Merged changes from feature/scl to master.

[simantics/platform.git] / bundles / org.simantics.scl.compiler / src / org / simantics / scl / compiler / constants / singletons / NullCheck.java

diff --git a/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/constants/singletons/NullCheck.java b/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/constants/singletons/NullCheck.java
new file mode 100644 (file)
index 0000000..3089a18
--- /dev/null
+++ b/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/constants/singletons/NullCheck.java
@@ -0,0 +1,49 @@
+package org.simantics.scl.compiler.constants.singletons;\r
+\r
+import org.objectweb.asm.Label;\r
+import org.simantics.scl.compiler.constants.ComparisonFunction;\r
+import org.simantics.scl.compiler.constants.FunctionValue;\r
+import org.simantics.scl.compiler.internal.codegen.continuations.Cont;\r
+import org.simantics.scl.compiler.internal.codegen.references.Val;\r
+import org.simantics.scl.compiler.internal.codegen.utils.MethodBuilder;\r
+import org.simantics.scl.compiler.types.TVar;\r
+import org.simantics.scl.compiler.types.Type;\r
+import org.simantics.scl.compiler.types.Types;\r
+import org.simantics.scl.compiler.types.kinds.Kinds;\r
+\r
+public class NullCheck extends FunctionValue implements ComparisonFunction {\r
+    private static final TVar A = Types.var(Kinds.STAR);\r
+    public static final NullCheck INSTANCE = \r
+            new NullCheck();\r
+    \r
+    private NullCheck() {\r
+        super(new TVar[] {A}, Types.NO_EFFECTS, Types.BOOLEAN, A);\r
+    }\r
+        \r
+    @Override\r
+    public Type applyExact(MethodBuilder mb, Val[] parameters) {\r
+        parameters[0].push(mb);\r
+        Label join = mb.createLabel();\r
+        Label isNull = mb.createLabel();\r
+        mb.ifNullBranch(isNull, true);\r
+        mb.loadConstant(false);\r
+        mb.branch(join);\r
+        mb.setLocation(isNull);\r
+        mb.loadConstant(true);\r
+        mb.setLocation(join);\r
+        return getReturnType();\r
+    }\r
+    \r
+    @Override\r
+    public void generateCondition(MethodBuilder mb, Val[] parameters, Cont then_, Cont else_) {\r
+        parameters[0].push(mb);\r
+        mb.ifNullBranch(mb.getLabel(then_), true);\r
+        mb.jump(else_);\r
+        mb.ensureExists(then_);\r
+    }\r
+\r
+    @Override\r
+    public String toString() {\r
+         return "nullCheck";\r
+    }\r
+}\r