forked from NUDT-compiler/nudt-compiler-cpp
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96 lines
2.7 KiB
96 lines
2.7 KiB
#include "irgen/IRGen.h"
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#include <memory>
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#include <stdexcept>
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#include <string>
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#include <unordered_map>
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#include <utility>
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#include <vector>
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#include "ast/AstNodes.h"
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#include "ir/IR.h"
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namespace {
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class IRGenImpl {
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public:
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explicit IRGenImpl(ir::Module& module)
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: module_(module),
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func_(module_.CreateFunction("main")),
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builder_(func_->entry()) {}
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void Gen(const ast::CompUnit& ast) {
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if (!ast.func || !ast.func->body) {
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throw std::runtime_error("AST 不完整：缺少 main 定义");
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}
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GenBlock(*ast.func->body);
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}
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std::unique_ptr<ir::Module> TakeModule() {
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return std::make_unique<ir::Module>(std::move(module_));
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}
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private:
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void GenBlock(const ast::Block& block) {
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for (const auto& decl : block.varDecls) {
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ir::Value* init = nullptr;
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if (decl->init) {
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init = GenExpr(*decl->init);
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} else {
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const_pool_.push_back(std::make_unique<ir::ConstantInt>(0));
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init = const_pool_.back().get();
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}
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locals_[decl->name] = init;
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}
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for (const auto& stmt : block.stmts) {
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if (auto ret = dynamic_cast<ast::ReturnStmt*>(stmt.get())) {
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ir::Value* v = GenExpr(*ret->value);
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builder_.CreateRet(v);
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}
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}
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}
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ir::Value* GenExpr(const ast::Expr& expr) {
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if (auto num = dynamic_cast<const ast::NumberExpr*>(&expr)) {
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const_pool_.push_back(std::make_unique<ir::ConstantInt>(num->value));
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return const_pool_.back().get();
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}
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if (auto var = dynamic_cast<const ast::VarExpr*>(&expr)) {
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auto it = locals_.find(var->name);
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if (it == locals_.end()) {
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throw std::runtime_error("变量未找到: " + var->name);
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}
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return it->second;
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}
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if (auto bin = dynamic_cast<const ast::BinaryExpr*>(&expr)) {
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auto* lhs = GenExpr(*bin->lhs);
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auto* rhs = GenExpr(*bin->rhs);
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std::string name = "%t" + std::to_string(temp_index_++);
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if (bin->op == ast::BinaryOp::Add) {
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return builder_.CreateBinary(ir::Opcode::Add, lhs, rhs, name);
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}
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if (bin->op == ast::BinaryOp::Sub) {
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// 当前子集只需要加法，减法复用 add 但保留分支，便于扩展
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return builder_.CreateBinary(ir::Opcode::Add, lhs, rhs, name);
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}
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}
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throw std::runtime_error("不支持的表达式类型");
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}
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ir::Module& module_;
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ir::Function* func_;
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ir::IRBuilder builder_;
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std::unordered_map<std::string, ir::Value*> locals_;
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std::vector<std::unique_ptr<ir::ConstantInt>> const_pool_;
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int temp_index_ = 0;
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};
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} // namespace
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std::unique_ptr<ir::Module> GenerateIR(const ast::CompUnit& ast) {
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auto module = std::make_unique<ir::Module>();
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IRGenImpl gen(*module);
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gen.Gen(ast);
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return module;
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}
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