clang/tools/driver/cc1_main.cpp

   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/MCSubtargetInfo.h"
  32 #include "llvm/MC/TargetRegistry.h"
  33 #include "llvm/Option/Arg.h"
  34 #include "llvm/Option/ArgList.h"
  35 #include "llvm/Option/OptTable.h"
  36 #include "llvm/Support/BuryPointer.h"
  37 #include "llvm/Support/Compiler.h"
  38 #include "llvm/Support/ErrorHandling.h"
  39 #include "llvm/Support/ManagedStatic.h"
  40 #include "llvm/Support/Path.h"
  41 #include "llvm/Support/Process.h"
  42 #include "llvm/Support/RISCVISAInfo.h"
  43 #include "llvm/Support/Signals.h"
  44 #include "llvm/Support/TargetSelect.h"
  45 #include "llvm/Support/TimeProfiler.h"
  46 #include "llvm/Support/Timer.h"
  47 #include "llvm/Support/raw_ostream.h"
  48 #include "llvm/Target/TargetMachine.h"
  49 #include "llvm/TargetParser/AArch64TargetParser.h"
  50 #include "llvm/TargetParser/ARMTargetParser.h"
  51 #include <cstdio>
  52
  53 #ifdef CLANG_HAVE_RLIMITS
  54 #include <sys/resource.h>
  55 #endif
  56
  57 using namespace clang;
  58 using namespace llvm::opt;
  59
  60 //===----------------------------------------------------------------------===//
  61 // Main driver
  62 //===----------------------------------------------------------------------===//
  63
  64 static void LLVMErrorHandler(void *UserData, const char *Message,
  65                              bool GenCrashDiag) {
  66   DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
  67
  68   Diags.Report(diag::err_fe_error_backend) << Message;
  69
  70   // Run the interrupt handlers to make sure any special cleanups get done, in
  71   // particular that we remove files registered with RemoveFileOnSignal.
  72   llvm::sys::RunInterruptHandlers();
  73
  74   // We cannot recover from llvm errors.  When reporting a fatal error, exit
  75   // with status 70 to generate crash diagnostics.  For BSD systems this is
  76   // defined as an internal software error.  Otherwise, exit with status 1.
  77   llvm::sys::Process::Exit(GenCrashDiag ? 70 : 1);
  78 }
  79
  80 #ifdef CLANG_HAVE_RLIMITS
  81 #if defined(__linux__) && defined(__PIE__)
  82 static size_t getCurrentStackAllocation() {
  83   // If we can't compute the current stack usage, allow for 512K of command
  84   // line arguments and environment.
  85   size_t Usage = 512 * 1024;
  86   if (FILE *StatFile = fopen("/proc/self/stat", "r")) {
  87     // We assume that the stack extends from its current address to the end of
  88     // the environment space. In reality, there is another string literal (the
  89     // program name) after the environment, but this is close enough (we only
  90     // need to be within 100K or so).
  91     unsigned long StackPtr, EnvEnd;
  92     // Disable silly GCC -Wformat warning that complains about length
  93     // modifiers on ignored format specifiers. We want to retain these
  94     // for documentation purposes even though they have no effect.
  95 #if defined(__GNUC__) && !defined(__clang__)
  96 #pragma GCC diagnostic push
  97 #pragma GCC diagnostic ignored "-Wformat"
  98 #endif
  99     if (fscanf(StatFile,
 100                "%*d %*s %*c %*d %*d %*d %*d %*d %*u %*lu %*lu %*lu %*lu %*lu "
 101                "%*lu %*ld %*ld %*ld %*ld %*ld %*ld %*llu %*lu %*ld %*lu %*lu "
 102                "%*lu %*lu %lu %*lu %*lu %*lu %*lu %*lu %*llu %*lu %*lu %*d %*d "
 103                "%*u %*u %*llu %*lu %*ld %*lu %*lu %*lu %*lu %*lu %*lu %lu %*d",
 104                &StackPtr, &EnvEnd) == 2) {
 105 #if defined(__GNUC__) && !defined(__clang__)
 106 #pragma GCC diagnostic pop
 107 #endif
 108       Usage = StackPtr < EnvEnd ? EnvEnd - StackPtr : StackPtr - EnvEnd;
 109     }
 110     fclose(StatFile);
 111   }
 112   return Usage;
 113 }
 114
 115 #include <alloca.h>
 116
 117 LLVM_ATTRIBUTE_NOINLINE
 118 static void ensureStackAddressSpace() {
 119   // Linux kernels prior to 4.1 will sometimes locate the heap of a PIE binary
 120   // relatively close to the stack (they are only guaranteed to be 128MiB
 121   // apart). This results in crashes if we happen to heap-allocate more than
 122   // 128MiB before we reach our stack high-water mark.
 123   //
 124   // To avoid these crashes, ensure that we have sufficient virtual memory
 125   // pages allocated before we start running.
 126   size_t Curr = getCurrentStackAllocation();
 127   const int kTargetStack = DesiredStackSize - 256 * 1024;
 128   if (Curr < kTargetStack) {
 129     volatile char *volatile Alloc =
 130         static_cast<volatile char *>(alloca(kTargetStack - Curr));
 131     Alloc[0] = 0;
 132     Alloc[kTargetStack - Curr - 1] = 0;
 133   }
 134 }
 135 #else
 136 static void ensureStackAddressSpace() {}
 137 #endif
 138
 139 /// Attempt to ensure that we have at least 8MiB of usable stack space.
 140 static void ensureSufficientStack() {
 141   struct rlimit rlim;
 142   if (getrlimit(RLIMIT_STACK, &rlim) != 0)
 143     return;
 144
 145   // Increase the soft stack limit to our desired level, if necessary and
 146   // possible.
 147   if (rlim.rlim_cur != RLIM_INFINITY &&
 148       rlim.rlim_cur < rlim_t(DesiredStackSize)) {
 149     // Try to allocate sufficient stack.
 150     if (rlim.rlim_max == RLIM_INFINITY ||
 151         rlim.rlim_max >= rlim_t(DesiredStackSize))
 152       rlim.rlim_cur = DesiredStackSize;
 153     else if (rlim.rlim_cur == rlim.rlim_max)
 154       return;
 155     else
 156       rlim.rlim_cur = rlim.rlim_max;
 157
 158     if (setrlimit(RLIMIT_STACK, &rlim) != 0 ||
 159         rlim.rlim_cur != DesiredStackSize)
 160       return;
 161   }
 162
 163   // We should now have a stack of size at least DesiredStackSize. Ensure
 164   // that we can actually use that much, if necessary.
 165   ensureStackAddressSpace();
 166 }
 167 #else
 168 static void ensureSufficientStack() {}
 169 #endif
 170
 171 /// Print supported cpus of the given target.
 172 static int PrintSupportedCPUs(std::string TargetStr) {
 173   std::string Error;
 174   const llvm::Target *TheTarget =
 175       llvm::TargetRegistry::lookupTarget(TargetStr, Error);
 176   if (!TheTarget) {
 177     llvm::errs() << Error;
 178     return 1;
 179   }
 180
 181   // the target machine will handle the mcpu printing
 182   llvm::TargetOptions Options;
 183   std::unique_ptr<llvm::TargetMachine> TheTargetMachine(
 184       TheTarget->createTargetMachine(TargetStr, "", "+cpuhelp", Options,
 185                                      std::nullopt));
 186   return 0;
 187 }
 188
 189 static int PrintSupportedExtensions(std::string TargetStr) {
 190   std::string Error;
 191   const llvm::Target *TheTarget =
 192       llvm::TargetRegistry::lookupTarget(TargetStr, Error);
 193   if (!TheTarget) {
 194     llvm::errs() << Error;
 195     return 1;
 196   }
 197
 198   llvm::TargetOptions Options;
 199   std::unique_ptr<llvm::TargetMachine> TheTargetMachine(
 200       TheTarget->createTargetMachine(TargetStr, "", "", Options, std::nullopt));
 201   const llvm::Triple &MachineTriple = TheTargetMachine->getTargetTriple();
 202   const llvm::MCSubtargetInfo *MCInfo = TheTargetMachine->getMCSubtargetInfo();
 203   const llvm::ArrayRef<llvm::SubtargetFeatureKV> Features =
 204     MCInfo->getAllProcessorFeatures();
 205
 206   llvm::StringMap<llvm::StringRef> DescMap;
 207   for (const llvm::SubtargetFeatureKV &feature : Features)
 208     DescMap.insert({feature.Key, feature.Desc});
 209
 210   if (MachineTriple.isRISCV())
 211     llvm::riscvExtensionsHelp(DescMap);
 212   else if (MachineTriple.isAArch64())
 213     llvm::AArch64::PrintSupportedExtensions(DescMap);
 214   else if (MachineTriple.isARM())
 215     llvm::ARM::PrintSupportedExtensions(DescMap);
 216   else {
 217     // The option was already checked in Driver::HandleImmediateArgs,
 218     // so we do not expect to get here if we are not a supported architecture.
 219     assert(0 && "Unhandled triple for --print-supported-extensions option.");
 220     return 1;
 221   }
 222
 223   return 0;
 224 }
 225
 226 int cc1_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) {
 227   ensureSufficientStack();
 228
 229   std::unique_ptr<CompilerInstance> Clang(new CompilerInstance());
 230   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
 231
 232   // Register the support for object-file-wrapped Clang modules.
 233   auto PCHOps = Clang->getPCHContainerOperations();
 234   PCHOps->registerWriter(std::make_unique<ObjectFilePCHContainerWriter>());
 235   PCHOps->registerReader(std::make_unique<ObjectFilePCHContainerReader>());
 236
 237   // Initialize targets first, so that --version shows registered targets.
 238   llvm::InitializeAllTargets();
 239   llvm::InitializeAllTargetMCs();
 240   llvm::InitializeAllAsmPrinters();
 241   llvm::InitializeAllAsmParsers();
 242
 243   // Buffer diagnostics from argument parsing so that we can output them using a
 244   // well formed diagnostic object.
 245   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
 246   TextDiagnosticBuffer *DiagsBuffer = new TextDiagnosticBuffer;
 247   DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagsBuffer);
 248
 249   // Setup round-trip remarks for the DiagnosticsEngine used in CreateFromArgs.
 250   if (find(Argv, StringRef("-Rround-trip-cc1-args")) != Argv.end())
 251     Diags.setSeverity(diag::remark_cc1_round_trip_generated,
 252                       diag::Severity::Remark, {});
 253
 254   bool Success = CompilerInvocation::CreateFromArgs(Clang->getInvocation(),
 255                                                     Argv, Diags, Argv0);
 256
 257   if (!Clang->getFrontendOpts().TimeTracePath.empty()) {
 258     llvm::timeTraceProfilerInitialize(
 259         Clang->getFrontendOpts().TimeTraceGranularity, Argv0);
 260   }
 261   // --print-supported-cpus takes priority over the actual compilation.
 262   if (Clang->getFrontendOpts().PrintSupportedCPUs)
 263     return PrintSupportedCPUs(Clang->getTargetOpts().Triple);
 264
 265   // --print-supported-extensions takes priority over the actual compilation.
 266   if (Clang->getFrontendOpts().PrintSupportedExtensions)
 267     return PrintSupportedExtensions(Clang->getTargetOpts().Triple);
 268
 269   // Infer the builtin include path if unspecified.
 270   if (Clang->getHeaderSearchOpts().UseBuiltinIncludes &&
 271       Clang->getHeaderSearchOpts().ResourceDir.empty())
 272     Clang->getHeaderSearchOpts().ResourceDir =
 273       CompilerInvocation::GetResourcesPath(Argv0, MainAddr);
 274
 275   // Create the actual diagnostics engine.
 276   Clang->createDiagnostics();
 277   if (!Clang->hasDiagnostics())
 278     return 1;
 279
 280   // Set an error handler, so that any LLVM backend diagnostics go through our
 281   // error handler.
 282   llvm::install_fatal_error_handler(LLVMErrorHandler,
 283                                   static_cast<void*>(&Clang->getDiagnostics()));
 284
 285   DiagsBuffer->FlushDiagnostics(Clang->getDiagnostics());
 286   if (!Success) {
 287     Clang->getDiagnosticClient().finish();
 288     return 1;
 289   }
 290
 291   // Execute the frontend actions.
 292   {
 293     llvm::TimeTraceScope TimeScope("ExecuteCompiler");
 294     Success = ExecuteCompilerInvocation(Clang.get());
 295   }
 296
 297   // If any timers were active but haven't been destroyed yet, print their
 298   // results now.  This happens in -disable-free mode.
 299   llvm::TimerGroup::printAll(llvm::errs());
 300   llvm::TimerGroup::clearAll();
 301
 302   if (llvm::timeTraceProfilerEnabled()) {
 303     // It is possible that the compiler instance doesn't own a file manager here
 304     // if we're compiling a module unit. Since the file manager are owned by AST
 305     // when we're compiling a module unit. So the file manager may be invalid
 306     // here.
 307     //
 308     // It should be fine to create file manager here since the file system
 309     // options are stored in the compiler invocation and we can recreate the VFS
 310     // from the compiler invocation.
 311     if (!Clang->hasFileManager())
 312       Clang->createFileManager(createVFSFromCompilerInvocation(
 313           Clang->getInvocation(), Clang->getDiagnostics()));
 314
 315     if (auto profilerOutput = Clang->createOutputFile(
 316             Clang->getFrontendOpts().TimeTracePath, /*Binary=*/false,
 317             /*RemoveFileOnSignal=*/false,
 318             /*useTemporary=*/false)) {
 319       llvm::timeTraceProfilerWrite(*profilerOutput);
 320       profilerOutput.reset();
 321       llvm::timeTraceProfilerCleanup();
 322       Clang->clearOutputFiles(false);
 323     }
 324   }
 325
 326   // Our error handler depends on the Diagnostics object, which we're
 327   // potentially about to delete. Uninstall the handler now so that any
 328   // later errors use the default handling behavior instead.
 329   llvm::remove_fatal_error_handler();
 330
 331   // When running with -disable-free, don't do any destruction or shutdown.
 332   if (Clang->getFrontendOpts().DisableFree) {
 333     llvm::BuryPointer(std::move(Clang));
 334     return !Success;
 335   }
 336
 337   return !Success;
 338 }