/// <summary>
/// Splits the block.
/// </summary>
/// <param name="ctx">The context.</param>
/// <param name="addJump">if set to <c>true</c> [add jump].</param>
/// <returns></returns>
protected Context SplitContext(Context ctx, bool addJump)
{
Context current = ctx.Clone();
int label = basicBlocks.Count + 0x10000000;
BasicBlock nextBlock = CreateBlock(label);
foreach (BasicBlock block in current.BasicBlock.NextBlocks)
{
nextBlock.NextBlocks.Add(block);
}
current.BasicBlock.NextBlocks.Clear();
if (addJump)
{
current.BasicBlock.NextBlocks.Add(nextBlock);
nextBlock.PreviousBlocks.Add(ctx.BasicBlock);
}
if (current.IsLastInstruction)
{
current.AppendInstruction(null);
current.Ignore = true;
nextBlock.Index = current.Index;
current.SliceBefore();
}
else
{
nextBlock.Index = current.Next.Index;
current.SliceAfter();
}
if (addJump)
{
current.AppendInstruction(IR.Instruction.JmpInstruction, nextBlock);
}
return(CreateContext(nextBlock));
}
/// <summary>
/// Finds all targets.
/// </summary>
/// <param name="index">The index.</param>
private void SplitIntoBlocks(int index)
{
Dictionary <int, int> targets = new Dictionary <int, int>();
targets.Add(index, -1);
// Find out all targets labels
for (Context ctx = new Context(InstructionSet, index); !ctx.EndOfInstruction; ctx.GotoNext())
{
switch (ctx.Instruction.FlowControl)
{
case FlowControl.Next: continue;
case FlowControl.Call: continue;
case FlowControl.Break:
goto case FlowControl.Branch;
case FlowControl.Return:
continue;
case FlowControl.Throw:
goto case FlowControl.Branch;
case FlowControl.Branch:
// Unconditional branch
Debug.Assert(ctx.Branch.Targets.Length == 1);
if (!targets.ContainsKey(ctx.Branch.Targets[0]))
{
targets.Add(ctx.Branch.Targets[0], -1);
}
continue;
case FlowControl.Switch: goto case FlowControl.ConditionalBranch;
case FlowControl.ConditionalBranch:
// Conditional branch with multiple targets
foreach (int target in ctx.Branch.Targets)
{
if (!targets.ContainsKey(target))
{
targets.Add(target, -1);
}
}
int next = ctx.Next.Label;
if (!targets.ContainsKey(next))
{
targets.Add(next, -1);
}
continue;
default:
Debug.Assert(false);
break;
}
}
bool slice = false;
for (Context ctx = new Context(InstructionSet, index); !ctx.EndOfInstruction; ctx.GotoNext())
{
FlowControl flow;
if (targets.ContainsKey(ctx.Label))
{
CreateBlock(ctx.Label, ctx.Index);
if (!ctx.IsFirstInstruction)
{
Context prev = ctx.Previous;
flow = prev.Instruction.FlowControl;
if (flow == FlowControl.Next || flow == FlowControl.Call || flow == FlowControl.ConditionalBranch || flow == FlowControl.Switch)
{
prev.AppendInstruction(IR.Instruction.JmpInstruction);
prev.SetBranch(ctx.Label);
prev.SliceAfter();
}
}
targets.Remove(ctx.Label);
}
if (slice)
{
ctx.SliceBefore();
}
flow = ctx.Instruction.FlowControl;
slice = (flow == FlowControl.Return || flow == FlowControl.Branch || flow == FlowControl.ConditionalBranch || flow == FlowControl.Break || flow == FlowControl.Throw);
}
Debug.Assert(targets.Count <= 1);
if (FindBlock(0) == null)
{
CreateBlock(0, index);
}
}