1 | /* |
2 | * Copyright 2016 Google Inc. |
3 | * |
4 | * Use of this source code is governed by a BSD-style license that can be |
5 | * found in the LICENSE file. |
6 | */ |
7 | |
8 | #ifndef SKSL_EXPRESSION |
9 | #define SKSL_EXPRESSION |
10 | |
11 | #include "src/sksl/ir/SkSLType.h" |
12 | #include "src/sksl/ir/SkSLVariable.h" |
13 | |
14 | #include <unordered_map> |
15 | |
16 | namespace SkSL { |
17 | |
18 | struct Expression; |
19 | class IRGenerator; |
20 | |
21 | typedef std::unordered_map<const Variable*, std::unique_ptr<Expression>*> DefinitionMap; |
22 | |
23 | /** |
24 | * Abstract supertype of all expressions. |
25 | */ |
26 | struct Expression : public IRNode { |
27 | enum Kind { |
28 | kBinary_Kind, |
29 | kBoolLiteral_Kind, |
30 | kConstructor_Kind, |
31 | kExternalFunctionCall_Kind, |
32 | kExternalValue_Kind, |
33 | kIntLiteral_Kind, |
34 | kFieldAccess_Kind, |
35 | kFloatLiteral_Kind, |
36 | kFunctionReference_Kind, |
37 | kFunctionCall_Kind, |
38 | kIndex_Kind, |
39 | kNullLiteral_Kind, |
40 | kPrefix_Kind, |
41 | kPostfix_Kind, |
42 | kSetting_Kind, |
43 | kSwizzle_Kind, |
44 | kVariableReference_Kind, |
45 | kTernary_Kind, |
46 | kTypeReference_Kind, |
47 | kDefined_Kind |
48 | }; |
49 | |
50 | enum class Property { |
51 | kSideEffects, |
52 | kContainsRTAdjust |
53 | }; |
54 | |
55 | Expression(int offset, Kind kind, const Type& type) |
56 | : INHERITED(offset) |
57 | , fKind(kind) |
58 | , fType(std::move(type)) {} |
59 | |
60 | /** |
61 | * Returns true if this expression is constant. compareConstant must be implemented for all |
62 | * constants! |
63 | */ |
64 | virtual bool isConstant() const { |
65 | return false; |
66 | } |
67 | |
68 | /** |
69 | * Compares this constant expression against another constant expression of the same type. It is |
70 | * an error to call this on non-constant expressions, or if the types of the expressions do not |
71 | * match. |
72 | */ |
73 | virtual bool compareConstant(const Context& context, const Expression& other) const { |
74 | ABORT("cannot call compareConstant on this type" ); |
75 | } |
76 | |
77 | /** |
78 | * For an expression which evaluates to a constant int, returns the value. Otherwise calls |
79 | * ABORT. |
80 | */ |
81 | virtual int64_t getConstantInt() const { |
82 | ABORT("not a constant int" ); |
83 | } |
84 | |
85 | /** |
86 | * For an expression which evaluates to a constant float, returns the value. Otherwise calls |
87 | * ABORT. |
88 | */ |
89 | virtual double getConstantFloat() const { |
90 | ABORT("not a constant float" ); |
91 | } |
92 | |
93 | virtual bool hasProperty(Property property) const = 0; |
94 | |
95 | bool hasSideEffects() const { |
96 | return this->hasProperty(Property::kSideEffects); |
97 | } |
98 | |
99 | bool containsRTAdjust() const { |
100 | return this->hasProperty(Property::kContainsRTAdjust); |
101 | } |
102 | |
103 | /** |
104 | * Given a map of known constant variable values, substitute them in for references to those |
105 | * variables occurring in this expression and its subexpressions. Similar simplifications, such |
106 | * as folding a constant binary expression down to a single value, may also be performed. |
107 | * Returns a new expression which replaces this expression, or null if no replacements were |
108 | * made. If a new expression is returned, this expression is no longer valid. |
109 | */ |
110 | virtual std::unique_ptr<Expression> constantPropagate(const IRGenerator& irGenerator, |
111 | const DefinitionMap& definitions) { |
112 | return nullptr; |
113 | } |
114 | |
115 | virtual int coercionCost(const Type& target) const { |
116 | return fType.coercionCost(target); |
117 | } |
118 | |
119 | /** |
120 | * For a literal vector expression, return the floating point value of the n'th vector |
121 | * component. It is an error to call this method on an expression which is not a literal vector. |
122 | */ |
123 | virtual SKSL_FLOAT getFVecComponent(int n) const { |
124 | SkASSERT(false); |
125 | return 0; |
126 | } |
127 | |
128 | /** |
129 | * For a literal vector expression, return the integer value of the n'th vector component. It is |
130 | * an error to call this method on an expression which is not a literal vector. |
131 | */ |
132 | virtual SKSL_INT getIVecComponent(int n) const { |
133 | SkASSERT(false); |
134 | return 0; |
135 | } |
136 | |
137 | /** |
138 | * For a literal matrix expression, return the floating point value of the component at |
139 | * [col][row]. It is an error to call this method on an expression which is not a literal |
140 | * matrix. |
141 | */ |
142 | virtual SKSL_FLOAT getMatComponent(int col, int row) const { |
143 | SkASSERT(false); |
144 | return 0; |
145 | } |
146 | |
147 | virtual std::unique_ptr<Expression> clone() const = 0; |
148 | |
149 | const Kind fKind; |
150 | const Type& fType; |
151 | |
152 | typedef IRNode INHERITED; |
153 | }; |
154 | |
155 | } // namespace |
156 | |
157 | #endif |
158 | |