1 files changed, 69 insertions, 0 deletions
diff --git a/node/FunctionNode.cc b/node/FunctionNode.cc
new file mode 100644
index 0000000..3346db0
--- /dev/null
+++ b/node/FunctionNode.cc
@@ -0,0 +1,69 @@
+#include <memory>
+#include <vector>
+
+#include <llvm/IR/IRBuilder.h>
+
+#include "DeclNode.hh"
+#include "FunctionNode.hh"
+
+namespace pcc {
+FunctionNode::FunctionNode(
+    Context* context, std::string name, std::list<Declaration> arguments,
+    std::list<std::shared_ptr<BaseNode>> LocalDeclarations,
+    std::shared_ptr<Type> type, std::shared_ptr<StatementListNode> body)
+    : BaseNode(context)
+    , name_(name)
+    , arguments_(arguments)
+    , LocalDeclarations_(LocalDeclarations)
+    , type_(type)
+    , locals_(context->GetGlobals())
+    , body_(body) {
+    for (auto& decl : LocalDeclarations_) {
+        std::shared_ptr<VarDeclNode> VarDecl =
+            std::dynamic_pointer_cast<VarDeclNode>(decl);
+        if (VarDecl != nullptr) {
+            // set the inherited attribute
+            VarDecl->SetScope(&locals_);
+        }
+    }
+}
+
+Value FunctionNode::CodeGen() {
+    llvm::Module* module = context_->GetModule();
+    llvm::IRBuilder<>* builder = context_->GetBuilder();
+    std::vector<llvm::Type*> params(arguments_.size());
+    std::transform(arguments_.cbegin(), arguments_.cend(), params.begin(),
+                   [](const Declaration& decl) {
+                       return std::get<1>(decl)->GetLLVMType();
+                   });
+    llvm::Type* type =
+        llvm::FunctionType::get(type_->GetLLVMType(), params, false);
+    llvm::FunctionCallee f = module->getOrInsertFunction(name_, type);
+    llvm::Function* function = llvm::cast<llvm::Function>(f.getCallee());
+    function->setCallingConv(llvm::CallingConv::C);
+    llvm::BasicBlock* block =
+        llvm::BasicBlock::Create(GlobalLLVMContext, name_, function);
+    builder->SetInsertPoint(block);
+    // alloc arguments
+    llvm::Function::arg_iterator ArgIt;
+    for (auto& arg : arguments_) {
+        Value ArgValue = builder->CreateAlloca(std::get<1>(arg)->GetLLVMType());
+        builder->CreateStore(ArgIt++, ArgValue);
+        locals_.Add(std::get<0>(arg), {std::get<1>(arg), ArgValue});
+    }
+    // alloc local variables
+    for (auto& decl : LocalDeclarations_) {
+        decl->CodeGen();
+    }
+    // create a variable with the same name as the function for return value
+    Value rv = builder->CreateAlloca(type_->GetLLVMType());
+    locals_.Add(name_, {type_, rv});
+    // push the function scope variables
+    context_->PushScope(&locals_);
+    body_->CodeGen();
+    builder->CreateRet(rv);
+    context_->PopScope();
+    return nullptr;
+}
+
+} // namespace pcc