Shulou(Shulou.com)06/02 Report--

Brief introduction

Please talk about how the linux source file is gradually compiled into an executable file.

Solution

First of all, the above figure has a perceptual understanding of the whole process of compilation, and then analyze each process step by step.

Take hello.c program as an example

# include main {printf ("hello\ n");}

A .c source program needs to generate a .i file through a preprocessor, a .s file through the compiler, a relocatable object file .o file through the assembler, and a linker with other .o files to generate the final executable object program.

Pretreatment stage. It mainly deals with the precompiled instructions in the source file that begin with "#".

Delete # define and expand the macro

Handle all conditional precompiled instructions, such as # if, # ifdef, # endif

Insert header file into "# include"

Delete all comments

Add line number and file name identification so that the compiler generates line number information for debugging at compile time

Retain all # pragma compilation instructions.

The compilation phase. The preprocessed files are analyzed by syntax analysis, lexical analysis, semantic analysis and optimization, and the assembly code file (assembly language source program) is generated.

The assembly stage. Assembler (assembler) is used to convert assembly language source programs into machine instruction sequences (machine language programs).

Link phase. Merge multiple relocatable object files .o to produce an executable file, which can be loaded into memory and executed by the system.

Summary

The above is all about the parsing of the process of compiling the source file into the target file under Linux. I hope it will be helpful to you. Interested friends can continue to refer to other related topics on this site, if there are any deficiencies, please leave a message to point out. Thank you for your support to this site!

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