1 //===-- cc1_main.cpp - Clang CC1 Compiler Frontend ------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This is the entry point to the clang -cc1 functionality, which implements the 10 // core compiler functionality along with a number of additional tools for 11 // demonstration and testing purposes. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "clang/Basic/Stack.h" 16 #include "clang/Basic/TargetOptions.h" 17 #include "clang/CodeGen/ObjectFilePCHContainerOperations.h" 18 #include "clang/Config/config.h" 19 #include "clang/Driver/DriverDiagnostic.h" 20 #include "clang/Driver/Options.h" 21 #include "clang/Frontend/CompilerInstance.h" 22 #include "clang/Frontend/CompilerInvocation.h" 23 #include "clang/Frontend/FrontendDiagnostic.h" 24 #include "clang/Frontend/TextDiagnosticBuffer.h" 25 #include "clang/Frontend/TextDiagnosticPrinter.h" 26 #include "clang/Frontend/Utils.h" 27 #include "clang/FrontendTool/Utils.h" 28 #include "llvm/ADT/Statistic.h" 29 #include "llvm/Config/llvm-config.h" 30 #include "llvm/LinkAllPasses.h" 31 #include "llvm/MC/TargetRegistry.h" 32 #include "llvm/Option/Arg.h" 33 #include "llvm/Option/ArgList.h" 34 #include "llvm/Option/OptTable.h" 35 #include "llvm/Support/BuryPointer.h" 36 #include "llvm/Support/Compiler.h" 37 #include "llvm/Support/ErrorHandling.h" 38 #include "llvm/Support/ManagedStatic.h" 39 #include "llvm/Support/Path.h" 40 #include "llvm/Support/Process.h" 41 #include "llvm/Support/Signals.h" 42 #include "llvm/Support/TargetSelect.h" 43 #include "llvm/Support/TimeProfiler.h" 44 #include "llvm/Support/Timer.h" 45 #include "llvm/Support/raw_ostream.h" 46 #include "llvm/Target/TargetMachine.h" 47 #include <cstdio> 48 49 #ifdef CLANG_HAVE_RLIMITS 50 #include <sys/resource.h> 51 #endif 52 53 using namespace clang; 54 using namespace llvm::opt; 55 56 //===----------------------------------------------------------------------===// 57 // Main driver 58 //===----------------------------------------------------------------------===// 59 60 static void LLVMErrorHandler(void *UserData, const char *Message, 61 bool GenCrashDiag) { 62 DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData); 63 64 Diags.Report(diag::err_fe_error_backend) << Message; 65 66 // Run the interrupt handlers to make sure any special cleanups get done, in 67 // particular that we remove files registered with RemoveFileOnSignal. 68 llvm::sys::RunInterruptHandlers(); 69 70 // We cannot recover from llvm errors. When reporting a fatal error, exit 71 // with status 70 to generate crash diagnostics. For BSD systems this is 72 // defined as an internal software error. Otherwise, exit with status 1. 73 llvm::sys::Process::Exit(GenCrashDiag ? 70 : 1); 74 } 75 76 #ifdef CLANG_HAVE_RLIMITS 77 #if defined(__linux__) && defined(__PIE__) 78 static size_t getCurrentStackAllocation() { 79 // If we can't compute the current stack usage, allow for 512K of command 80 // line arguments and environment. 81 size_t Usage = 512 * 1024; 82 if (FILE *StatFile = fopen("/proc/self/stat", "r")) { 83 // We assume that the stack extends from its current address to the end of 84 // the environment space. In reality, there is another string literal (the 85 // program name) after the environment, but this is close enough (we only 86 // need to be within 100K or so). 87 unsigned long StackPtr, EnvEnd; 88 // Disable silly GCC -Wformat warning that complains about length 89 // modifiers on ignored format specifiers. We want to retain these 90 // for documentation purposes even though they have no effect. 91 #if defined(__GNUC__) && !defined(__clang__) 92 #pragma GCC diagnostic push 93 #pragma GCC diagnostic ignored "-Wformat" 94 #endif 95 if (fscanf(StatFile, 96 "%*d %*s %*c %*d %*d %*d %*d %*d %*u %*lu %*lu %*lu %*lu %*lu " 97 "%*lu %*ld %*ld %*ld %*ld %*ld %*ld %*llu %*lu %*ld %*lu %*lu " 98 "%*lu %*lu %lu %*lu %*lu %*lu %*lu %*lu %*llu %*lu %*lu %*d %*d " 99 "%*u %*u %*llu %*lu %*ld %*lu %*lu %*lu %*lu %*lu %*lu %lu %*d", 100 &StackPtr, &EnvEnd) == 2) { 101 #if defined(__GNUC__) && !defined(__clang__) 102 #pragma GCC diagnostic pop 103 #endif 104 Usage = StackPtr < EnvEnd ? EnvEnd - StackPtr : StackPtr - EnvEnd; 105 } 106 fclose(StatFile); 107 } 108 return Usage; 109 } 110 111 #include <alloca.h> 112 113 LLVM_ATTRIBUTE_NOINLINE 114 static void ensureStackAddressSpace() { 115 // Linux kernels prior to 4.1 will sometimes locate the heap of a PIE binary 116 // relatively close to the stack (they are only guaranteed to be 128MiB 117 // apart). This results in crashes if we happen to heap-allocate more than 118 // 128MiB before we reach our stack high-water mark. 119 // 120 // To avoid these crashes, ensure that we have sufficient virtual memory 121 // pages allocated before we start running. 122 size_t Curr = getCurrentStackAllocation(); 123 const int kTargetStack = DesiredStackSize - 256 * 1024; 124 if (Curr < kTargetStack) { 125 volatile char *volatile Alloc = 126 static_cast<volatile char *>(alloca(kTargetStack - Curr)); 127 Alloc[0] = 0; 128 Alloc[kTargetStack - Curr - 1] = 0; 129 } 130 } 131 #else 132 static void ensureStackAddressSpace() {} 133 #endif 134 135 /// Attempt to ensure that we have at least 8MiB of usable stack space. 136 static void ensureSufficientStack() { 137 struct rlimit rlim; 138 if (getrlimit(RLIMIT_STACK, &rlim) != 0) 139 return; 140 141 // Increase the soft stack limit to our desired level, if necessary and 142 // possible. 143 if (rlim.rlim_cur != RLIM_INFINITY && 144 rlim.rlim_cur < rlim_t(DesiredStackSize)) { 145 // Try to allocate sufficient stack. 146 if (rlim.rlim_max == RLIM_INFINITY || 147 rlim.rlim_max >= rlim_t(DesiredStackSize)) 148 rlim.rlim_cur = DesiredStackSize; 149 else if (rlim.rlim_cur == rlim.rlim_max) 150 return; 151 else 152 rlim.rlim_cur = rlim.rlim_max; 153 154 if (setrlimit(RLIMIT_STACK, &rlim) != 0 || 155 rlim.rlim_cur != DesiredStackSize) 156 return; 157 } 158 159 // We should now have a stack of size at least DesiredStackSize. Ensure 160 // that we can actually use that much, if necessary. 161 ensureStackAddressSpace(); 162 } 163 #else 164 static void ensureSufficientStack() {} 165 #endif 166 167 /// Print supported cpus of the given target. 168 static int PrintSupportedCPUs(std::string TargetStr) { 169 std::string Error; 170 const llvm::Target *TheTarget = 171 llvm::TargetRegistry::lookupTarget(TargetStr, Error); 172 if (!TheTarget) { 173 llvm::errs() << Error; 174 return 1; 175 } 176 177 // the target machine will handle the mcpu printing 178 llvm::TargetOptions Options; 179 std::unique_ptr<llvm::TargetMachine> TheTargetMachine( 180 TheTarget->createTargetMachine(TargetStr, "", "+cpuhelp", Options, 181 std::nullopt)); 182 return 0; 183 } 184 185 int cc1_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) { 186 ensureSufficientStack(); 187 188 std::unique_ptr<CompilerInstance> Clang(new CompilerInstance()); 189 IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs()); 190 191 // Register the support for object-file-wrapped Clang modules. 192 auto PCHOps = Clang->getPCHContainerOperations(); 193 PCHOps->registerWriter(std::make_unique<ObjectFilePCHContainerWriter>()); 194 PCHOps->registerReader(std::make_unique<ObjectFilePCHContainerReader>()); 195 196 // Initialize targets first, so that --version shows registered targets. 197 llvm::InitializeAllTargets(); 198 llvm::InitializeAllTargetMCs(); 199 llvm::InitializeAllAsmPrinters(); 200 llvm::InitializeAllAsmParsers(); 201 202 // Buffer diagnostics from argument parsing so that we can output them using a 203 // well formed diagnostic object. 204 IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions(); 205 TextDiagnosticBuffer *DiagsBuffer = new TextDiagnosticBuffer; 206 DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagsBuffer); 207 208 // Setup round-trip remarks for the DiagnosticsEngine used in CreateFromArgs. 209 if (find(Argv, StringRef("-Rround-trip-cc1-args")) != Argv.end()) 210 Diags.setSeverity(diag::remark_cc1_round_trip_generated, 211 diag::Severity::Remark, {}); 212 213 bool Success = CompilerInvocation::CreateFromArgs(Clang->getInvocation(), 214 Argv, Diags, Argv0); 215 216 if (!Clang->getFrontendOpts().TimeTracePath.empty()) { 217 llvm::timeTraceProfilerInitialize( 218 Clang->getFrontendOpts().TimeTraceGranularity, Argv0); 219 } 220 // --print-supported-cpus takes priority over the actual compilation. 221 if (Clang->getFrontendOpts().PrintSupportedCPUs) 222 return PrintSupportedCPUs(Clang->getTargetOpts().Triple); 223 224 // Infer the builtin include path if unspecified. 225 if (Clang->getHeaderSearchOpts().UseBuiltinIncludes && 226 Clang->getHeaderSearchOpts().ResourceDir.empty()) 227 Clang->getHeaderSearchOpts().ResourceDir = 228 CompilerInvocation::GetResourcesPath(Argv0, MainAddr); 229 230 // Create the actual diagnostics engine. 231 Clang->createDiagnostics(); 232 if (!Clang->hasDiagnostics()) 233 return 1; 234 235 // Set an error handler, so that any LLVM backend diagnostics go through our 236 // error handler. 237 llvm::install_fatal_error_handler(LLVMErrorHandler, 238 static_cast<void*>(&Clang->getDiagnostics())); 239 240 DiagsBuffer->FlushDiagnostics(Clang->getDiagnostics()); 241 if (!Success) { 242 Clang->getDiagnosticClient().finish(); 243 return 1; 244 } 245 246 // Execute the frontend actions. 247 { 248 llvm::TimeTraceScope TimeScope("ExecuteCompiler"); 249 Success = ExecuteCompilerInvocation(Clang.get()); 250 } 251 252 // If any timers were active but haven't been destroyed yet, print their 253 // results now. This happens in -disable-free mode. 254 llvm::TimerGroup::printAll(llvm::errs()); 255 llvm::TimerGroup::clearAll(); 256 257 if (llvm::timeTraceProfilerEnabled()) { 258 // It is possible that the compiler instance doesn't own a file manager here 259 // if we're compiling a module unit. Since the file manager are owned by AST 260 // when we're compiling a module unit. So the file manager may be invalid 261 // here. 262 // 263 // It should be fine to create file manager here since the file system 264 // options are stored in the compiler invocation and we can recreate the VFS 265 // from the compiler invocation. 266 if (!Clang->hasFileManager()) 267 Clang->createFileManager(createVFSFromCompilerInvocation( 268 Clang->getInvocation(), Clang->getDiagnostics())); 269 270 if (auto profilerOutput = Clang->createOutputFile( 271 Clang->getFrontendOpts().TimeTracePath, /*Binary=*/false, 272 /*RemoveFileOnSignal=*/false, 273 /*useTemporary=*/false)) { 274 llvm::timeTraceProfilerWrite(*profilerOutput); 275 profilerOutput.reset(); 276 llvm::timeTraceProfilerCleanup(); 277 Clang->clearOutputFiles(false); 278 } 279 } 280 281 // Our error handler depends on the Diagnostics object, which we're 282 // potentially about to delete. Uninstall the handler now so that any 283 // later errors use the default handling behavior instead. 284 llvm::remove_fatal_error_handler(); 285 286 // When running with -disable-free, don't do any destruction or shutdown. 287 if (Clang->getFrontendOpts().DisableFree) { 288 llvm::BuryPointer(std::move(Clang)); 289 return !Success; 290 } 291 292 return !Success; 293 } 294