Package EDU.purdue.cs.bloat.cfg

Class Block

java.lang.Object

EDU.purdue.cs.bloat.util.GraphNode

EDU.purdue.cs.bloat.cfg.Block

public class Block
extends GraphNode

Block represents a basic block of code used in control flow graphs. A basic block is always entered at its beginning and exits at its end. That is, its first statement is a label and its last statement is a jump. There are no other labels or jumps in between.

Each Block knows its parent block and its children in the dominator and postdominator trees. It also knows which blocks are in its dominance frontier and its postdominance frontier.

See Also:

FlowGraph, DominatorTree, DominanceFrontier

Field Summary

Fields

Modifier and Type	Field	Description
static int	IRREDUCIBLE
static int	NON_HEADER
static int	REDUCIBLE

Fields inherited from class EDU.purdue.cs.bloat.util.GraphNode

postIndex, preds, preIndex, succs

Method Summary

Modifier and Type	Method	Description
boolean	dominates(Block block)	Returns whether or this Block dominates another given Block.
FlowGraph	graph()	Returns the CFG containing the block.
Block	header()
Label	label()	Returns the label associated with this block.
boolean	postdominates(Block block)	Determines whether or not this block postdominates a given block.
void	setHeader(Block header)
void	setTree(Tree tree)	Sets the expression tree for this block.
StackOptimizer	stackOptimizer()	Returns the stack optimizer for this block.
java.lang.String	toString()	Returns a string representation of this block.
Tree	tree()	Returns the expression tree for this block.
void	visit(TreeVisitor visitor)
void	visitChildren(TreeVisitor visitor)	Visits the expression tree contained in this block.

Methods inherited from class EDU.purdue.cs.bloat.util.GraphNode

preds, succs

Methods inherited from class java.lang.Object

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

Field Detail

NON_HEADER

public static final int NON_HEADER

See Also:

Constant Field Values

IRREDUCIBLE

public static final int IRREDUCIBLE

See Also:

Constant Field Values

REDUCIBLE

public static final int REDUCIBLE

See Also:

Constant Field Values

Method Detail

stackOptimizer

public StackOptimizer stackOptimizer()

Returns the stack optimizer for this block.

Returns:

The stack optimizer.

tree

public Tree tree()

Returns the expression tree for this block.

Returns:

The tree.

setTree

public void setTree(Tree tree)

Sets the expression tree for this block.

graph

public FlowGraph graph()

Returns the CFG containing the block.

Returns:

The CFG.

label

public Label label()

Returns the label associated with this block.

visitChildren

public void visitChildren(TreeVisitor visitor)

Visits the expression tree contained in this block.

visit

public void visit(TreeVisitor visitor)

setHeader

public void setHeader(Block header)

header

public Block header()

toString

public java.lang.String toString()

Returns a string representation of this block.

Overrides:

toString in class java.lang.Object

dominates

public boolean dominates(Block block)

Returns whether or this Block dominates another given Block. A node X dominates a node Y when every path from the first node in the CFG (Enter) to Y must pass through X.

postdominates

public boolean postdominates(Block block)

Determines whether or not this block postdominates a given block. A block X is said to postdominate a block Y when every path from Y to the last node in the CFG (Exit) passes through X. This relationship can be thought of as the reverse of dominance. That is, X dominates Y in the reverse CFG.

See Also:

DominatorTree