public ProgramStepGraph BuildGraphFromMethod(Method method)
{
if (method == null)
{
throw new ArgumentNullException("method");
}
// create graph
this.graph = new ProgramStepGraph(false);
this.instructionVertices = new Hashtable();
// first add all instructions
foreach (ProgramStep i in method.DataFlow)
{
// avoid certain instructions
if (i.Operation.Flow == ControlFlow.Meta ||
i.Operation.Flow == ControlFlow.Meta)
{
continue;
}
// add vertex
ProgramStepVertex iv = graph.AddVertex();
iv.Instruction = i;
this.instructionVertices.Add((uint)i.Offset, iv);
}
// iterating over the instructions
search(null, method.DataFlow.GetEnumerator());
// iterating of the the try/catch handler
searchExceptions(method.RetrieveEHClauses());
return(this.graph);
}
private ProgramStepVertex vertexFromOffset(uint offset)
{
ProgramStepVertex iv = (ProgramStepVertex)this.instructionVertices[offset];
if (iv == null)
{
throw new InvalidOperationException("Could not find vertex at offset " + offset.ToString());
}
return(iv);
}
private void searchExceptions(ICollection exceptions)
{
if (exceptions == null)
{
return;
}
// handle all catch
foreach (EHClause handler in exceptions)
{
if (handler.TryOffset == handler.HandlerOffset)
{
continue;
}
ProgramStepVertex tv = vertexFromOffset(handler.TryOffset);
if (handler.Type == EHClauseTypes.EHNone)
{
ProgramStepVertex cv = vertexFromOffset(handler.HandlerOffset);
graph.AddEdge(tv, cv);
}
if (handler.Type == EHClauseTypes.EHFilter)
{
ProgramStepVertex cv = vertexFromOffset(handler.ClassTokenOrFilterOffset);
graph.AddEdge(tv, cv);
}
if (handler.Type == EHClauseTypes.EHFinally)
{
ProgramStepVertex fv = vertexFromOffset(handler.HandlerOffset);
graph.AddEdge(tv, fv);
foreach (EHClause catchHandler in exceptions)
{
if (catchHandler.TryOffset == catchHandler.HandlerOffset)
{
continue;
}
if (handler.TryOffset != catchHandler.TryOffset)
{
continue;
}
if (handler.HandlerOffset == catchHandler.HandlerOffset)
{
continue;
}
ProgramStepVertex cv = vertexFromOffset(catchHandler.HandlerOffset);
graph.AddEdge(cv, fv);
}
}
}
}
private void search(
ProgramStepVertex parentVertex,
IEnumerator instructions)
{
ProgramStepVertex jv = null;
ProgramStepVertex cv = parentVertex;
while (instructions.MoveNext())
{
// add vertex to graph
ProgramStep i = (ProgramStep)instructions.Current;
ControlFlow f = i.Operation.Flow;
// avoid certain instructions
if (f == ControlFlow.Phi ||
f == ControlFlow.Meta)
{
continue;
}
ProgramStepVertex iv = vertexFromOffset((uint)i.Offset);
if (cv != null)
{
graph.AddEdge(cv, iv);
}
// find how to handle the rest
switch (f)
{
case ControlFlow.Next:
cv = iv;
break;
case ControlFlow.Call:
cv = iv;
break;
case ControlFlow.Return:
cv = null;
break;
case ControlFlow.Throw:
cv = null;
break;
case ControlFlow.ConditionalBranch:
if (i.Operation.StringName == "switch")
{
foreach (int target in (int[])i.Operand)
{
jv = vertexFromOffset((uint)target);
graph.AddEdge(iv, jv);
search(iv, instructions);
}
cv = iv;
}
else
{
sbyte targetOffset = (System.SByte)iv.Instruction.Operand;
jv = vertexFromOffset((uint)targetOffset + 3);
graph.AddEdge(iv, jv);
cv = iv;
}
break;
case ControlFlow.Branch:
if (i.Operation.StringName.StartsWith("brtrue") ||
i.Operation.StringName.StartsWith("brfalse")
)
{
// add jump to offset
sbyte targetOffset = (System.SByte)iv.Instruction.Operand;
jv = vertexFromOffset((uint)targetOffset + 3);
if (jv == null)
{
throw new VertexNotFoundException("Could not find vertex");
}
graph.AddEdge(iv, jv);
cv = null;
break;
}
break;
case ControlFlow.Break:
// add jump to offset
jv = vertexFromOffset((uint)iv.Instruction.Offset);
graph.AddEdge(iv, jv);
cv = null;
break;
}
}
}
private void search(
ProgramStepVertex parentVertex,
IEnumerator instructions)
{
ProgramStepVertex jv = null;
ProgramStepVertex cv = parentVertex;
while(instructions.MoveNext())
{
// add vertex to graph
ProgramStep i = (ProgramStep)instructions.Current;
ControlFlow f = i.Operation.Flow;
// avoid certain instructions
if (f == ControlFlow.Phi
|| f == ControlFlow.Meta)
continue;
ProgramStepVertex iv = vertexFromOffset((uint)i.Offset);
if (cv!=null)
{
graph.AddEdge(cv, iv);
}
// find how to handle the rest
switch(f)
{
case ControlFlow.Next:
cv = iv;
break;
case ControlFlow.Call:
cv=iv;
break;
case ControlFlow.Return:
cv = null;
break;
case ControlFlow.Throw:
cv = null;
break;
case ControlFlow.ConditionalBranch:
if (i.Operation.StringName == "switch")
{
foreach(int target in (int[])i.Operand)
{
jv = vertexFromOffset((uint)target);
graph.AddEdge(iv,jv);
search(iv,instructions);
}
cv=iv;
}
else
{
sbyte targetOffset = (System.SByte)iv.Instruction.Operand;
jv = vertexFromOffset((uint)targetOffset+3);
graph.AddEdge(iv,jv);
cv = iv;
}
break;
case ControlFlow.Branch:
if (i.Operation.StringName.StartsWith("brtrue")
|| i.Operation.StringName.StartsWith("brfalse")
)
{
// add jump to offset
sbyte targetOffset = (System.SByte)iv.Instruction.Operand;
jv = vertexFromOffset((uint)targetOffset+3);
if (jv==null)
throw new VertexNotFoundException("Could not find vertex");
graph.AddEdge(iv,jv);
cv=null;
break;
}
break;
case ControlFlow.Break:
// add jump to offset
jv = vertexFromOffset((uint)iv.Instruction.Offset);
graph.AddEdge(iv,jv);
cv = null;
break;
}
}
}