[llvm] r333147 - [ORC] Add findSymbolIn() wrapper to C bindings.

[Andres Freund via llvm-commits]

On 2018-05-23 20:24:16 -0700, Andres Freund wrote:
> Hi,
> 
> On 2018-05-24 01:01:42 -0000, Andres Freund via llvm-commits wrote:
> > Author: anarazel
> > Date: Wed May 23 18:01:42 2018
> > New Revision: 333147
> > 
> > URL: http://llvm.org/viewvc/llvm-project?rev=333147&view=rev
> > Log:
> > [ORC] Add findSymbolIn() wrapper to C bindings.
> > 
> > In many cases JIT users will know in which module a symbol
> > resides. Avoiding to search other modules can be more efficient. It
> > also allows to handle duplicate symbol names between modules.
> > 
> > Reviewed By: lhames
> > 
> > Differential Revision: https://reviews.llvm.org/D44889
> > 
> > Modified:
> >     llvm/trunk/include/llvm-c/OrcBindings.h
> >     llvm/trunk/lib/ExecutionEngine/Orc/OrcCBindings.cpp
> >     llvm/trunk/lib/ExecutionEngine/Orc/OrcCBindingsStack.h
> >     llvm/trunk/unittests/ExecutionEngine/Orc/OrcCAPITest.cpp
> 
> This unfortunately failed on the OSX builders:
> http://green.lab.llvm.org/green/job/clang-stage1-cmake-RA-incremental/48851/
> but not on others:
> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-global-isel/builds/5739
> http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-debian-fast/builds/8926/steps/test/logs/stdio
> ...
> 
> The green.lab.llvm.org builder seems to be OSX - I can't for the heck of
> me see what was OS specific in that change however.
> 
> I've organized remote access to an OSX laptop (using linux myself), and
> will build LLVM there to see whether I can reproduce the problem. On
> linux the tests pass, even under valgrind.

That helped. As far as I can tell the bug is in pre-existing code that
this commit exposed. Compare:

  JITSymbol findSymbol(const std::string &Name,
                                 bool ExportedSymbolsOnly) {
    if (auto Sym = IndirectStubsMgr->findStub(Name, ExportedSymbolsOnly))
      return Sym;
    return CODLayer.findSymbol(mangle(Name), ExportedSymbolsOnly);
  }

with

  JITSymbol findSymbolIn(orc::VModuleKey K, const std::string &Name,
                         bool ExportedSymbolsOnly) {
    assert(KeyLayers.count(K) && "looking up symbol in unknown module");
    return KeyLayers[K]->findSymbolIn(K, Name, ExportedSymbolsOnly);
  }

Note that the second function doesn't do a mangle(Name). On OSX the
actual symbol will have a '_' prefix, but without mangling the looked up
function won't.

I'll open a review about this.

Greetings,

Andres Freund