Compiler Design codes for the course 21CS63 conducted at RV College of Engineering, Bangalore.

• The following codes are written in C and are meant to be compiled with CC or GCC compilers.

LABEXAM TO REPO MAPPING

LAB Question	Repo Program path
Words,lines,chars,Special Characters	Link
a^m b^m+n c^n	Link
Integers and Fractions	Link
Arithmetic Expression	Link
Remove comment lines	Link
Nested For loops	Link
Number of identifiers and operators	Link
Nested IF statements	Link
Variable Declaration	Link
Three address code	Link
Function definition	Link
Assembly code generation	Link

Pre-requisites

• Need to have the following installed :
  • GCC Compiler
  • Flex
  • Yacc

How to run the code

Running just the Lexical Analyser

 lex <filename>.l
 gcc lex.yy.c
 ./a.out

Running the Lexical Analyser and Parser

 lex <filename>.l
 yacc -d <filename>.y
 gcc lex.yy.c y.tab.c -lfl
 ./a.out

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Input format for each of the programs

1. a. Count the number of characters, words, lines and special characters in a given input file.

    any string with numbers and special characters
   

   b Validate the strings of the type a^m b^m+n c^n where m,n>=0

     aabbcc
     abc
     ab
     bc
   

2. a. Count the number of positive and negetive integers and positive and negetive fractions

   > 1 -2 3/4 -5/6 7/-8 -9/-10 +11/12
   > // Just give a series fo space separated numbers
   

   b. Evaluate a given arithmetic expression with + - * / operators.

   1+2*3/4-5
   

3. a. Count the number of valid nested FOR loops

   for(a;b;c){}
   for(a;b;c){for(a;b;c){d;}}
   

   b. Validate function defination

   int main(){};
   int foo(int a){}
   int bar(int a,int b){return a;}
   

4. Generate the intermediate 3 address code and quadruples for a given expression

   a=b+c*d
   a+b+c+d+e+f
   a=(b+d)*(c+e)
   

5. Generate the assembly code for a given set of arithmetic expressions

   ./outputfilename.out < input.txt
   

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LLVM Programs

Program 1

This program is to print the unoptimised and optimised code for a bubble sort code

# to print the unoptimised assembly code
clang filename.c -S -emit-llvm -o filename

# to print the optimised assembly code
clang filename.c -S -emit-llvm -o filename -O3

Program 2

This program is to print the unoptimised and optimised code for a binary search code

# to print the unoptimised assembly code
clang filename.c -S -emit-llvm -o filename

# to print the optimised assembly code
clang filename.c -S -emit-llvm -o filename -O3

Program 3

this is about loop unrolling

# comment out the unroll pragma to see the difference
clang filename.c -S -emit-llvm -o filename

# for unrolled optimisation
clanf filename.c -S -emit-llvm -o filename -O3

Change Log

Version 1

• Added all 5 programs
• Had some conflicts in Shift/Reduce and Reduce/ Reduce

Version 2

• @DeathStroke1991(https://github.com/DeathStroke19891) Fixed the issues in 3a and 3b
• Added comments on grammer.

Version 3

• Added LLVM programs
• Added the new commands to run the programs

Version 4

• Added Extra lab codes
• Added lab to repo mapping

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Contribution

This repo is open for contributions. Please open an Issue or open a PR with appropriate edits.