In the world of programming and computer science, compiler helps to rewrite source code into human understandable code. It helps machine understand the human written code and it helps humans understand the machine code. But what is actually that a compilers do to achieve this task? In this article, we will take see all the phases of compiler that it goes through for the conversion of human language to machine and machine code to high level language.

What is a Compiler?

Before moving on to the phases of compiler, let's have a small comprehension of what is compiler first. A compiler is essentially a software program that converts human-readable source code written in a high level programming like Java or C++ into the machine code, that is understandable by a computer hardware. Primarily, this acts as a link between what human can read from the code and what machine can process in the form of instruction, thus, ensuring that the program will be a life support of the developer intention.

Importance of Compilers

Compilers are indispensable tools in software development for several reasons: 

1. Translation: They translate the human content using the source code into a machine readable instruction, accordingly computers will follow the instructions.

2. Optimization: Compilation is a process when the code is optimized resulting in better performance that enables computers to have faster programs that also use lesser resources.

3. Error Detection: Grammar and syntax checking of the source code does that - the errors in the code are discovered by the developers that way, and the result is no bugs.

4. Portability: Compilers make it possible for programs to run on different hardware architectures by carrying on the translation of code into instructions that are relevant to the specific architecture of a given machine.

Types of Compilers

Before diving into the phases, it's essential to understand the different types of compilers: 

1. Cross Compiler: It acts as a back-end tool that combines all the versions of the code and ensures that portability and platform independency are warranted.

2. Just-in-Time (JIT) Compiler: Compiles code at real-time and perform speed optimization by killing the compute if it is redundant.

3. Source-to-Source Compiler: Compiles the code from one high-level language to another sequences that renders two languages compatible.

4. Bytecode Compiler: Generates intermediary bytecodes which can further be interpreted when required or fully compiled for execution.
 

5. Binary Compiler: Translates the source code in an application language into a binary file in machine language and is used for programming low level tasks.

6. Hardware Compiler: Prepares a code uniquely written for hardware platforms, for instance, embedded systems or user-oriented operating systems.

Phases of Compilers

Now, let's explore the six essential phases of compilers: 

1. Lexical Analysis: Additionally, termed as scanning, this phase probes into and reads source code from top to bottom character by character; and divides it down to tokens. They are the basic units of the programming language, like the terms, names of the literals and operators.

2. Syntax Analysis: Subsequently, the compiler conducts a syntax check of the source code by breaking it into separate sections that are then compared to the syntactic rules of the assigned language. It modifies AST or parse tree to represent the syntax of code structure.

3. Semantic Analysis: The compiler verifies the syntax and then goes on to the semantics analysis in order to confirm if the code is coherent both with its meaning and the context in which it is written. It verifies the type consistency, nondisclosure of variables and other semantic wrongness, to make the program imperatively accurate.

4. Intermediate Code Generation: This phase represents a constructive stage which the source code is dissimulated to the form which is easily introspected and optimized. This way, code is converted from a simple form into an intelligible medium that can be easily recognized.

5. Optimization: The last optional step is when the compiler together with a bunch of optimization methods, use the intermediate code to generate the machine code, which will be used by the processor to execute the applications, and aim at improving the performance of the generated machine code. Optimization is targeted at trimming down running time, memory occupancy, and other resources. While doing this, the program functionality is to be preserved or even improved.

6. Code Generation: Through the last phases of the compiler optimized intermediate code is translated into machine code that is suitable to execute on the target hardware. During this phase, an intermediate code that is abstracted by the serial operations is translated into target architecture specific instruction pattern.

Conclusion

Finally, an overview of the entire source code translation process, which is accomplished through a set of complex phases of the compilers, is given. From interactive checking of the lexical entries to code generation each phase is pivotal for program correctness, performance and code portability. Developers get to view within the phases compilers which helps to realize complex processes of these tools which in turn they may evolve to write more competent and stable software.