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