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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
|
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System;
using System.Collections.Immutable;
using System.Diagnostics;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.FlowAnalysis;
using Microsoft.CodeAnalysis.Operations;
namespace ILLink.RoslynAnalyzer
{
// Copied from https://github.com/dotnet/roslyn/blob/9c6d864baca08d7572871701ab583cec18279426/src/Compilers/Core/Portable/Operations/OperationExtensions.cs
internal static partial class OperationExtensions
{
/// <summary>
/// Returns the <see cref="ValueUsageInfo"/> for the given operation.
/// This extension can be removed once https://github.com/dotnet/roslyn/issues/25057 is implemented.
/// </summary>
public static ValueUsageInfo GetValueUsageInfo (this IOperation operation, ISymbol containingSymbol)
{
/*
| code | Read | Write | ReadableRef | WritableRef | NonReadWriteRef |
| x.Prop = 1 | | ✔️ | | | |
| x.Prop += 1 | ✔️ | ✔️ | | | |
| x.Prop++ | ✔️ | ✔️ | | | |
| Foo(x.Prop) | ✔️ | | | | |
| Foo(x.Prop), | | | ✔️ | | |
where void Foo(in T v)
| Foo(out x.Prop) | | | | ✔️ | |
| Foo(ref x.Prop) | | | ✔️ | ✔️ | |
| nameof(x) | | | | | ✔️ | ️
| sizeof(x) | | | | | ✔️ | ️
| typeof(x) | | | | | ✔️ | ️
| out var x | | ✔️ | | | | ️
| case X x: | | ✔️ | | | | ️
| obj is X x | | ✔️ | | | |
| ref var x = | | | ✔️ | ✔️ | |
| ref readonly var x = | | | ✔️ | | |
*/
if (operation is ILocalReferenceOperation localReference &&
localReference.IsDeclaration &&
!localReference.IsImplicit) // Workaround for https://github.com/dotnet/roslyn/issues/30753
{
// Declaration expression is a definition (write) for the declared local.
return ValueUsageInfo.Write;
} else if (operation is IDeclarationPatternOperation) {
while (operation.Parent is IBinaryPatternOperation ||
operation.Parent is INegatedPatternOperation ||
operation.Parent is IRelationalPatternOperation) {
operation = operation.Parent;
}
switch (operation.Parent) {
case IPatternCaseClauseOperation _:
// A declaration pattern within a pattern case clause is a
// write for the declared local.
// For example, 'x' is defined and assigned the value from 'obj' below:
// switch (obj)
// {
// case X x:
//
return ValueUsageInfo.Write;
case IRecursivePatternOperation _:
// A declaration pattern within a recursive pattern is a
// write for the declared local.
// For example, 'x' is defined and assigned the value from 'obj' below:
// (obj) switch
// {
// (X x) => ...
// };
//
return ValueUsageInfo.Write;
case ISwitchExpressionArmOperation _:
// A declaration pattern within a switch expression arm is a
// write for the declared local.
// For example, 'x' is defined and assigned the value from 'obj' below:
// obj switch
// {
// X x => ...
//
return ValueUsageInfo.Write;
case IIsPatternOperation _:
// A declaration pattern within an is pattern is a
// write for the declared local.
// For example, 'x' is defined and assigned the value from 'obj' below:
// if (obj is X x)
//
return ValueUsageInfo.Write;
case IPropertySubpatternOperation _:
// A declaration pattern within a property sub-pattern is a
// write for the declared local.
// For example, 'x' is defined and assigned the value from 'obj.Property' below:
// if (obj is { Property : int x })
//
return ValueUsageInfo.Write;
default:
Debug.Fail ("Unhandled declaration pattern context");
// Conservatively assume read/write.
return ValueUsageInfo.ReadWrite;
}
}
if (operation.Parent is IAssignmentOperation assignmentOperation &&
assignmentOperation.Target == operation) {
return operation.Parent.IsAnyCompoundAssignment ()
? ValueUsageInfo.ReadWrite
: ValueUsageInfo.Write;
} else if (operation.Parent is IIncrementOrDecrementOperation) {
return ValueUsageInfo.ReadWrite;
} else if (operation.Parent is IParenthesizedOperation parenthesizedOperation) {
// Note: IParenthesizedOperation is specific to VB, where the parens cause a copy, so this cannot be classified as a write.
Debug.Assert (parenthesizedOperation.Language == LanguageNames.VisualBasic);
return parenthesizedOperation.GetValueUsageInfo (containingSymbol) &
~(ValueUsageInfo.Write | ValueUsageInfo.Reference);
} else if (operation.Parent is INameOfOperation ||
operation.Parent is ITypeOfOperation ||
operation.Parent is ISizeOfOperation) {
return ValueUsageInfo.Name;
} else if (operation.Parent is IArgumentOperation argumentOperation) {
switch (argumentOperation.Parameter.RefKind) {
case RefKind.RefReadOnly:
return ValueUsageInfo.ReadableReference;
case RefKind.Out:
return ValueUsageInfo.WritableReference;
case RefKind.Ref:
return ValueUsageInfo.ReadableWritableReference;
default:
return ValueUsageInfo.Read;
}
} else if (operation.Parent is IReturnOperation returnOperation) {
return returnOperation.GetRefKind (containingSymbol) switch
{
RefKind.RefReadOnly => ValueUsageInfo.ReadableReference,
RefKind.Ref => ValueUsageInfo.ReadableWritableReference,
_ => ValueUsageInfo.Read,
};
} else if (operation.Parent is IConditionalOperation conditionalOperation) {
if (operation == conditionalOperation.WhenTrue
|| operation == conditionalOperation.WhenFalse) {
return GetValueUsageInfo (conditionalOperation, containingSymbol);
} else {
return ValueUsageInfo.Read;
}
} else if (operation.Parent is IReDimClauseOperation reDimClauseOperation &&
reDimClauseOperation.Operand == operation) {
return (reDimClauseOperation.Parent as IReDimOperation)?.Preserve == true
? ValueUsageInfo.ReadWrite
: ValueUsageInfo.Write;
} else if (operation.Parent is IDeclarationExpressionOperation declarationExpression) {
return declarationExpression.GetValueUsageInfo (containingSymbol);
} else if (operation.IsInLeftOfDeconstructionAssignment (out _)) {
return ValueUsageInfo.Write;
} else if (operation.Parent is IVariableInitializerOperation variableInitializerOperation) {
if (variableInitializerOperation.Parent is IVariableDeclaratorOperation variableDeclaratorOperation) {
switch (variableDeclaratorOperation.Symbol.RefKind) {
case RefKind.Ref:
return ValueUsageInfo.ReadableWritableReference;
case RefKind.RefReadOnly:
return ValueUsageInfo.ReadableReference;
}
}
}
return ValueUsageInfo.Read;
}
public static RefKind GetRefKind (this IReturnOperation operation, ISymbol containingSymbol)
{
var containingMethod = TryGetContainingAnonymousFunctionOrLocalFunction (operation) ?? (containingSymbol as IMethodSymbol);
return containingMethod?.RefKind ?? RefKind.None;
}
public static IMethodSymbol? TryGetContainingAnonymousFunctionOrLocalFunction (this IOperation? operation)
{
operation = operation?.Parent;
while (operation != null) {
switch (operation.Kind) {
case OperationKind.AnonymousFunction:
return ((IAnonymousFunctionOperation) operation).Symbol;
case OperationKind.LocalFunction:
return ((ILocalFunctionOperation) operation).Symbol;
}
operation = operation.Parent;
}
return null;
}
public static bool IsInLeftOfDeconstructionAssignment (this IOperation operation, out IDeconstructionAssignmentOperation? deconstructionAssignment)
{
deconstructionAssignment = null;
var previousOperation = operation;
operation = operation.Parent;
while (operation != null) {
switch (operation.Kind) {
case OperationKind.DeconstructionAssignment:
deconstructionAssignment = (IDeconstructionAssignmentOperation) operation;
return deconstructionAssignment.Target == previousOperation;
case OperationKind.Tuple:
case OperationKind.Conversion:
case OperationKind.Parenthesized:
previousOperation = operation;
operation = operation.Parent;
continue;
default:
return false;
}
}
return false;
}
/// <summary>
/// Retursn true if the given operation is a regular compound assignment,
/// i.e. <see cref="ICompoundAssignmentOperation"/> such as <code>a += b</code>,
/// or a special null coalescing compoud assignment, i.e. <see cref="ICoalesceAssignmentOperation"/>
/// such as <code>a ??= b</code>.
/// </summary>
public static bool IsAnyCompoundAssignment (this IOperation operation)
{
switch (operation) {
case ICompoundAssignmentOperation _:
case ICoalesceAssignmentOperation _:
return true;
default:
return false;
}
}
}
}
|
