NBasicBlock (j-- (A Non-trivial Subset of Java))

java.lang.Object
- jminusminus.NBasicBlock

```
 class NBasicBlock
extends Object
```
Representation of a block within a control flow graph.

Field Summary

Fields
Modifier and Type	Field and Description
`boolean`	`active` Is this block active?
`int`	`bwdBranches` Number of backward branches to this block.
`NControlFlowGraph`	`cfg` The control flow graph (cfg) that this block belongs to.
`NBasicBlock`	`dom` The dominator of this block.
`int`	`fwdBranches` Number of forward branches to this block.
`ArrayList<Integer>`	`hir` List of high-level (HIR) instructions in this block.
`int`	`id` Unique identifier of ths block.
`boolean`	`isLoopHead` Is this block a loop head?
`boolean`	`isLoopTail` Is this block a loop tail?
`ArrayList<NLIRInstruction>`	`lir` List of low-level (LIR) instructions in this block.
`BitSet`	`liveDef` All virtual registers locally defined within this block.
`BitSet`	`liveIn` All virtual registers live in the block.
`BitSet`	`liveOut` All virtual registers live outside the block.
`BitSet`	`liveUse` All virtual registers used before definition within this block.
`int[]`	`locals` The state array for this block that maps local variable index to the HIR instruction that last affected it.
`int`	`loopDepth` Depth of a loop.
`int`	`loopIndex` Index of a loop.
`ArrayList<NBasicBlock>`	`predecessors` List of predecessor blocks.
`int`	`ref` Ref count of this block.
`ArrayList<NBasicBlock>`	`successors` List of successor blocks.
`ArrayList<NTuple>`	`tuples` List of tuples in this block.
`boolean`	`visited` Has this block been visited?

Constructor Summary

Constructors
Constructor and Description

NBasicBlock(NControlFlowGraph cfg, int id)
Construct a block given its unique identifier.

Constructors
Constructor and Description
`NBasicBlock(NControlFlowGraph cfg, int id)` Construct a block given its unique identifier.

Method Summary

Methods
Modifier and Type	Method and Description
`boolean`	`equals(NBasicBlock other)` Is this block the same as the other block? Two blocks are the same if their ids are the same.
`int`	`getFirstLIRInstId()` The instruction identifier for the first LIR instruction.
`NLIRInstruction`	`getInstruction(int id)` Iterates through the lir array of this block, returning an NLIRInstruction with the specified id.
`int`	`getLastLIRInstId()` The instruction identifier for the last LIR instruction.
`String`	`id()` Return a string identifier of this block.
`boolean`	`idIsFree(int id)` Checks to see if there is an LIRInstruction with this id in the block's lir.
`void`	`insertLIRInst(NLIRInstruction inst)` Inserts an NLIRInstruction to the appropriate place in this block's lir array based on its id -- preserving order by id.
`String`	`toString()` Return a string representation of this block.
`void`	`writeHirToStdOut(PrettyPrinter p)` Write the HIR instructions in this block to STDOUT.
`void`	`writeLirToStdOut(PrettyPrinter p)` Write the LIR instructions in this block to STDOUT.
`void`	`writeTuplesToStdOut(PrettyPrinter p)` Write the tuples in this block to STDOUT.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - cfg
```
public NControlFlowGraph cfg
```
    The control flow graph (cfg) that this block belongs to.
  - id
```
public int id
```
    Unique identifier of ths block.
  - tuples
```
public ArrayList<NTuple> tuples
```
    List of tuples in this block.
  - predecessors
```
public ArrayList<NBasicBlock> predecessors
```
    List of predecessor blocks.
  - successors
```
public ArrayList<NBasicBlock> successors
```
    List of successor blocks.
  - hir
```
public ArrayList<Integer> hir
```
    List of high-level (HIR) instructions in this block.
  - lir
```
public ArrayList<NLIRInstruction> lir
```
    List of low-level (LIR) instructions in this block.
  - locals
```
public int[] locals
```
    The state array for this block that maps local variable index to the HIR instruction that last affected it.
  - visited
```
public boolean visited
```
    Has this block been visited?
  - active
```
public boolean active
```
    Is this block active?
  - isLoopHead
```
public boolean isLoopHead
```
    Is this block a loop head?
  - isLoopTail
```
public boolean isLoopTail
```
    Is this block a loop tail?
  - loopIndex
```
public int loopIndex
```
    Index of a loop.
  - loopDepth
```
public int loopDepth
```
    Depth of a loop.
  - fwdBranches
```
public int fwdBranches
```
    Number of forward branches to this block.
  - bwdBranches
```
public int bwdBranches
```
    Number of backward branches to this block.
  - ref
```
public int ref
```
    Ref count of this block.
  - dom
```
public NBasicBlock dom
```
    The dominator of this block.
  - liveDef
```
public BitSet liveDef
```
    All virtual registers locally defined within this block.
  - liveUse
```
public BitSet liveUse
```
    All virtual registers used before definition within this block.
  - liveIn
```
public BitSet liveIn
```
    All virtual registers live in the block.
  - liveOut
```
public BitSet liveOut
```
    All virtual registers live outside the block.
- Constructor Detail
  - NBasicBlock
```
public NBasicBlock(NControlFlowGraph cfg,
           int id)
```
    Construct a block given its unique identifier.
    
    Parameters:
    cfg - the cfg containing this block.
    id - id of the block.
- Method Detail
  - id
```
public String id()
```
    Return a string identifier of this block.
    
    Returns:
    string identifier of this block.
  - equals
```
public boolean equals(NBasicBlock other)
```
    Is this block the same as the other block? Two blocks are the same if their ids are the same.
    
    Parameters:
    other - the other block.
    
    Returns:
    true or false.
  - toString
```
public String toString()
```
    Return a string representation of this block.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    string representation of this block.
  - writeTuplesToStdOut
```
public void writeTuplesToStdOut(PrettyPrinter p)
```
    Write the tuples in this block to STDOUT.
    
    Parameters:
    p - for pretty printing with indentation.
  - writeHirToStdOut
```
public void writeHirToStdOut(PrettyPrinter p)
```
    Write the HIR instructions in this block to STDOUT.
    
    Parameters:
    p - for pretty printing with indentation.
  - writeLirToStdOut
```
public void writeLirToStdOut(PrettyPrinter p)
```
    Write the LIR instructions in this block to STDOUT.
    
    Parameters:
    p - for pretty printing with indentation.
  - getFirstLIRInstId
```
public int getFirstLIRInstId()
```
    The instruction identifier for the first LIR instruction.
    
    Returns:
    the instruction identifier.
  - getLastLIRInstId
```
public int getLastLIRInstId()
```
    The instruction identifier for the last LIR instruction.
    
    Returns:
    the instruction identifier.
  - getInstruction
```
public NLIRInstruction getInstruction(int id)
```
    Iterates through the lir array of this block, returning an NLIRInstruction with the specified id.
    
    Parameters:
    id - the id to look for.
    
    Returns:
    NLIRInstruction with the specified id, null if none matched.
  - idIsFree
```
public boolean idIsFree(int id)
```
    Checks to see if there is an LIRInstruction with this id in the block's lir.
    
    Returns:
    true or false.
  - insertLIRInst
```
public void insertLIRInst(NLIRInstruction inst)
```
    Inserts an NLIRInstruction to the appropriate place in this block's lir array based on its id -- preserving order by id.
    
    Parameters:
    inst - the NLIRInstruction to be inserted.

Class NBasicBlock

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

cfg

id

tuples

predecessors

successors

hir

lir

locals

visited

active

isLoopHead

isLoopTail

loopIndex

loopDepth

fwdBranches

bwdBranches

ref

dom

liveDef

liveUse

liveIn

liveOut

Constructor Detail

NBasicBlock

Method Detail

id

equals

toString

writeTuplesToStdOut

writeHirToStdOut

writeLirToStdOut

getFirstLIRInstId

getLastLIRInstId

getInstruction

idIsFree

insertLIRInst