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/ADT/Twine.h"
16 #include "llvm/Support/Debug.h"
17 #include "llvm/Support/ErrorHandling.h"
18 #include "llvm/Support/raw_ostream.h"
19 #include "llvm/System/Signals.h"
20 #include "llvm/System/Threading.h"
21 #include "llvm/ADT/SmallVector.h"
22 #include "llvm/Config/config.h"
23 #include <cassert>
24 #include <cstdlib>
25 
26 #if defined(HAVE_UNISTD_H)
27 # include <unistd.h>
28 #endif
29 #if defined(_MSC_VER)
30 # include <io.h>
31 # include <fcntl.h>
32 #endif
33 
34 using namespace llvm;
35 using namespace std;
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) {
54   report_fatal_error(Twine(Reason));
55 }
56 
57 void llvm::report_fatal_error(const std::string &Reason) {
58   report_fatal_error(Twine(Reason));
59 }
60 
61 void llvm::report_fatal_error(const Twine &Reason) {
62   if (ErrorHandler) {
63     ErrorHandler(ErrorHandlerUserData, Reason.str());
64   } else {
65     // Blast the result out to stderr.  We don't try hard to make sure this
66     // succeeds (e.g. handling EINTR) and we can't use errs() here because
67     // raw ostreams can call report_fatal_error.
68     SmallVector<char, 64> Buffer;
69     raw_svector_ostream OS(Buffer);
70     OS << "LLVM ERROR: " << Reason << "\n";
71     StringRef MessageStr = OS.str();
72     ssize_t written = ::write(2, MessageStr.data(), MessageStr.size());
73     (void)written; // If something went wrong, we deliberately just give up.
74   }
75 
76   // If we reached here, we are failing ungracefully. Run the interrupt handlers
77   // to make sure any special cleanups get done, in particular that we remove
78   // files registered with RemoveFileOnSignal.
79   sys::RunInterruptHandlers();
80 
81   exit(1);
82 }
83 
84 void llvm::llvm_unreachable_internal(const char *msg, const char *file,
85                                      unsigned line) {
86   // This code intentionally doesn't call the ErrorHandler callback, because
87   // llvm_unreachable is intended to be used to indicate "impossible"
88   // situations, and not legitimate runtime errors.
89   if (msg)
90     dbgs() << msg << "\n";
91   dbgs() << "UNREACHABLE executed";
92   if (file)
93     dbgs() << " at " << file << ":" << line;
94   dbgs() << "!\n";
95   abort();
96 }
97