Semester
Subject
Year
Tribhuwan University
Institute of Science and Technology
2075
Bachelor Level / Third Year / Sixth Semester / Science
B.Sc in Computer Science and Information Technology (CSC376)
(Compiler Design and Construction)
Full Marks: 60
Pass Marks: 24
Time: 3 Hours
Candidates are required to give their answers in their own words as for as practicable.
The figures in the margin indicate full marks.
Section A
Long Answers Questions
Attempt any TWO questions.
[2*10=20]
1.
Difference between compiler and interpreter. "Symbol table is necessary component of compiler". Justify this statement with examples.[6]
2.
List out the major tasks carried out in Lexical Analysis Phase. Convert the following NFA to DFA.
[6]
3.
Differentiate between recursive descent and non-recursive predictive parsing method. Find first and follow of all the non-terminals in the following grammar.
$E \rightarrow TA; A \rightarrow +TA|\varepsilon; T \rightarrow FB; B \rightarrow *FB|\varepsilon; F \rightarrow (E)|id$
[6]
$E \rightarrow TA; A \rightarrow +TA|\varepsilon; T \rightarrow FB; B \rightarrow *FB|\varepsilon; F \rightarrow (E)|id$
4.
Construct SLR parse table for the following grammar
$S \rightarrow E$
$E \rightarrow E+T|T$
$T \rightarrow T*F|F$
$F \rightarrow id$[6]
$S \rightarrow E$
$E \rightarrow E+T|T$
$T \rightarrow T*F|F$
$F \rightarrow id$
5.
Define Syntax directed definition. Construct annotated parse tree for the input expression (5*3+2)*5 according to the following syntax directed definition.
$\[\begin{array}{|l|l|}\hline \text{Production} & \text{Semantic Rule} \\ \hline L \to E\text{n} & \text{Print } E.\text{val} \\ \hline E \to E_1 + T & E.\text{val} \to E_1.\text{val} + T.\text{val} \\ \hline E \to T & E.\text{val} \to T.\text{val} \\ \hline T \to T_1 * F & T.\text{val} \to T_1.\text{val} * F.\text{val} \\ \hline T \to F & T.\text{val} \to F.\text{val} \\ \hline F \to (E) & F.\text{val} \to (E.\text{val}) \\ \hline F \to \text{digit} & F.\text{val} \to \text{digit.lexval} \\ \hline \end{array}\]$
[6]
$\[\begin{array}{|l|l|}\hline \text{Production} & \text{Semantic Rule} \\ \hline L \to E\text{n} & \text{Print } E.\text{val} \\ \hline E \to E_1 + T & E.\text{val} \to E_1.\text{val} + T.\text{val} \\ \hline E \to T & E.\text{val} \to T.\text{val} \\ \hline T \to T_1 * F & T.\text{val} \to T_1.\text{val} * F.\text{val} \\ \hline T \to F & T.\text{val} \to F.\text{val} \\ \hline F \to (E) & F.\text{val} \to (E.\text{val}) \\ \hline F \to \text{digit} & F.\text{val} \to \text{digit.lexval} \\ \hline \end{array}\]$
6.
Differentiate between static and dynamic type checking. How can we carry out type checking for the following expression using syntax-directed definition?
$S \rightarrow id = E$
$S \rightarrow if E then S1$
$S \rightarrow while E do S1$
$S \rightarrow S1; S2$[6]
$S \rightarrow id = E$
$S \rightarrow if E then S1$
$S \rightarrow while E do S1$
$S \rightarrow S1; S2$
7.
Define three address codes. write three address codes for
$S = do m = n + p while a < = b$[6]
$S = do m = n + p while a < = b$
8.
Define code optimization. Discuss about any three code optimization techniques with example.[6]
9.
What is activation record? Discuss the different activities performed by caller and callee during procedure call and return.[6]
10.
Discuss about the different factors affecting target code generation.[6]