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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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package org.graalvm.compiler.lir.alloc.trace;
import java.util.List;
import org.graalvm.compiler.core.common.alloc.Trace;
import org.graalvm.compiler.core.common.alloc.TraceBuilderResult;
import org.graalvm.compiler.core.common.cfg.AbstractBlockBase;
import org.graalvm.compiler.lir.LIR;
import org.graalvm.compiler.lir.LIRInstruction;
import org.graalvm.compiler.lir.StandardOp.JumpOp;
import org.graalvm.compiler.lir.StandardOp.LabelOp;
import jdk.vm.ci.meta.Value;
public class TraceUtil {
public static AbstractBlockBase<?> getBestTraceInterPredecessor(TraceBuilderResult traceResult, AbstractBlockBase<?> block) {
AbstractBlockBase<?> bestPred = null;
int bestTraceId = traceResult.getTraceForBlock(block).getId();
for (AbstractBlockBase<?> pred : block.getPredecessors()) {
int predTraceId = traceResult.getTraceForBlock(pred).getId();
if (predTraceId < bestTraceId) {
bestPred = pred;
bestTraceId = predTraceId;
}
}
return bestPred;
}
public static boolean isShadowedRegisterValue(Value value) {
assert value != null;
return value instanceof ShadowedRegisterValue;
}
public static ShadowedRegisterValue asShadowedRegisterValue(Value value) {
assert isShadowedRegisterValue(value);
return (ShadowedRegisterValue) value;
}
public static boolean isTrivialTrace(LIR lir, Trace trace) {
if (trace.size() != 1) {
return false;
}
List<LIRInstruction> instructions = lir.getLIRforBlock(trace.getBlocks()[0]);
if (instructions.size() != 2) {
return false;
}
assert instructions.get(0) instanceof LabelOp : "First instruction not a LabelOp: " + instructions.get(0);
if (((LabelOp) instructions.get(0)).isPhiIn()) {
/*
* Merge blocks are in general not trivial block because variables defined by a PHI
* always need a location. If the outgoing value of the predecessor is a constant we
* need to find an appropriate location (register or stack).
*
* Note that this case should not happen in practice since the trace containing the
* merge block should also contain one of the predecessors. For non-standard trace
* builders (e.g. the single block trace builder) this is not the true, though.
*/
return false;
}
/*
* Now we need to check if the BlockEndOp has no special operand requirements (i.e.
* stack-slot, register). For now we just check for JumpOp because we know that it doesn't.
*/
return instructions.get(1) instanceof JumpOp;
}
}