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ARMAsmBackend.h
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1 //===-- ARMAsmBackend.h - ARM Assembler Backend -----------------*- 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 #ifndef LLVM_LIB_TARGET_ARM_ARMASMBACKEND_H
10 #define LLVM_LIB_TARGET_ARM_ARMASMBACKEND_H
11 
14 #include "llvm/MC/MCAsmBackend.h"
17 
18 namespace llvm {
19 
20 class ARMAsmBackend : public MCAsmBackend {
21  // The STI from the target triple the MCAsmBackend was instantiated with
22  // note that MCFragments may have a different local STI that should be
23  // used in preference.
24  const MCSubtargetInfo &STI;
25  bool isThumbMode; // Currently emitting Thumb code.
26 public:
27  ARMAsmBackend(const Target &T, const MCSubtargetInfo &STI,
29  : MCAsmBackend(Endian), STI(STI),
30  isThumbMode(STI.getTargetTriple().isThumb()) {}
31 
32  unsigned getNumFixupKinds() const override {
34  }
35 
36  // FIXME: this should be calculated per fragment as the STI may be
37  // different.
38  bool hasNOP() const { return STI.getFeatureBits()[ARM::HasV6T2Ops]; }
39 
40  const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override;
41 
43  const MCValue &Target) override;
44 
45  unsigned adjustFixupValue(const MCAssembler &Asm, const MCFixup &Fixup,
46  const MCValue &Target, uint64_t Value,
47  bool IsResolved, MCContext &Ctx,
48  const MCSubtargetInfo *STI) const;
49 
50  void applyFixup(const MCAssembler &Asm, const MCFixup &Fixup,
51  const MCValue &Target, MutableArrayRef<char> Data,
52  uint64_t Value, bool IsResolved,
53  const MCSubtargetInfo *STI) const override;
54 
55  unsigned getRelaxedOpcode(unsigned Op, const MCSubtargetInfo &STI) const;
56 
57  bool mayNeedRelaxation(const MCInst &Inst,
58  const MCSubtargetInfo &STI) const override;
59 
60  const char *reasonForFixupRelaxation(const MCFixup &Fixup,
61  uint64_t Value) const;
62 
63  bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
64  const MCRelaxableFragment *DF,
65  const MCAsmLayout &Layout) const override;
66 
67  void relaxInstruction(const MCInst &Inst, const MCSubtargetInfo &STI,
68  MCInst &Res) const override;
69 
70  bool writeNopData(raw_ostream &OS, uint64_t Count) const override;
71 
73 
74  unsigned getPointerSize() const { return 4; }
75  bool isThumb() const { return isThumbMode; }
76  void setIsThumb(bool it) { isThumbMode = it; }
77 };
78 } // end namespace llvm
79 
80 #endif
unsigned getNumFixupKinds() const override
Get the number of target specific fixup kinds.
Definition: ARMAsmBackend.h:32
unsigned getRelaxedOpcode(unsigned Op, const MCSubtargetInfo &STI) const
void setIsThumb(bool it)
Definition: ARMAsmBackend.h:76
unsigned getPointerSize() const
Definition: ARMAsmBackend.h:74
This class represents lattice values for constants.
Definition: AllocatorList.h:23
This represents an "assembler immediate".
Definition: MCValue.h:39
const char * reasonForFixupRelaxation(const MCFixup &Fixup, uint64_t Value) const
const support::endianness Endian
Definition: MCAsmBackend.h:52
bool hasNOP() const
Definition: ARMAsmBackend.h:38
Encode information on a single operation to perform on a byte sequence (e.g., an encoded instruction)...
Definition: MCFixup.h:73
const FeatureBitset & getFeatureBits() const
Encapsulates the layout of an assembly file at a particular point in time.
Definition: MCAsmLayout.h:28
Context object for machine code objects.
Definition: MCContext.h:62
ARMAsmBackend(const Target &T, const MCSubtargetInfo &STI, support::endianness Endian)
Definition: ARMAsmBackend.h:27
Instances of this class represent a single low-level machine instruction.
Definition: MCInst.h:158
Flag
These should be considered private to the implementation of the MCInstrDesc class.
Definition: MCInstrDesc.h:117
A relaxable fragment holds on to its MCInst, since it may need to be relaxed during the assembler lay...
Definition: MCFragment.h:270
MutableArrayRef - Represent a mutable reference to an array (0 or more elements consecutively in memo...
Definition: ArrayRef.h:290
bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value, const MCRelaxableFragment *DF, const MCAsmLayout &Layout) const override
Simple predicate for targets where !Resolved implies requiring relaxation.
MCFixupKind
Extensible enumeration to represent the type of a fixup.
Definition: MCFixup.h:22
const MCFixupKindInfo & getFixupKindInfo(MCFixupKind Kind) const override
Get information on a fixup kind.
unsigned adjustFixupValue(const MCAssembler &Asm, const MCFixup &Fixup, const MCValue &Target, uint64_t Value, bool IsResolved, MCContext &Ctx, const MCSubtargetInfo *STI) const
bool writeNopData(raw_ostream &OS, uint64_t Count) const override
Write an (optimal) nop sequence of Count bytes to the given output.
PowerPC TLS Dynamic Call Fixup
void relaxInstruction(const MCInst &Inst, const MCSubtargetInfo &STI, MCInst &Res) const override
Relax the instruction in the given fragment to the next wider instruction.
Target - Wrapper for Target specific information.
void handleAssemblerFlag(MCAssemblerFlag Flag) override
Handle any target-specific assembler flags. By default, do nothing.
MCAssemblerFlag
Definition: MCDirectives.h:48
Generic base class for all target subtargets.
Target independent information on a fixup kind.
bool mayNeedRelaxation(const MCInst &Inst, const MCSubtargetInfo &STI) const override
Check whether the given instruction may need relaxation.
void applyFixup(const MCAssembler &Asm, const MCFixup &Fixup, const MCValue &Target, MutableArrayRef< char > Data, uint64_t Value, bool IsResolved, const MCSubtargetInfo *STI) const override
Apply the Value for given Fixup into the provided data fragment, at the offset specified by the fixup...
LLVM Value Representation.
Definition: Value.h:72
Generic interface to target specific assembler backends.
Definition: MCAsmBackend.h:41
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:45
bool isThumb() const
Definition: ARMAsmBackend.h:75
bool shouldForceRelocation(const MCAssembler &Asm, const MCFixup &Fixup, const MCValue &Target) override
Hook to check if a relocation is needed for some target specific reason.