Activation records and call stack in Compiler Design - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding the purpose of activation records

What is the main purpose of an activation record in the context of function calls?

A To manage the input/output operations of a program

B To hold the compiled machine code of a function

C To store information about a function call such as parameters, local variables, and return address

D To keep track of global variables across the entire program

💡 Hint

Think about what information a program needs to remember when it calls a function and later returns.

An activation record stores all the necessary information for a single function call, including parameters, local variables, and where to return after the function finishes.

📋 Factual

intermediate

Call stack behavior during nested function calls

Consider three functions: main calls funcA, which calls funcB. How does the call stack change during these calls?

A The call stack replaces the activation record of <strong>main</strong> with <strong>funcA</strong>, then replaces <strong>funcA</strong> with <strong>funcB</strong>

B The call stack remains empty until <strong>funcB</strong> is called

C The call stack grows by adding activation records for <strong>funcB</strong>, then <strong>funcA</strong>, then <strong>main</strong>

D The call stack grows by adding activation records for <strong>main</strong>, then <strong>funcA</strong>, then <strong>funcB</strong> in that order

💡 Hint

Remember that each function call adds a new activation record on top of the stack.

When functions call other functions, each call adds a new activation record on top of the call stack, preserving the order of calls.

🔍 Analysis

advanced

Identifying the return address in an activation record

Which part of an activation record is responsible for telling the program where to continue execution after a function returns?

A Return address field

B Local variables section

C Parameter list

D Saved frame pointer

💡 Hint

Think about what the program needs to know to resume after finishing a function.

The return address field stores the location in the code where execution should continue after the function call completes.

❓ Comparison

advanced

Difference between static and dynamic links in activation records

What is the key difference between static links and dynamic links stored in activation records?

A Static links are used only in recursive calls, dynamic links are used in iterative calls

B Static links point to the activation record of the lexically enclosing function, dynamic links point to the caller's activation record

C Static links store local variables, dynamic links store parameters

D Static links point to the caller's activation record, dynamic links point to the lexically enclosing function

💡 Hint

Consider the difference between lexical scope and call history.

Static links help access variables in the surrounding code blocks (lexical scope), while dynamic links help return control to the caller function.

❓ Reasoning

expert

Effect of missing dynamic link on program execution

What would most likely happen if an activation record did not store a dynamic link during a function call?

A The program would fail to return correctly to the caller, causing incorrect execution flow or crash

B The function would not be able to access its local variables

C The program would run normally without any issues

D The function parameters would be lost during the call

💡 Hint

Think about how the program knows where to go after a function finishes.

Without the dynamic link, the program cannot find the caller's activation record to return control, leading to incorrect execution or crash.