[cfe-dev] GCOV and stripping debug info

[Adrian Prantl via cfe-dev]

> On Jan 10, 2018, at 11:40 AM, David Blaikie <dblaikie at gmail.com> wrote:
> 
> Implementing GCOV in the new pass manager  (r322126) I'm wondering whether the addition of a "StripSymbols(OnlyDebugInfo = true)" pass is needed - and maybe that functionality in general can be removed?
> 
> It was added, I believe, before we had the "NoDebug" style debug info, used specifically for profiling, optimization remarks, etc. So when this was implemented, stripping the debug info was probably necessary to avoid actually emitting debug info into the resulting object files.
> 
> This could be useful in an LTO like build, if you know the debug info is not needed at the LTO stage - strip it out at the end of the frontend compile to reduce the size of bitcode files.

You mean that for LTO scheduling an explicit StripSymbols pass is an advantage over just using the NoDebug, which only causes the baclkend to ignore it? But the debug info will probably be needed for optimization remarks during LTO time, wouldn't it?

> 
> So... does this seem relevant here? In general? (I haven't looked at what other uses)

As one datapoint, I didn't know we had StripSymbols(OnlyDebugInfo = true) as a pass (I only knew about the llvm::stripDebugInfo() functions). Grepping for other uses of StripSymbols and stripDebugInfo might be a good start.

-- adrian
> 
> Totally happy to port the StripSymbols pass to the new pass manager if it seems like it's useful/necessary.
> 
> - Dave