private static void FindLvtEntry(LocalVar lv, ClassFile.Method method, int instructionIndex)
{
ClassFile.Method.LocalVariableTableEntry[] lvt = method.LocalVariableTableAttribute;
if (lvt != null)
{
int pc = method.Instructions[instructionIndex].PC;
int nextPC = method.Instructions[instructionIndex + 1].PC;
bool isStore = IsStoreLocal(method.Instructions[instructionIndex].NormalizedOpCode);
foreach (ClassFile.Method.LocalVariableTableEntry e in lvt)
{
// TODO validate the contents of the LVT entry
if (e.index == lv.local &&
(e.start_pc <= pc || (e.start_pc == nextPC && isStore)) &&
e.start_pc + e.length > pc)
{
lv.name = e.name;
lv.start_pc = e.start_pc;
lv.end_pc = e.start_pc + e.length;
break;
}
}
}
}
internal LocalVarInfo(CodeInfo ma, ClassFile classFile, ClassFile.Method method, UntangledExceptionTable exceptions, MethodWrapper mw, ClassLoaderWrapper classLoader)
{
Dictionary <int, string>[] localStoreReaders = FindLocalVariables(ma, mw, classFile, method);
// now that we've done the code flow analysis, we can do a liveness analysis on the local variables
ClassFile.Method.Instruction[] instructions = method.Instructions;
Dictionary <long, LocalVar> localByStoreSite = new Dictionary <long, LocalVar>();
List <LocalVar> locals = new List <LocalVar>();
for (int i = 0; i < localStoreReaders.Length; i++)
{
if (localStoreReaders[i] != null)
{
VisitLocalLoads(ma, method, locals, localByStoreSite, localStoreReaders[i], i, classLoader.EmitDebugInfo);
}
}
Dictionary <LocalVar, LocalVar> forwarders = new Dictionary <LocalVar, LocalVar>();
if (classLoader.EmitDebugInfo)
{
InstructionFlags[] flags = MethodAnalyzer.ComputePartialReachability(ma, method.Instructions, exceptions, 0, false);
// if we're emitting debug info, we need to keep dead stores as well...
for (int i = 0; i < instructions.Length; i++)
{
if ((flags[i] & InstructionFlags.Reachable) != 0 &&
IsStoreLocal(instructions[i].NormalizedOpCode))
{
if (!localByStoreSite.ContainsKey(MakeKey(i, instructions[i].NormalizedArg1)))
{
LocalVar v = new LocalVar();
v.local = instructions[i].NormalizedArg1;
v.type = ma.GetStackTypeWrapper(i, 0);
FindLvtEntry(v, method, i);
locals.Add(v);
localByStoreSite.Add(MakeKey(i, v.local), v);
}
}
}
// to make the debugging experience better, we have to trust the
// LocalVariableTable (unless it's clearly bogus) and merge locals
// together that are the same according to the LVT
for (int i = 0; i < locals.Count - 1; i++)
{
for (int j = i + 1; j < locals.Count; j++)
{
LocalVar v1 = (LocalVar)locals[i];
LocalVar v2 = (LocalVar)locals[j];
if (v1.name != null && v1.name == v2.name && v1.start_pc == v2.start_pc && v1.end_pc == v2.end_pc)
{
// we can only merge if the resulting type is valid (this protects against incorrect
// LVT data, but is also needed for constructors, where the uninitialized this is a different
// type from the initialized this)
TypeWrapper tw = InstructionState.FindCommonBaseType(v1.type, v2.type);
if (tw != VerifierTypeWrapper.Invalid)
{
v1.isArg |= v2.isArg;
v1.type = tw;
forwarders.Add(v2, v1);
locals.RemoveAt(j);
j--;
}
}
}
}
}
else
{
for (int i = 0; i < locals.Count - 1; i++)
{
for (int j = i + 1; j < locals.Count; j++)
{
LocalVar v1 = (LocalVar)locals[i];
LocalVar v2 = (LocalVar)locals[j];
// if the two locals are the same, we merge them, this is a small
// optimization, it should *not* be required for correctness.
if (v1.local == v2.local && v1.type == v2.type)
{
v1.isArg |= v2.isArg;
forwarders.Add(v2, v1);
locals.RemoveAt(j);
j--;
}
}
}
}
invokespecialLocalVars = new LocalVar[instructions.Length][];
localVars = new LocalVar[instructions.Length];
for (int i = 0; i < localVars.Length; i++)
{
LocalVar v = null;
if (localStoreReaders[i] != null)
{
Debug.Assert(IsLoadLocal(instructions[i].NormalizedOpCode));
// lame way to look up the local variable for a load
// (by indirecting through a corresponding store)
foreach (int store in localStoreReaders[i].Keys)
{
v = localByStoreSite[MakeKey(store, instructions[i].NormalizedArg1)];
break;
}
}
else
{
if (instructions[i].NormalizedOpCode == NormalizedByteCode.__invokespecial)
{
invokespecialLocalVars[i] = new LocalVar[method.MaxLocals];
for (int j = 0; j < invokespecialLocalVars[i].Length; j++)
{
localByStoreSite.TryGetValue(MakeKey(i, j), out invokespecialLocalVars[i][j]);
}
}
else
{
localByStoreSite.TryGetValue(MakeKey(i, instructions[i].NormalizedArg1), out v);
}
}
if (v != null)
{
LocalVar fwd;
if (forwarders.TryGetValue(v, out fwd))
{
v = fwd;
}
localVars[i] = v;
}
}
this.allLocalVars = locals.ToArray();
}
private static void VisitLocalLoads(CodeInfo codeInfo, ClassFile.Method method, List <LocalVar> locals, Dictionary <long, LocalVar> localByStoreSite, Dictionary <int, string> storeSites, int instructionIndex, bool debug)
{
Debug.Assert(IsLoadLocal(method.Instructions[instructionIndex].NormalizedOpCode));
LocalVar local = null;
TypeWrapper type = VerifierTypeWrapper.Null;
int localIndex = method.Instructions[instructionIndex].NormalizedArg1;
bool isArg = false;
foreach (int store in storeSites.Keys)
{
if (store == -1)
{
// it's a method argument, it has no initial store, but the type is simply the parameter type
type = InstructionState.FindCommonBaseType(type, codeInfo.GetLocalTypeWrapper(0, localIndex));
isArg = true;
}
else
{
if (method.Instructions[store].NormalizedOpCode == NormalizedByteCode.__invokespecial)
{
type = InstructionState.FindCommonBaseType(type, codeInfo.GetLocalTypeWrapper(store + 1, localIndex));
}
else if (method.Instructions[store].NormalizedOpCode == NormalizedByteCode.__static_error)
{
// it's an __invokespecial that turned into a __static_error
// (since a __static_error doesn't continue, we don't need to set type)
}
else
{
Debug.Assert(IsStoreLocal(method.Instructions[store].NormalizedOpCode));
type = InstructionState.FindCommonBaseType(type, codeInfo.GetStackTypeWrapper(store, 0));
}
}
// we can't have an invalid type, because that would have failed verification earlier
Debug.Assert(type != VerifierTypeWrapper.Invalid);
LocalVar l;
if (localByStoreSite.TryGetValue(MakeKey(store, localIndex), out l))
{
if (local == null)
{
local = l;
}
else if (local != l)
{
// If we've already defined a LocalVar and we find another one, then we merge them
// together.
// This happens for the following code fragment:
//
// int i = -1;
// try { i = 0; for(; ; ) System.out.println(i); } catch(Exception x) {}
// try { i = 0; for(; ; ) System.out.println(i); } catch(Exception x) {}
// System.out.println(i);
//
local = MergeLocals(locals, localByStoreSite, local, l);
}
}
}
if (local == null)
{
local = new LocalVar();
local.local = localIndex;
if (VerifierTypeWrapper.IsThis(type))
{
local.type = ((VerifierTypeWrapper)type).UnderlyingType;
}
else
{
local.type = type;
}
local.isArg = isArg;
if (debug)
{
FindLvtEntry(local, method, instructionIndex);
}
locals.Add(local);
}
else
{
local.isArg |= isArg;
local.type = InstructionState.FindCommonBaseType(local.type, type);
Debug.Assert(local.type != VerifierTypeWrapper.Invalid);
}
foreach (int store in storeSites.Keys)
{
LocalVar v;
if (!localByStoreSite.TryGetValue(MakeKey(store, localIndex), out v))
{
localByStoreSite[MakeKey(store, localIndex)] = local;
}
else if (v != local)
{
local = MergeLocals(locals, localByStoreSite, local, v);
}
}
}
private static Dictionary <int, string>[] FindLocalVariablesImpl(CodeInfo codeInfo, ClassFile classFile, ClassFile.Method method, FindLocalVarState[] state)
{
ClassFile.Method.Instruction[] instructions = method.Instructions;
ExceptionTableEntry[] exceptions = method.ExceptionTable;
int maxLocals = method.MaxLocals;
Dictionary <int, string>[] localStoreReaders = new Dictionary <int, string> [instructions.Length];
bool done = false;
while (!done)
{
done = true;
for (int i = 0; i < instructions.Length; i++)
{
if (state[i].changed)
{
done = false;
state[i].changed = false;
FindLocalVarState curr = state[i].Copy();
for (int j = 0; j < exceptions.Length; j++)
{
if (exceptions[j].startIndex <= i && i < exceptions[j].endIndex)
{
state[exceptions[j].handlerIndex].Merge(curr);
}
}
if (IsLoadLocal(instructions[i].NormalizedOpCode) &&
(instructions[i].NormalizedOpCode != NormalizedByteCode.__aload || !VerifierTypeWrapper.IsFaultBlockException(codeInfo.GetRawStackTypeWrapper(i + 1, 0))))
{
if (localStoreReaders[i] == null)
{
localStoreReaders[i] = new Dictionary <int, string>();
}
for (int j = 0; j < curr.sites[instructions[i].NormalizedArg1].Count; j++)
{
localStoreReaders[i][curr.sites[instructions[i].NormalizedArg1][j]] = "";
}
}
if (IsStoreLocal(instructions[i].NormalizedOpCode) &&
(instructions[i].NormalizedOpCode != NormalizedByteCode.__astore || !VerifierTypeWrapper.IsFaultBlockException(codeInfo.GetRawStackTypeWrapper(i, 0))))
{
curr.Store(i, instructions[i].NormalizedArg1);
// if this is a store at the end of an exception block,
// we need to propagate the new state to the exception handler
for (int j = 0; j < exceptions.Length; j++)
{
if (exceptions[j].endIndex == i + 1)
{
state[exceptions[j].handlerIndex].Merge(curr);
}
}
}
if (instructions[i].NormalizedOpCode == NormalizedByteCode.__invokespecial)
{
ClassFile.ConstantPoolItemMI cpi = classFile.GetMethodref(instructions[i].Arg1);
if (ReferenceEquals(cpi.Name, StringConstants.INIT))
{
TypeWrapper type = codeInfo.GetRawStackTypeWrapper(i, cpi.GetArgTypes().Length);
// after we've invoked the constructor, the uninitialized references
// are now initialized
if (type == VerifierTypeWrapper.UninitializedThis ||
VerifierTypeWrapper.IsNew(type))
{
for (int j = 0; j < maxLocals; j++)
{
if (codeInfo.GetLocalTypeWrapper(i, j) == type)
{
curr.Store(i, j);
}
}
}
}
}
else if (instructions[i].NormalizedOpCode == NormalizedByteCode.__goto_finally)
{
int handler = instructions[i].HandlerIndex;
// Normally a store at the end of a try block doesn't affect the handler block,
// but in the case of a finally handler it does, so we need to make sure that
// we merge here in case the try block ended with a store.
state[handler].Merge(curr);
// Now we recursively analyse the handler and afterwards merge the endfault locations back to us
FindLocalVarState[] handlerState = new FindLocalVarState[instructions.Length];
handlerState[handler].Merge(curr);
curr = new FindLocalVarState();
FindLocalVariablesImpl(codeInfo, classFile, method, handlerState);
// Merge back to the target of our __goto_finally
for (int j = 0; j < handlerState.Length; j++)
{
if (instructions[j].NormalizedOpCode == NormalizedByteCode.__athrow &&
codeInfo.HasState(j) &&
VerifierTypeWrapper.IsFaultBlockException(codeInfo.GetRawStackTypeWrapper(j, 0)) &&
((VerifierTypeWrapper)codeInfo.GetRawStackTypeWrapper(j, 0)).Index == handler)
{
curr.Merge(handlerState[j]);
}
}
}
switch (ByteCodeMetaData.GetFlowControl(instructions[i].NormalizedOpCode))
{
case ByteCodeFlowControl.Switch:
{
for (int j = 0; j < instructions[i].SwitchEntryCount; j++)
{
state[instructions[i].GetSwitchTargetIndex(j)].Merge(curr);
}
state[instructions[i].DefaultTarget].Merge(curr);
break;
}
case ByteCodeFlowControl.Branch:
state[instructions[i].TargetIndex].Merge(curr);
break;
case ByteCodeFlowControl.CondBranch:
state[instructions[i].TargetIndex].Merge(curr);
state[i + 1].Merge(curr);
break;
case ByteCodeFlowControl.Return:
case ByteCodeFlowControl.Throw:
break;
case ByteCodeFlowControl.Next:
state[i + 1].Merge(curr);
break;
default:
throw new InvalidOperationException();
}
}
}
}
return(localStoreReaders);
}
private static Dictionary <int, string>[] FindLocalVariables(CodeInfo codeInfo, MethodWrapper mw, ClassFile classFile, ClassFile.Method method)
{
FindLocalVarState[] state = new FindLocalVarState[method.Instructions.Length];
state[0].changed = true;
state[0].sites = new FindLocalVarStoreSite[method.MaxLocals];
TypeWrapper[] parameters = mw.GetParameters();
int argpos = 0;
if (!mw.IsStatic)
{
state[0].sites[argpos++].Add(-1);
}
for (int i = 0; i < parameters.Length; i++)
{
state[0].sites[argpos++].Add(-1);
if (parameters[i].IsWidePrimitive)
{
argpos++;
}
}
return(FindLocalVariablesImpl(codeInfo, classFile, method, state));
}
