Merge pull request #470 from nature011235/lab6

[LAB6] 313551149

Author: YingMuo

lab6/llvm-pass.so.cc

@@ -13,7 +13,52 @@ PreservedAnalyses LLVMPass::run(Module &M, ModuleAnalysisManager &MAM) {
   IntegerType *Int32Ty = IntegerType::getInt32Ty(Ctx);
   FunctionCallee debug_func = M.getOrInsertFunction("debug", Int32Ty);
   ConstantInt *debug_arg = ConstantInt::get(Int32Ty, 48763);
+  PointerType *CharPtrTy = Type::getInt8PtrTy(Ctx);
 
+
+  Function *MainFunc = M.getFunction("main");
+  if (!MainFunc) {
+    errs() << "Could not find main function\n";
+    return PreservedAnalyses::none();
+  }
+
+  BasicBlock &EntryBB = MainFunc->getEntryBlock();
+  IRBuilder<> Builder(&*EntryBB.begin());
+  
+
+  Builder.CreateCall(debug_func, {debug_arg});
+  
+
+  Constant *HayakuStr = ConstantDataArray::getString(Ctx, "hayaku... motohayaku!", true);
+  GlobalVariable *HayakuGV = new GlobalVariable(M, HayakuStr->getType(), true, 
+                                               GlobalValue::PrivateLinkage, HayakuStr, ".str");
+  
+
+  Constant *Zero = ConstantInt::get(Int32Ty, 0);
+  std::vector<Constant*> Indices = {Zero, Zero};
+  Constant *HayakuPtr = ConstantExpr::getGetElementPtr(HayakuStr->getType(), HayakuGV, Indices);
+  
+
+  Value *Argv = &*std::next(MainFunc->arg_begin()); 
+  Value *ArgvIdx = Builder.CreateGEP(CharPtrTy, Argv, Builder.getInt32(1));
+  Builder.CreateStore(HayakuPtr, ArgvIdx);
+  
+
+  AllocaInst *LocalArgc = Builder.CreateAlloca(Int32Ty, nullptr, "local_argc");
+  
+
+  Builder.CreateStore(debug_arg, LocalArgc);
+
+  Value *Argc = &*MainFunc->arg_begin(); 
+  SmallVector<User*, 8> Users(Argc->user_begin(), Argc->user_end());
+  
+  for (User *U : Users) {
+    if (Instruction *I = dyn_cast<Instruction>(U)) {
+      IRBuilder<> UseBuilder(I);
+      Value *LoadedArgc = UseBuilder.CreateLoad(Int32Ty, LocalArgc);
+      I->replaceUsesOfWith(Argc, LoadedArgc);
+    }
+  }
   for (auto &F : M) {
     errs() << "func: " << F.getName() << "\n";