1 /*
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3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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13  * accompanied this code).
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23 
24 
25 package org.graalvm.compiler.hotspot.meta;
26 
27 import org.graalvm.compiler.core.common.spi.JavaConstantFieldProvider;
28 import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;
29 import org.graalvm.compiler.options.OptionValues;
30 
31 import jdk.vm.ci.hotspot.HotSpotResolvedJavaField;
32 import jdk.vm.ci.meta.MetaAccessProvider;
33 import jdk.vm.ci.meta.ResolvedJavaField;
34 import jdk.vm.ci.meta.ResolvedJavaType;
35 
36 /**
37  * Implements the default constant folding semantics for Java fields in the HotSpot VM.
38  */
39 public class HotSpotConstantFieldProvider extends JavaConstantFieldProvider {
40 
41     private final GraalHotSpotVMConfig config;
42 
HotSpotConstantFieldProvider(GraalHotSpotVMConfig config, MetaAccessProvider metaAccess)43     public HotSpotConstantFieldProvider(GraalHotSpotVMConfig config, MetaAccessProvider metaAccess) {
44         super(metaAccess);
45         this.config = config;
46     }
47 
48     @Override
isStableField(ResolvedJavaField field, ConstantFieldTool<?> tool)49     protected boolean isStableField(ResolvedJavaField field, ConstantFieldTool<?> tool) {
50         if (!config.foldStableValues) {
51             return false;
52         }
53         if (field.isStatic() && !isStaticFieldConstant(field, tool.getOptions())) {
54             return false;
55         }
56 
57         if (((HotSpotResolvedJavaField) field).isStable()) {
58             return true;
59         }
60         return super.isStableField(field, tool);
61     }
62 
63     @Override
isFinalField(ResolvedJavaField field, ConstantFieldTool<?> tool)64     protected boolean isFinalField(ResolvedJavaField field, ConstantFieldTool<?> tool) {
65         if (field.isStatic() && !isStaticFieldConstant(field, tool.getOptions())) {
66             return false;
67         }
68 
69         return super.isFinalField(field, tool);
70     }
71 
72     private static final String SystemClassName = "Ljava/lang/System;";
73 
isStaticFieldConstant(ResolvedJavaField field, @SuppressWarnings(R) OptionValues options)74     protected boolean isStaticFieldConstant(ResolvedJavaField field, @SuppressWarnings("unused") OptionValues options) {
75         ResolvedJavaType declaringClass = field.getDeclaringClass();
76         return declaringClass.isInitialized() && !declaringClass.getName().equals(SystemClassName);
77     }
78 }
79