Producing DWARF on PE/COFF targets

Brainstorming
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1

I’m playing with UEFI and right now the compiler outputs .pdb file for debug symbols which is 0.001% as useful as a punched card deck unless you use Microsoft tooling. LLVM has a way to produce separate DWARF for PE files, but looks like there is no way to trigger it without patching the compiler itself? In general, the build system should have a way to inject LLVM parameters for stuff it’s doesn’t know about, rather than assume “if I don’t need that, then nobody does”.

2

See this merged pull request: Dwarf on windows

  • Emit Dwarf debug info if targetting gnu abi on windows (maybe this should be a flag instead)
  • Add support for reading Dwarf info from COFF executables for stack and error tracing
3

Thanks dimdin. But maybe I’m being dumb, but while the pull request says “Emit Dwarf debug info if targetting gnu abi on windows” I can’t see any emit code/LLVM parameter passing, only parsing? And in 0.13.0 debug_info isn’t even used anywere…

4

I am not sure that this is going to work but I find some kind of support.
Try to search for dwarf debug section in the image even if a pdb file is generated.

For C the flag is: -gdwarf
For Zig the flags are: -gdwarf32 and -gdwarf64
In std.Build.Module there is the dwarf_format member that controls the -gdwarf32 and -gdwarf64 flags.