llvm-tutorial/source/JIT.cpp

//LLVM includes
#include "llvm/Analysis/Passes.h"

// Local includes
#include "JIT.h"

using namespace ast;
using namespace llvm;
using namespace llvm::orc;

namespace jit{

std::unique_ptr<llvm::legacy::FunctionPassManager> JITObjects::TheFPM =
    std::make_unique<llvm::legacy::FunctionPassManager>(AstObjects::TheModule.get());
std::unique_ptr<llvm::orc::KaleidoscopeJIT> JITObjects::TheJIT =
    std::unique_ptr<llvm::orc::KaleidoscopeJIT>(nullptr);
std::map<std::string, std::unique_ptr<ast::PrototypeAST>> JITObjects::FunctionProtos{};

void InitializeModuleAndPassManager(void) {
  // Open a new module.
  AstObjects::TheModule = llvm::make_unique<Module>("my cool jit", getGlobalContext());
  AstObjects::TheModule->setDataLayout(JITObjects::TheJIT->getTargetMachine().createDataLayout());

  // Create a new pass manager attached to it.
  JITObjects::TheFPM = llvm::make_unique<legacy::FunctionPassManager>(AstObjects::TheModule.get());

  // HACK:: removed because not present in the full code listing and because of
  // errors in linking phase (libLLVMTransformUtils)
  // Promote allocas to registers.
  JITObjects::TheFPM->add(createPromoteMemoryToRegisterPass());
  // Do simple "peephole" optimizations and bit-twiddling optzns.
  JITObjects::TheFPM->add(createInstructionCombiningPass());
  // Reassociate expressions.
  JITObjects::TheFPM->add(createReassociatePass());
  // Eliminate Common SubExpressions.
  JITObjects::TheFPM->add(createGVNPass());
  // Simplify the control flow graph (deleting unreachable blocks, etc).
  JITObjects::TheFPM->add(createCFGSimplificationPass());

  JITObjects::TheFPM->doInitialization();
}

Function *getFunction(std::string Name) {
  // First, see if the function has already been added to the current module.
  if (auto *F = AstObjects::TheModule->getFunction(Name))
    return F;

  // If not, check whether we can codegen the declaration from some existing
  // prototype.
  auto FI = JITObjects::FunctionProtos.find(Name);
  if (FI != JITObjects::FunctionProtos.end())
    return FI->second->codegen();

  // If no existing prototype exists, return null.
  return nullptr;
}

}