降低罗斯林的操作

Question

在 Roslyn 中引入操作时，其中一个目标是提供低级操作（我认为是在设计评审会议视频中），据我所知，它应该为高级操作上的隐式编译器操作提供显式操作。我在 Roslyn 看到了降低目录，但类是内部的。现在可以降低操作还是没有可用的公共 API？

在下面的示例中，操作已经删除了一些隐式部分 - 为表达式主体添加返回语句并为重载运算符公开符号。但前后增量仅在种类上有所不同。

using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Semantics;
using System.Linq;

namespace so39468373
{
    internal static class Program
    {
        private static void Main()
        {
            var tree = CSharpSyntaxTree.ParseText(@"
public class c
{
    public static c operator ++(c o) { return o; }
    static c pre(c o) => ++o;
    static c post(c o) => o++;
    public static void Main() {}
}");
            var mscorlib = MetadataReference.CreateFromFile(typeof(object).Assembly.Location);
            var compilation = CSharpCompilation.Create(null, new[] { tree }, new[] { mscorlib });
            var model = compilation.GetSemanticModel(tree);
            foreach (var node in tree.GetRoot().DescendantNodes().OfType<ArrowExpressionClauseSyntax>())
            {
                var operation = model.GetOperation(node);
                var block = (IBlockStatement)operation;
                var statement = (IReturnStatement)block.Statements.First();
                var increment = (IIncrementExpression)statement.ReturnedValue;
                // How to get lowered operations for increment here?
            }
        }
    }
}

github上的代码-https://github.com/isanych/so-39468373

Answer 1

这个答案的不同角度——编译器的这个方面呢？

InternalVisibleTo Attribute

链接：https://msdn.microsoft.com/en-us/library/system.runtime.compilerservices.internalsvisibletoattribute(v=vs.110).aspx

可能会提出一个与“不同角度”相关的有趣话题来进行调试？

更多信息（来自文章）：

版本信息

通用 Windows 平台 从 8 开始可用 .NET 框架
自 2.0 起可用 可移植类库
支持：便携式 .NET 平台 银光
自 2.0 起可用 Windows Phone Silverlight
自 7.0 起可用 Windows 手机
从 8.1 开始提供

Answer 2

检查这个例子将帮助你解决他的问题

using System.Collections.Immutable;
using System.Diagnostics;
using Microsoft.CodeAnalysis.CSharp.Symbols;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Text;

namespace Microsoft.CodeAnalysis.CSharp
{
    /// <summary>
    /// The dynamic operation factories below return this struct so that the caller
    /// have the option of separating the call-site initialization from its invocation.
    /// 
    /// Most callers just call <see cref="ToExpression"/> to get the combo but some (object and array initializers) 
    /// hoist all call-site initialization code and emit multiple invocations of the same site.
    /// </summary>
    internal struct LoweredDynamicOperation
    {
        private readonly SyntheticBoundNodeFactory _factory;
        private readonly TypeSymbol _resultType;
        private readonly ImmutableArray<LocalSymbol> _temps;
        public readonly BoundExpression SiteInitialization;
        public readonly BoundExpression SiteInvocation;

        public LoweredDynamicOperation(SyntheticBoundNodeFactory factory, BoundExpression siteInitialization, BoundExpression siteInvocation, TypeSymbol resultType, ImmutableArray<LocalSymbol> temps)
        {
            _factory = factory;
            _resultType = resultType;
            _temps = temps;
            this.SiteInitialization = siteInitialization;
            this.SiteInvocation = siteInvocation;
        }

        public static LoweredDynamicOperation Bad(
            BoundExpression loweredReceiver,
            ImmutableArray<BoundExpression> loweredArguments,
            BoundExpression loweredRight,
            TypeSymbol resultType)
        {
            var children = ArrayBuilder<BoundNode>.GetInstance();
            children.AddOptional(loweredReceiver);
            children.AddRange(loweredArguments);
            children.AddOptional(loweredRight);

            return LoweredDynamicOperation.Bad(resultType, children.ToImmutableAndFree());
        }

        public static LoweredDynamicOperation Bad(TypeSymbol resultType, ImmutableArray<BoundNode> children)
        {
            Debug.Assert(children.Length > 0);
            var bad = new BoundBadExpression(children[0].Syntax, LookupResultKind.Empty, ImmutableArray<Symbol>.Empty, children, resultType);
            return new LoweredDynamicOperation(null, null, bad, resultType, default(ImmutableArray<LocalSymbol>));
        }

        public BoundExpression ToExpression()
        {
            if (_factory == null)
            {
                Debug.Assert(SiteInitialization == null && SiteInvocation is BoundBadExpression && _temps.IsDefaultOrEmpty);
                return SiteInvocation;
            }

            // TODO (tomat): we might be able to use SiteInvocation.Type instead of resultType once we stop using GetLoweredType
            if (_temps.IsDefaultOrEmpty)
            {
                return _factory.Sequence(new[] { SiteInitialization }, SiteInvocation, _resultType);
            }
            else
            {
                return new BoundSequence(_factory.Syntax, _temps, ImmutableArray.Create(SiteInitialization), SiteInvocation, _resultType) { WasCompilerGenerated = true };
            }
        }
    }
}