Compiler MCQ with Answers Set-1

This post contains a computer network related to 20 multiple-choice questions (compiler SET-1) that help you to go through the subject and prepare you for compiler related questions in a competitive exam.

Compiler MCQ Test Series Set-1

Total Number of Questions: 20
Each question carries equal marks i.e 1
No Negative Marking

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1. Relocation bits used by relocating loader are specified (generated) by

A.Relocatingloader itself

B.Linker

C.Assembler or Translator

D.Macro processor

E.None of These

2. Which one of the following kinds of derivation is used by LR parsers?

A.Leftmost

B.Leftmost in reverse

C.Rightmost

D.Rightmost in reverse

3. Consider the following statements.

$S_1$: The sequence of procedure calls corresponds to a preorder traversal of the activation tree.

$S_2$: The sequence of procedure returns corresponds to a postorder traversal of the activation tree.

Which one of the following options is correct?

A.$S_1$ is true and $S_2$ is false

B.$S_1$ is false and $S_2$ is true

C.$S_1$ is true and $S_2$ is true

D.$S_1$ is false and $S_2$ is false

4. Consider the following statements.

$S_1$: Every SLR(1) grammar is unambiguous but there are certain ambiguous grammars that are not SLR(1).

$S_2$: For any context-free grammar, there is a parser that takes at a most time to parse a string of length n.

Which one of the following options is correct?

A.$S_1$ is true and $S_2$ is false

B.$S_1$ is false and $S_2$ is true

C.$S_1$ is true and $S_2$ is true

D.$S_1$ is false and $S_2$ is false

5. Consider the following statements.

The symbol table is accessed only during analysis and syntax analysis.
Compilers for programming languages that support recursion necessarily need heap storage for memory allocation in the run-time environment.
Errors violating the condition ‘any variable must be declared before its use’ are detected during syntax analysis.

Which of the above statements is/are TRUE?

A.1 only

B.2 only

C.Both 1 and 2

D.Neither 1 and 2

Consider the following grammar (That admits a series of declarations, followed by expressions) and the associated syntax-directed translation (SDT) actions, given as pseudo-code:

$P\rightarrow D^{\ast} E^{\ast}$

$D\rightarrow$ int ID { record that ID. lexeme is of type int }

$D\rightarrow$ bool ID (record that ID. lexeme is of type bool}

$E\rightarrow E_1+E_2\left \{ check that E_1.type = E_2.type = int ; set E.type :=int \right \}$

$E\rightarrow !E_1\left \{ check that E_1.type = bool ; set E.type :=bool \right \}$

$E\rightarrow ID\left \{set E.type :=int \right \}$

With respect to the above grammar, which one of the following choices is correct?

A.The actions can be used to correctly type-check any syntactically correct program.

B.The actions can be used to type-check syntactically correct integer variable declarations and integer expressions.

C.The actions can be used to type-check syntactically correct Boolean variable declarations and boolean expressions

D.The actions will lead to an infinite loop.

7. Consider the following context-free grammar where the set of terminals is {a, b, c, d, f}.

$S\rightarrow daT|Rf$

$T\rightarrow aS|baT|\varepsilon$

$R\rightarrow caTR|\varepsilon$

The following is a partially-filled LL(1) parsing table.

	a	b	c	d	f	$
S			(1)	$S\rightarrow daT$	(2)
T	$T\rightarrow aS$	$T\rightarrow baT$	(3)		$T\rightarrow \varepsilon$	(4)
R			$R\rightarrow caTR$		$R\rightarrow \varepsilon$

Which one of the following choices represents the correct combination for the numbered cells in the parsing table (“blank” denotes that the corresponding cell is empty)?

A.(1)$S\rightarrow Rf$ (2) $S\rightarrow Rf$ (3) $T\rightarrow \varepsilon$ (4)$T\rightarrow \varepsilon$

B.(1)blank (2) $S\rightarrow Rf$ (3) $T\rightarrow \varepsilon$ (4)$T\rightarrow \varepsilon$

C.(1)$S\rightarrow Rf$ (2) blank (3) blank (4)$T\rightarrow \varepsilon$

D.(1)blank (2) $S\rightarrow Rf$ (3) blank (4)blank

8. Cross-compiler is a compiler:

A.Which is written in a language that is different from the source language.

B.That generates object code for its host machine.

C.Which is written in a language that is same as the source language.

D.That runs on one machine but produces object code for another machine.

E.Both A and B

9. Consider the following language.

L=\left \{ w \varepsilon{0, 1}^{*}|w ends with the substring 011 \right \}

Which one of the following deterministic finite automata accepts L?

10. For a statement S in a program, in the context of liveness analysis, the following sets are defined :
USE(S): the set of variables used in S
IN(S): the set of variables that are live at the entry of S
OUT(S): the set of variables that are live at the exit of S
Consider a basic block that consists of two statements, S_1 followed by S_2. Which one of the following statements is correct?

A.$OUT(S_1) = IN(S_2)$

B.$OUT(S_1) = IN (S_1) \cup USE (S_1)$

C.$OUT(S_1) = IN (S_2) \cup OUT(S_2)$

D.$OUT(S_1) = USE(S_1) \cup IN(S_2)$

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11. For a Turing machine M, (M) denotes an encoding of M. Consider the following two languages.

Which one of the following options is correct?

$L_{1} = { < M> |M takes more than 2021 steps on all inputs } $

$L_{2} = { < M> |M takes more than 2021 steps on some input } $

Which one of the following options is correct?

A.Both $L_{1}$ and $L_{2}$ are decidable

B.$L_{1}$ is decidable and {L_(2)} is undecidable

C.$L_{1}$ is undecidable and {L_(2)} is decidable

D.Both $L_{1}$ and $L_{2}$ are undecidable

12.

Consider the productions Each of the five non-terminals A, P, Q, X, and Y has two attributes; s is a synthesized attribute, and i is an inherited attribute, Consider the following rules.

Rule 1 : P.i=A.i+2, Q.i+P.i+A.i, and A.s=P.s+Q.s

Rule 2: X.i=A.i+Y.s and Y.i=X.s+A.i

Which one of the following is TRUE?

A.Both Rule 1 and Rule 2 are I, -attributed.

B.Only Rule 1 is L-attributed.

C.Only Rule 2 is L-attributed.

D.Neither Rule nor Rule 2 is L-attributed.

13. In the context of compilers, which of the following is/are NOT an intermediate representation of the source program?

A.Three address code

B. Abstract Syntax Tree (AST)

C.Control Flow Graph (CFG)

D.Symbol Table

14.

Consider the following grammar and the semantic actions to support the inherited type declaration attributes. Let $x_{1},x_{2},x_{3},x_{4},x_{5}$ and $x_{6}$ be the placeholders for the non-terminals D, T, L or $L_{1}$ or in the following table:

Production rule	Semantic action
D→TL	$x_{1}$.type =$x_{2}$.type
T→int	T. type=int
T→float	T. type=float
L$\to L_{1}$, id	$x_{3}$.type =$x_{4}$.type addType (id. entry,$x_{5}$.type )
L→id	addType (id. entry, $x_{6}$.type)

Which one of the following are the appropriate choices for $x_{1},x_{2},x_{3},x_{4}$?

A.$x_{1}=L ,x_{2}= T,x_{3}= L_{1},x_{4} = L$

B.$x_{1}=T ,x_{2}= L,x_{3}= L_{1},x_{4} = T$

C.$x_{1}=L ,x_{2}= L,x_{3}= L_{1},x_{4} = T$

D.$x_{1}=T ,x_{2}= L,x_{3}= T,x_{4} = L_{1}$

15. Compiler is preferred over interpreter because

A.It can generate stand-alone programs that often take less time for execution

B.It is much helpful in the initial stages of program development

C.Debugging can be faster and easier

D.If one changes a statement, only that statement needs recompilation

E.It needs less computer resources

16. A bottom-up parser generates

A.Right-most derivation

B.Right-most derivation in reverse

C.Left-most derivation

D.Left-most derivation in reverse

E.Both Right-most derivation and Left-most derivation possible

17.

Consider the grammar given below:

$S\to Aa$

$A\to BD$

$B\to b|\in $

$D\to d|\in $

Let a, b, d, and $ be indexed as follows:

a	b	d	$
3	2	1	0

Compute the FOLLOW set of the non-terminal B and write the index values for the symbols in the FOLLOW set in the descending order. (For example, if the FOLLOW set is (a, b, d, $}, then the answer should be 3210).

A.31

B.30

C.29

D.28

18.

Consider the following grammar.

$S\to aSB|d$

$B\to b

The number of reduction steps taken by a bottom-up parser while accepting the string aaadbbb is

A.4

B.5

C.6

D.7

19. Consider the following C code segment:

a=b+c;

e=a+1;

d=b+c;

f=d+1:

g=e+f;

In a compiler, this code segment is represented internally as a directed acyclic graph (DAG). The number of nodes in the DAG is

A.6

B.7

C.5

D.8

20. Consider the following augmented grammar with {#, @, <, >, a,b,c} as the set of terminals.
S^'→S
S→S#cS
S→SS
S→S@
S→<S>
S→a
S→b
S→c
Let $I_0-CLOSURE ({→⦁S}).$ The number of items in the set $GOTO(GOTO(I_0,<)$ is_

A.10

B.12

C.8

D.16

Compiler MCQ Test Series Set-1

Total Number of Questions: 20

Each question carries equal marks i.e 1

No Negative Marking

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