Merge pull request #19875 from CyrusNajmabadi/lessAllocations2

Reduce allocations in IsGeneratedSymbolWithGeneratedCodeAttribute.

src/Compilers/Core/Portable/InternalUtilities/GeneratedCodeUtilities.cs

@@ -8,16 +8,21 @@
 
 namespace Roslyn.Utilities
 {
-        internal static class GeneratedCodeUtilities
+    internal static class GeneratedCodeUtilities
+    {
+        private static readonly string[] s_autoGeneratedStrings = new[] { "<autogenerated", "<auto-generated" };
+
+        internal static bool IsGeneratedSymbolWithGeneratedCodeAttribute(
+            ISymbol symbol, INamedTypeSymbol generatedCodeAttribute)
         {
-            private static readonly string[] s_autoGeneratedStrings = new[] { "<autogenerated", "<auto-generated" };
+            Debug.Assert(symbol != null);
+            Debug.Assert(generatedCodeAttribute != null);
 
-            internal static bool IsGeneratedSymbolWithGeneratedCodeAttribute(
-                ISymbol symbol, INamedTypeSymbol generatedCodeAttribute)
+            // Don't check this for namespaces.  Namespaces cannot have attributes on them. And, 
+            // currently, calling DeclaringSyntaxReferences on an INamespaceSymbol is more expensive
+            // than is desirable.
+            if (symbol.Kind != SymbolKind.Namespace)
             {
-                Debug.Assert(symbol != null);
-                Debug.Assert(generatedCodeAttribute != null);
-
                 // GeneratedCodeAttribute can only be applied once on a symbol.
                 // For partial symbols with more than one definition, we must treat them as non-generated code symbols.
                 if (symbol.DeclaringSyntaxReferences.Length > 1)
@@ -25,77 +30,81 @@ internal static class GeneratedCodeUtilities
                     return false;
                 }
 
-                if (symbol.GetAttributes().Any(a => a.AttributeClass == generatedCodeAttribute))
+                foreach (var attribute in symbol.GetAttributes())
                 {
-                    return true;
+                    if (generatedCodeAttribute.Equals(attribute.AttributeClass))
+                    {
+                        return true;
+                    }
                 }
-
-                return symbol.ContainingSymbol != null && IsGeneratedSymbolWithGeneratedCodeAttribute(symbol.ContainingSymbol, generatedCodeAttribute);
             }
 
-            internal static bool IsGeneratedCode(
-                SyntaxTree tree, Func<SyntaxTrivia, bool> isComment, CancellationToken cancellationToken)
-            {
-                return IsGeneratedCodeFile(tree.FilePath) ||
-                       BeginsWithAutoGeneratedComment(tree, isComment, cancellationToken);
-            }
+            return symbol.ContainingSymbol != null && IsGeneratedSymbolWithGeneratedCodeAttribute(symbol.ContainingSymbol, generatedCodeAttribute);
+        }
 
-            private static bool IsGeneratedCodeFile(string filePath)
+        internal static bool IsGeneratedCode(
+            SyntaxTree tree, Func<SyntaxTrivia, bool> isComment, CancellationToken cancellationToken)
+        {
+            return IsGeneratedCodeFile(tree.FilePath) ||
+                   BeginsWithAutoGeneratedComment(tree, isComment, cancellationToken);
+        }
+
+        private static bool IsGeneratedCodeFile(string filePath)
+        {
+            if (!string.IsNullOrEmpty(filePath))
             {
-                if (!string.IsNullOrEmpty(filePath))
+                var fileName = PathUtilities.GetFileName(filePath);
+                if (fileName.StartsWith("TemporaryGeneratedFile_", StringComparison.OrdinalIgnoreCase))
                 {
-                    var fileName = PathUtilities.GetFileName(filePath);
-                    if (fileName.StartsWith("TemporaryGeneratedFile_", StringComparison.OrdinalIgnoreCase))
-                    {
-                        return true;
-                    }
+                    return true;
+                }
 
-                    var extension = PathUtilities.GetExtension(fileName);
-                    if (!string.IsNullOrEmpty(extension))
+                var extension = PathUtilities.GetExtension(fileName);
+                if (!string.IsNullOrEmpty(extension))
+                {
+                    var fileNameWithoutExtension = PathUtilities.GetFileName(filePath, includeExtension: false);
+                    if (fileNameWithoutExtension.EndsWith(".designer", StringComparison.OrdinalIgnoreCase) ||
+                        fileNameWithoutExtension.EndsWith(".generated", StringComparison.OrdinalIgnoreCase) ||
+                        fileNameWithoutExtension.EndsWith(".g", StringComparison.OrdinalIgnoreCase) ||
+                        fileNameWithoutExtension.EndsWith(".g.i", StringComparison.OrdinalIgnoreCase))
                     {
-                        var fileNameWithoutExtension = PathUtilities.GetFileName(filePath, includeExtension: false);
-                        if (fileNameWithoutExtension.EndsWith(".designer", StringComparison.OrdinalIgnoreCase) ||
-                            fileNameWithoutExtension.EndsWith(".generated", StringComparison.OrdinalIgnoreCase) ||
-                            fileNameWithoutExtension.EndsWith(".g", StringComparison.OrdinalIgnoreCase) ||
-                            fileNameWithoutExtension.EndsWith(".g.i", StringComparison.OrdinalIgnoreCase))
-                        {
-                            return true;
-                        }
+                        return true;
                     }
                 }
-
-                return false;
             }
 
-            private static bool BeginsWithAutoGeneratedComment(
-                SyntaxTree tree, Func<SyntaxTrivia, bool> isComment, CancellationToken cancellationToken)
+            return false;
+        }
+
+        private static bool BeginsWithAutoGeneratedComment(
+            SyntaxTree tree, Func<SyntaxTrivia, bool> isComment, CancellationToken cancellationToken)
+        {
+            var root = tree.GetRoot(cancellationToken);
+            if (root.HasLeadingTrivia)
             {
-                var root = tree.GetRoot(cancellationToken);
-                if (root.HasLeadingTrivia)
-                {
-                    var leadingTrivia = root.GetLeadingTrivia();
+                var leadingTrivia = root.GetLeadingTrivia();
 
-                    foreach (var trivia in leadingTrivia)
+                foreach (var trivia in leadingTrivia)
+                {
+                    if (!isComment(trivia))
                     {
-                        if (!isComment(trivia))
-                        {
-                            continue;
-                        }
+                        continue;
+                    }
 
-                        var text = trivia.ToString();
+                    var text = trivia.ToString();
 
-                        // Check to see if the text of the comment contains an auto generated comment.
-                        foreach (var autoGenerated in s_autoGeneratedStrings)
+                    // Check to see if the text of the comment contains an auto generated comment.
+                    foreach (var autoGenerated in s_autoGeneratedStrings)
+                    {
+                        if (text.Contains(autoGenerated))
                         {
-                            if (text.Contains(autoGenerated))
-                            {
-                                return true;
-                            }
+                            return true;
                         }
                     }
                 }
-
-                return false;
             }
+
+            return false;
         }
+    }
 }
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