CODEWITHSUNDEEP
debugginglldbsource-mapsdebug-symbols
John O
John O

Reputation: 5423

How do I inform lldb debugger where the source code is?

I have an executable that makes use of /usr/lib/libcrypto.0.9.8.dylib. I've (more or less) figured out some breakpoints within that library that I'd like to understand better.

However, I do not remember if this is the stock openssl on the system, or if I later installed it (don't think so, pretty sure that homebrew would have put it elsewhere).

This is for macOS Mojave (10.14). If the debug symbols have been stripped in libcrypto, I'm not sure I even know how to check that (nm?). I have, however, downloaded and extracted the source (matching the version).

Is there any way to configure lldb such that it can show me the source code instead of assembly language? If the debugging symbols have been stripped (without even checking, I'd assume so) can you even do this?

I'm trying to do my own research for this, but I'm not even sure I know what keywords to search with yet.

Upvotes: 0

Views: 901

Answers (1)

Jim Ingham
Jim Ingham

Reputation: 27110

The tools on Darwin don't store debug information in the binaries, but rather in a separate standalone bundle (a dSYM). So if you don't have a dSYM for your libcrypto then you don't have debug information for it, and there's no way to reconstruct the code->source map.

Some distributions have debug packages as well as release ones that include the dSYM's. lldb matches dSYM to binary using a common UUID computed by the linker. You can print the UUID with the command dwarfdump --uuid <PATH TO BINARY> and then see if wherever you got the library from kept that dSYM.

But if you can't find the dSYM, you aren't going to be able to do any source level debugging.

Upvotes: 0

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