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/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 }