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// Copyright 2021 The Dawn & Tint Authors
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "src/tint/lang/wgsl/ast/transform/single_entry_point.h"
#include <unordered_set>
#include <utility>
#include "src/tint/lang/wgsl/program/clone_context.h"
#include "src/tint/lang/wgsl/program/program_builder.h"
#include "src/tint/lang/wgsl/resolver/resolve.h"
#include "src/tint/lang/wgsl/sem/array.h"
#include "src/tint/lang/wgsl/sem/function.h"
#include "src/tint/lang/wgsl/sem/variable.h"
#include "src/tint/utils/rtti/switch.h"
TINT_INSTANTIATE_TYPEINFO(tint::ast::transform::SingleEntryPoint);
TINT_INSTANTIATE_TYPEINFO(tint::ast::transform::SingleEntryPoint::Config);
namespace tint::ast::transform {
SingleEntryPoint::SingleEntryPoint() = default;
SingleEntryPoint::~SingleEntryPoint() = default;
Transform::ApplyResult SingleEntryPoint::Apply(const Program& src,
const DataMap& inputs,
DataMap&) const {
ProgramBuilder b;
program::CloneContext ctx{&b, &src, /* auto_clone_symbols */ true};
auto* cfg = inputs.Get<Config>();
if (cfg == nullptr) {
b.Diagnostics().AddError(diag::System::Transform, Source{})
<< "missing transform data for " << TypeInfo().name;
return resolver::Resolve(b);
}
// Find the target entry point.
const Function* entry_point = nullptr;
for (auto* f : src.AST().Functions()) {
if (!f->IsEntryPoint()) {
continue;
}
if (f->name->symbol.Name() == cfg->entry_point_name) {
entry_point = f;
break;
}
}
if (entry_point == nullptr) {
b.Diagnostics().AddError(diag::System::Transform, Source{})
<< "entry point '" << cfg->entry_point_name << "' not found";
return resolver::Resolve(b);
}
auto& sem = src.Sem();
auto& referenced_vars = sem.Get(entry_point)->TransitivelyReferencedGlobals();
// Clone any module-scope variables, types, and functions that are statically referenced by the
// target entry point.
for (auto* decl : src.AST().GlobalDeclarations()) {
Switch(
decl, //
[&](const TypeDecl* ty) {
// Strip aliases that reference unused override declarations.
if (auto* arr = sem.Get(ty)->As<sem::Array>()) {
for (auto* o : arr->TransitivelyReferencedOverrides()) {
if (!referenced_vars.Contains(o)) {
return;
}
}
}
// TODO(jrprice): Strip other unused types.
b.AST().AddTypeDecl(ctx.Clone(ty));
},
[&](const Override* override) {
if (referenced_vars.Contains(sem.Get(override))) {
if (!HasAttribute<IdAttribute>(override->attributes)) {
// If the override doesn't already have an @id() attribute, add one
// so that its allocated ID so that it won't be affected by other
// stripped away overrides
auto* global = sem.Get(override);
const auto* id = b.Id(global->Attributes().override_id.value());
ctx.InsertFront(override->attributes, id);
}
b.AST().AddGlobalVariable(ctx.Clone(override));
}
},
[&](const Var* var) {
if (referenced_vars.Contains(sem.Get<sem::GlobalVariable>(var))) {
b.AST().AddGlobalVariable(ctx.Clone(var));
}
},
[&](const Const* c) {
// Always keep 'const' declarations, as these can be used by attributes and array
// sizes, which are not tracked as transitively used by functions. They also don't
// typically get emitted by the backend unless they're actually used.
b.AST().AddGlobalVariable(ctx.Clone(c));
},
[&](const Function* func) {
if (sem.Get(func)->HasAncestorEntryPoint(entry_point->name->symbol)) {
b.AST().AddFunction(ctx.Clone(func));
}
},
[&](const Enable* ext) { b.AST().AddEnable(ctx.Clone(ext)); },
[&](const Requires*) {
// Drop requires directives as they are optional, and it's non-trivial to determine
// which features are needed for which entry points.
},
[&](const ConstAssert* ca) { b.AST().AddConstAssert(ctx.Clone(ca)); },
[&](const DiagnosticDirective* d) { b.AST().AddDiagnosticDirective(ctx.Clone(d)); }, //
TINT_ICE_ON_NO_MATCH);
}
// Clone the entry point.
b.AST().AddFunction(ctx.Clone(entry_point));
return resolver::Resolve(b);
}
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 tint::ast::transform