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Most compilers have at least the following compiler phases (which therefore occur at compile-time): syntax analysis, semantic analysis, and code generation.During optimization phases, constant expressions in the source code can also be evaluated at compile-time using compile-time execution, which reduces the constant expressions to a single value.
When code generation occurs at runtime, as in just-in-time compilation (JIT), it is important that the entire process be efficient with respect to space and time. For example, when regular expressions are interpreted and used to generate code at runtime, a non-deterministic finite-state machine is often generated instead of a deterministic one, because usually the former can be created more ...
Regardless of the exact number of phases in the compiler design, the phases can be assigned to one of three stages. The stages include a front end, a middle end, and a back end. The front end scans the input and verifies syntax and semantics according to a specific source language.
Program lifecycle phases are the stages a computer program undergoes, from initial creation to deployment and execution. The phases are edit time, compile time, link time, distribution time, installation time, load time, and run time. Lifecycle phases do not necessarily happen in a linear order, and they can be intertwined in various ways.
A multi-pass compiler is a type of compiler that processes the source code or abstract syntax tree of a program several times. This is in contrast to a one-pass compiler, which traverses the program only once. Each pass takes the result of the previous pass as the input, and creates an intermediate output.
A tracing JIT compiler goes through various phases at runtime. First, profiling information for loops is collected. After a scope loop has been identified, a special tracing phase is entered, which records all executed operations of that loop. This sequence of operations is called a trace.
The earliest published JIT compiler is generally attributed to work on LISP by John McCarthy in 1960. [4] In his seminal paper Recursive functions of symbolic expressions and their computation by machine, Part I, he mentions functions that are translated during runtime, thereby sparing the need to save the compiler output to punch cards [5] (although this would be more accurately known as a ...
Royce presented this model as an example of a flawed, non-working model. [9] The basic principles are: [1] The Project is divided into sequential phases, with some overlap and splashback acceptable between phases. Emphasis is on planning, time schedules, target dates, budgets, and implementation of an entire system at one time.