org.plumelib.bcelutil

Class StackVer

java.lang.Object

org.plumelib.bcelutil.StackVer

public final class StackVer
extends Object

This is a slightly modified version of Pass3bVerifier from BCEL. It uses NoConstaintsVisitor as InstConstraintVisitor appears to be quite out of date and incorrectly fails on many valid class files. Hence, StackVer assumes the method is valid and is only interested in the result of the symbolic execution in order to capture the state of the local variables and stack at the start of each byte code instruction.

To see the diffs, you will need a git clone of git@github.com:apache/commons-bcel.git. The particular version StackVer is based on can be retrieved with git show e6dcacb9ca1d:src/main/java/org/apache/bcel/verifier/structurals/Pass3bVerifier.java then run google-java-format on the downloaded file.

The original documentation follows.

This PassVerifier verifies a method of class file according to pass 3, so-called structural verification as described in The Java Virtual Machine Specification, 2nd edition. More detailed information is to be found at the do_verify() method's documentation.

See Also:

do_stack_ver(org.apache.bcel.generic.MethodGen)

Constructor Summary

Constructors

Constructor and Description
StackVer() This class should only be instantiated by a Verifier.

Method Summary

Modifier and Type	Method and Description
void	addMessage(String message) This method adds a (warning) message to the message pool of this PassVerifier.
org.apache.bcel.verifier.VerificationResult	do_stack_ver(org.apache.bcel.generic.MethodGen mg) Pass 3b implements the data flow analysis as described in the Java Virtual Machine Specification, Second Edition.
StackTypes	get_stack_types() Return the types on the stack at each byte code offset.
void	invalidReturnTypeError(org.apache.bcel.generic.Type returnedType, org.apache.bcel.generic.MethodGen m) Throws an exception indicating the returned type is not compatible with the return type of the given method.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

StackVer

public StackVer()

This class should only be instantiated by a Verifier.

See Also:

Verifier

Method Detail

get_stack_types

public StackTypes get_stack_types()

Return the types on the stack at each byte code offset. Only valid after do_stack_ver() is called.

Returns:

the StackTypes object for the method being verified

invalidReturnTypeError

public void invalidReturnTypeError(org.apache.bcel.generic.Type returnedType,
                                   org.apache.bcel.generic.MethodGen m)

Throws an exception indicating the returned type is not compatible with the return type of the given method.

Parameters:

returnedType - the type of the returned expression

m - the method we are processing

Throws:

org.apache.bcel.verifier.exc.StructuralCodeConstraintException - always

Since:

6.0

do_stack_ver

public org.apache.bcel.verifier.VerificationResult do_stack_ver(org.apache.bcel.generic.MethodGen mg)

Pass 3b implements the data flow analysis as described in the Java Virtual Machine Specification, Second Edition. Later versions will use LocalVariablesInfo objects to verify if the verifier-inferred types and the class file's debug information (LocalVariables attributes) match [TODO].

Parameters:

mg - MethodGen for the method to be verified

Returns:

the VerificationResult

See Also:

LocalVariablesInfo, Pass2Verifier.getLocalVariablesInfo(int)

addMessage

public void addMessage(String message)

This method adds a (warning) message to the message pool of this PassVerifier.

Parameters:

message - the String containing the warning message