/// <summary>
/// Processes the data flow of a block by beginning with
/// the dataOut after the last instruction, simluates all instructions
/// until the beginning of the block is reached, and percolates any
/// *changes* to predecessor blocks to the worklist for futher processing.
/// </summary>
/// <param name="item">The block dataflow item we are about to process</param>
public void ProcessBlock(BlockFlow item)
{
bool t = trace.TraceInfo;
if (t)
{
Debug.Write(item.Block.Procedure.Name + ", ");
DumpBlock(item.Block);
}
varLive.Identifiers = new HashSet <RegisterStorage>(item.DataOut);
varLive.Grf = item.grfOut;
varLive.LiveStorages = new Dictionary <Storage, int>(item.StackVarsOut);
Debug.WriteLineIf(t, string.Format(" out: {0}", DumpRegisters(varLive.Identifiers)));
Procedure = item.Block.Procedure; // Used by statements because we need to look up registers using identifiers and the procedure frame.
StatementList stms = item.Block.Statements;
for (int i = stms.Count - 1; i >= 0; --i)
{
stmCur = stms[i];
Debug.WriteLineIf(t, stms[i].Instruction);
stmCur.Instruction.Accept(this);
Debug.WriteLineIf(t, string.Format("\tin: {0}", DumpRegisters(varLive.Identifiers)));
}
if (item.Block == item.Block.Procedure.EntryBlock)
{
PropagateToProcedureSummary(varLive, item.Block.Procedure);
}
else
{
PropagateToPredecessorBlocks(item);
}
}
/// <summary>
/// Propagates liveness information to predecessor blocks, but only
/// if there are changes to their dataOut fields.
/// </summary>
/// <param name="item"></param>
private void PropagateToPredecessorBlocks(BlockFlow item)
{
foreach (Block p in item.Block.Pred)
{
MergeBlockInfo(p);
}
}
public void EnsureEvaluationContext(BlockFlow bf)
{
this.ctx = bf.SymbolicIn.Clone();
var tes = new TrashedExpressionSimplifier(this, ctx);
this.se = new SymbolicEvaluator(tes, ctx);
}
/// <summary>
/// Merges the liveness information accumulated in <paramref name="varLive"/> into <paramref name="blockFlow"/>
/// </summary>
/// <param name="varLive">Current liveness state</param>
/// <param name="blockFlow">liveness information associated with a block</param>
/// <returns>Return true if merging the livness information changed the information in the block flow.</returns>
public virtual bool MergeBlockInfo(IdentifierLiveness varLive, BlockFlow blockFlow)
{
bool ret = false;
int oldCount = blockFlow.DataOut.Count;
blockFlow.DataOut.UnionWith(varLive.Identifiers);
if (blockFlow.DataOut.Count != oldCount)
{
ret = true;
}
if ((varLive.Grf & (~blockFlow.grfOut)) != 0)
{
blockFlow.grfOut |= varLive.Grf;
ret = true;
}
IDictionary <Storage, int> dict = blockFlow.StackVarsOut;
foreach (KeyValuePair <Storage, int> de in varLive.LiveStorages)
{
if (!dict.ContainsKey(de.Key))
{
dict.Add(de.Key, de.Value);
ret = true;
}
}
return(ret);
}
public void DumpProgram()
{
foreach (Procedure proc in program.Procedures.Values)
{
StringWriter output = new StringWriter();
ProcedureFlow pf = this.flow[proc];
TextFormatter f = new TextFormatter(output);
if (pf.Signature != null)
{
pf.Signature.Emit(proc.Name, FunctionType.EmitFlags.None, f);
}
else
{
proc.Signature.Emit(proc.Name, FunctionType.EmitFlags.None, f);
}
output.WriteLine();
pf.Emit(proc.Architecture, output);
output.WriteLine("// {0}", proc.Name);
proc.Signature.Emit(proc.Name, FunctionType.EmitFlags.None, f);
output.WriteLine();
foreach (Block block in proc.ControlGraph.Blocks)
{
if (block != null)
{
BlockFlow bf = this.flow[block];
bf.Emit(proc.Architecture, output);
output.WriteLine();
block.Write(output);
}
}
Debug.WriteLine(output.ToString());
}
}
public void MergeBlockInfo(Block block)
{
BlockFlow blockFlow = mpprocData[block];
if (state.MergeBlockInfo(varLive, blockFlow))
{
worklist.Add(blockFlow);
}
}
public void PropagateToSuccessorBlock(Block s)
{
BlockFlow succFlow = flow[s];
bool changed = MergeDataFlow(succFlow);
if (changed)
{
worklist.Add(s);
}
}
private BlockFlow CreateBlockFlow(Block block, Frame frame)
{
var bflow = new BlockFlow(
block,
prog.Architecture.CreateRegisterBitset(),
new SymbolicEvaluationContext(
prog.Architecture,
frame));
flow[block] = bflow;
return bflow;
}
public void StartProcessingBlock(Block block)
{
bf = flow[block];
EnsureEvaluationContext(bf);
if (block.Procedure.EntryBlock == block)
{
var sp = block.Procedure.Frame.EnsureRegister(program.Architecture.StackRegister);
bf.SymbolicIn.RegisterState[sp.Storage] = block.Procedure.Frame.FramePointer;
}
ctx.TrashedFlags = bf.grfTrashedIn;
}
private BlockFlow CreateBlockFlow(Block block, Frame frame)
{
var bflow = new BlockFlow(
block,
new HashSet<RegisterStorage>(),
new SymbolicEvaluationContext(
program.Architecture,
frame));
flow[block] = bflow;
return bflow;
}
/// <summary>
/// Make summary information available in LiveIn and LiveOut for each procedure.
/// </summary>
private void CompleteWork()
{
foreach (Procedure proc in program.Procedures.Values)
{
ProcedureFlow pi = mpprocData[proc];
BlockFlow bi = mpprocData[proc.ExitBlock];
pi.LiveOut = bi.DataOut;
pi.grfLiveOut = bi.grfOut;
// Remove unneeded data. Done for performance (and to give GC something to do).
pi.ByPass.Clear();
}
}
public void StartBlock(Block block)
{
this.block = block;
if (this.pdf != null)
{
BlockFlow bf = pdf[block];
var marker = new AliasDeadVariableMarker(bf.DataOut, bf.grfOut);
deadIn = marker.Compute(arch, proc.Frame);
}
else
{
// If no global analysis available, be pessimistic and assume
// all variables are live-out of every block.
deadIn = new HashSet <Identifier>();
}
}
public override bool MergeBlockInfo(IdentifierLiveness varLive, BlockFlow blockFlow)
{
bool ret = false;
if (!(~varLive.BitSet & blockFlow.DataOut).IsEmpty)
{
blockFlow.DataOut |= varLive.BitSet;
ret = true;
}
if ((~varLive.Grf & blockFlow.grfOut) != 0)
{
blockFlow.grfOut |= varLive.Grf;
ret = true;
}
return(ret);
}
public ProgramDataFlow(Program program) : this()
{
foreach (Procedure proc in program.Procedures.Values)
{
procFlow[proc] = new ProcedureFlow(proc, program.Architecture);
foreach (Block block in proc.ControlGraph.Blocks)
{
blockFlow[block] = new BlockFlow(
block,
new HashSet<RegisterStorage>(),
new SymbolicEvaluationContext(
program.Architecture,
proc.Frame));
}
}
}
public ProgramDataFlow(Program prog) : this()
{
foreach (Procedure proc in prog.Procedures.Values)
{
procFlow[proc] = new ProcedureFlow(proc, prog.Architecture);
foreach (Block block in proc.ControlGraph.Blocks)
{
blockFlow[block] = new BlockFlow(
block,
prog.Architecture.CreateRegisterBitset(),
new SymbolicEvaluationContext(
prog.Architecture,
proc.Frame));
}
}
}
public ProgramDataFlow(Program program) : this()
{
foreach (Procedure proc in program.Procedures.Values)
{
procFlow[proc] = new ProcedureFlow(proc, proc.Architecture);
foreach (Block block in proc.ControlGraph.Blocks)
{
blockFlow[block] = new BlockFlow(
block,
new HashSet <RegisterStorage>(),
new SymbolicEvaluationContext(
proc.Architecture,
proc.Frame));
}
}
}
public ProgramDataFlow(Program prog) : this()
{
foreach (Procedure proc in prog.Procedures.Values)
{
procFlow[proc] = new ProcedureFlow(proc, prog.Architecture);
foreach (Block block in proc.ControlGraph.Blocks)
{
blockFlow[block] = new BlockFlow(
block,
prog.Architecture.CreateRegisterBitset(),
new SymbolicEvaluationContext(
prog.Architecture,
proc.Frame));
}
}
}
public override bool MergeBlockInfo(IdentifierLiveness varLive, BlockFlow blockFlow)
{
bool changed = false;
int oldCount = blockFlow.DataOut.Count;
blockFlow.DataOut.UnionWith(varLive.Identifiers);
if (blockFlow.DataOut.Count != oldCount)
{
changed = true;
}
if ((~varLive.Grf & blockFlow.grfOut) != 0)
{
blockFlow.grfOut |= varLive.Grf;
changed = true;
}
return(changed);
}
public override void InitializeBlockFlow(Block block, ProgramDataFlow flow, bool isExitBlock)
{
BlockFlow bf = flow[block];
if (isExitBlock && block.Procedure.Signature.ParametersValid)
{
Identifier ret = block.Procedure.Signature.ReturnValue;
if (ret != null)
{
RegisterStorage rs = ret.Storage as RegisterStorage;
if (rs != null)
{
bf.DataOut.UnionWith(arch.GetAliases(rs));
}
}
foreach (Identifier id in block.Procedure.Signature.Parameters)
{
OutArgumentStorage os = id.Storage as OutArgumentStorage;
if (os == null)
{
continue;
}
RegisterStorage rs = os.OriginalIdentifier.Storage as RegisterStorage;
if (rs != null)
{
bf.DataOut.UnionWith(arch.GetAliases(rs));
}
}
}
else if (bf.TerminatesProcess)
{
bf.DataOut.Clear();
}
else
{
bf.DataOut.Clear();
if (isExitBlock)
{
//Add all registers except preserved registers
bf.DataOut.UnionWith(arch.GetRegisters());
bf.DataOut.ExceptWith(flow[block.Procedure].PreservedRegisters);
}
}
}
public bool MergeDataFlow(BlockFlow succFlow)
{
var ctxSucc = succFlow.SymbolicIn;
bool changed = false;
foreach (var de in ctx.RegisterState)
{
Expression oldValue;
if (!ctxSucc.RegisterState.TryGetValue(de.Key, out oldValue))
{
ctxSucc.RegisterState[de.Key] = de.Value;
changed = true;
}
else if (oldValue != Constant.Invalid && !ecomp.Equals(oldValue, de.Value))
{
ctxSucc.RegisterState[de.Key] = Constant.Invalid;
changed = true;
}
}
foreach (var de in ctx.StackState)
{
Expression oldValue;
if (!ctxSucc.StackState.TryGetValue(de.Key, out oldValue))
{
ctxSucc.StackState[de.Key] = de.Value;
changed = true;
}
else if (!ecomp.Equals(oldValue, de.Value) && oldValue != Constant.Invalid)
{
ctxSucc.StackState[de.Key] = Constant.Invalid;
changed = true;
}
}
uint grfNew = succFlow.grfTrashedIn | ctx.TrashedFlags;
if (grfNew != succFlow.grfTrashedIn)
{
succFlow.grfTrashedIn = grfNew;
changed = true;
}
return(changed);
}
public override void InitializeBlockFlow(Block block, ProgramDataFlow flow, bool isExitBlock)
{
BlockFlow bf = flow[block];
if (isExitBlock && block.Procedure.Signature.ParametersValid)
{
Identifier ret = block.Procedure.Signature.ReturnValue;
if (ret != null)
{
RegisterStorage rs = ret.Storage as RegisterStorage;
if (rs != null)
{
rs.SetAliases(bf.DataOut, true);
}
}
foreach (Identifier id in block.Procedure.Signature.Parameters)
{
OutArgumentStorage os = id.Storage as OutArgumentStorage;
if (os == null)
{
continue;
}
RegisterStorage rs = os.OriginalIdentifier.Storage as RegisterStorage;
if (rs != null)
{
rs.SetAliases(bf.DataOut, true);
}
}
}
else if (bf.TerminatesProcess)
{
bf.DataOut.SetAll(false);
}
else
{
bf.DataOut.SetAll(isExitBlock);
bf.DataOut &= ~flow[block.Procedure].PreservedRegisters;
}
}
private void Given_Contexts()
{
frame = new Frame(PrimitiveType.Pointer32);
ctx = new SymbolicEvaluationContext(arch, frame);
blockflow = new BlockFlow(null, new HashSet<RegisterStorage>(), ctx);
trf.EnsureEvaluationContext(blockflow);
}
private void Given_Contexts()
{
frame = new Frame(PrimitiveType.Pointer32);
ctx = new SymbolicEvaluationContext(arch, frame);
blockflow = new BlockFlow(null, arch.CreateRegisterBitset(), ctx);
trf.EnsureEvaluationContext(blockflow);
}
public void TrfPropagateToSuccessorBlocks()
{
Procedure proc = new Procedure("test", program.Architecture.CreateFrame());
var frame = proc.Frame;
Identifier ecx = m.Register(1);
Identifier edx = m.Register(2);
Identifier ebx = m.Register(3);
Block b = proc.AddBlock("b");
Block t = proc.AddBlock("t");
Block e = proc.AddBlock("e");
proc.ControlGraph.AddEdge(b, e);
proc.ControlGraph.AddEdge(b, t);
flow[t] = new BlockFlow(t, null, new SymbolicEvaluationContext(program.Architecture, frame));
flow[e] = new BlockFlow(e, null, new SymbolicEvaluationContext(program.Architecture, frame));
trf = CreateTrashedRegisterFinder(program);
CreateBlockFlow(b, frame);
trf.StartProcessingBlock(b);
trf.RegisterSymbolicValues[(RegisterStorage) ecx.Storage] = Constant.Invalid;
trf.RegisterSymbolicValues[(RegisterStorage) edx.Storage] = ebx;
flow[e].SymbolicIn.RegisterState[(RegisterStorage) ecx.Storage] = edx;
flow[e].SymbolicIn.RegisterState[(RegisterStorage) edx.Storage] = ebx;
flow[t].SymbolicIn.RegisterState[(RegisterStorage) ecx.Storage] = Constant.Invalid;
flow[t].SymbolicIn.RegisterState[(RegisterStorage) edx.Storage] = edx;
trf.PropagateToSuccessorBlock(e);
trf.PropagateToSuccessorBlock(t);
Assert.AreEqual(2, proc.ControlGraph.Successors(b).Count);
Assert.AreEqual("<invalid>", flow[e].SymbolicIn.RegisterState[(RegisterStorage) ecx.Storage].ToString(), "trash & r2 => trash");
Assert.AreEqual("ebx", flow[e].SymbolicIn.RegisterState[(RegisterStorage) edx.Storage].ToString(), "ebx & ebx => ebx");
Assert.AreEqual("<invalid>", flow[e].SymbolicIn.RegisterState[(RegisterStorage) ecx.Storage].ToString(), "trash & r2 => trash");
Assert.AreEqual("ebx", flow[e].SymbolicIn.RegisterState[(RegisterStorage) edx.Storage].ToString(), "ebx & ebx => ebx");
Assert.AreEqual("<invalid>", flow[t].SymbolicIn.RegisterState[(RegisterStorage) ecx.Storage].ToString(), "trash & trash => trash");
Assert.AreEqual("<invalid>", flow[t].SymbolicIn.RegisterState[(RegisterStorage) edx.Storage].ToString(), "r3 & r2 => trash");
}
