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// Copyright (c) 2017 Pierre Moreau
//
// 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 "source/opt/remove_duplicates_pass.h"
#include <algorithm>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#include "source/opcode.h"
#include "source/opt/decoration_manager.h"
#include "source/opt/ir_context.h"
namespace spvtools {
namespace opt {
Pass::Status RemoveDuplicatesPass::Process() {
bool modified = RemoveDuplicateCapabilities();
modified |= RemoveDuplicatesExtInstImports();
modified |= RemoveDuplicateTypes();
modified |= RemoveDuplicateDecorations();
return modified ? Status::SuccessWithChange : Status::SuccessWithoutChange;
}
bool RemoveDuplicatesPass::RemoveDuplicateCapabilities() const {
bool modified = false;
if (context()->capabilities().empty()) {
return modified;
}
std::unordered_set<uint32_t> capabilities;
for (auto* i = &*context()->capability_begin(); i;) {
auto res = capabilities.insert(i->GetSingleWordOperand(0u));
if (res.second) {
// Never seen before, keep it.
i = i->NextNode();
} else {
// It's a duplicate, remove it.
i = context()->KillInst(i);
modified = true;
}
}
return modified;
}
bool RemoveDuplicatesPass::RemoveDuplicatesExtInstImports() const {
bool modified = false;
if (context()->ext_inst_imports().empty()) {
return modified;
}
std::unordered_map<std::string, spv::Id> ext_inst_imports;
for (auto* i = &*context()->ext_inst_import_begin(); i;) {
auto res = ext_inst_imports.emplace(i->GetInOperand(0u).AsString(),
i->result_id());
if (res.second) {
// Never seen before, keep it.
i = i->NextNode();
} else {
// It's a duplicate, remove it.
context()->ReplaceAllUsesWith(i->result_id(), res.first->second);
i = context()->KillInst(i);
modified = true;
}
}
return modified;
}
bool RemoveDuplicatesPass::RemoveDuplicateTypes() const {
bool modified = false;
if (context()->types_values().empty()) {
return modified;
}
analysis::TypeManager type_manager(context()->consumer(), context());
std::vector<Instruction*> visited_types;
std::vector<analysis::ForwardPointer> visited_forward_pointers;
std::vector<Instruction*> to_delete;
for (auto* i = &*context()->types_values_begin(); i; i = i->NextNode()) {
const bool is_i_forward_pointer =
i->opcode() == spv::Op::OpTypeForwardPointer;
// We only care about types.
if (!spvOpcodeGeneratesType(i->opcode()) && !is_i_forward_pointer) {
continue;
}
if (!is_i_forward_pointer) {
// Is the current type equal to one of the types we have already visited?
spv::Id id_to_keep = 0u;
analysis::Type* i_type = type_manager.GetType(i->result_id());
assert(i_type);
// TODO(dneto0): Use a trie to avoid quadratic behaviour? Extract the
// ResultIdTrie from unify_const_pass.cpp for this.
for (auto j : visited_types) {
analysis::Type* j_type = type_manager.GetType(j->result_id());
assert(j_type);
if (*i_type == *j_type) {
id_to_keep = j->result_id();
break;
}
}
if (id_to_keep == 0u) {
// This is a never seen before type, keep it around.
visited_types.emplace_back(i);
} else {
// The same type has already been seen before, remove this one.
context()->KillNamesAndDecorates(i->result_id());
context()->ReplaceAllUsesWith(i->result_id(), id_to_keep);
modified = true;
to_delete.emplace_back(i);
}
} else {
analysis::ForwardPointer i_type(
i->GetSingleWordInOperand(0u),
(spv::StorageClass)i->GetSingleWordInOperand(1u));
i_type.SetTargetPointer(
type_manager.GetType(i_type.target_id())->AsPointer());
// TODO(dneto0): Use a trie to avoid quadratic behaviour? Extract the
// ResultIdTrie from unify_const_pass.cpp for this.
const bool found_a_match =
std::find(std::begin(visited_forward_pointers),
std::end(visited_forward_pointers),
i_type) != std::end(visited_forward_pointers);
if (!found_a_match) {
// This is a never seen before type, keep it around.
visited_forward_pointers.emplace_back(i_type);
} else {
// The same type has already been seen before, remove this one.
modified = true;
to_delete.emplace_back(i);
}
}
}
for (auto i : to_delete) {
context()->KillInst(i);
}
return modified;
}
// TODO(pierremoreau): Duplicate decoration groups should be removed. For
// example, in
// OpDecorate %1 Constant
// %1 = OpDecorationGroup
// OpDecorate %2 Constant
// %2 = OpDecorationGroup
// OpGroupDecorate %1 %3
// OpGroupDecorate %2 %4
// group %2 could be removed.
bool RemoveDuplicatesPass::RemoveDuplicateDecorations() const {
bool modified = false;
std::vector<const Instruction*> visited_decorations;
analysis::DecorationManager decoration_manager(context()->module());
for (auto* i = &*context()->annotation_begin(); i;) {
// Is the current decoration equal to one of the decorations we have
// already visited?
bool already_visited = false;
// TODO(dneto0): Use a trie to avoid quadratic behaviour? Extract the
// ResultIdTrie from unify_const_pass.cpp for this.
for (const Instruction* j : visited_decorations) {
if (decoration_manager.AreDecorationsTheSame(&*i, j, false)) {
already_visited = true;
break;
}
}
if (!already_visited) {
// This is a never seen before decoration, keep it around.
visited_decorations.emplace_back(&*i);
i = i->NextNode();
} else {
// The same decoration has already been seen before, remove this one.
modified = true;
i = context()->KillInst(i);
}
}
return modified;
}
} // namespace opt
} // namespace spvtools