COMPILER DESIGN AND CONSTRUCTION

COMPILER DESIGN AND CONSTRUCTION

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  Intermediate Code Generation Presented By: AnilPokhrel BscCSIT VI sem
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  Contents • Introduction • Features •Why Intermediate code • Three Address statements • Quadruples • Conclusion 2
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  Introduction 3
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   Retargeting: Builda compiler for a new machine by attaching a new code generator to an existing front-end.  Optimization: reuse intermediate code optimizers in compilers for different languages and different machines 5
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  Why intermediate code 6
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  Three address code Most instruction of three address code is of the form  a = b op c  Example: a = b * c + 10  The three address code will be  t1 = b * C  t2 = t1 + 10  a = t2 7
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  Types of Three-addressStatements Assignment: – Binary: x := y op z – Unary: x := op y – “op” can be any reasonable arithmetic or logic operator
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  Copy: – Simple: x:= y – Indexed: x := y[i] or x[i] := y – Address and pointer manipulation: • x := &y
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  Jump: – Unconditional: gotoL – Conditional: if x relop y goto L1 [else goto L2 ], where relop is <,=, >, , or ≠. ≧ ≦
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  Quadruples • Quadruples consistsof four fields in the record structure • A quadruple is a record structure with four fields: op, arg1, arg2, and result
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  Quadruples Examp a :=b * -c + b * -c
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  Conclusion • Intermediate codeis the interface between front end and back end in a compiler • Ideally the details of source language are confined to the front end and the details of target machines to the back end
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  References  https://www.tutorialspoint.com/compiler_design/ compiler_design_intermediate_code_generation s.htm  https://www.geeksforgeeks.org/intermediate- code-generation-in-compiler-design/ https://www.javatpoint.com/intermediate-code 14
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