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RISCVAsmBackend.h
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1 //===-- RISCVAsmBackend.h - RISCV Assembler Backend -----------------------===//
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_RISCV_MCTARGETDESC_RISCVASMBACKEND_H
10 #define LLVM_LIB_TARGET_RISCV_MCTARGETDESC_RISCVASMBACKEND_H
11 
14 #include "Utils/RISCVBaseInfo.h"
15 #include "llvm/MC/MCAsmBackend.h"
18 
19 namespace llvm {
20 class MCAssembler;
21 class MCObjectTargetWriter;
22 class raw_ostream;
23 
24 class RISCVAsmBackend : public MCAsmBackend {
25  const MCSubtargetInfo &STI;
26  uint8_t OSABI;
27  bool Is64Bit;
28  bool ForceRelocs = false;
31 
32 public:
33  RISCVAsmBackend(const MCSubtargetInfo &STI, uint8_t OSABI, bool Is64Bit,
34  const MCTargetOptions &Options)
35  : MCAsmBackend(support::little), STI(STI), OSABI(OSABI), Is64Bit(Is64Bit),
36  TargetOptions(Options) {
37  TargetABI = RISCVABI::computeTargetABI(
38  STI.getTargetTriple(), STI.getFeatureBits(), Options.getABIName());
40  }
41  ~RISCVAsmBackend() override {}
42 
43  void setForceRelocs() { ForceRelocs = true; }
44 
45  // Returns true if relocations will be forced for shouldForceRelocation by
46  // default. This will be true if relaxation is enabled or had previously
47  // been enabled.
48  bool willForceRelocations() const {
49  return ForceRelocs || STI.getFeatureBits()[RISCV::FeatureRelax];
50  }
51 
52  // Generate diff expression relocations if the relax feature is enabled or had
53  // previously been enabled, otherwise it is safe for the assembler to
54  // calculate these internally.
55  bool requiresDiffExpressionRelocations() const override {
56  return willForceRelocations();
57  }
58 
59  // Return Size with extra Nop Bytes for alignment directive in code section.
61  unsigned &Size) override;
62 
63  // Insert target specific fixup type for alignment directive in code section.
65  const MCAsmLayout &Layout,
66  MCAlignFragment &AF) override;
67 
68  bool evaluateTargetFixup(const MCAssembler &Asm, const MCAsmLayout &Layout,
69  const MCFixup &Fixup, const MCFragment *DF,
70  const MCValue &Target, uint64_t &Value,
71  bool &WasForced) override;
72 
73  void applyFixup(const MCAssembler &Asm, const MCFixup &Fixup,
74  const MCValue &Target, MutableArrayRef<char> Data,
75  uint64_t Value, bool IsResolved,
76  const MCSubtargetInfo *STI) const override;
77 
78  std::unique_ptr<MCObjectTargetWriter>
79  createObjectTargetWriter() const override;
80 
81  bool shouldForceRelocation(const MCAssembler &Asm, const MCFixup &Fixup,
82  const MCValue &Target) override;
83 
84  bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
85  const MCRelaxableFragment *DF,
86  const MCAsmLayout &Layout) const override {
87  llvm_unreachable("Handled by fixupNeedsRelaxationAdvanced");
88  }
89 
90  bool fixupNeedsRelaxationAdvanced(const MCFixup &Fixup, bool Resolved,
91  uint64_t Value,
92  const MCRelaxableFragment *DF,
93  const MCAsmLayout &Layout,
94  const bool WasForced) const override;
95 
96  unsigned getNumFixupKinds() const override {
98  }
99 
101 
102  const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override;
103 
104  bool mayNeedRelaxation(const MCInst &Inst,
105  const MCSubtargetInfo &STI) const override;
106  unsigned getRelaxedOpcode(unsigned Op) const;
107 
108  void relaxInstruction(MCInst &Inst,
109  const MCSubtargetInfo &STI) const override;
110 
111  bool writeNopData(raw_ostream &OS, uint64_t Count) const override;
112 
113  const MCTargetOptions &getTargetOptions() const { return TargetOptions; }
114  RISCVABI::ABI getTargetABI() const { return TargetABI; }
115 };
116 }
117 
118 #endif
unsigned getNumFixupKinds() const override
Get the number of target specific fixup kinds.
This class represents lattice values for constants.
Definition: AllocatorList.h:23
This represents an "assembler immediate".
Definition: MCValue.h:37
amdgpu Simplify well known AMD library false FunctionCallee Value const Twine & Name
bool fixupNeedsRelaxationAdvanced(const MCFixup &Fixup, bool Resolved, uint64_t Value, const MCRelaxableFragment *DF, const MCAsmLayout &Layout, const bool WasForced) const override
Target specific predicate for whether a given fixup requires the associated instruction to be relaxed...
Encode information on a single operation to perform on a byte sequence (e.g., an encoded instruction)...
Definition: MCFixup.h:82
const Triple & getTargetTriple() const
RISCVABI::ABI getTargetABI() const
const FeatureBitset & getFeatureBits() const
Encapsulates the layout of an assembly file at a particular point in time.
Definition: MCAsmLayout.h:28
const MCFixupKindInfo & getFixupKindInfo(MCFixupKind Kind) const override
Get information on a fixup kind.
bool willForceRelocations() const
bool shouldInsertExtraNopBytesForCodeAlign(const MCAlignFragment &AF, unsigned &Size) override
Hook to check if extra nop bytes must be inserted for alignment directive.
unsigned getRelaxedOpcode(unsigned Op) const
bool writeNopData(raw_ostream &OS, uint64_t Count) const override
Write an (optimal) nop sequence of Count bytes to the given output.
bool evaluateTargetFixup(const MCAssembler &Asm, const MCAsmLayout &Layout, const MCFixup &Fixup, const MCFragment *DF, const MCValue &Target, uint64_t &Value, bool &WasForced) override
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...
Instances of this class represent a single low-level machine instruction.
Definition: MCInst.h:158
A relaxable fragment holds on to its MCInst, since it may need to be relaxed during the assembler lay...
Definition: MCFragment.h:261
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.
MutableArrayRef - Represent a mutable reference to an array (0 or more elements consecutively in memo...
Definition: ArrayRef.h:298
bool shouldInsertFixupForCodeAlign(MCAssembler &Asm, const MCAsmLayout &Layout, MCAlignFragment &AF) override
Hook which indicates if the target requires a fixup to be generated when handling an align directive ...
MCFixupKind
Extensible enumeration to represent the type of a fixup.
Definition: MCFixup.h:22
std::unique_ptr< MCObjectTargetWriter > createObjectTargetWriter() const override
const MCTargetOptions & getTargetOptions() const
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
static RegisterPass< DebugifyFunctionPass > DF("debugify-function", "Attach debug info to a function")
PowerPC TLS Dynamic Call Fixup
void relaxInstruction(MCInst &Inst, const MCSubtargetInfo &STI) const override
Relax the instruction in the given fragment to the next wider instruction.
Target - Wrapper for Target specific information.
Optional< MCFixupKind > getFixupKind(StringRef Name) const override
Map a relocation name used in .reloc to a fixup kind.
bool requiresDiffExpressionRelocations() const override
Check whether the given target requires emitting differences of two symbols as a set of relocations...
StringRef getABIName() const
getABIName - If this returns a non-empty string this represents the textual name of the ABI that we w...
Generic base class for all target subtargets.
uint32_t Size
Definition: Profile.cpp:46
ABI computeTargetABI(const Triple &TT, FeatureBitset FeatureBits, StringRef ABIName)
Target independent information on a fixup kind.
LLVM Value Representation.
Definition: Value.h:74
Generic interface to target specific assembler backends.
Definition: MCAsmBackend.h:36
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:46
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:57
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.
bool mayNeedRelaxation(const MCInst &Inst, const MCSubtargetInfo &STI) const override
Check whether the given instruction may need relaxation.
RISCVAsmBackend(const MCSubtargetInfo &STI, uint8_t OSABI, bool Is64Bit, const MCTargetOptions &Options)
void validate(const Triple &TT, const FeatureBitset &FeatureBits)