Module program 

Core JVM program representation

JVM Program Model

This module defines the abstract representation (Intermediate Representation) of a JVM program. It serves as the central data structure that links various formats (Class binary, JASM assembly) and tools (Analyzer, Optimizer).

Core Components

• JvmProgram: The top-level structure representing a single JVM class, including its name, superclass, interfaces, fields, methods, and attributes.
• JvmMethod: Represents a method within a class, containing its descriptor, access flags, bytecode instructions, and exception handlers.
• JvmField: Represents a field within a class, including its type, initial value, and attributes.
• JvmInstruction: A comprehensive enum covering all JVM opcodes, using high-level symbolic representations (e.g., using strings for class names instead of constant pool indices).
• JvmConstantPool: A managed constant pool that handles deduplication and indexing automatically during serialization.

Key Features

• Type Safety: Uses Rust’s type system to ensure valid instruction parameters and class structures.
• Symbolic Representation: Instructions use human-readable names and descriptors, which are resolved to constant pool indices only during the final writing phase.
• Attribute Support: Support for standard JVM attributes like Code, LineNumberTable, LocalVariableTable, StackMapTable, etc.

Usage Example

use jvm_assembler::program::{JvmProgram, JvmMethod, JvmInstruction};

// Create a new program (class)
let mut program = JvmProgram::new("com/example/MyClass".into());
program.super_class = Some("java/lang/Object".into());

// Add a method
let mut main_method = JvmMethod::new(
    "main".into(),
    "([Ljava/lang/String;)V".into(),
    vec![
        JvmInstruction::Getstatic("java/lang/System".into(), "out".into(), "Ljava/io/PrintStream;".into()),
        JvmInstruction::LdcString("Hello from IR!".into()),
        JvmInstruction::Invokevirtual("java/io/PrintStream".into(), "println".into(), "(Ljava/lang/String;)V".into()),
        JvmInstruction::Return,
    ]
);
main_method.access_flags = 0x0009; // public static

program.methods.push(main_method);

Re-exports

pub use entities::*;

pub use instructions::*;

pub use legacy::*;

pub use pool::*;

pub use types::*;

Modules

entities

JVM program entity definitions

instructions

JVM instruction definitions

legacy

Legacy compatibility layer

pool

Constant pool management

types

Core JVM types and enumerations