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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/add_block_attribute.h"
#include <unordered_set>
#include <utility>
#include "src/tint/program_builder.h"
#include "src/tint/sem/variable.h"
#include "src/tint/utils/hashmap.h"
#include "src/tint/utils/hashset.h"
TINT_INSTANTIATE_TYPEINFO(tint::transform::AddBlockAttribute);
TINT_INSTANTIATE_TYPEINFO(tint::transform::AddBlockAttribute::BlockAttribute);
namespace tint::transform {
namespace {
bool IsUsedAsNonBuffer(const std::unordered_set<tint::ast::StorageClass>& uses) {
for (auto use : uses) {
if (!ast::IsHostShareable(use)) {
return true;
}
}
return false;
}
} // namespace
AddBlockAttribute::AddBlockAttribute() = default;
AddBlockAttribute::~AddBlockAttribute() = default;
void AddBlockAttribute::Run(CloneContext& ctx, const DataMap&, DataMap&) const {
auto& sem = ctx.src->Sem();
// Collect the set of structs that are nested in other types.
utils::Hashset<const sem::Struct*, 8> nested_structs;
for (auto* ty : ctx.src->Types()) {
Switch(
ty,
[&](const sem::Array* arr) {
if (auto* nested_str = arr->ElemType()->As<sem::Struct>()) {
nested_structs.Add(nested_str);
}
},
[&](const sem::Struct* str) {
for (auto* member : str->Members()) {
if (auto* nested_str = member->Type()->As<sem::Struct>()) {
nested_structs.Add(nested_str);
}
}
});
}
// A map from a type in the source program to a block-decorated wrapper that contains it in the
// destination program.
utils::Hashmap<const sem::Type*, const ast::Struct*, 8> wrapper_structs;
// Process global 'var' declarations that are buffers.
for (auto* global : ctx.src->AST().GlobalVariables()) {
auto* var = sem.Get(global);
if (!ast::IsHostShareable(var->StorageClass())) {
// Not declared in a host-sharable storage class
continue;
}
auto* ty = var->Type()->UnwrapRef();
auto* str = ty->As<sem::Struct>();
bool needs_wrapping =
!str || // Type is not a structure
nested_structs.Contains(str) || // Structure is nested by another type
IsUsedAsNonBuffer(str->StorageClassUsage()); // Structure is used as a non-buffer usage
if (needs_wrapping) {
const char* kMemberName = "inner";
// This is a non-struct or a struct that is nested somewhere else, so we
// need to wrap it first.
auto* wrapper = wrapper_structs.GetOrCreate(ty, [&] {
auto* block = ctx.dst->ASTNodes().Create<BlockAttribute>(ctx.dst->ID(),
ctx.dst->AllocateNodeID());
auto wrapper_name = ctx.src->Symbols().NameFor(global->symbol) + "_block";
auto* ret = ctx.dst->create<ast::Struct>(
ctx.dst->Symbols().New(wrapper_name),
utils::Vector{ctx.dst->Member(kMemberName, CreateASTTypeFor(ctx, ty))},
utils::Vector{block});
ctx.InsertBefore(ctx.src->AST().GlobalDeclarations(), global, ret);
return ret;
});
ctx.Replace(global->type, ctx.dst->ty.Of(wrapper));
// Insert a member accessor to get the original type from the wrapper at
// any usage of the original variable.
for (auto* user : var->Users()) {
ctx.Replace(user->Declaration(),
ctx.dst->MemberAccessor(ctx.Clone(global->symbol), kMemberName));
}
} else {
// Add a block attribute to this struct directly.
auto* block = ctx.dst->ASTNodes().Create<BlockAttribute>(ctx.dst->ID(),
ctx.dst->AllocateNodeID());
ctx.InsertFront(str->Declaration()->attributes, block);
}
}
ctx.Clone();
}
AddBlockAttribute::BlockAttribute::BlockAttribute(ProgramID pid, ast::NodeID nid)
: Base(pid, nid) {}
AddBlockAttribute::BlockAttribute::~BlockAttribute() = default;
std::string AddBlockAttribute::BlockAttribute::InternalName() const {
return "block";
}
const AddBlockAttribute::BlockAttribute* AddBlockAttribute::BlockAttribute::Clone(
CloneContext* ctx) const {
return ctx->dst->ASTNodes().Create<AddBlockAttribute::BlockAttribute>(
ctx->dst->ID(), ctx->dst->AllocateNodeID());
}
} // namespace tint::transform