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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// -*- mode: C++ -*-
//
// Copyright 2023-2024 Google LLC
//
// Licensed under the Apache License v2.0 with LLVM Exceptions (the
// "License"); you may not use this file except in compliance with the
// License. You may obtain a copy of the License at
//
// https://llvm.org/LICENSE.txt
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Author: Aleksei Vetrov
#include "type_normalisation.h"
#include <map>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#include "graph.h"
namespace stg {
namespace {
struct ResolveQualifiedChain {
ResolveQualifiedChain(const Graph& graph,
std::unordered_map<Id, Id>& resolved)
: graph(graph), resolved(resolved) {}
Id operator()(Id node_id) {
return graph.Apply<Id>(*this, node_id, node_id);
}
Id operator()(const Qualified& x, Id node_id) {
auto [it, emplaced] = resolved.emplace(node_id, Id::kInvalid);
if (!emplaced) {
Check(it->second != Id::kInvalid) << "qualified cycle detected";
return it->second;
}
return it->second = (*this)(x.qualified_type_id);
}
template <typename Node>
Id operator()(const Node&, Id node_id) {
return node_id;
}
const Graph& graph;
std::unordered_map<Id, Id>& resolved;
};
// Traverse rooted graph and produce mapping from qualified type to
// non-qualified. Produced keys should not intersect with values.
// It also collects all functions seen during traversal.
struct FindQualifiedTypesAndFunctions {
FindQualifiedTypesAndFunctions(const Graph& graph,
std::unordered_map<Id, Id>& resolved,
std::unordered_set<Id>& functions)
: graph(graph),
resolved(resolved),
functions(functions),
resolve_qualified_chain(graph, resolved) {}
void operator()(Id id) {
if (seen.insert(id).second) {
graph.Apply<void>(*this, id, id);
}
}
void operator()(const std::vector<Id>& ids) {
for (const auto& id : ids) {
(*this)(id);
}
}
void operator()(const std::map<std::string, Id>& x) {
for (const auto& [_, id] : x) {
(*this)(id);
}
}
void operator()(const Special&, Id) {}
void operator()(const PointerReference& x, Id) {
(*this)(x.pointee_type_id);
}
void operator()(const PointerToMember& x, Id) {
(*this)(x.containing_type_id);
(*this)(x.pointee_type_id);
}
// Typedefs are not considered when looking for useless qualifiers.
void operator()(const Typedef& x, Id) {
(*this)(x.referred_type_id);
}
void operator()(const Qualified&, Id node_id) {
(*this)(resolve_qualified_chain(node_id));
}
void operator()(const Primitive&, Id) {}
void operator()(const Array& x, Id) {
(*this)(x.element_type_id);
}
void operator()(const BaseClass& x, Id) {
(*this)(x.type_id);
}
void operator()(const Method& x, Id) {
(*this)(x.type_id);
}
void operator()(const Member& x, Id) {
(*this)(x.type_id);
}
void operator()(const VariantMember& x, Id) {
(*this)(x.type_id);
}
void operator()(const StructUnion& x, Id) {
if (x.definition.has_value()) {
auto& definition = x.definition.value();
(*this)(definition.base_classes);
(*this)(definition.methods);
(*this)(definition.members);
}
}
void operator()(const Enumeration& x, Id) {
if (x.definition.has_value()) {
(*this)(x.definition->underlying_type_id);
}
}
void operator()(const Variant& x, Id) {
if (x.discriminant.has_value()) {
(*this)(x.discriminant.value());
}
(*this)(x.members);
}
void operator()(const Function& x, Id node_id) {
functions.emplace(node_id);
for (auto& id : x.parameters) {
(*this)(id);
}
(*this)(x.return_type_id);
}
void operator()(const ElfSymbol& x, Id) {
if (x.type_id) {
(*this)(*x.type_id);
}
}
void operator()(const Interface& x, Id) {
(*this)(x.symbols);
(*this)(x.types);
}
const Graph& graph;
std::unordered_map<Id, Id>& resolved;
std::unordered_set<Id>& functions;
std::unordered_set<Id> seen;
ResolveQualifiedChain resolve_qualified_chain;
};
// Remove qualifiers from function parameters and return type.
// "resolved" mapping should have resolutions from qualified type to
// non-qualified. Thus, keys and values should not intersect.
struct RemoveFunctionQualifiers {
RemoveFunctionQualifiers(Graph& graph,
const std::unordered_map<Id, Id>& resolved)
: graph(graph), resolved(resolved) {}
void operator()(Id id) {
graph.Apply<void>(*this, id);
}
void operator()(Function& x) {
for (auto& id : x.parameters) {
RemoveQualifiers(id);
}
RemoveQualifiers(x.return_type_id);
}
template<typename Node>
void operator()(Node&) {
Die() << "only functions should have qualifiers substituted";
}
void RemoveQualifiers(Id& id) {
const auto it = resolved.find(id);
if (it != resolved.end()) {
id = it->second;
Check(!resolved.count(id)) << "qualifier was resolved to qualifier";
}
}
Graph& graph;
const std::unordered_map<Id, Id>& resolved;
};
} // namespace
void RemoveUselessQualifiers(Graph& graph, Id root) {
std::unordered_map<Id, Id> resolved;
std::unordered_set<Id> functions;
FindQualifiedTypesAndFunctions(graph, resolved, functions)(root);
RemoveFunctionQualifiers remove_qualifiers(graph, resolved);
for (const auto& id : functions) {
remove_qualifiers(id);
}
}
} // namespace stg
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