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      1 //===- lib/Support/ErrorHandling.cpp - Callbacks for errors ---------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file defines an API used to indicate fatal error conditions.  Non-fatal
     11 // errors (most of them) should be handled through LLVMContext.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "llvm/Support/ErrorHandling.h"
     16 #include "llvm-c/Core.h"
     17 #include "llvm/ADT/SmallVector.h"
     18 #include "llvm/ADT/Twine.h"
     19 #include "llvm/Config/config.h"
     20 #include "llvm/Support/Debug.h"
     21 #include "llvm/Support/Errc.h"
     22 #include "llvm/Support/ManagedStatic.h"
     23 #include "llvm/Support/Mutex.h"
     24 #include "llvm/Support/MutexGuard.h"
     25 #include "llvm/Support/Signals.h"
     26 #include "llvm/Support/Threading.h"
     27 #include "llvm/Support/WindowsError.h"
     28 #include "llvm/Support/raw_ostream.h"
     29 #include <cassert>
     30 #include <cstdlib>
     31 
     32 #if defined(HAVE_UNISTD_H)
     33 # include <unistd.h>
     34 #endif
     35 #if defined(_MSC_VER)
     36 # include <io.h>
     37 # include <fcntl.h>
     38 #endif
     39 
     40 using namespace llvm;
     41 
     42 static fatal_error_handler_t ErrorHandler = nullptr;
     43 static void *ErrorHandlerUserData = nullptr;
     44 
     45 static ManagedStatic<sys::Mutex> ErrorHandlerMutex;
     46 
     47 void llvm::install_fatal_error_handler(fatal_error_handler_t handler,
     48                                        void *user_data) {
     49   llvm::MutexGuard Lock(*ErrorHandlerMutex);
     50   assert(!ErrorHandler && "Error handler already registered!\n");
     51   ErrorHandler = handler;
     52   ErrorHandlerUserData = user_data;
     53 }
     54 
     55 void llvm::remove_fatal_error_handler() {
     56   llvm::MutexGuard Lock(*ErrorHandlerMutex);
     57   ErrorHandler = nullptr;
     58   ErrorHandlerUserData = nullptr;
     59 }
     60 
     61 void llvm::report_fatal_error(const char *Reason, bool GenCrashDiag) {
     62   report_fatal_error(Twine(Reason), GenCrashDiag);
     63 }
     64 
     65 void llvm::report_fatal_error(const std::string &Reason, bool GenCrashDiag) {
     66   report_fatal_error(Twine(Reason), GenCrashDiag);
     67 }
     68 
     69 void llvm::report_fatal_error(StringRef Reason, bool GenCrashDiag) {
     70   report_fatal_error(Twine(Reason), GenCrashDiag);
     71 }
     72 
     73 void llvm::report_fatal_error(const Twine &Reason, bool GenCrashDiag) {
     74   llvm::fatal_error_handler_t handler = nullptr;
     75   void* handlerData = nullptr;
     76   {
     77     // Only acquire the mutex while reading the handler, so as not to invoke a
     78     // user-supplied callback under a lock.
     79     llvm::MutexGuard Lock(*ErrorHandlerMutex);
     80     handler = ErrorHandler;
     81     handlerData = ErrorHandlerUserData;
     82   }
     83 
     84   if (handler) {
     85     handler(handlerData, Reason.str(), GenCrashDiag);
     86   } else {
     87     // Blast the result out to stderr.  We don't try hard to make sure this
     88     // succeeds (e.g. handling EINTR) and we can't use errs() here because
     89     // raw ostreams can call report_fatal_error.
     90     SmallVector<char, 64> Buffer;
     91     raw_svector_ostream OS(Buffer);
     92     OS << "LLVM ERROR: " << Reason << "\n";
     93     StringRef MessageStr = OS.str();
     94     ssize_t written = ::write(2, MessageStr.data(), MessageStr.size());
     95     (void)written; // If something went wrong, we deliberately just give up.
     96   }
     97 
     98   // If we reached here, we are failing ungracefully. Run the interrupt handlers
     99   // to make sure any special cleanups get done, in particular that we remove
    100   // files registered with RemoveFileOnSignal.
    101   sys::RunInterruptHandlers();
    102 
    103   exit(1);
    104 }
    105 
    106 void llvm::llvm_unreachable_internal(const char *msg, const char *file,
    107                                      unsigned line) {
    108   // This code intentionally doesn't call the ErrorHandler callback, because
    109   // llvm_unreachable is intended to be used to indicate "impossible"
    110   // situations, and not legitimate runtime errors.
    111   if (msg)
    112     dbgs() << msg << "\n";
    113   dbgs() << "UNREACHABLE executed";
    114   if (file)
    115     dbgs() << " at " << file << ":" << line;
    116   dbgs() << "!\n";
    117   abort();
    118 #ifdef LLVM_BUILTIN_UNREACHABLE
    119   // Windows systems and possibly others don't declare abort() to be noreturn,
    120   // so use the unreachable builtin to avoid a Clang self-host warning.
    121   LLVM_BUILTIN_UNREACHABLE;
    122 #endif
    123 }
    124 
    125 static void bindingsErrorHandler(void *user_data, const std::string& reason,
    126                                  bool gen_crash_diag) {
    127   LLVMFatalErrorHandler handler =
    128       LLVM_EXTENSION reinterpret_cast<LLVMFatalErrorHandler>(user_data);
    129   handler(reason.c_str());
    130 }
    131 
    132 void LLVMInstallFatalErrorHandler(LLVMFatalErrorHandler Handler) {
    133   install_fatal_error_handler(bindingsErrorHandler,
    134                               LLVM_EXTENSION reinterpret_cast<void *>(Handler));
    135 }
    136 
    137 void LLVMResetFatalErrorHandler() {
    138   remove_fatal_error_handler();
    139 }
    140 
    141 #ifdef LLVM_ON_WIN32
    142 
    143 #include <winerror.h>
    144 
    145 // I'd rather not double the line count of the following.
    146 #define MAP_ERR_TO_COND(x, y)                                                  \
    147   case x:                                                                      \
    148     return make_error_code(errc::y)
    149 
    150 std::error_code llvm::mapWindowsError(unsigned EV) {
    151   switch (EV) {
    152     MAP_ERR_TO_COND(ERROR_ACCESS_DENIED, permission_denied);
    153     MAP_ERR_TO_COND(ERROR_ALREADY_EXISTS, file_exists);
    154     MAP_ERR_TO_COND(ERROR_BAD_UNIT, no_such_device);
    155     MAP_ERR_TO_COND(ERROR_BUFFER_OVERFLOW, filename_too_long);
    156     MAP_ERR_TO_COND(ERROR_BUSY, device_or_resource_busy);
    157     MAP_ERR_TO_COND(ERROR_BUSY_DRIVE, device_or_resource_busy);
    158     MAP_ERR_TO_COND(ERROR_CANNOT_MAKE, permission_denied);
    159     MAP_ERR_TO_COND(ERROR_CANTOPEN, io_error);
    160     MAP_ERR_TO_COND(ERROR_CANTREAD, io_error);
    161     MAP_ERR_TO_COND(ERROR_CANTWRITE, io_error);
    162     MAP_ERR_TO_COND(ERROR_CURRENT_DIRECTORY, permission_denied);
    163     MAP_ERR_TO_COND(ERROR_DEV_NOT_EXIST, no_such_device);
    164     MAP_ERR_TO_COND(ERROR_DEVICE_IN_USE, device_or_resource_busy);
    165     MAP_ERR_TO_COND(ERROR_DIR_NOT_EMPTY, directory_not_empty);
    166     MAP_ERR_TO_COND(ERROR_DIRECTORY, invalid_argument);
    167     MAP_ERR_TO_COND(ERROR_DISK_FULL, no_space_on_device);
    168     MAP_ERR_TO_COND(ERROR_FILE_EXISTS, file_exists);
    169     MAP_ERR_TO_COND(ERROR_FILE_NOT_FOUND, no_such_file_or_directory);
    170     MAP_ERR_TO_COND(ERROR_HANDLE_DISK_FULL, no_space_on_device);
    171     MAP_ERR_TO_COND(ERROR_INVALID_ACCESS, permission_denied);
    172     MAP_ERR_TO_COND(ERROR_INVALID_DRIVE, no_such_device);
    173     MAP_ERR_TO_COND(ERROR_INVALID_FUNCTION, function_not_supported);
    174     MAP_ERR_TO_COND(ERROR_INVALID_HANDLE, invalid_argument);
    175     MAP_ERR_TO_COND(ERROR_INVALID_NAME, invalid_argument);
    176     MAP_ERR_TO_COND(ERROR_LOCK_VIOLATION, no_lock_available);
    177     MAP_ERR_TO_COND(ERROR_LOCKED, no_lock_available);
    178     MAP_ERR_TO_COND(ERROR_NEGATIVE_SEEK, invalid_argument);
    179     MAP_ERR_TO_COND(ERROR_NOACCESS, permission_denied);
    180     MAP_ERR_TO_COND(ERROR_NOT_ENOUGH_MEMORY, not_enough_memory);
    181     MAP_ERR_TO_COND(ERROR_NOT_READY, resource_unavailable_try_again);
    182     MAP_ERR_TO_COND(ERROR_OPEN_FAILED, io_error);
    183     MAP_ERR_TO_COND(ERROR_OPEN_FILES, device_or_resource_busy);
    184     MAP_ERR_TO_COND(ERROR_OUTOFMEMORY, not_enough_memory);
    185     MAP_ERR_TO_COND(ERROR_PATH_NOT_FOUND, no_such_file_or_directory);
    186     MAP_ERR_TO_COND(ERROR_BAD_NETPATH, no_such_file_or_directory);
    187     MAP_ERR_TO_COND(ERROR_READ_FAULT, io_error);
    188     MAP_ERR_TO_COND(ERROR_RETRY, resource_unavailable_try_again);
    189     MAP_ERR_TO_COND(ERROR_SEEK, io_error);
    190     MAP_ERR_TO_COND(ERROR_SHARING_VIOLATION, permission_denied);
    191     MAP_ERR_TO_COND(ERROR_TOO_MANY_OPEN_FILES, too_many_files_open);
    192     MAP_ERR_TO_COND(ERROR_WRITE_FAULT, io_error);
    193     MAP_ERR_TO_COND(ERROR_WRITE_PROTECT, permission_denied);
    194     MAP_ERR_TO_COND(WSAEACCES, permission_denied);
    195     MAP_ERR_TO_COND(WSAEBADF, bad_file_descriptor);
    196     MAP_ERR_TO_COND(WSAEFAULT, bad_address);
    197     MAP_ERR_TO_COND(WSAEINTR, interrupted);
    198     MAP_ERR_TO_COND(WSAEINVAL, invalid_argument);
    199     MAP_ERR_TO_COND(WSAEMFILE, too_many_files_open);
    200     MAP_ERR_TO_COND(WSAENAMETOOLONG, filename_too_long);
    201   default:
    202     return std::error_code(EV, std::system_category());
    203   }
    204 }
    205 
    206 #endif
    207