Compiler Construction VO

Question 1

What is the usual general flow

Answer 1

Source program → compilation (errors) → Target program

Question 2

Classification

Answer 2

Single-pass, multi-pass, debugging or optimizing

Question 3

Optimization - test

Answer 3

compile the program first, then with optimization
result should be the same

Question 4

Concept of compilation - Phases

Answer 4

Splitting into two phases

1 ANALYSIS: split into tokens and then generate intemediate code (code from which you can extract information)
2 SYNTHESIS: close to the machine, uses the intermediate code to generate the target program

resuable: e.g. nalysis phase remains the same, can be reused

Question 5

Analysis - overview

Answer 5

hierarchical structures (trees) storing syntactical information that comes from the source program
used also for: structure editors, pretty printers, static checkers, web browser, interpreters, …

Question 5

Analysis - flow

Answer 5

skeletal source program → preprocessor → source program → [compiler → target assembly language → assembler → relocatable machine code

after that (by the operating system):

relocatable machine code → loader/linker-editor → absolute machine code

Question 6

components of a compiler

Answer 6

source code

lexical analyzer
syntax analyzer
semantic analyzer
intermediate code generator
code optimizer
code generator

target code

Question 7

lexical analysis

Answer 7

sequence of characters are converted to tokens

Tokens:

identifier
assignment symbols
operators
…

Question 8

Syntax analysis

Answer 8

grammatical analysis
based on rules of grammar
taking tokens (based on symbols)

generating parse tree where we see how the derivation of the grammar rules is done

Question 9

Semantic analysis

Answer 9

check for semantic errors

type checking

example: conversion between types

Question 10

intermediate code generation

Answer 10

representing the original program

usually done via three-address code (three is the maximum number of adresses)
using symbol table

Question 11

Code Optimizer

Answer 11

Goal: faster machine code
e.g. combinig things together, …