1. What is the main goal of register allocation in code generation?
A) To minimize the number of instructions
B) To assign variables to machine registers efficiently
C) To optimize the high-level language code
D) To detect runtime errors
Answer: B) To assign variables to machine registers efficiently
2. Which of the following is a common technique used for register allocation?
A) Linear scan
B) Syntax analysis
C) Code optimization
D) Loop unrolling
Answer: A) Linear scan
3. Which of the following factors affects the register allocation process?
A) The number of available registers in the target machine
B) The syntax of the high-level language
C) The number of instructions in the intermediate code
D) The type of compiler being used
Answer: A) The number of available registers in the target machine
4. What does “register spilling” refer to in register allocation?
A) Storing values in registers that are not needed
B) Moving data from registers to memory when there are not enough registers
C) Removing unnecessary instructions
D) Allocating more registers than required
Answer: B) Moving data from registers to memory when there are not enough registers
5. What is the primary task of a register allocator in a compiler?
A) Assign values to specific memory locations
B) Ensure that variables are only accessed through registers
C) Allocate variables to CPU registers and manage their lifetimes
D) Generate machine-specific assembly code
Answer: C) Allocate variables to CPU registers and manage their lifetimes
6. Which of the following is a common approach to register assignment?
A) Graph coloring
B) Syntax tree traversal
C) Loop invariant code motion
D) Constant folding
Answer: A) Graph coloring
7. What is a “live range” in the context of register allocation?
A) The amount of time a variable is used in the program
B) The number of instructions a variable is involved in
C) The period during which a variable is stored in a register
D) The maximum number of registers available
Answer: C) The period during which a variable is stored in a register
8. Why is register allocation important in compiler design?
A) To ensure that the program adheres to the target languageās syntax
B) To optimize the execution of a program by minimizing memory access
C) To detect errors in the code
D) To generate intermediate code efficiently
Answer: B) To optimize the execution of a program by minimizing memory access
9. Which of the following is an example of a situation where register spilling occurs?
A) When the number of registers available exceeds the number of variables
B) When multiple variables need to be assigned to the same register
C) When the number of live variables exceeds the number of available registers
D) When a variable is not used during the execution of the program
Answer: C) When the number of live variables exceeds the number of available registers
10. In a graph coloring approach to register allocation, what does each node represent?
A) An instruction in the intermediate code
B) A variable or a register
C) A memory address
D) A function call
Answer: B) A variable or a register
11. What is the purpose of interference graphs in register allocation?
A) To track the locations of variables in memory
B) To represent the relationships between variables that cannot share the same register
C) To optimize instruction selection
D) To optimize code execution time
Answer: B) To represent the relationships between variables that cannot share the same register
12. Which of the following is a disadvantage of register spilling?
A) It increases the execution time due to memory accesses
B) It reduces the number of registers available
C) It simplifies the code generation phase
D) It improves the program’s memory access speed
Answer: A) It increases the execution time due to memory accesses
13. Which of the following is an example of a register allocation algorithm?
A) Mark-and-sweep algorithm
B) The Chaitin-Briggs algorithm
C) Dynamic programming algorithm
D) Depth-first search algorithm
Answer: B) The Chaitin-Briggs algorithm
14. What is the impact of a poor register allocation strategy?
A) The program will have improved performance
B) The program will use more memory and experience slower execution
C) The code will be simpler and easier to understand
D) The program will have fewer errors
Answer: B) The program will use more memory and experience slower execution
15. What does “coalescing” mean in the context of register assignment?
A) Combining variables into fewer registers to optimize register usage
B) Splitting variables into multiple registers to reduce spilling
C) Assigning variables to registers that are not live
D) Removing unnecessary registers from the code
Answer: A) Combining variables into fewer registers to optimize register usage