Compiler Construction
Compiler-a program that translates an executable program in one language into an executable program in another language
Interpreter-a program that reads an executable program and produces the results of running that program
Why do we care to study compiler construction
Compiler construction is a microcosm of computer science artificial intelligence greedy algorithms learning algorithms
Algorithms
graph algorithms union-find dynamic programming
Theory
DFAs for scanning parser generators lattice theory for analysis
Systems
allocation and naming locality synchronization
Architecture
pipeline management hierarchy management instruction set use
Is Compiler construction not a solved problem?
Machines are constantly changing
Changes in architecture changes in compilers new features pose new problems changing costs lead to different concerns old solutions need re-engineering
Innovations in compilers should prompt changes in architecture
New languages and features
What qualities are important in a good compiler?
1. Correct code
2. Output runs fast
3. Compiler runs fast
4. Compile time proportional to program size
5. Support for separate compilation
6. Good diagnostics for syntax errors
7. Works well with the debugger
8. Good diagnostics for flow anomalies
9. Cross language calls
10. Consistent, predictable optimization
What role does a Scanner plays in a compiler? map characters to tokens character string value for a token is a lexeme eliminate white space character string value for a token is a lexeme, Typical tokens: id, number, do, end …, Key issue is speed
Why the need for Parser? recognize context-free syntax guide context-sensitive analysis construct IR(s) produce meaningful error messages attempt error correction
Define a Context-free grammar-
Context-free syntax is specified with a grammar, usually in Backus-Naur form (BNF)
How are context-free grammars specified?
A grammar G = (S,N,T,P)
S is the start-symbol
N is a set of
Interpreter-a program that reads an executable program and produces the results of running that program
Why do we care to study compiler construction
Compiler construction is a microcosm of computer science artificial intelligence greedy algorithms learning algorithms
Algorithms
graph algorithms union-find dynamic programming
Theory
DFAs for scanning parser generators lattice theory for analysis
Systems
allocation and naming locality synchronization
Architecture
pipeline management hierarchy management instruction set use
Is Compiler construction not a solved problem?
Machines are constantly changing
Changes in architecture changes in compilers new features pose new problems changing costs lead to different concerns old solutions need re-engineering
Innovations in compilers should prompt changes in architecture
New languages and features
What qualities are important in a good compiler?
1. Correct code
2. Output runs fast
3. Compiler runs fast
4. Compile time proportional to program size
5. Support for separate compilation
6. Good diagnostics for syntax errors
7. Works well with the debugger
8. Good diagnostics for flow anomalies
9. Cross language calls
10. Consistent, predictable optimization
What role does a Scanner plays in a compiler? map characters to tokens character string value for a token is a lexeme eliminate white space character string value for a token is a lexeme, Typical tokens: id, number, do, end …, Key issue is speed
Why the need for Parser? recognize context-free syntax guide context-sensitive analysis construct IR(s) produce meaningful error messages attempt error correction
Define a Context-free grammar-
Context-free syntax is specified with a grammar, usually in Backus-Naur form (BNF)
How are context-free grammars specified?
A grammar G = (S,N,T,P)
S is the start-symbol
N is a set of