Merge pull request #466 from SapphireLinXu/lab6

[LAB6] 312553027

Author: YingMuo

lab6/llvm-pass.so.cc

@@ -1,34 +1,110 @@
 #include "llvm/Passes/PassPlugin.h"
 #include "llvm/Passes/PassBuilder.h"
+#include "llvm/IR/Constants.h"
 #include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/GlobalValue.h"
+#include "llvm/Support/raw_ostream.h"
 
-using namespace llvm;
+namespace {
 
-struct LLVMPass : public PassInfoMixin<LLVMPass> {
-  PreservedAnalyses run(Module &M, ModuleAnalysisManager &MAM);
+// Module transformation to modify main function
+class ModuleTransform : PassInfoMixin<ModuleTransform> {
+public:
+  PreservedAnalyses run(llvm::Module& Module, llvm::ModuleAnalysisManager& AM) {
+    // Debug constant value
+    const uint32_t DEBUG_MAGIC = 48763;
+    
+    // Get necessary types
+    auto& Context = Module.getContext();
+    auto* Int32Type = llvm::Type::getInt32Ty(Context);
+    auto* CharPtrType = llvm::Type::getInt8PtrTy(Context);
+    
+    // Create debug function declaration
+    auto* DebugFuncType = llvm::FunctionType::get(
+      llvm::Type::getVoidTy(Context), 
+      {Int32Type}, 
+      false
+    );
+    auto DebugFunction = Module.getOrInsertFunction("debug", DebugFuncType);
+    
+    // Create magic number constant
+    auto* MagicNumber = llvm::ConstantInt::get(Int32Type, DEBUG_MAGIC);
+    
+    // Create string constant
+    auto* HiddenMessage = llvm::ConstantDataArray::getString(
+      Context, 
+      "hayaku... motohayaku!", 
+      true
+    );
+    
+    // Create global variable for the string
+    auto* StringGlobal = new llvm::GlobalVariable(
+      Module,
+      HiddenMessage->getType(),
+      true,
+      llvm::GlobalValue::PrivateLinkage,
+      HiddenMessage,
+      ".str.hayaku"
+    );
+    
+    // Create GEP indices for string pointer
+    auto* ZeroIndex = llvm::ConstantInt::get(Int32Type, 0);
+    llvm::Constant* Indices[2] = {ZeroIndex, ZeroIndex};
+    
+    // Get pointer to string
+    auto* StringPointer = llvm::ConstantExpr::getGetElementPtr(
+      HiddenMessage->getType(), 
+      StringGlobal, 
+      Indices
+    );
+    
+    // Find and instrument main function
+    for (auto& Func : Module) {
+      if (Func.getName() != "main")
+        continue;
+        
+      llvm::errs() << "Found and instrumenting: " << Func.getName() << "\n";
+      
+      // Create builder at entry point
+      llvm::IRBuilder<> Builder(&Func.getEntryBlock().front());
+      
+      // Insert debug call
+      Builder.CreateCall(DebugFunction, {MagicNumber});
+      
+      // Get function args
+      auto Args = Func.arg_begin();
+      auto* ArgCount = Args++;
+      auto* ArgVector = Args;
+      
+      // Modify argv[1] to point to our string
+      auto* SecondArgPtr = Builder.CreateGEP(CharPtrType, ArgVector, 
+                                           llvm::ConstantInt::get(Int32Type, 1));
+      Builder.CreateStore(StringPointer, SecondArgPtr);
+      
+      // Replace all uses of argc with our magic value
+      ArgCount->replaceAllUsesWith(MagicNumber);
+    }
+    
+    // Mark all analyses as invalidated
+    return PreservedAnalyses::none();
+  }
 };
 
-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);
-
-  for (auto &F : M) {
-    errs() << "func: " << F.getName() << "\n";
+} // anonymous namespace
 
-  }
-  return PreservedAnalyses::none();
-}
-
-extern "C" ::llvm::PassPluginLibraryInfo LLVM_ATTRIBUTE_WEAK
-llvmGetPassPluginInfo() {
-  return {LLVM_PLUGIN_API_VERSION, "LLVMPass", "1.0",
-    [](PassBuilder &PB) {
+// Plugin registration
+extern "C" LLVM_ATTRIBUTE_WEAK 
+::llvm::PassPluginLibraryInfo llvmGetPassPluginInfo() {
+  return {
+    LLVM_PLUGIN_API_VERSION,
+    "ModuleInstrumenter",  // plugin name
+    "v1.0",                // plugin version
+    [](llvm::PassBuilder &PB) {
       PB.registerOptimizerLastEPCallback(
-        [](ModulePassManager &MPM, OptimizationLevel OL) {
-          MPM.addPass(LLVMPass());
-        });
-    }};
-}
-
+        [](llvm::ModulePassManager &MPM, llvm::OptimizationLevel Level) {
+          MPM.addPass(ModuleTransform());
+        }
+      );
+    }
+  };
+}