[Xamarin.Android.Tools.Bytecode] MethodParameters Attribute parsing (#107)

jonpryor · web-flow · commit 4273e5cee65c · 2017-01-03T13:20:18.000-05:00
Fixes: #106 Java 8 adds support for a `javac -parameters` option, which adds a `MethodParameters` attribute to the `.class` file. The `MethodParameters` attribute blob contains *reliable* parameter names, including for abstract methods and interface methods, unlike existing `LocalVariableTable`, which only exists for `javac -g` builds, and only for methods with *bodies*, i.e. *not* abstract methods and interface methods. Add support for parsing the `MethodParameters` attribute blob.
diff --git a/src/Xamarin.Android.Tools.Bytecode/AttributeInfo.cs b/src/Xamarin.Android.Tools.Bytecode/AttributeInfo.cs
@@ -42,6 +42,7 @@ public class AttributeInfo {
 		public  const   string  Exceptions              = "Exceptions";
 		public  const   string  InnerClasses            = "InnerClasses";
 		public  const   string  LocalVariableTable      = "LocalVariableTable";
+		public  const   string  MethodParameters        = "MethodParameters";
 		public  const   string  Signature               = "Signature";
 		public  const   string  StackMapTable           = "StackMapTable";
 
@@ -71,6 +72,7 @@ public string Name {
 			{ typeof (ExceptionsAttribute),             Exceptions },
 			{ typeof (InnerClassesAttribute),           InnerClasses },
 			{ typeof (LocalVariableTableAttribute),     LocalVariableTable },
+			{ typeof (MethodParametersAttribute),       MethodParameters },
 			{ typeof (SignatureAttribute),              Signature },
 			{ typeof (StackMapTableAttribute),          StackMapTable },
 		};
@@ -101,6 +103,7 @@ static AttributeInfo CreateAttribute (string name, ConstantPool constantPool, us
 			case Exceptions:            return new ExceptionsAttribute (constantPool, nameIndex, stream);
 			case InnerClasses:          return new InnerClassesAttribute (constantPool, nameIndex, stream);
 			case LocalVariableTable:    return new LocalVariableTableAttribute (constantPool, nameIndex, stream);
+			case MethodParameters:      return new MethodParametersAttribute (constantPool, nameIndex, stream);
 			case Signature:             return new SignatureAttribute (constantPool, nameIndex, stream);
 			case StackMapTable:         return new StackMapTableAttribute (constantPool, nameIndex, stream);
 			default:                    return new UnknownAttribute (constantPool, nameIndex, stream);
@@ -389,6 +392,74 @@ public override string ToString ()
 		}
 	}
 
+	public sealed class MethodParameterInfo {
+
+		internal    ushort                          nameIndex;
+		public      MethodParameterAccessFlags      AccessFlags;
+
+		public      ConstantPool                    ConstantPool {get; private set;}
+
+		public MethodParameterInfo (ConstantPool constantPool)
+		{
+			ConstantPool    = constantPool;
+		}
+
+		public string Name {
+			get {
+				if (nameIndex == 0)
+					return null;
+				return ((ConstantPoolUtf8Item) ConstantPool [nameIndex]).Value;
+			}
+		}
+
+		public override string ToString ()
+		{
+			return string.Format ("MethodParameterInfo(Name='{0}', AccessFlags={1})", Name, AccessFlags);
+		}
+	}
+
+	// https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.7.24
+	public sealed class MethodParametersAttribute : AttributeInfo {
+
+		List<MethodParameterInfo>   parameters;
+
+		public  IList<MethodParameterInfo>  ParameterInfo {
+			get {return parameters;}
+		}
+
+		public MethodParametersAttribute (ConstantPool constantPool, ushort nameIndex, Stream stream)
+			: base (constantPool, nameIndex, stream)
+		{
+			var length  = stream.ReadNetworkUInt32 ();
+			var count   = stream.ReadNetworkByte ();
+			Debug.Assert (
+					length == (checked ((count * 4) + 1)),
+					$"Unexpected `MethodParameters` length; expected {(count*4)+1}, got {length}!");
+			parameters  = new List<MethodParameterInfo> (count);
+			for (int i = 0; i < count; ++i) {
+				var pNameIndex  = stream.ReadNetworkUInt16 ();
+				var accessFlags = stream.ReadNetworkUInt16 ();
+				var p           = new MethodParameterInfo (constantPool) {
+					nameIndex   = pNameIndex,
+					AccessFlags = (MethodParameterAccessFlags) accessFlags,
+				};
+				parameters.Add (p);
+			}
+		}
+
+		public override string ToString ()
+		{
+			if (parameters.Count == 0)
+				return "MethodParametersAttribute()";
+			var sb = new StringBuilder ("MethodParametersAttribute(");
+			sb.Append (parameters [0]);
+			for (int i = 1; i < parameters.Count; ++i)
+				sb.Append (", ").Append (parameters [i]);
+			sb.Append (")");
+			return sb.ToString ();
+		}
+	}
+
 	// http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.7.9
 	public sealed class SignatureAttribute : AttributeInfo {
 
diff --git a/src/Xamarin.Android.Tools.Bytecode/Methods.cs b/src/Xamarin.Android.Tools.Bytecode/Methods.cs
@@ -132,6 +132,7 @@ public ParameterInfo[] GetParameters ()
 					parameters [i].Type.TypeSignature  = sig.Parameters [i];
 				}
 			}
+			UpdateParametersFromMethodParametersAttribute (parameters);
 			return parameters;
 		}
 
@@ -204,6 +205,33 @@ public MethodTypeSignature GetSignature ()
 				? new MethodTypeSignature (signature.Signature)
 				: null;
 		}
+
+		void UpdateParametersFromMethodParametersAttribute (ParameterInfo[] parameters)
+		{
+			var methodParams = (MethodParametersAttribute) Attributes.SingleOrDefault (a => a.Name == AttributeInfo.MethodParameters);
+			if (methodParams == null)
+				return;
+
+			const MethodParameterAccessFlags OuterThis =
+				MethodParameterAccessFlags.Mandated | MethodParameterAccessFlags.Final;
+			var pinfo = methodParams.ParameterInfo;
+			int startIndex = 0;
+			while (startIndex < pinfo.Count &&
+				   (pinfo [startIndex].AccessFlags & OuterThis) == OuterThis) {
+				startIndex++;
+			}
+			Debug.Assert (
+					parameters.Length == pinfo.Count - startIndex,
+					$"Unexpected number of method parameters; expected {parameters.Length}, got {pinfo.Count - startIndex}");
+			for (int i = 0; i < parameters.Length; ++i) {
+				var p = pinfo [i + startIndex];
+
+				parameters [i].AccessFlags = p.AccessFlags;
+				if (p != null) {
+					parameters [i].Name = p.Name;
+				}
+			}
+		}
 	}
 
 	public sealed class TypeInfo : IEquatable<TypeInfo> {
@@ -259,6 +287,8 @@ public sealed class ParameterInfo : IEquatable<ParameterInfo> {
 		public  int         Position;
 		public  TypeInfo    Type    = new TypeInfo ();
 
+		public  MethodParameterAccessFlags      AccessFlags;
+
 		public ParameterInfo (string name = null, string binaryName = null, string typeSignature = null, int position = 0)
 		{
 			Name                = name;
@@ -294,7 +324,7 @@ public bool Equals (ParameterInfo other)
 
 		public override string ToString ()
 		{
-			return string.Format ("ParameterInfo(Name={0}, Position={1}, Type={2}", Name, Position, Type);
+			return $"ParameterInfo(Name={Name}, Position={Position}, Type={Type}, AccessFlags={AccessFlags})";
 		}
 	}
 
@@ -313,4 +343,12 @@ public enum MethodAccessFlags {
 		Strict          = 0x0800,
 		Synthetic       = 0x1000,
 	}
+
+	[Flags]
+	public enum MethodParameterAccessFlags {
+		None,
+		Final           = 0x0010,
+		Synthetic       = 0x1000,
+		Mandated        = 0x8000,
+	}
 }
diff --git a/src/Xamarin.Android.Tools.Bytecode/Tests/IJavaInterface.xml b/src/Xamarin.Android.Tools.Bytecode/Tests/IJavaInterface.xml
@@ -50,7 +50,7 @@
         synthetic="false"
         jni-signature="(Ljava/lang/CharSequence;)Ljava/lang/Object;">
         <parameter
-          name="p0"
+          name="value"
           type="TString"
           jni-type="TTString;" />
       </method>
diff --git a/src/Xamarin.Android.Tools.Bytecode/Tests/IJavaInterfaceTests.cs b/src/Xamarin.Android.Tools.Bytecode/Tests/IJavaInterfaceTests.cs
@@ -18,7 +18,7 @@ public void ClassFile_WithIJavaInterface_class ()
 			new ExpectedTypeDeclaration {
 				MajorVersion        = 0x32,
 				MinorVersion        = 0,
-				ConstantPoolCount   = 21,
+				ConstantPoolCount   = 23,
 				AccessFlags         = ClassAccessFlags.Interface | ClassAccessFlags.Abstract,
 				FullName            = "com/xamarin/IJavaInterface",
 				Superclass          = new TypeInfo ("java/lang/Object", "Ljava/lang/Object;"),
@@ -61,7 +61,7 @@ public void ClassFile_WithIJavaInterface_class ()
 						ReturnDescriptor        = "Ljava/lang/Object;",
 						ReturnGenericDescriptor = "TTReturn;",
 						Parameters = {
-							new ParameterInfo ("p0",    "Ljava/lang/CharSequence;", "TTString;"),
+							new ParameterInfo ("value",     "Ljava/lang/CharSequence;", "TTString;"),
 						},
 					},
 				}
diff --git a/src/Xamarin.Android.Tools.Bytecode/Tests/JavaEnumTests.cs b/src/Xamarin.Android.Tools.Bytecode/Tests/JavaEnumTests.cs
@@ -22,7 +22,7 @@ public void ClassFileDescription ()
 			new ExpectedTypeDeclaration {
 				MajorVersion        = 0x32,
 				MinorVersion        = 0,
-				ConstantPoolCount   = 50,
+				ConstantPoolCount   = 53,
 				AccessFlags         = ClassAccessFlags.Final | ClassAccessFlags.Super | ClassAccessFlags.Enum,
 				FullName            = "com/xamarin/JavaEnum",
 				Superclass          = new TypeInfo ("java/lang/Enum",   "Ljava/lang/Enum<Lcom/xamarin/JavaEnum;>;"),
@@ -62,8 +62,8 @@ public void ClassFileDescription ()
 						AccessFlags             = MethodAccessFlags.Private,
 						ReturnDescriptor        = "V",
 						Parameters = {
-							new ParameterInfo ("p0", "Ljava/lang/String;",  "Ljava/lang/String;"),
-							new ParameterInfo ("p1", "I",                   "I"),
+							new ParameterInfo ("$enum$name",    "Ljava/lang/String;",  "Ljava/lang/String;"),
+							new ParameterInfo ("$enum$ordinal", "I",                   "I"),
 						},
 					},
 					new ExpectedMethodDeclaration {
diff --git a/src/Xamarin.Android.Tools.Bytecode/Tests/JavaType$RNC$RPNC.xml b/src/Xamarin.Android.Tools.Bytecode/Tests/JavaType$RNC$RPNC.xml
@@ -68,7 +68,7 @@
         synthetic="false"
         jni-signature="(Ljava/lang/Object;)Ljava/lang/Object;">
         <parameter
-          name="p0"
+          name="value"
           type="E2"
           jni-type="TE2;" />
       </method>
diff --git a/src/Xamarin.Android.Tools.Bytecode/Tests/JavaType$RNC.xml b/src/Xamarin.Android.Tools.Bytecode/Tests/JavaType$RNC.xml
@@ -64,7 +64,7 @@
         synthetic="false"
         jni-signature="(Ljava/lang/Object;)Ljava/lang/Object;">
         <parameter
-          name="p0"
+          name="value"
           type="E"
           jni-type="TE;" />
       </method>
diff --git a/src/Xamarin.Android.Tools.Bytecode/Tests/JavaType.RNC.RPNCTests.cs b/src/Xamarin.Android.Tools.Bytecode/Tests/JavaType.RNC.RPNCTests.cs
@@ -18,7 +18,7 @@ public void ClassFileDescription ()
 			new ExpectedTypeDeclaration {
 				MajorVersion        = 0x32,
 				MinorVersion        = 0,
-				ConstantPoolCount   = 44,
+				ConstantPoolCount   = 46,
 				AccessFlags         = ClassAccessFlags.Public | ClassAccessFlags.Super | ClassAccessFlags.Abstract,
 				FullName            = "com/xamarin/JavaType$RNC$RPNC",
 				Superclass          = new TypeInfo ("java/lang/Object", "Ljava/lang/Object;"),
@@ -71,7 +71,7 @@ public void ClassFileDescription ()
 						ReturnDescriptor        = "Ljava/lang/Object;",
 						ReturnGenericDescriptor = "TE3;",
 						Parameters = {
-							new ParameterInfo ("p0",    "Ljava/lang/Object;", "TE2;"),
+							new ParameterInfo ("value",     "Ljava/lang/Object;", "TE2;"),
 						},
 					},
 				}
diff --git a/src/Xamarin.Android.Tools.Bytecode/Tests/JavaType.RNCTests.cs b/src/Xamarin.Android.Tools.Bytecode/Tests/JavaType.RNCTests.cs
@@ -18,7 +18,7 @@ public void ClassFileDescription ()
 			new ExpectedTypeDeclaration {
 				MajorVersion        = 0x32,
 				MinorVersion        = 0,
-				ConstantPoolCount   = 42,
+				ConstantPoolCount   = 44,
 				AccessFlags         = ClassAccessFlags.Public | ClassAccessFlags.Super | ClassAccessFlags.Abstract,
 				FullName            = "com/xamarin/JavaType$RNC",
 				Superclass          = new TypeInfo ("java/lang/Object", "Ljava/lang/Object;"),
@@ -70,7 +70,7 @@ public void ClassFileDescription ()
 						ReturnDescriptor        = "Ljava/lang/Object;",
 						ReturnGenericDescriptor = "TE2;",
 						Parameters = {
-							new ParameterInfo ("p0",        "Ljava/lang/Object;",   "TE;"),
+							new ParameterInfo ("value",     "Ljava/lang/Object;",   "TE;"),
 						},
 					},
 				}
diff --git a/src/Xamarin.Android.Tools.Bytecode/Tests/JavaType.xml b/src/Xamarin.Android.Tools.Bytecode/Tests/JavaType.xml
@@ -110,7 +110,7 @@
         synthetic="true"
         jni-signature="(Ljava/lang/Object;)I">
         <parameter
-          name="p0"
+          name="value"
           type="java.lang.Object"
           jni-type="Ljava/lang/Object;" />
       </method>
@@ -162,7 +162,7 @@
         synthetic="true"
         jni-signature="(Ljava/lang/CharSequence;)Ljava/lang/Object;">
         <parameter
-          name="p0"
+          name="value"
           type="java.lang.CharSequence"
           jni-type="Ljava/lang/CharSequence;" />
       </method>
diff --git a/src/Xamarin.Android.Tools.Bytecode/Tests/JavaTypeTests.cs b/src/Xamarin.Android.Tools.Bytecode/Tests/JavaTypeTests.cs
@@ -20,7 +20,7 @@ public void ClassFile_WithJavaType_class ()
 			new ExpectedTypeDeclaration {
 				MajorVersion        = 0x32,
 				MinorVersion        = 0,
-				ConstantPoolCount   = 183,
+				ConstantPoolCount   = 184,
 				AccessFlags         = ClassAccessFlags.Public | ClassAccessFlags.Super,
 				FullName            = "com/xamarin/JavaType",
 				Superclass          = new TypeInfo ("java/lang/Object", "Ljava/lang/Object;"),
@@ -132,7 +132,7 @@ public void ClassFile_WithJavaType_class ()
 						Name                = "STATIC_FINAL_STRING",
 						Descriptor          = "Ljava/lang/String;",
 						AccessFlags         = FieldAccessFlags.Public | FieldAccessFlags.Static | FieldAccessFlags.Final,
-						ConstantValue       = "String(stringIndex=175 Utf8=\"Hello, \\\"embedded\0Nulls\" and \ud83d\udca9!\")",
+						ConstantValue       = "String(stringIndex=176 Utf8=\"Hello, \\\"embedded\0Nulls\" and \ud83d\udca9!\")",
 					},
 					new ExpectedFieldDeclaration {
 						Name                = "STATIC_FINAL_BOOL_FALSE",
@@ -309,15 +309,15 @@ public void ClassFile_WithJavaType_class ()
 						AccessFlags             = MethodAccessFlags.Public | MethodAccessFlags.Bridge | MethodAccessFlags.Synthetic,
 						ReturnDescriptor        = "I",
 						Parameters = {
-							new ParameterInfo ("p0", "Ljava/lang/Object;", "Ljava/lang/Object;"),
+							new ParameterInfo ("value", "Ljava/lang/Object;", "Ljava/lang/Object;"),
 						},
 					},
 					new ExpectedMethodDeclaration {
 						Name                    = "func",
 						AccessFlags             = MethodAccessFlags.Public | MethodAccessFlags.Bridge | MethodAccessFlags.Synthetic,
 						ReturnDescriptor        = "Ljava/lang/Object;",
 						Parameters = {
-							new ParameterInfo ("p0", "Ljava/lang/CharSequence;",    "Ljava/lang/CharSequence;"),
+							new ParameterInfo ("value", "Ljava/lang/CharSequence;", "Ljava/lang/CharSequence;"),
 						},
 					},
 					new ExpectedMethodDeclaration {
diff --git a/src/Xamarin.Android.Tools.Bytecode/Tests/Xamarin.Android.Tools.Bytecode-Tests.csproj b/src/Xamarin.Android.Tools.Bytecode/Tests/Xamarin.Android.Tools.Bytecode-Tests.csproj
@@ -56,7 +56,13 @@
     <Compile Include="ParameterFixupTests.cs" />
   </ItemGroup>
   <ItemGroup>
-    <TestJar Include="java\**\*.java" />
+    <TestJar
+        Include="java\**\*.java"
+        Exclude="java\java\util\Collection.java"
+    />
+    <TestJarNoParameters
+        Include="java\java\util\Collection.java"
+    />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <PropertyGroup>
@@ -67,7 +73,8 @@
   </PropertyGroup>
   <Target Name="BuildClasses" Inputs="@(TestJar)" Outputs="@(TestJar-&gt;'$(IntermediateOutputPath)classes\%(RecursiveDir)%(Filename).class')">
     <MakeDir Directories="$(IntermediateOutputPath)classes" />
-    <Exec Command="&quot;javac&quot; -source 1.5 -target 1.6 -g -d &quot;$(IntermediateOutputPath)classes&quot; @(TestJar -&gt; '%(Identity)', ' ')" />
+    <Exec Command="&quot;javac&quot; -parameters -source 1.5 -target 1.6 -g -d &quot;$(IntermediateOutputPath)classes&quot; @(TestJar->'%(Identity)', ' ')" />
+    <Exec Command="&quot;javac&quot; -source 1.5 -target 1.6 -g -d &quot;$(IntermediateOutputPath)classes&quot; @(TestJarNoParameters->'%(Identity)', ' ')" />
   </Target>
   <ItemGroup>
     <ProjectReference Include="..\Xamarin.Android.Tools.Bytecode.csproj">
