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iss: Add strategy analysis infrastructure
Adds the infrastructure for instruction analysis. It obtains facts about an instruction, and strategy evaluators use them to decide whether its strategy is viable for the given instruction.
1 parent f4ccbc6 commit 23caac1

24 files changed

Lines changed: 2134 additions & 82 deletions

‎vadl/main/vadl/dump/infoEnrichers/ViamEnricherCollection.java‎

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import vadl.dump.InfoEnricher;
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import vadl.dump.InfoUtils;
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import vadl.dump.entities.DefinitionEntity;
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import vadl.iss.passes.extensions.InstrExecPlan;
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import vadl.iss.passes.extensions.InstrInfo;
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import vadl.utils.SourceLocation;
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import vadl.viam.DefProp;
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import vadl.viam.Encoding;
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entity.addInfo(info);
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});
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public static InfoEnricher VECTOR_TCG_PLAN_SUPPLIER_TAGS =
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forType(DefinitionEntity.class, (entity, passResult) -> {
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if (!(entity.origin() instanceof Instruction instruction)) {
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return;
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}
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var info = instruction.extension(InstrInfo.class);
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if (info == null || info.executionPlan() == null) {
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return;
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}
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var executionPlan = info.executionPlan();
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entity.addInfo(Info.Tag.of("SelectedExecutionStrategy",
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executionPlan.selectedStrategy().name()));
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var directGvec = executionPlan.evaluation(
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InstrExecPlan.StrategyKind.DIRECT_GVEC);
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if (directGvec == null) {
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return;
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}
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entity.addInfo(Info.Tag.of("DirectGvecStatus", directGvec.status().name()));
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entity.addInfo(Info.Tag.of("DirectGvecIssues",
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directGvec.issues().isEmpty()
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? "-"
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: directGvec.issues().stream()
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.map(issue -> issue.code())
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.collect(Collectors.joining(", "))));
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});
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public static InfoEnricher BEHAVIOR_NO_LOCATION_EXPANDABLE =
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forType(DefinitionEntity.class, (entity, passResult) -> {
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VERIFY_SUPPLIER_EXPANDABLE,
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SOURCE_CODE_SUPPLIER_EXPANDABLE,
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RESOURCE_ACCESS_SUPPLIER_EXPANDABLE,
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VECTOR_TCG_PLAN_SUPPLIER_TAGS,
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BEHAVIOR_NO_LOCATION_EXPANDABLE,
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STAGE_ORDER_SUPPLIER,
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OPERATION_INSTRUCTIONS_SUPPLIER_EXPANDABLE,

‎vadl/main/vadl/iss/passes/common/IssExecStrategyPass.java‎

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This file was deleted.

‎vadl/main/vadl/iss/passes/common/planning/InstructionExecutionPlanner.java‎

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// SPDX-FileCopyrightText : © 2026 TU Wien <vadl@tuwien.ac.at>
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// SPDX-License-Identifier: GPL-3.0-or-later
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package vadl.iss.passes.common.planning;
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import java.util.Comparator;
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import java.util.List;
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import vadl.iss.passes.extensions.InstrExecPlan;
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import vadl.iss.passes.extensions.InstrExecPlan.StrategyEvaluation;
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import vadl.iss.passes.extensions.InstrExecPlan.StrategyKind;
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import vadl.viam.Instruction;
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/**
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* Evaluates all configured execution strategies and selects the best viable one.
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*/
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final class InstructionExecutionPlanner {
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private final List<StrategyEvaluator> evaluators;
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InstructionExecutionPlanner(List<StrategyEvaluator> evaluators) {
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this.evaluators = List.copyOf(evaluators);
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}
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/**
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* Plans instruction execution by evaluating all strategies and selecting the best viable one.
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*/
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InstrExecPlan plan(Instruction instruction) {
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var evaluations = evaluators.stream()
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.map(evaluator -> evaluator.evaluate(instruction))
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.toList();
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var selected = evaluations.stream()
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.filter(StrategyEvaluation::isViable)
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.min(Comparator
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.comparingInt(StrategyEvaluation::estimatedCost)
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.thenComparingInt(evaluation -> strategyPriority(evaluation.strategy())))
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.orElseThrow(() -> new IllegalStateException(
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"Expected at least one viable execution strategy for " + instruction.simpleName()));
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return new InstrExecPlan(evaluations, selected);
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}
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private int strategyPriority(StrategyKind strategy) {
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return switch (strategy) {
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case DIRECT_GVEC -> 0;
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case TCG_SCALAR -> 1;
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case HELPER_CALL -> 2;
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};
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}
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}

‎vadl/main/vadl/iss/passes/common/planning/IssExecStrategyPass.java‎

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// SPDX-FileCopyrightText : © 2026 TU Wien <vadl@tuwien.ac.at>
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// SPDX-License-Identifier: GPL-3.0-or-later
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package vadl.iss.passes.common.planning;
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import static vadl.iss.passes.TcgPassUtils.instrInfo;
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import java.io.IOException;
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import java.util.List;
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import javax.annotation.Nullable;
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import vadl.configuration.IssConfiguration;
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import vadl.iss.passes.AbstractIssPass;
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import vadl.iss.passes.common.planning.evaluators.DirectGvecStrategyEvaluator;
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import vadl.iss.passes.common.planning.evaluators.HelperCallStrategyEvaluator;
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import vadl.iss.passes.common.planning.evaluators.TcgScalarStrategyEvaluator;
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import vadl.pass.PassName;
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import vadl.pass.PassResults;
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import vadl.viam.Specification;
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/**
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* Computes and stores instruction execution plans plus the currently supported backend strategy.
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*
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* <p>The selected execution plan is the backend-independent source of truth. The legacy
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* {@link vadl.iss.passes.extensions.InstrInfo.ExecStrategy} is derived from the selected plan so
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* existing code generation can keep treating unsupported non-scalar strategies as helper calls.</p>
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*/
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public class IssExecStrategyPass extends AbstractIssPass {
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private final InstructionExecutionPlanner executionPlanner;
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public IssExecStrategyPass(IssConfiguration configuration) {
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super(configuration);
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this.executionPlanner = new InstructionExecutionPlanner(defaultEvaluators());
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}
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@Override
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public PassName getName() {
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return PassName.of("ISS Exec Strategy Classification");
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}
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@Override
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public @Nullable Object execute(PassResults passResults, Specification viam) throws IOException {
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if (viam.isa().isEmpty()) {
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return null;
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}
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var isa = viam.isa().get();
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isa.ownInstructions().forEach(
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instr -> instrInfo(instr).setExecutionPlan(executionPlanner.plan(instr))
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);
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return null;
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}
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private List<StrategyEvaluator> defaultEvaluators() {
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return List.of(
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new DirectGvecStrategyEvaluator(),
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new TcgScalarStrategyEvaluator(),
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new HelperCallStrategyEvaluator()
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);
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}
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}

‎vadl/main/vadl/iss/passes/common/planning/StrategyEvaluator.java‎

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// SPDX-FileCopyrightText : © 2026 TU Wien <vadl@tuwien.ac.at>
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// SPDX-License-Identifier: GPL-3.0-or-later
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package vadl.iss.passes.common.planning;
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import vadl.iss.passes.extensions.InstrExecPlan.StrategyEvaluation;
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import vadl.viam.Instruction;
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/**
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* Evaluates whether one execution strategy can implement a given instruction.
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*/
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public interface StrategyEvaluator {
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/**
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* Evaluates the strategy for the given instruction.
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*/
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StrategyEvaluation evaluate(Instruction instruction);
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}

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