public void RewriteConditionals()
{
LogDebug(1, $"REWRITE CONDITIONALS: {Method.Name}");
DumpBlocks();
var foundConditionals = false;
foreach (var block in BlockList.Blocks.ToArray())
{
if (block.LinkerConditional == null)
{
continue;
}
RewriteLinkerConditional(block);
block.LinkerConditional = null;
foundConditionals = true;
}
if (!foundConditionals)
{
return;
}
BlockList.ComputeOffsets();
DumpBlocks();
LogDebug(1, $"DONE REWRITING CONDITIONALS: {Method.Name}");
Context.Options.OptimizerReport.MarkAsContainingConditionals(Method);
EliminateDeadBlocks();
}
void RewriteLinkerConditional(BasicBlock block)
{
LogDebug(1, $"REWRITE LINKER CONDITIONAL: {block.LinkerConditional}");
DumpBlocks();
var conditional = block.LinkerConditional;
block.LinkerConditional = null;
conditional.RewriteConditional(ref block);
BlockList.ComputeOffsets();
DumpBlocks();
LogDebug(1, $"DONE REWRITING LINKER CONDITIONAL");
}
void EliminateDeadBlocks(bool full = true)
{
if (!Context.Options.DeadCodeElimination)
{
return;
}
LogDebug(1, $"ELIMINATING DEAD BLOCKS");
bool removed;
bool first = true;
do
{
if (first)
{
first = false;
}
else
{
Scan();
}
var flow = new FlowAnalysis(this);
flow.Analyze();
removed = false;
var eliminator = new DeadCodeEliminator(this);
removed |= eliminator.RemoveDeadBlocks();
if (full)
{
removed |= eliminator.RemoveDeadJumps();
removed |= eliminator.RemoveConstantJumps();
}
removed |= eliminator.RemoveUnusedVariables();
if (removed)
{
BlockList.ComputeOffsets();
}
LogDebug(1, $"ELIMINATING DEAD BLOCKS DONE: {removed}");
} while (full && removed);
}
bool Scan()
{
LogDebug(1, $"SCAN: {Method}");
BasicBlock bb = null;
if (DebugLevel > 0)
{
Context.Debug();
}
if (!BlockList.Initialize())
{
return(false);
}
for (int i = 0; i < Method.Body.Instructions.Count; i++)
{
var instruction = Method.Body.Instructions [i];
if (BlockList.TryGetBlock(instruction, out var newBB))
{
if (bb != null && bb.BranchType != BranchType.None)
{
throw DebugHelpers.AssertFail(Method, bb, $"Found known basic block with unexpected branch type `{bb.BranchType}`");
}
LogDebug(2, $" KNOWN BB: {newBB}");
bb = newBB;
}
else if (bb == null)
{
bb = BlockList.NewBlock(instruction);
LogDebug(2, $" NEW BB: {bb}");
}
else
{
bb.AddInstruction(instruction);
}
var type = CecilHelper.GetBranchType(instruction);
LogDebug(2, $" {type}: {CecilHelper.Format (instruction)}");
if (instruction.OpCode.OperandType == OperandType.InlineMethod)
{
if (LinkerConditional.Scan(this, ref bb, ref i, instruction))
{
FoundConditionals = true;
}
continue;
}
switch (type)
{
case BranchType.None:
break;
case BranchType.Conditional:
case BranchType.False:
case BranchType.True:
case BranchType.Jump:
BlockList.AddJumpOrigin(bb, instruction, (Instruction)instruction.Operand);
bb = null;
break;
case BranchType.Exit:
case BranchType.Return:
case BranchType.EndFinally:
bb = null;
break;
case BranchType.Switch:
foreach (var label in (Instruction [])bb.LastInstruction.Operand)
{
BlockList.AddJumpOrigin(bb, instruction, label);
}
bb = null;
break;
default:
throw new OptimizerAssertionException();
}
}
BlockList.ComputeOffsets();
DumpBlocks();
if (Context.Options.AnalyzeAll || FoundConditionals || DebugLevel > 3)
{
EliminateDeadBlocks();
DumpBlocks();
return(true);
}
return(true);
}
