bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/internal/codegen/ssa/exits/If.java

   1 package org.simantics.scl.compiler.internal.codegen.ssa.exits;
   2
   3 import java.util.ArrayList;
   4
   5 import org.objectweb.asm.Label;
   6 import org.simantics.scl.compiler.common.exceptions.InternalCompilerError;
   7 import org.simantics.scl.compiler.constants.BooleanConstant;
   8 import org.simantics.scl.compiler.constants.ComparisonFunction;
   9 import org.simantics.scl.compiler.internal.codegen.continuations.Cont;
  10 import org.simantics.scl.compiler.internal.codegen.continuations.ContRef;
  11 import org.simantics.scl.compiler.internal.codegen.references.BoundVar;
  12 import org.simantics.scl.compiler.internal.codegen.references.Val;
  13 import org.simantics.scl.compiler.internal.codegen.references.ValRef;
  14 import org.simantics.scl.compiler.internal.codegen.ssa.SSABlock;
  15 import org.simantics.scl.compiler.internal.codegen.ssa.SSAExit;
  16 import org.simantics.scl.compiler.internal.codegen.ssa.SSAFunction;
  17 import org.simantics.scl.compiler.internal.codegen.ssa.binders.ValRefBinder;
  18 import org.simantics.scl.compiler.internal.codegen.ssa.statements.LetApply;
  19 import org.simantics.scl.compiler.internal.codegen.utils.CopyContext;
  20 import org.simantics.scl.compiler.internal.codegen.utils.MethodBuilder;
  21 import org.simantics.scl.compiler.internal.codegen.utils.PrintingContext;
  22 import org.simantics.scl.compiler.internal.codegen.utils.SSASimplificationContext;
  23 import org.simantics.scl.compiler.internal.codegen.utils.SSAValidationContext;
  24 import org.simantics.scl.compiler.internal.codegen.utils.ValRefVisitor;
  25 import org.simantics.scl.compiler.types.TVar;
  26 import org.simantics.scl.compiler.types.Type;
  27 import org.simantics.scl.compiler.types.Types;
  28
  29 public class If extends SSAExit implements ValRefBinder {
  30     private ValRef condition;
  31     private ContRef thenTarget;
  32     private ContRef elseTarget;
  33
  34     public If(ValRef condition, ContRef thenTarget, ContRef elseTarget) {
  35         setCondition(condition);
  36         setThenTarget(thenTarget);
  37         setElseTarget(elseTarget);
  38     }
  39
  40     public void setCondition(ValRef condition) {
  41         this.condition = condition;
  42         condition.setParent(this);
  43     }
  44
  45     public void setThenTarget(ContRef thenTarget) {
  46         this.thenTarget = thenTarget;
  47         thenTarget.setParent(this);
  48     }
  49
  50     public void setElseTarget(ContRef elseTarget) {
  51         this.elseTarget = elseTarget;
  52         elseTarget.setParent(this);
  53     }
  54
  55     @Override
  56     public void generateCode(MethodBuilder mb) {
  57         Val binding = condition.getBinding();
  58         simplifyTestCode: if(binding instanceof BoundVar) {
  59             BoundVar boundVar = (BoundVar)binding;
  60             if(!boundVar.generateOnFly)
  61                 break simplifyTestCode;
  62             LetApply apply = (LetApply)boundVar.getParent();
  63             Val function = apply.getFunction().getBinding();
  64             if(!(function instanceof ComparisonFunction))
  65                 break simplifyTestCode;
  66
  67             Val[] ps = ValRef.getBindings(apply.getParameters());
  68             ((ComparisonFunction)function).generateCondition(mb, ps, thenTarget.getBinding(), elseTarget.getBinding());
  69             return;
  70         }
  71         mb.push(condition.getBinding(), Types.BOOLEAN);
  72         Label elseLabel = mb.getLabel(elseTarget.getBinding());
  73         mb.ifZeroComparisonBranch(elseLabel, "==");
  74         mb.jump(thenTarget.getBinding());
  75         mb.ensureExists(elseTarget.getBinding());
  76     }
  77
  78     @Override
  79     public void toString(PrintingContext context) {
  80         context.append("if ");
  81         context.append(condition);
  82         context.append(" then ");
  83         {
  84             Cont thenCont = thenTarget.getBinding();
  85             if(thenCont instanceof SSABlock) {
  86                 SSABlock thenBlock = (SSABlock)thenCont;
  87                 if(thenCont.hasMoreThanOneOccurences()) {
  88                     context.append(thenCont);
  89                     context.addBlock(thenBlock);
  90                     context.append(' ');
  91                 }
  92                 else {
  93                     context.append('\n');
  94                     thenBlock.bodyToString(context);
  95                     context.indentation();
  96                 }
  97             }
  98             else {
  99                 context.append(thenCont);
 100                 context.append(' ');
 101             }
 102         }
 103         context.append("else ");
 104         {
 105             Cont elseCont = elseTarget.getBinding();
 106             if(elseCont instanceof SSABlock) {
 107                 SSABlock elseBlock = (SSABlock)elseCont;
 108                 if(elseCont.hasMoreThanOneOccurences()) {
 109                     context.append(elseCont);
 110                     context.addBlock(elseBlock);
 111                     context.append('\n');
 112                 }
 113                 else {
 114                     context.append('\n');
 115                     elseBlock.bodyToString(context);
 116                 }
 117             }
 118             else {
 119                 context.append(elseCont);
 120                 context.append('\n');
 121             }
 122         }
 123     }
 124
 125     @Override
 126     public void validate(SSAValidationContext context) {
 127         context.validate(condition);
 128         context.validate(elseTarget);
 129         context.validate(thenTarget);
 130         if(condition.getParent() != this)
 131             throw new InternalCompilerError();
 132         if(elseTarget.getParent() != this)
 133             throw new InternalCompilerError();
 134         if(thenTarget.getParent() != this)
 135             throw new InternalCompilerError();
 136         context.assertEquals(this, condition.getType(), Types.BOOLEAN);
 137         context.assertEquals(elseTarget.getBinding().getArity(), 0);
 138         context.assertEquals(thenTarget.getBinding().getArity(), 0);
 139     }
 140
 141     @Override
 142     public void destroy() {
 143         condition.remove();
 144         elseTarget.remove();
 145         thenTarget.remove();
 146     }
 147
 148     @Override
 149     public SSAExit copy(CopyContext context) {
 150         return new If(context.copy(condition),
 151                 context.copy(thenTarget),
 152                 context.copy(elseTarget));
 153     }
 154
 155     @Override
 156     public void replace(TVar[] vars, Type[] replacements) {
 157         condition.replace(vars, replacements);
 158     }
 159
 160     @Override
 161     public void simplify(SSASimplificationContext context) {
 162         Val cond = condition.getBinding();
 163         if(cond instanceof BooleanConstant) {
 164             SSAExit newExit;
 165             if(((BooleanConstant) cond).getValue()) {
 166                 newExit = new Jump(thenTarget);
 167                 elseTarget.remove();
 168             }
 169             else {
 170                 newExit = new Jump(elseTarget);
 171                 thenTarget.remove();
 172             }
 173             condition.remove();
 174             getParent().setExit(newExit);
 175             context.markModified("beta-if");
 176         }
 177         else if(thenTarget.getBinding() == elseTarget.getBinding()) {
 178             elseTarget.remove();
 179             condition.remove();
 180             getParent().setExit(new Jump(thenTarget));
 181             context.markModified("equal-branches-if");
 182         }
 183     }
 184
 185     @Override
 186     public void collectFreeVariables(SSAFunction function,
 187             ArrayList<ValRef> vars) {
 188         condition.collectFreeVariables(function, vars);
 189     }
 190
 191     @Override
 192     public Cont addParametersInFrontOf(ContRef contRef, Val[] newParameters, Val[] oldParameters,
 193             Cont proxy) {
 194         if(proxy == null)
 195             proxy = contRef.getBinding().createProxy(getParent().getParent(), newParameters, oldParameters);
 196         ContRef proxyRef = proxy.createOccurrence();
 197         if(thenTarget == contRef)
 198             setThenTarget(proxyRef);
 199         else
 200             setElseTarget(proxyRef);
 201         return proxy;
 202     }
 203
 204     @Override
 205     public SSABlock[] getSuccessors() {
 206         Cont thenCont = thenTarget.getBinding();
 207         Cont elseCont = elseTarget.getBinding();
 208         if(thenCont instanceof SSABlock) {
 209             if(elseCont instanceof SSABlock)
 210                 return new SSABlock[] {(SSABlock)thenCont, (SSABlock)elseCont};
 211             else
 212                 return new SSABlock[] {(SSABlock)thenCont};
 213         }
 214         else {
 215             if(elseCont instanceof SSABlock)
 216                 return new SSABlock[] {(SSABlock)elseCont};
 217             else
 218                 return SSABlock.EMPTY_ARRAY;
 219         }
 220     }
 221
 222     @Override
 223     public void forValRefs(ValRefVisitor visitor) {
 224         visitor.visit(condition);
 225     }
 226
 227     @Override
 228     public void cleanup() {
 229         condition.remove();
 230     }
 231 }