20 Compiler Interview Questions and Answers

Compilers are an important part of the software development process, translating high-level programming languages into machine code that can be executed by a computer. As a result, compilers are complex pieces of software, and those who work with them need to have a strong understanding of both the theory and practice of compiler development.

If you’re interviewing for a position that involves compiler development, you can expect to be asked a number of questions about your knowledge and experience. In this article, we’ll go over some of the most common compiler interview questions and how you should answer them.

Compiler Interview Questions and Answers

Here are 20 commonly asked Compiler interview questions and answers to prepare you for your interview:

1. What is a compiler?

A compiler is a computer program that translates computer code written in one programming language into another programming language.

2. Can you explain what the front-end and back-end of a compiler are?

The front-end of a compiler is responsible for taking in the code that is to be compiled and turning it into an intermediate representation. The back-end of a compiler is then responsible for taking that intermediate representation and turning it into machine code that can be run on a computer.

3. What are some common tasks that compilers perform?

Some common tasks that compilers perform include:

– translating source code into machine code
– optimizing code for performance
– checking code for errors
– generating reports

4. What tools do you think are needed to build a compiler?

In order to build a compiler, you will need a few different tools. First, you will need a text editor in order to write the code for your compiler. Second, you will need a compiler compiler, which will take your code and turn it into an executable program. Finally, you will need a linker, which will take the object code generated by the compiler and link it together into a single program.

5. Why would anyone want to build their own compiler?

There are a few reasons someone might want to build their own compiler. Maybe they want to target a new or unusual platform, or want more control over the optimization of the generated code. In some cases, people build their own compilers as a learning exercise.

6. How does lexical analysis work in context with compiling source code?

In order for a compiler to understand source code, it first needs to be able to break it down into smaller, more manageable pieces. This is where lexical analysis comes in. Lexical analysis is the process of taking source code and breaking it down into smaller units called tokens. The compiler can then use these tokens to begin the process of actually compiling the code.

7. What are the different types of tokens recognized by most compilers?

The different types of tokens recognized by most compilers are:

1. Keywords: these are reserved words that have a specific meaning in the programming language and cannot be used as variable names, function names, etc.

2. Identifiers: these are names that are used to identify variables, functions, etc.

3. Literals: these are values that are hard-coded into the program, such as numbers or strings.

4. Operators: these are symbols that represent operations that can be performed on variables, such as +, -, *, /, etc.

8. What does it mean for a token to be “well formed”?

A well-formed token is a token that conforms to the rules of the language it is written in. For example, a well-formed token in Java would be a token that is correctly formatted according to the Java syntax rules.

9. Do all programming languages have parsers? If not, then why not?

All programming languages have parsers, but not all of them have compilers. A parser is a program that reads through code and breaks it down into smaller pieces in order to understand its structure. A compiler is a program that takes the output of a parser and turns it into machine code that can be run on a computer. Some languages, like Python, only have parsers because they don’t need to be compiled before they can be run.

10. How many passes does a typical compiler make when building an executable?

A typical compiler will make multiple passes when building an executable. The number of passes can vary depending on the complexity of the program being compiled, but a common number is four. The first pass is usually the lexical analysis, which breaks the program down into tokens. The second pass is the syntactic analysis, which checks the tokens for correctness. The third pass is the semantic analysis, which checks for meaning. The fourth and final pass is the code generation, which produces the actual executable code.

11. What is the purpose of the intermediate representation generated during compilation?

The purpose of the intermediate representation is to provide a platform-independent representation of the code that can be used by the compiler to generate the final code. This allows the compiler to be platform-independent and to generate code for multiple platforms from a single source.

12. What’s the difference between static, dynamic, and run time linking?

Static linking is when all of the required libraries are linked directly into the executable file. This means that the executable will be larger, but it will not need any external libraries to run. Dynamic linking is when the executable file only contains references to the required libraries, and those libraries are loaded at run time. This means that the executable will be smaller, but it will need the external libraries to be present in order to run. Run time linking is when the required libraries are linked into the executable file, but they are not loaded until they are needed at run time. This means that the executable will be larger, but it will only need the external libraries to be present when they are needed.

13. What are some examples of cases where runtime errors occur?

A runtime error can occur when a program tries to access a file that does not exist, tries to divide by zero, or tries to access an array outside of its bounds. These are just a few examples; there are many more potential cases where runtime errors can occur.

14. In which stages (front-end or back-end) of the compilation process can optimizations be made?

Optimizations can be made in both the front-end and back-end of the compilation process. In the front-end, the compiler can optimize the code for better performance by reducing the number of instructions needed to execute the code. In the back-end, the compiler can optimize the code for better memory usage by reducing the amount of memory needed to store the code.

15. Which one is faster: interpreted code or compiled code?

There is no simple answer to this question, as it depends on a number of factors. In general, compiled code will be faster than interpreted code, because it has already been translated into machine code that the computer can execute directly. However, interpreted code can sometimes be faster to execute, because it does not need to be compiled before it is run.

16. When using a compiler, how would you go about handling exceptions?

When using a compiler, you would need to use a try/catch block in order to handle exceptions. This would allow you to catch any errors that might occur during the compilation process and take appropriate action.

17. How do you handle memory allocation and deallocation while using a compiler?

Memory allocation and deallocation is a key concern when working with a compiler. When allocating memory, you need to ensure that there is enough space for all the data that needs to be stored. This can be a challenge, especially if you are working with large data sets. Deallocation is also important, as you need to make sure that you free up memory when you are finished with it. This can be tricky, as you need to make sure that you do not accidentally deallocate memory that is still in use.

18. Is it possible to compile multiple files at once? If yes, then how?

Yes, it is possible to compile multiple files at once using a compiler. This can be done by passing the compiler a list of files to compile, or by using a wildcard character to compile all files in a directory.

19. Can you give me some examples of popular compilers used today?

Some popular compilers used today include the GNU Compiler Collection (GCC), Clang, and Microsoft Visual C++.

20. What are the main rules that govern scope resolution in C++?

The main rules that govern scope resolution in C++ are the following:

-The scope of a name declared in a block is the entire block in which it is declared, from the point of declaration to the end of the block.

-The scope of a name declared in a function is the entire function in which it is declared, from the point of declaration to the end of the function.

-The scope of a name declared in a class is the entire class in which it is declared, from the point of declaration to the end of the class.