LLVM  7.0.0svn
TargetLoweringObjectFile.h
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1 //===-- llvm/Target/TargetLoweringObjectFile.h - Object Info ----*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements classes used to handle lowerings specific to common
11 // object file formats.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CODEGEN_TARGETLOWERINGOBJECTFILE_H
16 #define LLVM_CODEGEN_TARGETLOWERINGOBJECTFILE_H
17 
18 #include "llvm/ADT/ArrayRef.h"
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/IR/Module.h"
22 #include "llvm/MC/SectionKind.h"
23 #include <cstdint>
24 
25 namespace llvm {
26 
27 class GlobalValue;
28 class MachineModuleInfo;
29 class Mangler;
30 class MCContext;
31 class MCExpr;
32 class MCSection;
33 class MCSymbol;
34 class MCSymbolRefExpr;
35 class MCStreamer;
36 class MCValue;
37 class TargetMachine;
38 
40  MCContext *Ctx = nullptr;
41 
42  /// Name-mangler for global names.
43  Mangler *Mang = nullptr;
44 
45 protected:
48 
49  /// This section contains the static constructor pointer list.
51 
52  /// This section contains the static destructor pointer list.
54 
55 public:
56  TargetLoweringObjectFile() = default;
59  operator=(const TargetLoweringObjectFile &) = delete;
60  virtual ~TargetLoweringObjectFile();
61 
62  MCContext &getContext() const { return *Ctx; }
63  Mangler &getMangler() const { return *Mang; }
64 
65  /// This method must be called before any actual lowering is done. This
66  /// specifies the current context for codegen, and gives the lowering
67  /// implementations a chance to set up their default sections.
68  virtual void Initialize(MCContext &ctx, const TargetMachine &TM);
69 
70  virtual void emitPersonalityValue(MCStreamer &Streamer, const DataLayout &TM,
71  const MCSymbol *Sym) const;
72 
73  /// Emit the module-level metadata that the platform cares about.
74  virtual void emitModuleMetadata(MCStreamer &Streamer, Module &M) const {}
75 
76  /// Given a constant with the SectionKind, return a section that it should be
77  /// placed in.
78  virtual MCSection *getSectionForConstant(const DataLayout &DL,
80  const Constant *C,
81  unsigned &Align) const;
82 
83  /// Classify the specified global variable into a set of target independent
84  /// categories embodied in SectionKind.
85  static SectionKind getKindForGlobal(const GlobalObject *GO,
86  const TargetMachine &TM);
87 
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.
92  const TargetMachine &TM) const;
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  return SectionForGlobal(GO, getKindForGlobal(GO, TM), TM);
100  }
101 
102  virtual void getNameWithPrefix(SmallVectorImpl<char> &OutName,
103  const GlobalValue *GV,
104  const TargetMachine &TM) const;
105 
106  virtual MCSection *getSectionForJumpTable(const Function &F,
107  const TargetMachine &TM) const;
108 
109  virtual bool shouldPutJumpTableInFunctionSection(bool UsesLabelDifference,
110  const Function &F) const;
111 
112  /// Targets should implement this method to assign a section to globals with
113  /// an explicit section specfied. The implementation of this method can
114  /// assume that GO->hasSection() is true.
115  virtual MCSection *
117  const TargetMachine &TM) const = 0;
118 
119  /// Return an MCExpr to use for a reference to the specified global variable
120  /// from exception handling information.
121  virtual const MCExpr *getTTypeGlobalReference(const GlobalValue *GV,
122  unsigned Encoding,
123  const TargetMachine &TM,
124  MachineModuleInfo *MMI,
125  MCStreamer &Streamer) const;
126 
127  /// Return the MCSymbol for a private symbol with global value name as its
128  /// base, with the specified suffix.
130  StringRef Suffix,
131  const TargetMachine &TM) const;
132 
133  // The symbol that gets passed to .cfi_personality.
134  virtual MCSymbol *getCFIPersonalitySymbol(const GlobalValue *GV,
135  const TargetMachine &TM,
136  MachineModuleInfo *MMI) const;
137 
138  const MCExpr *getTTypeReference(const MCSymbolRefExpr *Sym, unsigned Encoding,
139  MCStreamer &Streamer) const;
140 
141  virtual MCSection *getStaticCtorSection(unsigned Priority,
142  const MCSymbol *KeySym) const {
143  return StaticCtorSection;
144  }
145 
146  virtual MCSection *getStaticDtorSection(unsigned Priority,
147  const MCSymbol *KeySym) const {
148  return StaticDtorSection;
149  }
150 
151  /// Create a symbol reference to describe the given TLS variable when
152  /// emitting the address in debug info.
153  virtual const MCExpr *getDebugThreadLocalSymbol(const MCSymbol *Sym) const;
154 
155  virtual const MCExpr *lowerRelativeReference(const GlobalValue *LHS,
156  const GlobalValue *RHS,
157  const TargetMachine &TM) const {
158  return nullptr;
159  }
160 
161  /// Target supports replacing a data "PC"-relative access to a symbol
162  /// through another symbol, by accessing the later via a GOT entry instead?
165  }
166 
167  /// Target GOT "PC"-relative relocation supports encoding an additional
168  /// binary expression with an offset?
171  }
172 
173  /// Get the target specific PC relative GOT entry relocation
174  virtual const MCExpr *getIndirectSymViaGOTPCRel(const MCSymbol *Sym,
175  const MCValue &MV,
176  int64_t Offset,
177  MachineModuleInfo *MMI,
178  MCStreamer &Streamer) const {
179  return nullptr;
180  }
181 
183  const GlobalValue *GV) const {}
184 
186  const GlobalValue *GV) const {}
187 
188 protected:
189  virtual MCSection *SelectSectionForGlobal(const GlobalObject *GO,
190  SectionKind Kind,
191  const TargetMachine &TM) const = 0;
192 };
193 
194 } // end namespace llvm
195 
196 #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:39
A parsed version of the target data layout string in and methods for querying it. ...
Definition: DataLayout.h:111
constexpr char Align[]
Key for Kernel::Arg::Metadata::mAlign.
virtual MCSection * getStaticCtorSection(unsigned Priority, const MCSymbol *KeySym) const
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
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:40
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:42
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:63
MCSection * StaticCtorSection
This section contains the static constructor pointer list.
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
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:36
Represent a reference to a symbol from inside an expression.
Definition: MCExpr.h:166
Context object for machine code objects.
Definition: MCContext.h:63
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:183
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:42
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:23
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:46
Primary interface to the complete machine description for the target machine.
Definition: TargetMachine.h:59
virtual MCSection * getSectionForJumpTable(const Function &F, const TargetMachine &TM) const
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
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.