dataflow.h

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

//
// This class is used to perform data flow optimizations.
// An example usage would be:
//
// DataFlow flow(m_pCompiler);
// flow.ForwardAnalysis(callback);
//
// The "callback" object needs to implement the following member
// functions that the "flow" object will call as the data flow
// analysis progresses:
//
// class Callback
// {
// public:
// void StartMerge(BasicBlock* block);
// void Merge(BasicBlock* block, BasicBlock* pred, flowList* preds);
// bool EndMerge(BasicBlock* block);
// };
#pragma once

#include"compiler.h"
#include"jitstd.h"

classDataFlow
{
private:
DataFlow();

public:
DataFlow(Compiler* pCompiler);

template <typename TCallback>
voidForwardAnalysis(TCallback& callback);

private:
 Compiler* m_pCompiler;
};

template <typename TCallback>
voidDataFlow::ForwardAnalysis(TCallback& callback)
{
 jitstd::list<BasicBlock*> worklist(jitstd::allocator<void>(m_pCompiler->getAllocator()));

 worklist.insert(worklist.begin(), m_pCompiler->fgFirstBB);
while (!worklist.empty())
 {
 BasicBlock* block = *(worklist.begin());
 worklist.erase(worklist.begin());

 callback.StartMerge(block);
 {
 flowList* preds = m_pCompiler->BlockPredsWithEH(block);
for (flowList* pred = preds; pred; pred = pred->flNext)
 {
 callback.Merge(block, pred->flBlock, preds);
 }
 }

if (callback.EndMerge(block))
 {
for (BasicBlock* succ : block->GetAllSuccs(m_pCompiler))
 {
 worklist.insert(worklist.end(), succ);
 }
 }
 }
}