File: | src/gnu/usr.bin/clang/liblldbAPI/../../../llvm/llvm/include/llvm/Support/Error.h |
Warning: | line 744, column 7 Value stored to 'Msg' is never read |
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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 | LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn)) |
261 | void fatalUncheckedError() const; |
262 | #endif |
263 | |
264 | void assertIsChecked() { |
265 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
266 | if (LLVM_UNLIKELY(!getChecked() || getPtr())__builtin_expect((bool)(!getChecked() || getPtr()), false)) |
267 | fatalUncheckedError(); |
268 | #endif |
269 | } |
270 | |
271 | ErrorInfoBase *getPtr() const { |
272 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
273 | return reinterpret_cast<ErrorInfoBase*>( |
274 | reinterpret_cast<uintptr_t>(Payload) & |
275 | ~static_cast<uintptr_t>(0x1)); |
276 | #else |
277 | return Payload; |
278 | #endif |
279 | } |
280 | |
281 | void setPtr(ErrorInfoBase *EI) { |
282 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
283 | Payload = reinterpret_cast<ErrorInfoBase*>( |
284 | (reinterpret_cast<uintptr_t>(EI) & |
285 | ~static_cast<uintptr_t>(0x1)) | |
286 | (reinterpret_cast<uintptr_t>(Payload) & 0x1)); |
287 | #else |
288 | Payload = EI; |
289 | #endif |
290 | } |
291 | |
292 | bool getChecked() const { |
293 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
294 | return (reinterpret_cast<uintptr_t>(Payload) & 0x1) == 0; |
295 | #else |
296 | return true; |
297 | #endif |
298 | } |
299 | |
300 | void setChecked(bool V) { |
301 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
302 | Payload = reinterpret_cast<ErrorInfoBase*>( |
303 | (reinterpret_cast<uintptr_t>(Payload) & |
304 | ~static_cast<uintptr_t>(0x1)) | |
305 | (V ? 0 : 1)); |
306 | #endif |
307 | } |
308 | |
309 | std::unique_ptr<ErrorInfoBase> takePayload() { |
310 | std::unique_ptr<ErrorInfoBase> Tmp(getPtr()); |
311 | setPtr(nullptr); |
312 | setChecked(true); |
313 | return Tmp; |
314 | } |
315 | |
316 | friend raw_ostream &operator<<(raw_ostream &OS, const Error &E) { |
317 | if (auto P = E.getPtr()) |
318 | P->log(OS); |
319 | else |
320 | OS << "success"; |
321 | return OS; |
322 | } |
323 | |
324 | ErrorInfoBase *Payload = nullptr; |
325 | }; |
326 | |
327 | /// Subclass of Error for the sole purpose of identifying the success path in |
328 | /// the type system. This allows to catch invalid conversion to Expected<T> at |
329 | /// compile time. |
330 | class ErrorSuccess final : public Error {}; |
331 | |
332 | inline ErrorSuccess Error::success() { return ErrorSuccess(); } |
333 | |
334 | /// Make a Error instance representing failure using the given error info |
335 | /// type. |
336 | template <typename ErrT, typename... ArgTs> Error make_error(ArgTs &&... Args) { |
337 | return Error(std::make_unique<ErrT>(std::forward<ArgTs>(Args)...)); |
338 | } |
339 | |
340 | /// Base class for user error types. Users should declare their error types |
341 | /// like: |
342 | /// |
343 | /// class MyError : public ErrorInfo<MyError> { |
344 | /// .... |
345 | /// }; |
346 | /// |
347 | /// This class provides an implementation of the ErrorInfoBase::kind |
348 | /// method, which is used by the Error RTTI system. |
349 | template <typename ThisErrT, typename ParentErrT = ErrorInfoBase> |
350 | class ErrorInfo : public ParentErrT { |
351 | public: |
352 | using ParentErrT::ParentErrT; // inherit constructors |
353 | |
354 | static const void *classID() { return &ThisErrT::ID; } |
355 | |
356 | const void *dynamicClassID() const override { return &ThisErrT::ID; } |
357 | |
358 | bool isA(const void *const ClassID) const override { |
359 | return ClassID == classID() || ParentErrT::isA(ClassID); |
360 | } |
361 | }; |
362 | |
363 | /// Special ErrorInfo subclass representing a list of ErrorInfos. |
364 | /// Instances of this class are constructed by joinError. |
365 | class ErrorList final : public ErrorInfo<ErrorList> { |
366 | // handleErrors needs to be able to iterate the payload list of an |
367 | // ErrorList. |
368 | template <typename... HandlerTs> |
369 | friend Error handleErrors(Error E, HandlerTs &&... Handlers); |
370 | |
371 | // joinErrors is implemented in terms of join. |
372 | friend Error joinErrors(Error, Error); |
373 | |
374 | public: |
375 | void log(raw_ostream &OS) const override { |
376 | OS << "Multiple errors:\n"; |
377 | for (auto &ErrPayload : Payloads) { |
378 | ErrPayload->log(OS); |
379 | OS << "\n"; |
380 | } |
381 | } |
382 | |
383 | std::error_code convertToErrorCode() const override; |
384 | |
385 | // Used by ErrorInfo::classID. |
386 | static char ID; |
387 | |
388 | private: |
389 | ErrorList(std::unique_ptr<ErrorInfoBase> Payload1, |
390 | std::unique_ptr<ErrorInfoBase> Payload2) { |
391 | assert(!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() &&((void)0) |
392 | "ErrorList constructor payloads should be singleton errors")((void)0); |
393 | Payloads.push_back(std::move(Payload1)); |
394 | Payloads.push_back(std::move(Payload2)); |
395 | } |
396 | |
397 | static Error join(Error E1, Error E2) { |
398 | if (!E1) |
399 | return E2; |
400 | if (!E2) |
401 | return E1; |
402 | if (E1.isA<ErrorList>()) { |
403 | auto &E1List = static_cast<ErrorList &>(*E1.getPtr()); |
404 | if (E2.isA<ErrorList>()) { |
405 | auto E2Payload = E2.takePayload(); |
406 | auto &E2List = static_cast<ErrorList &>(*E2Payload); |
407 | for (auto &Payload : E2List.Payloads) |
408 | E1List.Payloads.push_back(std::move(Payload)); |
409 | } else |
410 | E1List.Payloads.push_back(E2.takePayload()); |
411 | |
412 | return E1; |
413 | } |
414 | if (E2.isA<ErrorList>()) { |
415 | auto &E2List = static_cast<ErrorList &>(*E2.getPtr()); |
416 | E2List.Payloads.insert(E2List.Payloads.begin(), E1.takePayload()); |
417 | return E2; |
418 | } |
419 | return Error(std::unique_ptr<ErrorList>( |
420 | new ErrorList(E1.takePayload(), E2.takePayload()))); |
421 | } |
422 | |
423 | std::vector<std::unique_ptr<ErrorInfoBase>> Payloads; |
424 | }; |
425 | |
426 | /// Concatenate errors. The resulting Error is unchecked, and contains the |
427 | /// ErrorInfo(s), if any, contained in E1, followed by the |
428 | /// ErrorInfo(s), if any, contained in E2. |
429 | inline Error joinErrors(Error E1, Error E2) { |
430 | return ErrorList::join(std::move(E1), std::move(E2)); |
431 | } |
432 | |
433 | /// Tagged union holding either a T or a Error. |
434 | /// |
435 | /// This class parallels ErrorOr, but replaces error_code with Error. Since |
436 | /// Error cannot be copied, this class replaces getError() with |
437 | /// takeError(). It also adds an bool errorIsA<ErrT>() method for testing the |
438 | /// error class type. |
439 | /// |
440 | /// Example usage of 'Expected<T>' as a function return type: |
441 | /// |
442 | /// @code{.cpp} |
443 | /// Expected<int> myDivide(int A, int B) { |
444 | /// if (B == 0) { |
445 | /// // return an Error |
446 | /// return createStringError(inconvertibleErrorCode(), |
447 | /// "B must not be zero!"); |
448 | /// } |
449 | /// // return an integer |
450 | /// return A / B; |
451 | /// } |
452 | /// @endcode |
453 | /// |
454 | /// Checking the results of to a function returning 'Expected<T>': |
455 | /// @code{.cpp} |
456 | /// if (auto E = Result.takeError()) { |
457 | /// // We must consume the error. Typically one of: |
458 | /// // - return the error to our caller |
459 | /// // - toString(), when logging |
460 | /// // - consumeError(), to silently swallow the error |
461 | /// // - handleErrors(), to distinguish error types |
462 | /// errs() << "Problem with division " << toString(std::move(E)) << "\n"; |
463 | /// return; |
464 | /// } |
465 | /// // use the result |
466 | /// outs() << "The answer is " << *Result << "\n"; |
467 | /// @endcode |
468 | /// |
469 | /// For unit-testing a function returning an 'Expceted<T>', see the |
470 | /// 'EXPECT_THAT_EXPECTED' macros in llvm/Testing/Support/Error.h |
471 | |
472 | template <class T> class LLVM_NODISCARD[[clang::warn_unused_result]] Expected { |
473 | template <class T1> friend class ExpectedAsOutParameter; |
474 | template <class OtherT> friend class Expected; |
475 | |
476 | static constexpr bool isRef = std::is_reference<T>::value; |
477 | |
478 | using wrap = std::reference_wrapper<std::remove_reference_t<T>>; |
479 | |
480 | using error_type = std::unique_ptr<ErrorInfoBase>; |
481 | |
482 | public: |
483 | using storage_type = std::conditional_t<isRef, wrap, T>; |
484 | using value_type = T; |
485 | |
486 | private: |
487 | using reference = std::remove_reference_t<T> &; |
488 | using const_reference = const std::remove_reference_t<T> &; |
489 | using pointer = std::remove_reference_t<T> *; |
490 | using const_pointer = const std::remove_reference_t<T> *; |
491 | |
492 | public: |
493 | /// Create an Expected<T> error value from the given Error. |
494 | Expected(Error Err) |
495 | : HasError(true) |
496 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
497 | // Expected is unchecked upon construction in Debug builds. |
498 | , Unchecked(true) |
499 | #endif |
500 | { |
501 | assert(Err && "Cannot create Expected<T> from Error success value.")((void)0); |
502 | new (getErrorStorage()) error_type(Err.takePayload()); |
503 | } |
504 | |
505 | /// Forbid to convert from Error::success() implicitly, this avoids having |
506 | /// Expected<T> foo() { return Error::success(); } which compiles otherwise |
507 | /// but triggers the assertion above. |
508 | Expected(ErrorSuccess) = delete; |
509 | |
510 | /// Create an Expected<T> success value from the given OtherT value, which |
511 | /// must be convertible to T. |
512 | template <typename OtherT> |
513 | Expected(OtherT &&Val, |
514 | std::enable_if_t<std::is_convertible<OtherT, T>::value> * = nullptr) |
515 | : HasError(false) |
516 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
517 | // Expected is unchecked upon construction in Debug builds. |
518 | , |
519 | Unchecked(true) |
520 | #endif |
521 | { |
522 | new (getStorage()) storage_type(std::forward<OtherT>(Val)); |
523 | } |
524 | |
525 | /// Move construct an Expected<T> value. |
526 | Expected(Expected &&Other) { moveConstruct(std::move(Other)); } |
527 | |
528 | /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT |
529 | /// must be convertible to T. |
530 | template <class OtherT> |
531 | Expected( |
532 | Expected<OtherT> &&Other, |
533 | std::enable_if_t<std::is_convertible<OtherT, T>::value> * = nullptr) { |
534 | moveConstruct(std::move(Other)); |
535 | } |
536 | |
537 | /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT |
538 | /// isn't convertible to T. |
539 | template <class OtherT> |
540 | explicit Expected( |
541 | Expected<OtherT> &&Other, |
542 | std::enable_if_t<!std::is_convertible<OtherT, T>::value> * = nullptr) { |
543 | moveConstruct(std::move(Other)); |
544 | } |
545 | |
546 | /// Move-assign from another Expected<T>. |
547 | Expected &operator=(Expected &&Other) { |
548 | moveAssign(std::move(Other)); |
549 | return *this; |
550 | } |
551 | |
552 | /// Destroy an Expected<T>. |
553 | ~Expected() { |
554 | assertIsChecked(); |
555 | if (!HasError) |
556 | getStorage()->~storage_type(); |
557 | else |
558 | getErrorStorage()->~error_type(); |
559 | } |
560 | |
561 | /// Return false if there is an error. |
562 | explicit operator bool() { |
563 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
564 | Unchecked = HasError; |
565 | #endif |
566 | return !HasError; |
567 | } |
568 | |
569 | /// Returns a reference to the stored T value. |
570 | reference get() { |
571 | assertIsChecked(); |
572 | return *getStorage(); |
573 | } |
574 | |
575 | /// Returns a const reference to the stored T value. |
576 | const_reference get() const { |
577 | assertIsChecked(); |
578 | return const_cast<Expected<T> *>(this)->get(); |
579 | } |
580 | |
581 | /// Check that this Expected<T> is an error of type ErrT. |
582 | template <typename ErrT> bool errorIsA() const { |
583 | return HasError && (*getErrorStorage())->template isA<ErrT>(); |
584 | } |
585 | |
586 | /// Take ownership of the stored error. |
587 | /// After calling this the Expected<T> is in an indeterminate state that can |
588 | /// only be safely destructed. No further calls (beside the destructor) should |
589 | /// be made on the Expected<T> value. |
590 | Error takeError() { |
591 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
592 | Unchecked = false; |
593 | #endif |
594 | return HasError ? Error(std::move(*getErrorStorage())) : Error::success(); |
595 | } |
596 | |
597 | /// Returns a pointer to the stored T value. |
598 | pointer operator->() { |
599 | assertIsChecked(); |
600 | return toPointer(getStorage()); |
601 | } |
602 | |
603 | /// Returns a const pointer to the stored T value. |
604 | const_pointer operator->() const { |
605 | assertIsChecked(); |
606 | return toPointer(getStorage()); |
607 | } |
608 | |
609 | /// Returns a reference to the stored T value. |
610 | reference operator*() { |
611 | assertIsChecked(); |
612 | return *getStorage(); |
613 | } |
614 | |
615 | /// Returns a const reference to the stored T value. |
616 | const_reference operator*() const { |
617 | assertIsChecked(); |
618 | return *getStorage(); |
619 | } |
620 | |
621 | private: |
622 | template <class T1> |
623 | static bool compareThisIfSameType(const T1 &a, const T1 &b) { |
624 | return &a == &b; |
625 | } |
626 | |
627 | template <class T1, class T2> |
628 | static bool compareThisIfSameType(const T1 &, const T2 &) { |
629 | return false; |
630 | } |
631 | |
632 | template <class OtherT> void moveConstruct(Expected<OtherT> &&Other) { |
633 | HasError = Other.HasError; |
634 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
635 | Unchecked = true; |
636 | Other.Unchecked = false; |
637 | #endif |
638 | |
639 | if (!HasError) |
640 | new (getStorage()) storage_type(std::move(*Other.getStorage())); |
641 | else |
642 | new (getErrorStorage()) error_type(std::move(*Other.getErrorStorage())); |
643 | } |
644 | |
645 | template <class OtherT> void moveAssign(Expected<OtherT> &&Other) { |
646 | assertIsChecked(); |
647 | |
648 | if (compareThisIfSameType(*this, Other)) |
649 | return; |
650 | |
651 | this->~Expected(); |
652 | new (this) Expected(std::move(Other)); |
653 | } |
654 | |
655 | pointer toPointer(pointer Val) { return Val; } |
656 | |
657 | const_pointer toPointer(const_pointer Val) const { return Val; } |
658 | |
659 | pointer toPointer(wrap *Val) { return &Val->get(); } |
660 | |
661 | const_pointer toPointer(const wrap *Val) const { return &Val->get(); } |
662 | |
663 | storage_type *getStorage() { |
664 | assert(!HasError && "Cannot get value when an error exists!")((void)0); |
665 | return reinterpret_cast<storage_type *>(&TStorage); |
666 | } |
667 | |
668 | const storage_type *getStorage() const { |
669 | assert(!HasError && "Cannot get value when an error exists!")((void)0); |
670 | return reinterpret_cast<const storage_type *>(&TStorage); |
671 | } |
672 | |
673 | error_type *getErrorStorage() { |
674 | assert(HasError && "Cannot get error when a value exists!")((void)0); |
675 | return reinterpret_cast<error_type *>(&ErrorStorage); |
676 | } |
677 | |
678 | const error_type *getErrorStorage() const { |
679 | assert(HasError && "Cannot get error when a value exists!")((void)0); |
680 | return reinterpret_cast<const error_type *>(&ErrorStorage); |
681 | } |
682 | |
683 | // Used by ExpectedAsOutParameter to reset the checked flag. |
684 | void setUnchecked() { |
685 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
686 | Unchecked = true; |
687 | #endif |
688 | } |
689 | |
690 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
691 | LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn)) |
692 | LLVM_ATTRIBUTE_NOINLINE__attribute__((noinline)) |
693 | void fatalUncheckedExpected() const { |
694 | dbgs() << "Expected<T> must be checked before access or destruction.\n"; |
695 | if (HasError) { |
696 | dbgs() << "Unchecked Expected<T> contained error:\n"; |
697 | (*getErrorStorage())->log(dbgs()); |
698 | } else |
699 | dbgs() << "Expected<T> value was in success state. (Note: Expected<T> " |
700 | "values in success mode must still be checked prior to being " |
701 | "destroyed).\n"; |
702 | abort(); |
703 | } |
704 | #endif |
705 | |
706 | void assertIsChecked() const { |
707 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
708 | if (LLVM_UNLIKELY(Unchecked)__builtin_expect((bool)(Unchecked), false)) |
709 | fatalUncheckedExpected(); |
710 | #endif |
711 | } |
712 | |
713 | union { |
714 | AlignedCharArrayUnion<storage_type> TStorage; |
715 | AlignedCharArrayUnion<error_type> ErrorStorage; |
716 | }; |
717 | bool HasError : 1; |
718 | #if LLVM_ENABLE_ABI_BREAKING_CHECKS0 |
719 | bool Unchecked : 1; |
720 | #endif |
721 | }; |
722 | |
723 | /// Report a serious error, calling any installed error handler. See |
724 | /// ErrorHandling.h. |
725 | LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn)) void report_fatal_error(Error Err, |
726 | bool gen_crash_diag = true); |
727 | |
728 | /// Report a fatal error if Err is a failure value. |
729 | /// |
730 | /// This function can be used to wrap calls to fallible functions ONLY when it |
731 | /// is known that the Error will always be a success value. E.g. |
732 | /// |
733 | /// @code{.cpp} |
734 | /// // foo only attempts the fallible operation if DoFallibleOperation is |
735 | /// // true. If DoFallibleOperation is false then foo always returns |
736 | /// // Error::success(). |
737 | /// Error foo(bool DoFallibleOperation); |
738 | /// |
739 | /// cantFail(foo(false)); |
740 | /// @endcode |
741 | inline void cantFail(Error Err, const char *Msg = nullptr) { |
742 | if (Err) { |
743 | if (!Msg) |
744 | Msg = "Failure value returned from cantFail wrapped call"; |
Value stored to 'Msg' is never read | |
745 | #ifndef NDEBUG1 |
746 | std::string Str; |
747 | raw_string_ostream OS(Str); |
748 | OS << Msg << "\n" << Err; |
749 | Msg = OS.str().c_str(); |
750 | #endif |
751 | llvm_unreachable(Msg)__builtin_unreachable(); |
752 | } |
753 | } |
754 | |
755 | /// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and |
756 | /// returns the contained value. |
757 | /// |
758 | /// This function can be used to wrap calls to fallible functions ONLY when it |
759 | /// is known that the Error will always be a success value. E.g. |
760 | /// |
761 | /// @code{.cpp} |
762 | /// // foo only attempts the fallible operation if DoFallibleOperation is |
763 | /// // true. If DoFallibleOperation is false then foo always returns an int. |
764 | /// Expected<int> foo(bool DoFallibleOperation); |
765 | /// |
766 | /// int X = cantFail(foo(false)); |
767 | /// @endcode |
768 | template <typename T> |
769 | T cantFail(Expected<T> ValOrErr, const char *Msg = nullptr) { |
770 | if (ValOrErr) |
771 | return std::move(*ValOrErr); |
772 | else { |
773 | if (!Msg) |
774 | Msg = "Failure value returned from cantFail wrapped call"; |
775 | #ifndef NDEBUG1 |
776 | std::string Str; |
777 | raw_string_ostream OS(Str); |
778 | auto E = ValOrErr.takeError(); |
779 | OS << Msg << "\n" << E; |
780 | Msg = OS.str().c_str(); |
781 | #endif |
782 | llvm_unreachable(Msg)__builtin_unreachable(); |
783 | } |
784 | } |
785 | |
786 | /// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and |
787 | /// returns the contained reference. |
788 | /// |
789 | /// This function can be used to wrap calls to fallible functions ONLY when it |
790 | /// is known that the Error will always be a success value. E.g. |
791 | /// |
792 | /// @code{.cpp} |
793 | /// // foo only attempts the fallible operation if DoFallibleOperation is |
794 | /// // true. If DoFallibleOperation is false then foo always returns a Bar&. |
795 | /// Expected<Bar&> foo(bool DoFallibleOperation); |
796 | /// |
797 | /// Bar &X = cantFail(foo(false)); |
798 | /// @endcode |
799 | template <typename T> |
800 | T& cantFail(Expected<T&> ValOrErr, const char *Msg = nullptr) { |
801 | if (ValOrErr) |
802 | return *ValOrErr; |
803 | else { |
804 | if (!Msg) |
805 | Msg = "Failure value returned from cantFail wrapped call"; |
806 | #ifndef NDEBUG1 |
807 | std::string Str; |
808 | raw_string_ostream OS(Str); |
809 | auto E = ValOrErr.takeError(); |
810 | OS << Msg << "\n" << E; |
811 | Msg = OS.str().c_str(); |
812 | #endif |
813 | llvm_unreachable(Msg)__builtin_unreachable(); |
814 | } |
815 | } |
816 | |
817 | /// Helper for testing applicability of, and applying, handlers for |
818 | /// ErrorInfo types. |
819 | template <typename HandlerT> |
820 | class ErrorHandlerTraits |
821 | : public ErrorHandlerTraits<decltype( |
822 | &std::remove_reference<HandlerT>::type::operator())> {}; |
823 | |
824 | // Specialization functions of the form 'Error (const ErrT&)'. |
825 | template <typename ErrT> class ErrorHandlerTraits<Error (&)(ErrT &)> { |
826 | public: |
827 | static bool appliesTo(const ErrorInfoBase &E) { |
828 | return E.template isA<ErrT>(); |
829 | } |
830 | |
831 | template <typename HandlerT> |
832 | static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) { |
833 | assert(appliesTo(*E) && "Applying incorrect handler")((void)0); |
834 | return H(static_cast<ErrT &>(*E)); |
835 | } |
836 | }; |
837 | |
838 | // Specialization functions of the form 'void (const ErrT&)'. |
839 | template <typename ErrT> class ErrorHandlerTraits<void (&)(ErrT &)> { |
840 | public: |
841 | static bool appliesTo(const ErrorInfoBase &E) { |
842 | return E.template isA<ErrT>(); |
843 | } |
844 | |
845 | template <typename HandlerT> |
846 | static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) { |
847 | assert(appliesTo(*E) && "Applying incorrect handler")((void)0); |
848 | H(static_cast<ErrT &>(*E)); |
849 | return Error::success(); |
850 | } |
851 | }; |
852 | |
853 | /// Specialization for functions of the form 'Error (std::unique_ptr<ErrT>)'. |
854 | template <typename ErrT> |
855 | class ErrorHandlerTraits<Error (&)(std::unique_ptr<ErrT>)> { |
856 | public: |
857 | static bool appliesTo(const ErrorInfoBase &E) { |
858 | return E.template isA<ErrT>(); |
859 | } |
860 | |
861 | template <typename HandlerT> |
862 | static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) { |
863 | assert(appliesTo(*E) && "Applying incorrect handler")((void)0); |
864 | std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release())); |
865 | return H(std::move(SubE)); |
866 | } |
867 | }; |
868 | |
869 | /// Specialization for functions of the form 'void (std::unique_ptr<ErrT>)'. |
870 | template <typename ErrT> |
871 | class ErrorHandlerTraits<void (&)(std::unique_ptr<ErrT>)> { |
872 | public: |
873 | static bool appliesTo(const ErrorInfoBase &E) { |
874 | return E.template isA<ErrT>(); |
875 | } |
876 | |
877 | template <typename HandlerT> |
878 | static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) { |
879 | assert(appliesTo(*E) && "Applying incorrect handler")((void)0); |
880 | std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release())); |
881 | H(std::move(SubE)); |
882 | return Error::success(); |
883 | } |
884 | }; |
885 | |
886 | // Specialization for member functions of the form 'RetT (const ErrT&)'. |
887 | template <typename C, typename RetT, typename ErrT> |
888 | class ErrorHandlerTraits<RetT (C::*)(ErrT &)> |
889 | : public ErrorHandlerTraits<RetT (&)(ErrT &)> {}; |
890 | |
891 | // Specialization for member functions of the form 'RetT (const ErrT&) const'. |
892 | template <typename C, typename RetT, typename ErrT> |
893 | class ErrorHandlerTraits<RetT (C::*)(ErrT &) const> |
894 | : public ErrorHandlerTraits<RetT (&)(ErrT &)> {}; |
895 | |
896 | // Specialization for member functions of the form 'RetT (const ErrT&)'. |
897 | template <typename C, typename RetT, typename ErrT> |
898 | class ErrorHandlerTraits<RetT (C::*)(const ErrT &)> |
899 | : public ErrorHandlerTraits<RetT (&)(ErrT &)> {}; |
900 | |
901 | // Specialization for member functions of the form 'RetT (const ErrT&) const'. |
902 | template <typename C, typename RetT, typename ErrT> |
903 | class ErrorHandlerTraits<RetT (C::*)(const ErrT &) const> |
904 | : public ErrorHandlerTraits<RetT (&)(ErrT &)> {}; |
905 | |
906 | /// Specialization for member functions of the form |
907 | /// 'RetT (std::unique_ptr<ErrT>)'. |
908 | template <typename C, typename RetT, typename ErrT> |
909 | class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>)> |
910 | : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {}; |
911 | |
912 | /// Specialization for member functions of the form |
913 | /// 'RetT (std::unique_ptr<ErrT>) const'. |
914 | template <typename C, typename RetT, typename ErrT> |
915 | class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>) const> |
916 | : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {}; |
917 | |
918 | inline Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload) { |
919 | return Error(std::move(Payload)); |
920 | } |
921 | |
922 | template <typename HandlerT, typename... HandlerTs> |
923 | Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload, |
924 | HandlerT &&Handler, HandlerTs &&... Handlers) { |
925 | if (ErrorHandlerTraits<HandlerT>::appliesTo(*Payload)) |
926 | return ErrorHandlerTraits<HandlerT>::apply(std::forward<HandlerT>(Handler), |
927 | std::move(Payload)); |
928 | return handleErrorImpl(std::move(Payload), |
929 | std::forward<HandlerTs>(Handlers)...); |
930 | } |
931 | |
932 | /// Pass the ErrorInfo(s) contained in E to their respective handlers. Any |
933 | /// unhandled errors (or Errors returned by handlers) are re-concatenated and |
934 | /// returned. |
935 | /// Because this function returns an error, its result must also be checked |
936 | /// or returned. If you intend to handle all errors use handleAllErrors |
937 | /// (which returns void, and will abort() on unhandled errors) instead. |
938 | template <typename... HandlerTs> |
939 | Error handleErrors(Error E, HandlerTs &&... Hs) { |
940 | if (!E) |
941 | return Error::success(); |
942 | |
943 | std::unique_ptr<ErrorInfoBase> Payload = E.takePayload(); |
944 | |
945 | if (Payload->isA<ErrorList>()) { |
946 | ErrorList &List = static_cast<ErrorList &>(*Payload); |
947 | Error R; |
948 | for (auto &P : List.Payloads) |
949 | R = ErrorList::join( |
950 | std::move(R), |
951 | handleErrorImpl(std::move(P), std::forward<HandlerTs>(Hs)...)); |
952 | return R; |
953 | } |
954 | |
955 | return handleErrorImpl(std::move(Payload), std::forward<HandlerTs>(Hs)...); |
956 | } |
957 | |
958 | /// Behaves the same as handleErrors, except that by contract all errors |
959 | /// *must* be handled by the given handlers (i.e. there must be no remaining |
960 | /// errors after running the handlers, or llvm_unreachable is called). |
961 | template <typename... HandlerTs> |
962 | void handleAllErrors(Error E, HandlerTs &&... Handlers) { |
963 | cantFail(handleErrors(std::move(E), std::forward<HandlerTs>(Handlers)...)); |
964 | } |
965 | |
966 | /// Check that E is a non-error, then drop it. |
967 | /// If E is an error, llvm_unreachable will be called. |
968 | inline void handleAllErrors(Error E) { |
969 | cantFail(std::move(E)); |
970 | } |
971 | |
972 | /// Handle any errors (if present) in an Expected<T>, then try a recovery path. |
973 | /// |
974 | /// If the incoming value is a success value it is returned unmodified. If it |
975 | /// is a failure value then it the contained error is passed to handleErrors. |
976 | /// If handleErrors is able to handle the error then the RecoveryPath functor |
977 | /// is called to supply the final result. If handleErrors is not able to |
978 | /// handle all errors then the unhandled errors are returned. |
979 | /// |
980 | /// This utility enables the follow pattern: |
981 | /// |
982 | /// @code{.cpp} |
983 | /// enum FooStrategy { Aggressive, Conservative }; |
984 | /// Expected<Foo> foo(FooStrategy S); |
985 | /// |
986 | /// auto ResultOrErr = |
987 | /// handleExpected( |
988 | /// foo(Aggressive), |
989 | /// []() { return foo(Conservative); }, |
990 | /// [](AggressiveStrategyError&) { |
991 | /// // Implicitly conusme this - we'll recover by using a conservative |
992 | /// // strategy. |
993 | /// }); |
994 | /// |
995 | /// @endcode |
996 | template <typename T, typename RecoveryFtor, typename... HandlerTs> |
997 | Expected<T> handleExpected(Expected<T> ValOrErr, RecoveryFtor &&RecoveryPath, |
998 | HandlerTs &&... Handlers) { |
999 | if (ValOrErr) |
1000 | return ValOrErr; |
1001 | |
1002 | if (auto Err = handleErrors(ValOrErr.takeError(), |
1003 | std::forward<HandlerTs>(Handlers)...)) |
1004 | return std::move(Err); |
1005 | |
1006 | return RecoveryPath(); |
1007 | } |
1008 | |
1009 | /// Log all errors (if any) in E to OS. If there are any errors, ErrorBanner |
1010 | /// will be printed before the first one is logged. A newline will be printed |
1011 | /// after each error. |
1012 | /// |
1013 | /// This function is compatible with the helpers from Support/WithColor.h. You |
1014 | /// can pass any of them as the OS. Please consider using them instead of |
1015 | /// including 'error: ' in the ErrorBanner. |
1016 | /// |
1017 | /// This is useful in the base level of your program to allow clean termination |
1018 | /// (allowing clean deallocation of resources, etc.), while reporting error |
1019 | /// information to the user. |
1020 | void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner = {}); |
1021 | |
1022 | /// Write all error messages (if any) in E to a string. The newline character |
1023 | /// is used to separate error messages. |
1024 | inline std::string toString(Error E) { |
1025 | SmallVector<std::string, 2> Errors; |
1026 | handleAllErrors(std::move(E), [&Errors](const ErrorInfoBase &EI) { |
1027 | Errors.push_back(EI.message()); |
1028 | }); |
1029 | return join(Errors.begin(), Errors.end(), "\n"); |
1030 | } |
1031 | |
1032 | /// Consume a Error without doing anything. This method should be used |
1033 | /// only where an error can be considered a reasonable and expected return |
1034 | /// value. |
1035 | /// |
1036 | /// Uses of this method are potentially indicative of design problems: If it's |
1037 | /// legitimate to do nothing while processing an "error", the error-producer |
1038 | /// might be more clearly refactored to return an Optional<T>. |
1039 | inline void consumeError(Error Err) { |
1040 | handleAllErrors(std::move(Err), [](const ErrorInfoBase &) {}); |
1041 | } |
1042 | |
1043 | /// Convert an Expected to an Optional without doing anything. This method |
1044 | /// should be used only where an error can be considered a reasonable and |
1045 | /// expected return value. |
1046 | /// |
1047 | /// Uses of this method are potentially indicative of problems: perhaps the |
1048 | /// error should be propagated further, or the error-producer should just |
1049 | /// return an Optional in the first place. |
1050 | template <typename T> Optional<T> expectedToOptional(Expected<T> &&E) { |
1051 | if (E) |
1052 | return std::move(*E); |
1053 | consumeError(E.takeError()); |
1054 | return None; |
1055 | } |
1056 | |
1057 | /// Helper for converting an Error to a bool. |
1058 | /// |
1059 | /// This method returns true if Err is in an error state, or false if it is |
1060 | /// in a success state. Puts Err in a checked state in both cases (unlike |
1061 | /// Error::operator bool(), which only does this for success states). |
1062 | inline bool errorToBool(Error Err) { |
1063 | bool IsError = static_cast<bool>(Err); |
1064 | if (IsError) |
1065 | consumeError(std::move(Err)); |
1066 | return IsError; |
1067 | } |
1068 | |
1069 | /// Helper for Errors used as out-parameters. |
1070 | /// |
1071 | /// This helper is for use with the Error-as-out-parameter idiom, where an error |
1072 | /// is passed to a function or method by reference, rather than being returned. |
1073 | /// In such cases it is helpful to set the checked bit on entry to the function |
1074 | /// so that the error can be written to (unchecked Errors abort on assignment) |
1075 | /// and clear the checked bit on exit so that clients cannot accidentally forget |
1076 | /// to check the result. This helper performs these actions automatically using |
1077 | /// RAII: |
1078 | /// |
1079 | /// @code{.cpp} |
1080 | /// Result foo(Error &Err) { |
1081 | /// ErrorAsOutParameter ErrAsOutParam(&Err); // 'Checked' flag set |
1082 | /// // <body of foo> |
1083 | /// // <- 'Checked' flag auto-cleared when ErrAsOutParam is destructed. |
1084 | /// } |
1085 | /// @endcode |
1086 | /// |
1087 | /// ErrorAsOutParameter takes an Error* rather than Error& so that it can be |
1088 | /// used with optional Errors (Error pointers that are allowed to be null). If |
1089 | /// ErrorAsOutParameter took an Error reference, an instance would have to be |
1090 | /// created inside every condition that verified that Error was non-null. By |
1091 | /// taking an Error pointer we can just create one instance at the top of the |
1092 | /// function. |
1093 | class ErrorAsOutParameter { |
1094 | public: |
1095 | ErrorAsOutParameter(Error *Err) : Err(Err) { |
1096 | // Raise the checked bit if Err is success. |
1097 | if (Err) |
1098 | (void)!!*Err; |
1099 | } |
1100 | |
1101 | ~ErrorAsOutParameter() { |
1102 | // Clear the checked bit. |
1103 | if (Err && !*Err) |
1104 | *Err = Error::success(); |
1105 | } |
1106 | |
1107 | private: |
1108 | Error *Err; |
1109 | }; |
1110 | |
1111 | /// Helper for Expected<T>s used as out-parameters. |
1112 | /// |
1113 | /// See ErrorAsOutParameter. |
1114 | template <typename T> |
1115 | class ExpectedAsOutParameter { |
1116 | public: |
1117 | ExpectedAsOutParameter(Expected<T> *ValOrErr) |
1118 | : ValOrErr(ValOrErr) { |
1119 | if (ValOrErr) |
1120 | (void)!!*ValOrErr; |
1121 | } |
1122 | |
1123 | ~ExpectedAsOutParameter() { |
1124 | if (ValOrErr) |
1125 | ValOrErr->setUnchecked(); |
1126 | } |
1127 | |
1128 | private: |
1129 | Expected<T> *ValOrErr; |
1130 | }; |
1131 | |
1132 | /// This class wraps a std::error_code in a Error. |
1133 | /// |
1134 | /// This is useful if you're writing an interface that returns a Error |
1135 | /// (or Expected) and you want to call code that still returns |
1136 | /// std::error_codes. |
1137 | class ECError : public ErrorInfo<ECError> { |
1138 | friend Error errorCodeToError(std::error_code); |
1139 | |
1140 | virtual void anchor() override; |
1141 | |
1142 | public: |
1143 | void setErrorCode(std::error_code EC) { this->EC = EC; } |
1144 | std::error_code convertToErrorCode() const override { return EC; } |
1145 | void log(raw_ostream &OS) const override { OS << EC.message(); } |
1146 | |
1147 | // Used by ErrorInfo::classID. |
1148 | static char ID; |
1149 | |
1150 | protected: |
1151 | ECError() = default; |
1152 | ECError(std::error_code EC) : EC(EC) {} |
1153 | |
1154 | std::error_code EC; |
1155 | }; |
1156 | |
1157 | /// The value returned by this function can be returned from convertToErrorCode |
1158 | /// for Error values where no sensible translation to std::error_code exists. |
1159 | /// It should only be used in this situation, and should never be used where a |
1160 | /// sensible conversion to std::error_code is available, as attempts to convert |
1161 | /// to/from this error will result in a fatal error. (i.e. it is a programmatic |
1162 | ///error to try to convert such a value). |
1163 | std::error_code inconvertibleErrorCode(); |
1164 | |
1165 | /// Helper for converting an std::error_code to a Error. |
1166 | Error errorCodeToError(std::error_code EC); |
1167 | |
1168 | /// Helper for converting an ECError to a std::error_code. |
1169 | /// |
1170 | /// This method requires that Err be Error() or an ECError, otherwise it |
1171 | /// will trigger a call to abort(). |
1172 | std::error_code errorToErrorCode(Error Err); |
1173 | |
1174 | /// Convert an ErrorOr<T> to an Expected<T>. |
1175 | template <typename T> Expected<T> errorOrToExpected(ErrorOr<T> &&EO) { |
1176 | if (auto EC = EO.getError()) |
1177 | return errorCodeToError(EC); |
1178 | return std::move(*EO); |
1179 | } |
1180 | |
1181 | /// Convert an Expected<T> to an ErrorOr<T>. |
1182 | template <typename T> ErrorOr<T> expectedToErrorOr(Expected<T> &&E) { |
1183 | if (auto Err = E.takeError()) |
1184 | return errorToErrorCode(std::move(Err)); |
1185 | return std::move(*E); |
1186 | } |
1187 | |
1188 | /// This class wraps a string in an Error. |
1189 | /// |
1190 | /// StringError is useful in cases where the client is not expected to be able |
1191 | /// to consume the specific error message programmatically (for example, if the |
1192 | /// error message is to be presented to the user). |
1193 | /// |
1194 | /// StringError can also be used when additional information is to be printed |
1195 | /// along with a error_code message. Depending on the constructor called, this |
1196 | /// class can either display: |
1197 | /// 1. the error_code message (ECError behavior) |
1198 | /// 2. a string |
1199 | /// 3. the error_code message and a string |
1200 | /// |
1201 | /// These behaviors are useful when subtyping is required; for example, when a |
1202 | /// specific library needs an explicit error type. In the example below, |
1203 | /// PDBError is derived from StringError: |
1204 | /// |
1205 | /// @code{.cpp} |
1206 | /// Expected<int> foo() { |
1207 | /// return llvm::make_error<PDBError>(pdb_error_code::dia_failed_loading, |
1208 | /// "Additional information"); |
1209 | /// } |
1210 | /// @endcode |
1211 | /// |
1212 | class StringError : public ErrorInfo<StringError> { |
1213 | public: |
1214 | static char ID; |
1215 | |
1216 | // Prints EC + S and converts to EC |
1217 | StringError(std::error_code EC, const Twine &S = Twine()); |
1218 | |
1219 | // Prints S and converts to EC |
1220 | StringError(const Twine &S, std::error_code EC); |
1221 | |
1222 | void log(raw_ostream &OS) const override; |
1223 | std::error_code convertToErrorCode() const override; |
1224 | |
1225 | const std::string &getMessage() const { return Msg; } |
1226 | |
1227 | private: |
1228 | std::string Msg; |
1229 | std::error_code EC; |
1230 | const bool PrintMsgOnly = false; |
1231 | }; |
1232 | |
1233 | /// Create formatted StringError object. |
1234 | template <typename... Ts> |
1235 | inline Error createStringError(std::error_code EC, char const *Fmt, |
1236 | const Ts &... Vals) { |
1237 | std::string Buffer; |
1238 | raw_string_ostream Stream(Buffer); |
1239 | Stream << format(Fmt, Vals...); |
1240 | return make_error<StringError>(Stream.str(), EC); |
1241 | } |
1242 | |
1243 | Error createStringError(std::error_code EC, char const *Msg); |
1244 | |
1245 | inline Error createStringError(std::error_code EC, const Twine &S) { |
1246 | return createStringError(EC, S.str().c_str()); |
1247 | } |
1248 | |
1249 | template <typename... Ts> |
1250 | inline Error createStringError(std::errc EC, char const *Fmt, |
1251 | const Ts &... Vals) { |
1252 | return createStringError(std::make_error_code(EC), Fmt, Vals...); |
1253 | } |
1254 | |
1255 | /// This class wraps a filename and another Error. |
1256 | /// |
1257 | /// In some cases, an error needs to live along a 'source' name, in order to |
1258 | /// show more detailed information to the user. |
1259 | class FileError final : public ErrorInfo<FileError> { |
1260 | |
1261 | friend Error createFileError(const Twine &, Error); |
1262 | friend Error createFileError(const Twine &, size_t, Error); |
1263 | |
1264 | public: |
1265 | void log(raw_ostream &OS) const override { |
1266 | assert(Err && !FileName.empty() && "Trying to log after takeError().")((void)0); |
1267 | OS << "'" << FileName << "': "; |
1268 | if (Line.hasValue()) |
1269 | OS << "line " << Line.getValue() << ": "; |
1270 | Err->log(OS); |
1271 | } |
1272 | |
1273 | StringRef getFileName() { return FileName; } |
1274 | |
1275 | Error takeError() { return Error(std::move(Err)); } |
1276 | |
1277 | std::error_code convertToErrorCode() const override; |
1278 | |
1279 | // Used by ErrorInfo::classID. |
1280 | static char ID; |
1281 | |
1282 | private: |
1283 | FileError(const Twine &F, Optional<size_t> LineNum, |
1284 | std::unique_ptr<ErrorInfoBase> E) { |
1285 | assert(E && "Cannot create FileError from Error success value.")((void)0); |
1286 | assert(!F.isTriviallyEmpty() &&((void)0) |
1287 | "The file name provided to FileError must not be empty.")((void)0); |
1288 | FileName = F.str(); |
1289 | Err = std::move(E); |
1290 | Line = std::move(LineNum); |
1291 | } |
1292 | |
1293 | static Error build(const Twine &F, Optional<size_t> Line, Error E) { |
1294 | std::unique_ptr<ErrorInfoBase> Payload; |
1295 | handleAllErrors(std::move(E), |
1296 | [&](std::unique_ptr<ErrorInfoBase> EIB) -> Error { |
1297 | Payload = std::move(EIB); |
1298 | return Error::success(); |
1299 | }); |
1300 | return Error( |
1301 | std::unique_ptr<FileError>(new FileError(F, Line, std::move(Payload)))); |
1302 | } |
1303 | |
1304 | std::string FileName; |
1305 | Optional<size_t> Line; |
1306 | std::unique_ptr<ErrorInfoBase> Err; |
1307 | }; |
1308 | |
1309 | /// Concatenate a source file path and/or name with an Error. The resulting |
1310 | /// Error is unchecked. |
1311 | inline Error createFileError(const Twine &F, Error E) { |
1312 | return FileError::build(F, Optional<size_t>(), std::move(E)); |
1313 | } |
1314 | |
1315 | /// Concatenate a source file path and/or name with line number and an Error. |
1316 | /// The resulting Error is unchecked. |
1317 | inline Error createFileError(const Twine &F, size_t Line, Error E) { |
1318 | return FileError::build(F, Optional<size_t>(Line), std::move(E)); |
1319 | } |
1320 | |
1321 | /// Concatenate a source file path and/or name with a std::error_code |
1322 | /// to form an Error object. |
1323 | inline Error createFileError(const Twine &F, std::error_code EC) { |
1324 | return createFileError(F, errorCodeToError(EC)); |
1325 | } |
1326 | |
1327 | /// Concatenate a source file path and/or name with line number and |
1328 | /// std::error_code to form an Error object. |
1329 | inline Error createFileError(const Twine &F, size_t Line, std::error_code EC) { |
1330 | return createFileError(F, Line, errorCodeToError(EC)); |
1331 | } |
1332 | |
1333 | Error createFileError(const Twine &F, ErrorSuccess) = delete; |
1334 | |
1335 | /// Helper for check-and-exit error handling. |
1336 | /// |
1337 | /// For tool use only. NOT FOR USE IN LIBRARY CODE. |
1338 | /// |
1339 | class ExitOnError { |
1340 | public: |
1341 | /// Create an error on exit helper. |
1342 | ExitOnError(std::string Banner = "", int DefaultErrorExitCode = 1) |
1343 | : Banner(std::move(Banner)), |
1344 | GetExitCode([=](const Error &) { return DefaultErrorExitCode; }) {} |
1345 | |
1346 | /// Set the banner string for any errors caught by operator(). |
1347 | void setBanner(std::string Banner) { this->Banner = std::move(Banner); } |
1348 | |
1349 | /// Set the exit-code mapper function. |
1350 | void setExitCodeMapper(std::function<int(const Error &)> GetExitCode) { |
1351 | this->GetExitCode = std::move(GetExitCode); |
1352 | } |
1353 | |
1354 | /// Check Err. If it's in a failure state log the error(s) and exit. |
1355 | void operator()(Error Err) const { checkError(std::move(Err)); } |
1356 | |
1357 | /// Check E. If it's in a success state then return the contained value. If |
1358 | /// it's in a failure state log the error(s) and exit. |
1359 | template <typename T> T operator()(Expected<T> &&E) const { |
1360 | checkError(E.takeError()); |
1361 | return std::move(*E); |
1362 | } |
1363 | |
1364 | /// Check E. If it's in a success state then return the contained reference. If |
1365 | /// it's in a failure state log the error(s) and exit. |
1366 | template <typename T> T& operator()(Expected<T&> &&E) const { |
1367 | checkError(E.takeError()); |
1368 | return *E; |
1369 | } |
1370 | |
1371 | private: |
1372 | void checkError(Error Err) const { |
1373 | if (Err) { |
1374 | int ExitCode = GetExitCode(Err); |
1375 | logAllUnhandledErrors(std::move(Err), errs(), Banner); |
1376 | exit(ExitCode); |
1377 | } |
1378 | } |
1379 | |
1380 | std::string Banner; |
1381 | std::function<int(const Error &)> GetExitCode; |
1382 | }; |
1383 | |
1384 | /// Conversion from Error to LLVMErrorRef for C error bindings. |
1385 | inline LLVMErrorRef wrap(Error Err) { |
1386 | return reinterpret_cast<LLVMErrorRef>(Err.takePayload().release()); |
1387 | } |
1388 | |
1389 | /// Conversion from LLVMErrorRef to Error for C error bindings. |
1390 | inline Error unwrap(LLVMErrorRef ErrRef) { |
1391 | return Error(std::unique_ptr<ErrorInfoBase>( |
1392 | reinterpret_cast<ErrorInfoBase *>(ErrRef))); |
1393 | } |
1394 | |
1395 | } // end namespace llvm |
1396 | |
1397 | #endif // LLVM_SUPPORT_ERROR_H |