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// Copyright 2022 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/substitute_override.h"
#include <functional>
#include <utility>
#include "src/tint/program_builder.h"
#include "src/tint/sem/builtin.h"
#include "src/tint/sem/index_accessor_expression.h"
#include "src/tint/sem/variable.h"
TINT_INSTANTIATE_TYPEINFO(tint::transform::SubstituteOverride);
TINT_INSTANTIATE_TYPEINFO(tint::transform::SubstituteOverride::Config);
namespace tint::transform {
namespace {
bool ShouldRun(const Program* program) {
for (auto* node : program->AST().GlobalVariables()) {
if (node->Is<ast::Override>()) {
return true;
}
}
return false;
}
} // namespace
SubstituteOverride::SubstituteOverride() = default;
SubstituteOverride::~SubstituteOverride() = default;
Transform::ApplyResult SubstituteOverride::Apply(const Program* src,
const DataMap& config,
DataMap&) const {
ProgramBuilder b;
CloneContext ctx{&b, src, /* auto_clone_symbols */ true};
const auto* data = config.Get<Config>();
if (!data) {
b.Diagnostics().add_error(diag::System::Transform, "Missing override substitution data");
return Program(std::move(b));
}
if (!ShouldRun(ctx.src)) {
return SkipTransform;
}
ctx.ReplaceAll([&](const ast::Override* w) -> const ast::Const* {
auto* sem = ctx.src->Sem().Get(w);
auto source = ctx.Clone(w->source);
auto sym = ctx.Clone(w->symbol);
auto* ty = ctx.Clone(w->type);
// No replacement provided, just clone the override node as a const.
auto iter = data->map.find(sem->OverrideId());
if (iter == data->map.end()) {
if (!w->initializer) {
b.Diagnostics().add_error(
diag::System::Transform,
"Initializer not provided for override, and override not overridden.");
return nullptr;
}
return b.Const(source, sym, ty, ctx.Clone(w->initializer));
}
auto value = iter->second;
auto* ctor = Switch(
sem->Type(),
[&](const type::Bool*) { return b.Expr(!std::equal_to<double>()(value, 0.0)); },
[&](const type::I32*) { return b.Expr(i32(value)); },
[&](const type::U32*) { return b.Expr(u32(value)); },
[&](const type::F32*) { return b.Expr(f32(value)); },
[&](const type::F16*) { return b.Expr(f16(value)); });
if (!ctor) {
b.Diagnostics().add_error(diag::System::Transform,
"Failed to create override-expression");
return nullptr;
}
return b.Const(source, sym, ty, ctor);
});
// Ensure that objects that are indexed with an override-expression are materialized.
// If the object is not materialized, and the 'override' variable is turned to a 'const', the
// resulting type of the index may change. See: crbug.com/tint/1697.
ctx.ReplaceAll(
[&](const ast::IndexAccessorExpression* expr) -> const ast::IndexAccessorExpression* {
if (auto* sem = src->Sem().Get(expr)) {
if (auto* access = sem->UnwrapMaterialize()->As<sem::IndexAccessorExpression>()) {
if (access->Object()->UnwrapMaterialize()->Type()->HoldsAbstract() &&
access->Index()->Stage() == sem::EvaluationStage::kOverride) {
auto* obj = b.Call(sem::str(sem::BuiltinType::kTintMaterialize),
ctx.Clone(expr->object));
return b.IndexAccessor(obj, ctx.Clone(expr->index));
}
}
}
return nullptr;
});
ctx.Clone();
return Program(std::move(b));
}
SubstituteOverride::Config::Config() = default;
SubstituteOverride::Config::Config(const Config&) = default;
SubstituteOverride::Config::~Config() = default;
SubstituteOverride::Config& SubstituteOverride::Config::operator=(const Config&) = default;
} // namespace tint::transform