Compiler Design · End Term · May 2026 · FN

Compiler Design · End Term · May 2026 FN

Questions and published explanations below are available without starting a test. Some questions may not have a published solution yet.

0 / 21 published solutions

Question 2 MCQ · 2.0 marks

A programmer writes an expression with mismatched grouping:

. Which compiler phase detects the missing closing parenthesis?

6406537461773.

Lexical Analyzer

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Syntax Analyzer (Parser)

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Semantic Analyzer

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Code Optimizer

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Question 3 MCQ · 2.0 marks

Why does the Static Single Assignment (SSA) form simplify compiler optimization and dataflow analysis?

6406537461777.

It gives each definition a unique SSA name so that every SSA name has exactly one static definition, simplifying def-use chains.

6406537461778.

It converts non-deterministic context-free grammars into deterministic parsing tables.

6406537461779.

It directly maps high-level syntax into binary machine code without an assembler.

6406537461780.

It automatically executes hot code blocks dynamically at runtime.

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Question 4 MCQ · 2.0 marks

Why do bottom-up LR parser generators (like Bison) handle left-recursive grammar rules efficiently, whereas predictive top-down LL(1) parsers cannot parse them directly?

6406537461793.

LR parsers shift input symbols and reduce recognized handles rather than recursively expanding the leftmost nonterminal, so left recursion does not cause infinite recursive expansion.

6406537461794.

LR parsers convert left recursion to right recursion at compile time.

6406537461795.

Top-down parsers use state-splitting algorithms that eliminate shift actions.

6406537461796.

LR parsers construct leftmost derivations.

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Question 5 MCQ · 2.0 marks

Consider the semantic rules associated with production

: •

•

Which classification accurately describes this Syntax-Directed Definition (SDD)?

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It is an S-attributed definition because

is synthesized.

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It is an L-attributed definition because inherited attributes depend only on parent attributes and left-sibling attributes.

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It is not L-attributed because

depends on multiple preceding siblings.

6406537461800.

It contains a cyclic dependency preventing evaluation.

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Question 6 MCQ · 2.0 marks

A compiler permits implicit widening (

) but reports semantic errors for implicit narrowing conversions (

). Given functions

and variables

, which function call compiles without semantic errors?

6406537461801. Source diagram or notation

6406537461802. Source diagram or notation

6406537461803. Source diagram or notation

6406537461804. Source diagram or notation

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Question 7 MCQ · 2.0 marks

If a compiler designer removes the marker production

from

and parses

while attempting to create the symbol table upon reduction of

, what semantic- action/symbol-table problem occurs during parsing?

6406537461810.

The parser cannot perform any shift actions.

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The lexer stops emitting token codes.

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Identifiers encountered inside

attempt to enter their scope records into a symbol table that has not yet been initialized.

6406537461813.

All variable data sizes default to 0 bytes.

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Question 8 MCQ · 2.0 marks

In a

loop containing a

statement, what is the precise control-flow target address to which the

jump must be backpatched?

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The first instruction of the loop body

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The instruction marking the beginning of the condition evaluation

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The instruction immediately following the

condition (the loop exit).

6406537461817.

The start of the surrounding function activation block.

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Question 9 MCQ · 2.0 marks

During compilation of a function body, the compiler encounters a local variable declaration

inside an inner block, while a parameter named

exists at the function level. Which statement correctly describes how the symbol table handles this declaration?

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It emits a fatal redeclaration error because identifier

already exists in an enclosing table.

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It accepts the declaration into the current inner block table because redeclaration checks examine only the current local scope (

6406537461825.

It overwrites the parameter

in the function-level table.

6406537461826.

It automatically renames the variable to avoid shadowing.

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Question 10 MCQ · 2.0 marks

What is the defining structural invariant of Static Single Assignment (SSA) form?

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Every source variable can only be modified at runtime once during execution.

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Every SSA variable name has exactly one static definition in the intermediate representation.

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No conditional jumps or loop structures are permitted in the control flow graph.

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All variables are allocated exclusively to hardware registers.

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Question 11 MCQ · 2.0 marks

In Local Value Numbering (LVN), what value number is assigned to a copy statement

6406537461839. Source diagram or notation

is assigned the existing value number of

(

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A brand new, unique value number is generated for

6406537461841. Source diagram or notation

receives a value number only after an arithmetic operation is performed.

6406537461842.

The value number of

is reset to null.

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Question 12 NAT · 3.0 marks

A lexical analyzer uses standard Lex rules to tokenize an input stream. Code snippet

Input:

How many total tokens are produced by the lexical analyzer for this input?

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Question 13 NAT · 3.0 marks

Consider the following expression grammar:

How many derivation steps are required in the **rightmost derivation** of the string

from the start symbol E?

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Question 14 NAT · 3.0 marks

Consider the augmented grammar:

How many total

items are present in state

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Question 15 NAT · 3.0 marks

Consider the Boolean expression:

Using the standard syntax-directed translation with backpatching for Boolean expressions, assume that: • Each relational expression

generates two consecutive TAC instructions: 1. A conditional jump:

2. An unconditional jump:

• The

counter gives the address of the next generated instruction. • Initially,

. • The logical NOT operator

only swaps the

and

and does not generate additional instructions. At which instruction number is the conditional jump for the comparison

generated?

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Question 16 MSQ · 3.0 marks

Consider the Deterministic Finite Automaton (DFA)

where: •

•

The transition function δ is defined as:

Which of the following strings will be **accepted** by this DFA? (Select all that apply)

6406537461782. Source diagram or notation

6406537461783. Source diagram or notation

6406537461784. Source diagram or notation

6406537461785. Source diagram or notation

6406537461786. Source diagram or notation

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Question 17 MCQ · 3.0 marks

Consider the following standard expression grammar:

What is

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{ +, ), $ }

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{ *, +, $ }

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{ +, * }

6406537461791.

{ ), $ }

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Question 18 MCQ · 3.0 marks

Given pointer

of type

and integer

, where

. When translating the pointer arithmetic expression

, which TAC sequence correctly computes the resulting address?

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t1 = ptr * 8 t2 = t1 + k

6406537461807.

t1 = k * 8 t2 = ptr + t1

6406537461808.

t1 = ptr + k

6406537461809.

t1 = k + 8 t2 = ptr + t1

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Question 19 MCQ · 3.0 marks

Consider the Three-Address Code block:

Which of the following is the correct set of instruction leaders for basic block partitioning?

6406537461827. Source diagram or notation

6406537461828. Source diagram or notation

6406537461829. Source diagram or notation

6406537461830. Source diagram or notation

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Question 20 NAT · 2.0 marks

A compiler translates the expression

without optimization or common subexpression elimination. Each binary operation generates exactly one binary arithmetic TAC instruction. How many binary arithmetic TAC instructions are emitted?

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