Download AKTU B-Tech 6th Sem 2017-2018 ECS603 Compiler Design Question Paper

Printed Pages: 02

Paper Id: 110603

Roll No.

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Sub Code: ECS603

B. Tech.

(SEM VI) CARRY OVER THEORY EXAMINATION 2017-18

Time: 3 Hours

Compiler Design

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Total Marks: 100

Note: 1. Attempt all Sections. If require any missing data; then choose suitably.

2. Any special paper specific instruction.

SECTION A

1. Attempt all questions in brief. 2 x 10 = 20

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1. What is a translator?
2. Differentiate between a compiler and an assembler.
3. Discuss conversion of NFA into a DFA. Also give the algorithm used in this conversion.
4. Write down the short note on symbol table.
5. Describe Data structure for symbol table.

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6. What is mean by Activation record
7. What is postfix notations?
8. Define Three address Code
9. What are Quadruples?
10. What do you mean by regular expression?

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SECTION B

2. Attempt any three of the following: 10 x 3 = 30

1. Write down the regular expression for
   1. The set of all strings over {a,b} such that the fifth symbol from the right is a.
   2. The set of all strings over {a,b} such that every block of four consecutive symbols contain at least two zero.

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2. Construct the NFA for the regular expression a/abb/a*b* by using Thompson's construction methodology.
3. Eliminate left recursion from the following grammar
   S?AB, A?BS | b, B?SA|a
4. Discuss conversion of NFA into a DFA. Also give the algorithm used in this conversion.
5. Explain non-recursive predictive parsing. Consider the following grammar and construct the predictive parsing table
   

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   E?TE'
   E'?+TE' | €
   T?FT'
   T'?*FT' | €
   F?F*|a|b

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SECTION C

3. Attempt any one part of the following: 10 x 1 = 10

1. Give Operator-precedence parsing algorithm. Consider the following grammar and build up operator precedence table. Also parse the input string (id+(id*id))
   E?E+T|T
   T?T*F
   

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   F?(E) | id
2. For the grammar
   S?aAd | bBd | aBe | bAe
   A?f
   B?f
   

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   Construct LR(1) Parsing table. Also draw the LALR table from the derived LR(1) parsing table.

4. Attempt any one part of the following: 10 x 1 = 10

1. What is postfix notations? translate (C+D)*(E+Y) into postfix using syntax directed translation scheme (STDS)
2. Consider the following grammar E?E+E | E*E | (E) | id. construct the SLR parsing table and suggest your final parsing table.

5. Attempt any one part of the following: 10 x 1 = 10

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1. Explain logical phase error and syntactic phase error. Also suggest methods for recovery of error.
2. Generate three address code for C[A[I, j] ] = B[I ,j]+C[A[ I, j ] ]+D[ I + j) (You can assume any data for solving the question, if needed) Assuming that all array elements are integer. Let A and B a 10 X 20 array with low1 = low2 = 1.

6. Attempt any one part of the following: 10 x 1 = 10

1. Give the algorithm for the elimination of local and global common Sub expression. discuss the algorithm with the help of example also.
2. Consider the following three address code segments

   
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   PROD := 0
   I := 1
   T1 := 4*1
   T2 := addr(A)-4
   T3 := T2[T1]
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   T4 := addr(B)-4
   T5 := T4[T1]
   T6 := T3*T5
   PROD := PROD +T6
   If i<=20 goto (3) 

   1. Find the basic blocks and flow graph of above sequence.

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   2. Optimize the code sequence by applying function preserving transformation and loop optimization technique.

7. Attempt any one part of the following: 10 x 1 = 10

1. Write short note on
   1. Loop optimization
   2. Global data analysis

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2. Write short note on
   1. Direct acyclic graph
   2. YACC parser generator

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