lib/Target/Mips/MCTargetDesc/MipsELFStreamer.h

   1 //===- MipsELFStreamer.h - ELF Object Output --------------------*- 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 is a custom MCELFStreamer which allows us to insert some hooks before
  10 // emitting data into an actual object file.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_LIB_TARGET_MIPS_MCTARGETDESC_MIPSELFSTREAMER_H
  15 #define LLVM_LIB_TARGET_MIPS_MCTARGETDESC_MIPSELFSTREAMER_H
  16
  17 #include "MipsOptionRecord.h"
  18 #include "llvm/ADT/SmallVector.h"
  19 #include "llvm/MC/MCELFStreamer.h"
  20 #include <memory>
  21
  22 namespace llvm {
  23
  24 class MCAsmBackend;
  25 class MCCodeEmitter;
  26 class MCContext;
  27 class MCSubtargetInfo;
  28 struct MCDwarfFrameInfo;
  29
  30 class MipsELFStreamer : public MCELFStreamer {
  31   SmallVector<std::unique_ptr<MipsOptionRecord>, 8> MipsOptionRecords;
  32   MipsRegInfoRecord *RegInfoRecord;
  33   SmallVector<MCSymbol*, 4> Labels;
  34
  35 public:
  36   MipsELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> MAB,
  37                   std::unique_ptr<MCObjectWriter> OW,
  38                   std::unique_ptr<MCCodeEmitter> Emitter);
  39
  40   /// Overriding this function allows us to add arbitrary behaviour before the
  41   /// \p Inst is actually emitted. For example, we can inspect the operands and
  42   /// gather sufficient information that allows us to reason about the register
  43   /// usage for the translation unit.
  44   void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI) override;
  45
  46   /// Overriding this function allows us to record all labels that should be
  47   /// marked as microMIPS. Based on this data marking is done in
  48   /// EmitInstruction.
  49   void EmitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc()) override;
  50
  51   /// Overriding this function allows us to dismiss all labels that are
  52   /// candidates for marking as microMIPS when .section directive is processed.
  53   void SwitchSection(MCSection *Section,
  54                      const MCExpr *Subsection = nullptr) override;
  55
  56   /// Overriding these functions allows us to dismiss all labels that are
  57   /// candidates for marking as microMIPS when .word/.long/.4byte etc
  58   /// directives are emitted.
  59   void EmitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override;
  60   void EmitIntValue(uint64_t Value, unsigned Size) override;
  61
  62   // Overriding these functions allows us to avoid recording of these labels
  63   // in EmitLabel and later marking them as microMIPS.
  64   void EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) override;
  65   void EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) override;
  66   MCSymbol *EmitCFILabel() override;
  67
  68   /// Emits all the option records stored up until the point it's called.
  69   void EmitMipsOptionRecords();
  70
  71   /// Mark labels as microMIPS, if necessary for the subtarget.
  72   void createPendingLabelRelocs();
  73 };
  74
  75 MCELFStreamer *createMipsELFStreamer(MCContext &Context,
  76                                      std::unique_ptr<MCAsmBackend> MAB,
  77                                      std::unique_ptr<MCObjectWriter> OW,
  78                                      std::unique_ptr<MCCodeEmitter> Emitter,
  79                                      bool RelaxAll);
  80 } // end namespace llvm
  81
  82 #endif // LLVM_LIB_TARGET_MIPS_MCTARGETDESC_MIPSELFSTREAMER_H