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-rw-r--r--tools/perf/util/c++/clang.cpp216
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diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
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+// SPDX-License-Identifier: GPL-2.0
+/*
+ * llvm C frontend for perf. Support dynamically compile C file
+ *
+ * Inspired by clang example code:
+ * http://llvm.org/svn/llvm-project/cfe/trunk/examples/clang-interpreter/main.cpp
+ *
+ * Copyright (C) 2016 Wang Nan <wangnan0@huawei.com>
+ * Copyright (C) 2016 Huawei Inc.
+ */
+
+#include "clang/Basic/Version.h"
+#include "clang/CodeGen/CodeGenAction.h"
+#include "clang/Frontend/CompilerInvocation.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/TextDiagnosticPrinter.h"
+#include "clang/Tooling/Tooling.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Option/Option.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
+#include <memory>
+
+#include "clang.h"
+#include "clang-c.h"
+
+namespace perf {
+
+static std::unique_ptr<llvm::LLVMContext> LLVMCtx;
+
+using namespace clang;
+
+static CompilerInvocation *
+createCompilerInvocation(llvm::opt::ArgStringList CFlags, StringRef& Path,
+ DiagnosticsEngine& Diags)
+{
+ llvm::opt::ArgStringList CCArgs {
+ "-cc1",
+ "-triple", "bpf-pc-linux",
+ "-fsyntax-only",
+ "-ferror-limit", "19",
+ "-fmessage-length", "127",
+ "-O2",
+ "-nostdsysteminc",
+ "-nobuiltininc",
+ "-vectorize-loops",
+ "-vectorize-slp",
+ "-Wno-unused-value",
+ "-Wno-pointer-sign",
+ "-x", "c"};
+
+ CCArgs.append(CFlags.begin(), CFlags.end());
+ CompilerInvocation *CI = tooling::newInvocation(&Diags, CCArgs);
+
+ FrontendOptions& Opts = CI->getFrontendOpts();
+ Opts.Inputs.clear();
+ Opts.Inputs.emplace_back(Path,
+ FrontendOptions::getInputKindForExtension("c"));
+ return CI;
+}
+
+static std::unique_ptr<llvm::Module>
+getModuleFromSource(llvm::opt::ArgStringList CFlags,
+ StringRef Path, IntrusiveRefCntPtr<vfs::FileSystem> VFS)
+{
+ CompilerInstance Clang;
+ Clang.createDiagnostics();
+
+#if CLANG_VERSION_MAJOR < 9
+ Clang.setVirtualFileSystem(&*VFS);
+#else
+ Clang.createFileManager(&*VFS);
+#endif
+
+#if CLANG_VERSION_MAJOR < 4
+ IntrusiveRefCntPtr<CompilerInvocation> CI =
+ createCompilerInvocation(std::move(CFlags), Path,
+ Clang.getDiagnostics());
+ Clang.setInvocation(&*CI);
+#else
+ std::shared_ptr<CompilerInvocation> CI(
+ createCompilerInvocation(std::move(CFlags), Path,
+ Clang.getDiagnostics()));
+ Clang.setInvocation(CI);
+#endif
+
+ std::unique_ptr<CodeGenAction> Act(new EmitLLVMOnlyAction(&*LLVMCtx));
+ if (!Clang.ExecuteAction(*Act))
+ return std::unique_ptr<llvm::Module>(nullptr);
+
+ return Act->takeModule();
+}
+
+std::unique_ptr<llvm::Module>
+getModuleFromSource(llvm::opt::ArgStringList CFlags,
+ StringRef Name, StringRef Content)
+{
+ using namespace vfs;
+
+ llvm::IntrusiveRefCntPtr<OverlayFileSystem> OverlayFS(
+ new OverlayFileSystem(getRealFileSystem()));
+ llvm::IntrusiveRefCntPtr<InMemoryFileSystem> MemFS(
+ new InMemoryFileSystem(true));
+
+ /*
+ * pushOverlay helps setting working dir for MemFS. Must call
+ * before addFile.
+ */
+ OverlayFS->pushOverlay(MemFS);
+ MemFS->addFile(Twine(Name), 0, llvm::MemoryBuffer::getMemBuffer(Content));
+
+ return getModuleFromSource(std::move(CFlags), Name, OverlayFS);
+}
+
+std::unique_ptr<llvm::Module>
+getModuleFromSource(llvm::opt::ArgStringList CFlags, StringRef Path)
+{
+ IntrusiveRefCntPtr<vfs::FileSystem> VFS(vfs::getRealFileSystem());
+ return getModuleFromSource(std::move(CFlags), Path, VFS);
+}
+
+std::unique_ptr<llvm::SmallVectorImpl<char>>
+getBPFObjectFromModule(llvm::Module *Module)
+{
+ using namespace llvm;
+
+ std::string TargetTriple("bpf-pc-linux");
+ std::string Error;
+ const Target* Target = TargetRegistry::lookupTarget(TargetTriple, Error);
+ if (!Target) {
+ llvm::errs() << Error;
+ return std::unique_ptr<llvm::SmallVectorImpl<char>>(nullptr);
+ }
+
+ llvm::TargetOptions Opt;
+ TargetMachine *TargetMachine =
+ Target->createTargetMachine(TargetTriple,
+ "generic", "",
+ Opt, Reloc::Static);
+
+ Module->setDataLayout(TargetMachine->createDataLayout());
+ Module->setTargetTriple(TargetTriple);
+
+ std::unique_ptr<SmallVectorImpl<char>> Buffer(new SmallVector<char, 0>());
+ raw_svector_ostream ostream(*Buffer);
+
+ legacy::PassManager PM;
+ bool NotAdded;
+#if CLANG_VERSION_MAJOR < 7
+ NotAdded = TargetMachine->addPassesToEmitFile(PM, ostream,
+ TargetMachine::CGFT_ObjectFile);
+#else
+ NotAdded = TargetMachine->addPassesToEmitFile(PM, ostream, nullptr,
+ TargetMachine::CGFT_ObjectFile);
+#endif
+ if (NotAdded) {
+ llvm::errs() << "TargetMachine can't emit a file of this type\n";
+ return std::unique_ptr<llvm::SmallVectorImpl<char>>(nullptr);
+ }
+ PM.run(*Module);
+
+ return Buffer;
+}
+
+}
+
+extern "C" {
+void perf_clang__init(void)
+{
+ perf::LLVMCtx.reset(new llvm::LLVMContext());
+ LLVMInitializeBPFTargetInfo();
+ LLVMInitializeBPFTarget();
+ LLVMInitializeBPFTargetMC();
+ LLVMInitializeBPFAsmPrinter();
+}
+
+void perf_clang__cleanup(void)
+{
+ perf::LLVMCtx.reset(nullptr);
+ llvm::llvm_shutdown();
+}
+
+int perf_clang__compile_bpf(const char *filename,
+ void **p_obj_buf,
+ size_t *p_obj_buf_sz)
+{
+ using namespace perf;
+
+ if (!p_obj_buf || !p_obj_buf_sz)
+ return -EINVAL;
+
+ llvm::opt::ArgStringList CFlags;
+ auto M = getModuleFromSource(std::move(CFlags), filename);
+ if (!M)
+ return -EINVAL;
+ auto O = getBPFObjectFromModule(&*M);
+ if (!O)
+ return -EINVAL;
+
+ size_t size = O->size_in_bytes();
+ void *buffer;
+
+ buffer = malloc(size);
+ if (!buffer)
+ return -ENOMEM;
+ memcpy(buffer, O->data(), size);
+ *p_obj_buf = buffer;
+ *p_obj_buf_sz = size;
+ return 0;
+}
+}