GHC bindist with DWARF support seems much slower than non-DWARF
Comparing the DWARF and non-DWARF binary distributions, I'm seeing times for a cabal new-build --disable-profiling --disable-library-profiling all for a multi-library project showing e.g. 5:46.90 for DWARF, vs 3:56.40 for non-DWARF bindists.
I'm assuming this is unexpected since I don't see it proclaimed loudly anywhere.
I thought this was irrelevant, but I did try doing cabal new-build ... --enable-debug-info=0 with the DWARF-supporting GHC but that didn't seem to improve compile time. I don't see anything relevant in my ~/.cabal/config.
Even more confused because I see the same slow timing (~ 5:45) for a stack build in the same project, yet it looks like stack pulls in a GHC without DWARF-compiled libs:
$ readelf --debug-dump $HOME/.stack/programs/x86_64-linux/ghc-8.6.3/lib/ghc-8.6.3/text-1.2.3.1/libHStext-1.2.3.1-ghc8.6.3.so | grep Version
$ Maybe stack is compiling in a different way though, and the timing similarity is just a coincidence.
I first noticed this when building GHC from source. It seemed that uncommenting these caused the regression (though I haven't double-checked):
#GhcLibHcOpts += -g3
#GhcRtsHcOpts += -g3Attached is the project repo I tested with (again, with cabal new-clean && cabal new-build --disable-profiling --disable-library-profiling all).
Trac metadata
| Trac field | Value |
|---|---|
| Version | 8.6.3 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |