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[wasm][debugger] Improvement of memory consumption while Evaluating Expressions #61470

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merged 15 commits into from
Nov 16, 2021
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@
</PropertyGroup>

<ItemGroup>
<PackageReference Include="Microsoft.CodeAnalysis.CSharp.Scripting" Version="3.7.0" />
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For future PR, we should consider using the common version (more than one!) property for this, being used in other places in the repo.

<PackageReference Include="Microsoft.Extensions.Logging" Version="3.1.7" />
<PackageReference Include="Newtonsoft.Json" Version="12.0.3" />
<PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.7.0" />
Expand Down
199 changes: 73 additions & 126 deletions src/mono/wasm/debugger/BrowserDebugProxy/EvaluateExpression.cs
Original file line number Diff line number Diff line change
Expand Up @@ -12,17 +12,21 @@
using System.Threading.Tasks;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Scripting;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Emit;
using Microsoft.CodeAnalysis.Scripting;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.Text.RegularExpressions;

namespace Microsoft.WebAssembly.Diagnostics
{
internal static class EvaluateExpression
{
private class FindVariableNMethodCall : CSharpSyntaxWalker
{
private static Regex regexForReplaceVarName = new Regex(@"[^A-Za-z0-9_]", RegexOptions.Singleline);
public List<IdentifierNameSyntax> identifiers = new List<IdentifierNameSyntax>();
public List<InvocationExpressionSyntax> methodCall = new List<InvocationExpressionSyntax>();
public List<MemberAccessExpressionSyntax> memberAccesses = new List<MemberAccessExpressionSyntax>();
Expand All @@ -32,6 +36,7 @@ private class FindVariableNMethodCall : CSharpSyntaxWalker
private int visitCount;
public bool hasMethodCalls;
public bool hasElementAccesses;
internal List<string> variableDefinitions = new List<string>();

public void VisitInternal(SyntaxNode node)
{
Expand Down Expand Up @@ -97,7 +102,7 @@ public SyntaxTree ReplaceVars(SyntaxTree syntaxTree, IEnumerable<JObject> ma_val
{
// Generate a random suffix
string suffix = Guid.NewGuid().ToString().Substring(0, 5);
string prefix = ma_str.Trim().Replace(".", "_");
string prefix = regexForReplaceVarName.Replace(ma_str, "_");
id_name = $"{prefix}_{suffix}";

memberAccessToParamName[ma_str] = id_name;
Expand All @@ -114,7 +119,7 @@ public SyntaxTree ReplaceVars(SyntaxTree syntaxTree, IEnumerable<JObject> ma_val
{
// Generate a random suffix
string suffix = Guid.NewGuid().ToString().Substring(0, 5);
string prefix = iesStr.Trim().Replace(".", "_").Replace("(", "_").Replace(")", "_");
string prefix = regexForReplaceVarName.Replace(iesStr, "_");
id_name = $"{prefix}_{suffix}";
methodCallToParamName[iesStr] = id_name;
}
Expand All @@ -138,7 +143,7 @@ public SyntaxTree ReplaceVars(SyntaxTree syntaxTree, IEnumerable<JObject> ma_val
return SyntaxFactory.IdentifierName(id_name);
});

var paramsSet = new HashSet<string>();
var localsSet = new HashSet<string>();

// 2. For every unique member ref, add a corresponding method param
if (ma_values != null)
Expand All @@ -151,15 +156,15 @@ public SyntaxTree ReplaceVars(SyntaxTree syntaxTree, IEnumerable<JObject> ma_val
throw new Exception($"BUG: Expected to find an id name for the member access string: {node_str}");
}
memberAccessValues[id_name] = value;
root = UpdateWithNewMethodParam(root, id_name, value);
AddLocalVariableWithValue(id_name, value);
}
}

if (id_values != null)
{
foreach ((IdentifierNameSyntax idns, JObject value) in identifiers.Zip(id_values))
{
root = UpdateWithNewMethodParam(root, idns.Identifier.Text, value);
AddLocalVariableWithValue(idns.Identifier.Text, value);
}
}

Expand All @@ -172,7 +177,7 @@ public SyntaxTree ReplaceVars(SyntaxTree syntaxTree, IEnumerable<JObject> ma_val
{
throw new Exception($"BUG: Expected to find an id name for the member access string: {node_str}");
}
root = UpdateWithNewMethodParam(root, id_name, value);
AddLocalVariableWithValue(id_name, value);
}
}

Expand All @@ -185,96 +190,73 @@ public SyntaxTree ReplaceVars(SyntaxTree syntaxTree, IEnumerable<JObject> ma_val
{
throw new Exception($"BUG: Expected to find an id name for the element access string: {node_str}");
}
root = UpdateWithNewMethodParam(root, id_name, value);
AddLocalVariableWithValue(id_name, value);
}
}

return syntaxTree.WithRootAndOptions(root, syntaxTree.Options);

CompilationUnitSyntax UpdateWithNewMethodParam(CompilationUnitSyntax root, string id_name, JObject value)
void AddLocalVariableWithValue(string idName, JObject value)
{
var classDeclaration = root.Members.ElementAt(0) as ClassDeclarationSyntax;
var method = classDeclaration.Members.ElementAt(0) as MethodDeclarationSyntax;

if (paramsSet.Contains(id_name))
{
// repeated member access expression
// eg. this.a + this.a
return root;
}

argValues.Add(ConvertJSToCSharpType(value));

MethodDeclarationSyntax updatedMethod = method.AddParameterListParameters(
SyntaxFactory.Parameter(
SyntaxFactory.Identifier(id_name))
.WithType(SyntaxFactory.ParseTypeName(GetTypeFullName(value))));

paramsSet.Add(id_name);
root = root.ReplaceNode(method, updatedMethod);

return root;
if (localsSet.Contains(idName))
return;
localsSet.Add(idName);
variableDefinitions.Add(ConvertJSToCSharpLocalVariableAssignment(idName, value));
}
}

private object ConvertJSToCSharpType(JToken variable)
private string ConvertJSToCSharpLocalVariableAssignment(string idName, JToken variable)
{
string typeRet;
object valueRet;
JToken value = variable["value"];
string type = variable["type"].Value<string>();
string subType = variable["subtype"]?.Value<string>();

string objectId = variable["objectId"]?.Value<string>();
switch (type)
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{
case "string":
return value?.Value<string>();
{
var str = value?.Value<string>();
str = str.Replace("\"", "\\\"");
valueRet = $"\"{str}\"";
typeRet = valueRet.GetType().FullName;
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break;
}
case "number":
return value?.Value<double>();
valueRet = value?.Value<double>();
typeRet = valueRet.GetType().FullName;
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break;
case "boolean":
return value?.Value<bool>();
valueRet = value?.Value<string>().ToLower();
typeRet = "System.Boolean";
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break;
case "object":
return variable;
valueRet = "Newtonsoft.Json.Linq.JObject.FromObject(new {"
+ $"type = \"{type}\""
+ $", description = \"{variable["description"].Value<string>()}\""
+ $", className = \"{variable["className"].Value<string>()}\""
+ (subType != null ? $", subtype = \"{subType}\"" : "")
+ (objectId != null ? $", objectId = \"{objectId}\"" : "")
+ "})";
typeRet = "object";
break;
case "void":
return null;
}
throw new Exception($"Evaluate of this datatype {type} not implemented yet");//, "Unsupported");
}

private string GetTypeFullName(JToken variable)
{
string type = variable["type"].ToString();
string subType = variable["subtype"]?.Value<string>();
object value = ConvertJSToCSharpType(variable);

switch (type)
{
case "object":
{
if (subType == "null")
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return variable["className"].Value<string>();
else
return "object";
}
case "void":
return "object";
valueRet = "Newtonsoft.Json.Linq.JObject.FromObject(new {"
+ $"type = \"object\","
+ $"description = \"object\","
+ $"className = \"object\","
+ $"subtype = \"null\""
+ "})";
typeRet = "object";
break;
Comment on lines +242 to +259
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I'm not sure I understand these two.

  1. why do we need to use JObjects in the script?
  2. case "object": - would it be better to use Newtonsoft.Json.Linq.JObject.Parse(..) and pass the escaped string for variable?
  3. case "void": - why is this needed? And what does the variable look like here? And do we have a test for this?

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  1. Because that is how we return simple variable values, so when it's something that we really need to execute we also keep the same way of returning the value.
  2. I think it's faster to not parse the string? once this is already parsed we don't need to parse it again?
  3. Yes, the tests evaluating method that return void.

default:
return value.GetType().FullName;
throw new Exception($"Evaluate of this datatype {type} not implemented yet");//, "Unsupported");
}
throw new ReturnAsErrorException($"GetTypefullName: Evaluate of this datatype {type} not implemented yet", "Unsupported");
return $"{typeRet} {idName} = {valueRet};";
}
}

private static SyntaxNode GetExpressionFromSyntaxTree(SyntaxTree syntaxTree)
{
CompilationUnitSyntax root = syntaxTree.GetCompilationUnitRoot();
ClassDeclarationSyntax classDeclaration = root.Members.ElementAt(0) as ClassDeclarationSyntax;
MethodDeclarationSyntax methodDeclaration = classDeclaration.Members.ElementAt(0) as MethodDeclarationSyntax;
BlockSyntax blockValue = methodDeclaration.Body;
ReturnStatementSyntax returnValue = blockValue.Statements.ElementAt(0) as ReturnStatementSyntax;
ParenthesizedExpressionSyntax expressionParenthesized = returnValue.Expression as ParenthesizedExpressionSyntax;

return expressionParenthesized?.Expression;
}

private static async Task<IList<JObject>> ResolveMemberAccessExpressions(IEnumerable<MemberAccessExpressionSyntax> member_accesses,
MemberReferenceResolver resolver, CancellationToken token)
{
Expand Down Expand Up @@ -335,32 +317,20 @@ private static async Task<IList<JObject>> ResolveElementAccess(IEnumerable<Eleme
return values;
}

[UnconditionalSuppressMessage("SingleFile", "IL3000:Avoid accessing Assembly file path when publishing as a single file",
Justification = "Suppressing the warning until gets fixed, see https://github.com/dotnet/runtime/issues/51202")]
internal static async Task<JObject> CompileAndRunTheExpression(string expression, MemberReferenceResolver resolver, CancellationToken token)
{
expression = expression.Trim();
if (!expression.StartsWith('('))
{
expression = "(" + expression + ")";
}
SyntaxTree syntaxTree = CSharpSyntaxTree.ParseText(@"
using System;
public class CompileAndRunTheExpression
{
public static object Evaluate()
{
return " + expression + @";
}
}", cancellationToken: token);
SyntaxTree syntaxTree = CSharpSyntaxTree.ParseText(expression + @";", cancellationToken: token);

SyntaxNode expressionTree = GetExpressionFromSyntaxTree(syntaxTree);
SyntaxNode expressionTree = syntaxTree.GetCompilationUnitRoot(token);
if (expressionTree == null)
throw new Exception($"BUG: Unable to evaluate {expression}, could not get expression from the syntax tree");

FindVariableNMethodCall findVarNMethodCall = new FindVariableNMethodCall();
findVarNMethodCall.VisitInternal(expressionTree);

// this fails with `"a)"`
// because the code becomes: return (a));
// and the returned expression from GetExpressionFromSyntaxTree is `a`!
Expand Down Expand Up @@ -388,7 +358,7 @@ public static object Evaluate()

if (findVarNMethodCall.hasMethodCalls)
{
expressionTree = GetExpressionFromSyntaxTree(syntaxTree);
expressionTree = syntaxTree.GetCompilationUnitRoot(token);

findVarNMethodCall.VisitInternal(expressionTree);

Expand All @@ -400,7 +370,7 @@ public static object Evaluate()
// eg. "elements[0]"
if (findVarNMethodCall.hasElementAccesses)
{
expressionTree = GetExpressionFromSyntaxTree(syntaxTree);
expressionTree = syntaxTree.GetCompilationUnitRoot(token);

findVarNMethodCall.VisitInternal(expressionTree);

Expand All @@ -409,48 +379,25 @@ public static object Evaluate()
syntaxTree = findVarNMethodCall.ReplaceVars(syntaxTree, null, null, null, elementAccessValues);
}

expressionTree = GetExpressionFromSyntaxTree(syntaxTree);
expressionTree = syntaxTree.GetCompilationUnitRoot(token);
if (expressionTree == null)
throw new Exception($"BUG: Unable to evaluate {expression}, could not get expression from the syntax tree");

MetadataReference[] references = new MetadataReference[]
{
MetadataReference.CreateFromFile(typeof(object).Assembly.Location),
MetadataReference.CreateFromFile(typeof(Enumerable).Assembly.Location)
};

CSharpCompilation compilation = CSharpCompilation.Create(
"compileAndRunTheExpression",
syntaxTrees: new[] { syntaxTree },
references: references,
options: new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary));

SemanticModel semanticModel = compilation.GetSemanticModel(syntaxTree);
CodeAnalysis.TypeInfo TypeInfo = semanticModel.GetTypeInfo(expressionTree, cancellationToken: token);

using (var ms = new MemoryStream())
try {
var result = await CSharpScript.EvaluateAsync(
string.Join("\n", findVarNMethodCall.variableDefinitions) + "\nreturn " + syntaxTree.ToString(),
ScriptOptions.Default.WithReferences(
typeof(object).Assembly,
typeof(Enumerable).Assembly,
typeof(JObject).Assembly
),
cancellationToken: token);
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If we specifically catch CompilationErrorException here, can we surface the error to VS? or maybe just return the exception message like on line 400.

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Do I understand it correctly that if the expression itself throws an exception, then we return the message on line 400? Can we detect this specific case of the expression itself throwing, and return a different message?

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If we specifically catch CompilationErrorException here, can we surface the error to VS? or maybe just return the exception message like on line 400.

IIUC, this would be thrown if our constructed script fails to compile, so maybe the message doesn't need to be shown to the user.

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Do I understand it correctly that if the expression itself throws an exception, then we return the message on line 400? Can we detect this specific case of the expression itself throwing, and return a different message?

Looking at the code there is some handling for exceptions, though specifically System.Exception, and that then returns the message.

Though looking at it, this.PropertyThrowException correctly returns the exception message, but this.ParmToTestObjException.MyMethod() doesn't.

This doesn't need to be handled for this PR though.

return JObject.FromObject(ConvertCSharpToJSType(result, result.GetType()));
}
catch (Exception)
{
EmitResult result = compilation.Emit(ms, cancellationToken: token);
if (!result.Success)
{
var sb = new StringBuilder();
foreach (Diagnostic d in result.Diagnostics)
sb.Append(d.ToString());

throw new ReturnAsErrorException(sb.ToString(), "CompilationError");
}

ms.Seek(0, SeekOrigin.Begin);
Assembly assembly = Assembly.Load(ms.ToArray());
Type type = assembly.GetType("CompileAndRunTheExpression");

object ret = type.InvokeMember("Evaluate",
BindingFlags.InvokeMethod | BindingFlags.Static | BindingFlags.Public,
null,
null,
findVarNMethodCall.argValues.ToArray());

return JObject.FromObject(ConvertCSharpToJSType(ret, TypeInfo.Type));
Console.WriteLine(string.Join("\n", findVarNMethodCall.variableDefinitions) + "\nreturn " + syntaxTree.ToString());
throw new ReturnAsErrorException($"Cannot evaluate '{expression}'.", "CompilationError");
}
}

Expand All @@ -462,7 +409,7 @@ public static object Evaluate()
typeof(float), typeof(double)
};

private static object ConvertCSharpToJSType(object v, ITypeSymbol type)
private static object ConvertCSharpToJSType(object v, Type type)
{
if (v == null)
return new { type = "object", subtype = "null", className = type.ToString(), description = type.ToString() };
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -461,7 +461,7 @@ public async Task NegativeTestsInStaticMethod() => await CheckInspectLocalsAtBre

await EvaluateOnCallFrameFail(id,
("me.foo", "ReferenceError"),
("this", "ReferenceError"),
("this", "CompilationError"),
("this.NullIfAIsNotZero.foo", "ReferenceError"));
});

Expand Down Expand Up @@ -542,6 +542,11 @@ await EvaluateOnCallFrameAndCheck(id,
("this.CallMethodWithParmBool(true)", TString("TRUE")),
("this.CallMethodWithParmBool(false)", TString("FALSE")),
("this.CallMethodWithParmString(\"concat\")", TString("str_const_concat")),
("this.CallMethodWithParmString(\"\\\"\\\"\")", TString("str_const_\"\"")),
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("this.CallMethodWithParmString(\"🛶\")", TString("str_const_🛶")),
("this.CallMethodWithParmString(\"\\uD83D\\uDEF6\")", TString("str_const_🛶")),
("this.CallMethodWithParmString(\"🚀\")", TString("str_const_🚀")),
("this.CallMethodWithParmString_λ(\"🚀\")", TString("λ_🚀")),
("this.CallMethodWithParm(10) + this.a", TNumber(12)),
("this.CallMethodWithObj(null)", TNumber(-1)),
("this.CallMethodWithChar('a')", TString("str_const_a")));
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -378,6 +378,11 @@ public string CallMethodWithParmString(string parm)
return str + parm;
}

public string CallMethodWithParmString_λ(string parm)
{
return "λ_" + parm;
}

public string CallMethodWithParmBool(bool parm)
{
if (parm)
Expand Down