Fix various build issues with latest llvm18

Latest llvm18 cannot build with bcc now. There are 3 issues:
  - In IRBuilder, getInt8PtrTy() renamed to getPtrTy().
  - Newly introdeuced clang library libclangAPINotes.a.
  - Newly introduced llvm library libLLVMFrontendDriver.a

This patch fixed the above three issues so bcc can be built
with llvm18 successfully. I then tried a few bcc tools and
they all works fine.

Signed-off-by: Yonghong Song <yonghong.song@linux.dev>

Author: Yonghong Song

CMakeLists.txt

@@ -163,6 +163,10 @@ if(NOT PYTHON_ONLY)
       find_library(libclangSupport NAMES clangSupport clang-cpp HINTS ${CLANG_SEARCH})
     endif()
 
+    if(${LLVM_PACKAGE_VERSION} VERSION_EQUAL 18 OR ${LLVM_PACKAGE_VERSION} VERSION_GREATER 18)
+      find_library(libclangAPINotes NAMES clangAPINotes clang-cpp HINTS ${CLANG_SEARCH})
+    endif()
+
     find_library(libclang-shared libclang-cpp.so HINTS ${CLANG_SEARCH})
 
     if(libclangBasic STREQUAL "libclangBasic-NOTFOUND")

cmake/clang_libs.cmake

@@ -28,6 +28,9 @@ endif()
 if (${LLVM_PACKAGE_VERSION} VERSION_EQUAL 16 OR ${LLVM_PACKAGE_VERSION} VERSION_GREATER 16)
   list(APPEND llvm_raw_libs frontendhlsl)
 endif()
+if (${LLVM_PACKAGE_VERSION} VERSION_EQUAL 18 OR ${LLVM_PACKAGE_VERSION} VERSION_GREATER 18)
+  list(APPEND llvm_raw_libs frontenddriver)
+endif()
 
 llvm_map_components_to_libnames(_llvm_libs ${llvm_raw_libs})
 llvm_expand_dependencies(llvm_libs ${_llvm_libs})
@@ -60,6 +63,10 @@ list(APPEND clang_libs
   list(APPEND clang_libs ${libclangSupport})
 # endif()
 
+if (${LLVM_PACKAGE_VERSION} VERSION_EQUAL 18 OR ${LLVM_PACKAGE_VERSION} VERSION_GREATER 18)
+  list(APPEND clang_libs ${libclangAPINotes})
+endif()
+
 list(APPEND clang_libs
   ${libclangBasic})
 endif()

src/cc/bpf_module_rw_engine.cc

@@ -82,7 +82,11 @@ static void debug_printf(Module *mod, IRBuilder<> &B, const string &fmt, vector<
   args.insert(args.begin(), B.getInt64((uintptr_t)stderr));
   Function *fprintf_fn = mod->getFunction("fprintf");
   if (!fprintf_fn) {
+#if LLVM_VERSION_MAJOR >= 18
+    vector<Type *> fprintf_fn_args({B.getInt64Ty(), B.getPtrTy()});
+#else
     vector<Type *> fprintf_fn_args({B.getInt64Ty(), B.getInt8PtrTy()});
+#endif
     FunctionType *fprintf_fn_type = FunctionType::get(B.getInt32Ty(), fprintf_fn_args, /*isvarArg=*/true);
     fprintf_fn = Function::Create(fprintf_fn_type, GlobalValue::ExternalLinkage, "fprintf", mod);
     fprintf_fn->setCallingConv(CallingConv::C);
@@ -267,7 +271,11 @@ string BPFModule::make_reader(Module *mod, Type *type) {
   IRBuilder<> B(*ctx_);
 
   FunctionType *sscanf_fn_type = FunctionType::get(
+#if LLVM_VERSION_MAJOR >= 18
+      B.getInt32Ty(), {B.getPtrTy(), B.getPtrTy()}, /*isVarArg=*/true);
+#else
       B.getInt32Ty(), {B.getInt8PtrTy(), B.getInt8PtrTy()}, /*isVarArg=*/true);
+#endif
   Function *sscanf_fn = mod->getFunction("sscanf");
   if (!sscanf_fn) {
     sscanf_fn = Function::Create(sscanf_fn_type, GlobalValue::ExternalLinkage,
@@ -277,7 +285,11 @@ string BPFModule::make_reader(Module *mod, Type *type) {
   }
 
   string name = "reader" + std::to_string(readers_.size());
+#if LLVM_VERSION_MAJOR >= 18
+  vector<Type *> fn_args({B.getPtrTy(), PointerType::getUnqual(type)});
+#else
   vector<Type *> fn_args({B.getInt8PtrTy(), PointerType::getUnqual(type)});
+#endif
   FunctionType *fn_type = FunctionType::get(B.getInt32Ty(), fn_args, /*isVarArg=*/false);
   Function *fn =
       Function::Create(fn_type, GlobalValue::ExternalLinkage, name, mod);
@@ -293,7 +305,11 @@ string BPFModule::make_reader(Module *mod, Type *type) {
   B.SetInsertPoint(label_entry);
 
   Value *nread = B.CreateAlloca(B.getInt32Ty());
+#if LLVM_VERSION_MAJOR >= 18
+  Value *sptr = B.CreateAlloca(B.getPtrTy());
+#else
   Value *sptr = B.CreateAlloca(B.getInt8PtrTy());
+#endif
   map<string, Value *> locals{{"nread", nread}, {"sptr", sptr}};
   B.CreateStore(arg_in, sptr);
   vector<Value *> args({nullptr, nullptr});
@@ -337,7 +353,11 @@ string BPFModule::make_writer(Module *mod, Type *type) {
   IRBuilder<> B(*ctx_);
 
   string name = "writer" + std::to_string(writers_.size());
+#if LLVM_VERSION_MAJOR >= 18
+  vector<Type *> fn_args({B.getPtrTy(), B.getInt64Ty(), PointerType::getUnqual(type)});
+#else
   vector<Type *> fn_args({B.getInt8PtrTy(), B.getInt64Ty(), PointerType::getUnqual(type)});
+#endif
   FunctionType *fn_type = FunctionType::get(B.getInt32Ty(), fn_args, /*isVarArg=*/false);
   Function *fn =
       Function::Create(fn_type, GlobalValue::ExternalLinkage, name, mod);
@@ -369,7 +389,11 @@ string BPFModule::make_writer(Module *mod, Type *type) {
   if (0)
     debug_printf(mod, B, "%d %p %p\n", vector<Value *>({arg_len, arg_out, arg_in}));
 
+#if LLVM_VERSION_MAJOR >= 18
+  vector<Type *> snprintf_fn_args({B.getPtrTy(), B.getInt64Ty(), B.getPtrTy()});
+#else
   vector<Type *> snprintf_fn_args({B.getInt8PtrTy(), B.getInt64Ty(), B.getInt8PtrTy()});
+#endif
   FunctionType *snprintf_fn_type = FunctionType::get(B.getInt32Ty(), snprintf_fn_args, /*isVarArg=*/true);
   Function *snprintf_fn = mod->getFunction("snprintf");
   if (!snprintf_fn)