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/Option/Arg.h" 32 #include "llvm/Option/ArgList.h" 33 #include "llvm/Option/OptTable.h" 34 #include "llvm/Support/BuryPointer.h" 35 #include "llvm/Support/Compiler.h" 36 #include "llvm/Support/ErrorHandling.h" 37 #include "llvm/Support/ManagedStatic.h" 38 #include "llvm/Support/Path.h" 39 #include "llvm/Support/Signals.h" 40 #include "llvm/Support/TargetRegistry.h" 41 #include "llvm/Support/TargetSelect.h" 42 #include "llvm/Support/TimeProfiler.h" 43 #include "llvm/Support/Timer.h" 44 #include "llvm/Support/raw_ostream.h" 45 #include "llvm/Target/TargetMachine.h" 46 #include <cstdio> 47 48 #ifdef CLANG_HAVE_RLIMITS 49 #include <sys/resource.h> 50 #endif 51 52 using namespace clang; 53 using namespace llvm::opt; 54 55 //===----------------------------------------------------------------------===// 56 // Main driver 57 //===----------------------------------------------------------------------===// 58 59 static void LLVMErrorHandler(void *UserData, const std::string &Message, 60 bool GenCrashDiag) { 61 DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData); 62 63 Diags.Report(diag::err_fe_error_backend) << Message; 64 65 // Run the interrupt handlers to make sure any special cleanups get done, in 66 // particular that we remove files registered with RemoveFileOnSignal. 67 llvm::sys::RunInterruptHandlers(); 68 69 // We cannot recover from llvm errors. When reporting a fatal error, exit 70 // with status 70 to generate crash diagnostics. For BSD systems this is 71 // defined as an internal software error. Otherwise, exit with status 1. 72 exit(GenCrashDiag ? 70 : 1); 73 } 74 75 #ifdef LINK_POLLY_INTO_TOOLS 76 namespace polly { 77 void initializePollyPasses(llvm::PassRegistry &Registry); 78 } 79 #endif 80 81 #ifdef CLANG_HAVE_RLIMITS 82 #if defined(__linux__) && defined(__PIE__) 83 static size_t getCurrentStackAllocation() { 84 // If we can't compute the current stack usage, allow for 512K of command 85 // line arguments and environment. 86 size_t Usage = 512 * 1024; 87 if (FILE *StatFile = fopen("/proc/self/stat", "r")) { 88 // We assume that the stack extends from its current address to the end of 89 // the environment space. In reality, there is another string literal (the 90 // program name) after the environment, but this is close enough (we only 91 // need to be within 100K or so). 92 unsigned long StackPtr, EnvEnd; 93 // Disable silly GCC -Wformat warning that complains about length 94 // modifiers on ignored format specifiers. We want to retain these 95 // for documentation purposes even though they have no effect. 96 #if defined(__GNUC__) && !defined(__clang__) 97 #pragma GCC diagnostic push 98 #pragma GCC diagnostic ignored "-Wformat" 99 #endif 100 if (fscanf(StatFile, 101 "%*d %*s %*c %*d %*d %*d %*d %*d %*u %*lu %*lu %*lu %*lu %*lu " 102 "%*lu %*ld %*ld %*ld %*ld %*ld %*ld %*llu %*lu %*ld %*lu %*lu " 103 "%*lu %*lu %lu %*lu %*lu %*lu %*lu %*lu %*llu %*lu %*lu %*d %*d " 104 "%*u %*u %*llu %*lu %*ld %*lu %*lu %*lu %*lu %*lu %*lu %lu %*d", 105 &StackPtr, &EnvEnd) == 2) { 106 #if defined(__GNUC__) && !defined(__clang__) 107 #pragma GCC diagnostic pop 108 #endif 109 Usage = StackPtr < EnvEnd ? EnvEnd - StackPtr : StackPtr - EnvEnd; 110 } 111 fclose(StatFile); 112 } 113 return Usage; 114 } 115 116 #include <alloca.h> 117 118 LLVM_ATTRIBUTE_NOINLINE 119 static void ensureStackAddressSpace() { 120 // Linux kernels prior to 4.1 will sometimes locate the heap of a PIE binary 121 // relatively close to the stack (they are only guaranteed to be 128MiB 122 // apart). This results in crashes if we happen to heap-allocate more than 123 // 128MiB before we reach our stack high-water mark. 124 // 125 // To avoid these crashes, ensure that we have sufficient virtual memory 126 // pages allocated before we start running. 127 size_t Curr = getCurrentStackAllocation(); 128 const int kTargetStack = DesiredStackSize - 256 * 1024; 129 if (Curr < kTargetStack) { 130 volatile char *volatile Alloc = 131 static_cast<volatile char *>(alloca(kTargetStack - Curr)); 132 Alloc[0] = 0; 133 Alloc[kTargetStack - Curr - 1] = 0; 134 } 135 } 136 #else 137 static void ensureStackAddressSpace() {} 138 #endif 139 140 /// Attempt to ensure that we have at least 8MiB of usable stack space. 141 static void ensureSufficientStack() { 142 struct rlimit rlim; 143 if (getrlimit(RLIMIT_STACK, &rlim) != 0) 144 return; 145 146 // Increase the soft stack limit to our desired level, if necessary and 147 // possible. 148 if (rlim.rlim_cur != RLIM_INFINITY && 149 rlim.rlim_cur < rlim_t(DesiredStackSize)) { 150 // Try to allocate sufficient stack. 151 if (rlim.rlim_max == RLIM_INFINITY || 152 rlim.rlim_max >= rlim_t(DesiredStackSize)) 153 rlim.rlim_cur = DesiredStackSize; 154 else if (rlim.rlim_cur == rlim.rlim_max) 155 return; 156 else 157 rlim.rlim_cur = rlim.rlim_max; 158 159 if (setrlimit(RLIMIT_STACK, &rlim) != 0 || 160 rlim.rlim_cur != DesiredStackSize) 161 return; 162 } 163 164 // We should now have a stack of size at least DesiredStackSize. Ensure 165 // that we can actually use that much, if necessary. 166 ensureStackAddressSpace(); 167 } 168 #else 169 static void ensureSufficientStack() {} 170 #endif 171 172 /// Print supported cpus of the given target. 173 static int PrintSupportedCPUs(std::string TargetStr) { 174 std::string Error; 175 const llvm::Target *TheTarget = 176 llvm::TargetRegistry::lookupTarget(TargetStr, Error); 177 if (!TheTarget) { 178 llvm::errs() << Error; 179 return 1; 180 } 181 182 // the target machine will handle the mcpu printing 183 llvm::TargetOptions Options; 184 std::unique_ptr<llvm::TargetMachine> TheTargetMachine( 185 TheTarget->createTargetMachine(TargetStr, "", "+cpuHelp", Options, None)); 186 return 0; 187 } 188 189 int cc1_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) { 190 ensureSufficientStack(); 191 192 std::unique_ptr<CompilerInstance> Clang(new CompilerInstance()); 193 IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs()); 194 195 // Register the support for object-file-wrapped Clang modules. 196 auto PCHOps = Clang->getPCHContainerOperations(); 197 PCHOps->registerWriter(std::make_unique<ObjectFilePCHContainerWriter>()); 198 PCHOps->registerReader(std::make_unique<ObjectFilePCHContainerReader>()); 199 200 // Initialize targets first, so that --version shows registered targets. 201 llvm::InitializeAllTargets(); 202 llvm::InitializeAllTargetMCs(); 203 llvm::InitializeAllAsmPrinters(); 204 llvm::InitializeAllAsmParsers(); 205 206 #ifdef LINK_POLLY_INTO_TOOLS 207 llvm::PassRegistry &Registry = *llvm::PassRegistry::getPassRegistry(); 208 polly::initializePollyPasses(Registry); 209 #endif 210 211 // Buffer diagnostics from argument parsing so that we can output them using a 212 // well formed diagnostic object. 213 IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions(); 214 TextDiagnosticBuffer *DiagsBuffer = new TextDiagnosticBuffer; 215 DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagsBuffer); 216 bool Success = 217 CompilerInvocation::CreateFromArgs(Clang->getInvocation(), Argv, Diags); 218 219 if (Clang->getFrontendOpts().TimeTrace) { 220 llvm::timeTraceProfilerInitialize( 221 Clang->getFrontendOpts().TimeTraceGranularity); 222 } 223 // --print-supported-cpus takes priority over the actual compilation. 224 if (Clang->getFrontendOpts().PrintSupportedCPUs) 225 return PrintSupportedCPUs(Clang->getTargetOpts().Triple); 226 227 // Infer the builtin include path if unspecified. 228 if (Clang->getHeaderSearchOpts().UseBuiltinIncludes && 229 Clang->getHeaderSearchOpts().ResourceDir.empty()) 230 Clang->getHeaderSearchOpts().ResourceDir = 231 CompilerInvocation::GetResourcesPath(Argv0, MainAddr); 232 233 // Create the actual diagnostics engine. 234 Clang->createDiagnostics(); 235 if (!Clang->hasDiagnostics()) 236 return 1; 237 238 // Set an error handler, so that any LLVM backend diagnostics go through our 239 // error handler. 240 llvm::install_fatal_error_handler(LLVMErrorHandler, 241 static_cast<void*>(&Clang->getDiagnostics())); 242 243 DiagsBuffer->FlushDiagnostics(Clang->getDiagnostics()); 244 if (!Success) 245 return 1; 246 247 // Execute the frontend actions. 248 { 249 llvm::TimeTraceScope TimeScope("ExecuteCompiler", StringRef("")); 250 Success = ExecuteCompilerInvocation(Clang.get()); 251 } 252 253 // If any timers were active but haven't been destroyed yet, print their 254 // results now. This happens in -disable-free mode. 255 llvm::TimerGroup::printAll(llvm::errs()); 256 llvm::TimerGroup::clearAll(); 257 258 if (llvm::timeTraceProfilerEnabled()) { 259 SmallString<128> Path(Clang->getFrontendOpts().OutputFile); 260 llvm::sys::path::replace_extension(Path, "json"); 261 if (auto profilerOutput = 262 Clang->createOutputFile(Path.str(), 263 /*Binary=*/false, 264 /*RemoveFileOnSignal=*/false, "", 265 /*Extension=*/"json", 266 /*useTemporary=*/false)) { 267 268 llvm::timeTraceProfilerWrite(*profilerOutput); 269 // FIXME(ibiryukov): make profilerOutput flush in destructor instead. 270 profilerOutput->flush(); 271 llvm::timeTraceProfilerCleanup(); 272 } 273 } 274 275 // Our error handler depends on the Diagnostics object, which we're 276 // potentially about to delete. Uninstall the handler now so that any 277 // later errors use the default handling behavior instead. 278 llvm::remove_fatal_error_handler(); 279 280 // When running with -disable-free, don't do any destruction or shutdown. 281 if (Clang->getFrontendOpts().DisableFree) { 282 llvm::BuryPointer(std::move(Clang)); 283 return !Success; 284 } 285 286 return !Success; 287 } 288