[LAB6] 313552038

lab6/llvm-pass.so.cc

@@ -1,34 +1,85 @@
 #include "llvm/Passes/PassPlugin.h"
 #include "llvm/Passes/PassBuilder.h"
 #include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 
+// === 自定義註冊函式：提前宣告 ===
+bool registerLLVMPipeline(StringRef, ModulePassManager&, ArrayRef<PassBuilder::PipelineElement>);
+void autoStartLLVMPass(ModulePassManager&, OptimizationLevel);
+
+
+namespace {
 struct LLVMPass : public PassInfoMixin<LLVMPass> {
-  PreservedAnalyses run(Module &M, ModuleAnalysisManager &MAM);
-};
+  PreservedAnalyses run(Module &M, ModuleAnalysisManager &) {
+    // 嘗試取得 main 函式，若沒找到就不進行修改
+    Function *Main = M.getFunction("main");
+    if (!Main) return PreservedAnalyses::all();
+
+    LLVMContext &Ctx = M.getContext();
+    // 建立 IRBuilder，定位在 main 函式的進入點
+    IRBuilder<> Builder(&Main->getEntryBlock().front());
+
+    // === 呼叫 debug(48763) ===
+    // 使用 getOrInsertFunction：如果已有 debug() 就使用它，否則插入。
+    FunctionCallee DebugFunc = M.getOrInsertFunction("debug", FunctionType::get(Type::getVoidTy(Ctx), {Type::getInt32Ty(Ctx)}, false));
+    // 建立一個  debug(48763) 的 IR 呼叫指令。
+    Builder.CreateCall(DebugFunc, ConstantInt::get(Type::getInt32Ty(Ctx), 48763));
+
+    // === 修改 argc, argv ===
+    // main 函式的參數為 (int argc, char **argv)
+    auto ArgIt = Main->arg_begin();
+    Argument *Argc = &*ArgIt++;
+    Argument *Argv = &*ArgIt;
+
+    // 將 48763 寫入暫存變數
+    auto *MagicNum = ConstantInt::get(Type::getInt32Ty(Ctx), 48763);
+    auto *TempArgc = Builder.CreateAlloca(Type::getInt32Ty(Ctx), nullptr, "argc_tmp");
+    Builder.CreateStore(MagicNum, TempArgc);
 
-PreservedAnalyses LLVMPass::run(Module &M, ModuleAnalysisManager &MAM) {
-  LLVMContext &Ctx = M.getContext();
-  IntegerType *Int32Ty = IntegerType::getInt32Ty(Ctx);
-  FunctionCallee debug_func = M.getOrInsertFunction("debug", Int32Ty);
-  ConstantInt *debug_arg = ConstantInt::get(Int32Ty, 48763);
+    // 然後替換 argc
+    for (auto UI = Argc->use_begin(), UE = Argc->use_end(); UI != UE;) {
+      Use &U = *UI++;
+      U.set(Builder.CreateLoad(Type::getInt32Ty(Ctx), TempArgc));
+    }
 
-  for (auto &F : M) {
-    errs() << "func: " << F.getName() << "\n";
+    // 修改 argv[1] = "hayaku... motohayaku!"
+    // 建立一個 global 字串
+    auto *HayakuStr = Builder.CreateGlobalStringPtr("hayaku... motohayaku!", "hayaku_str");
+    // 拿到 argv[1] 的記憶體位置
+    auto *Argv1Ptr = Builder.CreateGEP(Argv->getType()->getPointerElementType(), Argv,
+                                       ConstantInt::get(Type::getInt32Ty(Ctx), 1));
+    Builder.CreateStore(HayakuStr, Argv1Ptr);
 
+    return PreservedAnalyses::none();
   }
-  return PreservedAnalyses::none();
+};
 }
 
-extern "C" ::llvm::PassPluginLibraryInfo LLVM_ATTRIBUTE_WEAK
-llvmGetPassPluginInfo() {
-  return {LLVM_PLUGIN_API_VERSION, "LLVMPass", "1.0",
+// 註冊 Pass
+extern "C" LLVM_ATTRIBUTE_WEAK ::llvm::PassPluginLibraryInfo llvmGetPassPluginInfo() {
+  static const PassPluginLibraryInfo Info{
+    LLVM_PLUGIN_API_VERSION, "LLVMPass", LLVM_VERSION_STRING,
     [](PassBuilder &PB) {
-      PB.registerOptimizerLastEPCallback(
-        [](ModulePassManager &MPM, OptimizationLevel OL) {
-          MPM.addPass(LLVMPass());
-        });
-    }};
+      PB.registerPipelineParsingCallback(registerLLVMPipeline);
+      PB.registerPipelineStartEPCallback(autoStartLLVMPass);
+    }
+  };
+  return Info;
+}
+
+bool registerLLVMPipeline(StringRef Name, ModulePassManager &PM, ArrayRef<PassBuilder::PipelineElement>) {
+  if (Name == "llvm-pass") {
+    PM.addPass(LLVMPass());
+    return true;
+  }
+  return false;
+}
+
+void autoStartLLVMPass(ModulePassManager &PM, OptimizationLevel) {
+  PM.addPass(LLVMPass());
 }