Compiler - Computer Programming - UOZ

Compiler - Computer Programming - UOZ

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  Compiler Prepared By: Safeen Dlshad BafreenAmjad Darya Mahdi Harikar mikail University of Zakho College of Engineering Petroleum Engineering Department
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  Content  Introduction  TheStructure of a Compiler  The Phases of a Compiler  The Grouping of Phases  Interpreters & Compilers
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  Introduction • A compilertranslates (or Compiler) is a software which converts a program written in high level language (Source Language) to low level language (Object/Target/Machine Language). Compiler Compilation Error High Level Language Low Level Language
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  • Read andanalyze entire program • The compiler can spot some obvious programming mistakes. • There are thousands of source languages, ranging from traditional programming languages such as FORTRAN and Pascal to specialized languages. Introduction
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  • The basictasks that any compiler must perform are essentially the same. • By understanding these tasks, we can construct compilers for a wide variety of source languages and target machines using the same basic techniques. • The first real compiler – Throughout the 1950’s, compilers were considered notoriously difficult programs to write. – The first FORTRAN compiler, for example, took 18 staff-years to implement. Introduction
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  Any compiler mustperform two major tasks  Analysis an intermediate representation is created from the given source program. – Lexical Analyzer, Syntax Analyzer and Semantic Analyzer are the parts of this phase.  Synthesis of takes the tree structure and translates the operations therein into the target program. – Intermediate Code Generator, Code Generator, and Code Optimizer are the parts of this phase. The Structure of a Compiler Compile r Analysis Synthesi s
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  The Structure ofa Compiler Scanner Parser Semantic Routines Code Generator Optimizer Source Program Tokens Syntactic Structure Symbol and Attribute Tables (Used by all Phases of The Compiler) (Character Stream) Intermediate Representation Target machine code
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  The Phases ofa Compiler • Lexical Analyzer • Syntax Analyzer • Semantic Analyzer • Intermediate code generator • Code optimizer • Code generator
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  The Grouping ofPhases • Compiler front and back ends: – Front end: analysis (machine independent) – Back end: synthesis (machine • Compiler passes: – A collection of phases is done only once (single pass) or multiple times (multi pass)  Single pass: usually requires everything to be defined before being used in source program  Multi pass: compiler may have to keep entire program representation in memory
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  Interpreters & Compilers Compilers A program that translates a program from one language (the source) to another (the target)  Typical Implementations – FORTRAN, C, C++, Java, COBOL, etc. etc. – Strong need for optimization Compiler Error messages Source Program Target Program Input Output
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  Interpreters & Compilers Interpreters A program that reads a source program and produces the results of executing that program.  Typical Implementations – PERL, Python, awk, sed, sh, csh, postscript printer, Java VM – Effective if interpreter overhead is low relative to execution cost of language statements Interpreter Source Program Input Output Error messages
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  Interpreters & Compilers •An interpreter may need to process the same piece of the syntax tree (for example, the body of a loop) many times  interpretation is slower than executing a compiled program. • An interpreter executes the source program statement by statement  it can usually give better error diagnostics than a compiler. • Compilers and interpreters both must read the input – a stream of characters – and “understand” it; analysis w h i l e ( k < l e n g t h ) { <nl> <tab> i f ( a [ k ] > 0 ) <nl> <tab> <tab>{ n P o s + + ; } <nl> <tab> }
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