public static Block[] DecodeBasicBlock(MemoryManager memory, ulong address, ExecutionMode mode)
{
Block block = new Block(address);
FillBlock(memory, mode, block, ulong.MaxValue);
OpCode64 lastOp = block.GetLastOp();
if (IsBranch(lastOp) && !IsCall(lastOp) && lastOp is IOpCodeBImm op)
{
//It's possible that the branch on this block lands on the middle of the block.
//This is more common on tight loops. In this case, we can improve the codegen
//a bit by changing the CFG and either making the branch point to the same block
//(which indicates that the block is a loop that jumps back to the start), and the
//other possible case is a jump somewhere on the middle of the block, which is
//also a loop, but in this case we need to split the block in half.
if ((ulong)op.Imm == address)
{
block.Branch = block;
}
else if ((ulong)op.Imm > address &&
(ulong)op.Imm < block.EndAddress)
{
Block rightBlock = new Block((ulong)op.Imm);
block.Split(rightBlock);
return(new Block[] { block, rightBlock });
}
}
return(new Block[] { block });
}
public static OpCode64 DecodeOpCode(CpuThreadState state, MemoryManager memory, long position)
{
int opCode = memory.ReadInt32(position);
Inst inst;
if (state.ExecutionMode == ExecutionMode.AArch64)
{
inst = OpCodeTable.GetInstA64(opCode);
}
else
{
//TODO: Thumb support.
inst = OpCodeTable.GetInstA32(opCode);
}
OpCode64 decodedOpCode = new OpCode64(Inst.Undefined, position, opCode);
if (inst.Type != null)
{
decodedOpCode = MakeOpCode(inst.Type, inst, position, opCode);
}
return(decodedOpCode);
}
public static OpCode64 DecodeOpCode(MemoryManager memory, long position, ExecutionMode mode)
{
int opCode = memory.ReadInt32(position);
Inst inst;
if (mode == ExecutionMode.Aarch64)
{
inst = OpCodeTable.GetInstA64(opCode);
}
else
{
if (mode == ExecutionMode.Aarch32Arm)
{
inst = OpCodeTable.GetInstA32(opCode);
}
else /* if (mode == ExecutionMode.Aarch32Thumb) */
{
inst = OpCodeTable.GetInstT32(opCode);
}
}
OpCode64 decodedOpCode = new OpCode64(Inst.Undefined, position, opCode);
if (inst.Type != null)
{
decodedOpCode = MakeOpCode(inst.Type, inst, position, opCode);
}
return(decodedOpCode);
}
private static int BinarySearch(List <OpCode64> opCodes, ulong address)
{
int left = 0;
int middle = 0;
int right = opCodes.Count - 1;
while (left <= right)
{
int size = right - left;
middle = left + (size >> 1);
OpCode64 opCode = opCodes[middle];
if (address == (ulong)opCode.Position)
{
break;
}
if (address < (ulong)opCode.Position)
{
right = middle - 1;
}
else
{
left = middle + 1;
}
}
return(middle);
}
private static bool IsAarch32Branch(OpCode64 opCode)
{
//Note: On ARM32, most ALU operations can write to R15 (PC),
//so we must consider such operations as a branch in potential aswell.
if (opCode is IOpCode32Alu opAlu && opAlu.Rd == RegisterAlias.Aarch32Pc)
{
return(true);
}
//Same thing for memory operations. We have the cases where PC is a target
//register (Rt == 15 or (mask & (1 << 15)) != 0), and cases where there is
//a write back to PC (wback == true && Rn == 15), however the later may
//be "undefined" depending on the CPU, so compilers should not produce that.
if (opCode is IOpCode32Mem || opCode is IOpCode32MemMult)
{
int rt, rn;
bool wBack, isLoad;
if (opCode is IOpCode32Mem opMem)
{
rt = opMem.Rt;
rn = opMem.Rn;
wBack = opMem.WBack;
isLoad = opMem.IsLoad;
//For the dual load, we also need to take into account the
//case were Rt2 == 15 (PC).
if (rt == 14 && opMem.Emitter == InstEmit32.Ldrd)
{
rt = RegisterAlias.Aarch32Pc;
}
}
else if (opCode is IOpCode32MemMult opMemMult)
{
const int pcMask = 1 << RegisterAlias.Aarch32Pc;
rt = (opMemMult.RegisterMask & pcMask) != 0 ? RegisterAlias.Aarch32Pc : 0;
rn = opMemMult.Rn;
wBack = opMemMult.PostOffset != 0;
isLoad = opMemMult.IsLoad;
}
else
{
throw new NotImplementedException($"The type \"{opCode.GetType().Name}\" is not implemented on the decoder.");
}
if ((rt == RegisterAlias.Aarch32Pc && isLoad) ||
(rn == RegisterAlias.Aarch32Pc && wBack))
{
return(true);
}
}
//Explicit branch instructions.
return(opCode is IOpCode32BImm ||
opCode is IOpCode32BReg);
}
private static bool IsAarch32UnconditionalBranch(OpCode64 opCode)
{
if (!(opCode is OpCode32 op))
{
return(false);
}
//Note: On ARM32, most instructions have conditional execution,
//so there's no "Always" (unconditional) branch like on ARM64.
//We need to check if the condition is "Always" instead.
return(IsAarch32Branch(op) && op.Cond >= Condition.Al);
}
public static Block DecodeBasicBlock(MemoryManager memory, long start, ExecutionMode mode)
{
Block block = new Block(start);
FillBlock(memory, mode, block);
OpCode64 lastOp = block.GetLastOp();
if (IsBranch(lastOp) && !IsCall(lastOp) && lastOp is IOpCodeBImm op)
{
//It's possible that the branch on this block lands on the middle of the block.
//This is more common on tight loops. In this case, we can improve the codegen
//a bit by changing the CFG and either making the branch point to the same block
//(which indicates that the block is a loop that jumps back to the start), and the
//other possible case is a jump somewhere on the middle of the block, which is
//also a loop, but in this case we need to split the block in half.
if (op.Imm == start)
{
block.Branch = block;
}
else if ((ulong)op.Imm > (ulong)start &&
(ulong)op.Imm < (ulong)block.EndPosition)
{
Block botBlock = new Block(op.Imm);
int botBlockIndex = 0;
long currPosition = start;
while ((ulong)currPosition < (ulong)op.Imm)
{
currPosition += block.OpCodes[botBlockIndex++].OpCodeSizeInBytes;
}
botBlock.OpCodes.AddRange(block.OpCodes);
botBlock.OpCodes.RemoveRange(0, botBlockIndex);
block.OpCodes.RemoveRange(botBlockIndex, block.OpCodes.Count - botBlockIndex);
botBlock.EndPosition = block.EndPosition;
block.EndPosition = op.Imm;
botBlock.Branch = botBlock;
block.Next = botBlock;
}
}
return(block);
}
public static (Block[] Graph, Block Root) DecodeSubroutine(
TranslatorCache cache,
CpuThreadState state,
MemoryManager memory,
long start)
{
Dictionary <long, Block> visited = new Dictionary <long, Block>();
Dictionary <long, Block> visitedEnd = new Dictionary <long, Block>();
Queue <Block> blocks = new Queue <Block>();
Block Enqueue(long position)
{
if (!visited.TryGetValue(position, out Block output))
{
output = new Block(position);
blocks.Enqueue(output);
visited.Add(position, output);
}
return(output);
}
Block root = Enqueue(start);
while (blocks.Count > 0)
{
Block current = blocks.Dequeue();
FillBlock(state, memory, current);
//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.
if (current.OpCodes.Count > 0)
{
bool hasCachedSub = false;
OpCode64 lastOp = current.GetLastOp();
if (lastOp is OpCodeBImm64 op)
{
if (op.Emitter == InstEmit.Bl)
{
hasCachedSub = cache.HasSubroutine(op.Imm);
}
else
{
current.Branch = Enqueue(op.Imm);
}
}
if (!((lastOp is OpCodeBImmAl64) ||
(lastOp is OpCodeBReg64)) || hasCachedSub)
{
current.Next = Enqueue(current.EndPosition);
}
}
//If we have on the graph two blocks with the same end position,
//then we need to split the bigger block and have two small blocks,
//the end position of the bigger "Current" block should then be == to
//the position of the "Smaller" block.
while (visitedEnd.TryGetValue(current.EndPosition, out Block smaller))
{
if (current.Position > smaller.Position)
{
Block temp = smaller;
smaller = current;
current = temp;
}
current.EndPosition = smaller.Position;
current.Next = smaller;
current.Branch = null;
current.OpCodes.RemoveRange(
current.OpCodes.Count - smaller.OpCodes.Count,
smaller.OpCodes.Count);
visitedEnd[smaller.EndPosition] = smaller;
}
visitedEnd.Add(current.EndPosition, current);
}
//Make and sort Graph blocks array by position.
Block[] graph = new Block[visited.Count];
while (visited.Count > 0)
{
ulong firstPos = ulong.MaxValue;
foreach (Block block in visited.Values)
{
if (firstPos > (ulong)block.Position)
{
firstPos = (ulong)block.Position;
}
}
Block current = visited[(long)firstPos];
do
{
graph[graph.Length - visited.Count] = current;
visited.Remove(current.Position);
current = current.Next;
}while (current != null);
}
return(graph, root);
}
private static bool IsException(OpCode64 opCode)
{
return(opCode.Emitter == InstEmit.Brk ||
opCode.Emitter == InstEmit.Svc ||
opCode.Emitter == InstEmit.Und);
}
private static bool IsBranch(OpCode64 opCode)
{
return(opCode is OpCodeBImm64 ||
opCode is OpCodeBReg64);
}
public static Block DecodeSubroutine(
TranslatorCache cache,
MemoryManager memory,
long start,
ExecutionMode mode)
{
Dictionary <long, Block> visited = new Dictionary <long, Block>();
Dictionary <long, Block> visitedEnd = new Dictionary <long, Block>();
Queue <Block> blocks = new Queue <Block>();
Block Enqueue(long position)
{
if (!visited.TryGetValue(position, out Block output))
{
output = new Block(position);
blocks.Enqueue(output);
visited.Add(position, output);
}
return(output);
}
Block entry = Enqueue(start);
while (blocks.Count > 0)
{
Block current = blocks.Dequeue();
FillBlock(memory, mode, current);
//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.
if (current.OpCodes.Count > 0)
{
bool hasCachedSub = false;
OpCode64 lastOp = current.GetLastOp();
if (lastOp is IOpCodeBImm op)
{
if (op.Emitter == InstEmit.Bl)
{
hasCachedSub = cache.HasSubroutine(op.Imm);
}
else
{
current.Branch = Enqueue(op.Imm);
}
}
if (!IsUnconditionalBranch(lastOp) || hasCachedSub)
{
current.Next = Enqueue(current.EndPosition);
}
}
//If we have on the graph two blocks with the same end position,
//then we need to split the bigger block and have two small blocks,
//the end position of the bigger "Current" block should then be == to
//the position of the "Smaller" block.
while (visitedEnd.TryGetValue(current.EndPosition, out Block smaller))
{
if (current.Position > smaller.Position)
{
Block temp = smaller;
smaller = current;
current = temp;
}
current.EndPosition = smaller.Position;
current.Next = smaller;
current.Branch = null;
current.OpCodes.RemoveRange(
current.OpCodes.Count - smaller.OpCodes.Count,
smaller.OpCodes.Count);
visitedEnd[smaller.EndPosition] = smaller;
}
visitedEnd.Add(current.EndPosition, current);
}
return(entry);
}
private static bool IsUnconditionalBranch(OpCode64 opCode)
{
return(opCode is OpCodeBImmAl64 ||
opCode is OpCodeBReg64 || IsAarch32UnconditionalBranch(opCode));
}
public static Block[] DecodeSubroutine(MemoryManager memory, ulong address, ExecutionMode mode)
{
List <Block> blocks = new List <Block>();
Queue <Block> workQueue = new Queue <Block>();
Dictionary <ulong, Block> visited = new Dictionary <ulong, Block>();
Block GetBlock(ulong blkAddress)
{
if (!visited.TryGetValue(blkAddress, out Block block))
{
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);
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.
OpCode64 lastOp = currBlock.GetLastOp();
bool isCall = IsCall(lastOp);
if (lastOp is IOpCodeBImm op && !isCall)
{
currBlock.Branch = GetBlock((ulong)op.Imm);
}
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);
}
}
return(blocks.ToArray());
}
private static bool IsCall(OpCode64 opCode)
{
//TODO (CQ): ARM32 support.
return(opCode.Emitter == InstEmit.Bl ||
opCode.Emitter == InstEmit.Blr);
}