1 //===----- lib/Support/Error.cpp - Error and associated utilities ---------===//
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 #include "llvm/Support/Error.h"
11 #include "llvm/ADT/Twine.h"
12 #include "llvm/Support/ErrorHandling.h"
13 #include "llvm/Support/ManagedStatic.h"
14 
15 
16 using namespace llvm;
17 
18 namespace {
19 
20   enum class ErrorErrorCode : int {
21     MultipleErrors = 1,
22     InconvertibleError
23   };
24 
25   // FIXME: This class is only here to support the transition to llvm::Error. It
26   // will be removed once this transition is complete. Clients should prefer to
27   // deal with the Error value directly, rather than converting to error_code.
28   class ErrorErrorCategory : public std::error_category {
29   public:
30     const char *name() const LLVM_NOEXCEPT override { return "Error"; }
31 
32     std::string message(int condition) const override {
33       switch (static_cast<ErrorErrorCode>(condition)) {
34       case ErrorErrorCode::MultipleErrors:
35         return "Multiple errors";
36       case ErrorErrorCode::InconvertibleError:
37         return "Inconvertible error value. An error has occurred that could "
38                "not be converted to a known std::error_code. Please file a "
39                "bug.";
40       }
41       llvm_unreachable("Unhandled error code");
42     }
43   };
44 
45 }
46 
47 static ManagedStatic<ErrorErrorCategory> ErrorErrorCat;
48 
49 namespace llvm {
50 
51 void ErrorInfoBase::anchor() {}
52 char ErrorInfoBase::ID = 0;
53 char ErrorList::ID = 0;
54 char ECError::ID = 0;
55 char StringError::ID = 0;
56 
57 
58 std::error_code ErrorList::convertToErrorCode() const {
59   return std::error_code(static_cast<int>(ErrorErrorCode::MultipleErrors),
60                          *ErrorErrorCat);
61 }
62 
63 std::error_code inconvertibleErrorCode() {
64   return std::error_code(static_cast<int>(ErrorErrorCode::InconvertibleError),
65                          *ErrorErrorCat);
66 }
67 
68 Error errorCodeToError(std::error_code EC) {
69   if (!EC)
70     return Error::success();
71   return Error(llvm::make_unique<ECError>(ECError(EC)));
72 }
73 
74 std::error_code errorToErrorCode(Error Err) {
75   std::error_code EC;
76   handleAllErrors(std::move(Err), [&](const ErrorInfoBase &EI) {
77     EC = EI.convertToErrorCode();
78   });
79   if (EC == inconvertibleErrorCode())
80     report_fatal_error(EC.message());
81   return EC;
82 }
83 
84 StringError::StringError(const Twine &S, std::error_code EC)
85     : Msg(S.str()), EC(EC) {}
86 
87 void StringError::log(raw_ostream &OS) const { OS << Msg; }
88 
89 std::error_code StringError::convertToErrorCode() const {
90   return EC;
91 }
92 
93 }
94