[PATCH] D42581: [NVPTX] Emit debug info in DWARF-2 by default for Cuda devices.

[Alexey Bataev via Phabricator via cfe-commits]

ABataev added inline comments.


================
Comment at: lib/Driver/ToolChains/Cuda.cpp:353
   CmdArgs.push_back(Args.MakeArgString(Output.getFilename()));
+  if (mustEmitDebugInfo(Args) && Args.hasArg(options::OPT_g_Flag))
+    CmdArgs.push_back("-g");
----------------
tra wrote:
> ABataev wrote:
> > tra wrote:
> > > ABataev wrote:
> > > > tra wrote:
> > > > > There's more than one -g option. Presumably you still want -g here for -g{1,2,3} or -ggdb{1,2,3} or -gdwarf2.
> > > > > 
> > > > > Speaking of dwarf, what's going to happen if someone passes -gdwarf5?  Should we downgrade it to -gdwarf2 on device side and issue a warning?
> > > > > 
> > > > That's exactly what I want to avoid. I think we can ignore these options and handle only `-g` option.
> > > > Or I can add a function to ToolChain class to force using the default settings for debugger tuning and DWARF version rather than take them from the driver options.
> > > You should handle at least -gN/-gline-tables-only/-g. Now that we can emit dwarf debug info, I would want to be able to control it to some degree -- off/line-info-only/full.
> > > 
> > > I'm still not sure what's the plan for -gdwarfN unsupported on device side? 
> > > - do we ignore it and always emit dwarf2?
> > > - do we accept it, emit requested version and let user stare at ptxas (or cuda-gdb) errors when it fails to deal with it?
> > > 
> > > 
> > > 
> > > 
> > 1. Ok, will look at this
> > 2. -gdwarfN should be ignored, we should always emit DWARF2, otherwise, it will break ptxas.
> Works for me. Please add a test to verify that it's always dwarf2 on device side.
After some thoughts, I think it would better to follow Paul's suggestion, i.e. force DWARF2 for NVPTX in the backend. In this case, -gdwarfN will not break anything in the debug info for NVPTX.


Repository:
  rC Clang

https://reviews.llvm.org/D42581