This document provides an overview of compilers and their functions. It discusses: - The main phases of a compiler are analysis and synthesis. Analysis decomposes the source code into an intermediate representation, while synthesis generates the target program from that representation. - Compilers translate human-oriented programming languages into machine languages to be executed by computers. They perform analysis of the source program and synthesis of machine-language code. - Compilers generate different types of code like pure machine code, augmented machine code, or virtual machine code. They can also output assembly code or binary formats.

1. System Software (5KS03)
Unit 1 : Introduction to Compiling
Lecture : 1 Introduction to Compiling:
Phases of a compiler,
A S Kapse,
Assistant Professor,
Department Of Computer Sci. & Engineering
Anuradha Engineering College, Chikhli

2. Contents…
 Introduction to Compilers

3. Objectives…
 Upon completion of this lecture, you will be able
 To understand the basics Compiler
 To understand analysis and synthesis.
 To understand use and purpose of compiler

4. Review…./ Concepts
 What do you mean by Software?
 What do you mean by Operating System?
 What do you mean by system?
 What do you mean by compiler?

5. Introduction to Compilers
 As a Discipline, Involves Multiple CS&E Areas
 Programming Languages and Algorithms
 Theory of Computing & Software Engineering
 Computer Architecture & Operating Systems
 Has Deceivingly Simplistic Intent:
Compiler
Source
program
Target
Program
Error messages
Diverse & Varied

6. Classifications of Compilers
 Compilers Viewed from Many Perspectives
 However, All utilize same basic tasks to accomplish
their actions
Single Pass
Multiple Pass
Load & Go
Construction
Debugging
Optimizing
Functional

7. The Model
 The TWO Fundamental Parts:
 We Will Discuss Both in This Class, and
FOCUS on analysis.
Analysis:
Synthesis:
Decompose Source into an
intermediate representation
Target program generation
from representation

8. Important Notes
 Today: There are many Software Tools for helping with
the Analysis Part. This Wasn’t the Case in Early Days.
(some) analysis is also important in:
 Structure / Syntax directed editors: Force
“syntactically” correct code to be entered
 Pretty Printers: Standardized version for program
structure (i.e., blank space, indenting, etc.)
 Static Checkers: A “quick” compilation to detect
rudimentary errors
 Interpreters: “real” time execution of code a “line-at-a-
time”

9. Important Notes
 Compilation Is Not Limited to Programming Language
Applications
 Text Formatters
 LATEX & TROFF Are Languages Whose Commands
Format Text
 Silicon Compilers
 Textual / Graphical: Take Input and Generate Circuit Design
 Database Query Processors
 Database Query Languages Are Also a Programming Language
 Input is compiled Into a Set of Operations for Accessing the
Database

10. Overview and History (1)
 Cause
 Software for early computers was written in assembly language
 The benefits of reusing software on different CPUs started to
become significantly greater than the cost of writing a compiler
 The first real compiler
 FORTRAN compilers of the late 1950s
 18 person-years to build
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11. Overview and History (2)
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 Compiler technology
 is more broadly applicable and has been employed in
rather unexpected areas.
 Text-formatting languages,
like nroff and troff; preprocessor packages like eqn, tbl, pic
 Silicon compiler for the creation of VLSI circuits
 Command languages of OS
 Query languages of Database systems

12. What Do Compilers Do (1)
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 A compiler acts as a translator,
transforming human-oriented programming languages
into computer-oriented machine languages.
 Ignore machine-dependent details for programmer
Programming
Language
(Source)
Compiler
Machine
Language
(Target)

13. What Do Compilers Do (2)
 Compilers may generate three types of code:
 Pure Machine Code
 Machine instruction set without assuming the existence of any
operating system or library.
 Mostly being OS or embedded applications.
 Augmented Machine Code
 Code with OS routines and runtime support routines.
 More often
 Virtual Machine Code
 Virtual instructions, can be run on any architecture with a virtual
machine interpreter or a just-in-time compiler
 Ex. Java
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14. What Do Compilers Do (3)
 Another way that compilers
differ from one another is in the format of the target
machine code they generate:
 Assembly or other source format
 Relocatable binary
 Relative address
 A linkage step is required
 Absolute binary
 Absolute address
 Can be executed directly
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15. 15
 Any compiler must perform two major tasks
 Analysis of the source program
 Synthesis of a machine-language program
The Structure of a Compiler (1)
Compiler
Analysis Synthesis

16. Video
1. Introduction to Compiler.

17. Questions..
1. Define Compiler?

18. Homework..
1. What is Analysis and synthesis?