How can I get assembler output from my C/C code using GCC and objdump?

Getting Assembler Output from C/C Source in GCC

To analyze the compilation process, extracting the emitted assembly code is essential. One effective method is to employ the -S option in GCC (or G ).

Using the -S Option

By specifying -S, the preprocessor will process the source file, perform initial compilation, but halt before invoking the assembler. This allows you to examine the code before it goes through assembly. For improved readability, use -fverbose-asm.

gcc -S helloworld.c

The output file will be named helloworld.s by default. To change this, use the -o option.

gcc -S -o my_asm_output.s helloworld.c

Analyzing Existing Object Files

If you only have an object file, you can use objdump with the --disassemble (-d) option.

objdump -S --disassemble helloworld > helloworld.dump

For enhanced information, consider using -rwC (for symbol relocations and name demangling), -Mintel (for Intel syntax with x86), and -r (to include references from unlinked objects).

objdump -drwC -Mintel -S foo.o | less

These methods provide valuable insights into the compilation process, enabling you to analyze the assembly code of your C/C programs.

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