alok marked an inline comment as done.
alok added inline comments.
================
Comment at: clang/lib/Frontend/CompilerInvocation.cpp:1648
- if (Opts.OptimizationLevel > 0 && Opts.hasReducedDebugInfo() &&
+ if (Opts.hasReducedDebugInfo() &&
llvm::is_contained(DebugEntryValueArchs, T.getArch()))
----------------
dblaikie wrote:
> alok wrote:
> > alok wrote:
> > > dblaikie wrote:
> > > > probinson wrote:
> > > > > I think we don't want this enabled by default at -O0. It doesn't run
> > > > > any optimizations that should eliminate parameters, so this is going
> > > > > to increase debug info size for no real benefit to the debugging
> > > > > experience.
> > > > +1 to @probinson here. That's generally been the thinking behind why
> > > > this was only enabled when optimizations are enabled. (there's some
> > > > minor tradeoff here: call site descriptions in unoptimized code can
> > > > still be useful if they call into optimized code, so this is a bit
> > > > heuristical - assuming that all code will be compiled with the same
> > > > optimization level)
> > > >
> > > > If flang is in a different situation and enables some optimizations at
> > > > -O0 that make call site parameter descriptions beneficial even there,
> > > > then maybe we'll need some different way to differentiate optimizations
> > > > V no optimizations for the purpose of this feature.
> > > Thanks Paul for the comment. I shall probably add an option to enable in
> > > such cases which should remain off by default, Flang driver can pass that
> > > to compiler to turn it on.
> > Thanks David for your explanation and thoughts. Please also look at trigger
> > to this https://reviews.llvm.org/D99160
> >
> > It is needed in a Fortran case. I shall probably drop to enable it by
> > default and add an option which by default is disabled and Fortran driver
> > can pass that to make use of it.
> Sounds like @djtodoro is suggesting in
> https://reviews.llvm.org/D99160#2666106 that the "Bug" to fix here is the
> presence of DW_OP_call_value at -O0, it seems that could be an issue for the
> existing/original use of call_site_parameter/call_value (in C++/clang) as it
> would be for flang - so the fix should probably not be flang-specific if the
> issue isn't flang-specific. Understanding why we produce DW_OP_call_values at
> -O0, whether we can/should avoid that, what it costs (how much larger the
> debug info gets by adding DW_TAG_call_sites at -O0) would be necessary to
> determine the right path forward here.
Thanks David for clarification. I shall look at it and get back.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D99238/new/
https://reviews.llvm.org/D99238
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