Add a C++ counterpart of the sum example.

Author: maleadt

examples/sum.cpp

@@ -0,0 +1,56 @@
+// C++ counterpart of sum.jl
+
+#include <string>
+#include <vector>
+
+#include <llvm/ExecutionEngine/ExecutionEngine.h>
+#include <llvm/ExecutionEngine/GenericValue.h>
+#include <llvm/ExecutionEngine/Interpreter.h>
+#include <llvm/IR/IRBuilder.h>
+#include <llvm/IR/LLVMContext.h>
+#include <llvm/IR/Module.h>
+#include <llvm/IR/Verifier.h>
+
+static llvm::LLVMContext context;
+
+int main(int argc, char *argv[]) {
+  std::unique_ptr<llvm::Module> mod =
+      llvm::make_unique<llvm::Module>("module", context);
+
+  auto T_int32 = llvm::IntegerType::get(context, 32);
+  auto fun_type = llvm::FunctionType::get(T_int32, {T_int32, T_int32}, false);
+  auto sum = llvm::Function::Create(fun_type, llvm::Function::ExternalLinkage,
+                                    "sum", mod.get());
+
+  // generate IR
+  llvm::IRBuilder<> builder(context);
+  {
+    auto *entry = llvm::BasicBlock::Create(context, "entry", sum);
+    builder.SetInsertPoint(entry);
+
+    auto args = sum->arg_begin();
+    llvm::Value *arg1 = &(*args);
+    args = std::next(args);
+    llvm::Value *arg2 = &(*args);
+    auto *tmp = builder.CreateAdd(arg1, arg2, "tmp");
+    builder.CreateRet(tmp);
+
+    mod->dump();
+    verifyFunction(*sum);
+  }
+
+  // execute
+  auto engine = llvm::EngineBuilder(std::move(mod))
+                    .setEngineKind(llvm::EngineKind::Interpreter)
+                    .create();
+  {
+    std::vector<llvm::GenericValue> args(2);
+    args[0].IntVal = llvm::APInt(32, 1, /*isSigned=*/true);
+    args[1].IntVal = llvm::APInt(32, 2, /*isSigned=*/true);
+
+    auto res = engine->runFunction(sum, args);
+    res.IntVal.dump();
+  }
+
+  return 0;
+}