’

JE – 838

*JE8338*

VIII Semester B.E. (CSE/ISE) Degree Examination, June/July 2013 (2K6 Scheme) CI – 8.2/IS – 8.4.1 : COMPILER DESIGN Time : 3 Hours

Max. Marks : 100

Instruction : Answer any five full questions, selecting atleast two from each Part. PART – A 1. a) Explain the various phases of a compiler with a neat diagram.

12

b) What is the purpose of the transition diagram ? Construct a transition diagram for 1) Arithmetic operators 2) Identifiers.

8

2. a) Explain how left recursion and left factoring of a grammar is carried out for the following grammar

10

S → Aa | b A → Ac | Sd | ∈

b) What is Input Buffering ? Explain the methods of input buffering in a compiler. 3. a) Discuss the LR and LL parsers with the following grammar S → i SeS | iS | a

10 10

b) Explain the stack implementation of shift reduce passing for the input id1 + id2 + id3 and consider the grammar E →E +E E →E*E E → (E) / id

10

P.T.O.

*JE838*

JE – 838

4. a) Generate LR parsing table for the following grammar and find whether the grammar is ambiguous or not.

12

S → AS S→b A → SA A→a

b) Explain with examples synthesized attributes and Inherited attributes.

8

PART – B 5. a) Briefly explain the different types of intermediate codes, with the example expression a : = b * – c + b * – c. b) Explain in detail various issues involved in code generation.

12 8

6. a) Explain how the run-time memory is divided into different data areas. What are the various allocation strategies used for respective data types ? 10 b) Explain the hash table implementation used for symbol tables.

10

7. a) What do you mean by machine independent code optimization ? Explain various code optimization methods. b) Explain the various strategies used for register allocation and assignment.

10 10

8. Write short notes on : i) Error recovery in LR parsers ii) Loops in flow graphs iii) Storage allocation strategies iv) Bottom-up evaluation of S-attributes.

—————————

(4×5=20)