/// <summary>
/// Creates a small basic block, consisting solely of a 'call' followed by a 'return'
/// instruction.
/// </summary>
/// <remarks>
/// This is done when encountering tail calls (i.e. jumps) from one
/// procedure into another.
/// </remarks>
/// <param name="addrFrom"></param>
/// <param name="procOld"></param>
/// <param name="procNew"></param>
/// <returns></returns>
public Block CreateCallRetThunk(Address addrFrom, Procedure procOld, Procedure procNew)
{
//$BUG: ReturnAddressOnStack property needs to be properly set, the
// EvenOdd sample shows how this doesn't work currently.
var blockName = string.Format(
"{0}_thunk_{1}",
Program.NamingPolicy.BlockName(addrFrom),
procNew.Name);
var callRetThunkBlock = procOld.AddSyntheticBlock(
addrFrom,
blockName);
if (Program.User.BlockLabels.TryGetValue(blockName, out var userLabel))
{
callRetThunkBlock.UserLabel = userLabel;
}
var linFrom = addrFrom.ToLinear();
callRetThunkBlock.Statements.Add(
linFrom,
new CallInstruction(
new ProcedureConstant(Program.Platform.PointerType, procNew),
new CallSite(0, 0)));
Program.CallGraph.AddEdge(callRetThunkBlock.Statements.Last !, procNew);
callRetThunkBlock.Statements.Add(linFrom, new ReturnInstruction());
procOld.ControlGraph.AddEdge(callRetThunkBlock, procOld.ExitBlock);
SetProcedureReturnAddressBytes(procOld, procNew.Frame.ReturnAddressSize, addrFrom);
return(callRetThunkBlock);
}
