Code Generation Questions

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1.

Code generation can be considered as the?

A

first phase of compilation

B

second phase of compilation

C

third phase of compilation

D

final phase of compilation

Correct Answer: D

Code generation can be considered as the final phase of compilation.

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2.

 ___________ is a tool that depicts the structure of basic blocks, helps to see the flow of values flowing among the basic blocks, and offers optimization too.

A

DAG

B

CAG

C

SAG

D

PAG

Correct Answer: A

Directed Acyclic Graph (DAG) is a tool that depicts the structure of basic blocks, helps to see the flow of values flowing among the basic blocks, and offers optimization too.

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3.

n Directed Acyclic Graph, Leaf nodes represent?

A

identifiers

B

names 

C

constants

D

All of the above

Correct Answer: D

Leaf nodes represent identifiers, names or constants.

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4.

n Algebraic expression simplification, a = a + 1 can simply be replaced by?

A

a

B

INC a

C

DEC a

D

MUL a

Correct Answer: B

the expression a = a + 0 can be replaced by a itself and the expression a = a + 1 can simply be replaced by INC a.

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5.

x * 2 can be replaced by x << 1 is an example of?

A

Algebraic expression simplification

B

Accessing machine instructions

C

Strength reduction

D

Code Generator

Correct Answer: C

Strength reduction : There are operations that consume more time and space. Their

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6.

 The following code is an example of?

void add_ten(int x)
{
   return x + 10;
   printf(""value of x is %d"", x);
}

A

Redundant instruction elimination

B

Unreachable code

C

Flow of control optimization

D

None of the above

Correct Answer: B

Unreachable code : Unreachable code is a part of the program code that is never accessed because of programming constructs.

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7.

How many descriptors are used for track both the registers (for availability) and addresses (location of values) while generating the code?

A

2

B

3

C

4

D

5

Correct Answer: A

The code generator has to track both the registers (for availability) and addresses (location of values) while generating the code. For both of them, the following two descriptors are used: Register descriptor and Address descriptor

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8.

__________ are used to keep track of memory locations where the values of identifiers are stored.

A

Register descriptor

B

Address descriptor

C

Both A and B

D

None of the above

Correct Answer: B

Address descriptor : Values of the names (identifiers) used in the program might be stored at different locations while in execution. Address descriptors are used to keep track of memory locations where the values of identifiers are stored.

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9.

Code generator uses ______ function to determine the status of available registers and the location of name values.

A

setReg

B

cinReg

C

pfReg

D

getReg

Correct Answer: D

Code generator uses getReg function to determine the status of available registers and the location of name values.

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10.

Which of the following is not a form of Intermediate representation?

A

Abstract Syntax Tree

B

3-address code

C

Directed cyclic Graph

D

Reverse Polish Notation

Correct Answer: C

IR Type : Intermediate representation has various forms. It can be in Abstract Syntax Tree (AST) structure, Reverse Polish Notation, or 3-address code.

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