File: | llvm/include/llvm/Support/Error.h |
Warning: | line 740, column 7 Value stored to 'Msg' is never read |
Press '?' to see keyboard shortcuts
Keyboard shortcuts:
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 | // ErrorList needs to be able to yank ErrorInfoBase pointers out of Errors |
159 | // to add to the error list. It can't rely on handleErrors for this, since |
160 | // handleErrors does not support ErrorList handlers. |
161 | friend class ErrorList; |
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_CHECKS0 |
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 | [[noreturn]] void fatalUncheckedError() const; |
261 | #endif |
262 | |
263 | void assertIsChecked() { |
264 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
265 | if (LLVM_UNLIKELY(!getChecked() || getPtr())__builtin_expect((bool)(!getChecked() || getPtr()), false)) |
266 | fatalUncheckedError(); |
267 | #endif |
268 | } |
269 | |
270 | ErrorInfoBase *getPtr() const { |
271 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
272 | return reinterpret_cast<ErrorInfoBase*>( |
273 | reinterpret_cast<uintptr_t>(Payload) & |
274 | ~static_cast<uintptr_t>(0x1)); |
275 | #else |
276 | return Payload; |
277 | #endif |
278 | } |
279 | |
280 | void setPtr(ErrorInfoBase *EI) { |
281 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
282 | Payload = reinterpret_cast<ErrorInfoBase*>( |
283 | (reinterpret_cast<uintptr_t>(EI) & |
284 | ~static_cast<uintptr_t>(0x1)) | |
285 | (reinterpret_cast<uintptr_t>(Payload) & 0x1)); |
286 | #else |
287 | Payload = EI; |
288 | #endif |
289 | } |
290 | |
291 | bool getChecked() const { |
292 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
293 | return (reinterpret_cast<uintptr_t>(Payload) & 0x1) == 0; |
294 | #else |
295 | return true; |
296 | #endif |
297 | } |
298 | |
299 | void setChecked(bool V) { |
300 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
301 | Payload = reinterpret_cast<ErrorInfoBase*>( |
302 | (reinterpret_cast<uintptr_t>(Payload) & |
303 | ~static_cast<uintptr_t>(0x1)) | |
304 | (V ? 0 : 1)); |
305 | #endif |
306 | } |
307 | |
308 | std::unique_ptr<ErrorInfoBase> takePayload() { |
309 | std::unique_ptr<ErrorInfoBase> Tmp(getPtr()); |
310 | setPtr(nullptr); |
311 | setChecked(true); |
312 | return Tmp; |
313 | } |
314 | |
315 | friend raw_ostream &operator<<(raw_ostream &OS, const Error &E) { |
316 | if (auto P = E.getPtr()) |
317 | P->log(OS); |
318 | else |
319 | OS << "success"; |
320 | return OS; |
321 | } |
322 | |
323 | ErrorInfoBase *Payload = nullptr; |
324 | }; |
325 | |
326 | /// Subclass of Error for the sole purpose of identifying the success path in |
327 | /// the type system. This allows to catch invalid conversion to Expected<T> at |
328 | /// compile time. |
329 | class ErrorSuccess final : public Error {}; |
330 | |
331 | inline ErrorSuccess Error::success() { return ErrorSuccess(); } |
332 | |
333 | /// Make a Error instance representing failure using the given error info |
334 | /// type. |
335 | template <typename ErrT, typename... ArgTs> Error make_error(ArgTs &&... Args) { |
336 | return Error(std::make_unique<ErrT>(std::forward<ArgTs>(Args)...)); |
337 | } |
338 | |
339 | /// Base class for user error types. Users should declare their error types |
340 | /// like: |
341 | /// |
342 | /// class MyError : public ErrorInfo<MyError> { |
343 | /// .... |
344 | /// }; |
345 | /// |
346 | /// This class provides an implementation of the ErrorInfoBase::kind |
347 | /// method, which is used by the Error RTTI system. |
348 | template <typename ThisErrT, typename ParentErrT = ErrorInfoBase> |
349 | class ErrorInfo : public ParentErrT { |
350 | public: |
351 | using ParentErrT::ParentErrT; // inherit constructors |
352 | |
353 | static const void *classID() { return &ThisErrT::ID; } |
354 | |
355 | const void *dynamicClassID() const override { return &ThisErrT::ID; } |
356 | |
357 | bool isA(const void *const ClassID) const override { |
358 | return ClassID == classID() || ParentErrT::isA(ClassID); |
359 | } |
360 | }; |
361 | |
362 | /// Special ErrorInfo subclass representing a list of ErrorInfos. |
363 | /// Instances of this class are constructed by joinError. |
364 | class ErrorList final : public ErrorInfo<ErrorList> { |
365 | // handleErrors needs to be able to iterate the payload list of an |
366 | // ErrorList. |
367 | template <typename... HandlerTs> |
368 | friend Error handleErrors(Error E, HandlerTs &&... Handlers); |
369 | |
370 | // joinErrors is implemented in terms of join. |
371 | friend Error joinErrors(Error, Error); |
372 | |
373 | public: |
374 | void log(raw_ostream &OS) const override { |
375 | OS << "Multiple errors:\n"; |
376 | for (auto &ErrPayload : Payloads) { |
377 | ErrPayload->log(OS); |
378 | OS << "\n"; |
379 | } |
380 | } |
381 | |
382 | std::error_code convertToErrorCode() const override; |
383 | |
384 | // Used by ErrorInfo::classID. |
385 | static char ID; |
386 | |
387 | private: |
388 | ErrorList(std::unique_ptr<ErrorInfoBase> Payload1, |
389 | std::unique_ptr<ErrorInfoBase> Payload2) { |
390 | assert(!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() &&(static_cast<void> (0)) |
391 | "ErrorList constructor payloads should be singleton errors")(static_cast<void> (0)); |
392 | Payloads.push_back(std::move(Payload1)); |
393 | Payloads.push_back(std::move(Payload2)); |
394 | } |
395 | |
396 | static Error join(Error E1, Error E2) { |
397 | if (!E1) |
398 | return E2; |
399 | if (!E2) |
400 | return E1; |
401 | if (E1.isA<ErrorList>()) { |
402 | auto &E1List = static_cast<ErrorList &>(*E1.getPtr()); |
403 | if (E2.isA<ErrorList>()) { |
404 | auto E2Payload = E2.takePayload(); |
405 | auto &E2List = static_cast<ErrorList &>(*E2Payload); |
406 | for (auto &Payload : E2List.Payloads) |
407 | E1List.Payloads.push_back(std::move(Payload)); |
408 | } else |
409 | E1List.Payloads.push_back(E2.takePayload()); |
410 | |
411 | return E1; |
412 | } |
413 | if (E2.isA<ErrorList>()) { |
414 | auto &E2List = static_cast<ErrorList &>(*E2.getPtr()); |
415 | E2List.Payloads.insert(E2List.Payloads.begin(), E1.takePayload()); |
416 | return E2; |
417 | } |
418 | return Error(std::unique_ptr<ErrorList>( |
419 | new ErrorList(E1.takePayload(), E2.takePayload()))); |
420 | } |
421 | |
422 | std::vector<std::unique_ptr<ErrorInfoBase>> Payloads; |
423 | }; |
424 | |
425 | /// Concatenate errors. The resulting Error is unchecked, and contains the |
426 | /// ErrorInfo(s), if any, contained in E1, followed by the |
427 | /// ErrorInfo(s), if any, contained in E2. |
428 | inline Error joinErrors(Error E1, Error E2) { |
429 | return ErrorList::join(std::move(E1), std::move(E2)); |
430 | } |
431 | |
432 | /// Tagged union holding either a T or a Error. |
433 | /// |
434 | /// This class parallels ErrorOr, but replaces error_code with Error. Since |
435 | /// Error cannot be copied, this class replaces getError() with |
436 | /// takeError(). It also adds an bool errorIsA<ErrT>() method for testing the |
437 | /// error class type. |
438 | /// |
439 | /// Example usage of 'Expected<T>' as a function return type: |
440 | /// |
441 | /// @code{.cpp} |
442 | /// Expected<int> myDivide(int A, int B) { |
443 | /// if (B == 0) { |
444 | /// // return an Error |
445 | /// return createStringError(inconvertibleErrorCode(), |
446 | /// "B must not be zero!"); |
447 | /// } |
448 | /// // return an integer |
449 | /// return A / B; |
450 | /// } |
451 | /// @endcode |
452 | /// |
453 | /// Checking the results of to a function returning 'Expected<T>': |
454 | /// @code{.cpp} |
455 | /// if (auto E = Result.takeError()) { |
456 | /// // We must consume the error. Typically one of: |
457 | /// // - return the error to our caller |
458 | /// // - toString(), when logging |
459 | /// // - consumeError(), to silently swallow the error |
460 | /// // - handleErrors(), to distinguish error types |
461 | /// errs() << "Problem with division " << toString(std::move(E)) << "\n"; |
462 | /// return; |
463 | /// } |
464 | /// // use the result |
465 | /// outs() << "The answer is " << *Result << "\n"; |
466 | /// @endcode |
467 | /// |
468 | /// For unit-testing a function returning an 'Expceted<T>', see the |
469 | /// 'EXPECT_THAT_EXPECTED' macros in llvm/Testing/Support/Error.h |
470 | |
471 | template <class T> class LLVM_NODISCARD[[clang::warn_unused_result]] Expected { |
472 | template <class T1> friend class ExpectedAsOutParameter; |
473 | template <class OtherT> friend class Expected; |
474 | |
475 | static constexpr bool isRef = std::is_reference<T>::value; |
476 | |
477 | using wrap = std::reference_wrapper<std::remove_reference_t<T>>; |
478 | |
479 | using error_type = std::unique_ptr<ErrorInfoBase>; |
480 | |
481 | public: |
482 | using storage_type = std::conditional_t<isRef, wrap, T>; |
483 | using value_type = T; |
484 | |
485 | private: |
486 | using reference = std::remove_reference_t<T> &; |
487 | using const_reference = const std::remove_reference_t<T> &; |
488 | using pointer = std::remove_reference_t<T> *; |
489 | using const_pointer = const std::remove_reference_t<T> *; |
490 | |
491 | public: |
492 | /// Create an Expected<T> error value from the given Error. |
493 | Expected(Error Err) |
494 | : HasError(true) |
495 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
496 | // Expected is unchecked upon construction in Debug builds. |
497 | , Unchecked(true) |
498 | #endif |
499 | { |
500 | assert(Err && "Cannot create Expected<T> from Error success value.")(static_cast<void> (0)); |
501 | new (getErrorStorage()) error_type(Err.takePayload()); |
502 | } |
503 | |
504 | /// Forbid to convert from Error::success() implicitly, this avoids having |
505 | /// Expected<T> foo() { return Error::success(); } which compiles otherwise |
506 | /// but triggers the assertion above. |
507 | Expected(ErrorSuccess) = delete; |
508 | |
509 | /// Create an Expected<T> success value from the given OtherT value, which |
510 | /// must be convertible to T. |
511 | template <typename OtherT> |
512 | Expected(OtherT &&Val, |
513 | std::enable_if_t<std::is_convertible<OtherT, T>::value> * = nullptr) |
514 | : HasError(false) |
515 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
516 | // Expected is unchecked upon construction in Debug builds. |
517 | , |
518 | Unchecked(true) |
519 | #endif |
520 | { |
521 | new (getStorage()) storage_type(std::forward<OtherT>(Val)); |
522 | } |
523 | |
524 | /// Move construct an Expected<T> value. |
525 | Expected(Expected &&Other) { moveConstruct(std::move(Other)); } |
526 | |
527 | /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT |
528 | /// must be convertible to T. |
529 | template <class OtherT> |
530 | Expected( |
531 | Expected<OtherT> &&Other, |
532 | std::enable_if_t<std::is_convertible<OtherT, T>::value> * = nullptr) { |
533 | moveConstruct(std::move(Other)); |
534 | } |
535 | |
536 | /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT |
537 | /// isn't convertible to T. |
538 | template <class OtherT> |
539 | explicit Expected( |
540 | Expected<OtherT> &&Other, |
541 | std::enable_if_t<!std::is_convertible<OtherT, T>::value> * = nullptr) { |
542 | moveConstruct(std::move(Other)); |
543 | } |
544 | |
545 | /// Move-assign from another Expected<T>. |
546 | Expected &operator=(Expected &&Other) { |
547 | moveAssign(std::move(Other)); |
548 | return *this; |
549 | } |
550 | |
551 | /// Destroy an Expected<T>. |
552 | ~Expected() { |
553 | assertIsChecked(); |
554 | if (!HasError) |
555 | getStorage()->~storage_type(); |
556 | else |
557 | getErrorStorage()->~error_type(); |
558 | } |
559 | |
560 | /// Return false if there is an error. |
561 | explicit operator bool() { |
562 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
563 | Unchecked = HasError; |
564 | #endif |
565 | return !HasError; |
566 | } |
567 | |
568 | /// Returns a reference to the stored T value. |
569 | reference get() { |
570 | assertIsChecked(); |
571 | return *getStorage(); |
572 | } |
573 | |
574 | /// Returns a const reference to the stored T value. |
575 | const_reference get() const { |
576 | assertIsChecked(); |
577 | return const_cast<Expected<T> *>(this)->get(); |
578 | } |
579 | |
580 | /// Check that this Expected<T> is an error of type ErrT. |
581 | template <typename ErrT> bool errorIsA() const { |
582 | return HasError && (*getErrorStorage())->template isA<ErrT>(); |
583 | } |
584 | |
585 | /// Take ownership of the stored error. |
586 | /// After calling this the Expected<T> is in an indeterminate state that can |
587 | /// only be safely destructed. No further calls (beside the destructor) should |
588 | /// be made on the Expected<T> value. |
589 | Error takeError() { |
590 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
591 | Unchecked = false; |
592 | #endif |
593 | return HasError ? Error(std::move(*getErrorStorage())) : Error::success(); |
594 | } |
595 | |
596 | /// Returns a pointer to the stored T value. |
597 | pointer operator->() { |
598 | assertIsChecked(); |
599 | return toPointer(getStorage()); |
600 | } |
601 | |
602 | /// Returns a const pointer to the stored T value. |
603 | const_pointer operator->() const { |
604 | assertIsChecked(); |
605 | return toPointer(getStorage()); |
606 | } |
607 | |
608 | /// Returns a reference to the stored T value. |
609 | reference operator*() { |
610 | assertIsChecked(); |
611 | return *getStorage(); |
612 | } |
613 | |
614 | /// Returns a const reference to the stored T value. |
615 | const_reference operator*() const { |
616 | assertIsChecked(); |
617 | return *getStorage(); |
618 | } |
619 | |
620 | private: |
621 | template <class T1> |
622 | static bool compareThisIfSameType(const T1 &a, const T1 &b) { |
623 | return &a == &b; |
624 | } |
625 | |
626 | template <class T1, class T2> |
627 | static bool compareThisIfSameType(const T1 &, const T2 &) { |
628 | return false; |
629 | } |
630 | |
631 | template <class OtherT> void moveConstruct(Expected<OtherT> &&Other) { |
632 | HasError = Other.HasError; |
633 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
634 | Unchecked = true; |
635 | Other.Unchecked = false; |
636 | #endif |
637 | |
638 | if (!HasError) |
639 | new (getStorage()) storage_type(std::move(*Other.getStorage())); |
640 | else |
641 | new (getErrorStorage()) error_type(std::move(*Other.getErrorStorage())); |
642 | } |
643 | |
644 | template <class OtherT> void moveAssign(Expected<OtherT> &&Other) { |
645 | assertIsChecked(); |
646 | |
647 | if (compareThisIfSameType(*this, Other)) |
648 | return; |
649 | |
650 | this->~Expected(); |
651 | new (this) Expected(std::move(Other)); |
652 | } |
653 | |
654 | pointer toPointer(pointer Val) { return Val; } |
655 | |
656 | const_pointer toPointer(const_pointer Val) const { return Val; } |
657 | |
658 | pointer toPointer(wrap *Val) { return &Val->get(); } |
659 | |
660 | const_pointer toPointer(const wrap *Val) const { return &Val->get(); } |
661 | |
662 | storage_type *getStorage() { |
663 | assert(!HasError && "Cannot get value when an error exists!")(static_cast<void> (0)); |
664 | return reinterpret_cast<storage_type *>(&TStorage); |
665 | } |
666 | |
667 | const storage_type *getStorage() const { |
668 | assert(!HasError && "Cannot get value when an error exists!")(static_cast<void> (0)); |
669 | return reinterpret_cast<const storage_type *>(&TStorage); |
670 | } |
671 | |
672 | error_type *getErrorStorage() { |
673 | assert(HasError && "Cannot get error when a value exists!")(static_cast<void> (0)); |
674 | return reinterpret_cast<error_type *>(&ErrorStorage); |
675 | } |
676 | |
677 | const error_type *getErrorStorage() const { |
678 | assert(HasError && "Cannot get error when a value exists!")(static_cast<void> (0)); |
679 | return reinterpret_cast<const error_type *>(&ErrorStorage); |
680 | } |
681 | |
682 | // Used by ExpectedAsOutParameter to reset the checked flag. |
683 | void setUnchecked() { |
684 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
685 | Unchecked = true; |
686 | #endif |
687 | } |
688 | |
689 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
690 | [[noreturn]] LLVM_ATTRIBUTE_NOINLINE__attribute__((noinline)) void fatalUncheckedExpected() const { |
691 | dbgs() << "Expected<T> must be checked before access or destruction.\n"; |
692 | if (HasError) { |
693 | dbgs() << "Unchecked Expected<T> contained error:\n"; |
694 | (*getErrorStorage())->log(dbgs()); |
695 | } else |
696 | dbgs() << "Expected<T> value was in success state. (Note: Expected<T> " |
697 | "values in success mode must still be checked prior to being " |
698 | "destroyed).\n"; |
699 | abort(); |
700 | } |
701 | #endif |
702 | |
703 | void assertIsChecked() const { |
704 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
705 | if (LLVM_UNLIKELY(Unchecked)__builtin_expect((bool)(Unchecked), false)) |
706 | fatalUncheckedExpected(); |
707 | #endif |
708 | } |
709 | |
710 | union { |
711 | AlignedCharArrayUnion<storage_type> TStorage; |
712 | AlignedCharArrayUnion<error_type> ErrorStorage; |
713 | }; |
714 | bool HasError : 1; |
715 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
716 | bool Unchecked : 1; |
717 | #endif |
718 | }; |
719 | |
720 | /// Report a serious error, calling any installed error handler. See |
721 | /// ErrorHandling.h. |
722 | [[noreturn]] void report_fatal_error(Error Err, bool gen_crash_diag = true); |
723 | |
724 | /// Report a fatal error if Err is a failure value. |
725 | /// |
726 | /// This function can be used to wrap calls to fallible functions ONLY when it |
727 | /// is known that the Error will always be a success value. E.g. |
728 | /// |
729 | /// @code{.cpp} |
730 | /// // foo only attempts the fallible operation if DoFallibleOperation is |
731 | /// // true. If DoFallibleOperation is false then foo always returns |
732 | /// // Error::success(). |
733 | /// Error foo(bool DoFallibleOperation); |
734 | /// |
735 | /// cantFail(foo(false)); |
736 | /// @endcode |
737 | inline void cantFail(Error Err, const char *Msg = nullptr) { |
738 | if (Err) { |
739 | if (!Msg) |
740 | Msg = "Failure value returned from cantFail wrapped call"; |
Value stored to 'Msg' is never read | |
741 | #ifndef NDEBUG1 |
742 | std::string Str; |
743 | raw_string_ostream OS(Str); |
744 | OS << Msg << "\n" << Err; |
745 | Msg = OS.str().c_str(); |
746 | #endif |
747 | llvm_unreachable(Msg)__builtin_unreachable(); |
748 | } |
749 | } |
750 | |
751 | /// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and |
752 | /// returns the contained value. |
753 | /// |
754 | /// This function can be used to wrap calls to fallible functions ONLY when it |
755 | /// is known that the Error will always be a success value. E.g. |
756 | /// |
757 | /// @code{.cpp} |
758 | /// // foo only attempts the fallible operation if DoFallibleOperation is |
759 | /// // true. If DoFallibleOperation is false then foo always returns an int. |
760 | /// Expected<int> foo(bool DoFallibleOperation); |
761 | /// |
762 | /// int X = cantFail(foo(false)); |
763 | /// @endcode |
764 | template <typename T> |
765 | T cantFail(Expected<T> ValOrErr, const char *Msg = nullptr) { |
766 | if (ValOrErr) |
767 | return std::move(*ValOrErr); |
768 | else { |
769 | if (!Msg) |
770 | Msg = "Failure value returned from cantFail wrapped call"; |
771 | #ifndef NDEBUG1 |
772 | std::string Str; |
773 | raw_string_ostream OS(Str); |
774 | auto E = ValOrErr.takeError(); |
775 | OS << Msg << "\n" << E; |
776 | Msg = OS.str().c_str(); |
777 | #endif |
778 | llvm_unreachable(Msg)__builtin_unreachable(); |
779 | } |
780 | } |
781 | |
782 | /// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and |
783 | /// returns the contained reference. |
784 | /// |
785 | /// This function can be used to wrap calls to fallible functions ONLY when it |
786 | /// is known that the Error will always be a success value. E.g. |
787 | /// |
788 | /// @code{.cpp} |
789 | /// // foo only attempts the fallible operation if DoFallibleOperation is |
790 | /// // true. If DoFallibleOperation is false then foo always returns a Bar&. |
791 | /// Expected<Bar&> foo(bool DoFallibleOperation); |
792 | /// |
793 | /// Bar &X = cantFail(foo(false)); |
794 | /// @endcode |
795 | template <typename T> |
796 | T& cantFail(Expected<T&> ValOrErr, const char *Msg = nullptr) { |
797 | if (ValOrErr) |
798 | return *ValOrErr; |
799 | else { |
800 | if (!Msg) |
801 | Msg = "Failure value returned from cantFail wrapped call"; |
802 | #ifndef NDEBUG1 |
803 | std::string Str; |
804 | raw_string_ostream OS(Str); |
805 | auto E = ValOrErr.takeError(); |
806 | OS << Msg << "\n" << E; |
807 | Msg = OS.str().c_str(); |
808 | #endif |
809 | llvm_unreachable(Msg)__builtin_unreachable(); |
810 | } |
811 | } |
812 | |
813 | /// Helper for testing applicability of, and applying, handlers for |
814 | /// ErrorInfo types. |
815 | template <typename HandlerT> |
816 | class ErrorHandlerTraits |
817 | : public ErrorHandlerTraits<decltype( |
818 | &std::remove_reference<HandlerT>::type::operator())> {}; |
819 | |
820 | // Specialization functions of the form 'Error (const ErrT&)'. |
821 | template <typename ErrT> class ErrorHandlerTraits<Error (&)(ErrT &)> { |
822 | public: |
823 | static bool appliesTo(const ErrorInfoBase &E) { |
824 | return E.template isA<ErrT>(); |
825 | } |
826 | |
827 | template <typename HandlerT> |
828 | static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) { |
829 | assert(appliesTo(*E) && "Applying incorrect handler")(static_cast<void> (0)); |
830 | return H(static_cast<ErrT &>(*E)); |
831 | } |
832 | }; |
833 | |
834 | // Specialization functions of the form 'void (const ErrT&)'. |
835 | template <typename ErrT> class ErrorHandlerTraits<void (&)(ErrT &)> { |
836 | public: |
837 | static bool appliesTo(const ErrorInfoBase &E) { |
838 | return E.template isA<ErrT>(); |
839 | } |
840 | |
841 | template <typename HandlerT> |
842 | static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) { |
843 | assert(appliesTo(*E) && "Applying incorrect handler")(static_cast<void> (0)); |
844 | H(static_cast<ErrT &>(*E)); |
845 | return Error::success(); |
846 | } |
847 | }; |
848 | |
849 | /// Specialization for functions of the form 'Error (std::unique_ptr<ErrT>)'. |
850 | template <typename ErrT> |
851 | class ErrorHandlerTraits<Error (&)(std::unique_ptr<ErrT>)> { |
852 | public: |
853 | static bool appliesTo(const ErrorInfoBase &E) { |
854 | return E.template isA<ErrT>(); |
855 | } |
856 | |
857 | template <typename HandlerT> |
858 | static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) { |
859 | assert(appliesTo(*E) && "Applying incorrect handler")(static_cast<void> (0)); |
860 | std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release())); |
861 | return H(std::move(SubE)); |
862 | } |
863 | }; |
864 | |
865 | /// Specialization for functions of the form 'void (std::unique_ptr<ErrT>)'. |
866 | template <typename ErrT> |
867 | class ErrorHandlerTraits<void (&)(std::unique_ptr<ErrT>)> { |
868 | public: |
869 | static bool appliesTo(const ErrorInfoBase &E) { |
870 | return E.template isA<ErrT>(); |
871 | } |
872 | |
873 | template <typename HandlerT> |
874 | static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) { |
875 | assert(appliesTo(*E) && "Applying incorrect handler")(static_cast<void> (0)); |
876 | std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release())); |
877 | H(std::move(SubE)); |
878 | return Error::success(); |
879 | } |
880 | }; |
881 | |
882 | // Specialization for member functions of the form 'RetT (const ErrT&)'. |
883 | template <typename C, typename RetT, typename ErrT> |
884 | class ErrorHandlerTraits<RetT (C::*)(ErrT &)> |
885 | : public ErrorHandlerTraits<RetT (&)(ErrT &)> {}; |
886 | |
887 | // Specialization for member functions of the form 'RetT (const ErrT&) const'. |
888 | template <typename C, typename RetT, typename ErrT> |
889 | class ErrorHandlerTraits<RetT (C::*)(ErrT &) const> |
890 | : public ErrorHandlerTraits<RetT (&)(ErrT &)> {}; |
891 | |
892 | // Specialization for member functions of the form 'RetT (const ErrT&)'. |
893 | template <typename C, typename RetT, typename ErrT> |
894 | class ErrorHandlerTraits<RetT (C::*)(const ErrT &)> |
895 | : public ErrorHandlerTraits<RetT (&)(ErrT &)> {}; |
896 | |
897 | // Specialization for member functions of the form 'RetT (const ErrT&) const'. |
898 | template <typename C, typename RetT, typename ErrT> |
899 | class ErrorHandlerTraits<RetT (C::*)(const ErrT &) const> |
900 | : public ErrorHandlerTraits<RetT (&)(ErrT &)> {}; |
901 | |
902 | /// Specialization for member functions of the form |
903 | /// 'RetT (std::unique_ptr<ErrT>)'. |
904 | template <typename C, typename RetT, typename ErrT> |
905 | class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>)> |
906 | : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {}; |
907 | |
908 | /// Specialization for member functions of the form |
909 | /// 'RetT (std::unique_ptr<ErrT>) const'. |
910 | template <typename C, typename RetT, typename ErrT> |
911 | class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>) const> |
912 | : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {}; |
913 | |
914 | inline Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload) { |
915 | return Error(std::move(Payload)); |
916 | } |
917 | |
918 | template <typename HandlerT, typename... HandlerTs> |
919 | Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload, |
920 | HandlerT &&Handler, HandlerTs &&... Handlers) { |
921 | if (ErrorHandlerTraits<HandlerT>::appliesTo(*Payload)) |
922 | return ErrorHandlerTraits<HandlerT>::apply(std::forward<HandlerT>(Handler), |
923 | std::move(Payload)); |
924 | return handleErrorImpl(std::move(Payload), |
925 | std::forward<HandlerTs>(Handlers)...); |
926 | } |
927 | |
928 | /// Pass the ErrorInfo(s) contained in E to their respective handlers. Any |
929 | /// unhandled errors (or Errors returned by handlers) are re-concatenated and |
930 | /// returned. |
931 | /// Because this function returns an error, its result must also be checked |
932 | /// or returned. If you intend to handle all errors use handleAllErrors |
933 | /// (which returns void, and will abort() on unhandled errors) instead. |
934 | template <typename... HandlerTs> |
935 | Error handleErrors(Error E, HandlerTs &&... Hs) { |
936 | if (!E) |
937 | return Error::success(); |
938 | |
939 | std::unique_ptr<ErrorInfoBase> Payload = E.takePayload(); |
940 | |
941 | if (Payload->isA<ErrorList>()) { |
942 | ErrorList &List = static_cast<ErrorList &>(*Payload); |
943 | Error R; |
944 | for (auto &P : List.Payloads) |
945 | R = ErrorList::join( |
946 | std::move(R), |
947 | handleErrorImpl(std::move(P), std::forward<HandlerTs>(Hs)...)); |
948 | return R; |
949 | } |
950 | |
951 | return handleErrorImpl(std::move(Payload), std::forward<HandlerTs>(Hs)...); |
952 | } |
953 | |
954 | /// Behaves the same as handleErrors, except that by contract all errors |
955 | /// *must* be handled by the given handlers (i.e. there must be no remaining |
956 | /// errors after running the handlers, or llvm_unreachable is called). |
957 | template <typename... HandlerTs> |
958 | void handleAllErrors(Error E, HandlerTs &&... Handlers) { |
959 | cantFail(handleErrors(std::move(E), std::forward<HandlerTs>(Handlers)...)); |
960 | } |
961 | |
962 | /// Check that E is a non-error, then drop it. |
963 | /// If E is an error, llvm_unreachable will be called. |
964 | inline void handleAllErrors(Error E) { |
965 | cantFail(std::move(E)); |
966 | } |
967 | |
968 | /// Handle any errors (if present) in an Expected<T>, then try a recovery path. |
969 | /// |
970 | /// If the incoming value is a success value it is returned unmodified. If it |
971 | /// is a failure value then it the contained error is passed to handleErrors. |
972 | /// If handleErrors is able to handle the error then the RecoveryPath functor |
973 | /// is called to supply the final result. If handleErrors is not able to |
974 | /// handle all errors then the unhandled errors are returned. |
975 | /// |
976 | /// This utility enables the follow pattern: |
977 | /// |
978 | /// @code{.cpp} |
979 | /// enum FooStrategy { Aggressive, Conservative }; |
980 | /// Expected<Foo> foo(FooStrategy S); |
981 | /// |
982 | /// auto ResultOrErr = |
983 | /// handleExpected( |
984 | /// foo(Aggressive), |
985 | /// []() { return foo(Conservative); }, |
986 | /// [](AggressiveStrategyError&) { |
987 | /// // Implicitly conusme this - we'll recover by using a conservative |
988 | /// // strategy. |
989 | /// }); |
990 | /// |
991 | /// @endcode |
992 | template <typename T, typename RecoveryFtor, typename... HandlerTs> |
993 | Expected<T> handleExpected(Expected<T> ValOrErr, RecoveryFtor &&RecoveryPath, |
994 | HandlerTs &&... Handlers) { |
995 | if (ValOrErr) |
996 | return ValOrErr; |
997 | |
998 | if (auto Err = handleErrors(ValOrErr.takeError(), |
999 | std::forward<HandlerTs>(Handlers)...)) |
1000 | return std::move(Err); |
1001 | |
1002 | return RecoveryPath(); |
1003 | } |
1004 | |
1005 | /// Log all errors (if any) in E to OS. If there are any errors, ErrorBanner |
1006 | /// will be printed before the first one is logged. A newline will be printed |
1007 | /// after each error. |
1008 | /// |
1009 | /// This function is compatible with the helpers from Support/WithColor.h. You |
1010 | /// can pass any of them as the OS. Please consider using them instead of |
1011 | /// including 'error: ' in the ErrorBanner. |
1012 | /// |
1013 | /// This is useful in the base level of your program to allow clean termination |
1014 | /// (allowing clean deallocation of resources, etc.), while reporting error |
1015 | /// information to the user. |
1016 | void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner = {}); |
1017 | |
1018 | /// Write all error messages (if any) in E to a string. The newline character |
1019 | /// is used to separate error messages. |
1020 | inline std::string toString(Error E) { |
1021 | SmallVector<std::string, 2> Errors; |
1022 | handleAllErrors(std::move(E), [&Errors](const ErrorInfoBase &EI) { |
1023 | Errors.push_back(EI.message()); |
1024 | }); |
1025 | return join(Errors.begin(), Errors.end(), "\n"); |
1026 | } |
1027 | |
1028 | /// Consume a Error without doing anything. This method should be used |
1029 | /// only where an error can be considered a reasonable and expected return |
1030 | /// value. |
1031 | /// |
1032 | /// Uses of this method are potentially indicative of design problems: If it's |
1033 | /// legitimate to do nothing while processing an "error", the error-producer |
1034 | /// might be more clearly refactored to return an Optional<T>. |
1035 | inline void consumeError(Error Err) { |
1036 | handleAllErrors(std::move(Err), [](const ErrorInfoBase &) {}); |
1037 | } |
1038 | |
1039 | /// Convert an Expected to an Optional without doing anything. This method |
1040 | /// should be used only where an error can be considered a reasonable and |
1041 | /// expected return value. |
1042 | /// |
1043 | /// Uses of this method are potentially indicative of problems: perhaps the |
1044 | /// error should be propagated further, or the error-producer should just |
1045 | /// return an Optional in the first place. |
1046 | template <typename T> Optional<T> expectedToOptional(Expected<T> &&E) { |
1047 | if (E) |
1048 | return std::move(*E); |
1049 | consumeError(E.takeError()); |
1050 | return None; |
1051 | } |
1052 | |
1053 | /// Helper for converting an Error to a bool. |
1054 | /// |
1055 | /// This method returns true if Err is in an error state, or false if it is |
1056 | /// in a success state. Puts Err in a checked state in both cases (unlike |
1057 | /// Error::operator bool(), which only does this for success states). |
1058 | inline bool errorToBool(Error Err) { |
1059 | bool IsError = static_cast<bool>(Err); |
1060 | if (IsError) |
1061 | consumeError(std::move(Err)); |
1062 | return IsError; |
1063 | } |
1064 | |
1065 | /// Helper for Errors used as out-parameters. |
1066 | /// |
1067 | /// This helper is for use with the Error-as-out-parameter idiom, where an error |
1068 | /// is passed to a function or method by reference, rather than being returned. |
1069 | /// In such cases it is helpful to set the checked bit on entry to the function |
1070 | /// so that the error can be written to (unchecked Errors abort on assignment) |
1071 | /// and clear the checked bit on exit so that clients cannot accidentally forget |
1072 | /// to check the result. This helper performs these actions automatically using |
1073 | /// RAII: |
1074 | /// |
1075 | /// @code{.cpp} |
1076 | /// Result foo(Error &Err) { |
1077 | /// ErrorAsOutParameter ErrAsOutParam(&Err); // 'Checked' flag set |
1078 | /// // <body of foo> |
1079 | /// // <- 'Checked' flag auto-cleared when ErrAsOutParam is destructed. |
1080 | /// } |
1081 | /// @endcode |
1082 | /// |
1083 | /// ErrorAsOutParameter takes an Error* rather than Error& so that it can be |
1084 | /// used with optional Errors (Error pointers that are allowed to be null). If |
1085 | /// ErrorAsOutParameter took an Error reference, an instance would have to be |
1086 | /// created inside every condition that verified that Error was non-null. By |
1087 | /// taking an Error pointer we can just create one instance at the top of the |
1088 | /// function. |
1089 | class ErrorAsOutParameter { |
1090 | public: |
1091 | ErrorAsOutParameter(Error *Err) : Err(Err) { |
1092 | // Raise the checked bit if Err is success. |
1093 | if (Err) |
1094 | (void)!!*Err; |
1095 | } |
1096 | |
1097 | ~ErrorAsOutParameter() { |
1098 | // Clear the checked bit. |
1099 | if (Err && !*Err) |
1100 | *Err = Error::success(); |
1101 | } |
1102 | |
1103 | private: |
1104 | Error *Err; |
1105 | }; |
1106 | |
1107 | /// Helper for Expected<T>s used as out-parameters. |
1108 | /// |
1109 | /// See ErrorAsOutParameter. |
1110 | template <typename T> |
1111 | class ExpectedAsOutParameter { |
1112 | public: |
1113 | ExpectedAsOutParameter(Expected<T> *ValOrErr) |
1114 | : ValOrErr(ValOrErr) { |
1115 | if (ValOrErr) |
1116 | (void)!!*ValOrErr; |
1117 | } |
1118 | |
1119 | ~ExpectedAsOutParameter() { |
1120 | if (ValOrErr) |
1121 | ValOrErr->setUnchecked(); |
1122 | } |
1123 | |
1124 | private: |
1125 | Expected<T> *ValOrErr; |
1126 | }; |
1127 | |
1128 | /// This class wraps a std::error_code in a Error. |
1129 | /// |
1130 | /// This is useful if you're writing an interface that returns a Error |
1131 | /// (or Expected) and you want to call code that still returns |
1132 | /// std::error_codes. |
1133 | class ECError : public ErrorInfo<ECError> { |
1134 | friend Error errorCodeToError(std::error_code); |
1135 | |
1136 | virtual void anchor() override; |
1137 | |
1138 | public: |
1139 | void setErrorCode(std::error_code EC) { this->EC = EC; } |
1140 | std::error_code convertToErrorCode() const override { return EC; } |
1141 | void log(raw_ostream &OS) const override { OS << EC.message(); } |
1142 | |
1143 | // Used by ErrorInfo::classID. |
1144 | static char ID; |
1145 | |
1146 | protected: |
1147 | ECError() = default; |
1148 | ECError(std::error_code EC) : EC(EC) {} |
1149 | |
1150 | std::error_code EC; |
1151 | }; |
1152 | |
1153 | /// The value returned by this function can be returned from convertToErrorCode |
1154 | /// for Error values where no sensible translation to std::error_code exists. |
1155 | /// It should only be used in this situation, and should never be used where a |
1156 | /// sensible conversion to std::error_code is available, as attempts to convert |
1157 | /// to/from this error will result in a fatal error. (i.e. it is a programmatic |
1158 | ///error to try to convert such a value). |
1159 | std::error_code inconvertibleErrorCode(); |
1160 | |
1161 | /// Helper for converting an std::error_code to a Error. |
1162 | Error errorCodeToError(std::error_code EC); |
1163 | |
1164 | /// Helper for converting an ECError to a std::error_code. |
1165 | /// |
1166 | /// This method requires that Err be Error() or an ECError, otherwise it |
1167 | /// will trigger a call to abort(). |
1168 | std::error_code errorToErrorCode(Error Err); |
1169 | |
1170 | /// Convert an ErrorOr<T> to an Expected<T>. |
1171 | template <typename T> Expected<T> errorOrToExpected(ErrorOr<T> &&EO) { |
1172 | if (auto EC = EO.getError()) |
1173 | return errorCodeToError(EC); |
1174 | return std::move(*EO); |
1175 | } |
1176 | |
1177 | /// Convert an Expected<T> to an ErrorOr<T>. |
1178 | template <typename T> ErrorOr<T> expectedToErrorOr(Expected<T> &&E) { |
1179 | if (auto Err = E.takeError()) |
1180 | return errorToErrorCode(std::move(Err)); |
1181 | return std::move(*E); |
1182 | } |
1183 | |
1184 | /// This class wraps a string in an Error. |
1185 | /// |
1186 | /// StringError is useful in cases where the client is not expected to be able |
1187 | /// to consume the specific error message programmatically (for example, if the |
1188 | /// error message is to be presented to the user). |
1189 | /// |
1190 | /// StringError can also be used when additional information is to be printed |
1191 | /// along with a error_code message. Depending on the constructor called, this |
1192 | /// class can either display: |
1193 | /// 1. the error_code message (ECError behavior) |
1194 | /// 2. a string |
1195 | /// 3. the error_code message and a string |
1196 | /// |
1197 | /// These behaviors are useful when subtyping is required; for example, when a |
1198 | /// specific library needs an explicit error type. In the example below, |
1199 | /// PDBError is derived from StringError: |
1200 | /// |
1201 | /// @code{.cpp} |
1202 | /// Expected<int> foo() { |
1203 | /// return llvm::make_error<PDBError>(pdb_error_code::dia_failed_loading, |
1204 | /// "Additional information"); |
1205 | /// } |
1206 | /// @endcode |
1207 | /// |
1208 | class StringError : public ErrorInfo<StringError> { |
1209 | public: |
1210 | static char ID; |
1211 | |
1212 | // Prints EC + S and converts to EC |
1213 | StringError(std::error_code EC, const Twine &S = Twine()); |
1214 | |
1215 | // Prints S and converts to EC |
1216 | StringError(const Twine &S, std::error_code EC); |
1217 | |
1218 | void log(raw_ostream &OS) const override; |
1219 | std::error_code convertToErrorCode() const override; |
1220 | |
1221 | const std::string &getMessage() const { return Msg; } |
1222 | |
1223 | private: |
1224 | std::string Msg; |
1225 | std::error_code EC; |
1226 | const bool PrintMsgOnly = false; |
1227 | }; |
1228 | |
1229 | /// Create formatted StringError object. |
1230 | template <typename... Ts> |
1231 | inline Error createStringError(std::error_code EC, char const *Fmt, |
1232 | const Ts &... Vals) { |
1233 | std::string Buffer; |
1234 | raw_string_ostream Stream(Buffer); |
1235 | Stream << format(Fmt, Vals...); |
1236 | return make_error<StringError>(Stream.str(), EC); |
1237 | } |
1238 | |
1239 | Error createStringError(std::error_code EC, char const *Msg); |
1240 | |
1241 | inline Error createStringError(std::error_code EC, const Twine &S) { |
1242 | return createStringError(EC, S.str().c_str()); |
1243 | } |
1244 | |
1245 | template <typename... Ts> |
1246 | inline Error createStringError(std::errc EC, char const *Fmt, |
1247 | const Ts &... Vals) { |
1248 | return createStringError(std::make_error_code(EC), Fmt, Vals...); |
1249 | } |
1250 | |
1251 | /// This class wraps a filename and another Error. |
1252 | /// |
1253 | /// In some cases, an error needs to live along a 'source' name, in order to |
1254 | /// show more detailed information to the user. |
1255 | class FileError final : public ErrorInfo<FileError> { |
1256 | |
1257 | friend Error createFileError(const Twine &, Error); |
1258 | friend Error createFileError(const Twine &, size_t, Error); |
1259 | |
1260 | public: |
1261 | void log(raw_ostream &OS) const override { |
1262 | assert(Err && !FileName.empty() && "Trying to log after takeError().")(static_cast<void> (0)); |
1263 | OS << "'" << FileName << "': "; |
1264 | if (Line.hasValue()) |
1265 | OS << "line " << Line.getValue() << ": "; |
1266 | Err->log(OS); |
1267 | } |
1268 | |
1269 | StringRef getFileName() { return FileName; } |
1270 | |
1271 | Error takeError() { return Error(std::move(Err)); } |
1272 | |
1273 | std::error_code convertToErrorCode() const override; |
1274 | |
1275 | // Used by ErrorInfo::classID. |
1276 | static char ID; |
1277 | |
1278 | private: |
1279 | FileError(const Twine &F, Optional<size_t> LineNum, |
1280 | std::unique_ptr<ErrorInfoBase> E) { |
1281 | assert(E && "Cannot create FileError from Error success value.")(static_cast<void> (0)); |
1282 | assert(!F.isTriviallyEmpty() &&(static_cast<void> (0)) |
1283 | "The file name provided to FileError must not be empty.")(static_cast<void> (0)); |
1284 | FileName = F.str(); |
1285 | Err = std::move(E); |
1286 | Line = std::move(LineNum); |
1287 | } |
1288 | |
1289 | static Error build(const Twine &F, Optional<size_t> Line, Error E) { |
1290 | std::unique_ptr<ErrorInfoBase> Payload; |
1291 | handleAllErrors(std::move(E), |
1292 | [&](std::unique_ptr<ErrorInfoBase> EIB) -> Error { |
1293 | Payload = std::move(EIB); |
1294 | return Error::success(); |
1295 | }); |
1296 | return Error( |
1297 | std::unique_ptr<FileError>(new FileError(F, Line, std::move(Payload)))); |
1298 | } |
1299 | |
1300 | std::string FileName; |
1301 | Optional<size_t> Line; |
1302 | std::unique_ptr<ErrorInfoBase> Err; |
1303 | }; |
1304 | |
1305 | /// Concatenate a source file path and/or name with an Error. The resulting |
1306 | /// Error is unchecked. |
1307 | inline Error createFileError(const Twine &F, Error E) { |
1308 | return FileError::build(F, Optional<size_t>(), std::move(E)); |
1309 | } |
1310 | |
1311 | /// Concatenate a source file path and/or name with line number and an Error. |
1312 | /// The resulting Error is unchecked. |
1313 | inline Error createFileError(const Twine &F, size_t Line, Error E) { |
1314 | return FileError::build(F, Optional<size_t>(Line), std::move(E)); |
1315 | } |
1316 | |
1317 | /// Concatenate a source file path and/or name with a std::error_code |
1318 | /// to form an Error object. |
1319 | inline Error createFileError(const Twine &F, std::error_code EC) { |
1320 | return createFileError(F, errorCodeToError(EC)); |
1321 | } |
1322 | |
1323 | /// Concatenate a source file path and/or name with line number and |
1324 | /// std::error_code to form an Error object. |
1325 | inline Error createFileError(const Twine &F, size_t Line, std::error_code EC) { |
1326 | return createFileError(F, Line, errorCodeToError(EC)); |
1327 | } |
1328 | |
1329 | Error createFileError(const Twine &F, ErrorSuccess) = delete; |
1330 | |
1331 | /// Helper for check-and-exit error handling. |
1332 | /// |
1333 | /// For tool use only. NOT FOR USE IN LIBRARY CODE. |
1334 | /// |
1335 | class ExitOnError { |
1336 | public: |
1337 | /// Create an error on exit helper. |
1338 | ExitOnError(std::string Banner = "", int DefaultErrorExitCode = 1) |
1339 | : Banner(std::move(Banner)), |
1340 | GetExitCode([=](const Error &) { return DefaultErrorExitCode; }) {} |
1341 | |
1342 | /// Set the banner string for any errors caught by operator(). |
1343 | void setBanner(std::string Banner) { this->Banner = std::move(Banner); } |
1344 | |
1345 | /// Set the exit-code mapper function. |
1346 | void setExitCodeMapper(std::function<int(const Error &)> GetExitCode) { |
1347 | this->GetExitCode = std::move(GetExitCode); |
1348 | } |
1349 | |
1350 | /// Check Err. If it's in a failure state log the error(s) and exit. |
1351 | void operator()(Error Err) const { checkError(std::move(Err)); } |
1352 | |
1353 | /// Check E. If it's in a success state then return the contained value. If |
1354 | /// it's in a failure state log the error(s) and exit. |
1355 | template <typename T> T operator()(Expected<T> &&E) const { |
1356 | checkError(E.takeError()); |
1357 | return std::move(*E); |
1358 | } |
1359 | |
1360 | /// Check E. If it's in a success state then return the contained reference. If |
1361 | /// it's in a failure state log the error(s) and exit. |
1362 | template <typename T> T& operator()(Expected<T&> &&E) const { |
1363 | checkError(E.takeError()); |
1364 | return *E; |
1365 | } |
1366 | |
1367 | private: |
1368 | void checkError(Error Err) const { |
1369 | if (Err) { |
1370 | int ExitCode = GetExitCode(Err); |
1371 | logAllUnhandledErrors(std::move(Err), errs(), Banner); |
1372 | exit(ExitCode); |
1373 | } |
1374 | } |
1375 | |
1376 | std::string Banner; |
1377 | std::function<int(const Error &)> GetExitCode; |
1378 | }; |
1379 | |
1380 | /// Conversion from Error to LLVMErrorRef for C error bindings. |
1381 | inline LLVMErrorRef wrap(Error Err) { |
1382 | return reinterpret_cast<LLVMErrorRef>(Err.takePayload().release()); |
1383 | } |
1384 | |
1385 | /// Conversion from LLVMErrorRef to Error for C error bindings. |
1386 | inline Error unwrap(LLVMErrorRef ErrRef) { |
1387 | return Error(std::unique_ptr<ErrorInfoBase>( |
1388 | reinterpret_cast<ErrorInfoBase *>(ErrRef))); |
1389 | } |
1390 | |
1391 | } // end namespace llvm |
1392 | |
1393 | #endif // LLVM_SUPPORT_ERROR_H |