Class Util

java.lang.Object

com.ibm.wala.cfg.Util

public class Util
extends Object

Convenience methods for navigating a ControlFlowGraph.

Constructor Summary

Constructors

Constructor	Description
Util()

Method Summary

Modifier and Type	Method	Description
static boolean	endsWithConditionalBranch(ControlFlowGraph<? extends SSAInstruction,?> G, IBasicBlock<?> b)	Does basic block b end with a conditional branch instruction?
static boolean	endsWithSwitch(ControlFlowGraph<? extends SSAInstruction,?> G, IBasicBlock<?> b)	Does basic block b end with a switch instruction?
static <I, T extends IBasicBlock<I>> T	getFallThruBlock(ControlFlowGraph<I,T> G, T b)	Given that b falls through to the next basic block, what basic block does it fall through to?
static SSAInstruction	getLastInstruction(ControlFlowGraph<? extends SSAInstruction,?> cfg, IBasicBlock<?> b)
static <I extends SSAInstruction, T extends IBasicBlock<I>> T	getNotTakenSuccessor(ControlFlowGraph<I,T> G, T b)	Given that b ends with a conditional branch, return the basic block to which control transfers if the branch is not taken.
static <I extends SSAInstruction, T extends IBasicBlock<I>> int	getSwitchLabel(ControlFlowGraph<I,T> G, T b, T s)	When a switch statement at the end of block b transfers control to block s, which case was taken? TODO: Is this correct? Can't we have multiple cases that apply? Check on this.
static <I extends SSAInstruction, T extends IBasicBlock<I>> T	getTakenSuccessor(ControlFlowGraph<I,T> G, T b)	Given that b ends with a conditional branch, return the basic block to which control transfers if the branch is taken.
static <I extends SSAInstruction, T extends IBasicBlock<I>> boolean	isSwitchDefault(ControlFlowGraph<I,T> G, T b, T s)	Is block s the default case for the switch instruction which is the last instruction of block b?
static <I extends SSAInstruction, T extends IBasicBlock<I>> T	resolveBranch(ControlFlowGraph<I,T> G, T bb, int c1, int c2)	To which IBasicBlock does control flow from basic block bb, which ends in a conditional branch, when the conditional branch operands evaluate to the constants c1 and c2, respectively.
static <I extends SSAInstruction, T extends IBasicBlock<I>> T	resolveSwitch(ControlFlowGraph<I,T> G, T b, int c)	When the tested value of the switch statement in b has value c, which basic block does control transfer to.
static <I, T extends IBasicBlock<I>> int	whichPred(ControlFlowGraph<I,T> cfg, T a, T b)	Given that a is a predecessor of b in the cfg ..

Methods inherited from class java.lang.Object

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

Constructor Details

Util

public Util()

Method Details

getLastInstruction

public static SSAInstruction getLastInstruction(ControlFlowGraph<? extends SSAInstruction,?> cfg,
 IBasicBlock<?> b)

Returns:

the last instruction in basic block b, as stored in the instruction array for cfg

endsWithConditionalBranch

public static boolean endsWithConditionalBranch(ControlFlowGraph<? extends SSAInstruction,?> G,
 IBasicBlock<?> b)

Does basic block b end with a conditional branch instruction?

endsWithSwitch

public static boolean endsWithSwitch(ControlFlowGraph<? extends SSAInstruction,?> G,
 IBasicBlock<?> b)

Does basic block b end with a switch instruction?

getFallThruBlock

public static <I,
T extends IBasicBlock<I>> T getFallThruBlock(ControlFlowGraph<I,T> G,
 T b)

Given that b falls through to the next basic block, what basic block does it fall through to?

getNotTakenSuccessor

public static <I extends SSAInstruction,
T extends IBasicBlock<I>>
T getNotTakenSuccessor(ControlFlowGraph<I,T> G,
 T b)

Given that b ends with a conditional branch, return the basic block to which control transfers if the branch is not taken.

getTakenSuccessor

public static <I extends SSAInstruction,
T extends IBasicBlock<I>>
T getTakenSuccessor(ControlFlowGraph<I,T> G,
 T b)

Given that b ends with a conditional branch, return the basic block to which control transfers if the branch is taken.

resolveSwitch

public static <I extends SSAInstruction,
T extends IBasicBlock<I>>
T resolveSwitch(ControlFlowGraph<I,T> G,
 T b,
 int c)

When the tested value of the switch statement in b has value c, which basic block does control transfer to.

isSwitchDefault

public static <I extends SSAInstruction,
T extends IBasicBlock<I>>
boolean isSwitchDefault(ControlFlowGraph<I,T> G,
 T b,
 T s)

Is block s the default case for the switch instruction which is the last instruction of block b?

getSwitchLabel

public static <I extends SSAInstruction,
T extends IBasicBlock<I>>
int getSwitchLabel(ControlFlowGraph<I,T> G,
 T b,
 T s)

When a switch statement at the end of block b transfers control to block s, which case was taken? TODO: Is this correct? Can't we have multiple cases that apply? Check on this.

resolveBranch

public static <I extends SSAInstruction,
T extends IBasicBlock<I>>
T resolveBranch(ControlFlowGraph<I,T> G,
 T bb,
 int c1,
 int c2)

To which IBasicBlock does control flow from basic block bb, which ends in a conditional branch, when the conditional branch operands evaluate to the constants c1 and c2, respectively.

Callers must resolve the constant values from the SymbolTable before calling this method. These integers are not value numbers;

whichPred

public static <I,
T extends IBasicBlock<I>> int whichPred(ControlFlowGraph<I,T> cfg,
 T a,
 T b)

Given that a is a predecessor of b in the cfg ..

When we enumerate the predecessors of b in order, which is the first index in this order in which a appears? Note that this order corresponds to the order of operands in a phi instruction.