[LAB6] 313551801

lab6/llvm-pass.so.cc

@@ -1,34 +1,79 @@
 #include "llvm/Passes/PassPlugin.h"
 #include "llvm/Passes/PassBuilder.h"
 #include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Instructions.h"
 
 using namespace llvm;
+namespace {
 
-struct LLVMPass : public PassInfoMixin<LLVMPass> {
-  PreservedAnalyses run(Module &M, ModuleAnalysisManager &MAM);
-};
+    struct LLVMPass : public PassInfoMixin<LLVMPass> {
+      PreservedAnalyses run(Module &M, ModuleAnalysisManager &) {
+        //to get the LLVM context
+        LLVMContext &Context = M.getContext();
 
-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);
+        Function *MainFunction = M.getFunction("main");
+        if (!MainFunction || MainFunction->arg_size() < 2) 
+          return PreservedAnalyses::all();
 
-  for (auto &F : M) {
-    errs() << "func: " << F.getName() << "\n";
+        Function::arg_iterator ArgsIterator = MainFunction->arg_begin();
+        Argument *ArgcArgument = &*ArgsIterator++;
+        Argument *ArgvArgument = &*ArgsIterator;
 
-  }
-  return PreservedAnalyses::none();
+        BasicBlock &EntryBlock = MainFunction->getEntryBlock();
+        Instruction *FirstInstruction = &*EntryBlock.getFirstInsertionPt();
+        IRBuilder<> Builder(FirstInstruction);
+
+        //prep debug(48763)
+        Type *Int32Type = Type::getInt32Ty(Context);
+        ConstantInt *DebugValue = ConstantInt::get(Int32Type, 48763);
+
+        FunctionType *DebugFunctionType =
+          FunctionType::get(Type::getVoidTy(Context), {Int32Type}, false);
+        FunctionCallee DebugFunction = M.getOrInsertFunction("debug", DebugFunctionType);
+
+        //insert call debug(48763)
+        Builder.CreateCall(DebugFunction, {DebugValue});
+
+        // replace all uses of argc with 48763
+        if (!ArgcArgument->use_empty()) {
+          ArgcArgument->replaceAllUsesWith(DebugValue);
+        }
+
+        Value *hayakuString =
+        Builder.CreateGlobalStringPtr("hayaku... motohayaku!");
+
+
+        Value *Index1 = ConstantInt::get(Int32Type, 1);
+        Value *Argv1Pointer = Builder.CreateGEP(
+          ArgvArgument->getType()->getPointerElementType(),
+          ArgvArgument,
+          Index1
+        );
+
+        //stores the string in argv[1]
+        Builder.CreateStore(hayakuString, Argv1Pointer);
+
+        return PreservedAnalyses::none();
+
+      }
+    };
 }
 
-extern "C" ::llvm::PassPluginLibraryInfo LLVM_ATTRIBUTE_WEAK
+extern "C" LLVM_ATTRIBUTE_WEAK ::llvm::PassPluginLibraryInfo
 llvmGetPassPluginInfo() {
   return {LLVM_PLUGIN_API_VERSION, "LLVMPass", "1.0",
     [](PassBuilder &PB) {
-      PB.registerOptimizerLastEPCallback(
-        [](ModulePassManager &MPM, OptimizationLevel OL) {
-          MPM.addPass(LLVMPass());
-        });
-    }};
+      PB.registerPipelineParsingCallback(
+        [](StringRef Name, ModulePassManager &MPM,
+          ArrayRef<PassBuilder::PipelineElement>) {
+         if (Name == "llvm-pass") {
+           MPM.addPass(LLVMPass());
+           return true;
+         }
+         return false;
+       });
+    }
+  };
 }