Symbol * Symbol::GetFuncScopeVarSym() const
{
if (!this->GetIsBlockVar())
{
return nullptr;
}
FuncInfo * parentFuncInfo = this->GetScope()->GetFunc();
if (parentFuncInfo->GetIsStrictMode())
{
return nullptr;
}
Symbol *fncScopeSym = parentFuncInfo->GetBodyScope()->FindLocalSymbol(this->GetName());
if (fncScopeSym == nullptr && parentFuncInfo->GetParamScope() != nullptr)
{
// We couldn't find the sym in the body scope, try finding it in the parameter scope.
fncScopeSym = parentFuncInfo->GetParamScope()->FindLocalSymbol(this->GetName());
}
Assert(fncScopeSym);
// Parser should have added a fake var decl node for block scoped functions in non-strict mode
// IsBlockVar() indicates a user let declared variable at function scope which
// shadows the function's var binding, thus only emit the var binding init if
// we do not have a block var symbol.
if (!fncScopeSym || fncScopeSym->GetIsBlockVar())
{
return nullptr;
}
return fncScopeSym;
}
Symbol * Symbol::GetFuncScopeVarSym() const
{
if (!this->GetIsBlockVar())
{
return nullptr;
}
FuncInfo * parentFuncInfo = this->GetScope()->GetFunc();
if (parentFuncInfo->GetIsStrictMode())
{
return nullptr;
}
Symbol *fncScopeSym = parentFuncInfo->GetBodyScope()->FindLocalSymbol(this->GetName());
if (fncScopeSym == nullptr && parentFuncInfo->GetParamScope() != nullptr)
{
// We couldn't find the sym in the body scope, try finding it in the parameter scope.
Scope* paramScope = parentFuncInfo->GetParamScope();
fncScopeSym = paramScope->FindLocalSymbol(this->GetName());
if (fncScopeSym == nullptr)
{
FuncInfo* parentParentFuncInfo = paramScope->GetEnclosingScope()->GetFunc();
if (parentParentFuncInfo->root->sxFnc.IsAsync())
{
// In the case of async functions the func-scope var sym might have
// come from the parent function parameter scope due to the syntax
// desugaring implementation of async functions.
fncScopeSym = parentParentFuncInfo->GetBodyScope()->FindLocalSymbol(this->GetName());
if (fncScopeSym == nullptr)
{
fncScopeSym = parentParentFuncInfo->GetParamScope()->FindLocalSymbol(this->GetName());
}
}
}
}
Assert(fncScopeSym);
// Parser should have added a fake var decl node for block scoped functions in non-strict mode
// IsBlockVar() indicates a user let declared variable at function scope which
// shadows the function's var binding, thus only emit the var binding init if
// we do not have a block var symbol.
if (!fncScopeSym || fncScopeSym->GetIsBlockVar())
{
return nullptr;
}
return fncScopeSym;
}
void Symbol::SetHasNonLocalReference(bool b, ByteCodeGenerator *byteCodeGenerator)
{
this->hasNonLocalReference = b;
// The symbol's home function will tell us which child function we're currently processing.
// This is the one that captures the symbol, from the declaring function's perspective.
// So based on that information, note either that, (a.) the symbol is committed to the heap from its
// inception, (b.) the symbol must be committed when the capturing function is instantiated.
FuncInfo *funcHome = this->scope->GetFunc();
FuncInfo *funcChild = funcHome->GetCurrentChildFunction();
// If this is not a local property, or not all its references can be tracked, or
// it's not scoped to the function, or we're in debug mode, disable the delayed capture optimization.
if (funcHome->IsGlobalFunction() ||
funcHome->GetCallsEval() ||
funcHome->GetChildCallsEval() ||
funcChild == nullptr ||
this->GetScope() != funcHome->GetBodyScope() ||
byteCodeGenerator->IsInDebugMode() ||
PHASE_OFF(Js::DelayCapturePhase, funcHome->byteCodeFunction))
{
this->SetIsCommittedToSlot();
}
if (this->isCommittedToSlot)
{
return;
}
AnalysisAssert(funcChild);
ParseNode *pnodeChild = funcChild->root;
Assert(pnodeChild && pnodeChild->nop == knopFncDecl);
if (pnodeChild->sxFnc.IsDeclaration())
{
// The capturing function is a declaration but may still be limited to an inner scope.
Scope *scopeChild = funcHome->GetCurrentChildScope();
if (scopeChild == this->scope || scopeChild->GetScopeType() == ScopeType_FunctionBody)
{
// The symbol is captured on entry to the scope in which it's declared.
// (Check the scope type separately so that we get the special parameter list and
// named function expression cases as well.)
this->SetIsCommittedToSlot();
return;
}
}
// There is a chance we can limit the region in which the symbol lives on the heap.
// Note which function captures the symbol.
funcChild->AddCapturedSym(this);
}
