C Compilation Steps

C Compilation Steps

The above diagram shows the C Compilation steps.

STEP 1: Preprocessor

The main function of the C preprocessor is to remove comments from the source code and

interpret preprocessor directives which are given by the statements that begin with #. the preprocessor would strip the source of the comments contained

within the /*...*/ and would include the files assossiated with #include statement

and finally generates hello.i file

STEP 2:Compiler

Once the C preprocessor has stripped the source code of the comments and expanded the

preprocessor directives given by the lines that begin with # , the compiler translates the C

code into assembly language, which is a machine level code that contains instructions that

manipulate the memory and processor directly, in a layer beneath the operating system.

compiler is directly responsible for converting C syntax into this machine level code.

 And finally generates  hello.s 

STEP 3:Assembler
converts the machine-level instructions into binary code.
Assembler generates the objective file hello.o
The object file hello.o contains a binary version of the machine language

STEP 4:Linker/Link Editor
If a source file references library functions or functions defined in other source files the link editor combines these functions (with main()) to create an executable file. External Variable references resolved here also. 
means it will includes all the libraries,other Object files/Modules.

STEP 5: Loader
Makes use of binary format interpreter and process executable file header,it also determines the sizeof exe image.

coordinates with virtual memory subsystem and allocates Virtual memory address space required to load the program image.

Copies the exe image to virtual memory space allocated.

invokes process management sub system to process the registration of the exe.

Process management subsystem allocates a process control block(PCB) object and register a process

PCBs are linked up for CPU time from Scheduler.

A process once acquire CPU slice will start execution.