jminusminus

Class JCompilationUnit

java.lang.Object

jminusminus.JAST

jminusminus.JCompilationUnit

 class JCompilationUnit
extends JAST

The abstract syntax tree (AST) node representing a compilation unit, and so the root of the AST. It keeps track of the name of the source file, its package name, a list of imported types, a list of type (eg class) declarations, and a flag indicating if a semantic error has been detected in analysis or code generation. It also maintains a CompilationUnitContext (built in pre-analysis) for declaring both imported and declared types. The AST is produced by the Parser. Once the AST has been built, three successive methods are invoked: (1) Method preAnalyze() is invoked for making a first pass at type analysis, recursively reaching down to the member headers for declaring types and member interfaces in the environment (contexts). preAnalyze() also creates a partial class file (in memory) for recording member header information, using the partialCodegen() method. (2) Method analyze() is invoked for type-checking field initializations and method bodies, and determining the types of all expressions. A certain amount of tree surgery is also done here. And stack frame offsets are computed for method parameters and local variables. (3) Method codegen() is invoked for generating code for the compilation unit to a class file. For each type declaration, it instantiates a CLEmmiter object (an abstraction of the class file) and then invokes methods on that CLEmitter for generating instructions. At the end of each type declaration, a method is invoked on the CLEmitter which writes the class out to the file system either as .class file or as a .s (SPIM) file. Of course, codegen() makes recursive calls down the tree, to the codegen() methods at each node, for generating the appropriate instructions.

Field Summary

Fields inherited from class jminusminus.JAST

compilationUnit, line

Constructor Summary

Constructors

Constructor and Description
JCompilationUnit(String fileName, int line, TypeName packageName, ArrayList<TypeName> imports, ArrayList<JAST> typeDeclarations) Construct an AST node for a compilation unit given a file name, class directory, line number, package name, list of imports, and type declarations.

Method Summary

Methods

Modifier and Type	Method and Description
JAST	analyze(Context context) Perform semantic analysis on the AST in the specified context.
ArrayList<CLFile>	clFiles() Return the list of CLFile objects corresponding to the type declarations in this compilation unit.
void	codegen(CLEmitter output) Generating code for a compilation unit means generating code for each of the type declarations.
boolean	errorHasOccurred() Has a semantic error occurred up to now?
String	packageName() The package in which this compilation unit is defined.
void	preAnalyze() Construct a context for the compilation unit, initializing it with imported types.
void	reportSemanticError(int line, String message, Object... arguments) Report a semantic error.
void	writeToStdOut(PrettyPrinter p) Write the information pertaining to this AST to STDOUT.

Methods inherited from class jminusminus.JAST

line, partialCodegen

Methods inherited from class java.lang.Object

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

Constructor Detail

JCompilationUnit

public JCompilationUnit(String fileName,
                int line,
                TypeName packageName,
                ArrayList<TypeName> imports,
                ArrayList<JAST> typeDeclarations)

Construct an AST node for a compilation unit given a file name, class directory, line number, package name, list of imports, and type declarations.

Parameters:

fileName - the name of the source file.

line - line in which the compilation unit occurs in the source file.

packageName - package name.

imports - a list of imports.

typeDeclarations - type declarations.

Method Detail

packageName

public String packageName()

The package in which this compilation unit is defined.

Returns:

the package name.

errorHasOccurred

public boolean errorHasOccurred()

Has a semantic error occurred up to now?

Returns:

true or false.

reportSemanticError

public void reportSemanticError(int line,
                       String message,
                       Object... arguments)

Report a semantic error.

Parameters:

line - line in which the error occurred in the source file.

message - message identifying the error.

arguments - related values.

preAnalyze

public void preAnalyze()

Construct a context for the compilation unit, initializing it with imported types. Then pre-analyze the unit's type declarations, adding their types to the context.

analyze

public JAST analyze(Context context)

Perform semantic analysis on the AST in the specified context.

Specified by:

analyze in class JAST

Parameters:

context - context in which names are resolved (ignored here).

Returns:

the analyzed (and possibly rewritten) AST subtree.

codegen

public void codegen(CLEmitter output)

Generating code for a compilation unit means generating code for each of the type declarations.

Specified by:

codegen in class JAST

Parameters:

output - the code emitter (basically an abstraction for producing the .class file).

clFiles

public ArrayList<CLFile> clFiles()

Return the list of CLFile objects corresponding to the type declarations in this compilation unit.

Returns:

list of CLFile objects.

writeToStdOut

public void writeToStdOut(PrettyPrinter p)

Description copied from class: JAST

Write the information pertaining to this AST to STDOUT.

Specified by:

writeToStdOut in class JAST

Parameters:

p - for pretty printing with indentation.