framework/src/main/java/org/checkerframework/common/value/ValueChecker.java

package org.checkerframework.common.value;

import java.util.LinkedHashSet;
import org.checkerframework.common.basetype.BaseTypeChecker;
import org.checkerframework.common.basetype.BaseTypeVisitor;
import org.checkerframework.common.value.util.Range;
import org.checkerframework.framework.source.SupportedOptions;

/**
 * The Constant Value Checker is a constant propagation analysis: for each variable, it determines
 * whether that variable's value can be known at compile time.
 *
 * <p>The Constant Value Checker has no dependencies, but it does trust {@code
 * org.checkerframework.checker.index.qual.Positive} annotations from the Index Checker. This means
 * that if the Value Checker is run on code containing {@code Positive} annotations, then the Index
 * Checker also needs to be run to guarantee soundness.
 *
 * @checker_framework.manual #constant-value-checker Constant Value Checker
 */
@SupportedOptions({
  ValueChecker.REPORT_EVAL_WARNS,
  ValueChecker.IGNORE_RANGE_OVERFLOW,
  ValueChecker.NON_NULL_STRINGS_CONCATENATION
})
public class ValueChecker extends BaseTypeChecker {
  /**
   * Command-line option to warn the user if a @StaticallyExecutable method can't load and run at
   * compile time.
   */
  public static final String REPORT_EVAL_WARNS = "reportEvalWarns";
  /** Command-line option to ignore the possibility of overflow for range annotations. */
  public static final String IGNORE_RANGE_OVERFLOW = "ignoreRangeOverflow";
  /** Command-line option that assumes most expressions in String concatenations can be null. */
  public static final String NON_NULL_STRINGS_CONCATENATION = "nonNullStringsConcatenation";

  @Override
  protected BaseTypeVisitor<?> createSourceVisitor() {
    return new ValueVisitor(this);
  }

  @Override
  protected LinkedHashSet<Class<? extends BaseTypeChecker>> getImmediateSubcheckerClasses() {
    // Don't call super otherwise MethodVal will be added as a subChecker
    // which creates a circular dependency.
    return new LinkedHashSet<>();
  }

  @Override
  public boolean shouldResolveReflection() {
    // Because this checker is a subchecker of MethodVal,
    // reflection can't be resolved.
    return false;
  }

  @Override
  public void typeProcessingOver() {
    // Reset ignore overflow.
    Range.ignoreOverflow = false;
    super.typeProcessingOver();
  }
}