Explain analysis and synthesis phase of a compiler.

Ans:
The analysis and synthesis phases of a compiler are:
Analysis Phase: Breaks the source program into constituent pieces and creates intermediate representation. The analysis part can be divided along the following phases:
1. Lexical Analysis- The program is considered as a unique sequence of characters. The Lexical Analyzer reads the program from left-to-right and sequence of characters is grouped into tokens–lexical units with a collective meaning.
2. Syntax Analysis- The Syntactic Analysis is also called Parsing. Tokens are grouped into grammatical phrases represented by a Parse Tree, which gives a hierarchical structure to the source program.
3. Semantic Analysis- The Semantic Analysis phase checks the program for semantic errors (Type Checking) and gathers type information for the successive phases. Type Checking check types of operands; No real number as index for array; etc.
Synthesis Phase: Generates the target program from the intermediate representation. The synthesis part can be divided along the following phases:
1. Intermediate Code Generator- An intermediate code is generated as a program for an abstract machine. The intermediate code should be easy to translate into the target program.
2. Code Optimizer- This phase attempts to improve the intermediate code so that faster-running machine code can be obtained. Different compilers adopt different optimization techniques.
3. Code Generator- This phase generates the target code consisting of assembly code. Here
1. Memory locations are selected for each variable;
2. Instructions are translated into a sequence of assembly instructions;
3. Variables and intermediate results are assigned to memory registers.