1 //===----- lib/Support/Error.cpp - Error and associated utilities ---------===//
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 #include "llvm/Support/Error.h"
10 #include "llvm/ADT/SmallVector.h"
11 #include "llvm/ADT/StringExtras.h"
12 #include "llvm/ADT/Twine.h"
13 #include "llvm/Support/ErrorHandling.h"
14 #include <system_error>
15 
16 using namespace llvm;
17 
18 namespace {
19 
20   enum class ErrorErrorCode : int {
21     MultipleErrors = 1,
22     FileError,
23     InconvertibleError
24   };
25 
26   // FIXME: This class is only here to support the transition to llvm::Error. It
27   // will be removed once this transition is complete. Clients should prefer to
28   // deal with the Error value directly, rather than converting to error_code.
29   class ErrorErrorCategory : public std::error_category {
30   public:
31     const char *name() const noexcept override { return "Error"; }
32 
33     std::string message(int condition) const override {
34       switch (static_cast<ErrorErrorCode>(condition)) {
35       case ErrorErrorCode::MultipleErrors:
36         return "Multiple errors";
37       case ErrorErrorCode::InconvertibleError:
38         return "Inconvertible error value. An error has occurred that could "
39                "not be converted to a known std::error_code. Please file a "
40                "bug.";
41       case ErrorErrorCode::FileError:
42           return "A file error occurred.";
43       }
44       llvm_unreachable("Unhandled error code");
45     }
46   };
47 
48 }
49 
50 ErrorErrorCategory &getErrorErrorCat() {
51   static ErrorErrorCategory ErrorErrorCat;
52   return ErrorErrorCat;
53 }
54 
55 namespace llvm {
56 
57 void ErrorInfoBase::anchor() {}
58 char ErrorInfoBase::ID = 0;
59 char ErrorList::ID = 0;
60 void ECError::anchor() {}
61 char ECError::ID = 0;
62 char StringError::ID = 0;
63 char FileError::ID = 0;
64 
65 void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner) {
66   if (!E)
67     return;
68   OS << ErrorBanner;
69   handleAllErrors(std::move(E), [&](const ErrorInfoBase &EI) {
70     EI.log(OS);
71     OS << "\n";
72   });
73 }
74 
75 /// Write all error messages (if any) in E to a string. The newline character
76 /// is used to separate error messages.
77 std::string toString(Error E) {
78   SmallVector<std::string, 2> Errors;
79   handleAllErrors(std::move(E), [&Errors](const ErrorInfoBase &EI) {
80     Errors.push_back(EI.message());
81   });
82   return join(Errors.begin(), Errors.end(), "\n");
83 }
84 
85 std::error_code ErrorList::convertToErrorCode() const {
86   return std::error_code(static_cast<int>(ErrorErrorCode::MultipleErrors),
87                          getErrorErrorCat());
88 }
89 
90 std::error_code inconvertibleErrorCode() {
91   return std::error_code(static_cast<int>(ErrorErrorCode::InconvertibleError),
92                          getErrorErrorCat());
93 }
94 
95 std::error_code FileError::convertToErrorCode() const {
96   std::error_code NestedEC = Err->convertToErrorCode();
97   if (NestedEC == inconvertibleErrorCode())
98     return std::error_code(static_cast<int>(ErrorErrorCode::FileError),
99                            getErrorErrorCat());
100   return NestedEC;
101 }
102 
103 Error errorCodeToError(std::error_code EC) {
104   if (!EC)
105     return Error::success();
106   return Error(std::make_unique<ECError>(ECError(EC)));
107 }
108 
109 std::error_code errorToErrorCode(Error Err) {
110   std::error_code EC;
111   handleAllErrors(std::move(Err), [&](const ErrorInfoBase &EI) {
112     EC = EI.convertToErrorCode();
113   });
114   if (EC == inconvertibleErrorCode())
115     report_fatal_error(Twine(EC.message()));
116   return EC;
117 }
118 
119 #if LLVM_ENABLE_ABI_BREAKING_CHECKS
120 void Error::fatalUncheckedError() const {
121   dbgs() << "Program aborted due to an unhandled Error:\n";
122   if (getPtr()) {
123     getPtr()->log(dbgs());
124     dbgs() << "\n";
125   }else
126     dbgs() << "Error value was Success. (Note: Success values must still be "
127               "checked prior to being destroyed).\n";
128   abort();
129 }
130 #endif
131 
132 StringError::StringError(std::error_code EC, const Twine &S)
133     : Msg(S.str()), EC(EC) {}
134 
135 StringError::StringError(const Twine &S, std::error_code EC)
136     : Msg(S.str()), EC(EC), PrintMsgOnly(true) {}
137 
138 void StringError::log(raw_ostream &OS) const {
139   if (PrintMsgOnly) {
140     OS << Msg;
141   } else {
142     OS << EC.message();
143     if (!Msg.empty())
144       OS << (" " + Msg);
145   }
146 }
147 
148 std::error_code StringError::convertToErrorCode() const {
149   return EC;
150 }
151 
152 Error createStringError(std::error_code EC, char const *Msg) {
153   return make_error<StringError>(Msg, EC);
154 }
155 
156 void report_fatal_error(Error Err, bool GenCrashDiag) {
157   assert(Err && "report_fatal_error called with success value");
158   std::string ErrMsg;
159   {
160     raw_string_ostream ErrStream(ErrMsg);
161     logAllUnhandledErrors(std::move(Err), ErrStream);
162   }
163   report_fatal_error(Twine(ErrMsg), GenCrashDiag);
164 }
165 
166 } // end namespace llvm
167 
168 LLVMErrorTypeId LLVMGetErrorTypeId(LLVMErrorRef Err) {
169   return reinterpret_cast<ErrorInfoBase *>(Err)->dynamicClassID();
170 }
171 
172 void LLVMConsumeError(LLVMErrorRef Err) { consumeError(unwrap(Err)); }
173 
174 char *LLVMGetErrorMessage(LLVMErrorRef Err) {
175   std::string Tmp = toString(unwrap(Err));
176   char *ErrMsg = new char[Tmp.size() + 1];
177   memcpy(ErrMsg, Tmp.data(), Tmp.size());
178   ErrMsg[Tmp.size()] = '\0';
179   return ErrMsg;
180 }
181 
182 void LLVMDisposeErrorMessage(char *ErrMsg) { delete[] ErrMsg; }
183 
184 LLVMErrorTypeId LLVMGetStringErrorTypeId() {
185   return reinterpret_cast<void *>(&StringError::ID);
186 }
187 
188 LLVMErrorRef LLVMCreateStringError(const char *ErrMsg) {
189   return wrap(make_error<StringError>(ErrMsg, inconvertibleErrorCode()));
190 }
191