/* * Copyright (c) 2015 PLUMgrid, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include <map> #include <string> #include <algorithm> #include <fcntl.h> #include <ftw.h> #include <map> #include <stdio.h> #include <string> #include <sys/stat.h> #include <sys/utsname.h> #include <unistd.h> #include <vector> #include <linux/bpf.h> #include <clang/Basic/FileManager.h> #include <clang/Basic/TargetInfo.h> #include <clang/CodeGen/BackendUtil.h> #include <clang/CodeGen/CodeGenAction.h> #include <clang/Driver/Compilation.h> #include <clang/Driver/Driver.h> #include <clang/Driver/Job.h> #include <clang/Driver/Tool.h> #include <clang/Frontend/CompilerInstance.h> #include <clang/Frontend/CompilerInvocation.h> #include <clang/Frontend/FrontendActions.h> #include <clang/Frontend/FrontendDiagnostic.h> #include <clang/Frontend/TextDiagnosticPrinter.h> #include <clang/FrontendTool/Utils.h> #include <llvm/IR/Module.h> #include "common.h" #include "exception.h" #include "exported_files.h" #include "kbuild_helper.h" #include "b_frontend_action.h" #include "tp_frontend_action.h" #include "loader.h" using std::map; using std::string; using std::unique_ptr; using std::vector; namespace ebpf { map<string, unique_ptr<llvm::MemoryBuffer>> ClangLoader::remapped_files_; ClangLoader::ClangLoader(llvm::LLVMContext *ctx, unsigned flags) : ctx_(ctx), flags_(flags) { if (remapped_files_.empty()) { for (auto f : ExportedFiles::headers()) remapped_files_[f.first] = llvm::MemoryBuffer::getMemBuffer(f.second); } } ClangLoader::~ClangLoader() {} int ClangLoader::parse(unique_ptr<llvm::Module> *mod, unique_ptr<vector<TableDesc>> *tables, const string &file, bool in_memory, const char *cflags[], int ncflags) { using namespace clang; string main_path = "/virtual/main.c"; unique_ptr<llvm::MemoryBuffer> main_buf; struct utsname un; uname(&un); string kdir = string(KERNEL_MODULES_DIR) + "/" + un.release; // clang needs to run inside the kernel dir DirStack dstack(kdir + "/" + KERNEL_MODULES_SUFFIX); if (!dstack.ok()) return -1; string abs_file; if (in_memory) { abs_file = main_path; main_buf = llvm::MemoryBuffer::getMemBuffer(file); } else { if (file.substr(0, 1) == "/") abs_file = file; else abs_file = string(dstack.cwd()) + "/" + file; } vector<const char *> flags_cstr({"-O0", "-emit-llvm", "-I", dstack.cwd(), "-Wno-deprecated-declarations", "-Wno-gnu-variable-sized-type-not-at-end", "-x", "c", "-c", abs_file.c_str()}); KBuildHelper kbuild_helper(kdir); vector<string> kflags; if (kbuild_helper.get_flags(un.machine, &kflags)) return -1; kflags.push_back("-include"); kflags.push_back("/virtual/include/bcc/bpf.h"); kflags.push_back("-include"); kflags.push_back("/virtual/include/bcc/helpers.h"); kflags.push_back("-isystem"); kflags.push_back("/virtual/include"); for (auto it = kflags.begin(); it != kflags.end(); ++it) flags_cstr.push_back(it->c_str()); if (cflags) { for (auto i = 0; i < ncflags; ++i) flags_cstr.push_back(cflags[i]); } // set up the error reporting class IntrusiveRefCntPtr<DiagnosticOptions> diag_opts(new DiagnosticOptions()); auto diag_client = new TextDiagnosticPrinter(llvm::errs(), &*diag_opts); IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs()); DiagnosticsEngine diags(DiagID, &*diag_opts, diag_client); // set up the command line argument wrapper #if defined(__powerpc64__) driver::Driver drv("", "ppc64le-unknown-linux-gnu", diags); #else driver::Driver drv("", "x86_64-unknown-linux-gnu", diags); #endif drv.setTitle("bcc-clang-driver"); drv.setCheckInputsExist(false); unique_ptr<driver::Compilation> compilation(drv.BuildCompilation(flags_cstr)); if (!compilation) return -1; // expect exactly 1 job, otherwise error const driver::JobList &jobs = compilation->getJobs(); if (jobs.size() != 1 || !isa<driver::Command>(*jobs.begin())) { SmallString<256> msg; llvm::raw_svector_ostream os(msg); jobs.Print(os, "; ", true); diags.Report(diag::err_fe_expected_compiler_job) << os.str(); return -1; } const driver::Command &cmd = cast<driver::Command>(*jobs.begin()); if (llvm::StringRef(cmd.getCreator().getName()) != "clang") { diags.Report(diag::err_fe_expected_clang_command); return -1; } // Initialize a compiler invocation object from the clang (-cc1) arguments. const driver::ArgStringList &ccargs = cmd.getArguments(); if (flags_ & DEBUG_PREPROCESSOR) { llvm::errs() << "clang"; for (auto arg : ccargs) llvm::errs() << " " << arg; llvm::errs() << "\n"; } // pre-compilation pass for generating tracepoint structures auto invocation0 = make_unique<CompilerInvocation>(); if (!CompilerInvocation::CreateFromArgs(*invocation0, const_cast<const char **>(ccargs.data()), const_cast<const char **>(ccargs.data()) + ccargs.size(), diags)) return -1; invocation0->getPreprocessorOpts().RetainRemappedFileBuffers = true; for (const auto &f : remapped_files_) invocation0->getPreprocessorOpts().addRemappedFile(f.first, &*f.second); if (in_memory) { invocation0->getPreprocessorOpts().addRemappedFile(main_path, &*main_buf); invocation0->getFrontendOpts().Inputs.clear(); invocation0->getFrontendOpts().Inputs.push_back(FrontendInputFile(main_path, IK_C)); } invocation0->getFrontendOpts().DisableFree = false; CompilerInstance compiler0; compiler0.setInvocation(invocation0.release()); compiler0.createDiagnostics(new IgnoringDiagConsumer()); // capture the rewritten c file string out_str; llvm::raw_string_ostream os(out_str); TracepointFrontendAction tpact(os); compiler0.ExecuteAction(tpact); // ignore errors, they will be reported later unique_ptr<llvm::MemoryBuffer> out_buf = llvm::MemoryBuffer::getMemBuffer(out_str); // first pass auto invocation1 = make_unique<CompilerInvocation>(); if (!CompilerInvocation::CreateFromArgs(*invocation1, const_cast<const char **>(ccargs.data()), const_cast<const char **>(ccargs.data()) + ccargs.size(), diags)) return -1; // This option instructs clang whether or not to free the file buffers that we // give to it. Since the embedded header files should be copied fewer times // and reused if possible, set this flag to true. invocation1->getPreprocessorOpts().RetainRemappedFileBuffers = true; for (const auto &f : remapped_files_) invocation1->getPreprocessorOpts().addRemappedFile(f.first, &*f.second); invocation1->getPreprocessorOpts().addRemappedFile(main_path, &*out_buf); invocation1->getFrontendOpts().Inputs.clear(); invocation1->getFrontendOpts().Inputs.push_back(FrontendInputFile(main_path, IK_C)); invocation1->getFrontendOpts().DisableFree = false; CompilerInstance compiler1; compiler1.setInvocation(invocation1.release()); compiler1.createDiagnostics(); // capture the rewritten c file string out_str1; llvm::raw_string_ostream os1(out_str1); BFrontendAction bact(os1, flags_); if (!compiler1.ExecuteAction(bact)) return -1; unique_ptr<llvm::MemoryBuffer> out_buf1 = llvm::MemoryBuffer::getMemBuffer(out_str1); // this contains the open FDs *tables = bact.take_tables(); // second pass, clear input and take rewrite buffer auto invocation2 = make_unique<CompilerInvocation>(); if (!CompilerInvocation::CreateFromArgs(*invocation2, const_cast<const char **>(ccargs.data()), const_cast<const char **>(ccargs.data()) + ccargs.size(), diags)) return -1; CompilerInstance compiler2; invocation2->getPreprocessorOpts().RetainRemappedFileBuffers = true; for (const auto &f : remapped_files_) invocation2->getPreprocessorOpts().addRemappedFile(f.first, &*f.second); invocation2->getPreprocessorOpts().addRemappedFile(main_path, &*out_buf1); invocation2->getFrontendOpts().Inputs.clear(); invocation2->getFrontendOpts().Inputs.push_back(FrontendInputFile(main_path, IK_C)); invocation2->getFrontendOpts().DisableFree = false; // suppress warnings in the 2nd pass, but bail out on errors (our fault) invocation2->getDiagnosticOpts().IgnoreWarnings = true; compiler2.setInvocation(invocation2.release()); compiler2.createDiagnostics(); EmitLLVMOnlyAction ir_act(&*ctx_); if (!compiler2.ExecuteAction(ir_act)) return -1; *mod = ir_act.takeModule(); return 0; } } // namespace ebpf