[LAB6] 313560007

lab6/llvm-pass.so.cc

@@ -1,34 +1,88 @@
 #include "llvm/Passes/PassPlugin.h"
 #include "llvm/Passes/PassBuilder.h"
 #include "llvm/IR/IRBuilder.h"
-
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Constants.h"
 using namespace llvm;
 
-struct LLVMPass : public PassInfoMixin<LLVMPass> {
-  PreservedAnalyses run(Module &M, ModuleAnalysisManager &MAM);
-};
+namespace {
+
+struct Lab6FinalPass : PassInfoMixin<Lab6FinalPass> {
+  PreservedAnalyses run(Module &M, ModuleAnalysisManager &) {
+    LLVMContext &C = M.getContext();
+    auto *i32 = Type::getInt32Ty(C);
+    auto *i8ptr = Type::getInt8PtrTy(C);
+
+    // 宣告 debug 函數與 48763 常數
+    auto debugTy = FunctionType::get(Type::getVoidTy(C), {i32}, false);
+    auto debugFn = M.getOrInsertFunction("debug", debugTy);
+    auto const48763 = ConstantInt::get(i32, 48763);
+
+    // 建立常數字串 "hayaku... motohayaku!"
+    auto strConst = ConstantDataArray::getString(C, "hayaku... motohayaku!", true);
+    auto *gstr = new GlobalVariable(M, strConst->getType(), true,
+                                    GlobalValue::PrivateLinkage, strConst, "haya_str");
+    auto strPtr = ConstantExpr::getBitCast(gstr, i8ptr);
+
+    // 找到 main 函式
+    Function *main = M.getFunction("main");
+    if (!main) return PreservedAnalyses::all();
+
+    // IRBuilder 插入點設在 entry block 開頭
+    IRBuilder<> B(&*main->getEntryBlock().getFirstInsertionPt());
 
-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);
+    // 呼叫 debug(48763)
+    B.CreateCall(debugFn, const48763);
 
-  for (auto &F : M) {
-    errs() << "func: " << F.getName() << "\n";
+    // 抓取 main 的參數
+    Argument *argc = nullptr, *argv = nullptr;
+    auto it = main->arg_begin();
+    if (it != main->arg_end()) argc = it++;
+    if (it != main->arg_end()) argv = it;
 
+    // 覆寫 argv[1] 的記憶體：argv[1] = strPtr
+    Value *idx[] = { ConstantInt::get(i32, 1) };
+    Value *argv1Ptr = B.CreateInBoundsGEP(i8ptr, argv, idx);
+    B.CreateStore(strPtr, argv1Ptr);
+
+    // 遍歷整個函數，修改 argc 為常數，並處理 strcmp
+    for (auto &BB : *main) {
+      for (auto &I : BB) {
+        // 修改使用 argc 的地方
+        for (unsigned i = 0; i < I.getNumOperands(); ++i) {
+          if (I.getOperand(i) == argc) {
+            I.setOperand(i, const48763);
+          }
+        }
+
+        // 如果遇到 strcmp(argv[1], ...) 則強制修改 argv[1] 為我們的字串
+        if (auto *call = dyn_cast<CallInst>(&I)) {
+          if (Function *callee = call->getCalledFunction()) {
+            if (callee->getName() == "strcmp" && call->arg_size() >= 2) {
+              call->setArgOperand(0, strPtr);
+            }
+          }
+        }
+      }
+    }
+
+    return PreservedAnalyses::none();
   }
-  return PreservedAnalyses::none();
-}
+};
+
+} // namespace
 
-extern "C" ::llvm::PassPluginLibraryInfo LLVM_ATTRIBUTE_WEAK
-llvmGetPassPluginInfo() {
-  return {LLVM_PLUGIN_API_VERSION, "LLVMPass", "1.0",
+// 註冊 Pass 到 New Pass Manager
+extern "C" LLVM_ATTRIBUTE_WEAK ::llvm::PassPluginLibraryInfo llvmGetPassPluginInfo() {
+  return {
+    LLVM_PLUGIN_API_VERSION, "Lab6FinalPass", "v1.0",
     [](PassBuilder &PB) {
-      PB.registerOptimizerLastEPCallback(
-        [](ModulePassManager &MPM, OptimizationLevel OL) {
-          MPM.addPass(LLVMPass());
+      PB.registerPipelineStartEPCallback(
+        [](ModulePassManager &MPM, OptimizationLevel) {
+          MPM.addPass(Lab6FinalPass());
         });
-    }};
+    }
+  };
 }
-