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