edu.jmu.decaf

Class ILOCGenerator

java.lang.Object

edu.jmu.decaf.DefaultASTVisitor

edu.jmu.decaf.ILOCGenerator

All Implemented Interfaces:

ASTVisitor

Direct Known Subclasses:

MyILOCGenerator

public abstract class ILOCGenerator
extends DefaultASTVisitor

AST post-visitor; converts a Decaf program in AST IR to ILOC IR by walking the tree and recursively emitting sequential IR. Dependencies: BuildSymbolTables and AllocateSymbols

Constructor Summary

Constructors

Constructor and Description
ILOCGenerator()

Method Summary

Modifier and Type	Method and Description
void	addComment(ASTNode node, String text) Add a comment to the most recently-emitted ILOC instruction.
ILOCOperand	base(ASTNode dest, Symbol variable) Fills a register with the base address of a variable.
void	copyCode(ASTNode dest, ASTNode src) Copy the ILOC code from one AST node into another.
void	emit(ASTNode node, ILOCInstruction.Form form) Generate a new ILOC instruction and add it to the code for an AST node.
void	emit(ASTNode node, ILOCInstruction.Form form, ILOCOperand op) Generate a new ILOC instruction and add it to the code for an AST node.
void	emit(ASTNode node, ILOCInstruction.Form form, ILOCOperand op1, ILOCOperand op2) Generate a new ILOC instruction and add it to the code for an AST node.
void	emit(ASTNode node, ILOCInstruction.Form form, ILOCOperand op1, ILOCOperand op2, ILOCOperand op3) Generate a new ILOC instruction and add it to the code for an AST node.
void	emit(ASTNode node, ILOCInstruction insn) Generate a new ILOC instruction and add it to the code for an AST node.
ILOCOperand	emitLoad(ASTLocation dest) Emits a right-hand-side load for a given location.
void	emitStore(ASTAssignment dest, ILOCOperand srcReg) Emits a store for a given assignment.
List<ILOCInstruction>	getCode(ASTNode node) Returns the ILOC code associated with an AST node (via the "code" attribute).
ILOCProgram	getProgram() Returns the generated ILOC program.
ILOCOperand	getTempReg(ASTNode node) Returns the temporary ILOC virtual register associated with the result of evaluating a node in the AST.
ILOCOperand	indexedOffset(ASTNode dest, Symbol variable, ILOCOperand indexReg) Calculates the offset of an indexed variable reference and returns the adjusted offset in an ILOCOperand.
ILOCOperand	offset(Symbol variable) Calculates the offset of a scalar variable reference and returns the adjusted offset in an ILOCOperand.
void	postVisit(ASTProgram node) Finalize ILOC program.
void	setTempReg(ASTNode node, ILOCOperand reg) Sets the temporary ILOC virtual register associated with the result of evaluating a node in the AST.

Methods inherited from class edu.jmu.decaf.DefaultASTVisitor

defaultInVisit, defaultPostVisit, defaultPreVisit, inVisit, postVisit, postVisit, postVisit, postVisit, postVisit, postVisit, postVisit, postVisit, postVisit, postVisit, postVisit, postVisit, postVisit, postVisit, postVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit

Methods inherited from class java.lang.Object

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

Constructor Detail

ILOCGenerator

public ILOCGenerator()

Method Detail

getProgram

public ILOCProgram getProgram()

Returns the generated ILOC program.

Returns:

Generated ILOC program

postVisit

public void postVisit(ASTProgram node)

Finalize ILOC program. Copy info from AST regarding static data region, and create ILOCFunction objects with info from the AST, including the sizes of the function stack frames and the generated instructions.

Specified by:

postVisit in interface ASTVisitor

Overrides:

postVisit in class DefaultASTVisitor

getCode

public List<ILOCInstruction> getCode(ASTNode node)

Returns the ILOC code associated with an AST node (via the "code" attribute).

Parameters:

node - AST node

Returns:

List of ILOC instructions (by reference)

emit

public void emit(ASTNode node,
                 ILOCInstruction insn)

Generate a new ILOC instruction and add it to the code for an AST node. General form.

Parameters:

node - Destination AST node

insn - ILOC instruction to add

emit

public void emit(ASTNode node,
                 ILOCInstruction.Form form)

Generate a new ILOC instruction and add it to the code for an AST node. Zero-operand shortcut form.

Parameters:

node - Destination AST node

form - ILOC instruction form (icode) to add

emit

public void emit(ASTNode node,
                 ILOCInstruction.Form form,
                 ILOCOperand op)

Generate a new ILOC instruction and add it to the code for an AST node. One-operand shortcut form.

Parameters:

node - Destination AST node

form - ILOC instruction form (icode) to add

op - ILOC instruction operand

emit

public void emit(ASTNode node,
                 ILOCInstruction.Form form,
                 ILOCOperand op1,
                 ILOCOperand op2)

Generate a new ILOC instruction and add it to the code for an AST node. Two-operand shortcut form.

Parameters:

node - Destination AST node

form - ILOC instruction form (icode) to add

op1 - First ILOC instruction operand

op2 - Second ILOC instruction operand

emit

public void emit(ASTNode node,
                 ILOCInstruction.Form form,
                 ILOCOperand op1,
                 ILOCOperand op2,
                 ILOCOperand op3)

Generate a new ILOC instruction and add it to the code for an AST node. Three-operand shortcut form.

Parameters:

node - Destination AST node

form - ILOC instruction form (icode) to add

op1 - First ILOC instruction operand

op2 - Second ILOC instruction operand

op3 - Third ILOC instruction operand

copyCode

public void copyCode(ASTNode dest,
                     ASTNode src)

Copy the ILOC code from one AST node into another. Appends the code from the source to the end of the code in the destination.

Parameters:

dest - Destination AST node

src - Source AST node

setTempReg

public void setTempReg(ASTNode node,
                       ILOCOperand reg)

Sets the temporary ILOC virtual register associated with the result of evaluating a node in the AST.

Parameters:

node - AST node

reg - ILOC virtual temporary register

getTempReg

public ILOCOperand getTempReg(ASTNode node)

Returns the temporary ILOC virtual register associated with the result of evaluating a node in the AST.

Parameters:

node - AST node

Returns:

ILOC virtual temporary register

base

public ILOCOperand base(ASTNode dest,
                        Symbol variable)

Fills a register with the base address of a variable.

Parameters:

dest - Destination AST Node

variable - Desired variable

Returns:

Virtual register that contains the base address

offset

public ILOCOperand offset(Symbol variable)

Calculates the offset of a scalar variable reference and returns the adjusted offset in an ILOCOperand.

Parameters:

variable - Desired variable

Returns:

Integer constant operand

indexedOffset

public ILOCOperand indexedOffset(ASTNode dest,
                                 Symbol variable,
                                 ILOCOperand indexReg)

Calculates the offset of an indexed variable reference and returns the adjusted offset in an ILOCOperand.

Parameters:

dest - Destination AST Node

variable - Desired variable

indexReg - Register with the evaluated index

Returns:

Virtual register reference containing indexed location offset

emitLoad

public ILOCOperand emitLoad(ASTLocation dest)

Emits a right-hand-side load for a given location.

Parameters:

dest - Destination AST node

Returns:

Virtual register reference containing the loaded value

emitStore

public void emitStore(ASTAssignment dest,
                      ILOCOperand srcReg)

Emits a store for a given assignment.

Parameters:

dest - Destination AST node

srcReg - Source register

addComment

public void addComment(ASTNode node,
                       String text)

Add a comment to the most recently-emitted ILOC instruction.

Parameters:

node - AST node to which the the comment should be added

text - Comment text