Distinguish positive and negative zeros in metadata writer.

Bug: https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems/edit/442050
CR: JKotas

[tfs-changeset: 1661975]

4 files changed, 63 insertions, 43 deletions

diff --git a/src/Common/src/Internal/Metadata/NativeFormat/Generator/SchemaDef.cs b/src/Common/src/Internal/Metadata/NativeFormat/Generator/SchemaDef.cs
index 54d049aa6..d5da54db8 100644
--- a/src/Common/src/Internal/Metadata/NativeFormat/Generator/SchemaDef.cs
+++ b/src/Common/src/Internal/Metadata/NativeFormat/Generator/SchemaDef.cs
@@ -26,25 +26,23 @@ public enum RecordDefFlags
 [Flags]
 public enum MemberDefFlags
 {
-    Map = 0x0001, // => Dictionary<string, RecordType> for MetadataWriter
-                  // => List<RecordType> for MetadataReader
-    List = 0x0002, // => List<RecordType>
-    Array = 0x0004, // => RecordType[]
+    Map = 0x0001,   // => List<RecordType> for writer
+    List = 0x0002,  // => List<RecordType> for writer
+    Array = 0x0004, // => RecordType[] for writer
 
     Collection = MemberDefFlags.Map | MemberDefFlags.List | MemberDefFlags.Array,
     Sequence = MemberDefFlags.List | MemberDefFlags.Array,
 
-    RecordRef = 0x0008, // => RecordTypeHandle
-
-    Ref = MemberDefFlags.RecordRef,
+    RecordRef = 0x0008,
 
     Child = 0x0010, // Member instance is logically defined and owned by record;
                     // otherwise instance may be shared (such as a TypeRef).
-    Name = 0x0020, // May be used as the member"s simple name for diagnostics.
+    Name = 0x0020, // May be used as the member's simple name for diagnostics.
     NotPersisted = 0x0040, // Indicates member is not written to or read from metadata.
     Compare = 0x0080, // Indicates member should be used for equality functionality.
     EnumerateForHashCode = 0x0100, // Indicates that the collection is safe to be enumerated in GetHashCode
                                    // without causing reentrancy
+    CustomCompare = 0x0200, // Indicates that this member uses a custom comparer
 }
 
 public enum MemberTypeKind
@@ -86,14 +84,14 @@ public class MemberDef
             else
             {
                 typeName = (kind == MemberTypeKind.WriterField) ? 
-                    (TypeName != null ? (string)TypeName : "MetadataRecord"): $"{ TypeName}Handle";
+                    (TypeName != null ? (string)TypeName : "MetadataRecord"): $"{TypeName}Handle";
             }
         }
         else
         {
             typeName = (string)TypeName;
         }
-        if ((Flags & (MemberDefFlags.Array | MemberDefFlags.List | MemberDefFlags.Map)) != 0)
+        if ((Flags & MemberDefFlags.Collection) != 0)
         {
             if (kind == MemberTypeKind.WriterField)
             {
@@ -119,10 +117,7 @@ public class MemberDef
         if (typeSet == null)
             return null;
 
-        string result = "One of: " + typeSet[0];
-        for (int i = 1; i < typeSet.Length; i++)
-            result += ", " + typeSet[i];
-        return result;
+        return "One of: " + String.Join(", ", typeSet);
     }
 }
 
@@ -161,14 +156,16 @@ public class EnumType
 
 public class PrimitiveType
 {
-    public PrimitiveType(string name, string typeName)
+    public PrimitiveType(string name, string typeName, bool customCompare = false)
     {
         Name = name;
         TypeName = typeName;
+        CustomCompare = customCompare;
     }
 
     readonly public string Name;
     readonly public string TypeName;
+    readonly public bool CustomCompare;
 }
 
 /// <summary>
@@ -208,8 +205,8 @@ class SchemaDef
         new PrimitiveType("uint", "UInt32"),
         new PrimitiveType("long", "Int64"),
         new PrimitiveType("ulong", "UInt64"),
-        new PrimitiveType("float", "Single"),
-        new PrimitiveType("double", "Double"),
+        new PrimitiveType("float", "Single", customCompare: true),
+        new PrimitiveType("double", "Double", customCompare: true),
     };
 
     // These enums supplement those defined by System.Reflection.Primitives.
@@ -292,7 +289,8 @@ class SchemaDef
                 new RecordDef(
                     name: "Constant" + primitiveType.TypeName + "Value",
                     members: new MemberDef[] {
-                        new MemberDef(name: "Value", typeName: primitiveType.Name)
+                        new MemberDef(name: "Value", typeName: primitiveType.Name,
+                            flags: primitiveType.CustomCompare ? MemberDefFlags.CustomCompare : 0)
                     }
                 )
         )
@@ -326,7 +324,8 @@ class SchemaDef
                 new RecordDef(
                     name: "Constant" + primitiveType.TypeName + "Array",
                     members: new MemberDef[] {
-                        new MemberDef(name: "Value", flags: MemberDefFlags.Array, typeName: primitiveType.TypeName)
+                        new MemberDef(name: "Value", typeName: primitiveType.TypeName,
+                            flags: MemberDefFlags.Array | (primitiveType.CustomCompare ? MemberDefFlags.CustomCompare : 0))
                     }
                 )
         )
@@ -782,9 +781,7 @@ class SchemaDef
             from member in r.Members
             let memberTypeName = member.TypeName as string
             where memberTypeName != null &&
-                ((member.Flags & MemberDefFlags.Array) != 0 ||
-                (member.Flags & MemberDefFlags.List) != 0 ||
-                (member.Flags & MemberDefFlags.Map) != 0) &&
+                (member.Flags & MemberDefFlags.Collection) != 0 &&
                 !PrimitiveTypes.Any(pt => pt.TypeName == memberTypeName)
             select memberTypeName
         ).Concat(new[] { "ScopeDefinition" }).Distinct().ToArray();
diff --git a/src/Common/src/Internal/Metadata/NativeFormat/Generator/WriterGen.cs b/src/Common/src/Internal/Metadata/NativeFormat/Generator/WriterGen.cs
index 25f18c15e..fe1daca06 100644
--- a/src/Common/src/Internal/Metadata/NativeFormat/Generator/WriterGen.cs
+++ b/src/Common/src/Internal/Metadata/NativeFormat/Generator/WriterGen.cs
@@ -61,14 +61,7 @@ class WriterGen : CsWriter
             if ((member.Flags & MemberDefFlags.RecordRef) == 0)
                 continue;
 
-            if ((member.Flags & (MemberDefFlags.Map | MemberDefFlags.Sequence)) != 0)
-            {
-                WriteLine($"{member.Name} = visitor.Visit(this, {member.Name});");
-            }
-            else
-            {
-                WriteLine($"{member.Name} = visitor.Visit(this, {member.Name});");
-            }
+            WriteLine($"{member.Name} = visitor.Visit(this, {member.Name});");
         }
         CloseScope("Visit");
 
@@ -94,17 +87,20 @@ class WriterGen : CsWriter
 
             if ((member.Flags & MemberDefFlags.Sequence) != 0)
             {
-                WriteLine($"if (!{member.Name}.SequenceEqual(other.{member.Name})) return false;");
+                if ((member.Flags & MemberDefFlags.CustomCompare) != 0)
+                    WriteLine($"if (!{member.Name}.SequenceEqual(other.{member.Name}, {member.TypeName}Comparer.Instance)) return false;");
+                else
+                    WriteLine($"if (!{member.Name}.SequenceEqual(other.{member.Name})) return false;");
             }
             else
-            if ((member.Flags & (MemberDefFlags.List | MemberDefFlags.Map)) != 0)
+            if ((member.Flags & (MemberDefFlags.Map | MemberDefFlags.RecordRef)) != 0)
             {
                 WriteLine($"if (!Object.Equals({member.Name}, other.{member.Name})) return false;");
             }
             else
-            if ((member.Flags & MemberDefFlags.RecordRef) != 0)
+            if ((member.Flags & MemberDefFlags.CustomCompare) != 0)
             {
-                WriteLine($"if (!Object.Equals({member.Name}, other.{member.Name})) return false;");
+                WriteLine($"if (!CustomComparer.Equals({member.Name}, other.{member.Name})) return false;");
             }
             else
             {
diff --git a/src/ILCompiler.MetadataWriter/src/Internal/Metadata/NativeFormat/Writer/NativeFormatWriterGen.cs b/src/ILCompiler.MetadataWriter/src/Internal/Metadata/NativeFormat/Writer/NativeFormatWriterGen.cs
index eee6cd3ea..d503e858e 100644
--- a/src/ILCompiler.MetadataWriter/src/Internal/Metadata/NativeFormat/Writer/NativeFormatWriterGen.cs
+++ b/src/ILCompiler.MetadataWriter/src/Internal/Metadata/NativeFormat/Writer/NativeFormatWriterGen.cs
@@ -676,7 +676,7 @@ namespace Internal.Metadata.NativeFormat.Writer
             if (Object.ReferenceEquals(this, obj)) return true;
             var other = obj as ConstantDoubleArray;
             if (other == null) return false;
-            if (!Value.SequenceEqual(other.Value)) return false;
+            if (!Value.SequenceEqual(other.Value, DoubleComparer.Instance)) return false;
             return true;
         } // Equals
 
@@ -745,7 +745,7 @@ namespace Internal.Metadata.NativeFormat.Writer
             if (Object.ReferenceEquals(this, obj)) return true;
             var other = obj as ConstantDoubleValue;
             if (other == null) return false;
-            if (Value != other.Value) return false;
+            if (!CustomComparer.Equals(Value, other.Value)) return false;
             return true;
         } // Equals
 
@@ -1527,7 +1527,7 @@ namespace Internal.Metadata.NativeFormat.Writer
             if (Object.ReferenceEquals(this, obj)) return true;
             var other = obj as ConstantSingleArray;
             if (other == null) return false;
-            if (!Value.SequenceEqual(other.Value)) return false;
+            if (!Value.SequenceEqual(other.Value, SingleComparer.Instance)) return false;
             return true;
         } // Equals
 
@@ -1596,7 +1596,7 @@ namespace Internal.Metadata.NativeFormat.Writer
             if (Object.ReferenceEquals(this, obj)) return true;
             var other = obj as ConstantSingleValue;
             if (other == null) return false;
-            if (Value != other.Value) return false;
+            if (!CustomComparer.Equals(Value, other.Value)) return false;
             return true;
         } // Equals
 
diff --git a/src/ILCompiler.MetadataWriter/src/Internal/Metadata/NativeFormat/Writer/NativeMetadataWriter.cs b/src/ILCompiler.MetadataWriter/src/Internal/Metadata/NativeFormat/Writer/NativeMetadataWriter.cs
index 0dec3aad3..5f486ab6d 100644
--- a/src/ILCompiler.MetadataWriter/src/Internal/Metadata/NativeFormat/Writer/NativeMetadataWriter.cs
+++ b/src/ILCompiler.MetadataWriter/src/Internal/Metadata/NativeFormat/Writer/NativeMetadataWriter.cs
@@ -2,8 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#pragma warning disable 649
-
 using System;
 using System.IO;
 using System.Collections.Generic;
@@ -567,7 +565,7 @@ namespace Internal.Metadata.NativeFormat.Writer
     /// </summary>
     public partial class ConstantStringValue
     {
-        public static explicit operator string (ConstantStringValue value)
+        public static explicit operator string(ConstantStringValue value)
         {
             if (value == null)
                 return null;
@@ -929,7 +927,7 @@ namespace Internal.Metadata.NativeFormat.Writer
                 ReturnType.ToString(false),
                 name
                     + (GenericParameterCount == 0 ? "" : "`" + GenericParameterCount.ToString())
-                    + "(" + String.Join(", ", Parameters.Select(p => p.ToString(false))) + 
+                    + "(" + String.Join(", ", Parameters.Select(p => p.ToString(false))) +
                     String.Join(", ", VarArgParameters.Select(p => p.ToString(false))) + ")"}.Where(e => !String.IsNullOrWhiteSpace(e)));
         }
     }
@@ -1120,5 +1118,34 @@ namespace Internal.Metadata.NativeFormat.Writer
             return true;
         }
     }
-}
 
+    // Distinguishes positive and negative zeros for float and double values
+    public static class CustomComparer
+    {
+        public static unsafe bool Equals(float x, float y)
+        {
+            return *(int*)&x == *(int*)&y;
+        }
+
+        public static bool Equals(double x, double y)
+        {
+            return BitConverter.DoubleToInt64Bits(x) == BitConverter.DoubleToInt64Bits(y);
+        }
+    }
+
+    public sealed class SingleComparer : IEqualityComparer<float>
+    {
+        public static readonly SingleComparer Instance = new SingleComparer();
+
+        public bool Equals(float x, float y) => CustomComparer.Equals(x, y);
+        public int GetHashCode(float obj) => obj.GetHashCode();
+    }
+
+    public sealed class DoubleComparer : IEqualityComparer<double>
+    {
+        public static readonly DoubleComparer Instance = new DoubleComparer();
+
+        public bool Equals(double x, double y) => CustomComparer.Equals(x, y);
+        public int GetHashCode(double obj) => obj.GetHashCode();
+    }
+}