//
// flowanalyis.cs: The control flow analysis code
//
-// Author:
+// Authors:
// Martin Baulig (martin@ximian.com)
// Raja R Harinath (rharinath@novell.com)
+// Marek Safar (marek.safar@gmail.com)
//
// Copyright 2001, 2002, 2003 Ximian, Inc.
// Copyright 2003-2008 Novell, Inc.
public bool IsFieldAssigned (VariableInfo var, string name)
{
- if (!var.IsParameter && IsUnreachable)
+ if (/*!var.IsParameter &&*/ IsUnreachable)
return true;
- return var.IsFieldAssigned (locals, name);
+ return var.IsStructFieldAssigned (locals, name);
}
public void SetFieldAssigned (VariableInfo var, string name)
{
- if (!var.IsParameter && IsUnreachable)
+ if (/*!var.IsParameter &&*/ IsUnreachable)
return;
- var.SetFieldAssigned (locals, name);
+ var.SetStructFieldAssigned (locals, name);
}
public bool IsUnreachable {
- get { return is_unreachable; }
+ get {
+ return is_unreachable;
+ }
+ set {
+ is_unreachable = value;
+ }
}
public void ResetBarrier ()
return CurrentUsageVector.IsAssigned (vi, false);
}
- public bool IsFieldAssigned (VariableInfo vi, string field_name)
+ public bool IsStructFieldAssigned (VariableInfo vi, string field_name)
{
return CurrentUsageVector.IsAssigned (vi, false) || CurrentUsageVector.IsFieldAssigned (vi, field_name);
}
protected override UsageVector Merge ()
{
for (UsageVector origin = return_origins; origin != null; origin = origin.Next)
- Block.ParametersBlock.CheckOutParameters (origin, origin.Location);
+ Block.ParametersBlock.CheckOutParameters (origin);
UsageVector vector = base.Merge ();
- Block.ParametersBlock.CheckOutParameters (vector, Block.loc);
+ Block.ParametersBlock.CheckOutParameters (vector);
// Note: we _do_not_ merge in the return origins
return vector;
}
}
// <summary>
- // This is used by the flow analysis code to keep track of the type of local variables
- // and variables.
+ // This is used by the flow analysis code to keep track of the type of local variables.
//
// The flow code uses a BitVector to keep track of whether a variable has been assigned
// or not. This is easy for fundamental types (int, char etc.) or reference types since
// </summary>
public class TypeInfo
{
- public readonly TypeSpec Type;
-
// <summary>
// Total number of bits a variable of this type consumes in the flow vector.
// </summary>
// <summary>
// If this is a struct.
// </summary>
- public readonly bool IsStruct;
+ public readonly bool IsStruct;
// <summary>
// If this is a struct, all fields which are structs theirselves.
readonly StructInfo struct_info;
private static Dictionary<TypeSpec, TypeInfo> type_hash;
+
+ static readonly TypeInfo simple_type = new TypeInfo (1);
static TypeInfo ()
{
StructInfo.field_type_hash = new Dictionary<TypeSpec, StructInfo> ();
}
- public static TypeInfo GetTypeInfo (TypeSpec type)
+ TypeInfo (int totalLength)
{
- TypeInfo info;
- if (type_hash.TryGetValue (type, out info))
- return info;
-
- info = new TypeInfo (type);
- type_hash.Add (type, info);
- return info;
+ this.TotalLength = totalLength;
}
-
- private TypeInfo (TypeSpec type)
- {
- this.Type = type;
-
- struct_info = StructInfo.GetStructInfo (type);
- if (struct_info != null) {
- Length = struct_info.Length;
- TotalLength = struct_info.TotalLength;
- SubStructInfo = struct_info.StructFields;
- IsStruct = true;
- } else {
- Length = 0;
- TotalLength = 1;
- IsStruct = false;
- }
- }
-
+
TypeInfo (StructInfo struct_info, int offset)
{
this.struct_info = struct_info;
this.Length = struct_info.Length;
this.TotalLength = struct_info.TotalLength;
this.SubStructInfo = struct_info.StructFields;
- this.Type = struct_info.Type;
this.IsStruct = true;
}
-
+
public int GetFieldIndex (string name)
{
if (struct_info == null)
return struct_info [name];
}
- public TypeInfo GetSubStruct (string name)
+ public TypeInfo GetStructField (string name)
{
if (struct_info == null)
return null;
return struct_info.GetStructField (name);
}
+ public static TypeInfo GetTypeInfo (TypeSpec type)
+ {
+ if (!type.IsStruct)
+ return simple_type;
+
+ TypeInfo info;
+ if (type_hash.TryGetValue (type, out info))
+ return info;
+
+ var struct_info = StructInfo.GetStructInfo (type);
+ if (struct_info != null) {
+ info = new TypeInfo (struct_info, 0);
+ } else {
+ info = simple_type;
+ }
+
+ type_hash.Add (type, info);
+ return info;
+ }
+
// <summary>
// A struct's constructor must always assign all fields.
// This method checks whether it actually does so.
for (int i = 0; i < struct_info.Count; i++) {
var field = struct_info.Fields [i];
- // Fixed size buffers are not subject to definite assignment checking
- if (field is FixedFieldSpec)
- continue;
-
- if (!branching.IsFieldAssigned (vi, field.Name)) {
+ if (!branching.IsStructFieldAssigned (vi, field.Name)) {
if (field.MemberDefinition is Property.BackingField) {
ec.Report.Error (843, loc,
"An automatically implemented property `{0}' must be fully assigned before control leaves the constructor. Consider calling the default struct contructor from a constructor initializer",
public override string ToString ()
{
- return String.Format ("TypeInfo ({0}:{1}:{2}:{3})",
- Type, Offset, Length, TotalLength);
+ return String.Format ("TypeInfo ({0}:{1}:{2})",
+ Offset, Length, TotalLength);
}
- class StructInfo {
- public readonly TypeSpec Type;
- public readonly FieldSpec[] Fields;
+ class StructInfo
+ {
+ readonly List<FieldSpec> fields;
public readonly TypeInfo[] StructFields;
- public readonly int Count;
- public readonly int CountPublic;
- public readonly int CountNonPublic;
public readonly int Length;
public readonly int TotalLength;
- public readonly bool HasStructFields;
public static Dictionary<TypeSpec, StructInfo> field_type_hash;
private Dictionary<string, TypeInfo> struct_field_hash;
private Dictionary<string, int> field_hash;
- protected bool InTransit = false;
+ bool InTransit;
- // Private constructor. To save memory usage, we only need to create one instance
- // of this class per struct type.
- private StructInfo (TypeSpec type)
+ //
+ // We only need one instance per type
+ //
+ StructInfo (TypeSpec type)
{
- this.Type = type;
-
field_type_hash.Add (type, this);
- TypeContainer tc = type.MemberDefinition as TypeContainer;
-
- var public_fields = new List<FieldSpec> ();
- var non_public_fields = new List<FieldSpec> ();
-
- if (tc != null) {
- var fields = tc.Fields;
-
- if (fields != null) {
- foreach (FieldBase field in fields) {
- if ((field.ModFlags & Modifiers.STATIC) != 0)
- continue;
- if ((field.ModFlags & Modifiers.PUBLIC) != 0)
- public_fields.Add (field.Spec);
- else
- non_public_fields.Add (field.Spec);
- }
- }
- }
-
- CountPublic = public_fields.Count;
- CountNonPublic = non_public_fields.Count;
- Count = CountPublic + CountNonPublic;
-
- Fields = new FieldSpec[Count];
- public_fields.CopyTo (Fields, 0);
- non_public_fields.CopyTo (Fields, CountPublic);
+ fields = MemberCache.GetAllFieldsForDefiniteAssignment (type);
struct_field_hash = new Dictionary<string, TypeInfo> ();
- field_hash = new Dictionary<string, int> ();
+ field_hash = new Dictionary<string, int> (fields.Count);
- Length = 0;
- StructFields = new TypeInfo [Count];
- StructInfo[] sinfo = new StructInfo [Count];
+ StructFields = new TypeInfo[fields.Count];
+ StructInfo[] sinfo = new StructInfo[fields.Count];
InTransit = true;
- for (int i = 0; i < Count; i++) {
- var field = Fields [i];
+ for (int i = 0; i < fields.Count; i++) {
+ var field = fields [i];
+
+ if (field.MemberType.IsStruct)
+ sinfo [i] = GetStructInfo (field.MemberType);
- sinfo [i] = GetStructInfo (field.MemberType);
if (sinfo [i] == null)
field_hash.Add (field.Name, ++Length);
else if (sinfo [i].InTransit) {
InTransit = false;
TotalLength = Length + 1;
- for (int i = 0; i < Count; i++) {
- var field = Fields [i];
+ for (int i = 0; i < fields.Count; i++) {
+ var field = fields [i];
if (sinfo [i] == null)
continue;
field_hash.Add (field.Name, TotalLength);
- HasStructFields = true;
StructFields [i] = new TypeInfo (sinfo [i], TotalLength);
struct_field_hash.Add (field.Name, StructFields [i]);
TotalLength += sinfo [i].TotalLength;
}
}
+ public int Count {
+ get {
+ return fields.Count;
+ }
+ }
+
+ public List<FieldSpec> Fields {
+ get {
+ return fields;
+ }
+ }
+
public int this [string name] {
get {
int val;
public static StructInfo GetStructInfo (TypeSpec type)
{
- if (!type.IsStruct || type.BuiltinType > 0)
+ if (type.BuiltinType > 0)
return null;
StructInfo info;
// it has been assigned or not, but for structs, we need this information for each of its fields.
// </summary>
public class VariableInfo {
- public readonly string Name;
- public readonly TypeInfo TypeInfo;
+ readonly string Name;
+ readonly TypeInfo TypeInfo;
// <summary>
// The bit offset of this variable in the flow vector.
// </summary>
- public readonly int Offset;
+ readonly int Offset;
// <summary>
// The number of bits this variable needs in the flow vector.
// </summary>
public readonly bool IsParameter;
- public readonly LocalVariable LocalInfo;
-
- readonly VariableInfo Parent;
VariableInfo[] sub_info;
- bool is_ever_assigned;
- public bool IsEverAssigned {
- get { return is_ever_assigned; }
- }
-
- protected VariableInfo (string name, TypeSpec type, int offset)
+ VariableInfo (string name, TypeSpec type, int offset)
{
this.Name = name;
this.Offset = offset;
Initialize ();
}
- protected VariableInfo (VariableInfo parent, TypeInfo type)
+ VariableInfo (VariableInfo parent, TypeInfo type)
{
this.Name = parent.Name;
this.TypeInfo = type;
this.Offset = parent.Offset + type.Offset;
- this.Parent = parent;
this.Length = type.TotalLength;
this.IsParameter = parent.IsParameter;
- this.LocalInfo = parent.LocalInfo;
Initialize ();
}
public VariableInfo (LocalVariable local_info, int offset)
: this (local_info.Name, local_info.Type, offset)
{
- this.LocalInfo = local_info;
this.IsParameter = false;
}
public bool IsAssigned (ResolveContext ec)
{
- return !ec.DoFlowAnalysis ||
- (ec.OmitStructFlowAnalysis && TypeInfo.Type.IsStruct) ||
- ec.CurrentBranching.IsAssigned (this);
- }
-
- public bool IsAssigned (ResolveContext ec, Location loc)
- {
- if (IsAssigned (ec))
- return true;
-
- ec.Report.Error (165, loc,
- "Use of unassigned local variable `" + Name + "'");
- ec.CurrentBranching.SetAssigned (this);
- return false;
+ return !ec.DoFlowAnalysis || ec.CurrentBranching.IsAssigned (this);
}
public bool IsAssigned (MyBitVector vector)
if (vector [Offset])
return true;
- // FIXME: Fix SetFieldAssigned to set the whole range like SetAssigned below. Then, get rid of this stanza
- for (VariableInfo parent = Parent; parent != null; parent = parent.Parent) {
- if (vector [parent.Offset]) {
- // 'parent' is assigned, but someone forgot to note that all its components are assigned too
- parent.SetAssigned (vector);
- return true;
- }
- }
-
- // Return unless this is a struct.
+ // Unless this is a struct
if (!TypeInfo.IsStruct)
return false;
- // Ok, so each field must be assigned.
- for (int i = 0; i < TypeInfo.Length; i++) {
- if (!vector [Offset + i + 1])
+ //
+ // Following case cannot be handled fully by SetStructFieldAssigned
+ // because we may encounter following case
+ //
+ // struct A { B b }
+ // struct B { int value; }
+ //
+ // setting a.b.value is propagated only to B's vector and not upwards to possible parents
+ //
+ //
+ // Each field must be assigned
+ //
+ for (int i = Offset + 1; i <= TypeInfo.Length + Offset; i++) {
+ if (!vector[i])
return false;
}
// Ok, now check all fields which are structs.
for (int i = 0; i < sub_info.Length; i++) {
- VariableInfo sinfo = sub_info [i];
+ VariableInfo sinfo = sub_info[i];
if (sinfo == null)
continue;
if (!sinfo.IsAssigned (vector))
return false;
}
-
+
vector [Offset] = true;
- is_ever_assigned = true;
return true;
}
- public void SetAssigned (ResolveContext ec)
- {
- if (ec.DoFlowAnalysis)
- ec.CurrentBranching.SetAssigned (this);
- }
+ public bool IsEverAssigned { get; set; }
- public void SetAssigned (MyBitVector vector)
+ public bool IsStructFieldAssigned (ResolveContext ec, string name)
{
- if (Length == 1)
- vector [Offset] = true;
- else
- vector.SetRange (Offset, Length);
- is_ever_assigned = true;
+ return !ec.DoFlowAnalysis || ec.CurrentBranching.IsStructFieldAssigned (this, name);
}
- public bool IsFieldAssigned (ResolveContext ec, string name, Location loc)
+ public bool IsFullyInitialized (BlockContext bc, Location loc)
{
- if (!ec.DoFlowAnalysis ||
- ec.OmitStructFlowAnalysis && TypeInfo.IsStruct ||
- ec.CurrentBranching.IsFieldAssigned (this, name))
- return true;
-
- ec.Report.Error (170, loc,
- "Use of possibly unassigned field `" + name + "'");
- ec.CurrentBranching.SetFieldAssigned (this, name);
- return false;
+ return TypeInfo.IsFullyInitialized (bc, this, loc);
}
- public bool IsFieldAssigned (MyBitVector vector, string field_name)
+ public bool IsStructFieldAssigned (MyBitVector vector, string field_name)
{
int field_idx = TypeInfo.GetFieldIndex (field_name);
return vector [Offset + field_idx];
}
- public void SetFieldAssigned (ResolveContext ec, string name)
+ public void SetStructFieldAssigned (ResolveContext ec, string name)
{
if (ec.DoFlowAnalysis)
ec.CurrentBranching.SetFieldAssigned (this, name);
}
- public void SetFieldAssigned (MyBitVector vector, string field_name)
+ public void SetAssigned (ResolveContext ec)
+ {
+ if (ec.DoFlowAnalysis)
+ ec.CurrentBranching.SetAssigned (this);
+ }
+
+ public void SetAssigned (MyBitVector vector)
+ {
+ if (Length == 1)
+ vector[Offset] = true;
+ else
+ vector.SetRange (Offset, Length);
+
+ IsEverAssigned = true;
+ }
+
+ public void SetStructFieldAssigned (MyBitVector vector, string field_name)
{
+ if (vector[Offset])
+ return;
+
int field_idx = TypeInfo.GetFieldIndex (field_name);
if (field_idx == 0)
return;
- vector [Offset + field_idx] = true;
- is_ever_assigned = true;
+ var complex_field = TypeInfo.GetStructField (field_name);
+ if (complex_field != null) {
+ vector.SetRange (Offset + complex_field.Offset, complex_field.TotalLength);
+ } else {
+ vector[Offset + field_idx] = true;
+ }
+
+ IsEverAssigned = true;
+
+ //
+ // Each field must be assigned
+ //
+ for (int i = Offset + 1; i < TypeInfo.TotalLength + Offset; i++) {
+ if (!vector[i])
+ return;
+ }
+
+ //
+ // Set master struct flag to assigned when all tested struct
+ // fields have been assigned
+ //
+ vector[Offset] = true;
}
- public VariableInfo GetSubStruct (string name)
+ public VariableInfo GetStructFieldInfo (string fieldName)
{
- TypeInfo type = TypeInfo.GetSubStruct (name);
+ TypeInfo type = TypeInfo.GetStructField (fieldName);
if (type == null)
return null;
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