1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
|
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_UTILS_TABLEGEN_COMMON_INSTRUCTIONENCODING_H
#define LLVM_UTILS_TABLEGEN_COMMON_INSTRUCTIONENCODING_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/KnownBits.h"
#include <optional>
#include <string>
#include <vector>
namespace llvm {
class BitsInit;
class CodeGenInstruction;
class CodeGenTarget;
class Record;
class RecordVal;
class VarLenInst;
// Represents a span of bits in the instruction encoding that's based on a span
// of bits in an operand's encoding.
//
// Width is the width of the span.
// Base is the starting position of that span in the instruction encoding.
// Offset if the starting position of that span in the operand's encoding.
// That is, bits {Base + Width - 1, Base} in the instruction encoding form
// bits {Offset + Width - 1, Offset} in the operands encoding.
struct EncodingField {
unsigned Base, Width, Offset;
EncodingField(unsigned B, unsigned W, unsigned O)
: Base(B), Width(W), Offset(O) {}
};
struct OperandInfo {
StringRef Name;
bool HasNoEncoding = false;
std::vector<EncodingField> Fields;
std::string Decoder;
bool HasCompleteDecoder;
std::optional<uint64_t> InitValue;
OperandInfo(std::string D, bool HCD) : Decoder(D), HasCompleteDecoder(HCD) {}
void addField(unsigned Base, unsigned Width, unsigned Offset) {
Fields.emplace_back(Base, Width, Offset);
}
ArrayRef<EncodingField> fields() const { return Fields; }
};
/// Represents a parsed InstructionEncoding record or a record derived from it.
class InstructionEncoding {
/// The Record this encoding originates from.
const Record *EncodingDef;
/// The instruction this encoding is for.
const CodeGenInstruction *Inst;
/// The name of this encoding (for debugging purposes).
std::string Name;
/// The namespace in which this encoding exists.
StringRef DecoderNamespace;
/// Known bits of this encoding. This is the value of the `Inst` field
/// with any variable references replaced with '?'.
KnownBits InstBits;
/// Mask of bits that should be considered unknown during decoding.
/// This is the value of the `SoftFail` field.
APInt SoftFailMask;
/// The name of the function to use for decoding. May be an empty string,
/// meaning the decoder is generated.
StringRef DecoderMethod;
/// Whether the custom decoding function always succeeds. If a custom decoder
/// function is specified, the value is taken from the target description,
/// otherwise it is inferred.
bool HasCompleteDecoder;
/// Information about the operands' contribution to this encoding.
SmallVector<OperandInfo, 16> Operands;
public:
InstructionEncoding(const Record *EncodingDef,
const CodeGenInstruction *Inst);
/// Returns the Record this encoding originates from.
const Record *getRecord() const { return EncodingDef; }
/// Returns the instruction this encoding is for.
const CodeGenInstruction *getInstruction() const { return Inst; }
/// Returns the name of this encoding, for debugging purposes.
StringRef getName() const { return Name; }
/// Returns the namespace in which this encoding exists.
StringRef getDecoderNamespace() const { return DecoderNamespace; }
/// Returns the size of this encoding, in bits.
unsigned getBitWidth() const { return InstBits.getBitWidth(); }
/// Returns the known bits of this encoding.
const KnownBits &getInstBits() const { return InstBits; }
/// Returns a mask of bits that should be considered unknown during decoding.
const APInt &getSoftFailMask() const { return SoftFailMask; }
/// Returns the known bits of this encoding that must match for
/// successful decoding.
KnownBits getMandatoryBits() const {
KnownBits EncodingBits = InstBits;
// Mark all bits that are allowed to change according to SoftFail mask
// as unknown.
EncodingBits.Zero &= ~SoftFailMask;
EncodingBits.One &= ~SoftFailMask;
return EncodingBits;
}
/// Returns the name of the function to use for decoding, or an empty string
/// if the decoder is generated.
StringRef getDecoderMethod() const { return DecoderMethod; }
/// Returns whether the decoder (either generated or specified by the user)
/// always succeeds.
bool hasCompleteDecoder() const { return HasCompleteDecoder; }
/// Returns information about the operands' contribution to this encoding.
ArrayRef<OperandInfo> getOperands() const { return Operands; }
/// \returns the effective value of the DecoderMethod field. If DecoderMethod
/// is an explictly set value, return false for second.
static std::pair<std::string, bool>
findOperandDecoderMethod(const Record *Record);
static OperandInfo getOpInfo(const Record *TypeRecord);
private:
void parseVarLenEncoding(const VarLenInst &VLI);
void parseFixedLenEncoding(const BitsInit &RecordInstBits);
void parseVarLenOperands(const VarLenInst &VLI);
void parseFixedLenOperands(const BitsInit &Bits);
};
} // namespace llvm
#endif // LLVM_UTILS_TABLEGEN_COMMON_INSTRUCTIONENCODING_H
|
