5th lesson Embedded C language Compiler

1. GCC and gcc

(1)GCC: (GNU Compiler Collection)

GNU　　 Compiler collection that contains compilers for many languages, such as C, C + +, Java, D, Objective-c, and so on

(2)gcc: specifically the C language compiler in GCC

(3) GCC and embedded: Most embedded operating systems are based on GCC for source code compilation. such as Linux, VxWorks, Android and so on.

(4) in the actual development, the kernel development generally uses GCC, the application development general uses the GCC/G++/GDC

2. Cross- compiling

(1) Background

① embedded devices tend to be resource constrained

② can not directly program the processor on the embedded

(2) Solutions

① compiling the source code on the development host (PC)

② an executable program that eventually generates a target host (embedded device)

(3) How does gcc cross-compile?

① Configuring the target host's compilation Toolchain (for example: Arm-linux)

② the specific version of the Configuration tool chain (select the appropriate toolchain version according to the specific target code and use the special compilation options about the hardware architecture correctly)

(4) Case: Enterprise Embedded development environment

3. Initial knowledge of compilers

(1) Compiler composition

(2) Compilation process

(3) Extension problem: Multi-language mixed development

① Development Mode 1: from language to language (e.g.. Netframe frame)

② Development Method 2: From language to executable binary code (such as development of QQ)

③ Development Mode 3:

4. GCC key compilation Options

(1) Preprocessing directive: gcc- e file.c-o file.i

(2) compiler directive: gcc- s file.i-o file.s

(3) Assembly instructions: gcc- c file.s–o FILE.O

(4) Generate mapping file: gcc -wl,-mp=test.map file.c

(5) macro definition: gcc- d ' test= "TEST" ' file.c

(6) Get System header file path: gcc- v file.c

(7) Generate dependencies:

① get the full dependency of the target: gcc- m test.c

② get a partial dependency on a target: gcc -mm test.c

(8) Specify the library file and library file search path:

①GCC test.c- l. - Lfunc//. Indicates the current directory

② Where-l option specifies the search path for the library file, the-l option specifies the library file

"Instance Analysis" GCC compilation options

5th lesson Embedded C language Compiler