Compilation Stages for C Program

Compilation process:

Compilation is a process of converting human readable code into machine understandable code

Compilation process is divided into 4 stages/parts:

1. Pre-processor stage
2. Translator stage
3. Assembler stage
4. Linker stage

1. Pre-processor stage

• First stage of compilation process.
• In this stage we will get pure C file or extended c file from our source file.

       Pre-processor stage is responsible for:

• Including header files.
• Remove comments.
• Replace macros.
• Do conditional compilation.

2. Translator stage

• In this stage the code is converted into assembly language.

      Translator tasks are:

• To generate assembly code.
• Check for any syntactical error.

3. Assembler stage:

• In this stage the assembly language code is converted into machine understandable code or object code.
• The content of object file is in binary format, to make this file readable you will have to disassemble it.

4. Linker stage:

• Linker stage is the last stage of the compilation process.
• After completion of this stage the exe file is generated.

        Linker tasks are:

• Linking the libraries.
• Searching and linking function definitions (pre-defined or user defined).

For example: 

Consider, our file name is hello.c

• To compile till preprocessor stage

            cc -E hello.c -o hello.i

• To check output of preprocessor stage

            vi hello.i

• To compile till translator stage

            cc -S hello.i -o hello.s

• To check output of the translator stage

            vi hello.s

• To compile till assembler stage

            cc -c hello.s -o hello.o

• To check the assembler stage output

            vi hello.o

• The output file of assembler stage is in binary non readable to dissemble it

            objdump -D hello.o

• To compile till linker stage and generate .exe file at a time

            cc hello.c