Explain analysis and synthesis phase of a compiler.
The synthesis and analysis phases of a compiler are:
Analysis Phase: In this breaks the source program in constituent pieces and makes intermediate representation. This analysis part can be divided along the phases as follows:
1. Lexical Analysis- The program is seems as a unique sequence of characters. Its analyzer reads the program from left-to-right and then sequence of characters is grouped in tokens-lexical units along with a collective meaning.
2. Syntax Analysis- It is also termed as Parsing. Tokens are grouped in grammatical phrases represented through a Parse Tree that provides a hierarchical structure to the source program.
3. Semantic Analysis- The phase of semantic analysis checks the program for semantic errors (i.e. Type Checking) and then gathers type information for the successive phases.
Type Checking is check types of operands; not any real number as index for array and so on.
Synthesis Phase: Produces the target program from the intermediate representation. The part of synthesis can be divided along the phases as follows:
1. Intermediate Code Generator- An intermediate code is produced as a program for an abstract machine. The code of intermediate must be easy to translate in the target program.
2. Code Optimizer- Such phase attempts to enhance the intermediate code therefore faster-running machine code can be acquired. Various compilers adopt various optimization techniques.
3. Code Generator- In this phase generates the target code containing assembly code. Now
1. Memory locations are chosen for each variable;
2. Instructions are translated in a sequence of assembly instructions;
3. Intermediate and variables results are allocated to memory registers.