/// <summary>
/// Ensures that the variable is of the given type(s) in the positive branch or not of this type in the negative
/// branch. If the current branch is unfeasible, assigns an appropriate boolean to the
/// <see cref="BoundExpression.ConstantValue"/> of <paramref name="checkExpr"/>.
/// </summary>
/// <param name="varRef">The reference to the variable whose types to check.</param>
/// <param name="targetType">The target type of the variable.</param>
/// <param name="branch">The branch to check - <see cref="ConditionBranch.ToTrue"/> is understood as the positive
/// branch if <paramref name="isPositiveCheck"/> is true.</param>
/// <param name="flowState">The flow state of the branch.</param>
/// <param name="skipPositiveIfAnyType">Whether to skip a mask with <see cref="TypeRefMask.IsAnyType"/> in the
/// positive branch (in the negative branch, it is always skipped).</param>
/// <param name="checkExpr">The expression to have its <see cref="BoundExpression.ConstantValue"/> potentially
/// updated.</param>
/// <param name="isPositiveCheck">Whether the expression returns true when the type check succeeds. For example,
/// in the case of != it would be false.</param>
public static void HandleTypeCheckingExpression(
BoundVariableRef varRef,
TypeRefMask targetType,
ConditionBranch branch,
FlowState flowState,
bool skipPositiveIfAnyType = false,
BoundExpression checkExpr = null,
bool isPositiveCheck = true)
{
HandleTypeCheckingExpression(varRef, (var) => targetType, branch, flowState, skipPositiveIfAnyType, checkExpr, isPositiveCheck);
}
/// <summary>
/// Sets the initial routine return type.
/// </summary>
/// <param name="ctx"></param>
/// <param name="initialState"></param>
/// <param name="phpdoc"></param>
static void InitReturn(FlowContext /*!*/ ctx, FlowState /*!*/ initialState, PHPDocBlock phpdoc)
{
Debug.Assert(ctx.ReturnVarIndex >= 0);
if (phpdoc != null)
{
var returnTag = phpdoc.Returns;
if (returnTag != null && returnTag.TypeNamesArray.Length != 0)
{
initialState.SetVar(ctx.ReturnVarIndex, PHPDoc.GetTypeMask(ctx.TypeRefContext, returnTag.TypeNamesArray));
}
}
}
/// <summary>
/// Initializes <c>$this</c> variable, its type and initialized state.
/// </summary>
private static void InitThisVar(FlowContext /*!*/ ctx, FlowState /*!*/ initialState, int varIndex)
{
var thisVarType = ctx.TypeRefContext.GetThisTypeMask();
if (thisVarType.IsUninitialized)
{
thisVarType = TypeRefMask.AnyType;
}
//
initialState.SetVarUsed(varIndex);
initialState.SetVar(varIndex, thisVarType);
}
/// <summary>
/// Creates new type context, flow context and flow state for the routine.
/// </summary>
public static FlowState CreateInitialState(SourceRoutineSymbol /*!*/ routine, FlowContext flowCtx = null)
{
Contract.ThrowIfNull(routine);
// get or create typeCtx
var typeCtx = routine.TypeRefContext;
if (flowCtx == null)
{
// create FlowContext
flowCtx = new FlowContext(typeCtx, routine);
}
// create FlowState
var state = new FlowState(flowCtx);
// handle input parameters type
foreach (var p in routine.SourceParameters)
{
var local = state.GetLocalHandle(new VariableName(p.Name));
var ptype = p.GetResultType(typeCtx);
if (p.IsNotNull)
{
// remove 'null' type from the mask,
// it cannot be null
ptype = typeCtx.WithoutNull(ptype);
}
else if (p.Type.IsReferenceType) // a reference type that can be null
{
ptype |= typeCtx.GetNullTypeMask();
}
state.SetLocalType(local, ptype);
if (p.Syntax.PassedByRef && !p.Syntax.IsVariadic)
{
state.MarkLocalByRef(local);
}
}
// $this
if (routine.GetPhpThisVariablePlace() != null)
{
InitThisVar(flowCtx, state);
}
//
return(state);
}
/// <summary>
/// Ensures that the variable is of the given type(s) in the positive branch or not of this type in the negative
/// branch. If the current branch is unfeasible, assigns an appropriate boolean to the
/// <see cref="BoundExpression.ConstantValue"/> of <paramref name="checkExpr"/>.
/// </summary>
/// <param name="varRef">The reference to the variable whose types to check.</param>
/// <param name="targetTypeCallback">The callback that receives the current type mask of the variable and returns
/// the target one.</param>
/// <param name="branch">The branch to check - <see cref="ConditionBranch.ToTrue"/> is understood as the positive
/// branch if <paramref name="isPositiveCheck"/> is true.</param>
/// <param name="flowState">The flow state of the branch.</param>
/// <param name="skipPositiveIfAnyType">Whether to skip a mask with <see cref="TypeRefMask.IsAnyType"/> in the
/// positive branch (in the negative branch, it is always skipped).</param>
/// <param name="checkExpr">The expression to have its <see cref="BoundExpression.ConstantValue"/> potentially
/// updated.</param>
/// <param name="isPositiveCheck">Whether the expression returns true when the type check succeeds. For example,
/// in the case of != it would be false.</param>
public static void HandleTypeCheckingExpression(
BoundVariableRef varRef,
Func <TypeRefMask, TypeRefMask> targetTypeCallback,
ConditionBranch branch,
FlowState flowState,
bool skipPositiveIfAnyType = false,
BoundExpression checkExpr = null,
bool isPositiveCheck = true)
{
if (!TryGetVariableHandle(varRef.Variable, flowState, out VariableHandle handle))
{
return;
}
var currentType = flowState.GetLocalType(handle);
var targetType = targetTypeCallback(currentType);
// Model negative type checks (such as $x != null) by inverting branches for the core checking function
var branchHlp = isPositiveCheck ? branch : branch.NegativeBranch();
bool isFeasible = HandleTypeChecking(currentType, targetType, branchHlp, flowState, handle, skipPositiveIfAnyType);
// If the constant value was not meant to be updated, skip its computation
if (checkExpr == null)
{
return;
}
if (!currentType.IsRef)
{
// If the true branch proves to be unfeasible, the function always returns false and vice versa
var resultConstVal = isFeasible ? default(Optional <object>) : new Optional <object>(!branch.TargetValue().Value);
// Each branch can clean only the constant value it produced during its analysis (in order not to lose result
// of the other branch): true branch can produce false value and vice versa
if (!resultConstVal.EqualsOptional(checkExpr.ConstantValue) &&
(resultConstVal.HasValue ||
checkExpr.ConstantValue.Value is false && branch == ConditionBranch.ToTrue ||
checkExpr.ConstantValue.Value is true && branch == ConditionBranch.ToFalse))
{
checkExpr.ConstantValue = resultConstVal;
}
}
else
{
// We cannot reason about the result of the check if the variable can be modified by reference
checkExpr.ConstantValue = default(Optional <object>);
}
}
/// <summary>
/// Initializes <c>$this</c> variable, its type and initialized state.
/// </summary>
private static void InitThisVar(FlowContext /*!*/ ctx, FlowState /*!*/ initialState)
{
var thisVarType = ctx.TypeRefContext.GetThisTypeMask();
if (thisVarType.IsUninitialized)
{
thisVarType = TypeRefMask.AnyType;
}
//
var thisHandle = ctx.GetVarIndex(VariableName.ThisVariableName);
initialState.SetLocalType(thisHandle, thisVarType); // set $this type
initialState.VisitLocal(thisHandle); // mark as visited (used) to not report as unused
}
public override void VisitCFGConditionalEdge(ConditionalEdge x)
{
// build state for TrueBlock and FalseBlock properly, take minimal evaluation into account
var state = _state;
// true branch
_state = state.Clone();
VisitCondition(x.Condition, ConditionBranch.ToTrue);
TraverseToBlock(x, _state, x.TrueTarget);
// false branch
_state = state.Clone();
VisitCondition(x.Condition, ConditionBranch.ToFalse);
TraverseToBlock(x, _state, x.FalseTarget);
}
/// <summary>
/// Initializes <c>$this</c> variable, its type and initialized state.
/// </summary>
private static void InitThisVar(FlowContext /*!*/ ctx, FlowState /*!*/ initialState)
{
var thisVarType = ctx.TypeRefContext.GetThisTypeMask();
if (thisVarType.IsUninitialized)
{
thisVarType = TypeRefMask.AnyType;
}
//
var thisIdx = ctx.GetVarIndex(VariableName.ThisVariableName);
initialState.SetVarUsed(thisIdx);
initialState.SetVar(thisIdx, thisVarType);
}
private static bool TryGetVariableHandle(BoundVariable boundvar, FlowState state, out VariableHandle varHandle)
{
if (boundvar.Name != null) // direct variable name
{
if (boundvar.VariableKind == VariableKind.LocalVariable || boundvar.VariableKind == VariableKind.Parameter)
{
varHandle = state.GetLocalHandle(boundvar.Name);
return(true);
}
}
//
varHandle = default(VariableHandle);
return(false);
}
private static bool TryGetVariableHandle(IVariableReference boundvar, FlowState state, out VariableHandle varHandle)
{
if (boundvar is LocalVariableReference local && local.BoundName.IsDirect) // direct variable name
{
if (local.VariableKind == VariableKind.LocalVariable ||
local.VariableKind == VariableKind.Parameter ||
local.VariableKind == VariableKind.LocalTemporalVariable)
{
varHandle = state.GetLocalHandle(local.BoundName.NameValue);
return(true);
}
}
//
varHandle = default(VariableHandle);
return(false);
}
public override void VisitCFGForeachMoveNextEdge(ForeachMoveNextEdge x)
{
var state = _state;
// get type information from Enumeree to determine types value variable
var elementType = HandleTraversableUse(x.EnumereeEdge.Enumeree);
if (elementType.IsVoid)
{
elementType = TypeRefMask.AnyType;
}
// Body branch
_state = state.Clone();
// set key variable and value variable at current state
var valueVar = x.ValueVariable;
if (valueVar is BoundListEx)
{
throw new NotImplementedException();
//VisitListEx(valueVar.List, elementType);
}
else
{
valueVar.Access = valueVar.Access.WithWrite(valueVar.Access.IsWriteRef ? elementType.WithRefFlag : elementType);
Accept(valueVar);
//
var keyVar = x.KeyVariable;
if (keyVar != null)
{
keyVar.Access = keyVar.Access.WithWrite(TypeRefMask.AnyType);
Accept(keyVar);
}
}
TraverseToBlock(x, _state, x.BodyBlock);
// End branch
_state = state.Clone();
TraverseToBlock(x, _state, x.NextBlock);
}
/// <summary>
/// Creates new type context, flow context and flow state for the routine.
/// </summary>
public static FlowState CreateInitialState(SourceRoutineSymbol /*!*/ routine, FlowContext flowCtx = null)
{
Contract.ThrowIfNull(routine);
// get or create typeCtx
var typeCtx = routine.TypeRefContext;
// create or reuse FlowContext
flowCtx ??= new FlowContext(typeCtx, routine);
// pre-allocate locals map // https://github.com/peachpiecompiler/peachpie/issues/1002
foreach (var variable in routine.LocalsTable.Variables)
{
if (variable is Semantics.LocalVariableReference local && local.VariableKind == VariableKind.LocalVariable)
{
flowCtx.GetVarIndex(variable.BoundName.NameValue);
}
}
// create FlowState
var state = new FlowState(flowCtx);
// populate input parameters type
foreach (var p in routine.SourceParameters)
{
var local = state.GetLocalHandle(new VariableName(p.Name));
var ptype = p.GetResultType(typeCtx);
state.SetLocalType(local, ptype);
}
// $this
if (routine.GetPhpThisVariablePlace() != null)
{
InitThisVar(flowCtx, state);
}
//
return(state);
}
/// <summary>
/// Creates new type context, flow context and flow state for the routine.
/// </summary>
public static FlowState CreateInitialState(SourceRoutineSymbol /*!*/ routine)
{
Contract.ThrowIfNull(routine);
// create typeCtx
var typeCtx = routine.TypeRefContext;
// create FlowContext
var flowCtx = new FlowContext(typeCtx, routine);
// create FlowState
var state = new FlowState(flowCtx);
// handle input parameters type
var parameters = routine.SourceParameters;
foreach (var p in parameters)
{
var local = state.GetLocalHandle(new VariableName(p.Name));
state.SetLocalType(local, p.GetResultType(typeCtx));
if (p.Syntax.PassedByRef && !p.Syntax.IsVariadic)
{
state.MarkLocalByRef(local);
}
}
// $this
if (routine.GetPhpThisVariablePlace() != null)
{
InitThisVar(flowCtx, state);
}
//
return(state);
}
private static bool HandleTypeChecking(
TypeRefMask currentType,
TypeRefMask targetType,
ConditionBranch branch,
FlowState flowState,
VariableHandle handle,
bool skipTrueIfAnyType)
{
// Information whether this path can ever be taken
bool isFeasible = true;
if (branch == ConditionBranch.ToTrue)
{
// In the true branch the IsAnyType case can be optionally skipped
if (skipTrueIfAnyType && currentType.IsAnyType)
{
return(isFeasible);
}
// Intersect the possible types with those checked by the function, always keeping the IsRef flag.
// IncludesSubclasses is kept only if it is specified in targetType.
TypeRefMask resultType = (currentType & (targetType | TypeRefMask.IsRefMask));
if (resultType.IsVoid)
{
// Clearing the type out in this branch means the variable will never be of that type.
// In order to prevent errors in analysis and code generation, set the type to the one specified.
resultType = targetType | (currentType & TypeRefMask.IsRefMask);
isFeasible = false;
}
flowState.SetLocalType(handle, resultType);
}
else
{
Debug.Assert(branch == ConditionBranch.ToFalse);
// In the false branch we cannot handle the IsAnyType case
if (currentType.IsAnyType)
{
return(isFeasible);
}
// Remove the types and flags excluded by the fact that the function returned false
TypeRefMask resultType = currentType & (~targetType);
if (resultType.IsVoid)
{
// Clearing the type out in this branch means the variable will always be of that type
// In order to prevent errors in analysis and code generation, do not alter the type in this case.
isFeasible = false;
}
else
{
flowState.SetLocalType(handle, resultType);
}
}
return(isFeasible);
}
/// <summary>
/// Creates new type context, flow context and flow state for the routine.
/// </summary>
public static FlowState CreateInitialState(SourceRoutineSymbol routine)
{
Contract.ThrowIfNull(routine);
var containingType = routine.ContainingType as SourceNamedTypeSymbol;
// collect locals
var locals = LocalsBinder.BindLocals(routine);
var returnIdx = locals.IndexOf(x => x.VariableKind == VariableKind.ReturnVariable);
// create typeCtx
var typeCtx = routine.TypeRefContext;
// create FlowContext
var flowCtx = new FlowContext(typeCtx, locals, returnIdx);
// create FlowState
var state = new FlowState(flowCtx, routine);
// handle parameters passed by reference
var parameters = routine.Parameters.OfType <SourceParameterSymbol>().ToImmutableArray();
foreach (var p in parameters)
{
if (p.Syntax.PassedByRef)
{
state.SetVarRef(p.Name);
}
}
// mark $this as initialized
// mark global variables as ByRef, used
// mark function parameters as used, initialized, typed
// construct initial state for variables
int paramIdx = 0;
for (int i = 0; i < locals.Length; i++)
{
switch (locals[i].VariableKind)
{
case VariableKind.GlobalVariable:
state.SetVarRef(i); // => used, byref, initialized
break;
case VariableKind.Parameter:
//state.SetVarUsed(i);
var paramtag = PHPDoc.GetParamTag(routine.PHPDocBlock, paramIdx, locals[i].Name);
state.SetVar(i, GetParamType(typeCtx, paramtag, parameters[paramIdx].Syntax, default(CallInfo), paramIdx));
paramIdx++;
break;
//case VariableKind.UseParameter:
// state.SetVar(i, TypeRefMask.AnyType);
// break;
case VariableKind.ThisParameter:
InitThisVar(flowCtx, state, i);
break;
case VariableKind.StaticVariable:
state.SetVarInitialized(i);
break;
case VariableKind.ReturnVariable:
InitReturn(flowCtx, state, routine.PHPDocBlock);
break;
}
}
//
return(state);
}
