File: | lib/Object/Error.cpp |
Warning: | line 94, column 10 Moved-from object 'Err' is moved |
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1 | //===- Error.cpp - system_error extensions for Object -----------*- C++ -*-===// | |||
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 | // This defines a new error_category for the Object library. | |||
10 | // | |||
11 | //===----------------------------------------------------------------------===// | |||
12 | ||||
13 | #include "llvm/Object/Error.h" | |||
14 | #include "llvm/Support/ErrorHandling.h" | |||
15 | #include "llvm/Support/ManagedStatic.h" | |||
16 | ||||
17 | using namespace llvm; | |||
18 | using namespace object; | |||
19 | ||||
20 | namespace { | |||
21 | // FIXME: This class is only here to support the transition to llvm::Error. It | |||
22 | // will be removed once this transition is complete. Clients should prefer to | |||
23 | // deal with the Error value directly, rather than converting to error_code. | |||
24 | class _object_error_category : public std::error_category { | |||
25 | public: | |||
26 | const char* name() const noexcept override; | |||
27 | std::string message(int ev) const override; | |||
28 | }; | |||
29 | } | |||
30 | ||||
31 | const char *_object_error_category::name() const noexcept { | |||
32 | return "llvm.object"; | |||
33 | } | |||
34 | ||||
35 | std::string _object_error_category::message(int EV) const { | |||
36 | object_error E = static_cast<object_error>(EV); | |||
37 | switch (E) { | |||
38 | case object_error::arch_not_found: | |||
39 | return "No object file for requested architecture"; | |||
40 | case object_error::invalid_file_type: | |||
41 | return "The file was not recognized as a valid object file"; | |||
42 | case object_error::parse_failed: | |||
43 | return "Invalid data was encountered while parsing the file"; | |||
44 | case object_error::unexpected_eof: | |||
45 | return "The end of the file was unexpectedly encountered"; | |||
46 | case object_error::string_table_non_null_end: | |||
47 | return "String table must end with a null terminator"; | |||
48 | case object_error::invalid_section_index: | |||
49 | return "Invalid section index"; | |||
50 | case object_error::bitcode_section_not_found: | |||
51 | return "Bitcode section not found in object file"; | |||
52 | case object_error::invalid_symbol_index: | |||
53 | return "Invalid symbol index"; | |||
54 | } | |||
55 | llvm_unreachable("An enumerator of object_error does not have a message "::llvm::llvm_unreachable_internal("An enumerator of object_error does not have a message " "defined.", "/build/llvm-toolchain-snapshot-9~svn362543/lib/Object/Error.cpp" , 56) | |||
56 | "defined.")::llvm::llvm_unreachable_internal("An enumerator of object_error does not have a message " "defined.", "/build/llvm-toolchain-snapshot-9~svn362543/lib/Object/Error.cpp" , 56); | |||
57 | } | |||
58 | ||||
59 | void BinaryError::anchor() {} | |||
60 | char BinaryError::ID = 0; | |||
61 | char GenericBinaryError::ID = 0; | |||
62 | ||||
63 | GenericBinaryError::GenericBinaryError(Twine Msg) : Msg(Msg.str()) {} | |||
64 | ||||
65 | GenericBinaryError::GenericBinaryError(Twine Msg, object_error ECOverride) | |||
66 | : Msg(Msg.str()) { | |||
67 | setErrorCode(make_error_code(ECOverride)); | |||
68 | } | |||
69 | ||||
70 | void GenericBinaryError::log(raw_ostream &OS) const { | |||
71 | OS << Msg; | |||
72 | } | |||
73 | ||||
74 | static ManagedStatic<_object_error_category> error_category; | |||
75 | ||||
76 | const std::error_category &object::object_category() { | |||
77 | return *error_category; | |||
78 | } | |||
79 | ||||
80 | llvm::Error llvm::object::isNotObjectErrorInvalidFileType(llvm::Error Err) { | |||
81 | if (auto Err2 = | |||
82 | handleErrors(std::move(Err), [](std::unique_ptr<ECError> M) -> Error { | |||
| ||||
83 | // Try to handle 'M'. If successful, return a success value from | |||
84 | // the handler. | |||
85 | if (M->convertToErrorCode() == object_error::invalid_file_type) | |||
86 | return Error::success(); | |||
87 | ||||
88 | // We failed to handle 'M' - return it from the handler. | |||
89 | // This value will be passed back from catchErrors and | |||
90 | // wind up in Err2, where it will be returned from this function. | |||
91 | return Error(std::move(M)); | |||
92 | })) | |||
93 | return Err2; | |||
94 | return Err; | |||
| ||||
95 | } |
1 | //===- llvm/Support/Error.h - Recoverable error handling --------*- C++ -*-===// |
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 | // This file defines an API used to report recoverable errors. |
10 | // |
11 | //===----------------------------------------------------------------------===// |
12 | |
13 | #ifndef LLVM_SUPPORT_ERROR_H |
14 | #define LLVM_SUPPORT_ERROR_H |
15 | |
16 | #include "llvm-c/Error.h" |
17 | #include "llvm/ADT/STLExtras.h" |
18 | #include "llvm/ADT/SmallVector.h" |
19 | #include "llvm/ADT/StringExtras.h" |
20 | #include "llvm/ADT/Twine.h" |
21 | #include "llvm/Config/abi-breaking.h" |
22 | #include "llvm/Support/AlignOf.h" |
23 | #include "llvm/Support/Compiler.h" |
24 | #include "llvm/Support/Debug.h" |
25 | #include "llvm/Support/ErrorHandling.h" |
26 | #include "llvm/Support/ErrorOr.h" |
27 | #include "llvm/Support/Format.h" |
28 | #include "llvm/Support/raw_ostream.h" |
29 | #include <algorithm> |
30 | #include <cassert> |
31 | #include <cstdint> |
32 | #include <cstdlib> |
33 | #include <functional> |
34 | #include <memory> |
35 | #include <new> |
36 | #include <string> |
37 | #include <system_error> |
38 | #include <type_traits> |
39 | #include <utility> |
40 | #include <vector> |
41 | |
42 | namespace llvm { |
43 | |
44 | class ErrorSuccess; |
45 | |
46 | /// Base class for error info classes. Do not extend this directly: Extend |
47 | /// the ErrorInfo template subclass instead. |
48 | class ErrorInfoBase { |
49 | public: |
50 | virtual ~ErrorInfoBase() = default; |
51 | |
52 | /// Print an error message to an output stream. |
53 | virtual void log(raw_ostream &OS) const = 0; |
54 | |
55 | /// Return the error message as a string. |
56 | virtual std::string message() const { |
57 | std::string Msg; |
58 | raw_string_ostream OS(Msg); |
59 | log(OS); |
60 | return OS.str(); |
61 | } |
62 | |
63 | /// Convert this error to a std::error_code. |
64 | /// |
65 | /// This is a temporary crutch to enable interaction with code still |
66 | /// using std::error_code. It will be removed in the future. |
67 | virtual std::error_code convertToErrorCode() const = 0; |
68 | |
69 | // Returns the class ID for this type. |
70 | static const void *classID() { return &ID; } |
71 | |
72 | // Returns the class ID for the dynamic type of this ErrorInfoBase instance. |
73 | virtual const void *dynamicClassID() const = 0; |
74 | |
75 | // Check whether this instance is a subclass of the class identified by |
76 | // ClassID. |
77 | virtual bool isA(const void *const ClassID) const { |
78 | return ClassID == classID(); |
79 | } |
80 | |
81 | // Check whether this instance is a subclass of ErrorInfoT. |
82 | template <typename ErrorInfoT> bool isA() const { |
83 | return isA(ErrorInfoT::classID()); |
84 | } |
85 | |
86 | private: |
87 | virtual void anchor(); |
88 | |
89 | static char ID; |
90 | }; |
91 | |
92 | /// Lightweight error class with error context and mandatory checking. |
93 | /// |
94 | /// Instances of this class wrap a ErrorInfoBase pointer. Failure states |
95 | /// are represented by setting the pointer to a ErrorInfoBase subclass |
96 | /// instance containing information describing the failure. Success is |
97 | /// represented by a null pointer value. |
98 | /// |
99 | /// Instances of Error also contains a 'Checked' flag, which must be set |
100 | /// before the destructor is called, otherwise the destructor will trigger a |
101 | /// runtime error. This enforces at runtime the requirement that all Error |
102 | /// instances be checked or returned to the caller. |
103 | /// |
104 | /// There are two ways to set the checked flag, depending on what state the |
105 | /// Error instance is in. For Error instances indicating success, it |
106 | /// is sufficient to invoke the boolean conversion operator. E.g.: |
107 | /// |
108 | /// @code{.cpp} |
109 | /// Error foo(<...>); |
110 | /// |
111 | /// if (auto E = foo(<...>)) |
112 | /// return E; // <- Return E if it is in the error state. |
113 | /// // We have verified that E was in the success state. It can now be safely |
114 | /// // destroyed. |
115 | /// @endcode |
116 | /// |
117 | /// A success value *can not* be dropped. For example, just calling 'foo(<...>)' |
118 | /// without testing the return value will raise a runtime error, even if foo |
119 | /// returns success. |
120 | /// |
121 | /// For Error instances representing failure, you must use either the |
122 | /// handleErrors or handleAllErrors function with a typed handler. E.g.: |
123 | /// |
124 | /// @code{.cpp} |
125 | /// class MyErrorInfo : public ErrorInfo<MyErrorInfo> { |
126 | /// // Custom error info. |
127 | /// }; |
128 | /// |
129 | /// Error foo(<...>) { return make_error<MyErrorInfo>(...); } |
130 | /// |
131 | /// auto E = foo(<...>); // <- foo returns failure with MyErrorInfo. |
132 | /// auto NewE = |
133 | /// handleErrors(E, |
134 | /// [](const MyErrorInfo &M) { |
135 | /// // Deal with the error. |
136 | /// }, |
137 | /// [](std::unique_ptr<OtherError> M) -> Error { |
138 | /// if (canHandle(*M)) { |
139 | /// // handle error. |
140 | /// return Error::success(); |
141 | /// } |
142 | /// // Couldn't handle this error instance. Pass it up the stack. |
143 | /// return Error(std::move(M)); |
144 | /// ); |
145 | /// // Note - we must check or return NewE in case any of the handlers |
146 | /// // returned a new error. |
147 | /// @endcode |
148 | /// |
149 | /// The handleAllErrors function is identical to handleErrors, except |
150 | /// that it has a void return type, and requires all errors to be handled and |
151 | /// no new errors be returned. It prevents errors (assuming they can all be |
152 | /// handled) from having to be bubbled all the way to the top-level. |
153 | /// |
154 | /// *All* Error instances must be checked before destruction, even if |
155 | /// they're moved-assigned or constructed from Success values that have already |
156 | /// been checked. This enforces checking through all levels of the call stack. |
157 | class LLVM_NODISCARD[[clang::warn_unused_result]] Error { |
158 | // Both ErrorList and FileError need to be able to yank ErrorInfoBase |
159 | // pointers out of this class to add to the error list. |
160 | friend class ErrorList; |
161 | friend class FileError; |
162 | |
163 | // handleErrors needs to be able to set the Checked flag. |
164 | template <typename... HandlerTs> |
165 | friend Error handleErrors(Error E, HandlerTs &&... Handlers); |
166 | |
167 | // Expected<T> needs to be able to steal the payload when constructed from an |
168 | // error. |
169 | template <typename T> friend class Expected; |
170 | |
171 | // wrap needs to be able to steal the payload. |
172 | friend LLVMErrorRef wrap(Error); |
173 | |
174 | protected: |
175 | /// Create a success value. Prefer using 'Error::success()' for readability |
176 | Error() { |
177 | setPtr(nullptr); |
178 | setChecked(false); |
179 | } |
180 | |
181 | public: |
182 | /// Create a success value. |
183 | static ErrorSuccess success(); |
184 | |
185 | // Errors are not copy-constructable. |
186 | Error(const Error &Other) = delete; |
187 | |
188 | /// Move-construct an error value. The newly constructed error is considered |
189 | /// unchecked, even if the source error had been checked. The original error |
190 | /// becomes a checked Success value, regardless of its original state. |
191 | Error(Error &&Other) { |
192 | setChecked(true); |
193 | *this = std::move(Other); |
194 | } |
195 | |
196 | /// Create an error value. Prefer using the 'make_error' function, but |
197 | /// this constructor can be useful when "re-throwing" errors from handlers. |
198 | Error(std::unique_ptr<ErrorInfoBase> Payload) { |
199 | setPtr(Payload.release()); |
200 | setChecked(false); |
201 | } |
202 | |
203 | // Errors are not copy-assignable. |
204 | Error &operator=(const Error &Other) = delete; |
205 | |
206 | /// Move-assign an error value. The current error must represent success, you |
207 | /// you cannot overwrite an unhandled error. The current error is then |
208 | /// considered unchecked. The source error becomes a checked success value, |
209 | /// regardless of its original state. |
210 | Error &operator=(Error &&Other) { |
211 | // Don't allow overwriting of unchecked values. |
212 | assertIsChecked(); |
213 | setPtr(Other.getPtr()); |
214 | |
215 | // This Error is unchecked, even if the source error was checked. |
216 | setChecked(false); |
217 | |
218 | // Null out Other's payload and set its checked bit. |
219 | Other.setPtr(nullptr); |
220 | Other.setChecked(true); |
221 | |
222 | return *this; |
223 | } |
224 | |
225 | /// Destroy a Error. Fails with a call to abort() if the error is |
226 | /// unchecked. |
227 | ~Error() { |
228 | assertIsChecked(); |
229 | delete getPtr(); |
230 | } |
231 | |
232 | /// Bool conversion. Returns true if this Error is in a failure state, |
233 | /// and false if it is in an accept state. If the error is in a Success state |
234 | /// it will be considered checked. |
235 | explicit operator bool() { |
236 | setChecked(getPtr() == nullptr); |
237 | return getPtr() != nullptr; |
238 | } |
239 | |
240 | /// Check whether one error is a subclass of another. |
241 | template <typename ErrT> bool isA() const { |
242 | return getPtr() && getPtr()->isA(ErrT::classID()); |
243 | } |
244 | |
245 | /// Returns the dynamic class id of this error, or null if this is a success |
246 | /// value. |
247 | const void* dynamicClassID() const { |
248 | if (!getPtr()) |
249 | return nullptr; |
250 | return getPtr()->dynamicClassID(); |
251 | } |
252 | |
253 | private: |
254 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS1 |
255 | // assertIsChecked() happens very frequently, but under normal circumstances |
256 | // is supposed to be a no-op. So we want it to be inlined, but having a bunch |
257 | // of debug prints can cause the function to be too large for inlining. So |
258 | // it's important that we define this function out of line so that it can't be |
259 | // inlined. |
260 | LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn)) |
261 | void fatalUncheckedError() const; |
262 | #endif |
263 | |
264 | void assertIsChecked() { |
265 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS1 |
266 | if (LLVM_UNLIKELY(!getChecked() || getPtr())__builtin_expect((bool)(!getChecked() || getPtr()), false)) |
267 | fatalUncheckedError(); |
268 | #endif |
269 | } |
270 | |
271 | ErrorInfoBase *getPtr() const { |
272 | return reinterpret_cast<ErrorInfoBase*>( |
273 | reinterpret_cast<uintptr_t>(Payload) & |
274 | ~static_cast<uintptr_t>(0x1)); |
275 | } |
276 | |
277 | void setPtr(ErrorInfoBase *EI) { |
278 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS1 |
279 | Payload = reinterpret_cast<ErrorInfoBase*>( |
280 | (reinterpret_cast<uintptr_t>(EI) & |
281 | ~static_cast<uintptr_t>(0x1)) | |
282 | (reinterpret_cast<uintptr_t>(Payload) & 0x1)); |
283 | #else |
284 | Payload = EI; |
285 | #endif |
286 | } |
287 | |
288 | bool getChecked() const { |
289 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS1 |
290 | return (reinterpret_cast<uintptr_t>(Payload) & 0x1) == 0; |
291 | #else |
292 | return true; |
293 | #endif |
294 | } |
295 | |
296 | void setChecked(bool V) { |
297 | Payload = reinterpret_cast<ErrorInfoBase*>( |
298 | (reinterpret_cast<uintptr_t>(Payload) & |
299 | ~static_cast<uintptr_t>(0x1)) | |
300 | (V ? 0 : 1)); |
301 | } |
302 | |
303 | std::unique_ptr<ErrorInfoBase> takePayload() { |
304 | std::unique_ptr<ErrorInfoBase> Tmp(getPtr()); |
305 | setPtr(nullptr); |
306 | setChecked(true); |
307 | return Tmp; |
308 | } |
309 | |
310 | friend raw_ostream &operator<<(raw_ostream &OS, const Error &E) { |
311 | if (auto P = E.getPtr()) |
312 | P->log(OS); |
313 | else |
314 | OS << "success"; |
315 | return OS; |
316 | } |
317 | |
318 | ErrorInfoBase *Payload = nullptr; |
319 | }; |
320 | |
321 | /// Subclass of Error for the sole purpose of identifying the success path in |
322 | /// the type system. This allows to catch invalid conversion to Expected<T> at |
323 | /// compile time. |
324 | class ErrorSuccess final : public Error {}; |
325 | |
326 | inline ErrorSuccess Error::success() { return ErrorSuccess(); } |
327 | |
328 | /// Make a Error instance representing failure using the given error info |
329 | /// type. |
330 | template <typename ErrT, typename... ArgTs> Error make_error(ArgTs &&... Args) { |
331 | return Error(llvm::make_unique<ErrT>(std::forward<ArgTs>(Args)...)); |
332 | } |
333 | |
334 | /// Base class for user error types. Users should declare their error types |
335 | /// like: |
336 | /// |
337 | /// class MyError : public ErrorInfo<MyError> { |
338 | /// .... |
339 | /// }; |
340 | /// |
341 | /// This class provides an implementation of the ErrorInfoBase::kind |
342 | /// method, which is used by the Error RTTI system. |
343 | template <typename ThisErrT, typename ParentErrT = ErrorInfoBase> |
344 | class ErrorInfo : public ParentErrT { |
345 | public: |
346 | using ParentErrT::ParentErrT; // inherit constructors |
347 | |
348 | static const void *classID() { return &ThisErrT::ID; } |
349 | |
350 | const void *dynamicClassID() const override { return &ThisErrT::ID; } |
351 | |
352 | bool isA(const void *const ClassID) const override { |
353 | return ClassID == classID() || ParentErrT::isA(ClassID); |
354 | } |
355 | }; |
356 | |
357 | /// Special ErrorInfo subclass representing a list of ErrorInfos. |
358 | /// Instances of this class are constructed by joinError. |
359 | class ErrorList final : public ErrorInfo<ErrorList> { |
360 | // handleErrors needs to be able to iterate the payload list of an |
361 | // ErrorList. |
362 | template <typename... HandlerTs> |
363 | friend Error handleErrors(Error E, HandlerTs &&... Handlers); |
364 | |
365 | // joinErrors is implemented in terms of join. |
366 | friend Error joinErrors(Error, Error); |
367 | |
368 | public: |
369 | void log(raw_ostream &OS) const override { |
370 | OS << "Multiple errors:\n"; |
371 | for (auto &ErrPayload : Payloads) { |
372 | ErrPayload->log(OS); |
373 | OS << "\n"; |
374 | } |
375 | } |
376 | |
377 | std::error_code convertToErrorCode() const override; |
378 | |
379 | // Used by ErrorInfo::classID. |
380 | static char ID; |
381 | |
382 | private: |
383 | ErrorList(std::unique_ptr<ErrorInfoBase> Payload1, |
384 | std::unique_ptr<ErrorInfoBase> Payload2) { |
385 | assert(!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() &&((!Payload1->isA<ErrorList>() && !Payload2-> isA<ErrorList>() && "ErrorList constructor payloads should be singleton errors" ) ? static_cast<void> (0) : __assert_fail ("!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() && \"ErrorList constructor payloads should be singleton errors\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 386, __PRETTY_FUNCTION__)) |
386 | "ErrorList constructor payloads should be singleton errors")((!Payload1->isA<ErrorList>() && !Payload2-> isA<ErrorList>() && "ErrorList constructor payloads should be singleton errors" ) ? static_cast<void> (0) : __assert_fail ("!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() && \"ErrorList constructor payloads should be singleton errors\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 386, __PRETTY_FUNCTION__)); |
387 | Payloads.push_back(std::move(Payload1)); |
388 | Payloads.push_back(std::move(Payload2)); |
389 | } |
390 | |
391 | static Error join(Error E1, Error E2) { |
392 | if (!E1) |
393 | return E2; |
394 | if (!E2) |
395 | return E1; |
396 | if (E1.isA<ErrorList>()) { |
397 | auto &E1List = static_cast<ErrorList &>(*E1.getPtr()); |
398 | if (E2.isA<ErrorList>()) { |
399 | auto E2Payload = E2.takePayload(); |
400 | auto &E2List = static_cast<ErrorList &>(*E2Payload); |
401 | for (auto &Payload : E2List.Payloads) |
402 | E1List.Payloads.push_back(std::move(Payload)); |
403 | } else |
404 | E1List.Payloads.push_back(E2.takePayload()); |
405 | |
406 | return E1; |
407 | } |
408 | if (E2.isA<ErrorList>()) { |
409 | auto &E2List = static_cast<ErrorList &>(*E2.getPtr()); |
410 | E2List.Payloads.insert(E2List.Payloads.begin(), E1.takePayload()); |
411 | return E2; |
412 | } |
413 | return Error(std::unique_ptr<ErrorList>( |
414 | new ErrorList(E1.takePayload(), E2.takePayload()))); |
415 | } |
416 | |
417 | std::vector<std::unique_ptr<ErrorInfoBase>> Payloads; |
418 | }; |
419 | |
420 | /// Concatenate errors. The resulting Error is unchecked, and contains the |
421 | /// ErrorInfo(s), if any, contained in E1, followed by the |
422 | /// ErrorInfo(s), if any, contained in E2. |
423 | inline Error joinErrors(Error E1, Error E2) { |
424 | return ErrorList::join(std::move(E1), std::move(E2)); |
425 | } |
426 | |
427 | /// Tagged union holding either a T or a Error. |
428 | /// |
429 | /// This class parallels ErrorOr, but replaces error_code with Error. Since |
430 | /// Error cannot be copied, this class replaces getError() with |
431 | /// takeError(). It also adds an bool errorIsA<ErrT>() method for testing the |
432 | /// error class type. |
433 | template <class T> class LLVM_NODISCARD[[clang::warn_unused_result]] Expected { |
434 | template <class T1> friend class ExpectedAsOutParameter; |
435 | template <class OtherT> friend class Expected; |
436 | |
437 | static const bool isRef = std::is_reference<T>::value; |
438 | |
439 | using wrap = std::reference_wrapper<typename std::remove_reference<T>::type>; |
440 | |
441 | using error_type = std::unique_ptr<ErrorInfoBase>; |
442 | |
443 | public: |
444 | using storage_type = typename std::conditional<isRef, wrap, T>::type; |
445 | using value_type = T; |
446 | |
447 | private: |
448 | using reference = typename std::remove_reference<T>::type &; |
449 | using const_reference = const typename std::remove_reference<T>::type &; |
450 | using pointer = typename std::remove_reference<T>::type *; |
451 | using const_pointer = const typename std::remove_reference<T>::type *; |
452 | |
453 | public: |
454 | /// Create an Expected<T> error value from the given Error. |
455 | Expected(Error Err) |
456 | : HasError(true) |
457 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS1 |
458 | // Expected is unchecked upon construction in Debug builds. |
459 | , Unchecked(true) |
460 | #endif |
461 | { |
462 | assert(Err && "Cannot create Expected<T> from Error success value.")((Err && "Cannot create Expected<T> from Error success value." ) ? static_cast<void> (0) : __assert_fail ("Err && \"Cannot create Expected<T> from Error success value.\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 462, __PRETTY_FUNCTION__)); |
463 | new (getErrorStorage()) error_type(Err.takePayload()); |
464 | } |
465 | |
466 | /// Forbid to convert from Error::success() implicitly, this avoids having |
467 | /// Expected<T> foo() { return Error::success(); } which compiles otherwise |
468 | /// but triggers the assertion above. |
469 | Expected(ErrorSuccess) = delete; |
470 | |
471 | /// Create an Expected<T> success value from the given OtherT value, which |
472 | /// must be convertible to T. |
473 | template <typename OtherT> |
474 | Expected(OtherT &&Val, |
475 | typename std::enable_if<std::is_convertible<OtherT, T>::value>::type |
476 | * = nullptr) |
477 | : HasError(false) |
478 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS1 |
479 | // Expected is unchecked upon construction in Debug builds. |
480 | , Unchecked(true) |
481 | #endif |
482 | { |
483 | new (getStorage()) storage_type(std::forward<OtherT>(Val)); |
484 | } |
485 | |
486 | /// Move construct an Expected<T> value. |
487 | Expected(Expected &&Other) { moveConstruct(std::move(Other)); } |
488 | |
489 | /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT |
490 | /// must be convertible to T. |
491 | template <class OtherT> |
492 | Expected(Expected<OtherT> &&Other, |
493 | typename std::enable_if<std::is_convertible<OtherT, T>::value>::type |
494 | * = nullptr) { |
495 | moveConstruct(std::move(Other)); |
496 | } |
497 | |
498 | /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT |
499 | /// isn't convertible to T. |
500 | template <class OtherT> |
501 | explicit Expected( |
502 | Expected<OtherT> &&Other, |
503 | typename std::enable_if<!std::is_convertible<OtherT, T>::value>::type * = |
504 | nullptr) { |
505 | moveConstruct(std::move(Other)); |
506 | } |
507 | |
508 | /// Move-assign from another Expected<T>. |
509 | Expected &operator=(Expected &&Other) { |
510 | moveAssign(std::move(Other)); |
511 | return *this; |
512 | } |
513 | |
514 | /// Destroy an Expected<T>. |
515 | ~Expected() { |
516 | assertIsChecked(); |
517 | if (!HasError) |
518 | getStorage()->~storage_type(); |
519 | else |
520 | getErrorStorage()->~error_type(); |
521 | } |
522 | |
523 | /// Return false if there is an error. |
524 | explicit operator bool() { |
525 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS1 |
526 | Unchecked = HasError; |
527 | #endif |
528 | return !HasError; |
529 | } |
530 | |
531 | /// Returns a reference to the stored T value. |
532 | reference get() { |
533 | assertIsChecked(); |
534 | return *getStorage(); |
535 | } |
536 | |
537 | /// Returns a const reference to the stored T value. |
538 | const_reference get() const { |
539 | assertIsChecked(); |
540 | return const_cast<Expected<T> *>(this)->get(); |
541 | } |
542 | |
543 | /// Check that this Expected<T> is an error of type ErrT. |
544 | template <typename ErrT> bool errorIsA() const { |
545 | return HasError && (*getErrorStorage())->template isA<ErrT>(); |
546 | } |
547 | |
548 | /// Take ownership of the stored error. |
549 | /// After calling this the Expected<T> is in an indeterminate state that can |
550 | /// only be safely destructed. No further calls (beside the destructor) should |
551 | /// be made on the Expected<T> vaule. |
552 | Error takeError() { |
553 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS1 |
554 | Unchecked = false; |
555 | #endif |
556 | return HasError ? Error(std::move(*getErrorStorage())) : Error::success(); |
557 | } |
558 | |
559 | /// Returns a pointer to the stored T value. |
560 | pointer operator->() { |
561 | assertIsChecked(); |
562 | return toPointer(getStorage()); |
563 | } |
564 | |
565 | /// Returns a const pointer to the stored T value. |
566 | const_pointer operator->() const { |
567 | assertIsChecked(); |
568 | return toPointer(getStorage()); |
569 | } |
570 | |
571 | /// Returns a reference to the stored T value. |
572 | reference operator*() { |
573 | assertIsChecked(); |
574 | return *getStorage(); |
575 | } |
576 | |
577 | /// Returns a const reference to the stored T value. |
578 | const_reference operator*() const { |
579 | assertIsChecked(); |
580 | return *getStorage(); |
581 | } |
582 | |
583 | private: |
584 | template <class T1> |
585 | static bool compareThisIfSameType(const T1 &a, const T1 &b) { |
586 | return &a == &b; |
587 | } |
588 | |
589 | template <class T1, class T2> |
590 | static bool compareThisIfSameType(const T1 &a, const T2 &b) { |
591 | return false; |
592 | } |
593 | |
594 | template <class OtherT> void moveConstruct(Expected<OtherT> &&Other) { |
595 | HasError = Other.HasError; |
596 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS1 |
597 | Unchecked = true; |
598 | Other.Unchecked = false; |
599 | #endif |
600 | |
601 | if (!HasError) |
602 | new (getStorage()) storage_type(std::move(*Other.getStorage())); |
603 | else |
604 | new (getErrorStorage()) error_type(std::move(*Other.getErrorStorage())); |
605 | } |
606 | |
607 | template <class OtherT> void moveAssign(Expected<OtherT> &&Other) { |
608 | assertIsChecked(); |
609 | |
610 | if (compareThisIfSameType(*this, Other)) |
611 | return; |
612 | |
613 | this->~Expected(); |
614 | new (this) Expected(std::move(Other)); |
615 | } |
616 | |
617 | pointer toPointer(pointer Val) { return Val; } |
618 | |
619 | const_pointer toPointer(const_pointer Val) const { return Val; } |
620 | |
621 | pointer toPointer(wrap *Val) { return &Val->get(); } |
622 | |
623 | const_pointer toPointer(const wrap *Val) const { return &Val->get(); } |
624 | |
625 | storage_type *getStorage() { |
626 | assert(!HasError && "Cannot get value when an error exists!")((!HasError && "Cannot get value when an error exists!" ) ? static_cast<void> (0) : __assert_fail ("!HasError && \"Cannot get value when an error exists!\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 626, __PRETTY_FUNCTION__)); |
627 | return reinterpret_cast<storage_type *>(TStorage.buffer); |
628 | } |
629 | |
630 | const storage_type *getStorage() const { |
631 | assert(!HasError && "Cannot get value when an error exists!")((!HasError && "Cannot get value when an error exists!" ) ? static_cast<void> (0) : __assert_fail ("!HasError && \"Cannot get value when an error exists!\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 631, __PRETTY_FUNCTION__)); |
632 | return reinterpret_cast<const storage_type *>(TStorage.buffer); |
633 | } |
634 | |
635 | error_type *getErrorStorage() { |
636 | assert(HasError && "Cannot get error when a value exists!")((HasError && "Cannot get error when a value exists!" ) ? static_cast<void> (0) : __assert_fail ("HasError && \"Cannot get error when a value exists!\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 636, __PRETTY_FUNCTION__)); |
637 | return reinterpret_cast<error_type *>(ErrorStorage.buffer); |
638 | } |
639 | |
640 | const error_type *getErrorStorage() const { |
641 | assert(HasError && "Cannot get error when a value exists!")((HasError && "Cannot get error when a value exists!" ) ? static_cast<void> (0) : __assert_fail ("HasError && \"Cannot get error when a value exists!\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 641, __PRETTY_FUNCTION__)); |
642 | return reinterpret_cast<const error_type *>(ErrorStorage.buffer); |
643 | } |
644 | |
645 | // Used by ExpectedAsOutParameter to reset the checked flag. |
646 | void setUnchecked() { |
647 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS1 |
648 | Unchecked = true; |
649 | #endif |
650 | } |
651 | |
652 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS1 |
653 | LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn)) |
654 | LLVM_ATTRIBUTE_NOINLINE__attribute__((noinline)) |
655 | void fatalUncheckedExpected() const { |
656 | dbgs() << "Expected<T> must be checked before access or destruction.\n"; |
657 | if (HasError) { |
658 | dbgs() << "Unchecked Expected<T> contained error:\n"; |
659 | (*getErrorStorage())->log(dbgs()); |
660 | } else |
661 | dbgs() << "Expected<T> value was in success state. (Note: Expected<T> " |
662 | "values in success mode must still be checked prior to being " |
663 | "destroyed).\n"; |
664 | abort(); |
665 | } |
666 | #endif |
667 | |
668 | void assertIsChecked() { |
669 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS1 |
670 | if (LLVM_UNLIKELY(Unchecked)__builtin_expect((bool)(Unchecked), false)) |
671 | fatalUncheckedExpected(); |
672 | #endif |
673 | } |
674 | |
675 | union { |
676 | AlignedCharArrayUnion<storage_type> TStorage; |
677 | AlignedCharArrayUnion<error_type> ErrorStorage; |
678 | }; |
679 | bool HasError : 1; |
680 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS1 |
681 | bool Unchecked : 1; |
682 | #endif |
683 | }; |
684 | |
685 | /// Report a serious error, calling any installed error handler. See |
686 | /// ErrorHandling.h. |
687 | LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn)) void report_fatal_error(Error Err, |
688 | bool gen_crash_diag = true); |
689 | |
690 | /// Report a fatal error if Err is a failure value. |
691 | /// |
692 | /// This function can be used to wrap calls to fallible functions ONLY when it |
693 | /// is known that the Error will always be a success value. E.g. |
694 | /// |
695 | /// @code{.cpp} |
696 | /// // foo only attempts the fallible operation if DoFallibleOperation is |
697 | /// // true. If DoFallibleOperation is false then foo always returns |
698 | /// // Error::success(). |
699 | /// Error foo(bool DoFallibleOperation); |
700 | /// |
701 | /// cantFail(foo(false)); |
702 | /// @endcode |
703 | inline void cantFail(Error Err, const char *Msg = nullptr) { |
704 | if (Err) { |
705 | if (!Msg) |
706 | Msg = "Failure value returned from cantFail wrapped call"; |
707 | llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 707); |
708 | } |
709 | } |
710 | |
711 | /// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and |
712 | /// returns the contained value. |
713 | /// |
714 | /// This function can be used to wrap calls to fallible functions ONLY when it |
715 | /// is known that the Error will always be a success value. E.g. |
716 | /// |
717 | /// @code{.cpp} |
718 | /// // foo only attempts the fallible operation if DoFallibleOperation is |
719 | /// // true. If DoFallibleOperation is false then foo always returns an int. |
720 | /// Expected<int> foo(bool DoFallibleOperation); |
721 | /// |
722 | /// int X = cantFail(foo(false)); |
723 | /// @endcode |
724 | template <typename T> |
725 | T cantFail(Expected<T> ValOrErr, const char *Msg = nullptr) { |
726 | if (ValOrErr) |
727 | return std::move(*ValOrErr); |
728 | else { |
729 | if (!Msg) |
730 | Msg = "Failure value returned from cantFail wrapped call"; |
731 | llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 731); |
732 | } |
733 | } |
734 | |
735 | /// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and |
736 | /// returns the contained reference. |
737 | /// |
738 | /// This function can be used to wrap calls to fallible functions ONLY when it |
739 | /// is known that the Error will always be a success value. E.g. |
740 | /// |
741 | /// @code{.cpp} |
742 | /// // foo only attempts the fallible operation if DoFallibleOperation is |
743 | /// // true. If DoFallibleOperation is false then foo always returns a Bar&. |
744 | /// Expected<Bar&> foo(bool DoFallibleOperation); |
745 | /// |
746 | /// Bar &X = cantFail(foo(false)); |
747 | /// @endcode |
748 | template <typename T> |
749 | T& cantFail(Expected<T&> ValOrErr, const char *Msg = nullptr) { |
750 | if (ValOrErr) |
751 | return *ValOrErr; |
752 | else { |
753 | if (!Msg) |
754 | Msg = "Failure value returned from cantFail wrapped call"; |
755 | llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 755); |
756 | } |
757 | } |
758 | |
759 | /// Helper for testing applicability of, and applying, handlers for |
760 | /// ErrorInfo types. |
761 | template <typename HandlerT> |
762 | class ErrorHandlerTraits |
763 | : public ErrorHandlerTraits<decltype( |
764 | &std::remove_reference<HandlerT>::type::operator())> {}; |
765 | |
766 | // Specialization functions of the form 'Error (const ErrT&)'. |
767 | template <typename ErrT> class ErrorHandlerTraits<Error (&)(ErrT &)> { |
768 | public: |
769 | static bool appliesTo(const ErrorInfoBase &E) { |
770 | return E.template isA<ErrT>(); |
771 | } |
772 | |
773 | template <typename HandlerT> |
774 | static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) { |
775 | assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast <void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 775, __PRETTY_FUNCTION__)); |
776 | return H(static_cast<ErrT &>(*E)); |
777 | } |
778 | }; |
779 | |
780 | // Specialization functions of the form 'void (const ErrT&)'. |
781 | template <typename ErrT> class ErrorHandlerTraits<void (&)(ErrT &)> { |
782 | public: |
783 | static bool appliesTo(const ErrorInfoBase &E) { |
784 | return E.template isA<ErrT>(); |
785 | } |
786 | |
787 | template <typename HandlerT> |
788 | static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) { |
789 | assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast <void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 789, __PRETTY_FUNCTION__)); |
790 | H(static_cast<ErrT &>(*E)); |
791 | return Error::success(); |
792 | } |
793 | }; |
794 | |
795 | /// Specialization for functions of the form 'Error (std::unique_ptr<ErrT>)'. |
796 | template <typename ErrT> |
797 | class ErrorHandlerTraits<Error (&)(std::unique_ptr<ErrT>)> { |
798 | public: |
799 | static bool appliesTo(const ErrorInfoBase &E) { |
800 | return E.template isA<ErrT>(); |
801 | } |
802 | |
803 | template <typename HandlerT> |
804 | static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) { |
805 | assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast <void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 805, __PRETTY_FUNCTION__)); |
806 | std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release())); |
807 | return H(std::move(SubE)); |
808 | } |
809 | }; |
810 | |
811 | /// Specialization for functions of the form 'void (std::unique_ptr<ErrT>)'. |
812 | template <typename ErrT> |
813 | class ErrorHandlerTraits<void (&)(std::unique_ptr<ErrT>)> { |
814 | public: |
815 | static bool appliesTo(const ErrorInfoBase &E) { |
816 | return E.template isA<ErrT>(); |
817 | } |
818 | |
819 | template <typename HandlerT> |
820 | static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) { |
821 | assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast <void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 821, __PRETTY_FUNCTION__)); |
822 | std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release())); |
823 | H(std::move(SubE)); |
824 | return Error::success(); |
825 | } |
826 | }; |
827 | |
828 | // Specialization for member functions of the form 'RetT (const ErrT&)'. |
829 | template <typename C, typename RetT, typename ErrT> |
830 | class ErrorHandlerTraits<RetT (C::*)(ErrT &)> |
831 | : public ErrorHandlerTraits<RetT (&)(ErrT &)> {}; |
832 | |
833 | // Specialization for member functions of the form 'RetT (const ErrT&) const'. |
834 | template <typename C, typename RetT, typename ErrT> |
835 | class ErrorHandlerTraits<RetT (C::*)(ErrT &) const> |
836 | : public ErrorHandlerTraits<RetT (&)(ErrT &)> {}; |
837 | |
838 | // Specialization for member functions of the form 'RetT (const ErrT&)'. |
839 | template <typename C, typename RetT, typename ErrT> |
840 | class ErrorHandlerTraits<RetT (C::*)(const ErrT &)> |
841 | : public ErrorHandlerTraits<RetT (&)(ErrT &)> {}; |
842 | |
843 | // Specialization for member functions of the form 'RetT (const ErrT&) const'. |
844 | template <typename C, typename RetT, typename ErrT> |
845 | class ErrorHandlerTraits<RetT (C::*)(const ErrT &) const> |
846 | : public ErrorHandlerTraits<RetT (&)(ErrT &)> {}; |
847 | |
848 | /// Specialization for member functions of the form |
849 | /// 'RetT (std::unique_ptr<ErrT>)'. |
850 | template <typename C, typename RetT, typename ErrT> |
851 | class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>)> |
852 | : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {}; |
853 | |
854 | /// Specialization for member functions of the form |
855 | /// 'RetT (std::unique_ptr<ErrT>) const'. |
856 | template <typename C, typename RetT, typename ErrT> |
857 | class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>) const> |
858 | : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {}; |
859 | |
860 | inline Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload) { |
861 | return Error(std::move(Payload)); |
862 | } |
863 | |
864 | template <typename HandlerT, typename... HandlerTs> |
865 | Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload, |
866 | HandlerT &&Handler, HandlerTs &&... Handlers) { |
867 | if (ErrorHandlerTraits<HandlerT>::appliesTo(*Payload)) |
868 | return ErrorHandlerTraits<HandlerT>::apply(std::forward<HandlerT>(Handler), |
869 | std::move(Payload)); |
870 | return handleErrorImpl(std::move(Payload), |
871 | std::forward<HandlerTs>(Handlers)...); |
872 | } |
873 | |
874 | /// Pass the ErrorInfo(s) contained in E to their respective handlers. Any |
875 | /// unhandled errors (or Errors returned by handlers) are re-concatenated and |
876 | /// returned. |
877 | /// Because this function returns an error, its result must also be checked |
878 | /// or returned. If you intend to handle all errors use handleAllErrors |
879 | /// (which returns void, and will abort() on unhandled errors) instead. |
880 | template <typename... HandlerTs> |
881 | Error handleErrors(Error E, HandlerTs &&... Hs) { |
882 | if (!E) |
883 | return Error::success(); |
884 | |
885 | std::unique_ptr<ErrorInfoBase> Payload = E.takePayload(); |
886 | |
887 | if (Payload->isA<ErrorList>()) { |
888 | ErrorList &List = static_cast<ErrorList &>(*Payload); |
889 | Error R; |
890 | for (auto &P : List.Payloads) |
891 | R = ErrorList::join( |
892 | std::move(R), |
893 | handleErrorImpl(std::move(P), std::forward<HandlerTs>(Hs)...)); |
894 | return R; |
895 | } |
896 | |
897 | return handleErrorImpl(std::move(Payload), std::forward<HandlerTs>(Hs)...); |
898 | } |
899 | |
900 | /// Behaves the same as handleErrors, except that by contract all errors |
901 | /// *must* be handled by the given handlers (i.e. there must be no remaining |
902 | /// errors after running the handlers, or llvm_unreachable is called). |
903 | template <typename... HandlerTs> |
904 | void handleAllErrors(Error E, HandlerTs &&... Handlers) { |
905 | cantFail(handleErrors(std::move(E), std::forward<HandlerTs>(Handlers)...)); |
906 | } |
907 | |
908 | /// Check that E is a non-error, then drop it. |
909 | /// If E is an error, llvm_unreachable will be called. |
910 | inline void handleAllErrors(Error E) { |
911 | cantFail(std::move(E)); |
912 | } |
913 | |
914 | /// Handle any errors (if present) in an Expected<T>, then try a recovery path. |
915 | /// |
916 | /// If the incoming value is a success value it is returned unmodified. If it |
917 | /// is a failure value then it the contained error is passed to handleErrors. |
918 | /// If handleErrors is able to handle the error then the RecoveryPath functor |
919 | /// is called to supply the final result. If handleErrors is not able to |
920 | /// handle all errors then the unhandled errors are returned. |
921 | /// |
922 | /// This utility enables the follow pattern: |
923 | /// |
924 | /// @code{.cpp} |
925 | /// enum FooStrategy { Aggressive, Conservative }; |
926 | /// Expected<Foo> foo(FooStrategy S); |
927 | /// |
928 | /// auto ResultOrErr = |
929 | /// handleExpected( |
930 | /// foo(Aggressive), |
931 | /// []() { return foo(Conservative); }, |
932 | /// [](AggressiveStrategyError&) { |
933 | /// // Implicitly conusme this - we'll recover by using a conservative |
934 | /// // strategy. |
935 | /// }); |
936 | /// |
937 | /// @endcode |
938 | template <typename T, typename RecoveryFtor, typename... HandlerTs> |
939 | Expected<T> handleExpected(Expected<T> ValOrErr, RecoveryFtor &&RecoveryPath, |
940 | HandlerTs &&... Handlers) { |
941 | if (ValOrErr) |
942 | return ValOrErr; |
943 | |
944 | if (auto Err = handleErrors(ValOrErr.takeError(), |
945 | std::forward<HandlerTs>(Handlers)...)) |
946 | return std::move(Err); |
947 | |
948 | return RecoveryPath(); |
949 | } |
950 | |
951 | /// Log all errors (if any) in E to OS. If there are any errors, ErrorBanner |
952 | /// will be printed before the first one is logged. A newline will be printed |
953 | /// after each error. |
954 | /// |
955 | /// This function is compatible with the helpers from Support/WithColor.h. You |
956 | /// can pass any of them as the OS. Please consider using them instead of |
957 | /// including 'error: ' in the ErrorBanner. |
958 | /// |
959 | /// This is useful in the base level of your program to allow clean termination |
960 | /// (allowing clean deallocation of resources, etc.), while reporting error |
961 | /// information to the user. |
962 | void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner = {}); |
963 | |
964 | /// Write all error messages (if any) in E to a string. The newline character |
965 | /// is used to separate error messages. |
966 | inline std::string toString(Error E) { |
967 | SmallVector<std::string, 2> Errors; |
968 | handleAllErrors(std::move(E), [&Errors](const ErrorInfoBase &EI) { |
969 | Errors.push_back(EI.message()); |
970 | }); |
971 | return join(Errors.begin(), Errors.end(), "\n"); |
972 | } |
973 | |
974 | /// Consume a Error without doing anything. This method should be used |
975 | /// only where an error can be considered a reasonable and expected return |
976 | /// value. |
977 | /// |
978 | /// Uses of this method are potentially indicative of design problems: If it's |
979 | /// legitimate to do nothing while processing an "error", the error-producer |
980 | /// might be more clearly refactored to return an Optional<T>. |
981 | inline void consumeError(Error Err) { |
982 | handleAllErrors(std::move(Err), [](const ErrorInfoBase &) {}); |
983 | } |
984 | |
985 | /// Helper for converting an Error to a bool. |
986 | /// |
987 | /// This method returns true if Err is in an error state, or false if it is |
988 | /// in a success state. Puts Err in a checked state in both cases (unlike |
989 | /// Error::operator bool(), which only does this for success states). |
990 | inline bool errorToBool(Error Err) { |
991 | bool IsError = static_cast<bool>(Err); |
992 | if (IsError) |
993 | consumeError(std::move(Err)); |
994 | return IsError; |
995 | } |
996 | |
997 | /// Helper for Errors used as out-parameters. |
998 | /// |
999 | /// This helper is for use with the Error-as-out-parameter idiom, where an error |
1000 | /// is passed to a function or method by reference, rather than being returned. |
1001 | /// In such cases it is helpful to set the checked bit on entry to the function |
1002 | /// so that the error can be written to (unchecked Errors abort on assignment) |
1003 | /// and clear the checked bit on exit so that clients cannot accidentally forget |
1004 | /// to check the result. This helper performs these actions automatically using |
1005 | /// RAII: |
1006 | /// |
1007 | /// @code{.cpp} |
1008 | /// Result foo(Error &Err) { |
1009 | /// ErrorAsOutParameter ErrAsOutParam(&Err); // 'Checked' flag set |
1010 | /// // <body of foo> |
1011 | /// // <- 'Checked' flag auto-cleared when ErrAsOutParam is destructed. |
1012 | /// } |
1013 | /// @endcode |
1014 | /// |
1015 | /// ErrorAsOutParameter takes an Error* rather than Error& so that it can be |
1016 | /// used with optional Errors (Error pointers that are allowed to be null). If |
1017 | /// ErrorAsOutParameter took an Error reference, an instance would have to be |
1018 | /// created inside every condition that verified that Error was non-null. By |
1019 | /// taking an Error pointer we can just create one instance at the top of the |
1020 | /// function. |
1021 | class ErrorAsOutParameter { |
1022 | public: |
1023 | ErrorAsOutParameter(Error *Err) : Err(Err) { |
1024 | // Raise the checked bit if Err is success. |
1025 | if (Err) |
1026 | (void)!!*Err; |
1027 | } |
1028 | |
1029 | ~ErrorAsOutParameter() { |
1030 | // Clear the checked bit. |
1031 | if (Err && !*Err) |
1032 | *Err = Error::success(); |
1033 | } |
1034 | |
1035 | private: |
1036 | Error *Err; |
1037 | }; |
1038 | |
1039 | /// Helper for Expected<T>s used as out-parameters. |
1040 | /// |
1041 | /// See ErrorAsOutParameter. |
1042 | template <typename T> |
1043 | class ExpectedAsOutParameter { |
1044 | public: |
1045 | ExpectedAsOutParameter(Expected<T> *ValOrErr) |
1046 | : ValOrErr(ValOrErr) { |
1047 | if (ValOrErr) |
1048 | (void)!!*ValOrErr; |
1049 | } |
1050 | |
1051 | ~ExpectedAsOutParameter() { |
1052 | if (ValOrErr) |
1053 | ValOrErr->setUnchecked(); |
1054 | } |
1055 | |
1056 | private: |
1057 | Expected<T> *ValOrErr; |
1058 | }; |
1059 | |
1060 | /// This class wraps a std::error_code in a Error. |
1061 | /// |
1062 | /// This is useful if you're writing an interface that returns a Error |
1063 | /// (or Expected) and you want to call code that still returns |
1064 | /// std::error_codes. |
1065 | class ECError : public ErrorInfo<ECError> { |
1066 | friend Error errorCodeToError(std::error_code); |
1067 | |
1068 | virtual void anchor() override; |
1069 | |
1070 | public: |
1071 | void setErrorCode(std::error_code EC) { this->EC = EC; } |
1072 | std::error_code convertToErrorCode() const override { return EC; } |
1073 | void log(raw_ostream &OS) const override { OS << EC.message(); } |
1074 | |
1075 | // Used by ErrorInfo::classID. |
1076 | static char ID; |
1077 | |
1078 | protected: |
1079 | ECError() = default; |
1080 | ECError(std::error_code EC) : EC(EC) {} |
1081 | |
1082 | std::error_code EC; |
1083 | }; |
1084 | |
1085 | /// The value returned by this function can be returned from convertToErrorCode |
1086 | /// for Error values where no sensible translation to std::error_code exists. |
1087 | /// It should only be used in this situation, and should never be used where a |
1088 | /// sensible conversion to std::error_code is available, as attempts to convert |
1089 | /// to/from this error will result in a fatal error. (i.e. it is a programmatic |
1090 | ///error to try to convert such a value). |
1091 | std::error_code inconvertibleErrorCode(); |
1092 | |
1093 | /// Helper for converting an std::error_code to a Error. |
1094 | Error errorCodeToError(std::error_code EC); |
1095 | |
1096 | /// Helper for converting an ECError to a std::error_code. |
1097 | /// |
1098 | /// This method requires that Err be Error() or an ECError, otherwise it |
1099 | /// will trigger a call to abort(). |
1100 | std::error_code errorToErrorCode(Error Err); |
1101 | |
1102 | /// Convert an ErrorOr<T> to an Expected<T>. |
1103 | template <typename T> Expected<T> errorOrToExpected(ErrorOr<T> &&EO) { |
1104 | if (auto EC = EO.getError()) |
1105 | return errorCodeToError(EC); |
1106 | return std::move(*EO); |
1107 | } |
1108 | |
1109 | /// Convert an Expected<T> to an ErrorOr<T>. |
1110 | template <typename T> ErrorOr<T> expectedToErrorOr(Expected<T> &&E) { |
1111 | if (auto Err = E.takeError()) |
1112 | return errorToErrorCode(std::move(Err)); |
1113 | return std::move(*E); |
1114 | } |
1115 | |
1116 | /// This class wraps a string in an Error. |
1117 | /// |
1118 | /// StringError is useful in cases where the client is not expected to be able |
1119 | /// to consume the specific error message programmatically (for example, if the |
1120 | /// error message is to be presented to the user). |
1121 | /// |
1122 | /// StringError can also be used when additional information is to be printed |
1123 | /// along with a error_code message. Depending on the constructor called, this |
1124 | /// class can either display: |
1125 | /// 1. the error_code message (ECError behavior) |
1126 | /// 2. a string |
1127 | /// 3. the error_code message and a string |
1128 | /// |
1129 | /// These behaviors are useful when subtyping is required; for example, when a |
1130 | /// specific library needs an explicit error type. In the example below, |
1131 | /// PDBError is derived from StringError: |
1132 | /// |
1133 | /// @code{.cpp} |
1134 | /// Expected<int> foo() { |
1135 | /// return llvm::make_error<PDBError>(pdb_error_code::dia_failed_loading, |
1136 | /// "Additional information"); |
1137 | /// } |
1138 | /// @endcode |
1139 | /// |
1140 | class StringError : public ErrorInfo<StringError> { |
1141 | public: |
1142 | static char ID; |
1143 | |
1144 | // Prints EC + S and converts to EC |
1145 | StringError(std::error_code EC, const Twine &S = Twine()); |
1146 | |
1147 | // Prints S and converts to EC |
1148 | StringError(const Twine &S, std::error_code EC); |
1149 | |
1150 | void log(raw_ostream &OS) const override; |
1151 | std::error_code convertToErrorCode() const override; |
1152 | |
1153 | const std::string &getMessage() const { return Msg; } |
1154 | |
1155 | private: |
1156 | std::string Msg; |
1157 | std::error_code EC; |
1158 | const bool PrintMsgOnly = false; |
1159 | }; |
1160 | |
1161 | /// Create formatted StringError object. |
1162 | template <typename... Ts> |
1163 | Error createStringError(std::error_code EC, char const *Fmt, |
1164 | const Ts &... Vals) { |
1165 | std::string Buffer; |
1166 | raw_string_ostream Stream(Buffer); |
1167 | Stream << format(Fmt, Vals...); |
1168 | return make_error<StringError>(Stream.str(), EC); |
1169 | } |
1170 | |
1171 | Error createStringError(std::error_code EC, char const *Msg); |
1172 | |
1173 | /// This class wraps a filename and another Error. |
1174 | /// |
1175 | /// In some cases, an error needs to live along a 'source' name, in order to |
1176 | /// show more detailed information to the user. |
1177 | class FileError final : public ErrorInfo<FileError> { |
1178 | |
1179 | friend Error createFileError(const Twine &, Error); |
1180 | friend Error createFileError(const Twine &, size_t, Error); |
1181 | |
1182 | public: |
1183 | void log(raw_ostream &OS) const override { |
1184 | assert(Err && !FileName.empty() && "Trying to log after takeError().")((Err && !FileName.empty() && "Trying to log after takeError()." ) ? static_cast<void> (0) : __assert_fail ("Err && !FileName.empty() && \"Trying to log after takeError().\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 1184, __PRETTY_FUNCTION__)); |
1185 | OS << "'" << FileName << "': "; |
1186 | if (Line.hasValue()) |
1187 | OS << "line " << Line.getValue() << ": "; |
1188 | Err->log(OS); |
1189 | } |
1190 | |
1191 | Error takeError() { return Error(std::move(Err)); } |
1192 | |
1193 | std::error_code convertToErrorCode() const override; |
1194 | |
1195 | // Used by ErrorInfo::classID. |
1196 | static char ID; |
1197 | |
1198 | private: |
1199 | FileError(const Twine &F, Optional<size_t> LineNum, |
1200 | std::unique_ptr<ErrorInfoBase> E) { |
1201 | assert(E && "Cannot create FileError from Error success value.")((E && "Cannot create FileError from Error success value." ) ? static_cast<void> (0) : __assert_fail ("E && \"Cannot create FileError from Error success value.\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 1201, __PRETTY_FUNCTION__)); |
1202 | assert(!F.isTriviallyEmpty() &&((!F.isTriviallyEmpty() && "The file name provided to FileError must not be empty." ) ? static_cast<void> (0) : __assert_fail ("!F.isTriviallyEmpty() && \"The file name provided to FileError must not be empty.\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 1203, __PRETTY_FUNCTION__)) |
1203 | "The file name provided to FileError must not be empty.")((!F.isTriviallyEmpty() && "The file name provided to FileError must not be empty." ) ? static_cast<void> (0) : __assert_fail ("!F.isTriviallyEmpty() && \"The file name provided to FileError must not be empty.\"" , "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h" , 1203, __PRETTY_FUNCTION__)); |
1204 | FileName = F.str(); |
1205 | Err = std::move(E); |
1206 | Line = std::move(LineNum); |
1207 | } |
1208 | |
1209 | static Error build(const Twine &F, Optional<size_t> Line, Error E) { |
1210 | return Error( |
1211 | std::unique_ptr<FileError>(new FileError(F, Line, E.takePayload()))); |
1212 | } |
1213 | |
1214 | std::string FileName; |
1215 | Optional<size_t> Line; |
1216 | std::unique_ptr<ErrorInfoBase> Err; |
1217 | }; |
1218 | |
1219 | /// Concatenate a source file path and/or name with an Error. The resulting |
1220 | /// Error is unchecked. |
1221 | inline Error createFileError(const Twine &F, Error E) { |
1222 | return FileError::build(F, Optional<size_t>(), std::move(E)); |
1223 | } |
1224 | |
1225 | /// Concatenate a source file path and/or name with line number and an Error. |
1226 | /// The resulting Error is unchecked. |
1227 | inline Error createFileError(const Twine &F, size_t Line, Error E) { |
1228 | return FileError::build(F, Optional<size_t>(Line), std::move(E)); |
1229 | } |
1230 | |
1231 | /// Concatenate a source file path and/or name with a std::error_code |
1232 | /// to form an Error object. |
1233 | inline Error createFileError(const Twine &F, std::error_code EC) { |
1234 | return createFileError(F, errorCodeToError(EC)); |
1235 | } |
1236 | |
1237 | /// Concatenate a source file path and/or name with line number and |
1238 | /// std::error_code to form an Error object. |
1239 | inline Error createFileError(const Twine &F, size_t Line, std::error_code EC) { |
1240 | return createFileError(F, Line, errorCodeToError(EC)); |
1241 | } |
1242 | |
1243 | Error createFileError(const Twine &F, ErrorSuccess) = delete; |
1244 | |
1245 | /// Helper for check-and-exit error handling. |
1246 | /// |
1247 | /// For tool use only. NOT FOR USE IN LIBRARY CODE. |
1248 | /// |
1249 | class ExitOnError { |
1250 | public: |
1251 | /// Create an error on exit helper. |
1252 | ExitOnError(std::string Banner = "", int DefaultErrorExitCode = 1) |
1253 | : Banner(std::move(Banner)), |
1254 | GetExitCode([=](const Error &) { return DefaultErrorExitCode; }) {} |
1255 | |
1256 | /// Set the banner string for any errors caught by operator(). |
1257 | void setBanner(std::string Banner) { this->Banner = std::move(Banner); } |
1258 | |
1259 | /// Set the exit-code mapper function. |
1260 | void setExitCodeMapper(std::function<int(const Error &)> GetExitCode) { |
1261 | this->GetExitCode = std::move(GetExitCode); |
1262 | } |
1263 | |
1264 | /// Check Err. If it's in a failure state log the error(s) and exit. |
1265 | void operator()(Error Err) const { checkError(std::move(Err)); } |
1266 | |
1267 | /// Check E. If it's in a success state then return the contained value. If |
1268 | /// it's in a failure state log the error(s) and exit. |
1269 | template <typename T> T operator()(Expected<T> &&E) const { |
1270 | checkError(E.takeError()); |
1271 | return std::move(*E); |
1272 | } |
1273 | |
1274 | /// Check E. If it's in a success state then return the contained reference. If |
1275 | /// it's in a failure state log the error(s) and exit. |
1276 | template <typename T> T& operator()(Expected<T&> &&E) const { |
1277 | checkError(E.takeError()); |
1278 | return *E; |
1279 | } |
1280 | |
1281 | private: |
1282 | void checkError(Error Err) const { |
1283 | if (Err) { |
1284 | int ExitCode = GetExitCode(Err); |
1285 | logAllUnhandledErrors(std::move(Err), errs(), Banner); |
1286 | exit(ExitCode); |
1287 | } |
1288 | } |
1289 | |
1290 | std::string Banner; |
1291 | std::function<int(const Error &)> GetExitCode; |
1292 | }; |
1293 | |
1294 | /// Conversion from Error to LLVMErrorRef for C error bindings. |
1295 | inline LLVMErrorRef wrap(Error Err) { |
1296 | return reinterpret_cast<LLVMErrorRef>(Err.takePayload().release()); |
1297 | } |
1298 | |
1299 | /// Conversion from LLVMErrorRef to Error for C error bindings. |
1300 | inline Error unwrap(LLVMErrorRef ErrRef) { |
1301 | return Error(std::unique_ptr<ErrorInfoBase>( |
1302 | reinterpret_cast<ErrorInfoBase *>(ErrRef))); |
1303 | } |
1304 | |
1305 | } // end namespace llvm |
1306 | |
1307 | #endif // LLVM_SUPPORT_ERROR_H |