Compiler Design Tutorial Last Updated : 06 Feb, 2025 Comments Improve Suggest changes Like Article Like Report A compiler is software that translates or converts a program written in a high-level language (Source Language) into a low-level language (Machine Language or Assembly Language). Compiler design is the process of developing a compiler.It involves many stages like lexical analysis, syntax analysis (parsing), semantic analysis, code generation, optimization, etc. The Key objectives of compiler design are to automate the translation process, check correctness of input code, and reporting errors in source code. It acts as the "translator" of the programming world, bridging the gap between human-readable code and machine-understandable instructions.Most of the early high level languages like C and C++ were compiled. However modern languages like Java and Python use both interpreter and compiler. Please note that compiler only translates but interpreter runs as well. Introduction :Introduction of Compiler designCompiler construction toolsPhases of a CompilerSymbol Table in CompilerError detection and Recovery in CompilerError Handling in Compiler DesignLanguage Processors: Assembler, Compiler and InterpreterGeneration of Programming LanguagesLexical Analysis :Lexical AnalysisC program to detect tokens in a C programFlex (Fast Lexical Analyzer Generator ) Quiz on Lexical AnalysisSyntax Analysis :Introduction to Syntax AnalysisFIRST and FOLLOWClassification of Context Free Grammars(CFG)Ambiguous GrammarIntroduction to ParsersClassification of top down parsersBottom Up ParserShift Reduce Parser in CompilerSLR, CLR and LALR ParsersTheory of Computation | Operator grammar and precedence parserSyntax Directed Translation :Syntax Directed TranslationS – attributed and L – attributed SDTs in Syntax directed translationQuiz on Parsing and Syntax Directed TranslationCode Generation and Optimization :Code OptimizationIntermediate Code GenerationIssues in the design of a code generatorThree address code in CompilerCompiler Design | Detection of a Loop in Three Address CodeIntroduction of Object CodeData flow analysis in CompilerQuiz on Code Generation and OptimizationRuntime Environments :Static and Dynamic ScopingCompiler Design | Runtime EnvironmentsCompiler Design | LinkerLoader in C/C++Developing a Linux based shellConclusionMastering compiler design is essential for anyone delving into programming languages and software development. Throughout this compiler design tutorial, we've covered crucial concepts such as lexical analysis, syntax analysis, semantic analysis, optimization techniques, and code generation. By understanding these foundations, you're equipped to build efficient compilers that transform source code into executable programs seamlessly. GATE | Previous Years Questions : Set – 1 , Set – 2Quiz on Compiler DesignPlease write comments if you find anything incorrect, or if you want to share more information about the topic discussed above. Comment More infoAdvertise with us Next Article Introduction of Compiler Design kartik Follow Improve Article Tags : Compiler Design GATE CS GateCS2023 Similar Reads Compiler Design Tutorial A compiler is software that translates or converts a program written in a high-level language (Source Language) into a low-level language (Machine Language or Assembly Language). Compiler design is the process of developing a compiler.It involves many stages like lexical analysis, syntax analysis (p 3 min read Introduction Introduction of Compiler DesignA compiler is software that translates or converts a program written in a high-level language (Source Language) into a low-level language (Machine Language or Assembly Language). Compiler design is the process of developing a compiler.The development of compilers is closely tied to the evolution of 9 min read Compiler construction toolsThe compiler writer can use some specialized tools that help in implementing various phases of a compiler. These tools assist in the creation of an entire compiler or its parts. Some commonly used compiler construction tools include: Parser Generator - It produces syntax analyzers (parsers) from the 4 min read Phases of a CompilerA compiler is a software tool that converts high-level programming code into machine code that a computer can understand and execute. It acts as a bridge between human-readable code and machine-level instructions, enabling efficient program execution. The process of compilation is divided into six p 10 min read Symbol Table in CompilerEvery compiler uses a symbol table to track all variables, functions, and identifiers in a program. It stores information such as the name, type, scope, and memory location of each identifier. Built during the early stages of compilation, the symbol table supports error checking, scope management, a 8 min read Error Detection and Recovery in CompilerError detection and recovery are essential functions of a compiler to ensure that a program is correctly processed. Error detection refers to identifying mistakes in the source code, such as syntax, semantic, or logical errors. When an error is found, the compiler generates an error message to help 6 min read Error Handling in Compiler DesignDuring the process of language translation, the compiler can encounter errors. While the compiler might not always know the exact cause of the error, it can detect and analyze the visible problems. The main purpose of error handling is to assist the programmer by pointing out issues in their code. E 5 min read Language Processors: Assembler, Compiler and InterpreterComputer programs are generally written in high-level languages (like C++, Python, and Java). A language processor, or language translator, is a computer program that convert source code from one programming language to another language or to machine code (also known as object code). They also find 5 min read Generation of Programming LanguagesProgramming languages have evolved significantly over time, moving from fundamental machine-specific code to complex languages that are simpler to write and understand. Each new generation of programming languages has improved, allowing developers to create more efficient, human-readable, and adapta 6 min read Lexical AnalysisIntroduction of Lexical AnalysisLexical analysis, also known as scanning is the first phase of a compiler which involves reading the source program character by character from left to right and organizing them into tokens. Tokens are meaningful sequences of characters. There are usually only a small number of tokens for a programm 6 min read Flex (Fast Lexical Analyzer Generator)Flex (Fast Lexical Analyzer Generator), or simply Flex, is a tool for generating lexical analyzers scanners or lexers. Written by Vern Paxson in C, circa 1987, Flex is designed to produce lexical analyzers that is faster than the original Lex program. Today it is often used along with Berkeley Yacc 7 min read Introduction of Finite AutomataFinite automata are abstract machines used to recognize patterns in input sequences, forming the basis for understanding regular languages in computer science. They consist of states, transitions, and input symbols, processing each symbol step-by-step. If the machine ends in an accepting state after 4 min read Ambiguous GrammarContext-Free Grammars (CFGs) is a way to describe the structure of a language, such as the rules for building sentences in a language or programming code. These rules help define how different symbols can be combined to create valid strings (sequences of symbols).CFGs can be divided into two types b 7 min read Syntax AnalysisIntroduction to Syntax Analysis in Compiler DesignSyntax Analysis (also known as parsing) is the step after Lexical Analysis. The Lexical analysis breaks source code into tokens.Tokens are inputs for Syntax Analysis.The goal of Syntax Analysis is to interpret the meaning of these tokens. It checks whether the tokens produced by the lexical analyzer 7 min read FIRST and FOLLOW in Compiler DesignIn compiler design, FIRST and FOLLOW are two sets used to help parsers understand how to process a grammar.FIRST Set: The FIRST set of a non-terminal contains all the terminal symbols that can appear at the beginning of any string derived from that non-terminal. In other words, it tells us which ter 6 min read FIRST Set in Syntax AnalysisThe FIRST set is used in syntax analysis to identify which terminal symbols can appear at the start of strings derived from a non-terminal. It is crucial for LL and LR parsers, helping them decide which rules to apply.To compute the FIRST set:Add the terminal itself to the FIRST set for all terminal 6 min read FOLLOW Set in Syntax AnalysisThe FOLLOW set in Syntax Analysis is a group of symbols that can come right after a non-terminal in a grammar. It helps parsers figure out what should appear next in the input while checking if the grammar is correct. The FOLLOW set is important for building parsing tables, especially in LL(1) parse 5 min read Classification of Context Free GrammarsA Context-Free Grammar (CFG) is a formal rule system used to describe the syntax of programming languages in compiler design. It provides a set of production rules that specify how symbols (terminals and non-terminals) can be combined to form valid sentences in the language. CFGs are important in th 4 min read ParsersParsing - Introduction to ParsersParsing, also known as syntactic analysis, is the process of analyzing a sequence of tokens to determine the grammatical structure of a program. It takes the stream of tokens, which are generated by a lexical analyzer or tokenizer, and organizes them into a parse tree or syntax tree.The parse tree v 6 min read Classification of Top Down ParsersTop-down parsing is a way of analyzing a sentence or program by starting with the start symbol (the root of the parse tree) and working down to the leaves (the actual input symbols). It tries to match the input string by expanding the start symbol using grammar rules. The process of constructing the 4 min read Bottom-up ParsersBottom-up parsing is a type of syntax analysis method where the parser starts from the input symbols (tokens) and attempts to reduce them to the start symbol of the grammar (usually denoted as S). The process involves applying production rules in reverse, starting from the leaves of the parse tree a 13 min read Shift Reduce Parser in CompilerShift-reduce parsing is a popular bottom-up technique used in syntax analysis, where the goal is to create a parse tree for a given input based on grammar rules. The process works by reading a stream of tokens (the input), and then working backwards through the grammar rules to discover how the inpu 11 min read SLR Parser (with Examples)LR parsers is an efficient bottom-up syntax analysis technique that can be used to parse large classes of context-free grammar is called LR(k) parsing. L stands for left-to-right scanningR stands for rightmost derivation in reversek is several input symbols. when k is omitted k is assumed to be 1.Ad 4 min read CLR Parser (with Examples)LR parsers :It is an efficient bottom-up syntax analysis technique that can be used to parse large classes of context-free grammar is called LR(k) parsing. L stands for the left to right scanningR stands for rightmost derivation in reversek stands for no. of input symbols of lookahead Advantages of 7 min read Construction of LL(1) Parsing TableParsing is an essential part of computer science, especially in compilers and interpreters. From the various parsing techniques, LL(1) parsing is best. It uses a predictive, top-down approach. This allows efficient parsing without backtracking. This article will explore parsing and LL(1) parsing. It 6 min read LALR Parser (with Examples)LALR Parser :LALR Parser is lookahead LR parser. It is the most powerful parser which can handle large classes of grammar. The size of CLR parsing table is quite large as compared to other parsing table. LALR reduces the size of this table.LALR works similar to CLR. The only difference is , it combi 6 min read Syntax Directed TranslationSyntax Directed Translation in Compiler DesignSyntax-Directed Translation (SDT) is a method used in compiler design to convert source code into another form while analyzing its structure. It integrates syntax analysis (parsing) with semantic rules to produce intermediate code, machine code, or optimized instructions.In SDT, each grammar rule is 8 min read S - Attributed and L - Attributed SDTs in Syntax Directed TranslationIn Syntax-Directed Translation (SDT), the rules are those that are used to describe how the semantic information flows from one node to the other during the parsing phase. SDTs are derived from context-free grammars where referring semantic actions are connected to grammar productions. Such action c 4 min read Parse Tree in Compiler DesignIn compiler design, the Parse Tree depicts the syntactic structure of a string in accordance with a given grammar. It was created during the parsing phase of compilation, wherein syntax of the input source code is analyzed. A parse tree is a useful way of showing how a string or program would be der 4 min read Parse Tree and Syntax TreeParse Tree and Syntax tree are tree structures that represent the structure of a given input according to a formal grammar. They play an important role in understanding and verifying whether an input string aligns with the language defined by a grammar. These terms are often used interchangeably but 4 min read Code Generation and OptimizationCode Optimization in Compiler DesignCode optimization is a crucial phase in compiler design aimed at enhancing the performance and efficiency of the executable code. By improving the quality of the generated machine code optimizations can reduce execution time, minimize resource usage, and improve overall system performance. This proc 9 min read Intermediate Code Generation in Compiler DesignIn the analysis-synthesis model of a compiler, the front end of a compiler translates a source program into an independent intermediate code, then the back end of the compiler uses this intermediate code to generate the target code (which can be understood by the machine). The benefits of using mach 6 min read Issues in the design of a code generatorA code generator is a crucial part of a compiler that converts the intermediate representation of source code into machine-readable instructions. Its main task is to produce the correct and efficient code that can be executed by a computer. The design of the code generator should ensure that it is e 7 min read Three address code in CompilerTAC is an intermediate representation of three-address code utilized by compilers to ease the process of code generation. Complex expressions are, therefore, decomposed into simple steps comprising, at most, three addresses: two operands and one result using this code. The results from TAC are alway 6 min read Data flow analysis in CompilerData flow is analysis that determines the information regarding the definition and use of data in program. With the help of this analysis, optimization can be done. In general, its process in which values are computed using data flow analysis. The data flow property represents information that can b 6 min read Compiler Design | Detection of a Loop in Three Address CodePrerequisite - Three address code in Compiler Loop optimization is the phase after the Intermediate Code Generation. The main intention of this phase is to reduce the number of lines in a program. In any program majority of the time is spent actually inside the loop for an iterative program. In the 3 min read Introduction of Object Code in Compiler DesignLet assume that you have a C program then, you give it to the compiler and compiler will produce the output in assembly code. Now, that assembly language code will be given to the assembler and assembler will produce some code and that code is known as Object Code. Object CodeObject Code is a key co 6 min read Data flow analysis in CompilerData flow is analysis that determines the information regarding the definition and use of data in program. With the help of this analysis, optimization can be done. In general, its process in which values are computed using data flow analysis. The data flow property represents information that can b 6 min read Runtime EnvironmentsStatic and Dynamic ScopingThe scope of a variable x in the region of the program in which the use of x refers to its declaration. One of the basic reasons for scoping is to keep variables in different parts of the program distinct from one another. Since there are only a small number of short variable names, and programmers 6 min read Runtime Environments in Compiler DesignA translation needs to relate the static source text of a program to the dynamic actions that must occur at runtime to implement the program. The program consists of names for procedures, identifiers, etc., that require mapping with the actual memory location at runtime. Runtime environment is a sta 8 min read LinkerA linker is an essential tool in the process of compiling a program. It helps combine various object modules (output from the assembler) into a single executable file that can be run on a system. The linker’s job is to manage and connect different pieces of code and data, ensuring that all reference 8 min read Loader in C/C++The loader is the program of the operating system which loads the executable from the disk into the primary memory(RAM) for execution. It allocates the memory space to the executable module in the main memory and then transfers control to the beginning instruction of the program. The loader is an im 3 min read Compiler Design LMNLast Minute Notes - Compiler DesignIn computer science, compiler design is the study of how to build a compiler, which is a program that translates high-level programming languages (like Python, C++, or Java) into machine code that a computer's hardware can execute directly. The focus is on how the translation happens, ensuring corre 13 min read Compiler Design GATE PYQ's and MCQsCompiler Design - GATE CSE Previous Year QuestionsIn this article, we are mainly focusing on the Compiler Design GATE Questions that have been asked in Previous Years, with their solutions. And where an explanation is required, we have also provided the reason. Topic-Wise Quizzes to Practice Previous Year's QuestionsLexical AnalysisParsingSyntax-Di 1 min read Like