Compilers Explained

Parsing Techniques

• Recursive Descent: A top-down parsing method where each grammar rule is implemented by a function. It is intuitive but may struggle with left recursion.
• LL(1) Parsing: A predictive parsing technique using one lookahead token to decide which production to use. Efficient for many programming languages with suitable grammar.
• SLR Parsing: A bottom-up parsing approach using Simple LR(1) automata. It handles a broader class of grammars than LL(1), suitable for more complex languages.

Runtime Stack & Activation Records

The runtime stack manages function calls and local variables during program execution. Each function call creates an activation record (or stack frame) that stores:

• Return address
• Parameters passed to the function
• Local variables
• Saved registers

Offsets are used within activation records to access these elements relative to the stack pointer or frame pointer, enabling efficient memory addressing during runtime.