1
An activation record stores
Correct Answer
information needed for a single execution of a procedure
☑ MCQ PRACTICE
Compiler Design Unit 4
Practice objective questions for quick revision and examination preparation. Try answering each question before revealing the answer.
Compiler Design MCQs - Unit 4
2
In stack allocation, activation records are
Correct Answer
pushed on a procedure call and popped on return
3
The control link in an activation record points to
Correct Answer
the activation record of the caller
4
The access link is used to
Correct Answer
reach nonlocal data under static scoping
5
A display is
Correct Answer
an array of pointers to activation records used for nonlocal access
6
The heap is used for
Correct Answer
dynamically allocated data whose lifetime is not tied to a procedure
7
A dangling pointer is a pointer to
Correct Answer
memory that has already been freed
8
A memory leak occurs when
Correct Answer
allocated memory is never freed and cannot be reached
9
Garbage collection is the automatic
Correct Answer
reclamation of memory that is no longer reachable
10
A weakness of reference counting is that it cannot reclaim
Correct Answer
cyclic garbage
11
Mark-and-sweep garbage collection first
Correct Answer
marks all reachable objects and then sweeps the unmarked ones
12
Trace-based collection starts from the
Correct Answer
root set
13
A basic block is a sequence of statements with
Correct Answer
a single entry and a single exit
14
The first statement of a basic block is called a
Correct Answer
leader
15
In a flow graph, the nodes are
Correct Answer
basic blocks
16
A DAG for a basic block helps in
Correct Answer
eliminating common subexpressions
17
Peephole optimization examines
Correct Answer
a small window of target instructions
18
Which of the following is a peephole optimization?
Correct Answer
Eliminating redundant loads and stores
19
Register allocation can be modelled using
Correct Answer
graph coloring
20
Which of the following is an issue in the design of a code generator?
Correct Answer
Instruction selection
21
Replacing x * 2 by x + x is an example of
Correct Answer
strength reduction
22
Replacing x + 0 by x is an example of
Correct Answer
algebraic simplification
23
Dynamic programming code generation is used to generate optimal code for
Correct Answer
expression trees
24
The input to the code generator is the intermediate representation together with
Correct Answer
the symbol table
25
In a stack-based environment, local variables are accessed relative to
Correct Answer
the frame (stack) pointer
Fill in the Blanks
26
An ______ record stores the information needed for one execution of a procedure.
Correct Answer
activation
27
The ______ link in an activation record points to the caller's activation record.
Correct Answer
control
28
The ______ link is used to access nonlocal data under static scoping.
Correct Answer
access
29
Dynamically allocated data with an unknown lifetime is stored in the ______.
Correct Answer
heap
30
A pointer to memory that has already been freed is called a ______ pointer.
Correct Answer
dangling
31
Reference counting cannot reclaim ______ structures.
Correct Answer
cyclic
32
Mark-and-sweep garbage collection has two phases: mark and ______.
Correct Answer
sweep
33
A basic block has a single entry and a single ______.
Correct Answer
exit
34
The first statement of a basic block is called a ______.
Correct Answer
leader
35
In a flow graph, the nodes are ______.
Correct Answer
basic blocks
36
Peephole optimization examines a small ______ of instructions.
Correct Answer
window
37
Strength reduction replaces expensive operations with ______ ones.
Correct Answer
cheaper
38
Register allocation can be done using graph ______.
Correct Answer
coloring
39
A DAG helps in common ______ elimination within a basic block.
Correct Answer
subexpression
40
Replacing x * 8 with x << 3 is an example of ______ reduction.
Correct Answer
strength