Source-to-source compiler - AbsoluteAstronomy.com

A source-to-source compiler is a type of compiler

Compiler

A compiler is a computer program that transforms source code written in a programming language into another computer language...

that takes a high level programming language as its input and outputs a high level language. For example, an automatic parallelizing compiler will frequently take in a high level language program as an input and then transform the code and annotate it with parallel code annotations (e.g., OpenMP

OpenMP

OpenMP is an API that supports multi-platform shared memory multiprocessing programming in C, C++, and Fortran, on most processor architectures and operating systems, including Linux, Unix, AIX, Solaris, Mac OS X, and Microsoft Windows platforms...

) or language constructs (e.g. Fortran

Fortran

Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...

's DOALL statements).

Another purpose of source-to-source-compiling is translating legacy code to use the next version of the underlying programming language or an API that breaks backward compatibility. It will perform automatic code refactoring which is useful when the programs to refactor are outside the control of the original implementer (for example, converting programs from Python 2 to Python 3, or converting programs from an old API to the new API) or when the size of the program makes it impractical or time consuming to refactor it by hand.

DMS Software Reengineering Toolkit

The DMS Software Reengineering Toolkit is a proprietary set of program transformation tools available for automating custom source program analysis, modification, translation or generation of software systems for arbitrary mixtures of source languages for large scale software systems.DMS has been...

is a source-to-source program transformation tool, parameterized by explicit source and target (may be the same) computer language definitions. It can be used for translating from one computer language to another, for compiling domain-specific languages to a general purpose language, or for carrying out optimizations or massive modifications within a specific language. DMS has a library of language definitions for most widely used computer languages (including full C++

C++

C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...

, and a means for defining other languages which it does not presently know).

LLVM

Low Level Virtual Machine

The Low Level Virtual Machine is a compiler infrastructure written in C++ that is designed for compile-time, link-time, run-time, and "idle-time" optimization of programs written in arbitrary programming languages...

(LLVM) can translate from any language supported by gcc 4.2.1 (Ada

Ada (programming language)

Ada is a structured, statically typed, imperative, wide-spectrum, and object-oriented high-level computer programming language, extended from Pascal and other languages...

, C

C (programming language)

C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....

, C++

C++

, Fortran, Java

Java (programming language)

Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...

, Objective-C

Objective-C

Objective-C is a reflective, object-oriented programming language that adds Smalltalk-style messaging to the C programming language.Today, it is used primarily on Apple's Mac OS X and iOS: two environments derived from the OpenStep standard, though not compliant with it...

, or Objective-C++) or by clang

Clang

Clang is a compiler front end for the C, C++, Objective-C, and Objective-C++ programming languages. It uses the Low Level Virtual Machine as its back end, and Clang has been part of LLVM releases since LLVM 2.6....

to any of: C, C++, or MSIL

Common Intermediate Language

Common Intermediate Language is the lowest-level human-readable programming language defined by the Common Language Infrastructure specification and is used by the .NET Framework and Mono...

by way of the "arch" command in llvm-gcc.



% llvm-g++ x.cpp -o program

% llc -march=c program.bc -o program.c

% cc x.c



% llvm-g++ x.cpp -o program

% llc -march=msil program.bc -o program.msil

Refactoring tools

The refactoring tools automate transforming source code into another:

The Python 3000 2to3 tool transform non forward-compatible
Forward compatibility
Forward compatibility or upward compatibility is a compatibility concept for systems design, as e.g. backward compatibility. Forward compatibility aims at the ability of a design to gracefully accept input intended for later versions of itself...

Python 2 code into Python 3 code
Qt's qt3to4 tool convert non forward-compatible usage of the Qt3 API into Qt4 API usage.
Coccinelle
Coccinelle (software)
Coccinelle is a tool to match and transform the source code of programs written in the programming language C. Coccinelle was initially used to aid the evolution of Linux; with support for changes to library application programming interfaces such as renaming a function, adding a function...

uses semantic patch
Patch (computing)
A patch is a piece of software designed to fix problems with, or update a computer program or its supporting data. This includes fixing security vulnerabilities and other bugs, and improving the usability or performance...

es to describe refactoring to apply to C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....

code. It's been applied successfully to refactor the driver
Device driver
In computing, a device driver or software driver is a computer program allowing higher-level computer programs to interact with a hardware device....

s of the Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

kernel
Kernel (computing)
In computing, the kernel is the main component of most computer operating systems; it is a bridge between applications and the actual data processing done at the hardware level. The kernel's responsibilities include managing the system's resources...

due to kernel API changes.
RefactoringNG is a Netbeans
NetBeans
NetBeans refers to both a platform framework for Java desktop applications, and an integrated development environment for developing with Java, JavaScript, PHP, Python, Groovy, C, C++, Scala, Clojure, and others...

module for refactoring
Refactoring
Code refactoring is "disciplined technique for restructuring an existing body of code, altering its internal structure without changing its external behavior", undertaken in order to improve some of the nonfunctional attributes of the software....

Java
Java (programming language)
Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...

code where you can write transformations rules of a program's abstract syntax tree
Abstract syntax tree
In computer science, an abstract syntax tree , or just syntax tree, is a tree representation of the abstract syntactic structure of source code written in a programming language. Each node of the tree denotes a construct occurring in the source code. The syntax is 'abstract' in the sense that it...

.

Vala

Vala (programming language)

Vala is a programming language created with the goal of bringing modern language features to C, with no added runtime needs and with little overhead, by targeting the GObject object system. It is being developed by Jürg Billeter and Raffaele Sandrini. The syntax borrows heavily from C#...

, as another example, is compiled to C

C (programming language)

C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....

(with additional libraries such as GObject

GObject

The GLib Object System, or GObject, is a free software library providing a portable object system and transparent cross-language interoperability...

) before ever being compiled to native code

Machine code

Machine code or machine language is a system of impartible instructions executed directly by a computer's central processing unit. Each instruction performs a very specific task, typically either an operation on a unit of data Machine code or machine language is a system of impartible instructions...

DMS Software Reengineering Toolkit

LLVM

Refactoring tools

Vala

See also