValue *GV) const
This is an important base class in LLVM.
Definition: Constant.h:41
virtual MCSection * getSectionForConstant(const DataLayout &DL, SectionKind Kind, const Constant *C, unsigned &Align) const
Given a constant with the SectionKind, return a section that it should be placed in.
MCSymbol * getSymbolWithGlobalValueBase(const GlobalValue *GV, StringRef Suffix, const TargetMachine &TM) const
Return the MCSymbol for a private symbol with global value name as its base, with the specified suffi...
SectionKind - This is a simple POD value that classifies the properties of a section.
Definition: SectionKind.h:22
virtual const MCExpr * getTTypeGlobalReference(const GlobalValue *GV, unsigned Encoding, const TargetMachine &TM, MachineModuleInfo *MMI, MCStreamer &Streamer) const
Return an MCExpr to use for a reference to the specified global variable from exception handling info...
virtual const MCExpr * lowerRelativeReference(const GlobalValue *LHS, const GlobalValue *RHS, const TargetMachine &TM) const
virtual const MCExpr * getIndirectSymViaGOTPCRel(const MCSymbol *Sym, const MCValue &MV, int64_t Offset, MachineModuleInfo *MMI, MCStreamer &Streamer) const
Get the target specific PC relative GOT entry relocation.
Module.h This file contains the declarations for the Module class.
TargetLoweringObjectFile & operator=(const TargetLoweringObjectFile &)=delete
virtual void getNameWithPrefix(SmallVectorImpl< char > &OutName, const GlobalValue *GV, const TargetMachine &TM) const
virtual MCSection * getExplicitSectionGlobal(const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const =0
Targets should implement this method to assign a section to globals with an explicit section specfied...
const unsigned Kind
virtual MCSection * SelectSectionForGlobal(const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const =0
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:45
Primary interface to the complete machine description for the target machine.
Definition: TargetMachine.h:58
virtual MCSection * getSectionForJumpTable(const Function &F, const TargetMachine &TM) const
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:48
static SectionKind getKindForGlobal(const GlobalObject *GO, const TargetMachine &TM)
Classify the specified global variable into a set of target independent categories embodied in Sectio...
virtual MCSymbol * getCFIPersonalitySymbol(const GlobalValue *GV, const TargetMachine &TM, MachineModuleInfo *MMI) const
virtual const MCExpr * getDebugThreadLocalSymbol(const MCSymbol *Sym) const
Create a symbol reference to describe the given TLS variable when emitting the address in debug info...
bool supportIndirectSymViaGOTPCRel() const
Target supports replacing a data "PC"-relative access to a symbol through another symbol...
This class contains meta information specific to a module.