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54-482: [REDACTED] Look up jml in Wiktionary, the free dictionary. JML may refer to: Java Modeling Language , a specification language for Java programs Journal of Memory and Language , abbreviated JML "Joiner, mover, leaver", a collection of business processes managing access to an organisation's systems within an identity lifecycle JML (John Mills Limited) ,

108-533: A basic block , to whole procedures, or even the whole program. There is a trade-off between the granularity of the optimizations and the cost of compilation. For example, peephole optimizations are fast to perform during compilation but only affect a small local fragment of the code, and can be performed independently of the context in which the code fragment appears. In contrast, interprocedural optimization requires more compilation time and memory space, but enable optimizations that are only possible by considering

162-412: A concrete syntax tree (CST, parse tree) and then transforming it into an abstract syntax tree (AST, syntax tree). In some cases additional phases are used, notably line reconstruction and preprocessing, but these are rare. The main phases of the front end include the following: The middle end, also known as optimizer, performs optimizations on the intermediate representation in order to improve

216-422: A PDP-7 in B. Unics eventually became spelled Unix. Bell Labs started the development and expansion of C based on B and BCPL. The BCPL compiler had been transported to Multics by Bell Labs and BCPL was a preferred language at Bell Labs. Initially, a front-end program to Bell Labs' B compiler was used while a C compiler was developed. In 1971, a new PDP-11 provided the resource to define extensions to B and rewrite

270-437: A Production Quality Compiler (PQC) from formal definitions of source language and the target. PQCC tried to extend the term compiler-compiler beyond the traditional meaning as a parser generator (e.g., Yacc ) without much success. PQCC might more properly be referred to as a compiler generator. PQCC research into code generation process sought to build a truly automatic compiler-writing system. The effort discovered and designed

324-450: A UK consumer brand JML Direct TV , a series of British television shopping channels owned by John Mills Limited South African Jewish Maritime League See also [ edit ] [REDACTED] Search for "jml" on Misplaced Pages. All pages with titles beginning with JML All pages with titles beginning with Jml All pages with titles containing JML JMI (disambiguation) Topics referred to by

378-405: A compiler up into small programs is a technique used by researchers interested in producing provably correct compilers. Proving the correctness of a set of small programs often requires less effort than proving the correctness of a larger, single, equivalent program. Regardless of the exact number of phases in the compiler design, the phases can be assigned to one of three stages. The stages include

432-432: A component of an IDE (VADS, Eclipse, Ada Pro). The interrelationship and interdependence of technologies grew. The advent of web services promoted growth of web languages and scripting languages. Scripts trace back to the early days of Command Line Interfaces (CLI) where the user could enter commands to be executed by the system. User Shell concepts developed with languages to write shell programs. Early Windows designs offered

486-552: A documentation generator jmldoc which produces Javadoc documentation augmented with extra information from JML annotations, and a unit test generator jmlunit which generates JUnit test code from JML annotations. Independent groups are working on tools that make use of JML annotations. These include: Compiler In computing , a compiler is a computer program that translates computer code written in one programming language (the source language) into another language (the target language). The name "compiler"

540-608: A front end, a middle end, and a back end. This front/middle/back-end approach makes it possible to combine front ends for different languages with back ends for different CPUs while sharing the optimizations of the middle end. Practical examples of this approach are the GNU Compiler Collection , Clang ( LLVM -based C/C++ compiler), and the Amsterdam Compiler Kit , which have multiple front-ends, shared optimizations and multiple back-ends. The front end analyzes

594-527: A grammar for the language, though in more complex cases these require manual modification. The lexical grammar and phrase grammar are usually context-free grammars , which simplifies analysis significantly, with context-sensitivity handled at the semantic analysis phase. The semantic analysis phase is generally more complex and written by hand, but can be partially or fully automated using attribute grammars . These phases themselves can be further broken down: lexing as scanning and evaluating, and parsing as building

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648-432: A result, compilers were split up into smaller programs which each made a pass over the source (or some representation of it) performing some of the required analysis and translations. The ability to compile in a single pass has classically been seen as a benefit because it simplifies the job of writing a compiler and one-pass compilers generally perform compilations faster than multi-pass compilers . Thus, partly driven by

702-431: A simple batch programming capability. The conventional transformation of these language used an interpreter. While not widely used, Bash and Batch compilers have been written. More recently sophisticated interpreted languages became part of the developers tool kit. Modern scripting languages include PHP, Python, Ruby and Lua. (Lua is widely used in game development.) All of these have interpreter and compiler support. "When

756-489: Is Open64 , which is used by many organizations for research and commercial purposes. Due to the extra time and space needed for compiler analysis and optimizations, some compilers skip them by default. Users have to use compilation options to explicitly tell the compiler which optimizations should be enabled. The back end is responsible for the CPU architecture specific optimizations and for code generation . The main phases of

810-608: Is also commercial support, for example, AdaCore, was founded in 1994 to provide commercial software solutions for Ada. GNAT Pro includes the GNU GCC based GNAT with a tool suite to provide an integrated development environment . High-level languages continued to drive compiler research and development. Focus areas included optimization and automatic code generation. Trends in programming languages and development environments influenced compiler technology. More compilers became included in language distributions (PERL, Java Development Kit) and as

864-512: Is different from Wikidata All article disambiguation pages All disambiguation pages Java Modeling Language Various verification tools, such as a runtime assertion checker and the Extended Static Checker ( ESC/Java ) aid development. JML is a behavioural interface specification language for Java modules. JML provides semantics to formally describe the behavior of a Java module, preventing ambiguity with regard to

918-446: Is favored due to its modularity and separation of concerns . Most commonly, the frontend is broken into three phases: lexical analysis (also known as lexing or scanning), syntax analysis (also known as scanning or parsing), and semantic analysis . Lexing and parsing comprise the syntactic analysis (word syntax and phrase syntax, respectively), and in simple cases, these modules (the lexer and parser) can be automatically generated from

972-417: Is primarily used for programs that translate source code from a high-level programming language to a low-level programming language (e.g. assembly language , object code , or machine code ) to create an executable program. There are many different types of compilers which produce output in different useful forms. A cross-compiler produces code for a different CPU or operating system than

1026-570: The (since 1995, object-oriented) programming language Ada . The Ada STONEMAN document formalized the program support environment (APSE) along with the kernel (KAPSE) and minimal (MAPSE). An Ada interpreter NYU/ED supported development and standardization efforts with the American National Standards Institute (ANSI) and the International Standards Organization (ISO). Initial Ada compiler development by

1080-576: The Early PL/I (EPL) compiler by Doug McIlory and Bob Morris from Bell Labs. EPL supported the project until a boot-strapping compiler for the full PL/I could be developed. Bell Labs left the Multics project in 1969, and developed a system programming language B based on BCPL concepts, written by Dennis Ritchie and Ken Thompson . Ritchie created a boot-strapping compiler for B and wrote Unics (Uniplexed Information and Computing Service) operating system for

1134-518: The Sun 3/60 Solaris targeted to Motorola 68020 in an Army CECOM evaluation. There were soon many Ada compilers available that passed the Ada Validation tests. The Free Software Foundation GNU project developed the GNU Compiler Collection (GCC) which provides a core capability to support multiple languages and targets. The Ada version GNAT is one of the most widely used Ada compilers. GNAT is free but there

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1188-640: The U.S. Military Services included the compilers in a complete integrated design environment along the lines of the STONEMAN document. Army and Navy worked on the Ada Language System (ALS) project targeted to DEC/VAX architecture while the Air Force started on the Ada Integrated Environment (AIE) targeted to IBM 370 series. While the projects did not provide the desired results, they did contribute to

1242-465: The University of Cambridge was originally developed as a compiler writing tool. Several compilers have been implemented, Richards' book provides insights to the language and its compiler. BCPL was not only an influential systems programming language that is still used in research but also provided a basis for the design of B and C languages. BLISS (Basic Language for Implementation of System Software)

1296-435: The basis of digital modern computing development during World War II. Primitive binary languages evolved because digital devices only understand ones and zeros and the circuit patterns in the underlying machine architecture. In the late 1940s, assembly languages were created to offer a more workable abstraction of the computer architectures. Limited memory capacity of early computers led to substantial technical challenges when

1350-433: The behavior of multiple functions simultaneously. Interprocedural analysis and optimizations are common in modern commercial compilers from HP , IBM , SGI , Intel , Microsoft , and Sun Microsystems . The free software GCC was criticized for a long time for lacking powerful interprocedural optimizations, but it is changing in this respect. Another open source compiler with full analysis and optimization infrastructure

1404-584: The compiler. By 1973 the design of C language was essentially complete and the Unix kernel for a PDP-11 was rewritten in C. Steve Johnson started development of Portable C Compiler (PCC) to support retargeting of C compilers to new machines. Object-oriented programming (OOP) offered some interesting possibilities for application development and maintenance. OOP concepts go further back but were part of LISP and Simula language science. Bell Labs became interested in OOP with

1458-407: The development of C++ . C++ was first used in 1980 for systems programming. The initial design leveraged C language systems programming capabilities with Simula concepts. Object-oriented facilities were added in 1983. The Cfront program implemented a C++ front-end for C84 language compiler. In subsequent years several C++ compilers were developed as C++ popularity grew. In many application domains,

1512-546: The development of compiler technology: Early operating systems and software were written in assembly language. In the 1960s and early 1970s, the use of high-level languages for system programming was still controversial due to resource limitations. However, several research and industry efforts began the shift toward high-level systems programming languages, for example, BCPL , BLISS , B , and C . BCPL (Basic Combined Programming Language) designed in 1966 by Martin Richards at

1566-424: The development of high-level languages followed naturally from the capabilities offered by digital computers. High-level languages are formal languages that are strictly defined by their syntax and semantics which form the high-level language architecture. Elements of these formal languages include: The sentences in a language may be defined by a set of rules called a grammar. Backus–Naur form (BNF) describes

1620-424: The early days, the approach taken to compiler design was directly affected by the complexity of the computer language to be processed, the experience of the person(s) designing it, and the resources available. Resource limitations led to the need to pass through the source code more than once. A compiler for a relatively simple language written by one person might be a single, monolithic piece of software. However, as

1674-491: The field of compiling began in the late 50s, its focus was limited to the translation of high-level language programs into machine code ... The compiler field is increasingly intertwined with other disciplines including computer architecture, programming languages, formal methods, software engineering, and computer security." The "Compiler Research: The Next 50 Years" article noted the importance of object-oriented languages and Java. Security and parallel computing were cited among

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1728-461: The first (algorithmic) programming language for computers called Plankalkül ("Plan Calculus"). Zuse also envisioned a Planfertigungsgerät ("Plan assembly device") to automatically translate the mathematical formulation of a program into machine-readable punched film stock . While no actual implementation occurred until the 1970s, it presented concepts later seen in APL designed by Ken Iverson in

1782-423: The first compilers were designed. Therefore, the compilation process needed to be divided into several small programs. The front end programs produce the analysis products used by the back end programs to generate target code. As computer technology provided more resources, compiler designs could align better with the compilation process. It is usually more productive for a programmer to use a high-level language, so

1836-559: The first pass needs to gather information about declarations appearing after statements that they affect, with the actual translation happening during a subsequent pass. The disadvantage of compiling in a single pass is that it is not possible to perform many of the sophisticated optimizations needed to generate high quality code. It can be difficult to count exactly how many passes an optimizing compiler makes. For instance, different phases of optimization may analyse one expression many times but only analyse another expression once. Splitting

1890-933: The form of expressions without a change of language; and compiler-compilers , compilers that produce compilers (or parts of them), often in a generic and reusable way so as to be able to produce many differing compilers. A compiler is likely to perform some or all of the following operations, often called phases: preprocessing , lexical analysis , parsing , semantic analysis ( syntax-directed translation ), conversion of input programs to an intermediate representation , code optimization and machine specific code generation . Compilers generally implement these phases as modular components, promoting efficient design and correctness of transformations of source input to target output. Program faults caused by incorrect compiler behavior can be very difficult to track down and work around; therefore, compiler implementers invest significant effort to ensure compiler correctness . Compilers are not

1944-416: The form of annotations in comments. Java comments are interpreted as JML annotations when they begin with an @ sign. That is, comments of the form or Basic JML syntax provides the following keywords Basic JML also provides the following expressions as well as standard Java syntax for logical and, or, and not. JML annotations also have access to Java objects, object methods and operators that are within

1998-454: The future research targets. A compiler implements a formal transformation from a high-level source program to a low-level target program. Compiler design can define an end-to-end solution or tackle a defined subset that interfaces with other compilation tools e.g. preprocessors, assemblers, linkers. Design requirements include rigorously defined interfaces both internally between compiler components and externally between supporting toolsets. In

2052-421: The idea of using a higher-level language quickly caught on. Because of the expanding functionality supported by newer programming languages and the increasing complexity of computer architectures, compilers became more complex. DARPA (Defense Advanced Research Projects Agency) sponsored a compiler project with Wulf's CMU research team in 1970. The Production Quality Compiler-Compiler PQCC design would produce

2106-434: The late 1950s. APL is a language for mathematical computations. Between 1949 and 1951, Heinz Rutishauser proposed Superplan , a high-level language and automatic translator. His ideas were later refined by Friedrich L. Bauer and Klaus Samelson . High-level language design during the formative years of digital computing provided useful programming tools for a variety of applications: Compiler technology evolved from

2160-651: The module designers' intentions. JML inherits ideas from Eiffel , Larch and the Refinement Calculus , with the goal of providing rigorous formal semantics while still being accessible to any Java programmer. Various tools are available that make use of JML's behavioral specifications. Because specifications can be written as annotations in Java program files, or stored in separate specification files, Java modules with JML specifications can be compiled unchanged with any Java compiler. JML specifications are added to Java code in

2214-408: The need for a strictly defined transformation of the high-level source program into a low-level target program for the digital computer. The compiler could be viewed as a front end to deal with the analysis of the source code and a back end to synthesize the analysis into the target code. Optimization between the front end and back end could produce more efficient target code. Some early milestones in

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2268-475: The one on which the cross-compiler itself runs. A bootstrap compiler is often a temporary compiler, used for compiling a more permanent or better optimised compiler for a language. Related software include decompilers , programs that translate from low-level languages to higher level ones; programs that translate between high-level languages, usually called source-to-source compilers or transpilers ; language rewriters , usually programs that translate

2322-570: The only language processor used to transform source programs. An interpreter is computer software that transforms and then executes the indicated operations. The translation process influences the design of computer languages, which leads to a preference of compilation or interpretation. In theory, a programming language can have both a compiler and an interpreter. In practice, programming languages tend to be associated with just one (a compiler or an interpreter). Theoretical computing concepts developed by scientists, mathematicians, and engineers formed

2376-641: The overall effort on Ada development. Other Ada compiler efforts got underway in Britain at the University of York and in Germany at the University of Karlsruhe. In the U. S., Verdix (later acquired by Rational) delivered the Verdix Ada Development System (VADS) to the Army. VADS provided a set of development tools including a compiler. Unix/VADS could be hosted on a variety of Unix platforms such as DEC Ultrix and

2430-511: The performance and the quality of the produced machine code. The middle end contains those optimizations that are independent of the CPU architecture being targeted. The main phases of the middle end include the following: Compiler analysis is the prerequisite for any compiler optimization, and they tightly work together. For example, dependence analysis is crucial for loop transformation . The scope of compiler analysis and optimizations vary greatly; their scope may range from operating within

2484-639: The phase structure of the PQC. The BLISS-11 compiler provided the initial structure. The phases included analyses (front end), intermediate translation to virtual machine (middle end), and translation to the target (back end). TCOL was developed for the PQCC research to handle language specific constructs in the intermediate representation. Variations of TCOL supported various languages. The PQCC project investigated techniques of automated compiler construction. The design concepts proved useful in optimizing compilers and compilers for

2538-429: The resource limitations of early systems, many early languages were specifically designed so that they could be compiled in a single pass (e.g., Pascal ). In some cases, the design of a language feature may require a compiler to perform more than one pass over the source. For instance, consider a declaration appearing on line 20 of the source which affects the translation of a statement appearing on line 10. In this case,

2592-403: The same term [REDACTED] This disambiguation page lists articles associated with the title JML . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=JML&oldid=1148105005 " Category : Disambiguation pages Hidden categories: Short description

2646-595: The scope of the method being annotated and that have appropriate visibility. These are combined to provide formal specifications of the properties of classes, fields and methods. For example, an annotated example of a simple banking class may look like Full documentation of JML syntax is available in the JML Reference Manual . A variety of tools provide functionality based on JML annotations. The Iowa State JML tools provide an assertion checking compiler jmlc which converts JML annotations into runtime assertions,

2700-490: The source code to build an internal representation of the program, called the intermediate representation (IR). It also manages the symbol table , a data structure mapping each symbol in the source code to associated information such as location, type and scope. While the frontend can be a single monolithic function or program, as in a scannerless parser , it was traditionally implemented and analyzed as several phases, which may execute sequentially or concurrently. This method

2754-469: The source language grows in complexity the design may be split into a number of interdependent phases. Separate phases provide design improvements that focus development on the functions in the compilation process. Classifying compilers by number of passes has its background in the hardware resource limitations of computers. Compiling involves performing much work and early computers did not have enough memory to contain one program that did all of this work. As

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2808-440: The syntax of "sentences" of a language. It was developed by John Backus and used for the syntax of Algol 60 . The ideas derive from the context-free grammar concepts by linguist Noam Chomsky . "BNF and its extensions have become standard tools for describing the syntax of programming notations. In many cases, parts of compilers are generated automatically from a BNF description." Between 1942 and 1945, Konrad Zuse designed

2862-432: Was developed for a Digital Equipment Corporation (DEC) PDP-10 computer by W. A. Wulf's Carnegie Mellon University (CMU) research team. The CMU team went on to develop BLISS-11 compiler one year later in 1970. Multics (Multiplexed Information and Computing Service), a time-sharing operating system project, involved MIT , Bell Labs , General Electric (later Honeywell ) and was led by Fernando Corbató from MIT. Multics

2916-466: Was written in the PL/I language developed by IBM and IBM User Group. IBM's goal was to satisfy business, scientific, and systems programming requirements. There were other languages that could have been considered but PL/I offered the most complete solution even though it had not been implemented. For the first few years of the Multics project, a subset of the language could be compiled to assembly language with

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