2005-09-08 Martin Baulig <martin@ximian.com>

* interfaces/ITargetObject.cs (ITargetObject.IsNull): New property. * interfaces/ILanguage.cs (ILanguage.CreateNullObject): New method. * backends/mono/MonoNullObject.cs: New file. * backends/mono/MonoVariable.cs (MonoVariable.GetObject): Return a `MonoNullObject' if the location is null. * frontend/CSharpExpressionParser.jay (constant): Added `NULL'. * frontend/Expression.cs (NullExpression): New expression. * test/TestNull.cs, test/mono-debugger.test/TestNull.exp: Added tests for `null' handling. svn path=/trunk/debugger/; revision=49701
mono · Sep 8, 2005 · 12e3a24 · 12e3a24
1 parent d8da200
commit 12e3a24
Show file tree

Hide file tree

Showing 23 changed files with 249 additions and 22 deletions.
diff --git a/ChangeLog b/ChangeLog
@@ -1,3 +1,23 @@
+2005-09-08  Martin Baulig  <martin@ximian.com>
+
+	* interfaces/ITargetObject.cs
+	(ITargetObject.IsNull): New property.
+
+	* interfaces/ILanguage.cs
+	(ILanguage.CreateNullObject): New method.
+
+	* backends/mono/MonoNullObject.cs: New file.
+
+	* backends/mono/MonoVariable.cs (MonoVariable.GetObject): Return a
+	`MonoNullObject' if the location is null.
+
+	* frontend/CSharpExpressionParser.jay (constant): Added `NULL'.
+
+	* frontend/Expression.cs (NullExpression): New expression.
+
+	* test/TestNull.cs, test/mono-debugger.test/TestNull.exp: Added
+	tests for `null' handling.
+
 2005-09-08  Martin Baulig  <martin@ximian.com>
 
 	* interfaces/ITargetArrayObject.cs (ITargetArrayObject.this): Take

diff --git a/backends/Inferior.cs b/backends/Inferior.cs
@@ -641,33 +641,49 @@ public long ReadLongInteger (TargetAddress address)
 		public TargetAddress ReadAddress (TargetAddress address)
 		{
 			check_disposed ();
+			TargetAddress res;
 			switch (TargetAddressSize) {
 			case 4:
-				return new TargetAddress (AddressDomain, (uint) ReadInteger (address));
+				res = new TargetAddress (AddressDomain, (uint) ReadInteger (address));
+				break;
 
 			case 8:
-				return new TargetAddress (AddressDomain, ReadLongInteger (address));
+				res = new TargetAddress (AddressDomain, ReadLongInteger (address));
+				break;
 
 			default:
 				throw new TargetMemoryException (
 					"Unknown target address size " + TargetAddressSize);
 			}
+
+			if (res.Address == 0)
+				return TargetAddress.Null;
+			else
+				return res;
 		}
 
 		public TargetAddress ReadGlobalAddress (TargetAddress address)
 		{
 			check_disposed ();
+			TargetAddress res;
 			switch (TargetAddressSize) {
 			case 4:
-				return new TargetAddress (GlobalAddressDomain, (uint) ReadInteger (address));
+				res = new TargetAddress (GlobalAddressDomain, (uint) ReadInteger (address));
+				break;
 
 			case 8:
-				return new TargetAddress (GlobalAddressDomain, ReadLongInteger (address));
+				res = new TargetAddress (GlobalAddressDomain, ReadLongInteger (address));
+				break;
 
 			default:
 				throw new TargetMemoryException (
 					"Unknown target address size " + TargetAddressSize);
 			}
+
+			if (res.Address == 0)
+				return TargetAddress.Null;
+			else
+				return res;
 		}
 
 		public string ReadString (TargetAddress address)

diff --git a/backends/classes/MonoVariableLocation.cs b/backends/classes/MonoVariableLocation.cs
@@ -37,8 +37,11 @@ void update ()
 
 			long contents = reg.Value;
 
-			address = new TargetAddress (
-				TargetMemoryInfo.AddressDomain, contents + regoffset);
+			if (contents == 0)
+				address = TargetAddress.Null;
+			else
+				address = new TargetAddress (
+					TargetMemoryInfo.AddressDomain, contents + regoffset);
 
 			if (is_byref && is_regoffset)
 				address = TargetMemoryAccess.ReadAddress (address);

diff --git a/backends/classes/TargetLocation.cs b/backends/classes/TargetLocation.cs
@@ -116,6 +116,9 @@ public virtual TargetAddress ReadAddress ()
 			else
 				throw new InternalError ();
 
+			if (address == 0)
+				return TargetAddress.Null;
+
 			return new TargetAddress (TargetMemoryInfo.AddressDomain, address);
 		}
 

diff --git a/backends/mono/MonoArrayObject.cs b/backends/mono/MonoArrayObject.cs
@@ -116,6 +116,9 @@ int GetArrayOffset (int[] indices)
 					dynamic_location.GetLocationAtOffset (
 						offset, type.Type.ElementType.IsByRef);
 
+				if (new_location.HasAddress && new_location.Address.IsNull)
+					return new MonoNullObject (type.ElementType, new_location);
+
 				return type.ElementType.GetObject (new_location);
 			}
 

diff --git a/backends/mono/MonoLanguageBackend.cs b/backends/mono/MonoLanguageBackend.cs
@@ -807,7 +807,7 @@ public ITargetPointerObject CreatePointer (StackFrame frame, TargetAddress addre
 
 		public ITargetObject CreateObject (ITargetAccess target, TargetAddress address)
 		{
-			TargetLocation location = new AbsoluteTargetLocation (null, target, address);
+			TargetLocation location = new AbsoluteTargetLocation (target, address);
 			MonoObjectObject obj = (MonoObjectObject)builtin_types.ObjectType.GetTypeInfo().GetObject (location);
 			if (obj == null)
 				return null;
@@ -818,6 +818,17 @@ public ITargetObject CreateObject (ITargetAccess target, TargetAddress address)
 				return obj;
 		}
 
+		public ITargetObject CreateNullObject (ITargetAccess target, ITargetType type)
+		{
+			TargetLocation location = new AbsoluteTargetLocation (target, TargetAddress.Null);
+
+			IMonoTypeInfo tinfo = ((MonoType) type).GetTypeInfo ();
+			if (tinfo == null)
+				tinfo = builtin_types.ObjectType;
+
+			return new MonoNullObject (tinfo, location);
+		}
+
 		ITargetFundamentalType ILanguage.IntegerType {
 			get { return builtin_types.Int32Type; }
 		}

diff --git a/backends/mono/MonoNullObject.cs b/backends/mono/MonoNullObject.cs
@@ -0,0 +1,17 @@
+using System;
+
+namespace Mono.Debugger.Languages.Mono
+{
+	internal class MonoNullObject : MonoObject
+	{
+		public MonoNullObject (IMonoTypeInfo type, TargetLocation location)
+			: base (type, location)
+		{ }
+
+		protected override long GetDynamicSize (TargetBlob blob, TargetLocation location,
+							out TargetLocation dynamic_location)
+		{
+			throw new InvalidOperationException ();
+		}
+	}
+}
diff --git a/backends/mono/MonoObject.cs b/backends/mono/MonoObject.cs
@@ -41,7 +41,16 @@ public MonoObject (IMonoTypeInfo type_info, TargetLocation location)
 
 		public bool IsValid {
 			get {
-				return is_valid && (location != null);
+				return is_valid;
+			}
+		}
+
+		public bool IsNull {
+			get {
+				if (!location.HasAddress)
+					return false;
+				else
+					return location.Address.IsNull;
 			}
 		}
 

diff --git a/backends/mono/MonoStringObject.cs b/backends/mono/MonoStringObject.cs
@@ -42,6 +42,8 @@ protected override object GetObject (TargetBlob blob, TargetLocation location)
 
 		public override string Print ()
 		{
+			if (location.Address.IsNull)
+				return "null";
 			object obj = GetObject ();
 			return '"' + (string) obj + '"';
 		}

diff --git a/backends/mono/MonoVariable.cs b/backends/mono/MonoVariable.cs
@@ -120,6 +120,10 @@ public ITargetObject GetObject (StackFrame frame)
 			if (location == null)
 				throw new LocationInvalidException ();
 
+			if (location.HasAddress && location.Address.IsNull)
+				return backend.MonoLanguage.CreateNullObject (
+					frame.TargetAccess, type);
+
 			IMonoTypeInfo tinfo = type.GetTypeInfo ();
 			if (tinfo == null)
 				return null;

diff --git a/backends/native/NativeLanguage.cs b/backends/native/NativeLanguage.cs
@@ -79,7 +79,12 @@ public ITargetFundamentalObject CreateInstance (ITargetAccess target, int value)
 
 		public ITargetObject CreateObject (ITargetAccess target, TargetAddress address)
 		{
-			return null;
+			throw new NotSupportedException ();
+		}
+
+		public ITargetObject CreateNullObject (ITargetAccess target, ITargetType type)
+		{
+			throw new NotSupportedException ();
 		}
 
 		private bool disposed = false;

diff --git a/backends/native/NativeObject.cs b/backends/native/NativeObject.cs
@@ -35,7 +35,16 @@ public NativeObject (ITargetType type, TargetLocation location)
 
 		public bool IsValid {
 			get {
-				return is_valid && (location != null);
+				return is_valid;
+			}
+		}
+
+		public bool IsNull {
+			get {
+				if (!location.HasAddress)
+					return false;
+				else
+					return location.Address.IsNull;
 			}
 		}
 

diff --git a/classes/TargetMemoryException.cs b/classes/TargetMemoryException.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Runtime.Serialization;
 
 namespace Mono.Debugger
 {
@@ -21,6 +22,16 @@ public TargetMemoryException (TargetAddress address, int size)
 			: this (String.Format ("Cannot read {1} bytes from target memory at address {0:x}",
 					       address, size))
 		{ }
+
+		protected TargetMemoryException (SerializationInfo info, StreamingContext context)
+			: base (info, context)
+		{
+		}
+
+                public override void GetObjectData (SerializationInfo info, StreamingContext context)
+		{
+			base.GetObjectData (info, context);
+		}
 	}
 
 	[Serializable]
@@ -34,5 +45,15 @@ public TargetMemoryReadOnlyException (TargetAddress address)
 			: base (String.Format ("Can't write to target memory at address 0x{0:x}: {1}",
 					       address, "the current target's memory is read-only"))
 		{ }
+
+		protected TargetMemoryReadOnlyException (SerializationInfo info, StreamingContext context)
+			: base (info, context)
+		{
+		}
+
+                public override void GetObjectData (SerializationInfo info, StreamingContext context)
+		{
+			base.GetObjectData (info, context);
+		}
 	}
 }
diff --git a/frontend/CSharpExpressionParser.jay b/frontend/CSharpExpressionParser.jay
@@ -150,11 +150,15 @@ constant
 	{
 		$$ = new NumberExpression ((decimal) $1);
 	}
-
 	| STRING
 	  {
 		$$ = new StringExpression ((string) $1);
 	  }
+	| NULL
+	  {
+		$$ = new NullExpression ();
+	  }
+	;
 
 expression
 	: constant

diff --git a/frontend/CSharpTokenizer.cs b/frontend/CSharpTokenizer.cs
@@ -71,7 +71,7 @@ static void InitTokens ()
 			keywords.Add ("false", Token.FALSE);
 			keywords.Add ("True", Token.TRUE);
 			keywords.Add ("False", Token.FALSE);
-			keywords.Add ("null", Token.FALSE);
+			keywords.Add ("null", Token.NULL);
 		}
 
 		public string error {

diff --git a/frontend/Expression.cs b/frontend/Expression.cs
@@ -363,6 +363,30 @@ protected override ITargetObject DoEvaluateVariable (ScriptingContext context)
 		}
 	}
 
+	public class NullExpression : Expression
+	{
+		public override string Name {
+			get { return "null"; }
+		}
+
+		protected override Expression DoResolve (ScriptingContext context)
+		{
+			resolved = true;
+			return this;
+		}
+
+		protected override object DoEvaluate (ScriptingContext context)
+		{
+			return null;
+		}
+
+		protected override ITargetObject DoEvaluateVariable (ScriptingContext context)
+		{
+			StackFrame frame = context.CurrentFrame.Frame;
+			return frame.Language.CreateObject (frame.TargetAccess, TargetAddress.Null);
+		}
+	}
+
 	public class ThisExpression : Expression
 	{
 		public override string Name {

diff --git a/frontend/ScriptingContext.cs b/frontend/ScriptingContext.cs
@@ -181,8 +181,6 @@ public ITargetObject GetVariable (IVariable var)
 		{
 			if (!var.IsAlive (frame.TargetAddress))
 				throw new ScriptingException ("Variable out of scope.");
-			if (!var.CheckValid (frame))
-				throw new ScriptingException ("Variable cannot be accessed.");
 
 			return var.GetObject (frame);
 		}

diff --git a/frontend/Style.cs b/frontend/Style.cs
@@ -413,6 +413,9 @@ protected string DoFormatObject (ITargetObject obj, bool recursed)
 
 		protected string DoFormatObjectRecursed (ITargetObject obj)
 		{
+			if (obj.IsNull)
+				return "null";
+
 			switch (obj.Kind) {
 			case TargetObjectKind.Class:
 			case TargetObjectKind.Struct:
@@ -460,6 +463,9 @@ protected string DoFormatArray (ITargetArrayObject aobj)
 
 		protected string DoFormatObject (ITargetObject obj)
 		{
+			if (obj.IsNull)
+				return "null";
+
 			switch (obj.Kind) {
 			case TargetObjectKind.Array:
 				return DoFormatArray ((ITargetArrayObject) obj);
@@ -505,22 +511,19 @@ protected string DoFormatObject (ITargetObject obj)
 
 		public override string PrintVariable (IVariable variable, StackFrame frame)
 		{
+			string contents;
 			ITargetObject obj = null;
-			try {
-				obj = variable.GetObject (frame);
-			} catch {
-			}
 
-			string contents;
 			try {
+				obj = variable.GetObject (frame);
 				if (obj != null)
 					contents = DoFormatObject (obj, false);
 				else
 					contents = "<cannot display object>";
 			} catch {
 				contents = "<cannot display object>";
 			}
-				
+
 			return String.Format (
 				"{0} = ({1}) {2}", variable.Name, variable.Type.Name, contents);
 		}

diff --git a/interfaces/ILanguage.cs b/interfaces/ILanguage.cs
@@ -41,6 +41,8 @@ public interface ILanguage : IDisposable
 		ITargetPointerObject CreatePointer (StackFrame frame, TargetAddress address);
 
 		ITargetObject CreateObject (ITargetAccess target, TargetAddress address);
+
+		ITargetObject CreateNullObject (ITargetAccess target, ITargetType type);
 	}
 }
 
diff --git a/interfaces/ITargetObject.cs b/interfaces/ITargetObject.cs
@@ -25,6 +25,10 @@ public interface ITargetObject
 			get;
 		}
 
+		bool IsNull {
+			get;
+		}
+
 		// <summary>
 		//   Returns the raw contents of this object.  For objects with dynamic size,
 		//   this returns a buffer of `Type.Size' bytes which is just enough to get