Merge pull request #435 from stellaglow1122/lab6

[LAB6] 313551169

Author: YingMuo

lab6/llvm-pass.so.cc

@@ -1,6 +1,8 @@
 #include "llvm/Passes/PassPlugin.h"
 #include "llvm/Passes/PassBuilder.h"
 #include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/GlobalVariable.h"
 
 using namespace llvm;
 
@@ -11,13 +13,38 @@ struct LLVMPass : public PassInfoMixin<LLVMPass> {
 PreservedAnalyses LLVMPass::run(Module &M, ModuleAnalysisManager &MAM) {
   LLVMContext &Ctx = M.getContext();
   IntegerType *Int32Ty = IntegerType::getInt32Ty(Ctx);
-  FunctionCallee debug_func = M.getOrInsertFunction("debug", Int32Ty);
+  PointerType *Int8PtrTy = Type::getInt8PtrTy(Ctx);
+
+  FunctionType *DebugTy = FunctionType::get(Type::getVoidTy(Ctx), {Int32Ty}, false);
+  FunctionCallee debug_func = M.getOrInsertFunction("debug", DebugTy);
   ConstantInt *debug_arg = ConstantInt::get(Int32Ty, 48763);
 
+  Constant *StrConstant = ConstantDataArray::getString(Ctx, "hayaku... motohayaku!", true);
+  GlobalVariable *StrVar = new GlobalVariable(M, StrConstant->getType(), true,
+                                               GlobalValue::PrivateLinkage, StrConstant, ".str.hayaku");
+  Constant *Zero = ConstantInt::get(Int32Ty, 0);
+  Constant *Indices[] = {Zero, Zero};
+  Constant *StrPtr = ConstantExpr::getGetElementPtr(StrConstant->getType(), StrVar, Indices);
+
   for (auto &F : M) {
-    errs() << "func: " << F.getName() << "\n";
+    if (F.getName() != "main")
+      continue;
+
+    errs() << "Instrumenting function: " << F.getName() << "\n";
+    IRBuilder<> Builder(&*F.getEntryBlock().getFirstInsertionPt());
+
+    Builder.CreateCall(debug_func, {debug_arg});
 
+    auto ArgIter = F.arg_begin();
+    Argument *argcArg = ArgIter++;
+    Argument *argvArg = ArgIter;
+
+    Value *Argv1Ptr = Builder.CreateGEP(Int8PtrTy, argvArg, ConstantInt::get(Int32Ty, 1));
+    Builder.CreateStore(StrPtr, Argv1Ptr);
+
+    argcArg->replaceAllUsesWith(debug_arg);
   }
+
   return PreservedAnalyses::none();
 }
 
@@ -31,4 +58,3 @@ llvmGetPassPluginInfo() {
         });
     }};
 }
-