internal void CheckRemoveJumpOrigin(BasicBlock block)
{
if (CecilHelper.IsBranch(block.BranchType))
{
var target = GetBlock((Instruction)block.LastInstruction.Operand);
target.RemoveJumpOrigin(block.LastInstruction);
}
}
void CheckAddJumpOrigin(BasicBlock block)
{
if (CecilHelper.IsBranch(block.BranchType))
{
// We are adding a new branch instruction.
var target = _bb_by_instruction [(Instruction)block.LastInstruction.Operand];
target.AddJumpOrigin(new JumpOrigin(target, block, block.LastInstruction));
}
}
/*
* The block @block contains a linker conditional that resolves into the
* boolean constant @condition. There are @stackDepth extra values on the
* stack and the block ends with a branch instruction.
*
* If @condition is true, then we replace the branch with a direct jump.
*
* If @condition is false, then we remove the branch.
*
* In either case, we need to make sure to pop the extra @stackDepth values
* off the stack.
*
*/
public void ReplaceWithBranch(ref BasicBlock block, int stackDepth, bool condition)
{
if (!CecilHelper.IsBranch(block.BranchType))
{
throw new OptimizerAssertionException($"{nameof (ReplaceWithBranch)} used on non-branch block.");
}
Instruction branch = null;
if (condition)
{
branch = Instruction.Create(OpCodes.Br, (Instruction)block.LastInstruction.Operand);
}
ReplaceWithInstruction(ref block, stackDepth, branch);
}
public bool RemoveDeadBlocks()
{
Scanner.LogDebug(2, $"REMOVE DEAD BLOCKS: {Method.Name}");
Scanner.DumpBlocks(2);
var foundDeadBlocks = false;
for (int i = 0; i < BlockList.Count; i++)
{
var block = BlockList [i];
if (!block.IsDead)
{
continue;
}
Scanner.LogDebug(2, $" FOUND DEAD BLOCK: {block}");
if (CecilHelper.IsBranch(block.BranchType))
{
var target = BlockList.GetBlock((Instruction)block.LastInstruction.Operand);
target.RemoveJumpOrigin(block.LastInstruction);
}
if (block.ExceptionHandlers.Count > 0)
{
CheckRemoveExceptionBlock(ref i);
}
foundDeadBlocks = true;
}
Scanner.LogDebug(2, $"REMOVE DEAD BLOCKS #1: {Method.Name} {foundDeadBlocks}");
if (!foundDeadBlocks)
{
return(false);
}
var removedDeadBlocks = false;
for (int i = 0; i < BlockList.Count; i++)
{
var block = BlockList [i];
if (!block.IsDead)
{
continue;
}
Scanner.LogDebug(2, $" DELETING DEAD BLOCK: {block}");
BlockList.DeleteBlock(ref block);
removedDeadBlocks = true;
i--;
}
if (removedDeadBlocks)
{
BlockList.ComputeOffsets();
Scanner.LogDebug(2, $"REMOVE DEAD BLOCKS DONE: {Method.Name} {foundDeadBlocks}");
Scanner.DumpBlocks(2);
Scanner.Context.Options.OptimizerReport?.RemovedDeadBlocks(Method);
}
return(removedDeadBlocks);
}