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org.apache.bcel.verifier.structurals
Class Subroutines
java.lang.Objectorg.apache.bcel.verifier.structurals.Subroutines
- public class Subroutines
- extends java.lang.Object
Instances of this class contain information about the subroutines found in a code array of a method. This implementation considers the top-level (the instructions reachable without a JSR or JSR_W starting off from the first instruction in a code array of a method) being a special subroutine; see getTopLevel() for that. Please note that the definition of subroutines in the Java Virtual Machine Specification, Second Edition is somewhat incomplete. Therefore, JustIce uses an own, more rigid notion. Basically, a subroutine is a piece of code that starts at the target of a JSR of JSR_W instruction and ends at a corresponding RET instruction. Note also that the control flow of a subroutine may be complex and non-linear; and that subroutines may be nested. JustIce also mandates subroutines not to be protected by exception handling code (for the sake of control flow predictability). To understand JustIce's notion of subroutines, please read TODO: refer to the paper.
- Version:
- $Id: Subroutines.java 386056 2006-03-15 11:31:56Z tcurdt $
| Nested Class Summary | |
private class |
Subroutines.SubroutineImpl
This inner class implements the Subroutine interface. |
| Field Summary | |
private static java.lang.Integer |
BLACK
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private static java.lang.Integer |
GRAY
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private java.util.Hashtable |
subroutines
The Hashtable containing the subroutines found. |
Subroutine |
TOPLEVEL
This is referring to a special subroutine, namely the top level. |
private static java.lang.Integer |
WHITE
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| Constructor Summary | |
Subroutines(org.apache.bcel.generic.MethodGen mg)
Constructor. |
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| Method Summary | |
Subroutine |
getSubroutine(org.apache.bcel.generic.InstructionHandle leader)
Returns the Subroutine object associated with the given leader (that is, the first instruction of the subroutine). |
private static org.apache.bcel.generic.InstructionHandle[] |
getSuccessors(org.apache.bcel.generic.InstructionHandle instruction)
A utility method that calculates the successors of a given InstructionHandle in the same subroutine. |
Subroutine |
getTopLevel()
For easy handling, the piece of code that is not a subroutine, the top-level, is also modeled as a Subroutine object. |
private void |
noRecursiveCalls(Subroutine sub,
java.util.Set set)
This (recursive) utility method makes sure that no subroutine is calling a subroutine that uses the same local variable for the RET as themselves (recursively). |
Subroutine |
subroutineOf(org.apache.bcel.generic.InstructionHandle any)
Returns the subroutine object associated with the given instruction. |
java.lang.String |
toString()
Returns a String representation of this object; merely for debugging puposes. |
| Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
| Field Detail |
WHITE
private static final java.lang.Integer WHITE
GRAY
private static final java.lang.Integer GRAY
BLACK
private static final java.lang.Integer BLACK
subroutines
private java.util.Hashtable subroutines
- The Hashtable containing the subroutines found.
Key: InstructionHandle of the leader of the subroutine.
Elements: SubroutineImpl objects.
TOPLEVEL
public final Subroutine TOPLEVEL
- This is referring to a special subroutine, namely the
top level. This is not really a subroutine but we use
it to distinguish between top level instructions and
unreachable instructions.
| Constructor Detail |
Subroutines
public Subroutines(org.apache.bcel.generic.MethodGen mg)
- Constructor.
| Method Detail |
noRecursiveCalls
private void noRecursiveCalls(Subroutine sub, java.util.Set set)
- This (recursive) utility method makes sure that
no subroutine is calling a subroutine
that uses the same local variable for the RET as themselves
(recursively).
This includes that subroutines may not call themselves
recursively, even not through intermediate calls to other
subroutines.
getSubroutine
public Subroutine getSubroutine(org.apache.bcel.generic.InstructionHandle leader)
- Returns the Subroutine object associated with the given
leader (that is, the first instruction of the subroutine).
You must not use this to get the top-level instructions
modeled as a Subroutine object.
subroutineOf
public Subroutine subroutineOf(org.apache.bcel.generic.InstructionHandle any)
- Returns the subroutine object associated with the
given instruction. This is a costly operation, you
should consider using getSubroutine(InstructionHandle).
Returns 'null' if the given InstructionHandle lies
in so-called 'dead code', i.e. code that can never
be executed.
getTopLevel
public Subroutine getTopLevel()
- For easy handling, the piece of code that is not a
subroutine, the top-level, is also modeled as a Subroutine
object.
It is a special Subroutine object where you must not invoke
getEnteringJsrInstructions() or getLeavingRET().
getSuccessors
private static org.apache.bcel.generic.InstructionHandle[] getSuccessors(org.apache.bcel.generic.InstructionHandle instruction)
- A utility method that calculates the successors of a given InstructionHandle
in the same subroutine. That means, a RET does not have any successors
as defined here. A JsrInstruction has its physical successor as its successor
(opposed to its target) as defined here.
toString
public java.lang.String toString()
- Returns a String representation of this object; merely for debugging puposes.
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SUMMARY: JAVADOC | SOURCE | DOWNLOAD | NESTED | FIELD | CONSTR | METHOD |
DETAIL: FIELD | CONSTR | METHOD | ||||||||