[PATCH] D99238: [DebugInfo] Enable the call site parameter feature by default

Fri Apr 2 10:44:31 PDT 2021

dblaikie 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()))
----------------
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.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99238/new/

https://reviews.llvm.org/D99238