Making objdump -S find your source code

We all know the situation: We want to disassemble the most awesome pre-compiled object file, with accompanying sources, using objdump and we would like to view the assembly and C-code interleaved, so we use -S. Unfortunately, objdump fails to find the sources, and we are sad 🙁

How does objdump look for the sources? Normally the paths are hardcoded in the object file in the DWARF information. To inspect the DWARF debug info:

$ objdump --dwarf myobject.o | less

and look for DW_TAG_compile_unit sections, where the paths should exist like:

<25> DW_AT_name : C:/ARM/myfile.c


Of course, this might not be the path you have on your machine, and thus objdump gives up.

However, we can use an undocumented option to objdump: the -I or –include:

$ objdump -I ../mysources -S myobject.o | less

and voila, objdump finds the sources, inlines the C-code, and everything is awesome!