CODEWITHSUNDEEP
c++cmakeclangllvm
Shuzheng
Shuzheng

Reputation: 13840

CMakeList for ModuleMaker LLVM sample program

I'm trying to create a CMakeList for compiling the ModuleMaker sample program on Windows 10.

Everything seems fine, but I get the following error:

1>  C:\Program Files (x86)\LLVM\include\llvm/IR/Metadata.h(716): note: see reference to class template instantiation 'llvm::PointerUnion<llvm::LLVMContext *,llvm::ReplaceableMetadataImpl *>' being compiled
1>ModuleMaker.obj : error LNK2019: unresolved external symbol "void __cdecl llvm::WriteBitcodeToFile(class llvm::Module const *,class llvm::raw_ostream &,bool,class llvm::ModuleSummaryIndex const *,bool)" (?WriteBitcodeToFile@llvm@@YAXPBVModule@1@AAVraw_ostream@1@_NPBVModuleSummaryIndex@1@2@Z) referenced in function _main
1>C:\Users\nlykkei\llvm\src\examples\ModuleMaker\Debug\ModuleMaker.exe : fatal error LNK1120: 1 unresolved externals

I.e., all is linked fine, except the WriteBitcodeToFile function.

Do anyone have an idea why this is happening? If so, please provide an elaborate explanation.

Program:

#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/raw_ostream.h"

using namespace llvm;

int main() {
  LLVMContext Context;

  // Create the "module" or "program" or "translation unit" to hold the
  // function
  Module *M = new Module("test", Context);

  // Create the main function: first create the type 'int ()'
  FunctionType *FT =
    FunctionType::get(Type::getInt32Ty(Context), /*not vararg*/false);

  // By passing a module as the last parameter to the Function constructor,
  // it automatically gets appended to the Module.
  Function *F = Function::Create(FT, Function::ExternalLinkage, "main", M);

  // Add a basic block to the function... again, it automatically inserts
  // because of the last argument.
  BasicBlock *BB = BasicBlock::Create(Context, "EntryBlock", F);

  // Get pointers to the constant integers...
  Value *Two = ConstantInt::get(Type::getInt32Ty(Context), 2);
  Value *Three = ConstantInt::get(Type::getInt32Ty(Context), 3);

  // Create the add instruction... does not insert...
  Instruction *Add = BinaryOperator::Create(Instruction::Add, Two, Three,
                                            "addresult");

  // explicitly insert it into the basic block...
  BB->getInstList().push_back(Add);

  // Create the return instruction and add it to the basic block
  BB->getInstList().push_back(ReturnInst::Create(Context, Add));

  // Output the bitcode file to stdout
  WriteBitcodeToFile(M, outs());

  // Delete the module and all of its contents.
  delete M;
  return 0;
}

CMakeList.txt:

cmake_minimum_required(VERSION 3.4.3)
project(ModuleMaker)

find_package(LLVM REQUIRED CONFIG)

include_directories(${LLVM_INCLUDE_DIRS})
add_definitions(${LLVM_DEFINITIONS})

message(STATUS "Found LLVM ${LLVM_PACKAGE_VERSION}")
message(STATUS "Using LLVMConfig.cmake in: ${LLVM_DIR}")


add_executable(ModuleMaker ModuleMaker.cpp)

llvm_map_components_to_libnames(llvm_libs support core irreader)

target_link_libraries(ModuleMaker ${llvm_libs})

Upvotes: 0

Views: 207

Answers (1)

tambre
tambre

Reputation: 4853

You need to add bitwriter to llvm_map_components_to_libnames to also link with the bitwriter component and to use the WriteBitcodeToFile function.

The names of available LLVM components should be available through the LLVM_AVAILABLE_LIBS variable. For all available variables about LLVM see the LLVMConfig.cmake.in.

You could print the contents of the LLVM_AVAILABLE_LIBS by doing message(${LLVM_AVAILABLE_LIBS}).

Upvotes: 1

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