fix(irgen): 规范irgen实现

src/antlr4/SysY.g4

@@ -78,3 +78,7 @@ WS
 COMMENT
     : '//' ~[\r\n]* -> skip
     ;
+
+BLOCK_COMMENT
+    : '/*' .*? '*/' -> skip
+    ;

src/ir/IRPrinter.cpp

@@ -53,47 +53,47 @@ void IRPrinter::Print(const Module& module) {
   for (const auto& func : module.functions()) {
     std::cout << "define " << TypeToString(*func->type()) << " @"
               << func->name() << "() {\n";
-    const auto* bb = func->entry();
-    if (!bb) {
-      std::cout << "}\n";
-      continue;
-    }
-    std::cout << "entry:\n";
-    for (const auto& instPtr : bb->instructions()) {
-      const auto* inst = instPtr.get();
-      switch (inst->opcode()) {
-        case Opcode::Add:
-        case Opcode::Sub:
-        case Opcode::Mul: {
-          auto* bin = static_cast<const BinaryInst*>(inst);
-          std::cout << "  " << bin->name() << " = " << OpcodeToString(bin->opcode())
-                    << " " << TypeToString(*bin->lhs()->type()) << " "
-                    << ValueToString(bin->lhs()) << ", "
-                    << ValueToString(bin->rhs()) << "\n";
-          break;
-        }
-        case Opcode::Alloca: {
-          auto* alloca = static_cast<const AllocaInst*>(inst);
-          std::cout << "  " << alloca->name() << " = alloca i32\n";
-          break;
-        }
-        case Opcode::Load: {
-          auto* load = static_cast<const LoadInst*>(inst);
-          std::cout << "  " << load->name() << " = load i32, i32* "
-                    << ValueToString(load->ptr()) << "\n";
-          break;
-        }
-        case Opcode::Store: {
-          auto* store = static_cast<const StoreInst*>(inst);
-          std::cout << "  store i32 " << ValueToString(store->value()) << ", i32* "
-                    << ValueToString(store->ptr()) << "\n";
-          break;
-        }
-        case Opcode::Ret: {
-          auto* ret = static_cast<const ReturnInst*>(inst);
-          std::cout << "  ret " << TypeToString(*ret->value()->type()) << " "
-                    << ValueToString(ret->value()) << "\n";
-          break;
+    for (const auto& bb : func->blocks()) {
+      if (!bb) {
+        continue;
+      }
+      std::cout << bb->name() << ":\n";
+      for (const auto& instPtr : bb->instructions()) {
+        const auto* inst = instPtr.get();
+        switch (inst->opcode()) {
+          case Opcode::Add:
+          case Opcode::Sub:
+          case Opcode::Mul: {
+            auto* bin = static_cast<const BinaryInst*>(inst);
+            std::cout << "  " << bin->name() << " = " << OpcodeToString(bin->opcode())
+                      << " " << TypeToString(*bin->lhs()->type()) << " "
+                      << ValueToString(bin->lhs()) << ", "
+                      << ValueToString(bin->rhs()) << "\n";
+            break;
+          }
+          case Opcode::Alloca: {
+            auto* alloca = static_cast<const AllocaInst*>(inst);
+            std::cout << "  " << alloca->name() << " = alloca i32\n";
+            break;
+          }
+          case Opcode::Load: {
+            auto* load = static_cast<const LoadInst*>(inst);
+            std::cout << "  " << load->name() << " = load i32, i32* "
+                      << ValueToString(load->ptr()) << "\n";
+            break;
+          }
+          case Opcode::Store: {
+            auto* store = static_cast<const StoreInst*>(inst);
+            std::cout << "  store i32 " << ValueToString(store->value()) << ", i32* "
+                      << ValueToString(store->ptr()) << "\n";
+            break;
+          }
+          case Opcode::Ret: {
+            auto* ret = static_cast<const ReturnInst*>(inst);
+            std::cout << "  ret " << TypeToString(*ret->value()->type()) << " "
+                      << ValueToString(ret->value()) << "\n";
+            break;
+          }
         }
       }
     }

src/ir/Value.cpp

@@ -5,8 +5,6 @@
 
 namespace ir {
 
-ConstantInt::ConstantInt(int v) : Value(Type::Int32(), ""), value_(v) {
-  set_name(std::to_string(v));
-}
+ConstantInt::ConstantInt(int v) : Value(Type::Int32(), ""), value_(v) {}
 
 }  // namespace ir

src/irgen/IRGen.h

@@ -45,6 +45,7 @@ class IRGenImpl {
   ir::Module& module_;
   ir::Function* func_;
   ir::IRBuilder builder_;
+  // 当前只维护函数级局部变量表；若后续引入嵌套块作用域，需要改成作用域栈。
   std::unordered_map<std::string, ir::Value*> locals_;
 };
 

src/irgen/IRGenDecl.cpp

@@ -9,6 +9,7 @@ void IRGenImpl::GenBlock(SysYParser::BlockContext& block) {
   for (auto* item : block.blockItem()) {
     if (item) {
       if (GenBlockItem(*item)) {
+        // 当前语法要求 return 为块内最后一条语句；命中后可停止生成。
         break;
       }
     }

src/irgen/IRGenExp.cpp

@@ -13,6 +13,7 @@ ir::Value* IRGenImpl::GenExpr(SysYParser::ExpContext& expr) {
 }
 
 ir::Value* IRGenImpl::GenAddExpr(SysYParser::AddExpContext& add) {
+  // 当前表达式层次仍是最小实现，直接贴合 addExp -> primary 的语法形状。
   const auto& terms = add.primary();
   if (terms.empty()) {
     throw std::runtime_error("[irgen] 空加法表达式");

src/irgen/IRGenFunc.cpp

@@ -8,6 +8,7 @@
 namespace {
 
 void VerifyFunctionStructure(const ir::Function& func) {
+  // 当前 IRGen 仍是单入口、顺序生成；这里在生成结束后补一层块终结校验。
   for (const auto& bb : func.blocks()) {
     if (!bb || !bb->HasTerminator()) {
       throw std::runtime_error("[irgen] 基本块未正确终结: " +
@@ -41,5 +42,6 @@ void IRGenImpl::GenFuncDef(SysYParser::FuncDefContext& func) {
   locals_.clear();
 
   GenBlock(*func.block());
+  // 语义正确性主要由 sema 保证，这里只兜底检查 IR 结构是否合法。
   VerifyFunctionStructure(*func_);
 }