Lecture # 1
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A compiler is a program that translates source code written in one language into an equivalent target code in another language. Source code is usually written in a high-level language like C++ or Java, while target code is in machine language or assembly language. Compilers allow programmers to write code in languages that are easier for humans to read and write compared to machine language. Developing compilers involves understanding how to break down and analyze source code, generate equivalent target code, and address complex issues like language design and parsing algorithms.
Lecture # 1
- 2. Compiler Construction 2 Texts: Compiler Construction Principles and Practice by Kenneth C. Louden Compilers by Afred, Jaffery Ulman
- 4. 4 A Compiler is a program that Reads one Language (Source Code) and Translate it into an equivalent another Language (Target Code) CompilerSource Code Target Code
- 5. 5 Source Code usually in a high-level language, e.g. C++, JAVA, VB, FORTAN, PASCAL, etc. Target Code usually in machine language (object code) or assembly language (assembly code).
- 6. 6 Thus a Compiler specifically is an executable program that Reads a source code written in usually some high-level language and Translates it into an equivalent object code (machine language) or assembly code (assembly language) Compiler code in high-level language outputExecutable program in machine language executable program in machine code or assembly code input Definition
- 7. Complexity A compiler may be a complex from program from 10,000 to 100,000 lines of source code. 7
- 8. Uses compiler construction techniques have a large scope of applications and these are used almost in every field of computer sciences. 8
- 9. Our Task ? Our task is to understand the basic organization, structure and operations of a compiler. 9
- 10. Prerequisites Data Structures Discrete Mathematics Programming Languages Computer Architectures Assembly Languages Automata Theory (most helpful) 10
- 11. Design Issues Programming Language Design issues are actually Based on Language Design Issues so will discuss the both ones. 11
- 12. Why Compiler ? The Background 12
- 13. Machine Language With the advent of Stored Program Computer in late 1940’s by John Von Neumann, it was time To write Computer Programs (sequence of steps), that needed a Compiler to interpret these Programs. Initially these programs were written in the actual Machine Codes. exp. Task: move a number 2 to memory location 0000. Machine Code Instruction c7 06 0000 0002 13
- 14. Programming was much difficult in such language thus a symbolic language was introduced, and that language is called Assembly Language exp. Task: move a number 2 to memory location 0000. Machine Code Instruction: c7 06 0000 0002 Assembly Code Instruction: move x , 2 where x is symbolic memory location. 14 Assembly Language
- 15. Machine Dependency Difficult to Read (understand) & Write 15 Drawbacks
- 16. The next step in programming was the advent of high level languages, exp. Task: move a number 2 to memory location 0000. Machine Code Instruction: c7 06 0000 0002 Assembly Code Instruction: move x , 2 High Level Instruction: x = 2 ; 16 High Level Language
- 17. Machine Independency Easy to Read (understand) & Write Close to human nature mathematically & logically 17 Advantages
- 18. FORTRAN (1954 - 1957) FORTRAN was the first high level language developed in 195- 1954 Thus the first compiler for FORTRAN was developed by the team at IBM led by John Backus between 1954 and 1957. 18
- 19. Noam Chomsky When the first compiler was under construction during 195- 1954, Noam Chomsky was working on the structure of Natural Languages Chomsky’s research work also helped the construction of first compiler. 19
- 20. Chomsky Hierarchy Chomsky classified the languages according to the complexity of their grammar These Hierarchies are; Type 0 Type 1 Type 2 Type 3 Where each next type is an advance form of their previous type. 20
- 21. Parsing Problem The next step in the development of compilers was the study of parsing problem during 1960 to 1970, During that study CFL and the problem to find out efficient algorithms for the recognition of CFL were studied. 21
- 22. Recent Work Currently scientists are continuously working and trying to find efficient methods of object code generation. Its really difficult to generate truly optimal code, but they only increase its efficiency. Similarly work is being on the automation of different phases, i.e., scanner generators, parser Generators, etc. 22
- 23. Recent Work Scientists are also working to develop different sophisticated algorithms for pre analysis of source code, like Unification Algorithm Development of more enhanced and rich window based IDE’s Standardization of such environments. etc, 23
- 24. (1) for development of new languages. - language extensions & improvement - more rich/formal specification of languages - development of 4th generation languages (2) for Standardization of Construction Process. (3) for parallelizing compilers & related tools. (4) for new development platforms. 24 Importance
- 25. (5) theories learned in this course are applicable to other fields e.g., prototyping tools, database languages text formatter FSM (Finite State Machine) translator query interpreter command line interpreter interface programs Silicon Compilers, etc. (6) for improving capabilities of existing compiler/interpreter 25
- 26. Silicon compiler - A silicon compiler is a software system that takes a user's specifications and automatically generates an integrated circuit (IC). The process is sometimes referred to as hardware compilation. - Source language: conventional programming language - Variables Represents not the location but logical signals (0 or 1) or groups of signals in a switching circuit. - Output : circuit design in an appropriate language 26