Preparation to introduce parallelism into CrossGen2 (#27068)

* Preparation to introduce parallelism into CrossGen2

- Change dictionaries in ReadyToRunCodegenNodeFactory and ReadyToRunSymbolNodeFactory to NodeCaches (i.e. ConcurrentDictionary, at the moment)
- Add structs to act as keys for the above NodeCaches (MethodFixupKey, DynamicHelperKey, ReadyToRunHelperKey)
- Synchronize logger
- Update some Dictionaries to ConcurrentDictionary
- Add .Equals and GetHashCode to SignatureContext.

src/tools/crossgen2/Common/Compiler/Logger.cs

@@ -18,7 +18,7 @@ public class Logger
 
         public Logger(TextWriter writer, bool isVerbose)
         {
-            Writer = writer;
+            Writer = TextWriter.Synchronized(writer);
             IsVerbose = isVerbose;
         }
     }

src/tools/crossgen2/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/MethodWithGCInfo.cs

@@ -5,8 +5,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
-
-using ILCompiler.DependencyAnalysis;
+using System.Threading;
 
 using Internal.JitInterface;
 using Internal.Text;

src/tools/crossgen2/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/ModuleTokenResolver.cs

@@ -3,7 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Collections.Generic;
+using System.Collections.Concurrent;
 using System.Collections.Immutable;
 using System.Reflection.Metadata;
 using System.Reflection.Metadata.Ecma335;
@@ -25,9 +25,9 @@ public class ModuleTokenResolver
         /// Reverse lookup table mapping external types to reference tokens in the input modules. The table
         /// gets lazily initialized as various tokens are resolved in CorInfoImpl.
         /// </summary>
-        private readonly Dictionary<EcmaType, ModuleToken> _typeToRefTokens = new Dictionary<EcmaType, ModuleToken>();
+        private readonly ConcurrentDictionary<EcmaType, ModuleToken> _typeToRefTokens = new ConcurrentDictionary<EcmaType, ModuleToken>();
 
-        private readonly Dictionary<FieldDesc, ModuleToken> _fieldToRefTokens = new Dictionary<FieldDesc, ModuleToken>();
+        private readonly ConcurrentDictionary<FieldDesc, ModuleToken> _fieldToRefTokens = new ConcurrentDictionary<FieldDesc, ModuleToken>();
 
         private readonly CompilationModuleGroup _compilationModuleGroup;
 
@@ -163,6 +163,7 @@ public void AddModuleTokenForField(FieldDesc field, ModuleToken token)
             }
 
             _fieldToRefTokens[canonField] = token;
+
             switch (token.TokenType)
             {
                 case CorTokenType.mdtMemberRef:

src/tools/crossgen2/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/SignatureContext.cs

@@ -83,5 +83,22 @@ public ModuleToken GetModuleTokenForField(FieldDesc field, bool throwIfNotFound
         {
             return Resolver.GetModuleTokenForField(field, throwIfNotFound);
         }
+
+        public bool Equals(SignatureContext other)
+        {
+            return GlobalContext == other.GlobalContext
+                && LocalContext == other.LocalContext;
+        }
+
+        public override bool Equals(object obj)
+        {
+            return obj is SignatureContext other && Equals(other);
+        }
+
+        public override int GetHashCode()
+        {
+            return GlobalContext.GetHashCode()
+                ^ (LocalContext.GetHashCode() * 31);
+        }
     }
 }