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(int lineNumber, ValRef condition, ContRef thenTarget, ContRef elseTarget) {
  35         super(lineNumber);
  36         setCondition(condition);
  37         setThenTarget(thenTarget);
  38         setElseTarget(elseTarget);
  39     }
  40
  41     public void setCondition(ValRef condition) {
  42         this.condition = condition;
  43         condition.setParent(this);
  44     }
  45
  46     public void setThenTarget(ContRef thenTarget) {
  47         this.thenTarget = thenTarget;
  48         thenTarget.setParent(this);
  49     }
  50
  51     public void setElseTarget(ContRef elseTarget) {
  52         this.elseTarget = elseTarget;
  53         elseTarget.setParent(this);
  54     }
  55
  56     @Override
  57     public void generateCode(MethodBuilder mb) {
  58         mb.lineNumber(lineNumber);
  59         Val binding = condition.getBinding();
  60         simplifyTestCode: if(binding instanceof BoundVar) {
  61             BoundVar boundVar = (BoundVar)binding;
  62             if(!boundVar.generateOnFly)
  63                 break simplifyTestCode;
  64             LetApply apply = (LetApply)boundVar.getParent();
  65             Val function = apply.getFunction().getBinding();
  66             if(!(function instanceof ComparisonFunction))
  67                 break simplifyTestCode;
  68
  69             Val[] ps = ValRef.getBindings(apply.getParameters());
  70             ((ComparisonFunction)function).generateCondition(mb, ps, thenTarget.getBinding(), elseTarget.getBinding());
  71             return;
  72         }
  73         mb.push(condition.getBinding(), Types.BOOLEAN);
  74         Label elseLabel = mb.getLabel(elseTarget.getBinding());
  75         mb.ifZeroComparisonBranch(elseLabel, "==");
  76         mb.jump(thenTarget.getBinding());
  77         mb.ensureExists(elseTarget.getBinding());
  78     }
  79
  80     @Override
  81     public void toString(PrintingContext context) {
  82         context.append("if ");
  83         context.append(condition);
  84         context.append(" then ");
  85         {
  86             Cont thenCont = thenTarget.getBinding();
  87             if(thenCont instanceof SSABlock) {
  88                 SSABlock thenBlock = (SSABlock)thenCont;
  89                 if(thenCont.hasMoreThanOneOccurences()) {
  90                     context.append(thenCont);
  91                     context.addBlock(thenBlock);
  92                     context.append(' ');
  93                 }
  94                 else {
  95                     context.append('\n');
  96                     thenBlock.bodyToString(context);
  97                     context.indentation();
  98                 }
  99             }
 100             else {
 101                 context.append(thenCont);
 102                 context.append(' ');
 103             }
 104         }
 105         context.append("else ");
 106         {
 107             Cont elseCont = elseTarget.getBinding();
 108             if(elseCont instanceof SSABlock) {
 109                 SSABlock elseBlock = (SSABlock)elseCont;
 110                 if(elseCont.hasMoreThanOneOccurences()) {
 111                     context.append(elseCont);
 112                     context.addBlock(elseBlock);
 113                     context.append('\n');
 114                 }
 115                 else {
 116                     context.append('\n');
 117                     elseBlock.bodyToString(context);
 118                 }
 119             }
 120             else {
 121                 context.append(elseCont);
 122                 context.append('\n');
 123             }
 124         }
 125     }
 126
 127     @Override
 128     public void validate(SSAValidationContext context) {
 129         context.validate(condition);
 130         context.validate(elseTarget);
 131         context.validate(thenTarget);
 132         if(condition.getParent() != this)
 133             throw new InternalCompilerError();
 134         if(elseTarget.getParent() != this)
 135             throw new InternalCompilerError();
 136         if(thenTarget.getParent() != this)
 137             throw new InternalCompilerError();
 138         context.assertEquals(this, condition.getType(), Types.BOOLEAN);
 139         context.assertEquals(elseTarget.getBinding().getArity(), 0);
 140         context.assertEquals(thenTarget.getBinding().getArity(), 0);
 141     }
 142
 143     @Override
 144     public void destroy() {
 145         condition.remove();
 146         elseTarget.remove();
 147         thenTarget.remove();
 148     }
 149
 150     @Override
 151     public SSAExit copy(CopyContext context) {
 152         If copy = new If(lineNumber,
 153                 context.copy(condition),
 154                 context.copy(thenTarget),
 155                 context.copy(elseTarget));
 156         return copy;
 157     }
 158
 159     @Override
 160     public void replace(TVar[] vars, Type[] replacements) {
 161         condition.replace(vars, replacements);
 162     }
 163
 164     @Override
 165     public void simplify(SSASimplificationContext context) {
 166         Val cond = condition.getBinding();
 167         if(cond instanceof BooleanConstant) {
 168             SSAExit newExit;
 169             if(((BooleanConstant) cond).getValue()) {
 170                 newExit = new Jump(lineNumber, thenTarget);
 171                 elseTarget.remove();
 172             }
 173             else {
 174                 newExit = new Jump(lineNumber, elseTarget);
 175                 thenTarget.remove();
 176             }
 177             condition.remove();
 178             getParent().setExit(newExit);
 179             context.markModified("beta-if");
 180         }
 181         else if(thenTarget.getBinding() == elseTarget.getBinding()) {
 182             elseTarget.remove();
 183             condition.remove();
 184             getParent().setExit(new Jump(lineNumber, thenTarget));
 185             context.markModified("equal-branches-if");
 186         }
 187     }
 188
 189     @Override
 190     public void collectFreeVariables(SSAFunction function,
 191             ArrayList<ValRef> vars) {
 192         condition.collectFreeVariables(function, vars);
 193     }
 194
 195     @Override
 196     public Cont addParametersInFrontOf(ContRef contRef, Val[] newParameters, Val[] oldParameters,
 197             Cont proxy) {
 198         if(proxy == null)
 199             proxy = contRef.getBinding().createProxy(getParent().getParent(), newParameters, oldParameters);
 200         ContRef proxyRef = proxy.createOccurrence();
 201         if(thenTarget == contRef)
 202             setThenTarget(proxyRef);
 203         else
 204             setElseTarget(proxyRef);
 205         return proxy;
 206     }
 207
 208     @Override
 209     public SSABlock[] getSuccessors() {
 210         Cont thenCont = thenTarget.getBinding();
 211         Cont elseCont = elseTarget.getBinding();
 212         if(thenCont instanceof SSABlock) {
 213             if(elseCont instanceof SSABlock)
 214                 return new SSABlock[] {(SSABlock)thenCont, (SSABlock)elseCont};
 215             else
 216                 return new SSABlock[] {(SSABlock)thenCont};
 217         }
 218         else {
 219             if(elseCont instanceof SSABlock)
 220                 return new SSABlock[] {(SSABlock)elseCont};
 221             else
 222                 return SSABlock.EMPTY_ARRAY;
 223         }
 224     }
 225
 226     @Override
 227     public void forValRefs(ValRefVisitor visitor) {
 228         visitor.visit(condition);
 229     }
 230
 231     @Override
 232     public void cleanup() {
 233         condition.remove();
 234     }
 235 }