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_VARIABLEREFERENCE |
9 | #define SKSL_VARIABLEREFERENCE |
10 | |
11 | #include "src/sksl/ir/SkSLExpression.h" |
12 | |
13 | namespace SkSL { |
14 | |
15 | class IRGenerator; |
16 | |
17 | /** |
18 | * A reference to a variable, through which it can be read or written. In the statement: |
19 | * |
20 | * x = x + 1; |
21 | * |
22 | * there is only one Variable 'x', but two VariableReferences to it. |
23 | */ |
24 | struct VariableReference : public Expression { |
25 | enum RefKind { |
26 | kRead_RefKind, |
27 | kWrite_RefKind, |
28 | kReadWrite_RefKind, |
29 | // taking the address of a variable - we consider this a read & write but don't complain if |
30 | // the variable was not previously assigned |
31 | kPointer_RefKind |
32 | }; |
33 | |
34 | VariableReference(int offset, const Variable& variable, RefKind refKind = kRead_RefKind); |
35 | |
36 | ~VariableReference() override; |
37 | |
38 | VariableReference(const VariableReference&) = delete; |
39 | VariableReference& operator=(const VariableReference&) = delete; |
40 | |
41 | RefKind refKind() const { |
42 | return fRefKind; |
43 | } |
44 | |
45 | void setRefKind(RefKind refKind); |
46 | |
47 | bool hasProperty(Property property) const override { |
48 | switch (property) { |
49 | case Property::kSideEffects: return false; |
50 | case Property::kContainsRTAdjust: return fVariable.fName == "sk_RTAdjust" ; |
51 | default: |
52 | SkASSERT(false); |
53 | return false; |
54 | } |
55 | } |
56 | |
57 | bool isConstant() const override { |
58 | return 0 != (fVariable.fModifiers.fFlags & Modifiers::kConst_Flag); |
59 | } |
60 | |
61 | std::unique_ptr<Expression> clone() const override { |
62 | return std::unique_ptr<Expression>(new VariableReference(fOffset, fVariable, fRefKind)); |
63 | } |
64 | |
65 | #ifdef SK_DEBUG |
66 | String description() const override { |
67 | return fVariable.fName; |
68 | } |
69 | #endif |
70 | |
71 | static std::unique_ptr<Expression> copy_constant(const IRGenerator& irGenerator, |
72 | const Expression* expr); |
73 | |
74 | std::unique_ptr<Expression> constantPropagate(const IRGenerator& irGenerator, |
75 | const DefinitionMap& definitions) override; |
76 | |
77 | const Variable& fVariable; |
78 | RefKind fRefKind; |
79 | |
80 | private: |
81 | typedef Expression INHERITED; |
82 | }; |
83 | |
84 | } // namespace |
85 | |
86 | #endif |
87 | |