A computer program that converts an entire program into machine language at one time is called a/an
A computer program that converts an entire program into machine language at one time is called Compiler.
A Compiler is a computer program that translates code written in a high level language to a lower level language, object/machine code.
A compiler is computer software that transforms computer code written in one programming language (the source language) into another programming language (the target language). Compilers are a type of translator that support digital devices, primarily computers. The name compiler is primarily used for programs that translate source code from a high-level programming language to a lower level language (e.g., assembly language, object code, or machine code) to create an executable program.
Compilers are not the only translators 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 practice, an interpreter can be implemented for compiled languages and compilers can be implemented for interpreted languages.