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
83