--- /dev/null
+package org.simantics.scl.compiler.internal.codegen.ssa.exits;
+
+import java.util.ArrayList;
+
+import org.objectweb.asm.Label;
+import org.simantics.scl.compiler.common.exceptions.InternalCompilerError;
+import org.simantics.scl.compiler.constants.BooleanConstant;
+import org.simantics.scl.compiler.internal.codegen.continuations.BranchRef;
+import org.simantics.scl.compiler.internal.codegen.continuations.Cont;
+import org.simantics.scl.compiler.internal.codegen.continuations.ContRef;
+import org.simantics.scl.compiler.internal.codegen.references.Val;
+import org.simantics.scl.compiler.internal.codegen.references.ValRef;
+import org.simantics.scl.compiler.internal.codegen.ssa.SSABlock;
+import org.simantics.scl.compiler.internal.codegen.ssa.SSAExit;
+import org.simantics.scl.compiler.internal.codegen.ssa.SSAFunction;
+import org.simantics.scl.compiler.internal.codegen.ssa.binders.ValRefBinder;
+import org.simantics.scl.compiler.internal.codegen.utils.CopyContext;
+import org.simantics.scl.compiler.internal.codegen.utils.MethodBuilder;
+import org.simantics.scl.compiler.internal.codegen.utils.PrintingContext;
+import org.simantics.scl.compiler.internal.codegen.utils.SSASimplificationContext;
+import org.simantics.scl.compiler.internal.codegen.utils.SSAValidationContext;
+import org.simantics.scl.compiler.types.TVar;
+import org.simantics.scl.compiler.types.Type;
+import org.simantics.scl.compiler.types.Types;
+
+public class Switch extends SSAExit implements ValRefBinder {
+
+ ValRef scrutinee;
+ BranchRef[] branches;
+
+ public Switch(ValRef scrutinee, BranchRef[] branches) {
+ this.scrutinee = scrutinee;
+ this.branches = branches;
+ scrutinee.setParent(this);
+ for(BranchRef branch : branches)
+ branch.cont.setParent(this);
+ }
+
+ public ValRef getScrutinee() {
+ return scrutinee;
+ }
+
+ public BranchRef[] getBranches() {
+ return branches;
+ }
+
+ @Override
+ public void generateCode(MethodBuilder mb) {
+ for(int i=0;i<branches.length;++i) {
+ BranchRef branch = branches[i];
+ if(branch.constructor == null) {
+ mb.jump(branch.cont);
+ }
+ else if(i < branches.length-1) {
+ Label failure = mb.createLabel();
+ branch.constructor.deconstruct(mb, scrutinee,
+ branch.cont.getBinding(), failure);
+ mb.setLocation(failure);
+ }
+ else {
+ branch.constructor.deconstruct(mb, scrutinee,
+ branch.cont.getBinding(), null);
+ }
+ }
+ }
+
+ @Override
+ public void toString(PrintingContext context) {
+ context.append("switch ");
+ context.append(scrutinee);
+ for(BranchRef branch : branches) {
+ context.append('\n');
+ context.indentation();
+ if(branch.constructor == null)
+ context.append("otherwise");
+ else
+ context.append(branch.constructor.toString());
+ context.append(" -> ");
+ {
+ Cont cont = branch.cont.getBinding();
+ if(cont instanceof SSABlock) {
+ SSABlock block = (SSABlock)cont;
+ if(cont.hasMoreThanOneOccurences()) {
+ context.append(cont);
+ context.append('\n');
+ context.addBlock(block);
+ }
+ else {
+ block.parametersToString(context);
+ context.append('\n');
+ block.bodyToString(context);
+ }
+ }
+ else {
+ context.append(cont);
+ context.append('\n');
+ }
+ }
+ }
+ for(SSABlock block : getSuccessors())
+ context.addBlock(block);
+ }
+
+ @Override
+ public void validate(SSAValidationContext context) {
+ context.validate(scrutinee);
+ if(scrutinee.getParent() != this)
+ throw new InternalCompilerError();
+ for(BranchRef branch : branches) {
+ context.validate(branch.cont);
+ if(branch.cont.getParent() != this)
+ throw new InternalCompilerError();
+ }
+ }
+
+ @Override
+ public void destroy() {
+ scrutinee.remove();
+ for(BranchRef branch : branches)
+ branch.cont.remove();
+ }
+
+ @Override
+ public SSAExit copy(CopyContext context) {
+ return new Switch(context.copy(scrutinee),
+ BranchRef.copy(context, branches));
+ }
+
+ @Override
+ public void replace(TVar[] vars, Type[] replacements) {
+ scrutinee.replace(vars, replacements);
+ }
+
+ @Override
+ public void simplify(SSASimplificationContext context) {
+ if(Types.equals(scrutinee.getType(), Types.BOOLEAN)) {
+ ContRef thenTarget = null;
+ ContRef elseTarget = null;
+ for(BranchRef branch : branches) {
+ boolean used = false;
+ if(branch.constructor == null) {
+ if(thenTarget == null) {
+ thenTarget = branch.cont;
+ used = true;
+ }
+ if(elseTarget == null) {
+ elseTarget = branch.cont;
+ used = true;
+ }
+ }
+ else if(((BooleanConstant)branch.constructor).getValue()) {
+ if(thenTarget == null) {
+ thenTarget = branch.cont;
+ used = true;
+ }
+ }
+ else {
+ if(elseTarget == null) {
+ elseTarget = branch.cont;
+ used = true;
+ }
+ }
+ if(!used)
+ branch.cont.remove();
+ }
+
+ // This may be possible if match compiler has
+ // determined that one of the branches is not possible.
+ if(elseTarget == null)
+ elseTarget = thenTarget;
+ else if(thenTarget == null)
+ thenTarget = elseTarget;
+
+ // Replace switch by jump or if
+ SSAExit newExit;
+ if(thenTarget == elseTarget) {
+ scrutinee.remove();
+ newExit = new Jump(thenTarget);
+ }
+ else {
+ newExit = new If(scrutinee,
+ thenTarget,
+ elseTarget);
+ }
+ getParent().setExit(newExit);
+ context.markModified("switch-to-if");
+ newExit.simplify(context);
+ }
+ else if(branches.length == 1 && branches[0].constructor == null) {
+ scrutinee.remove();
+ getParent().setExit(new Jump(branches[0].cont));
+ }
+ }
+
+ @Override
+ public void collectFreeVariables(SSAFunction function,
+ ArrayList<ValRef> vars) {
+ scrutinee.collectFreeVariables(function, vars);
+ }
+
+ @Override
+ public Cont addParametersInFrontOf(ContRef contRef, Val[] newParameters, Val[] oldParameters,
+ Cont proxy) {
+ if(proxy == null)
+ proxy = contRef.getBinding().createProxy(getParent().getParent(), newParameters, oldParameters);
+ ContRef proxyRef = proxy.createOccurrence();
+ proxyRef.setParent(this);
+ for(BranchRef branch : branches) {
+ if(branch.cont == contRef) {
+ branch.cont = proxyRef;
+ break;
+ }
+ }
+ return proxy;
+ }
+
+ @Override
+ public SSABlock[] getSuccessors() {
+ ArrayList<SSABlock> result = new ArrayList<SSABlock>(branches.length);
+ for(BranchRef branch : branches) {
+ Cont cont = branch.cont.getBinding();
+ if(cont instanceof SSABlock)
+ result.add((SSABlock)cont);
+ }
+ return result.toArray(new SSABlock[result.size()]);
+ }
+}
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