--- /dev/null
+//
+// block.cs: Block representation for the IL tree.
+//
+// Author:
+// Rafael Teixeira (rafaelteixeirabr@hotmail.com)
+// Miguel de Icaza (miguel@ximian.com)
+// Martin Baulig (martin@gnome.org)
+// Anirban Bhattacharjee (banirban@novell.com)
+// Manjula GHM (mmanjula@novell.com)
+// Satya Sudha K (ksathyasudha@novell.com)
+//
+// (C) 2001, 2002, 2003, 2004, 2005 Ximian, Inc.
+//
+
+using System;
+using System.Text;
+using System.Reflection;
+using System.Reflection.Emit;
+using System.Diagnostics;
+
+namespace Mono.MonoBASIC {
+
+ using System.Collections;
+
+ /// <summary>
+ /// Block represents a VB.NET block.
+ /// </summary>
+ ///
+ /// <remarks>
+ /// This class is used in a number of places: either to represent
+ /// explicit blocks that the programmer places or implicit blocks.
+ ///
+ /// Implicit blocks are used as labels or to introduce variable
+ /// declarations.
+ /// </remarks>
+ public class Block : Statement {
+ public readonly Block Parent;
+ public readonly bool Implicit;
+ public readonly Location StartLocation;
+ public Location EndLocation;
+
+ //
+ // The statements in this block
+ //
+ public ArrayList statements;
+
+ //
+ // An array of Blocks. We keep track of children just
+ // to generate the local variable declarations.
+ //
+ // Statements and child statements are handled through the
+ // statements.
+ //
+ ArrayList children;
+
+ //
+ // Labels. (label, block) pairs.
+ //
+ CaseInsensitiveHashtable labels;
+
+ //
+ // Keeps track of (name, type) pairs
+ //
+ CaseInsensitiveHashtable variables;
+
+ //
+ // Keeps track of constants
+ CaseInsensitiveHashtable constants;
+
+ //
+ // Maps variable names to ILGenerator.LocalBuilders
+ //
+ //CaseInsensitiveHashtable local_builders;
+
+ // to hold names of variables required for late binding
+ public const string lateBindingArgs = "1_LBArgs";
+ public const string lateBindingArgNames = "1_LBArgsNames";
+ public const string lateBindingCopyBack = "1_LBCopyBack";
+
+ bool isLateBindingRequired = false;
+
+ bool used = false;
+
+ static int id;
+
+ int this_id;
+
+ public Block (Block parent)
+ : this (parent, false, Location.Null, Location.Null)
+ { }
+
+ public Block (Block parent, bool implicit_block)
+ : this (parent, implicit_block, Location.Null, Location.Null)
+ { }
+
+ public Block (Block parent, bool implicit_block, Parameters parameters)
+ : this (parent, implicit_block, parameters, Location.Null, Location.Null)
+ { }
+
+ public Block (Block parent, Location start, Location end)
+ : this (parent, false, start, end)
+ { }
+
+ public Block (Block parent, Parameters parameters, Location start, Location end)
+ : this (parent, false, parameters, start, end)
+ { }
+
+ public Block (Block parent, bool implicit_block, Location start, Location end)
+ : this (parent, implicit_block, Parameters.EmptyReadOnlyParameters,
+ start, end)
+ { }
+
+ public Block (Block parent, bool implicit_block, Parameters parameters,
+ Location start, Location end)
+ {
+ if (parent != null)
+ parent.AddChild (this);
+ else {
+ // Top block
+ // Add variables that may be required for late binding
+ variables = new CaseInsensitiveHashtable ();
+ ArrayList rank_specifier = new ArrayList ();
+ ArrayList element = new ArrayList ();
+ element.Add (new EmptyExpression ());
+ rank_specifier.Add (element);
+ Expression e = Mono.MonoBASIC.Parser.DecomposeQI ("System.Object[]", start);
+ AddVariable (e, Block.lateBindingArgs, null, start);
+ e = Mono.MonoBASIC.Parser.DecomposeQI ("System.String[]", start);
+ AddVariable (e, Block.lateBindingArgNames, null, start);
+ e = Mono.MonoBASIC.Parser.DecomposeQI ("System.Boolean[]", start);
+ AddVariable (e, Block.lateBindingCopyBack, null, start);
+ }
+
+ this.Parent = parent;
+ this.Implicit = implicit_block;
+ this.parameters = parameters;
+ this.StartLocation = start;
+ this.EndLocation = end;
+ this.loc = start;
+ this_id = id++;
+ statements = new ArrayList ();
+ }
+
+ public bool IsLateBindingRequired {
+ get {
+ return isLateBindingRequired;
+ }
+ set {
+ isLateBindingRequired = value;
+ }
+ }
+
+ public int ID {
+ get {
+ return this_id;
+ }
+ }
+
+ void AddChild (Block b)
+ {
+ if (children == null)
+ children = new ArrayList ();
+
+ children.Add (b);
+ }
+
+ public void SetEndLocation (Location loc)
+ {
+ EndLocation = loc;
+ }
+
+ /// <summary>
+ /// Adds a label to the current block.
+ /// </summary>
+ ///
+ /// <returns>
+ /// false if the name already exists in this block. true
+ /// otherwise.
+ /// </returns>
+ ///
+/**
+ public bool AddLabel (string name, LabeledStatement target)
+ {
+ if (labels == null)
+ labels = new CaseInsensitiveHashtable ();
+ if (labels.Contains (name))
+ return false;
+
+ labels.Add (name, target);
+ return true;
+ }
+**/
+
+
+ public bool AddLabel (string name, LabeledStatement target, Location loc)
+ {
+/**
+ if (switch_block != null)
+ return switch_block.AddLabel (name, target, loc);
+**/
+ Block cur = this;
+ while (cur != null) {
+
+ if (cur.DoLookupLabel (name) != null) {
+ Report.Error (
+ 140, loc, "The label '" + name +"' is a duplicate");
+ return false;
+ }
+
+ if (!Implicit)
+ break;
+
+ cur = cur.Parent;
+ }
+
+ while (cur != null) {
+ if (cur.DoLookupLabel (name) != null) {
+ Report.Error (
+ 158, loc,
+ "The label '"+ name +"' shadows another label " +
+ "by the same name in a containing scope.");
+ return false;
+ }
+
+ if (children != null) {
+ foreach (Block b in children) {
+ LabeledStatement s = b.DoLookupLabel (name);
+ if (s == null)
+ continue;
+ Report.Error (
+ 158, s.Location,
+ "The label '"+ name +"' shadows another " +
+ "label by the same name in a " +
+ "containing scope.");
+ return false;
+ }
+ }
+ cur = cur.Parent;
+ }
+ if (labels == null)
+ labels = new CaseInsensitiveHashtable ();
+ if (labels.Contains (name))
+ return false;
+
+ labels.Add (name, target);
+ return true;
+
+ }
+
+ public LabeledStatement LookupLabel (string name)
+ {
+ LabeledStatement s = DoLookupLabel (name);
+ if (s != null)
+ return s;
+
+ if (children == null)
+ return null;
+
+ foreach (Block child in children) {
+ if (!child.Implicit)
+ continue;
+
+ s = child.LookupLabel (name);
+ if (s != null)
+ return s;
+ }
+
+ return null;
+ }
+
+ public LabeledStatement DoLookupLabel (string name)
+ {
+ if (labels != null){
+ if (labels.Contains (name))
+ return ((LabeledStatement) labels [name]);
+ }
+/**
+ if (Parent != null)
+ return Parent.LookupLabel (name);
+**/
+ return null;
+ }
+
+ VariableInfo this_variable = null;
+
+ // <summary>
+ // Returns the "this" instance variable of this block.
+ // See AddThisVariable() for more information.
+ // </summary>
+ public VariableInfo ThisVariable {
+ get {
+ if (this_variable != null)
+ return this_variable;
+ else if (Parent != null)
+ return Parent.ThisVariable;
+ else
+ return null;
+ }
+ }
+
+ Hashtable child_variable_names;
+
+ // <summary>
+ // Marks a variable with name @name as being used in a child block.
+ // If a variable name has been used in a child block, it's illegal to
+ // declare a variable with the same name in the current block.
+ // </summary>
+ public void AddChildVariableName (string name)
+ {
+ if (child_variable_names == null)
+ child_variable_names = new CaseInsensitiveHashtable ();
+
+ if (!child_variable_names.Contains (name))
+ child_variable_names.Add (name, true);
+ }
+
+ // <summary>
+ // Marks all variables from block @block and all its children as being
+ // used in a child block.
+ // </summary>
+ public void AddChildVariableNames (Block block)
+ {
+ if (block.Variables != null) {
+ foreach (string name in block.Variables.Keys)
+ AddChildVariableName (name);
+ }
+
+ foreach (Block child in block.children) {
+ if (child.Variables != null) {
+ foreach (string name in child.Variables.Keys)
+ AddChildVariableName (name);
+ }
+ }
+ }
+
+ // <summary>
+ // Checks whether a variable name has already been used in a child block.
+ // </summary>
+ public bool IsVariableNameUsedInChildBlock (string name)
+ {
+ if (child_variable_names == null)
+ return false;
+
+ return child_variable_names.Contains (name);
+ }
+
+ // <summary>
+ // This is used by non-static 'struct' constructors which do not have an
+ // initializer - in this case, the constructor must initialize all of the
+ // struct's fields. To do this, we add a "this" variable and use the flow
+ // analysis code to ensure that it's been fully initialized before control
+ // leaves the constructor.
+ // </summary>
+ public VariableInfo AddThisVariable (TypeContainer tc, Location l)
+ {
+ if (this_variable != null)
+ return this_variable;
+
+ this_variable = new VariableInfo (tc, ID, l);
+
+ if (variables == null)
+ variables = new CaseInsensitiveHashtable ();
+ variables.Add ("this", this_variable);
+
+ return this_variable;
+ }
+
+ public VariableInfo AddVariable (EmitContext ec, Expression type, string name, Location l)
+ {
+ if (!variables_initialized)
+ throw new InvalidOperationException();
+
+ VariableInfo vi = AddVariable(type, name, null, loc);
+
+ int priorCount = count_variables;
+ DeclSpace ds = ec.DeclSpace;
+
+ if (!vi.Resolve (ds)) {
+ vi.Number = -1;
+ } else {
+ vi.Number = ++count_variables;
+ if (vi.StructInfo != null)
+ count_variables += vi.StructInfo.Count;
+ }
+ if (priorCount < count_variables)
+ ec.CurrentBranching.CurrentUsageVector.AddExtraLocals(count_variables - priorCount);
+
+ return vi;
+ }
+
+ public VariableInfo AddVariable (Expression type, string name, Parameters pars, Location l)
+ {
+ if (variables == null)
+ variables = new CaseInsensitiveHashtable ();
+
+ VariableInfo vi = GetVariableInfo (name);
+ if (vi != null) {
+ if (vi.Block != ID)
+ Report.Error (30616, l, "A local variable named '" + name + "' " +
+ "cannot be declared in this scope since it would " +
+ "give a different meaning to '" + name + "', which " +
+ "is already used in a 'parent or current' scope to " +
+ "denote something else");
+ else
+ Report.Error (30290, l, "A local variable '" + name + "' is already " +
+ "defined in this scope");
+ return null;
+ }
+
+ if (IsVariableNameUsedInChildBlock (name)) {
+ Report.Error (136, l, "A local variable named '" + name + "' " +
+ "cannot be declared in this scope since it would " +
+ "give a different meaning to '" + name + "', which " +
+ "is already used in a 'child' scope to denote something " +
+ "else");
+ return null;
+ }
+
+ if (pars != null) {
+ int idx = 0;
+ Parameter p = pars.GetParameterByName (name, out idx);
+ if (p != null) {
+ Report.Error (30616, l, "A local variable named '" + name + "' " +
+ "cannot be declared in this scope since it would " +
+ "give a different meaning to '" + name + "', which " +
+ "is already used in a 'parent or current' scope to " +
+ "denote something else");
+ return null;
+ }
+ }
+
+ vi = new VariableInfo (type, name, ID, l);
+
+ variables.Add (name, vi);
+
+ return vi;
+ }
+
+ public bool AddConstant (Expression type, string name, Expression value, Parameters pars, Location l)
+ {
+ if (AddVariable (type, name, pars, l) == null)
+ return false;
+
+ if (constants == null)
+ constants = new CaseInsensitiveHashtable ();
+
+ constants.Add (name, value);
+ return true;
+ }
+
+ public Hashtable Variables {
+ get {
+ return variables;
+ }
+ }
+
+ public VariableInfo GetVariableInfo (string name)
+ {
+ if (variables != null) {
+ object temp;
+ temp = variables [name];
+
+ if (temp != null){
+ return (VariableInfo) temp;
+ }
+ }
+
+ if (Parent != null)
+ return Parent.GetVariableInfo (name);
+
+ return null;
+ }
+
+ public Expression GetVariableType (string name)
+ {
+ VariableInfo vi = GetVariableInfo (name);
+
+ if (vi != null)
+ return vi.Type;
+
+ return null;
+ }
+
+ public Expression GetConstantExpression (string name)
+ {
+ if (constants != null) {
+ object temp;
+ temp = constants [name];
+
+ if (temp != null)
+ return (Expression) temp;
+ }
+
+ if (Parent != null)
+ return Parent.GetConstantExpression (name);
+
+ return null;
+ }
+
+ /// <summary>
+ /// True if the variable named @name has been defined
+ /// in this block
+ /// </summary>
+ public bool IsVariableDefined (string name)
+ {
+ // Console.WriteLine ("Looking up {0} in {1}", name, ID);
+ if (variables != null) {
+ if (variables.Contains (name))
+ return true;
+ }
+
+ if (Parent != null)
+ return Parent.IsVariableDefined (name);
+
+ return false;
+ }
+
+ /// <summary>
+ /// True if the variable named @name is a constant
+ /// </summary>
+ public bool IsConstant (string name)
+ {
+ Expression e = null;
+
+ e = GetConstantExpression (name);
+
+ return e != null;
+ }
+
+ /// <summary>
+ /// Use to fetch the statement associated with this label
+ /// </summary>
+ public Statement this [string name] {
+ get {
+ return (Statement) labels [name];
+ }
+ }
+
+ Parameters parameters = null;
+ public Parameters Parameters {
+ get {
+ if (Parent != null)
+ return Parent.Parameters;
+
+ return parameters;
+ }
+ }
+
+ /// <returns>
+ /// A list of labels that were not used within this block
+ /// </returns>
+ public string [] GetUnreferenced ()
+ {
+ // FIXME: Implement me
+ return null;
+ }
+
+ public void AddStatement (Statement s)
+ {
+ statements.Add (s);
+ used = true;
+ }
+
+ public bool Used {
+ get {
+ return used;
+ }
+ }
+
+ public void Use ()
+ {
+ used = true;
+ }
+
+ bool variables_initialized = false;
+ int count_variables = 0, first_variable = 0;
+
+ void UpdateVariableInfo (EmitContext ec)
+ {
+ DeclSpace ds = ec.DeclSpace;
+
+ first_variable = 0;
+
+ if (Parent != null)
+ first_variable += Parent.CountVariables;
+
+ count_variables = first_variable;
+ if (variables != null) {
+ foreach (VariableInfo vi in variables.Values) {
+ if (!vi.Resolve (ds)) {
+ vi.Number = -1;
+ continue;
+ }
+
+ vi.Number = ++count_variables;
+
+ if (vi.StructInfo != null)
+ count_variables += vi.StructInfo.Count;
+ }
+ }
+
+ variables_initialized = true;
+ }
+
+ //
+ // <returns>
+ // The number of local variables in this block
+ // </returns>
+ public int CountVariables
+ {
+ get {
+ if (!variables_initialized)
+ throw new Exception ();
+
+ return count_variables;
+ }
+ }
+
+ /// <summary>
+ /// Emits the variable declarations and labels.
+ /// </summary>
+ /// <remarks>
+ /// tc: is our typecontainer (to resolve type references)
+ /// ig: is the code generator:
+ /// toplevel: the toplevel block. This is used for checking
+ /// that no two labels with the same name are used.
+ /// </remarks>
+ public void EmitMeta (EmitContext ec, Block toplevel)
+ {
+ //DeclSpace ds = ec.DeclSpace;
+ ILGenerator ig = ec.ig;
+
+ if (!variables_initialized)
+ UpdateVariableInfo (ec);
+
+ //
+ // Process this block variables
+ //
+ if (variables != null){
+ //local_builders = new CaseInsensitiveHashtable ();
+
+ foreach (DictionaryEntry de in variables){
+ string name = (string) de.Key;
+ /*
+ if (!isLateBindingRequired) {
+ if (name.Equals (Block.lateBindingArgs) ||
+ name.Equals (Block.lateBindingArgNames) ||
+ name.Equals (Block.lateBindingCopyBack))
+ continue;
+ }
+ */
+ VariableInfo vi = (VariableInfo) de.Value;
+
+ if (vi.VariableType == null)
+ continue;
+
+ vi.LocalBuilder = ig.DeclareLocal (vi.VariableType);
+
+ if (CodeGen.SymbolWriter != null)
+ vi.LocalBuilder.SetLocalSymInfo (name);
+
+ if (constants == null)
+ continue;
+
+ Expression cv = (Expression) constants [name];
+ if (cv == null)
+ continue;
+
+ Expression e = cv.Resolve (ec);
+ if (e == null)
+ continue;
+
+ if (!(e is Constant)){
+ Report.Error (133, vi.Location,
+ "The expression being assigned to '" +
+ name + "' must be constant (" + e + ")");
+ continue;
+ }
+
+ constants.Remove (name);
+ constants.Add (name, e);
+ }
+ }
+
+ //
+ // Now, handle the children
+ //
+ if (children != null){
+ foreach (Block b in children)
+ b.EmitMeta (ec, toplevel);
+ }
+ }
+
+ public void UsageWarning ()
+ {
+ string name;
+
+ if (variables != null){
+ foreach (DictionaryEntry de in variables){
+ VariableInfo vi = (VariableInfo) de.Value;
+
+ if (vi.Used)
+ continue;
+
+ name = (string) de.Key;
+
+ if (vi.Assigned){
+ Report.Warning (
+ 219, vi.Location, "The variable '" + name +
+ "' is assigned but its value is never used");
+ } else {
+ if (!(name.Equals(lateBindingArgs)||name.Equals(lateBindingArgNames)||name.Equals(lateBindingCopyBack)))
+ Report.Warning (
+ 168, vi.Location, "The variable '" +
+ name +"' is declared but never used");
+ }
+ }
+ }
+
+ if (children != null)
+ foreach (Block b in children)
+ b.UsageWarning ();
+ }
+
+ bool has_ret = false;
+
+ public override bool Resolve (EmitContext ec)
+ {
+ Block prev_block = ec.CurrentBlock;
+ bool ok = true;
+
+ ec.CurrentBlock = this;
+
+ if (!variables_initialized)
+ UpdateVariableInfo (ec);
+
+ ec.StartFlowBranching (this);
+
+ Report.Debug (1, "RESOLVE BLOCK", StartLocation, ec.CurrentBranching);
+
+ ArrayList new_statements = new ArrayList ();
+ bool unreachable = false, warning_shown = false;
+
+ foreach (Statement s in statements){
+
+ if (unreachable && !(s is LabeledStatement)) {
+ if (!warning_shown && !(s is EmptyStatement)) {
+ warning_shown = true;
+ Warning_DeadCodeFound (s.loc);
+ }
+ continue;
+ }
+
+ if (s.Resolve (ec) == false) {
+ ok = false;
+ continue;
+ }
+
+ if (s is LabeledStatement)
+ unreachable = false;
+ else
+ unreachable = ! ec.CurrentBranching.IsReachable ();
+
+ new_statements.Add (s);
+ }
+
+ statements = new_statements;
+
+ Report.Debug (1, "RESOLVE BLOCK DONE", StartLocation, ec.CurrentBranching);
+
+ FlowReturns returns = ec.EndFlowBranching ();
+ ec.CurrentBlock = prev_block;
+
+ // If we're a non-static 'struct' constructor which doesn't have an
+ // initializer, then we must initialize all of the struct's fields.
+ if ((this_variable != null) && (returns != FlowReturns.EXCEPTION) &&
+ !this_variable.IsAssigned (ec, loc))
+ ok = false;
+
+ if ((labels != null) && (RootContext.WarningLevel >= 2)) {
+ foreach (LabeledStatement label in labels.Values)
+ if (!label.HasBeenReferenced)
+ Report.Warning (164, label.Location,
+ "This label has not been referenced");
+ }
+
+ if ((returns == FlowReturns.ALWAYS) ||
+ (returns == FlowReturns.EXCEPTION) ||
+ (returns == FlowReturns.UNREACHABLE))
+ has_ret = true;
+
+ return ok;
+ }
+
+ protected override bool DoEmit (EmitContext ec)
+ {
+ Block prev_block = ec.CurrentBlock;
+
+ ec.CurrentBlock = this;
+
+ ec.Mark (StartLocation);
+ foreach (Statement s in statements)
+ s.Emit (ec);
+
+ ec.Mark (EndLocation);
+
+ ec.CurrentBlock = prev_block;
+ return has_ret;
+ }
+
+ public override string ToString ()
+ {
+ return String.Format ("{0} ({1}:{2})", GetType (),ID, StartLocation);
+ }
+
+ } // class Block
+
+} // namespace Mono.MonoBASIC
}
}
- /// <summary>
- /// Block represents a C# block.
- /// </summary>
- ///
- /// <remarks>
- /// This class is used in a number of places: either to represent
- /// explicit blocks that the programmer places or implicit blocks.
- ///
- /// Implicit blocks are used as labels or to introduce variable
- /// declarations.
- /// </remarks>
- public class Block : Statement {
- public readonly Block Parent;
- public readonly bool Implicit;
- public readonly Location StartLocation;
- public Location EndLocation;
-
- //
- // The statements in this block
- //
- public ArrayList statements;
-
- //
- // An array of Blocks. We keep track of children just
- // to generate the local variable declarations.
- //
- // Statements and child statements are handled through the
- // statements.
- //
- ArrayList children;
-
- //
- // Labels. (label, block) pairs.
- //
- CaseInsensitiveHashtable labels;
-
- //
- // Keeps track of (name, type) pairs
- //
- CaseInsensitiveHashtable variables;
-
- //
- // Keeps track of constants
- CaseInsensitiveHashtable constants;
-
- //
- // Maps variable names to ILGenerator.LocalBuilders
- //
- //CaseInsensitiveHashtable local_builders;
-
- // to hold names of variables required for late binding
- public const string lateBindingArgs = "1_LBArgs";
- public const string lateBindingArgNames = "1_LBArgsNames";
- public const string lateBindingCopyBack = "1_LBCopyBack";
-
- bool isLateBindingRequired = false;
-
- bool used = false;
-
- static int id;
-
- int this_id;
-
- public Block (Block parent)
- : this (parent, false, Location.Null, Location.Null)
- { }
-
- public Block (Block parent, bool implicit_block)
- : this (parent, implicit_block, Location.Null, Location.Null)
- { }
-
- public Block (Block parent, bool implicit_block, Parameters parameters)
- : this (parent, implicit_block, parameters, Location.Null, Location.Null)
- { }
-
- public Block (Block parent, Location start, Location end)
- : this (parent, false, start, end)
- { }
-
- public Block (Block parent, Parameters parameters, Location start, Location end)
- : this (parent, false, parameters, start, end)
- { }
-
- public Block (Block parent, bool implicit_block, Location start, Location end)
- : this (parent, implicit_block, Parameters.EmptyReadOnlyParameters,
- start, end)
- { }
-
- public Block (Block parent, bool implicit_block, Parameters parameters,
- Location start, Location end)
- {
- if (parent != null)
- parent.AddChild (this);
- else {
- // Top block
- // Add variables that may be required for late binding
- variables = new CaseInsensitiveHashtable ();
- ArrayList rank_specifier = new ArrayList ();
- ArrayList element = new ArrayList ();
- element.Add (new EmptyExpression ());
- rank_specifier.Add (element);
- Expression e = Mono.MonoBASIC.Parser.DecomposeQI ("System.Object[]", start);
- AddVariable (e, Block.lateBindingArgs, null, start);
- e = Mono.MonoBASIC.Parser.DecomposeQI ("System.String[]", start);
- AddVariable (e, Block.lateBindingArgNames, null, start);
- e = Mono.MonoBASIC.Parser.DecomposeQI ("System.Boolean[]", start);
- AddVariable (e, Block.lateBindingCopyBack, null, start);
- }
-
- this.Parent = parent;
- this.Implicit = implicit_block;
- this.parameters = parameters;
- this.StartLocation = start;
- this.EndLocation = end;
- this.loc = start;
- this_id = id++;
- statements = new ArrayList ();
- }
-
- public bool IsLateBindingRequired {
- get {
- return isLateBindingRequired;
- }
- set {
- isLateBindingRequired = value;
- }
- }
-
- public int ID {
- get {
- return this_id;
- }
- }
-
- void AddChild (Block b)
- {
- if (children == null)
- children = new ArrayList ();
-
- children.Add (b);
- }
-
- public void SetEndLocation (Location loc)
- {
- EndLocation = loc;
- }
-
- /// <summary>
- /// Adds a label to the current block.
- /// </summary>
- ///
- /// <returns>
- /// false if the name already exists in this block. true
- /// otherwise.
- /// </returns>
- ///
-/**
- public bool AddLabel (string name, LabeledStatement target)
- {
- if (labels == null)
- labels = new CaseInsensitiveHashtable ();
- if (labels.Contains (name))
- return false;
-
- labels.Add (name, target);
- return true;
- }
-**/
-
-
- public bool AddLabel (string name, LabeledStatement target, Location loc)
- {
-/**
- if (switch_block != null)
- return switch_block.AddLabel (name, target, loc);
-**/
- Block cur = this;
- while (cur != null) {
-
- if (cur.DoLookupLabel (name) != null) {
- Report.Error (
- 140, loc, "The label '" + name +"' is a duplicate");
- return false;
- }
-
- if (!Implicit)
- break;
-
- cur = cur.Parent;
- }
-
- while (cur != null) {
- if (cur.DoLookupLabel (name) != null) {
- Report.Error (
- 158, loc,
- "The label '"+ name +"' shadows another label " +
- "by the same name in a containing scope.");
- return false;
- }
-
- if (children != null) {
- foreach (Block b in children) {
- LabeledStatement s = b.DoLookupLabel (name);
- if (s == null)
- continue;
- Report.Error (
- 158, s.Location,
- "The label '"+ name +"' shadows another " +
- "label by the same name in a " +
- "containing scope.");
- return false;
- }
- }
- cur = cur.Parent;
- }
- if (labels == null)
- labels = new CaseInsensitiveHashtable ();
- if (labels.Contains (name))
- return false;
-
- labels.Add (name, target);
- return true;
-
- }
-
- public LabeledStatement LookupLabel (string name)
- {
- Block cur = this;
- LabeledStatement s = DoLookupLabel (name);
- if (s != null) {
- return s;
-}
- if (children == null)
- return null;
-
- foreach (Block child in children) {
- if (!child.Implicit)
- continue;
-
- s = child.LookupLabel (name);
- if (s != null) {
- cur = child;
- return s;
-}
- }
-
- return null;
- }
-
- public LabeledStatement DoLookupLabel (string name)
- {
- if (labels != null){
- if (labels.Contains (name))
- return ((LabeledStatement) labels [name]);
- }
-/**
- if (Parent != null)
- return Parent.LookupLabel (name);
-**/
- return null;
- }
-
- VariableInfo this_variable = null;
-
- // <summary>
- // Returns the "this" instance variable of this block.
- // See AddThisVariable() for more information.
- // </summary>
- public VariableInfo ThisVariable {
- get {
- if (this_variable != null)
- return this_variable;
- else if (Parent != null)
- return Parent.ThisVariable;
- else
- return null;
- }
- }
-
- Hashtable child_variable_names;
-
- // <summary>
- // Marks a variable with name @name as being used in a child block.
- // If a variable name has been used in a child block, it's illegal to
- // declare a variable with the same name in the current block.
- // </summary>
- public void AddChildVariableName (string name)
- {
- if (child_variable_names == null)
- child_variable_names = new CaseInsensitiveHashtable ();
-
- if (!child_variable_names.Contains (name))
- child_variable_names.Add (name, true);
- }
-
- // <summary>
- // Marks all variables from block @block and all its children as being
- // used in a child block.
- // </summary>
- public void AddChildVariableNames (Block block)
- {
- if (block.Variables != null) {
- foreach (string name in block.Variables.Keys)
- AddChildVariableName (name);
- }
-
- foreach (Block child in block.children) {
- if (child.Variables != null) {
- foreach (string name in child.Variables.Keys)
- AddChildVariableName (name);
- }
- }
- }
-
- // <summary>
- // Checks whether a variable name has already been used in a child block.
- // </summary>
- public bool IsVariableNameUsedInChildBlock (string name)
- {
- if (child_variable_names == null)
- return false;
-
- return child_variable_names.Contains (name);
- }
-
- // <summary>
- // This is used by non-static 'struct' constructors which do not have an
- // initializer - in this case, the constructor must initialize all of the
- // struct's fields. To do this, we add a "this" variable and use the flow
- // analysis code to ensure that it's been fully initialized before control
- // leaves the constructor.
- // </summary>
- public VariableInfo AddThisVariable (TypeContainer tc, Location l)
- {
- if (this_variable != null)
- return this_variable;
-
- this_variable = new VariableInfo (tc, ID, l);
-
- if (variables == null)
- variables = new CaseInsensitiveHashtable ();
- variables.Add ("this", this_variable);
-
- return this_variable;
- }
-
- public VariableInfo AddVariable (EmitContext ec, Expression type, string name, Location l)
- {
- if (!variables_initialized)
- throw new InvalidOperationException();
-
- VariableInfo vi = AddVariable(type, name, null, loc);
-
- int priorCount = count_variables;
- DeclSpace ds = ec.DeclSpace;
-
- if (!vi.Resolve (ds)) {
- vi.Number = -1;
- } else {
- vi.Number = ++count_variables;
- if (vi.StructInfo != null)
- count_variables += vi.StructInfo.Count;
- }
- if (priorCount < count_variables)
- ec.CurrentBranching.CurrentUsageVector.AddExtraLocals(count_variables - priorCount);
-
- return vi;
- }
-
- public VariableInfo AddVariable (Expression type, string name, Parameters pars, Location l)
- {
- if (variables == null)
- variables = new CaseInsensitiveHashtable ();
-
- VariableInfo vi = GetVariableInfo (name);
- if (vi != null) {
- if (vi.Block != ID)
- Report.Error (30616, l, "A local variable named '" + name + "' " +
- "cannot be declared in this scope since it would " +
- "give a different meaning to '" + name + "', which " +
- "is already used in a 'parent or current' scope to " +
- "denote something else");
- else
- Report.Error (30290, l, "A local variable '" + name + "' is already " +
- "defined in this scope");
- return null;
- }
-
- if (IsVariableNameUsedInChildBlock (name)) {
- Report.Error (136, l, "A local variable named '" + name + "' " +
- "cannot be declared in this scope since it would " +
- "give a different meaning to '" + name + "', which " +
- "is already used in a 'child' scope to denote something " +
- "else");
- return null;
- }
-
- if (pars != null) {
- int idx = 0;
- Parameter p = pars.GetParameterByName (name, out idx);
- if (p != null) {
- Report.Error (30616, l, "A local variable named '" + name + "' " +
- "cannot be declared in this scope since it would " +
- "give a different meaning to '" + name + "', which " +
- "is already used in a 'parent or current' scope to " +
- "denote something else");
- return null;
- }
- }
-
- vi = new VariableInfo (type, name, ID, l);
-
- variables.Add (name, vi);
-
- return vi;
- }
-
- public bool AddConstant (Expression type, string name, Expression value, Parameters pars, Location l)
- {
- if (AddVariable (type, name, pars, l) == null)
- return false;
-
- if (constants == null)
- constants = new CaseInsensitiveHashtable ();
-
- constants.Add (name, value);
- return true;
- }
-
- public Hashtable Variables {
- get {
- return variables;
- }
- }
-
- public VariableInfo GetVariableInfo (string name)
- {
- if (variables != null) {
- object temp;
- temp = variables [name];
-
- if (temp != null){
- return (VariableInfo) temp;
- }
- }
-
- if (Parent != null)
- return Parent.GetVariableInfo (name);
-
- return null;
- }
-
- public Expression GetVariableType (string name)
- {
- VariableInfo vi = GetVariableInfo (name);
-
- if (vi != null)
- return vi.Type;
-
- return null;
- }
-
- public Expression GetConstantExpression (string name)
- {
- if (constants != null) {
- object temp;
- temp = constants [name];
-
- if (temp != null)
- return (Expression) temp;
- }
-
- if (Parent != null)
- return Parent.GetConstantExpression (name);
-
- return null;
- }
-
- /// <summary>
- /// True if the variable named @name has been defined
- /// in this block
- /// </summary>
- public bool IsVariableDefined (string name)
- {
- // Console.WriteLine ("Looking up {0} in {1}", name, ID);
- if (variables != null) {
- if (variables.Contains (name))
- return true;
- }
-
- if (Parent != null)
- return Parent.IsVariableDefined (name);
-
- return false;
- }
-
- /// <summary>
- /// True if the variable named @name is a constant
- /// </summary>
- public bool IsConstant (string name)
- {
- Expression e = null;
-
- e = GetConstantExpression (name);
-
- return e != null;
- }
-
- /// <summary>
- /// Use to fetch the statement associated with this label
- /// </summary>
- public Statement this [string name] {
- get {
- return (Statement) labels [name];
- }
- }
-
- Parameters parameters = null;
- public Parameters Parameters {
- get {
- if (Parent != null)
- return Parent.Parameters;
-
- return parameters;
- }
- }
-
- /// <returns>
- /// A list of labels that were not used within this block
- /// </returns>
- public string [] GetUnreferenced ()
- {
- // FIXME: Implement me
- return null;
- }
-
- public void AddStatement (Statement s)
- {
- statements.Add (s);
- used = true;
- }
-
- public bool Used {
- get {
- return used;
- }
- }
-
- public void Use ()
- {
- used = true;
- }
-
- bool variables_initialized = false;
- int count_variables = 0, first_variable = 0;
-
- void UpdateVariableInfo (EmitContext ec)
- {
- DeclSpace ds = ec.DeclSpace;
-
- first_variable = 0;
-
- if (Parent != null)
- first_variable += Parent.CountVariables;
-
- count_variables = first_variable;
- if (variables != null) {
- foreach (VariableInfo vi in variables.Values) {
- if (!vi.Resolve (ds)) {
- vi.Number = -1;
- continue;
- }
-
- vi.Number = ++count_variables;
-
- if (vi.StructInfo != null)
- count_variables += vi.StructInfo.Count;
- }
- }
-
- variables_initialized = true;
- }
-
- //
- // <returns>
- // The number of local variables in this block
- // </returns>
- public int CountVariables
- {
- get {
- if (!variables_initialized)
- throw new Exception ();
-
- return count_variables;
- }
- }
-
- /// <summary>
- /// Emits the variable declarations and labels.
- /// </summary>
- /// <remarks>
- /// tc: is our typecontainer (to resolve type references)
- /// ig: is the code generator:
- /// toplevel: the toplevel block. This is used for checking
- /// that no two labels with the same name are used.
- /// </remarks>
- public void EmitMeta (EmitContext ec, Block toplevel)
- {
- //DeclSpace ds = ec.DeclSpace;
- ILGenerator ig = ec.ig;
-
- if (!variables_initialized)
- UpdateVariableInfo (ec);
-
- //
- // Process this block variables
- //
- if (variables != null){
- //local_builders = new CaseInsensitiveHashtable ();
-
- foreach (DictionaryEntry de in variables){
- string name = (string) de.Key;
- /*
- if (!isLateBindingRequired) {
- if (name.Equals (Block.lateBindingArgs) ||
- name.Equals (Block.lateBindingArgNames) ||
- name.Equals (Block.lateBindingCopyBack))
- continue;
- }
- */
- VariableInfo vi = (VariableInfo) de.Value;
-
- if (vi.VariableType == null)
- continue;
-
- vi.LocalBuilder = ig.DeclareLocal (vi.VariableType);
-
- if (CodeGen.SymbolWriter != null)
- vi.LocalBuilder.SetLocalSymInfo (name);
-
- if (constants == null)
- continue;
-
- Expression cv = (Expression) constants [name];
- if (cv == null)
- continue;
-
- Expression e = cv.Resolve (ec);
- if (e == null)
- continue;
-
- if (!(e is Constant)){
- Report.Error (133, vi.Location,
- "The expression being assigned to '" +
- name + "' must be constant (" + e + ")");
- continue;
- }
-
- constants.Remove (name);
- constants.Add (name, e);
- }
- }
-
- //
- // Now, handle the children
- //
- if (children != null){
- foreach (Block b in children)
- b.EmitMeta (ec, toplevel);
- }
- }
-
- public void UsageWarning ()
- {
- string name;
-
- if (variables != null){
- foreach (DictionaryEntry de in variables){
- VariableInfo vi = (VariableInfo) de.Value;
-
- if (vi.Used)
- continue;
-
- name = (string) de.Key;
-
- if (vi.Assigned){
- Report.Warning (
- 219, vi.Location, "The variable '" + name +
- "' is assigned but its value is never used");
- } else {
- if (!(name.Equals(lateBindingArgs)||name.Equals(lateBindingArgNames)||name.Equals(lateBindingCopyBack)))
- Report.Warning (
- 168, vi.Location, "The variable '" +
- name +"' is declared but never used");
- }
- }
- }
-
- if (children != null)
- foreach (Block b in children)
- b.UsageWarning ();
- }
-
- bool has_ret = false;
-
- public override bool Resolve (EmitContext ec)
- {
- Block prev_block = ec.CurrentBlock;
- bool ok = true;
-
- ec.CurrentBlock = this;
-
- if (!variables_initialized)
- UpdateVariableInfo (ec);
-
- ec.StartFlowBranching (this);
-
- Report.Debug (1, "RESOLVE BLOCK", StartLocation, ec.CurrentBranching);
-
- ArrayList new_statements = new ArrayList ();
- bool unreachable = false, warning_shown = false;
-
- foreach (Statement s in statements){
-
- if (unreachable && !(s is LabeledStatement)) {
- if (!warning_shown && !(s is EmptyStatement)) {
- warning_shown = true;
- Warning_DeadCodeFound (s.loc);
- }
- continue;
- }
-
- if (s.Resolve (ec) == false) {
- ok = false;
- continue;
- }
-
- if (s is LabeledStatement)
- unreachable = false;
- else
- unreachable = ! ec.CurrentBranching.IsReachable ();
-
- new_statements.Add (s);
- }
-
- statements = new_statements;
-
- Report.Debug (1, "RESOLVE BLOCK DONE", StartLocation, ec.CurrentBranching);
-
- FlowReturns returns = ec.EndFlowBranching ();
- ec.CurrentBlock = prev_block;
-
- // If we're a non-static 'struct' constructor which doesn't have an
- // initializer, then we must initialize all of the struct's fields.
- if ((this_variable != null) && (returns != FlowReturns.EXCEPTION) &&
- !this_variable.IsAssigned (ec, loc))
- ok = false;
-
- if ((labels != null) && (RootContext.WarningLevel >= 2)) {
- foreach (LabeledStatement label in labels.Values)
- if (!label.HasBeenReferenced)
- Report.Warning (164, label.Location,
- "This label has not been referenced");
- }
-
- if ((returns == FlowReturns.ALWAYS) ||
- (returns == FlowReturns.EXCEPTION) ||
- (returns == FlowReturns.UNREACHABLE))
- has_ret = true;
-
- return ok;
- }
-
- protected override bool DoEmit (EmitContext ec)
- {
- Block prev_block = ec.CurrentBlock;
-
- ec.CurrentBlock = this;
-
- ec.Mark (StartLocation);
- foreach (Statement s in statements)
- s.Emit (ec);
-
- ec.Mark (EndLocation);
-
- ec.CurrentBlock = prev_block;
- return has_ret;
- }
-
- public override string ToString ()
- {
- return String.Format ("{0} ({1}:{2})", GetType (),ID, StartLocation);
- }
-
- }
public class StatementSequence : Expression {
Block stmtBlock;
projects / mono.git / commitdiff