166 строки
5.6 KiB
C++
166 строки
5.6 KiB
C++
// Copyright (c) 2018 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "source/reduce/remove_unused_instruction_reduction_opportunity_finder.h"
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#include "source/opcode.h"
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#include "source/opt/instruction.h"
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#include "source/reduce/remove_instruction_reduction_opportunity.h"
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namespace spvtools {
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namespace reduce {
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RemoveUnusedInstructionReductionOpportunityFinder::
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RemoveUnusedInstructionReductionOpportunityFinder(
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bool remove_constants_and_undefs)
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: remove_constants_and_undefs_(remove_constants_and_undefs) {}
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std::vector<std::unique_ptr<ReductionOpportunity>>
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RemoveUnusedInstructionReductionOpportunityFinder::GetAvailableOpportunities(
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opt::IRContext* context) const {
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std::vector<std::unique_ptr<ReductionOpportunity>> result;
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for (auto& inst : context->module()->debugs1()) {
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if (context->get_def_use_mgr()->NumUses(&inst) > 0) {
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continue;
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}
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result.push_back(MakeUnique<RemoveInstructionReductionOpportunity>(&inst));
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}
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for (auto& inst : context->module()->debugs2()) {
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if (context->get_def_use_mgr()->NumUses(&inst) > 0) {
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continue;
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}
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result.push_back(MakeUnique<RemoveInstructionReductionOpportunity>(&inst));
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}
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for (auto& inst : context->module()->debugs3()) {
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if (context->get_def_use_mgr()->NumUses(&inst) > 0) {
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continue;
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}
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result.push_back(MakeUnique<RemoveInstructionReductionOpportunity>(&inst));
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}
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for (auto& inst : context->module()->ext_inst_debuginfo()) {
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if (context->get_def_use_mgr()->NumUses(&inst) > 0) {
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continue;
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}
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result.push_back(MakeUnique<RemoveInstructionReductionOpportunity>(&inst));
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}
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for (auto& inst : context->module()->types_values()) {
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if (!remove_constants_and_undefs_ &&
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spvOpcodeIsConstantOrUndef(inst.opcode())) {
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continue;
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}
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if (!OnlyReferencedByIntimateDecorationOrEntryPointInterface(context,
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inst)) {
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continue;
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}
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result.push_back(MakeUnique<RemoveInstructionReductionOpportunity>(&inst));
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}
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for (auto& inst : context->module()->annotations()) {
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if (context->get_def_use_mgr()->NumUsers(&inst) > 0) {
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continue;
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}
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if (!IsIndependentlyRemovableDecoration(inst)) {
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continue;
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}
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result.push_back(MakeUnique<RemoveInstructionReductionOpportunity>(&inst));
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}
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for (auto& function : *context->module()) {
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for (auto& block : function) {
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for (auto& inst : block) {
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if (context->get_def_use_mgr()->NumUses(&inst) > 0) {
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continue;
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}
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if (!remove_constants_and_undefs_ &&
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spvOpcodeIsConstantOrUndef(inst.opcode())) {
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continue;
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}
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if (spvOpcodeIsBlockTerminator(inst.opcode()) ||
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inst.opcode() == SpvOpSelectionMerge ||
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inst.opcode() == SpvOpLoopMerge) {
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// In this reduction pass we do not want to affect static
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// control flow.
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continue;
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}
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// Given that we're in a block, we should only get here if
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// the instruction is not directly related to control flow;
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// i.e., it's some straightforward instruction with an
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// unused result, like an arithmetic operation or function
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// call.
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result.push_back(
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MakeUnique<RemoveInstructionReductionOpportunity>(&inst));
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}
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}
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}
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return result;
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}
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std::string RemoveUnusedInstructionReductionOpportunityFinder::GetName() const {
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return "RemoveUnusedInstructionReductionOpportunityFinder";
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}
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bool RemoveUnusedInstructionReductionOpportunityFinder::
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OnlyReferencedByIntimateDecorationOrEntryPointInterface(
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opt::IRContext* context, const opt::Instruction& inst) const {
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return context->get_def_use_mgr()->WhileEachUse(
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&inst, [this](opt::Instruction* user, uint32_t use_index) -> bool {
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return (user->IsDecoration() &&
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!IsIndependentlyRemovableDecoration(*user)) ||
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(user->opcode() == SpvOpEntryPoint && use_index > 2);
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});
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}
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bool RemoveUnusedInstructionReductionOpportunityFinder::
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IsIndependentlyRemovableDecoration(const opt::Instruction& inst) const {
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uint32_t decoration;
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switch (inst.opcode()) {
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case SpvOpDecorate:
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case SpvOpDecorateId:
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case SpvOpDecorateString:
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decoration = inst.GetSingleWordInOperand(1u);
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break;
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case SpvOpMemberDecorate:
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case SpvOpMemberDecorateString:
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decoration = inst.GetSingleWordInOperand(2u);
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break;
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default:
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// The instruction is not a decoration. It is legitimate for this to be
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// reached: it allows the method to be invoked on arbitrary instructions.
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return false;
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}
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// We conservatively only remove specific decorations that we believe will
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// not change the shader interface, will not make the shader invalid, will
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// actually be found in practice, etc.
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switch (decoration) {
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case SpvDecorationRelaxedPrecision:
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case SpvDecorationNoSignedWrap:
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case SpvDecorationNoContraction:
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case SpvDecorationNoUnsignedWrap:
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case SpvDecorationUserSemantic:
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return true;
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default:
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return false;
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}
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}
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} // namespace reduce
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} // namespace spvtools
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