Front End and Back End is an important technique during complier constructions. Compiler is divided into two groups Front End and Back End. Front End deals with the source language of the compiler. Back End deals with the target language of compiler. If source language changes than we only need to change the Front End of the compiler. If target language is changes, then we only change the Back End of compiler.
In bootstrapping process we write "Quick and Dirty" complier in assembly language for C language. Then write an efficient compiler in C language (lets say B) and give it as input to "Quick and Dirty" compiler. Compile compiler B through the latest compiler to get efficient compiler. Let explain this process through an example. We have a compiler of C Language that runs on Intel. Now we want a compiler of C language that runs on AMD. In this we write front end module and compile our program in Intel bas machine. We get a cross compiler that runs on Intel machine but generates code for AMD machine. We compile the source program on cross compiler and get a compiler that runs on AMD machine and generates code for MAD machine.
In bootstrapping process we write "Quick and Dirty" complier in assembly language for C language. Then write an efficient compiler in C language (lets say B) and give it as input to "Quick and Dirty" compiler. Compile compiler B through the latest compiler to get efficient compiler. Let explain this process through an example. We have a compiler of C Language that runs on Intel. Now we want a compiler of C language that runs on AMD. In this we write front end module and compile our program in Intel bas machine. We get a cross compiler that runs on Intel machine but generates code for AMD machine. We compile the source program on cross compiler and get a compiler that runs on AMD machine and generates code for MAD machine.