edu.umd.cs.findbugs.ba
Class BetterCFGBuilder2

java.lang.Object
  edu.umd.cs.findbugs.ba.BetterCFGBuilder2

All Implemented Interfaces:

CFGBuilder, Debug, EdgeTypes

public class BetterCFGBuilder2
extends java.lang.Object
implements CFGBuilder, EdgeTypes, Debug

A CFGBuilder that really tries to construct accurate control flow graphs. The CFGs it creates have accurate exception edges, and have accurately inlined JSR subroutines.

Author:

David Hovemeyer

See Also:

CFG

Nested Class Summary

private static class	BetterCFGBuilder2.Context Inlining context.
private static class	BetterCFGBuilder2.EscapeTarget A placeholder for a control edge that escapes its subroutine to return control back to an outer (calling) subroutine.
private class	BetterCFGBuilder2.Subroutine JSR subroutine.
private static class	BetterCFGBuilder2.WorkListItem A work list item for creating the CFG for a subroutine.

Field Summary

private CFG	cfg
private org.apache.bcel.generic.ConstantPoolGen	cpg
private static boolean	DEBUG
private static java.util.LinkedList<BetterCFGBuilder2.EscapeTarget>	emptyEscapeTargetList
private ExceptionHandlerMap	exceptionHandlerMap
private java.util.IdentityHashMap<org.apache.bcel.generic.InstructionHandle,BetterCFGBuilder2.Subroutine>	jsrSubroutineMap
private org.apache.bcel.generic.MethodGen	methodGen
private static boolean	NO_LOAD_CONSTANT_EXCEPTIONS
private static boolean	NO_STATIC_FIELD_EXCEPTIONS
private java.util.LinkedList<BetterCFGBuilder2.Subroutine>	subroutineWorkList
private BetterCFGBuilder2.Subroutine	topLevelSubroutine
private java.util.BitSet	usedInstructionSet

Fields inherited from interface edu.umd.cs.findbugs.ba.EdgeTypes

BACKEDGE_SOURCE_EDGE, BACKEDGE_TARGET_EDGE, CHECKED_EXCEPTIONS_FLAG, EXIT_EDGE, EXPLICIT_EXCEPTIONS_FLAG, FALL_THROUGH_EDGE, GOTO_EDGE, HANDLED_EXCEPTION_EDGE, IFCMP_EDGE, JSR_EDGE, RET_EDGE, RETURN_EDGE, START_EDGE, SWITCH_DEFAULT_EDGE, SWITCH_EDGE, UNHANDLED_EXCEPTION_EDGE, UNKNOWN_EDGE

Fields inherited from interface edu.umd.cs.findbugs.ba.Debug

CHECK_ASSERTIONS, VERIFY_INTEGRITY

Constructor Summary

BetterCFGBuilder2(org.apache.bcel.generic.MethodGen methodGen)
Constructor.

Method Summary

void	build() Build the CFG.
private void	build(BetterCFGBuilder2.Subroutine subroutine) Build a subroutine.
CFG	getCFG() Get the CFG built by this object.
private void	handleExceptions(BetterCFGBuilder2.Subroutine subroutine, org.apache.bcel.generic.InstructionHandle pei, BasicBlock etb) Add exception edges for given instruction.
void	inline(BetterCFGBuilder2.Context context) Inline a subroutine into a calling context.
private CFG	inlineAll() Inline all JSR subroutines into the top-level subroutine.
private static boolean	isMerge(org.apache.bcel.generic.InstructionHandle handle) Determine whether or not the given instruction is a control flow merge.
private boolean	isPEI(org.apache.bcel.generic.InstructionHandle handle) Return whether or not the given instruction can throw exceptions.
static void	main(java.lang.String[] argv) Test driver.

Methods inherited from class java.lang.Object

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

Field Detail

DEBUG

private static final boolean DEBUG

NO_STATIC_FIELD_EXCEPTIONS

private static final boolean NO_STATIC_FIELD_EXCEPTIONS

NO_LOAD_CONSTANT_EXCEPTIONS

private static final boolean NO_LOAD_CONSTANT_EXCEPTIONS

emptyEscapeTargetList

private static final java.util.LinkedList<BetterCFGBuilder2.EscapeTarget> emptyEscapeTargetList

methodGen

private org.apache.bcel.generic.MethodGen methodGen

cpg

private org.apache.bcel.generic.ConstantPoolGen cpg

exceptionHandlerMap

private ExceptionHandlerMap exceptionHandlerMap

usedInstructionSet

private java.util.BitSet usedInstructionSet

subroutineWorkList

private java.util.LinkedList<BetterCFGBuilder2.Subroutine> subroutineWorkList

jsrSubroutineMap

private java.util.IdentityHashMap<org.apache.bcel.generic.InstructionHandle,BetterCFGBuilder2.Subroutine> jsrSubroutineMap

topLevelSubroutine

private BetterCFGBuilder2.Subroutine topLevelSubroutine

cfg

private CFG cfg

Constructor Detail

BetterCFGBuilder2

public BetterCFGBuilder2(org.apache.bcel.generic.MethodGen methodGen)

Constructor.

Parameters:

methodGen - the method to build a CFG for

Method Detail

build

public void build()
           throws CFGBuilderException

Description copied from interface: CFGBuilder

Build the CFG.

Specified by:

build in interface CFGBuilder

Throws:

CFGBuilderException

getCFG

public CFG getCFG()

Description copied from interface: CFGBuilder

Get the CFG built by this object. Assumes that the build() method has already been called.

Specified by:

getCFG in interface CFGBuilder

Returns:

the CFG

build

private void build(BetterCFGBuilder2.Subroutine subroutine)
            throws CFGBuilderException

Build a subroutine. We iteratively add basic blocks to the subroutine until there are no more blocks reachable from the calling context. As JSR instructions are encountered, new Subroutines are added to the subroutine work list.

Parameters:

subroutine - the subroutine

Throws:

CFGBuilderException

handleExceptions

private void handleExceptions(BetterCFGBuilder2.Subroutine subroutine,
                              org.apache.bcel.generic.InstructionHandle pei,
                              BasicBlock etb)

Add exception edges for given instruction.

Parameters:

subroutine - the subroutine containing the instruction

pei - the instruction which throws an exception

etb - the exception thrower block (ETB) for the instruction

isPEI

private boolean isPEI(org.apache.bcel.generic.InstructionHandle handle)

Return whether or not the given instruction can throw exceptions.

Parameters:

handle - the instruction

Returns:

true if the instruction can throw an exception, false otherwise

isMerge

private static boolean isMerge(org.apache.bcel.generic.InstructionHandle handle)

Determine whether or not the given instruction is a control flow merge.

Parameters:

handle - the instruction

Returns:

true if the instruction is a control merge, false otherwise

inlineAll

private CFG inlineAll()
               throws CFGBuilderException

Inline all JSR subroutines into the top-level subroutine. This produces a complete CFG for the entire method, in which all JSR subroutines are inlined.

Returns:

the CFG for the method

Throws:

CFGBuilderException

inline

public void inline(BetterCFGBuilder2.Context context)
            throws CFGBuilderException

Inline a subroutine into a calling context.

Parameters:

context - the Context

Throws:

CFGBuilderException

main

public static void main(java.lang.String[] argv)
                 throws java.lang.Exception

Test driver.

Throws:

java.lang.Exception