[llvm-dev] llvm interpreter does not find function defined by addGlobalMapping

[Lang Hames via llvm-dev]

Hi Markus,

What happens if you set the data layout on pModule before creating the
engine?

- Lang.

On Mon, Sep 19, 2016 at 5:34 AM, via llvm-dev <llvm-dev at lists.llvm.org>
wrote:

> Hi,
>
> I want to use a function defined in c(++)-code from code generated by
> llvm. For this I use ExecutionEngine.addGlobalMapping(). I started with
> the JIT execution engine and everything worked, then I switched to the
> interpreter engine and it stopped working, but only if compiled on a Linux
> system. More precisely it works if I use
>
>     llvm 3.8.1 + gcc (Linux) + JIT
>     llvm 3.8.0 + mingw-gcc (Windows) + JIT
>     llvm 3.8.0 + mingw-gcc (Windows) + Interpreter
>
> But it does not work for llvm 3.8.1 + gcc (Linux) + Interpreter. In that
> case I get the error message "LLVM ERROR: Tried to execute an unknown
> external function: testFunction." Am I using ExecutionEngine.addGlobalMapping()
> in the wrong way, even it works in three out of four scenarios?
>
> #include <llvm/Support/TargetSelect.h>
> #include <llvm/Analysis/Passes.h>
> #include <llvm/Transforms/Scalar.h>
> #include <llvm/Transforms/IPO/PassManagerBuilder.h>
> #include <llvm/Transforms/IPO.h>
> #include <llvm/IR/Verifier.h>
> #include <llvm/ExecutionEngine/ExecutionEngine.h>
> #include <llvm/ExecutionEngine/Interpreter.h>
> #include <llvm/ExecutionEngine/MCJIT.h>
> #include <llvm/ExecutionEngine/GenericValue.h>
> #include <llvm/IR/LegacyPassManager.h>
> #include <llvm/IR/IRBuilder.h>
>
> extern "C" double testFunction(){
>   return 42.0;
> }
>
> int main() {
>   // initialization needed for JIT
>   llvm::InitializeNativeTarget();
>   llvm::InitializeNativeTargetAsmPrinter();
>   llvm::InitializeNativeTargetAsmParser();
>
>   llvm::LLVMContext &context(llvm::getGlobalContext());
>   llvm::Module *pModule = new llvm::Module("a module", context);
>
>   // Here the EngineKind-flag decides if JIT or interpreter is used.
>   auto pExecutionEngine = llvm::EngineBuilder(std::
> unique_ptr<llvm::Module>(pModule)
>     ).setEngineKind(llvm::EngineKind::Interpreter).create();
>   pModule->setDataLayout(pExecutionEngine->getDataLayout());
>
>   // declaration of the c function.
>   std::vector<llvm::Type *> noArgTypes;
>   llvm::FunctionType* ft = llvm::FunctionType::get(llvm::
> Type::getDoubleTy(context),noArgTypes, false);
>   auto pFunction = llvm::Function::Create(ft, llvm::Function::ExternalLinkage,
> "testFunction",pModule);
>   pExecutionEngine->addGlobalMapping(pFunction,reinterpret_cast<void*>(&
> testFunction));
>
>   // generation of llvm code
>   auto pBlock = llvm::BasicBlock::Create(context, "evaluation");
>   llvm::IRBuilder<> builder(context);
>   builder.SetInsertPoint(pBlock);
>
>   // code for call of the c function.
>   auto pFunction2 = pModule->getFunction("testFunction");
>   auto temp = builder.CreateCall(pFunction2, std::vector<llvm::Value*>(),
> "calltmp");
>   builder.CreateRet(temp);
>
>   // generation of the llvm function calling the c function
>   llvm::FunctionType* ftWrapper = llvm::FunctionType::get(llvm::
> Type::getDoubleTy(context),noArgTypes, false);
>   auto pWrapperFunction = llvm::Function::Create(ftWrapper,
> llvm::Function::ExternalLinkage, "AFunction",pModule);
>   pWrapperFunction->getBasicBlockList().push_back(pBlock);
>
>   // calling the generated llvm function
>   pExecutionEngine->finalizeObject();
>   pExecutionEngine->runFunction(pWrapperFunction,std::vector<
> llvm::GenericValue>());
> }
>
> Thanks for any help,
> Markus
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20161020/49a901ae/attachment.html>