| File: | src/gnu/usr.bin/clang/libLLVM/../../../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 |