llvm/CodeGen/TargetLoweringObjectFileImpl.h

0001 //==- llvm/CodeGen/TargetLoweringObjectFileImpl.h - Object Info --*- C++ -*-==//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008 //
0009 // This file implements classes used to handle lowerings specific to common
0010 // object file formats.
0011 //
0012 //===----------------------------------------------------------------------===//
0013
0014 #ifndef LLVM_CODEGEN_TARGETLOWERINGOBJECTFILEIMPL_H
0015 #define LLVM_CODEGEN_TARGETLOWERINGOBJECTFILEIMPL_H
0016
0017 #include "llvm/ADT/SmallPtrSet.h"
0018 #include "llvm/BinaryFormat/XCOFF.h"
0019 #include "llvm/MC/MCExpr.h"
0020 #include "llvm/Target/TargetLoweringObjectFile.h"
0021
0022 namespace llvm {
0023
0024 class GlobalValue;
0025 class MachineModuleInfo;
0026 class MachineFunction;
0027 class MCContext;
0028 class MCExpr;
0029 class MCSection;
0030 class MCSymbol;
0031 class Module;
0032 class TargetMachine;
0033
0034 class TargetLoweringObjectFileELF : public TargetLoweringObjectFile {
0035   bool UseInitArray = false;
0036   mutable unsigned NextUniqueID = 1;  // ID 0 is reserved for execute-only sections
0037   SmallPtrSet<GlobalObject *, 2> Used;
0038
0039 protected:
0040   MCSymbolRefExpr::VariantKind PLTRelativeVariantKind =
0041       MCSymbolRefExpr::VK_None;
0042
0043 public:
0044   TargetLoweringObjectFileELF();
0045   ~TargetLoweringObjectFileELF() override = default;
0046
0047   void Initialize(MCContext &Ctx, const TargetMachine &TM) override;
0048
0049   void getModuleMetadata(Module &M) override;
0050
0051   /// Emit Obj-C garbage collection and linker options.
0052   void emitModuleMetadata(MCStreamer &Streamer, Module &M) const override;
0053
0054   void emitPersonalityValue(MCStreamer &Streamer, const DataLayout &DL,
0055                             const MCSymbol *Sym,
0056                             const MachineModuleInfo *MMI) const override;
0057
0058   virtual void emitPersonalityValueImpl(MCStreamer &Streamer,
0059                                         const DataLayout &DL,
0060                                         const MCSymbol *Sym,
0061                                         const MachineModuleInfo *MMI) const;
0062
0063   void emitLinkerDirectives(MCStreamer &Streamer, Module &M) const override;
0064
0065   /// Given a constant with the SectionKind, return a section that it should be
0066   /// placed in.
0067   MCSection *getSectionForConstant(const DataLayout &DL, SectionKind Kind,
0068                                    const Constant *C,
0069                                    Align &Alignment) const override;
0070
0071   MCSection *getExplicitSectionGlobal(const GlobalObject *GO, SectionKind Kind,
0072                                       const TargetMachine &TM) const override;
0073
0074   MCSection *SelectSectionForGlobal(const GlobalObject *GO, SectionKind Kind,
0075                                     const TargetMachine &TM) const override;
0076
0077   MCSection *getSectionForJumpTable(const Function &F,
0078                                     const TargetMachine &TM) const override;
0079   MCSection *getSectionForLSDA(const Function &F, const MCSymbol &FnSym,
0080                                const TargetMachine &TM) const override;
0081
0082   MCSection *
0083   getSectionForMachineBasicBlock(const Function &F,
0084                                  const MachineBasicBlock &MBB,
0085                                  const TargetMachine &TM) const override;
0086
0087   MCSection *
0088   getUniqueSectionForFunction(const Function &F,
0089                               const TargetMachine &TM) const override;
0090
0091   bool shouldPutJumpTableInFunctionSection(bool UsesLabelDifference,
0092                                            const Function &F) const override;
0093
0094   /// Return an MCExpr to use for a reference to the specified type info global
0095   /// variable from exception handling information.
0096   const MCExpr *getTTypeGlobalReference(const GlobalValue *GV,
0097                                         unsigned Encoding,
0098                                         const TargetMachine &TM,
0099                                         MachineModuleInfo *MMI,
0100                                         MCStreamer &Streamer) const override;
0101
0102   // The symbol that gets passed to .cfi_personality.
0103   MCSymbol *getCFIPersonalitySymbol(const GlobalValue *GV,
0104                                     const TargetMachine &TM,
0105                                     MachineModuleInfo *MMI) const override;
0106
0107   void InitializeELF(bool UseInitArray_);
0108   MCSection *getStaticCtorSection(unsigned Priority,
0109                                   const MCSymbol *KeySym) const override;
0110   MCSection *getStaticDtorSection(unsigned Priority,
0111                                   const MCSymbol *KeySym) const override;
0112
0113   const MCExpr *lowerRelativeReference(const GlobalValue *LHS,
0114                                        const GlobalValue *RHS,
0115                                        const TargetMachine &TM) const override;
0116
0117   const MCExpr *lowerDSOLocalEquivalent(const DSOLocalEquivalent *Equiv,
0118                                         const TargetMachine &TM) const override;
0119
0120   MCSection *getSectionForCommandLines() const override;
0121 };
0122
0123 class TargetLoweringObjectFileMachO : public TargetLoweringObjectFile {
0124 public:
0125   TargetLoweringObjectFileMachO();
0126   ~TargetLoweringObjectFileMachO() override = default;
0127
0128   void Initialize(MCContext &Ctx, const TargetMachine &TM) override;
0129
0130   MCSection *getStaticDtorSection(unsigned Priority,
0131                                   const MCSymbol *KeySym) const override;
0132
0133   /// Emit the module flags that specify the garbage collection information.
0134   void emitModuleMetadata(MCStreamer &Streamer, Module &M) const override;
0135
0136   void emitLinkerDirectives(MCStreamer &Streamer, Module &M) const override;
0137
0138   MCSection *SelectSectionForGlobal(const GlobalObject *GO, SectionKind Kind,
0139                                     const TargetMachine &TM) const override;
0140
0141   MCSection *getExplicitSectionGlobal(const GlobalObject *GO, SectionKind Kind,
0142                                       const TargetMachine &TM) const override;
0143
0144   MCSection *getSectionForConstant(const DataLayout &DL, SectionKind Kind,
0145                                    const Constant *C,
0146                                    Align &Alignment) const override;
0147
0148   /// The mach-o version of this method defaults to returning a stub reference.
0149   const MCExpr *getTTypeGlobalReference(const GlobalValue *GV,
0150                                         unsigned Encoding,
0151                                         const TargetMachine &TM,
0152                                         MachineModuleInfo *MMI,
0153                                         MCStreamer &Streamer) const override;
0154
0155   // The symbol that gets passed to .cfi_personality.
0156   MCSymbol *getCFIPersonalitySymbol(const GlobalValue *GV,
0157                                     const TargetMachine &TM,
0158                                     MachineModuleInfo *MMI) const override;
0159
0160   /// Get MachO PC relative GOT entry relocation
0161   const MCExpr *getIndirectSymViaGOTPCRel(const GlobalValue *GV,
0162                                           const MCSymbol *Sym,
0163                                           const MCValue &MV, int64_t Offset,
0164                                           MachineModuleInfo *MMI,
0165                                           MCStreamer &Streamer) const override;
0166
0167   void getNameWithPrefix(SmallVectorImpl<char> &OutName, const GlobalValue *GV,
0168                          const TargetMachine &TM) const override;
0169
0170   MCSection *getSectionForCommandLines() const override;
0171 };
0172
0173 class TargetLoweringObjectFileCOFF : public TargetLoweringObjectFile {
0174   mutable unsigned NextUniqueID = 0;
0175   const TargetMachine *TM = nullptr;
0176
0177 public:
0178   ~TargetLoweringObjectFileCOFF() override = default;
0179
0180   void Initialize(MCContext &Ctx, const TargetMachine &TM) override;
0181   MCSection *getExplicitSectionGlobal(const GlobalObject *GO, SectionKind Kind,
0182                                       const TargetMachine &TM) const override;
0183
0184   MCSection *SelectSectionForGlobal(const GlobalObject *GO, SectionKind Kind,
0185                                     const TargetMachine &TM) const override;
0186
0187   void getNameWithPrefix(SmallVectorImpl<char> &OutName, const GlobalValue *GV,
0188                          const TargetMachine &TM) const override;
0189
0190   MCSection *getSectionForJumpTable(const Function &F,
0191                                     const TargetMachine &TM) const override;
0192
0193   bool shouldPutJumpTableInFunctionSection(bool UsesLabelDifference,
0194                                            const Function &F) const override;
0195
0196   /// Emit Obj-C garbage collection and linker options.
0197   void emitModuleMetadata(MCStreamer &Streamer, Module &M) const override;
0198
0199   void emitLinkerDirectives(MCStreamer &Streamer, Module &M) const override;
0200
0201   MCSection *getStaticCtorSection(unsigned Priority,
0202                                   const MCSymbol *KeySym) const override;
0203   MCSection *getStaticDtorSection(unsigned Priority,
0204                                   const MCSymbol *KeySym) const override;
0205
0206   const MCExpr *lowerRelativeReference(const GlobalValue *LHS,
0207                                        const GlobalValue *RHS,
0208                                        const TargetMachine &TM) const override;
0209
0210   /// Given a mergeable constant with the specified size and relocation
0211   /// information, return a section that it should be placed in.
0212   MCSection *getSectionForConstant(const DataLayout &DL, SectionKind Kind,
0213                                    const Constant *C,
0214                                    Align &Alignment) const override;
0215 };
0216
0217 class TargetLoweringObjectFileWasm : public TargetLoweringObjectFile {
0218   mutable unsigned NextUniqueID = 0;
0219   SmallPtrSet<GlobalObject *, 2> Used;
0220
0221 public:
0222   TargetLoweringObjectFileWasm() = default;
0223   ~TargetLoweringObjectFileWasm() override = default;
0224
0225   void getModuleMetadata(Module &M) override;
0226
0227   MCSection *getExplicitSectionGlobal(const GlobalObject *GO, SectionKind Kind,
0228                                       const TargetMachine &TM) const override;
0229
0230   MCSection *SelectSectionForGlobal(const GlobalObject *GO, SectionKind Kind,
0231                                     const TargetMachine &TM) const override;
0232
0233   bool shouldPutJumpTableInFunctionSection(bool UsesLabelDifference,
0234                                            const Function &F) const override;
0235
0236   void InitializeWasm();
0237   MCSection *getStaticCtorSection(unsigned Priority,
0238                                   const MCSymbol *KeySym) const override;
0239   MCSection *getStaticDtorSection(unsigned Priority,
0240                                   const MCSymbol *KeySym) const override;
0241
0242   const MCExpr *lowerRelativeReference(const GlobalValue *LHS,
0243                                        const GlobalValue *RHS,
0244                                        const TargetMachine &TM) const override;
0245 };
0246
0247 class TargetLoweringObjectFileXCOFF : public TargetLoweringObjectFile {
0248 public:
0249   TargetLoweringObjectFileXCOFF() = default;
0250   ~TargetLoweringObjectFileXCOFF() override = default;
0251
0252   static bool ShouldEmitEHBlock(const MachineFunction *MF);
0253   static bool ShouldSetSSPCanaryBitInTB(const MachineFunction *MF);
0254
0255   static MCSymbol *getEHInfoTableSymbol(const MachineFunction *MF);
0256
0257   void Initialize(MCContext &Ctx, const TargetMachine &TM) override;
0258
0259   bool shouldPutJumpTableInFunctionSection(bool UsesLabelDifference,
0260                                            const Function &F) const override;
0261
0262   MCSection *getExplicitSectionGlobal(const GlobalObject *GO, SectionKind Kind,
0263                                       const TargetMachine &TM) const override;
0264
0265   MCSection *getStaticCtorSection(unsigned Priority,
0266                                   const MCSymbol *KeySym) const override;
0267   MCSection *getStaticDtorSection(unsigned Priority,
0268                                   const MCSymbol *KeySym) const override;
0269
0270   const MCExpr *lowerRelativeReference(const GlobalValue *LHS,
0271                                        const GlobalValue *RHS,
0272                                        const TargetMachine &TM) const override;
0273
0274   MCSection *SelectSectionForGlobal(const GlobalObject *GO, SectionKind Kind,
0275                                     const TargetMachine &TM) const override;
0276
0277   MCSection *getSectionForJumpTable(const Function &F,
0278                                     const TargetMachine &TM) const override;
0279
0280   /// Given a constant with the SectionKind, return a section that it should be
0281   /// placed in.
0282   MCSection *getSectionForConstant(const DataLayout &DL, SectionKind Kind,
0283                                    const Constant *C,
0284                                    Align &Alignment) const override;
0285
0286   static XCOFF::StorageClass getStorageClassForGlobal(const GlobalValue *GV);
0287
0288   MCSection *
0289   getSectionForFunctionDescriptor(const Function *F,
0290                                   const TargetMachine &TM) const override;
0291   MCSection *getSectionForTOCEntry(const MCSymbol *Sym,
0292                                    const TargetMachine &TM) const override;
0293
0294   /// For external functions, this will always return a function descriptor
0295   /// csect.
0296   MCSection *
0297   getSectionForExternalReference(const GlobalObject *GO,
0298                                  const TargetMachine &TM) const override;
0299
0300   /// For functions, this will always return a function descriptor symbol.
0301   MCSymbol *getTargetSymbol(const GlobalValue *GV,
0302                             const TargetMachine &TM) const override;
0303
0304   MCSymbol *getFunctionEntryPointSymbol(const GlobalValue *Func,
0305                                         const TargetMachine &TM) const override;
0306
0307   /// For functions, this will return the LSDA section. If option
0308   /// -ffunction-sections is on, this will return a unique csect with the
0309   /// function name appended to .gcc_except_table as a suffix of the LSDA
0310   /// section name.
0311   MCSection *getSectionForLSDA(const Function &F, const MCSymbol &FnSym,
0312                                const TargetMachine &TM) const override;
0313 };
0314
0315 class TargetLoweringObjectFileGOFF : public TargetLoweringObjectFile {
0316 public:
0317   TargetLoweringObjectFileGOFF();
0318   ~TargetLoweringObjectFileGOFF() override = default;
0319
0320   MCSection *SelectSectionForGlobal(const GlobalObject *GO, SectionKind Kind,
0321                                     const TargetMachine &TM) const override;
0322   MCSection *getExplicitSectionGlobal(const GlobalObject *GO, SectionKind Kind,
0323                                       const TargetMachine &TM) const override;
0324   MCSection *getSectionForLSDA(const Function &F, const MCSymbol &FnSym,
0325                                const TargetMachine &TM) const override;
0326 };
0327
0328 } // end namespace llvm
0329
0330 #endif // LLVM_CODEGEN_TARGETLOWERINGOBJECTFILEIMPL_H