luau/Analysis/include/Luau/DataFlowGraph.h
vegorov-rbx 59ae47db43
Sync to upstream/release/555 (#768)
* Type mismatch errors now mention if unification failed in covariant or
invariant context, to explain why sometimes derived class can't be
converted to base class or why `T` can't be converted into `T?` and so
on
* Class type indexing is no longer an error in non-strict mode (still an
error in strict mode)
* Fixed cyclic type packs not being displayed in the type
* Added an error when unrelated types are compared with `==`/`~=`
* Fixed false positive errors involving sub-type tests an `never` type
* Fixed miscompilation of multiple assignment statements (Fixes
https://github.com/Roblox/luau/issues/754)
* Type inference stability improvements
2022-12-02 10:09:59 -08:00

121 lines
4.7 KiB
C++

// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
#pragma once
// Do not include LValue. It should never be used here.
#include "Luau/Ast.h"
#include "Luau/DenseHash.h"
#include "Luau/Def.h"
#include "Luau/Symbol.h"
#include <unordered_map>
namespace Luau
{
struct DataFlowGraph
{
DataFlowGraph(DataFlowGraph&&) = default;
DataFlowGraph& operator=(DataFlowGraph&&) = default;
// TODO: AstExprLocal, AstExprGlobal, and AstLocal* are guaranteed never to return nullopt.
// We leave them to return an optional as we build it out, but the end state is for them to return a non-optional DefId.
std::optional<DefId> getDef(const AstExpr* expr) const;
std::optional<DefId> getDef(const AstLocal* local) const;
/// Retrieve the Def that corresponds to the given Symbol.
///
/// We do not perform dataflow analysis on globals, so this function always
/// yields nullopt when passed a global Symbol.
std::optional<DefId> getDef(const Symbol& symbol) const;
private:
DataFlowGraph() = default;
DataFlowGraph(const DataFlowGraph&) = delete;
DataFlowGraph& operator=(const DataFlowGraph&) = delete;
DefArena arena;
DenseHashMap<const AstExpr*, const Def*> astDefs{nullptr};
DenseHashMap<const AstLocal*, const Def*> localDefs{nullptr};
friend struct DataFlowGraphBuilder;
};
struct DfgScope
{
DfgScope* parent;
DenseHashMap<Symbol, const Def*> bindings{Symbol{}};
};
struct ExpressionFlowGraph
{
std::optional<DefId> def;
};
// Currently unsound. We do not presently track the control flow of the program.
// Additionally, we do not presently track assignments.
struct DataFlowGraphBuilder
{
static DataFlowGraph build(AstStatBlock* root, NotNull<struct InternalErrorReporter> handle);
private:
DataFlowGraphBuilder() = default;
DataFlowGraphBuilder(const DataFlowGraphBuilder&) = delete;
DataFlowGraphBuilder& operator=(const DataFlowGraphBuilder&) = delete;
DataFlowGraph graph;
NotNull<DefArena> arena{&graph.arena};
struct InternalErrorReporter* handle;
std::vector<std::unique_ptr<DfgScope>> scopes;
// Does not belong in DataFlowGraphBuilder, but the old solver allows properties to escape the scope they were defined in,
// so we will need to be able to emulate this same behavior here too. We can kill this once we have better flow sensitivity.
DenseHashMap<const Def*, std::unordered_map<std::string, const Def*>> props{nullptr};
DfgScope* childScope(DfgScope* scope);
std::optional<DefId> use(DfgScope* scope, Symbol symbol, AstExpr* e);
DefId use(DefId def, AstExprIndexName* e);
void visit(DfgScope* scope, AstStatBlock* b);
void visitBlockWithoutChildScope(DfgScope* scope, AstStatBlock* b);
// TODO: visit type aliases
void visit(DfgScope* scope, AstStat* s);
void visit(DfgScope* scope, AstStatIf* i);
void visit(DfgScope* scope, AstStatWhile* w);
void visit(DfgScope* scope, AstStatRepeat* r);
void visit(DfgScope* scope, AstStatBreak* b);
void visit(DfgScope* scope, AstStatContinue* c);
void visit(DfgScope* scope, AstStatReturn* r);
void visit(DfgScope* scope, AstStatExpr* e);
void visit(DfgScope* scope, AstStatLocal* l);
void visit(DfgScope* scope, AstStatFor* f);
void visit(DfgScope* scope, AstStatForIn* f);
void visit(DfgScope* scope, AstStatAssign* a);
void visit(DfgScope* scope, AstStatCompoundAssign* c);
void visit(DfgScope* scope, AstStatFunction* f);
void visit(DfgScope* scope, AstStatLocalFunction* l);
ExpressionFlowGraph visitExpr(DfgScope* scope, AstExpr* e);
ExpressionFlowGraph visitExpr(DfgScope* scope, AstExprLocal* l);
ExpressionFlowGraph visitExpr(DfgScope* scope, AstExprGlobal* g);
ExpressionFlowGraph visitExpr(DfgScope* scope, AstExprCall* c);
ExpressionFlowGraph visitExpr(DfgScope* scope, AstExprIndexName* i);
ExpressionFlowGraph visitExpr(DfgScope* scope, AstExprIndexExpr* i);
ExpressionFlowGraph visitExpr(DfgScope* scope, AstExprFunction* f);
ExpressionFlowGraph visitExpr(DfgScope* scope, AstExprTable* t);
ExpressionFlowGraph visitExpr(DfgScope* scope, AstExprUnary* u);
ExpressionFlowGraph visitExpr(DfgScope* scope, AstExprBinary* b);
ExpressionFlowGraph visitExpr(DfgScope* scope, AstExprTypeAssertion* t);
ExpressionFlowGraph visitExpr(DfgScope* scope, AstExprIfElse* i);
ExpressionFlowGraph visitExpr(DfgScope* scope, AstExprInterpString* i);
// TODO: visitLValue
// TODO: visitTypes (because of typeof which has access to values namespace, needs unreachable scope)
// TODO: visitTypePacks (because of typeof which has access to values namespace, needs unreachable scope)
};
} // namespace Luau