[Embedded] Linux development tools arm-linux-gcc installation and use

Linux development tools designed to make and makefile

Structure and level of knowledge - program compilation and debugging

Embedded cross compiler installation configuration

Host target board development model

• Host
  compile, link embedded computer software

• Target machine
  running embedded software, hardware platform

• "Local" compiler
  to generate object code that runs under the compiler itself where the same computer and operating system environment (platforms), Windows such as Windows environment to generate the object code.

• Cross compiler
  Used to generate the object code to run on other platforms, such as Windows Linux environment generates object code.

Under ARM microprocessor / Linux system compiler

The compiler naming rules
arch [-vendor] [-os] [-(gnu)eabi]-工具名称

• arch- architectures, such as ARM , MIPS
• vendor- tool chain providers, the CPU name or a development board manufacturers
• os- target operating systems, such as linux
• (gnu) eabi- the use of libraries, including glibc , EABI , uclibc three kinds

Example: arm-none-eabi-gcc

• Bare-metal system used to compile the ARM architecture

Example:arm-none-linux-gnueabi-gcc

• For Linux systems based on ARM architecture, based on GCC, Glibc library use
  after Codesourcery company introduced optimized compiler for compiling the ARM architecture u-boot, Linux kernel, linux applications.

Several important directories:
compiler tool directory:FriendlyARM/toolchain/4.9.3/bin

The compiler header file directory:FriendlyARM/toolchain/4.9.3/arm-cortexa9-linux-gnueabihf/sys-root/usr/include

Library file directory:FriendlyARM/toolchain/4.9.3/arm-cortexa9-linux-gnueabihf/sys-root/usr/lib

Download and install the compiler

You can go to the official website to download, http://www.linaro.org/downloads/
but more slowly, can be directly downloaded with me.
Links: https://pan.baidu.com/s/1jL_G6kbTC9h_bF8HHXBWxw extraction code: 67u4

1. First move the package to install the downloaded tmp directory under the root directory (/ tmp)

2. Use tar command to extract the installation package, the following command is entered in the Terminal :( preceding sudo indication root authority to execute the command)

sudo tar -xjvf /tmp/arm-linux-gcc-4.6.4-arm-x86_64.tar.bz2 -C /

Note that uppercase letters C, this command will opt to install the package and extract the root directory TuxamitoSoftToolchains inside (/ opt / TuxamitoSoftToolchains)

3. After the extraction is completed, and then create a new directory in the arm (/ usr / local), namely, enter the following command in the Terminal:

sudo mkdir /usr/local/arm

After you create a successful directory arm, also need to give it to liberate all the privileges that enter the following command in the Terminal:

sudo chmod 777 /usr/local/arm

4. Locate the extract from the directory and copy the entire gcc-4.6.4 directory to the newly-built arm directory, the command is as follows:
first cd to gcc 4.6.4-directory (after switching the first look there ls no gcc-4.6.4 directory):

cd /opt/TuxamitoSoftToolchains/arm-arm1176jzfssf-linux-gnueabi/

And then execute the copy command cp, -r represent anything inside as well as the entire directory

sudo cp -r gcc-4.6.4 /usr/local/arm

5. Open (/ etc / profile) configuration database environment variables and variables, the object is to be used later at any position of the cross compiler command is as follows:

sudo vi /etc/profile

After vi or vim open, adding two lines at the end of the file, and enter the following code: The first line is to add the program execution environment variables, the second line is the path of the library file

export PATH=$PATH:/usr/local/arm/gcc-4.6.4/bin
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/arm/gcc-4.6.4/lib

Then save out.

6. Use the source command to reload the configuration file to take effect

source /etc/profile

7. Verify that the installation was successful, output version information Enter the following command in Terminal:

arm-linux-gcc -v

arm-linux-gcc tool

arm-gcc-linux syntax: arm-linux-gcc [ option | filename ]...
Under normal circumstances, produce a new program needs to go through four stages: preprocessing, compiler, assembler, linker
, of course we can decide what steps to compile the operations performed by the end of the parameter
parameter range in Linux seek the help of the environment:man arm-linux -gcc

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-E

• Only the file preprocessing , but do not compile, assemble and link.

Example:
arm-linux -gcc -E hello.c -o hello1.c

Pretreatment, Hello.c contents:

After pretreatment, Hello1.c contents:

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-S

• Only the file compiled (generated assembler file .s) , but does not compile and link.

Example: arm-linux -gcc -S hello.c
the above example will generate a compiled file hello.s

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-c

• Only the file compiled and assembled, but it is not linked, meaning that only the program make obj file.

Example: arm-linux -gcc -c hello.c –o hello.o

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-o

• Specify the target name, the default time, gcc compiler is a.out file

Example:
arm-linux -gcc hello.cThe default compile hello.out
arm-linux -gcc -o hello.bin hello.ctarget noun is hello.bin
arm-linux -gcc -o hello.s -S hello.c

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-include file

• It contains a code that, in simple terms, is to compile a file when you need another file, you can use it to set function is equivalent to use in your code #include.

Example:arm-linux -gcc hello.c -include type.h

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-I dir

• If you use #include"file"time, gcc / g ++ will first look in the current directory you specified in the header files, if not found, the compiler will default to the header file directory to find;
• If you use a -Ispecified directory, the compiler will first look for the directory you specify, and then press the conventional sequential go.

Example: arm-linux -gcc -o hello -I/xxx/include hello.c

-I

• Before canceling function is a parameter, it is generally in -I dirafter use
  

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-iprefix prefix with -iwithprefix dir

These two parameters are generally used in conjunction, when -Ia directory lookup fails, to prefix+dirfind the next

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-l库名

• Specifies the compile time libraries used ( static library .a / DLL .so )

Example: arm-linux-gcc -lpthread hello.c
Specifies the use of phtread.cthe library

-L目录

• Compile time specified, the library search path. For example, your library, you can -Lspecify the directory where your library, otherwise the compiler will only find in the standard library directory . This diris the name of the directory.

Example:
arm-linux-gcc –L./ hello.c –o hello

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gcc optimization

Providing gcc in order to meet different levels of optimization of user needs and provide nearly a hundred kinds optimization options, used to { compile time , the target file size , the efficiency } This three-dimensional model of a different trade-offs and balancing. Optimization methods and so forth, as a whole will have the following categories:

1. Reduce operation instruction;
2. Try to meet the cpu pipelining;
3. By guess the behavior of the program, re-adjustment execution code sequence;
4. Full use of registers;
5. Calls for simple expansion, etc.

-O0, -O1, -O2, -O3
O0: do not do any optimization, which is the default compiler options
O3: highest level of optimization

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-g

• The compiler generates debugging information at compile time.

Example:
arm-linux –gcc –o hello -g hello.c

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after class homework

(1) belonging to the watchdog member ( hardware module ), which is a core function ( detection software code runaway ) and ( when the system is "running out" into the loop and restore the operation of the system ).

(2) assuming C code fun.c, which is compiled into object code fun.o, compile command arm-linux-gcc -c fun.c -o fun.o; if using a library function fun.c libcurses.a, and which together with the compiled executable main.c smartfun , the compiler command arm-linux-gcc -c fun.c main.c -lcurses -o smartfun.