public static Block[] DecodeFunction(MemoryManager memory, ulong address, ExecutionMode mode, bool highCq)
{
List <Block> blocks = new List <Block>();
Queue <Block> workQueue = new Queue <Block>();
Dictionary <ulong, Block> visited = new Dictionary <ulong, Block>();
int opsCount = 0;
int instructionLimit = highCq ? MaxInstsPerFunction : MaxInstsPerFunctionLowCq;
Block GetBlock(ulong blkAddress)
{
if (!visited.TryGetValue(blkAddress, out Block block))
{
if (opsCount > instructionLimit || !memory.IsMapped((long)blkAddress))
{
return(null);
}
block = new Block(blkAddress);
workQueue.Enqueue(block);
visited.Add(blkAddress, block);
}
return(block);
}
GetBlock(address);
while (workQueue.TryDequeue(out Block currBlock))
{
// Check if the current block is inside another block.
if (BinarySearch(blocks, currBlock.Address, out int nBlkIndex))
{
Block nBlock = blocks[nBlkIndex];
if (nBlock.Address == currBlock.Address)
{
throw new InvalidOperationException("Found duplicate block address on the list.");
}
nBlock.Split(currBlock);
blocks.Insert(nBlkIndex + 1, currBlock);
continue;
}
// If we have a block after the current one, set the limit address.
ulong limitAddress = ulong.MaxValue;
if (nBlkIndex != blocks.Count)
{
Block nBlock = blocks[nBlkIndex];
int nextIndex = nBlkIndex + 1;
if (nBlock.Address < currBlock.Address && nextIndex < blocks.Count)
{
limitAddress = blocks[nextIndex].Address;
}
else if (nBlock.Address > currBlock.Address)
{
limitAddress = blocks[nBlkIndex].Address;
}
}
FillBlock(memory, mode, currBlock, limitAddress);
opsCount += currBlock.OpCodes.Count;
if (currBlock.OpCodes.Count != 0)
{
// Set child blocks. "Branch" is the block the branch instruction
// points to (when taken), "Next" is the block at the next address,
// executed when the branch is not taken. For Unconditional Branches
// (except BL/BLR that are sub calls) or end of executable, Next is null.
OpCode lastOp = currBlock.GetLastOp();
bool isCall = IsCall(lastOp);
if (lastOp is IOpCodeBImm op && !isCall)
{
currBlock.Branch = GetBlock((ulong)op.Immediate);
}
if (!IsUnconditionalBranch(lastOp) || isCall)
{
currBlock.Next = GetBlock(currBlock.EndAddress);
}
}
// Insert the new block on the list (sorted by address).
if (blocks.Count != 0)
{
Block nBlock = blocks[nBlkIndex];
blocks.Insert(nBlkIndex + (nBlock.Address < currBlock.Address ? 1 : 0), currBlock);
}
else
{
blocks.Add(currBlock);
}
}
TailCallRemover.RunPass(address, blocks);
return(blocks.ToArray());
}
// ブロック単位のデコード を繰り返して複数のブロックを返す
//
// Cq = Code quality
public static Block[] Decode(IMemoryManager memory, ulong address, ExecutionMode mode, bool highCq, bool singleBlock)
{
// デコード処理したブロックが入っている これを返す
List <Block> blocks = new List <Block>();
// デコード処理をまっているブロックを入れておくキュー
Queue <Block> workQueue = new Queue <Block>();
Dictionary <ulong, Block> visited = new Dictionary <ulong, Block>();
Debug.Assert(MaxInstsPerFunctionLowCq <= MaxInstsPerFunction);
int opsCount = 0;
int instructionLimit = highCq ? MaxInstsPerFunction : MaxInstsPerFunctionLowCq;
// blkAddressを先頭とするBlock構造体を返す
// すでにBlock構造体を構築しているならそれを、そうでないなら新しく作ってworkQueueにpushしたあと返す
Block GetBlock(ulong blkAddress)
{
if (!visited.TryGetValue(blkAddress, out Block block))
{
block = new Block(blkAddress);
if ((singleBlock && visited.Count >= 1) || opsCount > instructionLimit || !memory.IsMapped(blkAddress))
{
block.Exit = true;
block.EndAddress = blkAddress;
}
workQueue.Enqueue(block);
visited.Add(blkAddress, block);
}
return(block);
}
GetBlock(address);
// キューに入ったブロックを順に処理していく
while (workQueue.TryDequeue(out Block currBlock))
{
// 処理対象のブロックがとあるブロックの内側に含まれている
// blocks[nBlkIndex].Address <= currBlock.Address < blocks[nBlkIndex].EndAddress
// currBlock.EndAddress <= blocks[nBlkIndex].EndAddress は成り立っているのか？
if (BinarySearch(blocks, currBlock.Address, out int nBlkIndex))
{
Block nBlock = blocks[nBlkIndex];
if (nBlock.Address == currBlock.Address)
{
throw new InvalidOperationException("Found duplicate block address on the list.");
}
currBlock.Exit = false; // ブロックの終端ではない
// nBlock を分割して間にcurrBlockを差し込む
nBlock.Split(currBlock);
blocks.Insert(nBlkIndex + 1, currBlock);
continue;
}
// NOTE: nBlkIndex = 新しいブロックが入るべきblocksのインデックス
// Exit=false つまり現在のブロックの後にブロックがある場合は、リミットアドレスを設定する
if (!currBlock.Exit)
{
ulong limitAddress = ulong.MaxValue;
if (nBlkIndex != blocks.Count) // 念の為処理対象のブロックがblocksの最後のブロックでないか確認
{
Block nBlock = blocks[nBlkIndex];
int nextIndex = nBlkIndex + 1;
if (nBlock.Address < currBlock.Address && nextIndex < blocks.Count)
{
// nBlock <- currBlock <- blocks[nextIndex] の場合は blocks[nextIndex] まで
limitAddress = blocks[nextIndex].Address;
}
else if (nBlock.Address > currBlock.Address)
{
// 新しいブロック -> nBlock の場合は nBlockまで
limitAddress = blocks[nBlkIndex].Address;
}
}
FillBlock(memory, mode, currBlock, limitAddress);
opsCount += currBlock.OpCodes.Count;
if (currBlock.OpCodes.Count != 0)
{
// 分岐命令だった場合に子ブロックを設定する
// "Branch "は、分岐命令が指すブロック、"Next"は、分岐しなかった場合に実行される次のアドレスのブロックです
// 無条件分岐（関数コールであるBL/BLRを除く）や実行ファイルの終了の場合、Nextはnullです。
OpCode lastOp = currBlock.GetLastOp();
bool isCall = IsCall(lastOp);
if (lastOp is IOpCodeBImm op && !isCall)
{
currBlock.Branch = GetBlock((ulong)op.Immediate);
}
if (!IsUnconditionalBranch(lastOp) || isCall)
{
currBlock.Next = GetBlock(currBlock.EndAddress);
}
}
}
// Insert the new block on the list (sorted by address).
if (blocks.Count != 0)
{
Block nBlock = blocks[nBlkIndex];
blocks.Insert(nBlkIndex + (nBlock.Address < currBlock.Address ? 1 : 0), currBlock);
}
else
{
blocks.Add(currBlock);
}
}
if (blocks.Count == 1 && blocks[0].OpCodes.Count == 0)
{
Debug.Assert(blocks[0].Exit);
Debug.Assert(blocks[0].Address == blocks[0].EndAddress);
throw new InvalidOperationException($"Decoded a single empty exit block. Entry point = 0x{address:X}.");
}
if (!singleBlock)
{
return(TailCallRemover.RunPass(address, blocks));
}
else
{
return(blocks.ToArray());
}
}
