Common configuration methods for using GDB to debug embedded ARM assembly-optimized programs under Linux

Common configuration methods for using GDB to debug embedded ARM assembly-optimized programs under Linux

In embedded system development, ARM architecture chips are a very common choice. In the writing process of ARM assembler, optimization is an integral part because it can significantly improve the performance of the program. However, since optimization is related to the simplification and reorganization of code, it also brings certain difficulties to debugging. This article will introduce how to use GDB to debug embedded ARM assembly optimized programs, and provide some common configuration methods and code examples.

1. Environment configuration

1. Install the ARM cross-compilation tool chain

First, we need to install the ARM cross-compilation tool chain in order to use it in the Linux environment Compile ARM assembler. Commonly used ARM cross-compilation tool chains include gcc, binutils, etc. It can be installed through the following command:

sudo apt-get install gcc-arm-linux-gnueabi

2. Write an ARM assembly optimized program

Next, write a simple ARM assembly optimized program as an example. The following is a sample code for an addition function:

.global add
.thumb_func
add:
    mov r2, r0
    add r0, r1, r0
    bx lr

The above code implements the addition operation of two numbers and returns to the caller using the bx lr instruction.

3. Compile and run the program

Use the cross-compilation tool chain to compile the assembly code into an executable file, for example:

arm-linux-gnueabi-gcc -o test test.s

Then, run the generated Executable file:

qemu-arm ./test

2. Use GDB to debug optimized ARM assembler

1. Configure to start GDB

You can start GDB through the following command, and Load the executable file:

arm-linux-gnueabi-gdb -q test

2. Set a breakpoint

In GDB, you can use the break command to set a breakpoint. For example, we can set a breakpoint at the entry of the function:

(gdb) break add

3. Start program debugging

Use the run command to start program debugging:

(gdb) run

The program will stop at the set breakpoint.

4. Single-step execution program

Use the stepi command to single-step the program, and you can execute ARM assembly instructions one by one. For example:

(gdb) stepi

5. View registers and memory

During the debugging process, we can use the info registers command to view the value of the register, use x command to view the contents of memory. For example:

(gdb) info registers
(gdb) x/4xw $sp

6. Debugging ends

After debugging, you can use the quit command to exit GDB.

3. Notes

1. Use static link library

When compiling an optimized ARM assembler, you should ensure that all required library files are statically linked to avoid file not found errors during debugging.

2. Optimization options

When compiling an optimized ARM assembler, you can use appropriate optimization options, such as -O2 to improve program performance. However, -O0 should be used when debugging to disable optimization to better trace the execution of the program.

3. Set the symbol table

In order to display the source code correctly in GDB, the symbol table should be generated through the -g option at compile time, for example:

arm-linux-gnueabi-gcc -g -o test test.s

In this way, the source code and function name can be displayed correctly in GDB.

Summary

Through this article, we learned how to use GDB to debug optimized embedded ARM assembler under Linux. When debugging optimized programs, we need to pay attention to configuration options and use debugging commands. These tips can help us better understand and debug optimized ARM assembly programs. I hope readers can learn some practical debugging skills through this article to better develop and debug ARM embedded systems.

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