LLVM  10.0.0svn
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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 //===----------------------------------------------------------------------===//
14 #include "llvm/MC/MCAsmBackend.h"
18 namespace llvm {
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()) {}
32  unsigned getNumFixupKinds() const override {
34  }
36  // FIXME: this should be calculated per fragment as the STI may be
37  // different.
38  bool hasNOP() const { return STI.getFeatureBits()[ARM::HasV6T2Ops]; }
42  const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override;
45  const MCValue &Target) override;
47  unsigned adjustFixupValue(const MCAssembler &Asm, const MCFixup &Fixup,
48  const MCValue &Target, uint64_t Value,
49  bool IsResolved, MCContext &Ctx,
50  const MCSubtargetInfo *STI) const;
52  void applyFixup(const MCAssembler &Asm, const MCFixup &Fixup,
53  const MCValue &Target, MutableArrayRef<char> Data,
54  uint64_t Value, bool IsResolved,
55  const MCSubtargetInfo *STI) const override;
57  unsigned getRelaxedOpcode(unsigned Op, const MCSubtargetInfo &STI) const;
59  bool mayNeedRelaxation(const MCInst &Inst,
60  const MCSubtargetInfo &STI) const override;
62  const char *reasonForFixupRelaxation(const MCFixup &Fixup,
63  uint64_t Value) const;
65  bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
66  const MCRelaxableFragment *DF,
67  const MCAsmLayout &Layout) const override;
69  void relaxInstruction(const MCInst &Inst, const MCSubtargetInfo &STI,
70  MCInst &Res) const override;
72  bool writeNopData(raw_ostream &OS, uint64_t Count) const override;
76  unsigned getPointerSize() const { return 4; }
77  bool isThumb() const { return isThumbMode; }
78  void setIsThumb(bool it) { isThumbMode = it; }
79 };
80 } // end namespace llvm
82 #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:78
unsigned getPointerSize() const
Definition: ARMAsmBackend.h:76
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
amdgpu Simplify well known AMD library false FunctionCallee Value const Twine & Name
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:77
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:65
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
These should be considered private to the implementation of the MCInstrDesc class.
Definition: MCInstrDesc.h:131
A relaxable fragment holds on to its MCInst, since it may need to be relaxed during the assembler lay...
Definition: MCFragment.h:272
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.
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.
Definition: MCDirectives.h:49
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:74
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
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:48
bool isThumb() const
Definition: ARMAsmBackend.h:77
Optional< MCFixupKind > getFixupKind(StringRef Name) const override
Map a relocation name used in .reloc to a fixup kind.
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.