Compiler Design Test 1

Question 1
2 / -0.33

Consider the following syntax directed definition:
Production
Semantic Rule
T → FT’
T’.val = F.val
T’ → * FT’₁
T’.val = T’₁.val * F.val

The above SDD is

A
Synthesized

B
Inherited

C
S – attributed

D
L – attributed

Question 2
2 / -0.33

Consider the following grammar where capital letter is non-terminal and smaller letter are terminal
X → P Q R | y z Q | Q x | Q
P → ax | PQ
Q → b | ϵ
R → c | ϵ
What is the number of terminals in the FIRST of X?
(if epsilon is present include it)

A
5-5

B
54-51

C
57-56

D
59-52

Question 3
2 / -0.33

What will be the result of following code after constant propagation?
int x =4;
int y = x * 2;
int z = a[y];

A
int x = 4;
int y = 4 * 2;int z = a[y];

B
int y =4 *2;int z = a[y]

C
int y = 8;
int z = a[y];

D
int z = a[8];

Question 4
2 / -0.33

Consider the grammar given below
E → TE’
E' → +TE' | ϵ
T → FT'
T' → *FT' | ϵ
F → (E) | id
Which of the following terminal symbol will be present in FOLLOW(F)?

A
+

B
*

C
)

D
$

Question 5
2 / -0.33

Match all items in Group 1 correct option from those given in Group 2.
Group 1
Group 2
P. Intermediate representation
1. Activation records
Q. Top-down parsing
2. Code generation
R. Runtime environments
3. Leftmost derivation
S. Register allocation
4. Graph coloring

A
P – 2, Q – 3, R – 4, S – 1

B
P – 1, Q – 2, R – 3, S – 4

C
P – 4, Q – 2, R – 3, S – 1

D
P – 2, Q – 3, R – 1, S – 4

Question 6
2 / -0.33

The number of tokens in the following C statement is
int i = 10;
float b = 12.0;
printf("x = %i, y = %f", i++, ++b);

A
21-21

B
214-211

C
217-216

D
219-212

Question 7
2 / -0.33

Find the Left factoring of a grammar
S → iEtS | iEtSeS | a
E → b

A
S → iEtS’ | a
S’ → eS| ∈
E → b

B
S → iEtSS’ | a
S’ → eS | ∈
E → b

C
S → iEtSS’ | a
S’ → eS
E → b

D
S → iEtS’|a
S’ → eS’’|∈
S’’ → a
E → b

Question 8
2 / -0.33

Consider the following grammar:
S → aS'
S' → aS' | ϵ
Which of the following is/are true for the above grammar?

A
not left recursive

B
ambiguous

C
LL(1)

D
FIRST(S) = {a, ϵ}

Question 9
2 / -0.33

Consider the following code segment:
p = q – r
s = r + t
p = s + p
s = a + s
What it the minimum number of total variables required to convert the above code segment to static single assignment?

A
8-8

B
84-81

C
87-86

D
89-82

Question 10
2 / -0.33

Look at the below given code in C – program.
int main()
{
int i = 10;
whlie(i--)
printf(“TESTBOOK\n”);
}
Identity the compiler’s response about the above given code while creating the object- module

A
Prints TESTBOOK 10 times

B
Prints TESTBOOK 9 times

C
Lexical Error

D
Syntactic Error

Question 11
2 / -0.33

Consider the below given grammar
S → L | M
L → c | b
M → b | a
where S is the start symbol also S, L, and M are non-terminal while x, y, z is terminal symbol.
Consider the predictive parsing table find the production for R1 and R2 respectively

a
b
c
$
S
S → M
R1
S → L

L

L → b
R2

M
M → a
B → b

A
R1 = {S → L} and R2 = {L → c}

B
R1 = {S → M} and R2 = {L → c}

C
R1 = {S → L and S → M} and R2 = {L → c}

D
R1 = {S → L and S → M} and R2 = {M → c}

Question 12
2 / -0.33

Which of the following statement about peephole optimization is/are correct?

A
It is done by examining a sliding window of target instructions and replacing sequences within the peephole by shorter sequence possible.

B
Code in the peephole must be contiguous

C
It helps in strength reduction.

D
It eliminates the unreachable code.

Question 13
2 / -0.33

Consider the following grammar:
S → pAS | r
A → q
Find the number of reduction steps taken by a bottom-up parser while accepting the string "pqpqpqpqr"?

A
9-9

B
94-91

C
97-96

D
99-92

Question 14
2 / -0.33

Consider the following statements, which of the following is/are TRUE?

A
During a program execution, stack is used for dynamic memory allocation and heap is used for static memory allocation.

B
During a program execution, heap is stored in main memory and stack is present in secondary memory.

C
During a program execution, access to heap memory variable is slower as compared to accessing variables allocated on stack.

D
During a program execution, in multithreaded situation, each thread has its own stack and share a common heap memory.

Question 15
2 / -0.33

Consider the following statements in the C language –
for( i = 7 ; i ≤ 923 ; i++ )
{
      x = a + b × c;
}
Here, 3 address code for the above code is given.
1000: i=7
1001: if i ≤ 923 goto   P
1002: goto Q
1003: t₁ = b × c
1004: t₂ = a + t₁
1005: x = t₂
1006: i = i + 1
1007: goto   R
1008: end
Find the value of P, Q and R in the given 3 address code.

A
P = 1003 and Q = 1008

B
Q = 1000 and R = 1001

C
R = 1003 and Q = 1008

D
Q = 1008 and R = 1001

Question 16
2 / -0.33

Consider the following grammar and the semantic actions to support the L-attributed declaration attributes. Let A₁, A₂, A₃, A₄, A₅be the placeholders for the non- terminals S, X, Y or Z in the following table:
Production rule
Semantic action
S → X Y
A₁.val = A₂.val
X.val → +
Y.val = +
X.val → -
Y.val = -
Y → Z,id
A₃.val = A₄.val
Z → id
addType(id.entry, A₅.val)

Which one of the following is the appropriate choices for A₁, A₂, A₃, A_4,and A₅?

A
A4 = Y, A2 = Y, A3 = Z, A1 = X

B
A1 = X, A2 = Y, A3 = Y, A4 = Z

C
A1 = Y, A2 = X, A3 = Z, A4 = Y

D
A1 = S, A2 = Y, A3 = Z, A4 = Y

Submit Test

Production	Semantic Rule
T → FT’	T’.val = F.val
T’ → * FT’₁	T’.val = T’₁.val * F.val

Group 1	Group 2
P. Intermediate representation	1. Activation records
Q. Top-down parsing	2. Code generation
R. Runtime environments	3. Leftmost derivation
S. Register allocation	4. Graph coloring

Production rule	Semantic action
S → X Y	A₁.val = A₂.val
X.val → +	Y.val = +
X.val → -	Y.val = -
Y → Z,id	A₃.val = A₄.val
Z → id	addType(id.entry, A₅.val)

Compiler Design...

Question 1

Synthesized

Inherited

S – attributed

L – attributed

Question 2

5-5

54-51

57-56

59-52

Question 3

int x = 4;int y = 4 * 2;int z = a[y];

int y =4 *2;int z = a[y]

int y = 8;int z = a[y];

int z = a[8];

Question 4

+

*

)

$

Question 5

P – 2, Q – 3, R – 4, S – 1

P – 1, Q – 2, R – 3, S – 4

P – 4, Q – 2, R – 3, S – 1

P – 2, Q – 3, R – 1, S – 4

Question 6

21-21

214-211

217-216

219-212

Question 7

S → iEtS’ | aS’ → eS| ∈E → b

S → iEtSS’ | aS’ → eS | ∈E → b

S → iEtSS’ | aS’ → eSE → b

S → iEtS’|aS’ → eS’’|∈S’’ → aE → b

Question 8

not left recursive

ambiguous

LL(1)

FIRST(S) = {a, ϵ}

Question 9

8-8

84-81

87-86

89-82

Question 10

Prints TESTBOOK 10 times

Prints TESTBOOK 9 times

Lexical Error

Syntactic Error

Question 11

R1 = {S → L} and R2 = {L → c}

R1 = {S → M} and R2 = {L → c}

R1 = {S → L and S → M} and R2 = {L → c}

R1 = {S → L and S → M} and R2 = {M → c}

Question 12

It is done by examining a sliding window of target instructions and replacing sequences within the peephole by shorter sequence possible.

Code in the peephole must be contiguous

It helps in strength reduction.

It eliminates the unreachable code.

Question 13

9-9

94-91

97-96

99-92

Question 14

During a program execution, stack is used for dynamic memory allocation and heap is used for static memory allocation.

During a program execution, heap is stored in main memory and stack is present in secondary memory.

During a program execution, access to heap memory variable is slower as compared to accessing variables allocated on stack.

During a program execution, in multithreaded situation, each thread has its own stack and share a common heap memory.

Question 15

P = 1003 and Q = 1008

Q = 1000 and R = 1001

R = 1003 and Q = 1008

Q = 1008 and R = 1001

Question 16

A4 = Y, A2 = Y, A3 = Z, A1 = X

A1 = X, A2 = Y, A3 = Y, A4 = Z

A1 = Y, A2 = X, A3 = Z, A4 = Y

int x = 4;
int y = 4 * 2;int z = a[y];

int y = 8;
int z = a[y];

S → iEtS’ | a
S’ → eS| ∈
E → b

S → iEtSS’ | a
S’ → eS | ∈
E → b

S → iEtSS’ | a
S’ → eS
E → b

S → iEtS’|a
S’ → eS’’|∈
S’’ → a
E → b