cpp
The preprocessor which processes all the header files and macros that your target requires.

gcc

The compiler which produces assembly language code from the processed C files. For more information, see Using GNU CC in GNUPro Compiler Tools.

as

The assembler which produces binary code from the assembly language code and puts it in an object file.

ld

The linker which binds the code to addresses, links the startup file and libraries to the object file, and produces the executable binary image.
 

You have four implicit file extensions: .c, .C, .s, and .S. For more information, see Using GNU CC in GNUPro Compiler Tools.