stg_upd_frame_info still broken

Reid Barton rwbarton at
Tue Oct 27 14:56:44 UTC 2015

On Tue, Oct 27, 2015 at 10:46 AM, Ben Gamari <ben at> wrote:

> Simon Peyton Jones <simonpj at> writes:
> > I cloned an entirely new GHC repository.
> > Then 'sh validate'.
> > Same result as before: any attempt to run GHCi fails with an unresolved
> symbol.
> >
> > bash$ c:/code/HEAD-1/inplace/bin/ghc-stage2 --interactive
> >
> > GHCi, version 7.11.20151026:  :? for help
> >
> > ghc-stage2.exe: unable to load package `ghc-prim-'
> >
> > ghc-stage2.exe:
> C:\code\HEAD-1\libraries\ghc-prim\dist-install\build\HSghc-prim-
> unknown symbol `_stg_upd_frame_info'
> >
> > How could I actually find what the problem is? Trying random things
> > and hoping the problem goes away clearly is not working.
> >
> I would first try to find the object file which is supposed to provide
> this symbol and figure out whether the problem is one of the RTL
> (which is what I would put my money on) or some part of the build
> toolchain.

 I'm pretty sure this error is being produced by ghc's own runtime linker,
which has a built-in symbol table (essentially just a C array of structs of
{ "foo", &foo }). This array is built from a bunch of macros such as
SymI_HasProto(stg_upd_frame_info), which used to be present in rts/Linker.c
but were moved to rts/RtsSymbols.c in commit abc214b77d. I guess that
commit or a related one was not correct. Windows is the only (major?)
platform on which the ghc executable is built statically by default, and
therefore uses ghc's own runtime linker.

I'll try building a Linux ghc with GHC_DYNAMIC=NO and if it exhibits the
same problem I should be able to provide a quick fix.

Reid Barton
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