[gcc][clang] Put debug info into separate file

-gsplit-dwarf

Separate as much DWARF debugging information as possible into a separate output file with the extension .dwo. This option allows the build system to avoid linking files with debug information. To be useful, this option requires a debugger capable of reading .dwo files.-gpubnames

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clang -gsplit-dwarf -g foo.c -o foo.o 

clang -gsplit-dwarf -g bar.c -o bar.o
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Quote:

For a dwarf file for the entire program we need to use the 

dwp utility

to merge all of the various .dwo files into a single package file. 

Need to use the clang driver to do the first part since it knows how to invoke objcopy on each individual file, llc doesn't have the knowledge built into it (though it'll produce correct dwarf output, it just won't split it out).

Reference:

https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html

https://stackoverflow.com/questions/31495312/how-to-dump-dwarf-information-into-a-file-while-llvm-compiles