1 // Copyright 2013 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef V8_COMPILER_OPERATOR_H_
6 #define V8_COMPILER_OPERATOR_H_
8 #include <ostream> // NOLINT(readability/streams)
10 #include "src/base/flags.h"
11 #include "src/base/functional.h"
18 // An operator represents description of the "computation" of a node in the
19 // compiler IR. A computation takes values (i.e. data) as input and produces
20 // zero or more values as output. The side-effects of a computation must be
21 // captured by additional control and data dependencies which are part of the
23 // Operators are immutable and describe the statically-known parts of a
24 // computation. Thus they can be safely shared by many different nodes in the
25 // IR graph, or even globally between graphs. Operators can have "static
26 // parameters" which are compile-time constant parameters to the operator, such
27 // as the name for a named field access, the ID of a runtime function, etc.
28 // Static parameters are private to the operator and only semantically
29 // meaningful to the operator itself.
30 class Operator : public ZoneObject {
32 typedef uint8_t Opcode;
34 // Properties inform the operator-independent optimizer about legal
35 // transformations for nodes that have this operator.
38 kReducible = 1 << 0, // Participates in strength reduction.
39 kCommutative = 1 << 1, // OP(a, b) == OP(b, a) for all inputs.
40 kAssociative = 1 << 2, // OP(a, OP(b,c)) == OP(OP(a,b), c) for all inputs.
41 kIdempotent = 1 << 3, // OP(a); OP(a) == OP(a).
42 kNoRead = 1 << 4, // Has no scheduling dependency on Effects
43 kNoWrite = 1 << 5, // Does not modify any Effects and thereby
44 // create new scheduling dependencies.
45 kNoThrow = 1 << 6, // Can never generate an exception.
46 kFoldable = kNoRead | kNoWrite,
47 kEliminatable = kNoWrite | kNoThrow,
48 kPure = kNoRead | kNoWrite | kNoThrow | kIdempotent
50 typedef base::Flags<Property, uint8_t> Properties;
53 Operator(Opcode opcode, Properties properties, const char* mnemonic,
54 size_t value_in, size_t effect_in, size_t control_in,
55 size_t value_out, size_t effect_out, size_t control_out);
57 virtual ~Operator() {}
59 // A small integer unique to all instances of a particular kind of operator,
60 // useful for quick matching for specific kinds of operators. For fast access
61 // the opcode is stored directly in the operator object.
62 Opcode opcode() const { return opcode_; }
64 // Returns a constant string representing the mnemonic of the operator,
65 // without the static parameters. Useful for debugging.
66 const char* mnemonic() const { return mnemonic_; }
68 // Check if this operator equals another operator. Equivalent operators can
69 // be merged, and nodes with equivalent operators and equivalent inputs
71 virtual bool Equals(const Operator* that) const {
72 return this->opcode() == that->opcode();
75 // Compute a hashcode to speed up equivalence-set checking.
76 // Equal operators should always have equal hashcodes, and unequal operators
77 // should have unequal hashcodes with high probability.
78 virtual size_t HashCode() const { return base::hash<Opcode>()(opcode()); }
80 // Check whether this operator has the given property.
81 bool HasProperty(Property property) const {
82 return (properties() & property) == property;
85 // Number of data inputs to the operator, for verifying graph structure.
86 // TODO(titzer): convert callers to ValueInputCount();
87 int InputCount() const { return ValueInputCount(); }
89 // Number of data outputs from the operator, for verifying graph structure.
90 // TODO(titzer): convert callers to ValueOutputCount();
91 int OutputCount() const { return ValueOutputCount(); }
93 Properties properties() const { return properties_; }
95 // TODO(titzer): convert return values here to size_t.
96 int ValueInputCount() const { return value_in_; }
97 int EffectInputCount() const { return effect_in_; }
98 int ControlInputCount() const { return control_in_; }
100 int ValueOutputCount() const { return value_out_; }
101 int EffectOutputCount() const { return effect_out_; }
102 int ControlOutputCount() const { return control_out_; }
104 static inline size_t ZeroIfPure(Properties properties) {
105 return (properties & kPure) == kPure ? 0 : 1;
108 // TODO(titzer): API for input and output types, for typechecking graph.
110 // Print the full operator into the given stream, including any
111 // static parameters. Useful for debugging and visualizing the IR.
112 virtual void PrintTo(std::ostream& os) const;
113 friend std::ostream& operator<<(std::ostream& os, const Operator& op);
117 Properties properties_;
118 const char* mnemonic_;
121 uint16_t control_in_;
124 uint8_t control_out_;
126 DISALLOW_COPY_AND_ASSIGN(Operator);
129 DEFINE_OPERATORS_FOR_FLAGS(Operator::Properties)
131 std::ostream& operator<<(std::ostream& os, const Operator& op);
134 // A templatized implementation of Operator that has one static parameter of
136 template <typename T, typename Pred = std::equal_to<T>,
137 typename Hash = base::hash<T>>
138 class Operator1 : public Operator {
140 Operator1(Opcode opcode, Properties properties, const char* mnemonic,
141 size_t value_in, size_t effect_in, size_t control_in,
142 size_t value_out, size_t effect_out, size_t control_out,
143 T parameter, Pred const& pred = Pred(), Hash const& hash = Hash())
144 : Operator(opcode, properties, mnemonic, value_in, effect_in, control_in,
145 value_out, effect_out, control_out),
146 parameter_(parameter),
150 T const& parameter() const { return parameter_; }
152 virtual bool Equals(const Operator* other) const FINAL {
153 if (opcode() != other->opcode()) return false;
154 const Operator1<T>* that = static_cast<const Operator1<T>*>(other);
155 return this->pred_(this->parameter(), that->parameter());
157 virtual size_t HashCode() const FINAL {
158 return base::hash_combine(this->opcode(), this->hash_(this->parameter()));
160 virtual void PrintParameter(std::ostream& os) const {
161 os << "[" << this->parameter() << "]";
165 virtual void PrintTo(std::ostream& os) const FINAL {
177 // Helper to extract parameters from Operator1<*> operator.
178 template <typename T>
179 inline T const& OpParameter(const Operator* op) {
180 return static_cast<const Operator1<T>*>(op)->parameter();
183 } // namespace compiler
184 } // namespace internal
187 #endif // V8_COMPILER_OPERATOR_H_