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/Signals.h"
22 #include "llvm/Support/Threading.h"
23 #include "llvm/Support/raw_ostream.h"
24 #include <cassert>
25 #include <cstdlib>
26 
27 #if defined(HAVE_UNISTD_H)
28 # include <unistd.h>
29 #endif
30 #if defined(_MSC_VER)
31 # include <io.h>
32 # include <fcntl.h>
33 #endif
34 
35 using namespace llvm;
36 
37 static fatal_error_handler_t ErrorHandler = 0;
38 static void *ErrorHandlerUserData = 0;
39 
40 void llvm::install_fatal_error_handler(fatal_error_handler_t handler,
41                                        void *user_data) {
42   assert(!llvm_is_multithreaded() &&
43          "Cannot register error handlers after starting multithreaded mode!\n");
44   assert(!ErrorHandler && "Error handler already registered!\n");
45   ErrorHandler = handler;
46   ErrorHandlerUserData = user_data;
47 }
48 
49 void llvm::remove_fatal_error_handler() {
50   ErrorHandler = 0;
51 }
52 
53 void llvm::report_fatal_error(const char *Reason, bool GenCrashDiag) {
54   report_fatal_error(Twine(Reason), GenCrashDiag);
55 }
56 
57 void llvm::report_fatal_error(const std::string &Reason, bool GenCrashDiag) {
58   report_fatal_error(Twine(Reason), GenCrashDiag);
59 }
60 
61 void llvm::report_fatal_error(StringRef Reason, bool GenCrashDiag) {
62   report_fatal_error(Twine(Reason), GenCrashDiag);
63 }
64 
65 void llvm::report_fatal_error(const Twine &Reason, bool GenCrashDiag) {
66   if (ErrorHandler) {
67     ErrorHandler(ErrorHandlerUserData, Reason.str(), GenCrashDiag);
68   } else {
69     // Blast the result out to stderr.  We don't try hard to make sure this
70     // succeeds (e.g. handling EINTR) and we can't use errs() here because
71     // raw ostreams can call report_fatal_error.
72     SmallVector<char, 64> Buffer;
73     raw_svector_ostream OS(Buffer);
74     OS << "LLVM ERROR: " << Reason << "\n";
75     StringRef MessageStr = OS.str();
76     ssize_t written = ::write(2, MessageStr.data(), MessageStr.size());
77     (void)written; // If something went wrong, we deliberately just give up.
78   }
79 
80   // If we reached here, we are failing ungracefully. Run the interrupt handlers
81   // to make sure any special cleanups get done, in particular that we remove
82   // files registered with RemoveFileOnSignal.
83   sys::RunInterruptHandlers();
84 
85   exit(1);
86 }
87 
88 void llvm::llvm_unreachable_internal(const char *msg, const char *file,
89                                      unsigned line) {
90   // This code intentionally doesn't call the ErrorHandler callback, because
91   // llvm_unreachable is intended to be used to indicate "impossible"
92   // situations, and not legitimate runtime errors.
93   if (msg)
94     dbgs() << msg << "\n";
95   dbgs() << "UNREACHABLE executed";
96   if (file)
97     dbgs() << " at " << file << ":" << line;
98   dbgs() << "!\n";
99   abort();
100 #ifdef LLVM_BUILTIN_UNREACHABLE
101   // Windows systems and possibly others don't declare abort() to be noreturn,
102   // so use the unreachable builtin to avoid a Clang self-host warning.
103   LLVM_BUILTIN_UNREACHABLE;
104 #endif
105 }
106 
107 static void bindingsErrorHandler(void *user_data, const std::string& reason,
108                                  bool gen_crash_diag) {
109   LLVMFatalErrorHandler handler =
110       LLVM_EXTENSION reinterpret_cast<LLVMFatalErrorHandler>(user_data);
111   handler(reason.c_str());
112 }
113 
114 void LLVMInstallFatalErrorHandler(LLVMFatalErrorHandler Handler) {
115   install_fatal_error_handler(bindingsErrorHandler,
116                               LLVM_EXTENSION reinterpret_cast<void *>(Handler));
117 }
118 
119 void LLVMResetFatalErrorHandler() {
120   remove_fatal_error_handler();
121 }
122