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// Copyright 2021 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// 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.
#include "src/tint/transform/unshadow.h"
#include <memory>
#include <unordered_map>
#include <utility>
#include "src/tint/program_builder.h"
#include "src/tint/sem/block_statement.h"
#include "src/tint/sem/function.h"
#include "src/tint/sem/statement.h"
#include "src/tint/sem/variable.h"
TINT_INSTANTIATE_TYPEINFO(tint::transform::Unshadow);
namespace tint::transform {
/// The PIMPL state for the Unshadow transform
struct Unshadow::State {
/// The clone context
CloneContext& ctx;
/// Constructor
/// @param context the clone context
explicit State(CloneContext& context) : ctx(context) {}
/// Performs the transformation
void Run() {
auto& sem = ctx.src->Sem();
// Maps a variable to its new name.
std::unordered_map<const sem::Variable*, Symbol> renamed_to;
auto rename = [&](const sem::Variable* v) -> const ast::Variable* {
auto* decl = v->Declaration();
auto name = ctx.src->Symbols().NameFor(decl->symbol);
auto symbol = ctx.dst->Symbols().New(name);
renamed_to.emplace(v, symbol);
auto source = ctx.Clone(decl->source);
auto* type = ctx.Clone(decl->type);
auto* constructor = ctx.Clone(decl->constructor);
auto attributes = ctx.Clone(decl->attributes);
return Switch(
decl, //
[&](const ast::Var* var) {
return ctx.dst->Var(source, symbol, type, var->declared_storage_class,
var->declared_access, constructor, attributes);
},
[&](const ast::Let*) {
return ctx.dst->Let(source, symbol, type, constructor, attributes);
},
[&](const ast::Const*) {
return ctx.dst->Const(source, symbol, type, constructor, attributes);
},
[&](const ast::Parameter*) {
return ctx.dst->Param(source, symbol, type, attributes);
},
[&](Default) {
TINT_ICE(Transform, ctx.dst->Diagnostics())
<< "unexpected variable type: " << decl->TypeInfo().name;
return nullptr;
});
};
ctx.ReplaceAll([&](const ast::Variable* v) -> const ast::Variable* {
if (auto* local = sem.Get<sem::LocalVariable>(v)) {
if (local->Shadows()) {
return rename(local);
}
}
if (auto* param = sem.Get<sem::Parameter>(v)) {
if (param->Shadows()) {
return rename(param);
}
}
return nullptr;
});
ctx.ReplaceAll(
[&](const ast::IdentifierExpression* ident) -> const tint::ast::IdentifierExpression* {
if (auto* user = sem.Get<sem::VariableUser>(ident)) {
auto it = renamed_to.find(user->Variable());
if (it != renamed_to.end()) {
return ctx.dst->Expr(it->second);
}
}
return nullptr;
});
ctx.Clone();
}
};
Unshadow::Unshadow() = default;
Unshadow::~Unshadow() = default;
void Unshadow::Run(CloneContext& ctx, const DataMap&, DataMap&) const {
State(ctx).Run();
}
} // namespace tint::transform