Example of phase of compiler – Lexical/Syntax/Semantic Intermediate Code Target

Example of phase of compiler – Lexical/Syntax/Semantic Intermediate Code Target

Phases of a Compiler – Examples for Each Phase

A compiler translates high-level code into machine code through multiple phases. These phases can be categorized into front-end (analysis) and back-end (synthesis) processes.

 1. Lexical Analysis (Tokenization)

• Purpose: Converts source code into a sequence of tokens.

• Example:
  Input Code (C language):

  int x = 10;


  Output (Tokens):

  Keyword: int
Identifier: x
Operator: =
Number: 10
Symbol: ;


Tool Used: Lexical Analyzer (Lexer)

 2. Syntax Analysis (Parsing)

• Purpose: Checks if tokens form a valid syntax according to the language grammar.

• Example:
  Input Tokens:

  int x = 10;


  Parsing Tree (Abstract Syntax Tree – AST):

  =
/ \
int 10
\
x


  Error Detected: Missing semicolon (;) or incorrect placement of keywords.

Tool Used: Parser

 3. Semantic Analysis (Meaning Verification)

• Purpose: Ensures code makes logical sense (type checking, scope checking, etc.).

• Example:
  Input Code:

  int x;
x = "Hello"; // Error: Type mismatch


  Error: x is declared as an integer, but assigned a string value.

Tool Used: Semantic Analyzer

 4. Intermediate Code Generation

• Purpose: Converts the code into an intermediate representation (IR) that is independent of machine architecture.

• Example (Three-Address Code Representation):
  Input Code:

  a = b + c * d;


  Intermediate Code (Three-Address Code – TAC):

  t1 = c * d
t2 = b + t1
a = t2


Tool Used: Intermediate Code Generator

 5. Target Code Generation

• Purpose: Converts intermediate code into machine code (assembly language) for execution.

• Example (x86 Assembly Code):

  MOV R1, c
MUL R1, d
MOV R2, b
ADD R2, R1
MOV a, R2


Tool Used: Code Generator

 Summary Table

Would you like me to explain Compiler Optimizations as well?

Example of phase of compiler – Lexical/Syntax/Semantic Intermediate Code Target