Spanify some Utf8String and Utf8StringBuilder use

src/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs

@@ -344,7 +344,7 @@ public override Utf8String GetMangledMethodName(MethodDesc method)
 
             Utf8StringBuilder sb = new Utf8StringBuilder();
             sb.Append(GetMangledTypeName(method.OwningType));
-            sb.Append("__");
+            sb.Append("__"u8);
             sb.Append(GetUnqualifiedMangledMethodName(method));
             utf8MangledName = sb.ToUtf8String();
 
@@ -391,7 +391,7 @@ private Utf8String GetPrefixMangledSignatureName(IPrefixMangledSignature prefixM
 
             for (int i = 0; i < signature.Length; i++)
             {
-                sb.Append("__");
+                sb.Append("__"u8);
                 string sigArgName = GetMangledTypeName(signature[i]);
                 sb.Append(sigArgName);
             }
@@ -451,7 +451,7 @@ private Utf8String ComputeUnqualifiedMangledMethodName(MethodDesc method)
                 {
                     string instArgName = GetMangledTypeName(inst[i]);
                     if (i > 0)
-                        sb.Append("__");
+                        sb.Append("__"u8);
                     sb.Append(instArgName);
                 }
 

src/coreclr/tools/Common/Internal/Text/Utf8String.cs

@@ -7,9 +7,9 @@
 
 namespace Internal.Text
 {
-    public struct Utf8String : IEquatable<Utf8String>, IComparable<Utf8String>
+    public readonly struct Utf8String : IEquatable<Utf8String>, IComparable<Utf8String>
     {
-        private byte[] _value;
+        private readonly byte[] _value;
 
         public Utf8String(byte[] underlyingArray)
         {
@@ -21,8 +21,6 @@ public Utf8String(string s)
             _value = Encoding.UTF8.GetBytes(s);
         }
 
-        // TODO: This should return ReadOnlySpan<byte> instead once available
-        public byte[] UnderlyingArray => _value;
         public int Length => _value.Length;
 
         // For now, define implicit conversions between string and Utf8String to aid the transition
@@ -32,14 +30,16 @@ public static implicit operator Utf8String(string s)
             return new Utf8String(s);
         }
 
+        public ReadOnlySpan<byte> AsSpan() => _value;
+
         public override string ToString()
         {
             return Encoding.UTF8.GetString(_value);
         }
 
         public override bool Equals(object obj)
         {
-            return (obj is Utf8String) && Equals((Utf8String)obj);
+            return (obj is Utf8String utf8String) && Equals(utf8String);
         }
 
         public override unsafe int GetHashCode()
@@ -72,67 +72,12 @@ public override unsafe int GetHashCode()
 
         public bool Equals(Utf8String other)
         {
-            int length = _value.Length;
-            if (length != other.Length)
-                return false;
-
-            if (_value == other._value)
-                return true;
-
-            unsafe
-            {
-                fixed (byte* ap = _value) fixed (byte* bp = other._value)
-                {
-                    byte* a = ap;
-                    byte* b = bp;
-
-                    while (length >= 4)
-                    {
-                        if (*(int*)a != *(int*)b) return false;
-                        a += 4; b += 4; length -= 4;
-                    }
-                    if (length >= 2)
-                    {
-                        if (*(short*)a != *(short*)b) return false;
-                        a += 2; b += 2; length -= 2;
-                    }
-                    if (length > 0)
-                    {
-                        if (*a != *b) return false;
-                    }
-                    return true;
-                }
-            }
+            return AsSpan().SequenceEqual(other.AsSpan());
         }
 
         private static int Compare(Utf8String strA, Utf8String strB)
         {
-            int length = Math.Min(strA.Length, strB.Length);
-
-            unsafe
-            {
-                fixed (byte* ap = strA._value)
-                fixed (byte* bp = strB._value)
-                {
-                    byte* a = ap;
-                    byte* b = bp;
-
-                    while (length > 0)
-                    {
-                        if (*a != *b)
-                            return *a - *b;
-                        a += 1;
-                        b += 1;
-                        length -= 1;
-                    }
-
-                    // At this point, we have compared all the characters in at least one string.
-                    // The longer string will be larger.
-                    // We could optimize and compare lengths before iterating strings, but we want
-                    // Foo and Foo1 to be sorted adjacent to eachother.
-                    return strA.Length - strB.Length;
-                }
-            }
+            return strA.AsSpan().SequenceCompareTo(strB.AsSpan());
         }
 
         public int CompareTo(Utf8String other)

src/coreclr/tools/Common/Internal/Text/Utf8StringBuilder.cs

@@ -16,10 +16,10 @@ public Utf8StringBuilder()
         {
         }
 
-        // TODO: This should return ReadOnlySpan<byte> instead once available
-        public byte[] UnderlyingArray => _buffer;
         public int Length => _length;
 
+        public ReadOnlySpan<byte> AsSpan() => _buffer.AsSpan(0, _length);
+
         public Utf8StringBuilder Clear()
         {
             _length = 0;
@@ -35,39 +35,31 @@ public Utf8StringBuilder Truncate(int newLength)
 
         public Utf8StringBuilder Append(Utf8String value)
         {
-            return Append(value.UnderlyingArray);
+            return Append(value.AsSpan());
         }
 
-        public Utf8StringBuilder Append(byte[] value)
+        public Utf8StringBuilder Append(ReadOnlySpan<byte> value)
         {
             Ensure(value.Length);
-            Buffer.BlockCopy(value, 0, _buffer, _length, value.Length);
+            value.CopyTo(_buffer.AsSpan(_length));
             _length += value.Length;
             return this;
         }
 
-        public Utf8StringBuilder Append(char value)
+        public Utf8StringBuilder Append(byte value)
         {
             Ensure(1);
-            if (value > 0x7F)
-                return Append(Encoding.UTF8.GetBytes(new char[] { value }));
-            _buffer[_length++] = (byte)value;
+            _buffer[_length++] = value;
             return this;
         }
 
         public Utf8StringBuilder Append(string value)
         {
-            Ensure(value.Length);
+            int length = Encoding.UTF8.GetByteCount(value);
+            Ensure(length);
 
-            byte[] buffer = _buffer;
-            for (int i = 0; i < value.Length; i++)
-            {
-                char c = value[i];
-                if (c > 0x7F)
-                    return Append(Encoding.UTF8.GetBytes(value));
-                buffer[_length+i] = (byte)c;
-            }
-            _length += value.Length;
+            Encoding.UTF8.GetBytes(value, _buffer.AsSpan(_length));
+            _length += length;
 
             return this;
         }
@@ -84,9 +76,7 @@ public string ToString(int start)
 
         public Utf8String ToUtf8String()
         {
-            var ret = new byte[_length];
-            Buffer.BlockCopy(_buffer, 0, ret, 0, _length);
-            return new Utf8String(ret);
+            return new Utf8String(_buffer.AsSpan(0, _length).ToArray());
         }
 
         private void Ensure(int extraSpace)
@@ -99,53 +89,8 @@ private void Grow(int extraSpace)
         {
             int newSize = Math.Max(2 * _buffer.Length, _length + extraSpace);
             byte[] newBuffer = new byte[newSize];
-            Buffer.BlockCopy(_buffer, 0, newBuffer, 0, _length);
+            _buffer.AsSpan(0, _length).CopyTo(newBuffer);
             _buffer = newBuffer;
         }
-
-        // Find the boundary of the last character prior to a position
-        // If pos points to the last byte of a char, then return pos; Otherwise,
-        // return the position of the last byte of the preceding char.
-        public int LastCharBoundary(int pos)
-        {
-            Debug.Assert(pos < _length);
-
-            if (_buffer[pos] < 128 /*10000000*/)
-            {
-                // This is a single byte character
-                return pos;
-            }
-
-            int origPos = pos;
-
-            // Skip following bytes of a multi-byte character until the first byte is seen
-            while (_buffer[pos] < 192 /*11000000*/)
-            {
-                pos--;
-            }
-
-            if (pos == origPos - 3)
-            {
-                // We just skipped a four-byte character
-                Debug.Assert(_buffer[pos] >= 240 /*11110000*/);
-                return origPos;
-            }
-
-            if (pos == origPos - 2 && _buffer[pos] < 240 && _buffer[pos] >= 224 /*11100000*/)
-            {
-                // We just skipped a three-byte character
-                return origPos;
-            }
-
-            if (pos == origPos - 1 && _buffer[pos] < 224)
-            {
-                // We just skipped a two-byte character
-                Debug.Assert(_buffer[pos] >= 192 /*11000000*/);
-                return origPos;
-            }
-
-            // We were in the middle of a multi-byte character
-            return pos - 1;
-        }
     }
 }

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DelegateCreationInfo.cs

@@ -306,20 +306,20 @@ public static DelegateCreationInfo Create(TypeDesc delegateType, MethodDesc targ
 
         public void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
         {
-            sb.Append("__DelegateCtor_");
+            sb.Append("__DelegateCtor_"u8);
             if (TargetNeedsVTableLookup)
-                sb.Append("FromVtbl_");
+                sb.Append("FromVtbl_"u8);
             Constructor.AppendMangledName(nameMangler, sb);
-            sb.Append("__");
+            sb.Append("__"u8);
             sb.Append(nameMangler.GetMangledMethodName(_targetMethod));
             if (_constrainedType != null)
             {
-                sb.Append("__");
+                sb.Append("__"u8);
                 nameMangler.GetMangledTypeName(_constrainedType);
             }
             if (Thunk != null)
             {
-                sb.Append("__");
+                sb.Append("__"u8);
                 Thunk.AppendMangledName(nameMangler, sb);
             }
         }

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/ArrayMapNode.cs

@@ -26,7 +26,7 @@ public ArrayMapNode(ExternalReferencesTableNode externalReferences)
 
         public void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
         {
-            sb.Append(nameMangler.CompilationUnitPrefix).Append("__array_type_map");
+            sb.Append(nameMangler.CompilationUnitPrefix).Append("__array_type_map"u8);
         }
         public int Offset => 0;
         public override bool IsShareable => false;

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/ArrayOfEmbeddedPointersNode.cs

@@ -114,7 +114,7 @@ public EmbeddedPointerIndirectionWithSymbolNode(ArrayOfEmbeddedPointersNode<TTar
 
             public override void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
             {
-                sb.Append(nameMangler.CompilationUnitPrefix).Append(_parentNode._startSymbolMangledName).Append("_").Append(_id.ToStringInvariant());
+                sb.Append(nameMangler.CompilationUnitPrefix).Append(_parentNode._startSymbolMangledName).Append("_"u8).Append(_id.ToStringInvariant());
             }
         }
     }

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/ArrayOfFrozenObjectsNode.cs

@@ -15,7 +15,7 @@ public class ArrayOfFrozenObjectsNode : DehydratableObjectNode, ISymbolDefinitio
         int INodeWithSize.Size => _size.Value;
 
         public void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
-            => sb.Append(nameMangler.CompilationUnitPrefix).Append("__FrozenSegmentStart");
+            => sb.Append(nameMangler.CompilationUnitPrefix).Append("__FrozenSegmentStart"u8);
 
         public int Offset => 0;
 

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/ByRefTypeMapNode.cs

@@ -25,7 +25,7 @@ public ByRefTypeMapNode(ExternalReferencesTableNode externalReferences)
 
         public void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
         {
-            sb.Append(nameMangler.CompilationUnitPrefix).Append("__byref_type_map");
+            sb.Append(nameMangler.CompilationUnitPrefix).Append("__byref_type_map"u8);
         }
         public int Offset => 0;
         public override bool IsShareable => false;

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/ClassConstructorContextMap.cs

@@ -25,7 +25,7 @@ public ClassConstructorContextMap(ExternalReferencesTableNode externalReferences
 
         public void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
         {
-            sb.Append(nameMangler.CompilationUnitPrefix).Append("__type_to_cctorContext_map");
+            sb.Append(nameMangler.CompilationUnitPrefix).Append("__type_to_cctorContext_map"u8);
         }
         public int Offset => 0;
 

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/DehydratedDataNode.cs

@@ -46,7 +46,7 @@ internal sealed class DehydratedDataNode : ObjectNode, ISymbolDefinitionNode, IN
 
         public void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
         {
-            sb.Append(nameMangler.CompilationUnitPrefix).Append("__dehydrated_data");
+            sb.Append(nameMangler.CompilationUnitPrefix).Append("__dehydrated_data"u8);
         }
 
         protected override string GetName(NodeFactory factory) => this.GetMangledName(factory.NameMangler);

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/DelegateMarshallingStubMapNode.cs

@@ -28,7 +28,7 @@ public DelegateMarshallingStubMapNode(ExternalReferencesTableNode externalRefere
 
         public void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
         {
-            sb.Append(nameMangler.CompilationUnitPrefix).Append("__delegate_marshalling_stub_map");
+            sb.Append(nameMangler.CompilationUnitPrefix).Append("__delegate_marshalling_stub_map"u8);
         }
         public int Offset => 0;
         public override bool IsShareable => false;

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/EETypeNode.cs

@@ -1469,7 +1469,7 @@ public override ObjectNodeSection GetSection(NodeFactory factory)
 
             public override bool StaticDependenciesAreComputed => true;
             public void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
-                => sb.Append("__writableData").Append(nameMangler.GetMangledTypeName(_type.Type));
+                => sb.Append("__writableData"u8).Append(nameMangler.GetMangledTypeName(_type.Type));
             public int Offset => 0;
             public override bool IsShareable => true;
             public override bool ShouldSkipEmittingObjectNode(NodeFactory factory) => _type.ShouldSkipEmittingObjectNode(factory);

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/EETypeOptionalFieldsNode.cs

@@ -26,7 +26,7 @@ public override ObjectNodeSection GetSection(NodeFactory factory)
 
         public void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
         {
-            sb.Append("__optionalfields_");
+            sb.Append("__optionalfields_"u8);
             _owner.AppendMangledName(nameMangler, sb);
         }
         public int Offset => 0;

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/EmbeddedPointerIndirectionNode.cs

@@ -49,7 +49,7 @@ public override void EncodeData(ref ObjectDataBuilder dataBuilder, NodeFactory f
 
         public virtual void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
         {
-            sb.Append("_embedded_ptr_");
+            sb.Append("_embedded_ptr_"u8);
             Target.AppendMangledName(nameMangler, sb);
         }
 

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/ExactMethodInstantiationsNode.cs

@@ -25,7 +25,7 @@ public ExactMethodInstantiationsNode(ExternalReferencesTableNode externalReferen
 
         public void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
         {
-            sb.Append(nameMangler.CompilationUnitPrefix).Append("__exact_method_instantiations");
+            sb.Append(nameMangler.CompilationUnitPrefix).Append("__exact_method_instantiations"u8);
         }
 
         int INodeWithSize.Size => _size.Value;

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/FrozenRuntimeTypeNode.cs

@@ -23,7 +23,7 @@ public FrozenRuntimeTypeNode(TypeDesc type, bool constructed)
 
         public override void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
         {
-            sb.Append(nameMangler.CompilationUnitPrefix).Append("__RuntimeType_").Append(nameMangler.GetMangledTypeName(_type));
+            sb.Append(nameMangler.CompilationUnitPrefix).Append("__RuntimeType_"u8).Append(nameMangler.GetMangledTypeName(_type));
         }
 
         protected override int ContentSize => ObjectType.InstanceByteCount.AsInt;