How Can I Generate Assembly Code from C/C Source Using GCC?

Generating Assembler Output from C/C Source in GCC

To analyze the compilation process, obtaining the emitted assembly code from C/C source can be invaluable. GCC offers two methods to achieve this: using the -S option and utilizing objdump.

Using the -S Option:

The -S option instructs GCC to run the preprocessor and perform initial compilation, but halt before assembler execution. By default, the output is stored in a file with the .s extension. To specify a custom output file, use the -o option.

Using objdump:

If you only have the resulting object file, you can use objdump with the --disassemble option (-d for a shorter version) to disassemble the code:

Additional Options:

• -fverbose-asm (for gcc) offers detailed comments about C operands in the assembly code.
• -rwC (objdump) displays symbol relocations, disables line wrapping, and unmangles C names.
• -Mintel (objdump) changes the disassembly syntax to Intel for x86 architectures.

Example:

To obtain detailed assembler output with Intel syntax from a .o file that may contain placeholders for symbol references, use:

The above is the detailed content of How Can I Generate Assembly Code from C/C Source Using GCC?. For more information, please follow other related articles on the PHP Chinese website!