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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/transform/single_entry_point.h"
#include <unordered_set>
#include <utility>
#include "src/program_builder.h"
#include "src/sem/function.h"
#include "src/sem/variable.h"
TINT_INSTANTIATE_TYPEINFO(tint::transform::SingleEntryPoint::Config);
namespace tint {
namespace transform {
SingleEntryPoint::SingleEntryPoint() = default;
SingleEntryPoint::~SingleEntryPoint() = default;
Output SingleEntryPoint::Run(const Program* in, const DataMap& data) {
ProgramBuilder out;
auto* cfg = data.Get<Config>();
if (cfg == nullptr) {
out.Diagnostics().add_error("missing transform data for SingleEntryPoint");
return Output(Program(std::move(out)));
}
// Find the target entry point.
ast::Function* entry_point = nullptr;
for (auto* f : in->AST().Functions()) {
if (!f->IsEntryPoint()) {
continue;
}
if (in->Symbols().NameFor(f->symbol()) == cfg->entry_point_name) {
entry_point = f;
break;
}
}
if (entry_point == nullptr) {
out.Diagnostics().add_error("entry point '" + cfg->entry_point_name +
"' not found");
return Output(Program(std::move(out)));
}
CloneContext ctx(&out, in);
auto* sem = in->Sem().Get(entry_point);
// Build set of referenced module-scope variables for faster lookups later.
std::unordered_set<const ast::Variable*> referenced_vars;
for (auto* var : sem->ReferencedModuleVariables()) {
referenced_vars.emplace(var->Declaration());
}
// Clone any module-scope variables, types, and functions that are statically
// referenced by the target entry point.
for (auto* decl : in->AST().GlobalDeclarations()) {
if (auto* ty = decl->As<ast::TypeDecl>()) {
// TODO(jrprice): Strip unused types.
out.AST().AddTypeDecl(ctx.Clone(ty));
} else if (auto* var = decl->As<ast::Variable>()) {
if (var->is_const() || referenced_vars.count(var)) {
out.AST().AddGlobalVariable(ctx.Clone(var));
}
} else if (auto* func = decl->As<ast::Function>()) {
if (in->Sem().Get(func)->HasAncestorEntryPoint(entry_point->symbol())) {
out.AST().AddFunction(ctx.Clone(func));
}
} else {
TINT_UNREACHABLE(out.Diagnostics())
<< "unhandled global declaration: " << decl->TypeInfo().name;
return Output(Program(std::move(out)));
}
}
// Clone the entry point.
out.AST().AddFunction(ctx.Clone(entry_point));
return Output(Program(std::move(out)));
}
SingleEntryPoint::Config::Config(std::string entry_point)
: entry_point_name(entry_point) {}
SingleEntryPoint::Config::Config(const Config&) = default;
SingleEntryPoint::Config::~Config() = default;
SingleEntryPoint::Config& SingleEntryPoint::Config::operator=(const Config&) =
default;
} // namespace transform
} // namespace tint