hlt.language.design.kernel

Class Compiler

java.lang.Object

hlt.language.design.kernel.Compiler

public class Compiler
extends java.lang.Object

This is the class defining a compiler object. Such an object serves as the common compilation context shared by an Expression and the subexpressions comprising it. Each type of expression representing a syntactic construct of the kernel language defines a compile(Compiler) method that specifies the way the construct is to be compiled in the context of a given compiler. Such a compiler object consists of attributes and methods for generating straight-line code which consists of the sequence of Instructions corresponding to a top-level expression and its subexpressions. Upon completion of the compilation of a top-level expression, a resulting code array is extracted from the sequence of instructions, which may then be executed in the context of a Runtime object, or, in the case of a Definition, be saved in the code array in the Definition's _codeEntry field - a DefinedEntry object encapsulating its code entry point (which may then be used to access the defined symbol's code for execution).

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	LCO_IS_EFFECTIVE When this flag is set to true, last call optimization is made effective.

Constructor Summary

Constructors

Constructor and Description
Compiler() Creates and returns a new Compiler.

Method Summary

Methods

Modifier and Type	Method and Description
Instruction[]	code() Returns the extracted code array of this compiler's latest complete compilation.
DefinedEntry	codeEntry() When compiling a definition, this returns the DefinedEntry of the symbol being defined; null otherwise.
void	compile(Expression exp) Compiles the specified expression in the context of this compiler.
Instruction	generate(Instruction inst)
Instruction	generate(PushScope pushScope, Expression body)
void	generateStackPop(byte sort)
void	generateUnwrapper(byte sort)
void	generateWrapper(byte sort)
void	inline(Instruction[] code)
boolean	isCompilingDefinition() Return true iff this is compiling a definition.
boolean	isShowingCode()
Instruction	lastInstruction()
int	nextCodeAddress() Returns the next available index in _codeList to use as the address of the next instruction.
void	setCodeEntry(DefinedEntry entry) Sets the _codeEntry of this compiler to the specified DefinedEntry.
void	showCode()
int	targetAddress() Returns the next available index in _codeList marking as a target address.
void	toggleShowCode()

Methods inherited from class java.lang.Object

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

Field Detail

LCO_IS_EFFECTIVE

public static boolean LCO_IS_EFFECTIVE

When this flag is set to true, last call optimization is made effective.

Constructor Detail

Compiler

public Compiler()

Creates and returns a new Compiler.

Method Detail

code

public final Instruction[] code()

Returns the extracted code array of this compiler's latest complete compilation.

nextCodeAddress

public final int nextCodeAddress()

Returns the next available index in _codeList to use as the address of the next instruction.

targetAddress

public final int targetAddress()

Returns the next available index in _codeList marking as a target address.

setCodeEntry

public final void setCodeEntry(DefinedEntry entry)

Sets the _codeEntry of this compiler to the specified DefinedEntry. This is called by the compile method of a Definition.

codeEntry

public final DefinedEntry codeEntry()

When compiling a definition, this returns the DefinedEntry of the symbol being defined; null otherwise.

isCompilingDefinition

public final boolean isCompilingDefinition()

Return true iff this is compiling a definition.

compile

public final void compile(Expression exp)

Compiles the specified expression in the context of this compiler. This method is (must be, in fact) the topmost entry point when compiling a top-level (e.g., non-nested) expression as it unnests all inner scopes into straightline code (which is what the _backpatch method does) and manages code dependencies for incremental compiling of forward definitions (which is what the releaseCodeEntry method does).

lastInstruction

public final Instruction lastInstruction()

toggleShowCode

public final void toggleShowCode()

isShowingCode

public final boolean isShowingCode()

showCode

public final void showCode()

generate

public final Instruction generate(Instruction inst)

generate

public final Instruction generate(PushScope pushScope,
                   Expression body)

inline

public final void inline(Instruction[] code)

generateStackPop

public final void generateStackPop(byte sort)

generateWrapper

public final void generateWrapper(byte sort)

generateUnwrapper

public final void generateUnwrapper(byte sort)