1 //===-- ARMAsmBackend.h - ARM Assembler Backend -----------------*- 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 #ifndef LLVM_LIB_TARGET_ARM_ARMASMBACKEND_H
11 #define LLVM_LIB_TARGET_ARM_ARMASMBACKEND_H
12 
13 #include "MCTargetDesc/ARMFixupKinds.h"
14 #include "llvm/MC/MCAsmBackend.h"
15 #include "llvm/MC/MCSubtargetInfo.h"
16 
17 using namespace llvm;
18 
19 namespace {
20 
21 class ARMAsmBackend : public MCAsmBackend {
22   const MCSubtargetInfo *STI;
23   bool isThumbMode;    // Currently emitting Thumb code.
24   bool IsLittleEndian; // Big or little endian.
25 public:
ARMAsmBackend(const Target & T,const Triple & TT,bool IsLittle)26   ARMAsmBackend(const Target &T, const Triple &TT, bool IsLittle)
27       : MCAsmBackend(), STI(ARM_MC::createARMMCSubtargetInfo(TT, "", "")),
28         isThumbMode(TT.getArchName().startswith("thumb")),
29         IsLittleEndian(IsLittle) {}
30 
~ARMAsmBackend()31   ~ARMAsmBackend() override { delete STI; }
32 
getNumFixupKinds()33   unsigned getNumFixupKinds() const override {
34     return ARM::NumTargetFixupKinds;
35   }
36 
hasNOP()37   bool hasNOP() const { return STI->getFeatureBits()[ARM::HasV6T2Ops]; }
38 
39   const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override;
40 
41   /// processFixupValue - Target hook to process the literal value of a fixup
42   /// if necessary.
43   void processFixupValue(const MCAssembler &Asm, const MCAsmLayout &Layout,
44                          const MCFixup &Fixup, const MCFragment *DF,
45                          const MCValue &Target, uint64_t &Value,
46                          bool &IsResolved) override;
47 
48   unsigned adjustFixupValue(const MCFixup &Fixup, uint64_t Value, bool IsPCRel,
49                             MCContext *Ctx, bool IsLittleEndian,
50                             bool IsResolved) const;
51 
52   void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
53                   uint64_t Value, bool IsPCRel) const override;
54 
55   unsigned getRelaxedOpcode(unsigned Op) const;
56 
57   bool mayNeedRelaxation(const MCInst &Inst) const override;
58 
59   const char *reasonForFixupRelaxation(const MCFixup &Fixup,
60                                        uint64_t Value) const;
61 
62   bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
63                             const MCRelaxableFragment *DF,
64                             const MCAsmLayout &Layout) const override;
65 
66   void relaxInstruction(const MCInst &Inst, MCInst &Res) const override;
67 
68   bool writeNopData(uint64_t Count, MCObjectWriter *OW) const override;
69 
70   void handleAssemblerFlag(MCAssemblerFlag Flag) override;
71 
getPointerSize()72   unsigned getPointerSize() const { return 4; }
isThumb()73   bool isThumb() const { return isThumbMode; }
setIsThumb(bool it)74   void setIsThumb(bool it) { isThumbMode = it; }
isLittle()75   bool isLittle() const { return IsLittleEndian; }
76 };
77 } // end anonymous namespace
78 
79 #endif
80