Bug Summary

File:llvm/lib/LTO/LTOBackend.cpp
Warning:line 249, column 40
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name LTOBackend.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/lib/LTO -resource-dir /usr/lib/llvm-14/lib/clang/14.0.0 -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/lib/LTO -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/lib/LTO -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/include -D NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-14/lib/clang/14.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/lib/LTO -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e=. -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2021-09-04-040900-46481-1 -x c++ /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/lib/LTO/LTOBackend.cpp

/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/lib/LTO/LTOBackend.cpp

1//===-LTOBackend.cpp - LLVM Link Time Optimizer Backend -------------------===//
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 implements the "backend" phase of LTO, i.e. it performs
10// optimization and code generation on a loaded module. It is generally used
11// internally by the LTO class but can also be used independently, for example
12// to implement a standalone ThinLTO backend.
13//
14//===----------------------------------------------------------------------===//
15
16#include "llvm/LTO/LTOBackend.h"
17#include "llvm/Analysis/AliasAnalysis.h"
18#include "llvm/Analysis/CGSCCPassManager.h"
19#include "llvm/Analysis/ModuleSummaryAnalysis.h"
20#include "llvm/Analysis/TargetLibraryInfo.h"
21#include "llvm/Analysis/TargetTransformInfo.h"
22#include "llvm/Bitcode/BitcodeReader.h"
23#include "llvm/Bitcode/BitcodeWriter.h"
24#include "llvm/IR/LLVMRemarkStreamer.h"
25#include "llvm/IR/LegacyPassManager.h"
26#include "llvm/IR/PassManager.h"
27#include "llvm/IR/Verifier.h"
28#include "llvm/LTO/LTO.h"
29#include "llvm/MC/SubtargetFeature.h"
30#include "llvm/Object/ModuleSymbolTable.h"
31#include "llvm/Passes/PassBuilder.h"
32#include "llvm/Passes/PassPlugin.h"
33#include "llvm/Passes/StandardInstrumentations.h"
34#include "llvm/Support/Error.h"
35#include "llvm/Support/FileSystem.h"
36#include "llvm/Support/MemoryBuffer.h"
37#include "llvm/Support/Path.h"
38#include "llvm/Support/Program.h"
39#include "llvm/Support/SmallVectorMemoryBuffer.h"
40#include "llvm/Support/TargetRegistry.h"
41#include "llvm/Support/ThreadPool.h"
42#include "llvm/Support/raw_ostream.h"
43#include "llvm/Target/TargetMachine.h"
44#include "llvm/Transforms/IPO.h"
45#include "llvm/Transforms/IPO/PassManagerBuilder.h"
46#include "llvm/Transforms/Scalar/LoopPassManager.h"
47#include "llvm/Transforms/Utils/FunctionImportUtils.h"
48#include "llvm/Transforms/Utils/SplitModule.h"
49
50using namespace llvm;
51using namespace lto;
52
53#define DEBUG_TYPE"lto-backend" "lto-backend"
54
55enum class LTOBitcodeEmbedding {
56 DoNotEmbed = 0,
57 EmbedOptimized = 1,
58 EmbedPostMergePreOptimized = 2
59};
60
61static cl::opt<LTOBitcodeEmbedding> EmbedBitcode(
62 "lto-embed-bitcode", cl::init(LTOBitcodeEmbedding::DoNotEmbed),
63 cl::values(clEnumValN(LTOBitcodeEmbedding::DoNotEmbed, "none",llvm::cl::OptionEnumValue { "none", int(LTOBitcodeEmbedding::
DoNotEmbed), "Do not embed" }
64 "Do not embed")llvm::cl::OptionEnumValue { "none", int(LTOBitcodeEmbedding::
DoNotEmbed), "Do not embed" }
,
65 clEnumValN(LTOBitcodeEmbedding::EmbedOptimized, "optimized",llvm::cl::OptionEnumValue { "optimized", int(LTOBitcodeEmbedding
::EmbedOptimized), "Embed after all optimization passes" }
66 "Embed after all optimization passes")llvm::cl::OptionEnumValue { "optimized", int(LTOBitcodeEmbedding
::EmbedOptimized), "Embed after all optimization passes" }
,
67 clEnumValN(LTOBitcodeEmbedding::EmbedPostMergePreOptimized,llvm::cl::OptionEnumValue { "post-merge-pre-opt", int(LTOBitcodeEmbedding
::EmbedPostMergePreOptimized), "Embed post merge, but before optimizations"
}
68 "post-merge-pre-opt",llvm::cl::OptionEnumValue { "post-merge-pre-opt", int(LTOBitcodeEmbedding
::EmbedPostMergePreOptimized), "Embed post merge, but before optimizations"
}
69 "Embed post merge, but before optimizations")llvm::cl::OptionEnumValue { "post-merge-pre-opt", int(LTOBitcodeEmbedding
::EmbedPostMergePreOptimized), "Embed post merge, but before optimizations"
}
),
70 cl::desc("Embed LLVM bitcode in object files produced by LTO"));
71
72static cl::opt<bool> ThinLTOAssumeMerged(
73 "thinlto-assume-merged", cl::init(false),
74 cl::desc("Assume the input has already undergone ThinLTO function "
75 "importing and the other pre-optimization pipeline changes."));
76
77namespace llvm {
78extern cl::opt<bool> NoPGOWarnMismatch;
79}
80
81[[noreturn]] static void reportOpenError(StringRef Path, Twine Msg) {
82 errs() << "failed to open " << Path << ": " << Msg << '\n';
83 errs().flush();
84 exit(1);
85}
86
87Error Config::addSaveTemps(std::string OutputFileName,
88 bool UseInputModulePath) {
89 ShouldDiscardValueNames = false;
90
91 std::error_code EC;
92 ResolutionFile =
93 std::make_unique<raw_fd_ostream>(OutputFileName + "resolution.txt", EC,
94 sys::fs::OpenFlags::OF_TextWithCRLF);
95 if (EC) {
96 ResolutionFile.reset();
97 return errorCodeToError(EC);
98 }
99
100 auto setHook = [&](std::string PathSuffix, ModuleHookFn &Hook) {
101 // Keep track of the hook provided by the linker, which also needs to run.
102 ModuleHookFn LinkerHook = Hook;
103 Hook = [=](unsigned Task, const Module &M) {
104 // If the linker's hook returned false, we need to pass that result
105 // through.
106 if (LinkerHook && !LinkerHook(Task, M))
107 return false;
108
109 std::string PathPrefix;
110 // If this is the combined module (not a ThinLTO backend compile) or the
111 // user hasn't requested using the input module's path, emit to a file
112 // named from the provided OutputFileName with the Task ID appended.
113 if (M.getModuleIdentifier() == "ld-temp.o" || !UseInputModulePath) {
114 PathPrefix = OutputFileName;
115 if (Task != (unsigned)-1)
116 PathPrefix += utostr(Task) + ".";
117 } else
118 PathPrefix = M.getModuleIdentifier() + ".";
119 std::string Path = PathPrefix + PathSuffix + ".bc";
120 std::error_code EC;
121 raw_fd_ostream OS(Path, EC, sys::fs::OpenFlags::OF_None);
122 // Because -save-temps is a debugging feature, we report the error
123 // directly and exit.
124 if (EC)
125 reportOpenError(Path, EC.message());
126 WriteBitcodeToFile(M, OS, /*ShouldPreserveUseListOrder=*/false);
127 return true;
128 };
129 };
130
131 setHook("0.preopt", PreOptModuleHook);
132 setHook("1.promote", PostPromoteModuleHook);
133 setHook("2.internalize", PostInternalizeModuleHook);
134 setHook("3.import", PostImportModuleHook);
135 setHook("4.opt", PostOptModuleHook);
136 setHook("5.precodegen", PreCodeGenModuleHook);
137
138 CombinedIndexHook =
139 [=](const ModuleSummaryIndex &Index,
140 const DenseSet<GlobalValue::GUID> &GUIDPreservedSymbols) {
141 std::string Path = OutputFileName + "index.bc";
142 std::error_code EC;
143 raw_fd_ostream OS(Path, EC, sys::fs::OpenFlags::OF_None);
144 // Because -save-temps is a debugging feature, we report the error
145 // directly and exit.
146 if (EC)
147 reportOpenError(Path, EC.message());
148 WriteIndexToFile(Index, OS);
149
150 Path = OutputFileName + "index.dot";
151 raw_fd_ostream OSDot(Path, EC, sys::fs::OpenFlags::OF_None);
152 if (EC)
153 reportOpenError(Path, EC.message());
154 Index.exportToDot(OSDot, GUIDPreservedSymbols);
155 return true;
156 };
157
158 return Error::success();
159}
160
161#define HANDLE_EXTENSION(Ext) \
162 llvm::PassPluginLibraryInfo get##Ext##PluginInfo();
163#include "llvm/Support/Extension.def"
164
165static void RegisterPassPlugins(ArrayRef<std::string> PassPlugins,
166 PassBuilder &PB) {
167#define HANDLE_EXTENSION(Ext) \
168 get##Ext##PluginInfo().RegisterPassBuilderCallbacks(PB);
169#include "llvm/Support/Extension.def"
170
171 // Load requested pass plugins and let them register pass builder callbacks
172 for (auto &PluginFN : PassPlugins) {
173 auto PassPlugin = PassPlugin::Load(PluginFN);
174 if (!PassPlugin) {
175 errs() << "Failed to load passes from '" << PluginFN
176 << "'. Request ignored.\n";
177 continue;
178 }
179
180 PassPlugin->registerPassBuilderCallbacks(PB);
181 }
182}
183
184static std::unique_ptr<TargetMachine>
185createTargetMachine(const Config &Conf, const Target *TheTarget, Module &M) {
186 StringRef TheTriple = M.getTargetTriple();
187 SubtargetFeatures Features;
188 Features.getDefaultSubtargetFeatures(Triple(TheTriple));
189 for (const std::string &A : Conf.MAttrs)
190 Features.AddFeature(A);
191
192 Optional<Reloc::Model> RelocModel = None;
193 if (Conf.RelocModel)
194 RelocModel = *Conf.RelocModel;
195 else if (M.getModuleFlag("PIC Level"))
196 RelocModel =
197 M.getPICLevel() == PICLevel::NotPIC ? Reloc::Static : Reloc::PIC_;
198
199 Optional<CodeModel::Model> CodeModel;
200 if (Conf.CodeModel)
201 CodeModel = *Conf.CodeModel;
202 else
203 CodeModel = M.getCodeModel();
204
205 std::unique_ptr<TargetMachine> TM(TheTarget->createTargetMachine(
206 TheTriple, Conf.CPU, Features.getString(), Conf.Options, RelocModel,
207 CodeModel, Conf.CGOptLevel));
208 assert(TM && "Failed to create target machine")(static_cast<void> (0));
209 return TM;
210}
211
212static void runNewPMPasses(const Config &Conf, Module &Mod, TargetMachine *TM,
213 unsigned OptLevel, bool IsThinLTO,
214 ModuleSummaryIndex *ExportSummary,
215 const ModuleSummaryIndex *ImportSummary) {
216 Optional<PGOOptions> PGOOpt;
217 if (!Conf.SampleProfile.empty())
14
Assuming the condition is false
15
Taking false branch
218 PGOOpt = PGOOptions(Conf.SampleProfile, "", Conf.ProfileRemapping,
219 PGOOptions::SampleUse, PGOOptions::NoCSAction, true);
220 else if (Conf.RunCSIRInstr) {
16
Assuming field 'RunCSIRInstr' is false
17
Taking false branch
221 PGOOpt = PGOOptions("", Conf.CSIRProfile, Conf.ProfileRemapping,
222 PGOOptions::IRUse, PGOOptions::CSIRInstr,
223 Conf.AddFSDiscriminator);
224 } else if (!Conf.CSIRProfile.empty()) {
18
Assuming the condition is false
19
Taking false branch
225 PGOOpt = PGOOptions(Conf.CSIRProfile, "", Conf.ProfileRemapping,
226 PGOOptions::IRUse, PGOOptions::CSIRUse,
227 Conf.AddFSDiscriminator);
228 NoPGOWarnMismatch = !Conf.PGOWarnMismatch;
229 } else if (Conf.AddFSDiscriminator) {
20
Assuming field 'AddFSDiscriminator' is false
21
Taking false branch
230 PGOOpt = PGOOptions("", "", "", PGOOptions::NoAction,
231 PGOOptions::NoCSAction, true);
232 }
233 if (TM)
22
Assuming 'TM' is null
23
Taking false branch
234 TM->setPGOOption(PGOOpt);
235
236 LoopAnalysisManager LAM;
237 FunctionAnalysisManager FAM;
238 CGSCCAnalysisManager CGAM;
239 ModuleAnalysisManager MAM;
240
241 PassInstrumentationCallbacks PIC;
242 StandardInstrumentations SI(Conf.DebugPassManager);
243 SI.registerCallbacks(PIC, &FAM);
244 PassBuilder PB(TM, Conf.PTO, PGOOpt, &PIC);
245
246 RegisterPassPlugins(Conf.PassPlugins, PB);
247
248 std::unique_ptr<TargetLibraryInfoImpl> TLII(
249 new TargetLibraryInfoImpl(Triple(TM->getTargetTriple())));
24
Called C++ object pointer is null
250 if (Conf.Freestanding)
251 TLII->disableAllFunctions();
252 FAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); });
253
254 AAManager AA;
255 // Parse a custom AA pipeline if asked to.
256 if (!Conf.AAPipeline.empty()) {
257 if (auto Err = PB.parseAAPipeline(AA, Conf.AAPipeline)) {
258 report_fatal_error("unable to parse AA pipeline description '" +
259 Conf.AAPipeline + "': " + toString(std::move(Err)));
260 }
261 } else {
262 AA = PB.buildDefaultAAPipeline();
263 }
264 // Register the AA manager first so that our version is the one used.
265 FAM.registerPass([&] { return std::move(AA); });
266
267 // Register all the basic analyses with the managers.
268 PB.registerModuleAnalyses(MAM);
269 PB.registerCGSCCAnalyses(CGAM);
270 PB.registerFunctionAnalyses(FAM);
271 PB.registerLoopAnalyses(LAM);
272 PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
273
274 ModulePassManager MPM;
275
276 if (!Conf.DisableVerify)
277 MPM.addPass(VerifierPass());
278
279 OptimizationLevel OL;
280
281 switch (OptLevel) {
282 default:
283 llvm_unreachable("Invalid optimization level")__builtin_unreachable();
284 case 0:
285 OL = OptimizationLevel::O0;
286 break;
287 case 1:
288 OL = OptimizationLevel::O1;
289 break;
290 case 2:
291 OL = OptimizationLevel::O2;
292 break;
293 case 3:
294 OL = OptimizationLevel::O3;
295 break;
296 }
297
298 // Parse a custom pipeline if asked to.
299 if (!Conf.OptPipeline.empty()) {
300 if (auto Err = PB.parsePassPipeline(MPM, Conf.OptPipeline)) {
301 report_fatal_error("unable to parse pass pipeline description '" +
302 Conf.OptPipeline + "': " + toString(std::move(Err)));
303 }
304 } else if (IsThinLTO) {
305 MPM.addPass(PB.buildThinLTODefaultPipeline(OL, ImportSummary));
306 } else {
307 MPM.addPass(PB.buildLTODefaultPipeline(OL, ExportSummary));
308 }
309
310 if (!Conf.DisableVerify)
311 MPM.addPass(VerifierPass());
312
313 MPM.run(Mod, MAM);
314}
315
316static void runOldPMPasses(const Config &Conf, Module &Mod, TargetMachine *TM,
317 bool IsThinLTO, ModuleSummaryIndex *ExportSummary,
318 const ModuleSummaryIndex *ImportSummary) {
319 legacy::PassManager passes;
320 passes.add(createTargetTransformInfoWrapperPass(TM->getTargetIRAnalysis()));
321
322 PassManagerBuilder PMB;
323 PMB.LibraryInfo = new TargetLibraryInfoImpl(Triple(TM->getTargetTriple()));
324 if (Conf.Freestanding)
325 PMB.LibraryInfo->disableAllFunctions();
326 PMB.Inliner = createFunctionInliningPass();
327 PMB.ExportSummary = ExportSummary;
328 PMB.ImportSummary = ImportSummary;
329 // Unconditionally verify input since it is not verified before this
330 // point and has unknown origin.
331 PMB.VerifyInput = true;
332 PMB.VerifyOutput = !Conf.DisableVerify;
333 PMB.LoopVectorize = true;
334 PMB.SLPVectorize = true;
335 PMB.OptLevel = Conf.OptLevel;
336 PMB.PGOSampleUse = Conf.SampleProfile;
337 PMB.EnablePGOCSInstrGen = Conf.RunCSIRInstr;
338 if (!Conf.RunCSIRInstr && !Conf.CSIRProfile.empty()) {
339 PMB.EnablePGOCSInstrUse = true;
340 PMB.PGOInstrUse = Conf.CSIRProfile;
341 }
342 if (IsThinLTO)
343 PMB.populateThinLTOPassManager(passes);
344 else
345 PMB.populateLTOPassManager(passes);
346 passes.run(Mod);
347}
348
349bool lto::opt(const Config &Conf, TargetMachine *TM, unsigned Task, Module &Mod,
350 bool IsThinLTO, ModuleSummaryIndex *ExportSummary,
351 const ModuleSummaryIndex *ImportSummary,
352 const std::vector<uint8_t> &CmdArgs) {
353 if (EmbedBitcode == LTOBitcodeEmbedding::EmbedPostMergePreOptimized) {
10
Assuming the condition is false
354 // FIXME: the motivation for capturing post-merge bitcode and command line
355 // is replicating the compilation environment from bitcode, without needing
356 // to understand the dependencies (the functions to be imported). This
357 // assumes a clang - based invocation, case in which we have the command
358 // line.
359 // It's not very clear how the above motivation would map in the
360 // linker-based case, so we currently don't plumb the command line args in
361 // that case.
362 if (CmdArgs.empty())
363 LLVM_DEBUG(do { } while (false)
364 dbgs() << "Post-(Thin)LTO merge bitcode embedding was requested, but "do { } while (false)
365 "command line arguments are not available")do { } while (false);
366 llvm::EmbedBitcodeInModule(Mod, llvm::MemoryBufferRef(),
367 /*EmbedBitcode*/ true, /*EmbedCmdline*/ true,
368 /*Cmdline*/ CmdArgs);
369 }
370 // FIXME: Plumb the combined index into the new pass manager.
371 if (Conf.UseNewPM || !Conf.OptPipeline.empty()) {
11
Assuming field 'UseNewPM' is true
372 runNewPMPasses(Conf, Mod, TM, Conf.OptLevel, IsThinLTO, ExportSummary,
12
Passing value via 3rd parameter 'TM'
13
Calling 'runNewPMPasses'
373 ImportSummary);
374 } else {
375 runOldPMPasses(Conf, Mod, TM, IsThinLTO, ExportSummary, ImportSummary);
376 }
377 return !Conf.PostOptModuleHook || Conf.PostOptModuleHook(Task, Mod);
378}
379
380static void codegen(const Config &Conf, TargetMachine *TM,
381 AddStreamFn AddStream, unsigned Task, Module &Mod,
382 const ModuleSummaryIndex &CombinedIndex) {
383 if (Conf.PreCodeGenModuleHook && !Conf.PreCodeGenModuleHook(Task, Mod))
384 return;
385
386 if (EmbedBitcode == LTOBitcodeEmbedding::EmbedOptimized)
387 llvm::EmbedBitcodeInModule(Mod, llvm::MemoryBufferRef(),
388 /*EmbedBitcode*/ true,
389 /*EmbedCmdline*/ false,
390 /*CmdArgs*/ std::vector<uint8_t>());
391
392 std::unique_ptr<ToolOutputFile> DwoOut;
393 SmallString<1024> DwoFile(Conf.SplitDwarfOutput);
394 if (!Conf.DwoDir.empty()) {
395 std::error_code EC;
396 if (auto EC = llvm::sys::fs::create_directories(Conf.DwoDir))
397 report_fatal_error("Failed to create directory " + Conf.DwoDir + ": " +
398 EC.message());
399
400 DwoFile = Conf.DwoDir;
401 sys::path::append(DwoFile, std::to_string(Task) + ".dwo");
402 TM->Options.MCOptions.SplitDwarfFile = std::string(DwoFile);
403 } else
404 TM->Options.MCOptions.SplitDwarfFile = Conf.SplitDwarfFile;
405
406 if (!DwoFile.empty()) {
407 std::error_code EC;
408 DwoOut = std::make_unique<ToolOutputFile>(DwoFile, EC, sys::fs::OF_None);
409 if (EC)
410 report_fatal_error("Failed to open " + DwoFile + ": " + EC.message());
411 }
412
413 auto Stream = AddStream(Task);
414 legacy::PassManager CodeGenPasses;
415 CodeGenPasses.add(
416 createImmutableModuleSummaryIndexWrapperPass(&CombinedIndex));
417 if (Conf.PreCodeGenPassesHook)
418 Conf.PreCodeGenPassesHook(CodeGenPasses);
419 if (TM->addPassesToEmitFile(CodeGenPasses, *Stream->OS,
420 DwoOut ? &DwoOut->os() : nullptr,
421 Conf.CGFileType))
422 report_fatal_error("Failed to setup codegen");
423 CodeGenPasses.run(Mod);
424
425 if (DwoOut)
426 DwoOut->keep();
427}
428
429static void splitCodeGen(const Config &C, TargetMachine *TM,
430 AddStreamFn AddStream,
431 unsigned ParallelCodeGenParallelismLevel, Module &Mod,
432 const ModuleSummaryIndex &CombinedIndex) {
433 ThreadPool CodegenThreadPool(
434 heavyweight_hardware_concurrency(ParallelCodeGenParallelismLevel));
435 unsigned ThreadCount = 0;
436 const Target *T = &TM->getTarget();
437
438 SplitModule(
439 Mod, ParallelCodeGenParallelismLevel,
440 [&](std::unique_ptr<Module> MPart) {
441 // We want to clone the module in a new context to multi-thread the
442 // codegen. We do it by serializing partition modules to bitcode
443 // (while still on the main thread, in order to avoid data races) and
444 // spinning up new threads which deserialize the partitions into
445 // separate contexts.
446 // FIXME: Provide a more direct way to do this in LLVM.
447 SmallString<0> BC;
448 raw_svector_ostream BCOS(BC);
449 WriteBitcodeToFile(*MPart, BCOS);
450
451 // Enqueue the task
452 CodegenThreadPool.async(
453 [&](const SmallString<0> &BC, unsigned ThreadId) {
454 LTOLLVMContext Ctx(C);
455 Expected<std::unique_ptr<Module>> MOrErr = parseBitcodeFile(
456 MemoryBufferRef(StringRef(BC.data(), BC.size()), "ld-temp.o"),
457 Ctx);
458 if (!MOrErr)
459 report_fatal_error("Failed to read bitcode");
460 std::unique_ptr<Module> MPartInCtx = std::move(MOrErr.get());
461
462 std::unique_ptr<TargetMachine> TM =
463 createTargetMachine(C, T, *MPartInCtx);
464
465 codegen(C, TM.get(), AddStream, ThreadId, *MPartInCtx,
466 CombinedIndex);
467 },
468 // Pass BC using std::move to ensure that it get moved rather than
469 // copied into the thread's context.
470 std::move(BC), ThreadCount++);
471 },
472 false);
473
474 // Because the inner lambda (which runs in a worker thread) captures our local
475 // variables, we need to wait for the worker threads to terminate before we
476 // can leave the function scope.
477 CodegenThreadPool.wait();
478}
479
480static Expected<const Target *> initAndLookupTarget(const Config &C,
481 Module &Mod) {
482 if (!C.OverrideTriple.empty())
483 Mod.setTargetTriple(C.OverrideTriple);
484 else if (Mod.getTargetTriple().empty())
485 Mod.setTargetTriple(C.DefaultTriple);
486
487 std::string Msg;
488 const Target *T = TargetRegistry::lookupTarget(Mod.getTargetTriple(), Msg);
489 if (!T)
490 return make_error<StringError>(Msg, inconvertibleErrorCode());
491 return T;
492}
493
494Error lto::finalizeOptimizationRemarks(
495 std::unique_ptr<ToolOutputFile> DiagOutputFile) {
496 // Make sure we flush the diagnostic remarks file in case the linker doesn't
497 // call the global destructors before exiting.
498 if (!DiagOutputFile)
499 return Error::success();
500 DiagOutputFile->keep();
501 DiagOutputFile->os().flush();
502 return Error::success();
503}
504
505Error lto::backend(const Config &C, AddStreamFn AddStream,
506 unsigned ParallelCodeGenParallelismLevel, Module &Mod,
507 ModuleSummaryIndex &CombinedIndex) {
508 Expected<const Target *> TOrErr = initAndLookupTarget(C, Mod);
509 if (!TOrErr)
1
Calling 'Expected::operator bool'
3
Returning from 'Expected::operator bool'
4
Taking false branch
510 return TOrErr.takeError();
511
512 std::unique_ptr<TargetMachine> TM = createTargetMachine(C, *TOrErr, Mod);
5
Value assigned to 'TM._M_t._M_t._M_head_impl'
513
514 if (!C.CodeGenOnly) {
6
Assuming field 'CodeGenOnly' is false
7
Taking true branch
515 if (!opt(C, TM.get(), 0, Mod, /*IsThinLTO=*/false,
8
Passing value via 2nd parameter 'TM'
9
Calling 'opt'
516 /*ExportSummary=*/&CombinedIndex, /*ImportSummary=*/nullptr,
517 /*CmdArgs*/ std::vector<uint8_t>()))
518 return Error::success();
519 }
520
521 if (ParallelCodeGenParallelismLevel == 1) {
522 codegen(C, TM.get(), AddStream, 0, Mod, CombinedIndex);
523 } else {
524 splitCodeGen(C, TM.get(), AddStream, ParallelCodeGenParallelismLevel, Mod,
525 CombinedIndex);
526 }
527 return Error::success();
528}
529
530static void dropDeadSymbols(Module &Mod, const GVSummaryMapTy &DefinedGlobals,
531 const ModuleSummaryIndex &Index) {
532 std::vector<GlobalValue*> DeadGVs;
533 for (auto &GV : Mod.global_values())
534 if (GlobalValueSummary *GVS = DefinedGlobals.lookup(GV.getGUID()))
535 if (!Index.isGlobalValueLive(GVS)) {
536 DeadGVs.push_back(&GV);
537 convertToDeclaration(GV);
538 }
539
540 // Now that all dead bodies have been dropped, delete the actual objects
541 // themselves when possible.
542 for (GlobalValue *GV : DeadGVs) {
543 GV->removeDeadConstantUsers();
544 // Might reference something defined in native object (i.e. dropped a
545 // non-prevailing IR def, but we need to keep the declaration).
546 if (GV->use_empty())
547 GV->eraseFromParent();
548 }
549}
550
551Error lto::thinBackend(const Config &Conf, unsigned Task, AddStreamFn AddStream,
552 Module &Mod, const ModuleSummaryIndex &CombinedIndex,
553 const FunctionImporter::ImportMapTy &ImportList,
554 const GVSummaryMapTy &DefinedGlobals,
555 MapVector<StringRef, BitcodeModule> *ModuleMap,
556 const std::vector<uint8_t> &CmdArgs) {
557 Expected<const Target *> TOrErr = initAndLookupTarget(Conf, Mod);
558 if (!TOrErr)
559 return TOrErr.takeError();
560
561 std::unique_ptr<TargetMachine> TM = createTargetMachine(Conf, *TOrErr, Mod);
562
563 // Setup optimization remarks.
564 auto DiagFileOrErr = lto::setupLLVMOptimizationRemarks(
565 Mod.getContext(), Conf.RemarksFilename, Conf.RemarksPasses,
566 Conf.RemarksFormat, Conf.RemarksWithHotness, Conf.RemarksHotnessThreshold,
567 Task);
568 if (!DiagFileOrErr)
569 return DiagFileOrErr.takeError();
570 auto DiagnosticOutputFile = std::move(*DiagFileOrErr);
571
572 // Set the partial sample profile ratio in the profile summary module flag of
573 // the module, if applicable.
574 Mod.setPartialSampleProfileRatio(CombinedIndex);
575
576 if (Conf.CodeGenOnly) {
577 codegen(Conf, TM.get(), AddStream, Task, Mod, CombinedIndex);
578 return finalizeOptimizationRemarks(std::move(DiagnosticOutputFile));
579 }
580
581 if (Conf.PreOptModuleHook && !Conf.PreOptModuleHook(Task, Mod))
582 return finalizeOptimizationRemarks(std::move(DiagnosticOutputFile));
583
584 auto OptimizeAndCodegen =
585 [&](Module &Mod, TargetMachine *TM,
586 std::unique_ptr<ToolOutputFile> DiagnosticOutputFile) {
587 if (!opt(Conf, TM, Task, Mod, /*IsThinLTO=*/true,
588 /*ExportSummary=*/nullptr, /*ImportSummary=*/&CombinedIndex,
589 CmdArgs))
590 return finalizeOptimizationRemarks(std::move(DiagnosticOutputFile));
591
592 codegen(Conf, TM, AddStream, Task, Mod, CombinedIndex);
593 return finalizeOptimizationRemarks(std::move(DiagnosticOutputFile));
594 };
595
596 if (ThinLTOAssumeMerged)
597 return OptimizeAndCodegen(Mod, TM.get(), std::move(DiagnosticOutputFile));
598
599 // When linking an ELF shared object, dso_local should be dropped. We
600 // conservatively do this for -fpic.
601 bool ClearDSOLocalOnDeclarations =
602 TM->getTargetTriple().isOSBinFormatELF() &&
603 TM->getRelocationModel() != Reloc::Static &&
604 Mod.getPIELevel() == PIELevel::Default;
605 renameModuleForThinLTO(Mod, CombinedIndex, ClearDSOLocalOnDeclarations);
606
607 dropDeadSymbols(Mod, DefinedGlobals, CombinedIndex);
608
609 thinLTOResolvePrevailingInModule(Mod, DefinedGlobals);
610
611 if (Conf.PostPromoteModuleHook && !Conf.PostPromoteModuleHook(Task, Mod))
612 return finalizeOptimizationRemarks(std::move(DiagnosticOutputFile));
613
614 if (!DefinedGlobals.empty())
615 thinLTOInternalizeModule(Mod, DefinedGlobals);
616
617 if (Conf.PostInternalizeModuleHook &&
618 !Conf.PostInternalizeModuleHook(Task, Mod))
619 return finalizeOptimizationRemarks(std::move(DiagnosticOutputFile));
620
621 auto ModuleLoader = [&](StringRef Identifier) {
622 assert(Mod.getContext().isODRUniquingDebugTypes() &&(static_cast<void> (0))
623 "ODR Type uniquing should be enabled on the context")(static_cast<void> (0));
624 if (ModuleMap) {
625 auto I = ModuleMap->find(Identifier);
626 assert(I != ModuleMap->end())(static_cast<void> (0));
627 return I->second.getLazyModule(Mod.getContext(),
628 /*ShouldLazyLoadMetadata=*/true,
629 /*IsImporting*/ true);
630 }
631
632 ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MBOrErr =
633 llvm::MemoryBuffer::getFile(Identifier);
634 if (!MBOrErr)
635 return Expected<std::unique_ptr<llvm::Module>>(make_error<StringError>(
636 Twine("Error loading imported file ") + Identifier + " : ",
637 MBOrErr.getError()));
638
639 Expected<BitcodeModule> BMOrErr = findThinLTOModule(**MBOrErr);
640 if (!BMOrErr)
641 return Expected<std::unique_ptr<llvm::Module>>(make_error<StringError>(
642 Twine("Error loading imported file ") + Identifier + " : " +
643 toString(BMOrErr.takeError()),
644 inconvertibleErrorCode()));
645
646 Expected<std::unique_ptr<Module>> MOrErr =
647 BMOrErr->getLazyModule(Mod.getContext(),
648 /*ShouldLazyLoadMetadata=*/true,
649 /*IsImporting*/ true);
650 if (MOrErr)
651 (*MOrErr)->setOwnedMemoryBuffer(std::move(*MBOrErr));
652 return MOrErr;
653 };
654
655 FunctionImporter Importer(CombinedIndex, ModuleLoader,
656 ClearDSOLocalOnDeclarations);
657 if (Error Err = Importer.importFunctions(Mod, ImportList).takeError())
658 return Err;
659
660 if (Conf.PostImportModuleHook && !Conf.PostImportModuleHook(Task, Mod))
661 return finalizeOptimizationRemarks(std::move(DiagnosticOutputFile));
662
663 return OptimizeAndCodegen(Mod, TM.get(), std::move(DiagnosticOutputFile));
664}
665
666BitcodeModule *lto::findThinLTOModule(MutableArrayRef<BitcodeModule> BMs) {
667 if (ThinLTOAssumeMerged && BMs.size() == 1)
668 return BMs.begin();
669
670 for (BitcodeModule &BM : BMs) {
671 Expected<BitcodeLTOInfo> LTOInfo = BM.getLTOInfo();
672 if (LTOInfo && LTOInfo->IsThinLTO)
673 return &BM;
674 }
675 return nullptr;
676}
677
678Expected<BitcodeModule> lto::findThinLTOModule(MemoryBufferRef MBRef) {
679 Expected<std::vector<BitcodeModule>> BMsOrErr = getBitcodeModuleList(MBRef);
680 if (!BMsOrErr)
681 return BMsOrErr.takeError();
682
683 // The bitcode file may contain multiple modules, we want the one that is
684 // marked as being the ThinLTO module.
685 if (const BitcodeModule *Bm = lto::findThinLTOModule(*BMsOrErr))
686 return *Bm;
687
688 return make_error<StringError>("Could not find module summary",
689 inconvertibleErrorCode());
690}
691
692bool lto::initImportList(const Module &M,
693 const ModuleSummaryIndex &CombinedIndex,
694 FunctionImporter::ImportMapTy &ImportList) {
695 if (ThinLTOAssumeMerged)
696 return true;
697 // We can simply import the values mentioned in the combined index, since
698 // we should only invoke this using the individual indexes written out
699 // via a WriteIndexesThinBackend.
700 for (const auto &GlobalList : CombinedIndex) {
701 // Ignore entries for undefined references.
702 if (GlobalList.second.SummaryList.empty())
703 continue;
704
705 auto GUID = GlobalList.first;
706 for (const auto &Summary : GlobalList.second.SummaryList) {
707 // Skip the summaries for the importing module. These are included to
708 // e.g. record required linkage changes.
709 if (Summary->modulePath() == M.getModuleIdentifier())
710 continue;
711 // Add an entry to provoke importing by thinBackend.
712 ImportList[Summary->modulePath()].insert(GUID);
713 }
714 }
715 return true;
716}

/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/include/llvm/Support/Error.h

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
42namespace llvm {
43
44class ErrorSuccess;
45
46/// Base class for error info classes. Do not extend this directly: Extend
47/// the ErrorInfo template subclass instead.
48class ErrorInfoBase {
49public:
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
86private:
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.
157class 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
174protected:
175 /// Create a success value. Prefer using 'Error::success()' for readability
176 Error() {
177 setPtr(nullptr);
178 setChecked(false);
179 }
180
181public:
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
253private:
254#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
255 // assertIsChecked() happens very frequently, but under normal circumstances
256 // is supposed to be a no-op. So we want it to be inlined, but having a bunch
257 // of debug prints can cause the function to be too large for inlining. So
258 // it's important that we define this function out of line so that it can't be
259 // inlined.
260 [[noreturn]] void fatalUncheckedError() const;
261#endif
262
263 void assertIsChecked() {
264#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
265 if (LLVM_UNLIKELY(!getChecked() || getPtr())__builtin_expect((bool)(!getChecked() || getPtr()), false))
266 fatalUncheckedError();
267#endif
268 }
269
270 ErrorInfoBase *getPtr() const {
271#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
272 return reinterpret_cast<ErrorInfoBase*>(
273 reinterpret_cast<uintptr_t>(Payload) &
274 ~static_cast<uintptr_t>(0x1));
275#else
276 return Payload;
277#endif
278 }
279
280 void setPtr(ErrorInfoBase *EI) {
281#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
282 Payload = reinterpret_cast<ErrorInfoBase*>(
283 (reinterpret_cast<uintptr_t>(EI) &
284 ~static_cast<uintptr_t>(0x1)) |
285 (reinterpret_cast<uintptr_t>(Payload) & 0x1));
286#else
287 Payload = EI;
288#endif
289 }
290
291 bool getChecked() const {
292#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
293 return (reinterpret_cast<uintptr_t>(Payload) & 0x1) == 0;
294#else
295 return true;
296#endif
297 }
298
299 void setChecked(bool V) {
300#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
301 Payload = reinterpret_cast<ErrorInfoBase*>(
302 (reinterpret_cast<uintptr_t>(Payload) &
303 ~static_cast<uintptr_t>(0x1)) |
304 (V ? 0 : 1));
305#endif
306 }
307
308 std::unique_ptr<ErrorInfoBase> takePayload() {
309 std::unique_ptr<ErrorInfoBase> Tmp(getPtr());
310 setPtr(nullptr);
311 setChecked(true);
312 return Tmp;
313 }
314
315 friend raw_ostream &operator<<(raw_ostream &OS, const Error &E) {
316 if (auto P = E.getPtr())
317 P->log(OS);
318 else
319 OS << "success";
320 return OS;
321 }
322
323 ErrorInfoBase *Payload = nullptr;
324};
325
326/// Subclass of Error for the sole purpose of identifying the success path in
327/// the type system. This allows to catch invalid conversion to Expected<T> at
328/// compile time.
329class ErrorSuccess final : public Error {};
330
331inline ErrorSuccess Error::success() { return ErrorSuccess(); }
332
333/// Make a Error instance representing failure using the given error info
334/// type.
335template <typename ErrT, typename... ArgTs> Error make_error(ArgTs &&... Args) {
336 return Error(std::make_unique<ErrT>(std::forward<ArgTs>(Args)...));
337}
338
339/// Base class for user error types. Users should declare their error types
340/// like:
341///
342/// class MyError : public ErrorInfo<MyError> {
343/// ....
344/// };
345///
346/// This class provides an implementation of the ErrorInfoBase::kind
347/// method, which is used by the Error RTTI system.
348template <typename ThisErrT, typename ParentErrT = ErrorInfoBase>
349class ErrorInfo : public ParentErrT {
350public:
351 using ParentErrT::ParentErrT; // inherit constructors
352
353 static const void *classID() { return &ThisErrT::ID; }
354
355 const void *dynamicClassID() const override { return &ThisErrT::ID; }
356
357 bool isA(const void *const ClassID) const override {
358 return ClassID == classID() || ParentErrT::isA(ClassID);
359 }
360};
361
362/// Special ErrorInfo subclass representing a list of ErrorInfos.
363/// Instances of this class are constructed by joinError.
364class ErrorList final : public ErrorInfo<ErrorList> {
365 // handleErrors needs to be able to iterate the payload list of an
366 // ErrorList.
367 template <typename... HandlerTs>
368 friend Error handleErrors(Error E, HandlerTs &&... Handlers);
369
370 // joinErrors is implemented in terms of join.
371 friend Error joinErrors(Error, Error);
372
373public:
374 void log(raw_ostream &OS) const override {
375 OS << "Multiple errors:\n";
376 for (auto &ErrPayload : Payloads) {
377 ErrPayload->log(OS);
378 OS << "\n";
379 }
380 }
381
382 std::error_code convertToErrorCode() const override;
383
384 // Used by ErrorInfo::classID.
385 static char ID;
386
387private:
388 ErrorList(std::unique_ptr<ErrorInfoBase> Payload1,
389 std::unique_ptr<ErrorInfoBase> Payload2) {
390 assert(!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() &&(static_cast<void> (0))
391 "ErrorList constructor payloads should be singleton errors")(static_cast<void> (0));
392 Payloads.push_back(std::move(Payload1));
393 Payloads.push_back(std::move(Payload2));
394 }
395
396 static Error join(Error E1, Error E2) {
397 if (!E1)
398 return E2;
399 if (!E2)
400 return E1;
401 if (E1.isA<ErrorList>()) {
402 auto &E1List = static_cast<ErrorList &>(*E1.getPtr());
403 if (E2.isA<ErrorList>()) {
404 auto E2Payload = E2.takePayload();
405 auto &E2List = static_cast<ErrorList &>(*E2Payload);
406 for (auto &Payload : E2List.Payloads)
407 E1List.Payloads.push_back(std::move(Payload));
408 } else
409 E1List.Payloads.push_back(E2.takePayload());
410
411 return E1;
412 }
413 if (E2.isA<ErrorList>()) {
414 auto &E2List = static_cast<ErrorList &>(*E2.getPtr());
415 E2List.Payloads.insert(E2List.Payloads.begin(), E1.takePayload());
416 return E2;
417 }
418 return Error(std::unique_ptr<ErrorList>(
419 new ErrorList(E1.takePayload(), E2.takePayload())));
420 }
421
422 std::vector<std::unique_ptr<ErrorInfoBase>> Payloads;
423};
424
425/// Concatenate errors. The resulting Error is unchecked, and contains the
426/// ErrorInfo(s), if any, contained in E1, followed by the
427/// ErrorInfo(s), if any, contained in E2.
428inline Error joinErrors(Error E1, Error E2) {
429 return ErrorList::join(std::move(E1), std::move(E2));
430}
431
432/// Tagged union holding either a T or a Error.
433///
434/// This class parallels ErrorOr, but replaces error_code with Error. Since
435/// Error cannot be copied, this class replaces getError() with
436/// takeError(). It also adds an bool errorIsA<ErrT>() method for testing the
437/// error class type.
438///
439/// Example usage of 'Expected<T>' as a function return type:
440///
441/// @code{.cpp}
442/// Expected<int> myDivide(int A, int B) {
443/// if (B == 0) {
444/// // return an Error
445/// return createStringError(inconvertibleErrorCode(),
446/// "B must not be zero!");
447/// }
448/// // return an integer
449/// return A / B;
450/// }
451/// @endcode
452///
453/// Checking the results of to a function returning 'Expected<T>':
454/// @code{.cpp}
455/// if (auto E = Result.takeError()) {
456/// // We must consume the error. Typically one of:
457/// // - return the error to our caller
458/// // - toString(), when logging
459/// // - consumeError(), to silently swallow the error
460/// // - handleErrors(), to distinguish error types
461/// errs() << "Problem with division " << toString(std::move(E)) << "\n";
462/// return;
463/// }
464/// // use the result
465/// outs() << "The answer is " << *Result << "\n";
466/// @endcode
467///
468/// For unit-testing a function returning an 'Expceted<T>', see the
469/// 'EXPECT_THAT_EXPECTED' macros in llvm/Testing/Support/Error.h
470
471template <class T> class LLVM_NODISCARD[[clang::warn_unused_result]] Expected {
472 template <class T1> friend class ExpectedAsOutParameter;
473 template <class OtherT> friend class Expected;
474
475 static constexpr bool isRef = std::is_reference<T>::value;
476
477 using wrap = std::reference_wrapper<std::remove_reference_t<T>>;
478
479 using error_type = std::unique_ptr<ErrorInfoBase>;
480
481public:
482 using storage_type = std::conditional_t<isRef, wrap, T>;
483 using value_type = T;
484
485private:
486 using reference = std::remove_reference_t<T> &;
487 using const_reference = const std::remove_reference_t<T> &;
488 using pointer = std::remove_reference_t<T> *;
489 using const_pointer = const std::remove_reference_t<T> *;
490
491public:
492 /// Create an Expected<T> error value from the given Error.
493 Expected(Error Err)
494 : HasError(true)
495#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
496 // Expected is unchecked upon construction in Debug builds.
497 , Unchecked(true)
498#endif
499 {
500 assert(Err && "Cannot create Expected<T> from Error success value.")(static_cast<void> (0));
501 new (getErrorStorage()) error_type(Err.takePayload());
502 }
503
504 /// Forbid to convert from Error::success() implicitly, this avoids having
505 /// Expected<T> foo() { return Error::success(); } which compiles otherwise
506 /// but triggers the assertion above.
507 Expected(ErrorSuccess) = delete;
508
509 /// Create an Expected<T> success value from the given OtherT value, which
510 /// must be convertible to T.
511 template <typename OtherT>
512 Expected(OtherT &&Val,
513 std::enable_if_t<std::is_convertible<OtherT, T>::value> * = nullptr)
514 : HasError(false)
515#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
516 // Expected is unchecked upon construction in Debug builds.
517 ,
518 Unchecked(true)
519#endif
520 {
521 new (getStorage()) storage_type(std::forward<OtherT>(Val));
522 }
523
524 /// Move construct an Expected<T> value.
525 Expected(Expected &&Other) { moveConstruct(std::move(Other)); }
526
527 /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT
528 /// must be convertible to T.
529 template <class OtherT>
530 Expected(
531 Expected<OtherT> &&Other,
532 std::enable_if_t<std::is_convertible<OtherT, T>::value> * = nullptr) {
533 moveConstruct(std::move(Other));
534 }
535
536 /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT
537 /// isn't convertible to T.
538 template <class OtherT>
539 explicit Expected(
540 Expected<OtherT> &&Other,
541 std::enable_if_t<!std::is_convertible<OtherT, T>::value> * = nullptr) {
542 moveConstruct(std::move(Other));
543 }
544
545 /// Move-assign from another Expected<T>.
546 Expected &operator=(Expected &&Other) {
547 moveAssign(std::move(Other));
548 return *this;
549 }
550
551 /// Destroy an Expected<T>.
552 ~Expected() {
553 assertIsChecked();
554 if (!HasError)
555 getStorage()->~storage_type();
556 else
557 getErrorStorage()->~error_type();
558 }
559
560 /// Return false if there is an error.
561 explicit operator bool() {
562#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
563 Unchecked = HasError;
564#endif
565 return !HasError;
2
Returning the value 1, which participates in a condition later
566 }
567
568 /// Returns a reference to the stored T value.
569 reference get() {
570 assertIsChecked();
571 return *getStorage();
572 }
573
574 /// Returns a const reference to the stored T value.
575 const_reference get() const {
576 assertIsChecked();
577 return const_cast<Expected<T> *>(this)->get();
578 }
579
580 /// Check that this Expected<T> is an error of type ErrT.
581 template <typename ErrT> bool errorIsA() const {
582 return HasError && (*getErrorStorage())->template isA<ErrT>();
583 }
584
585 /// Take ownership of the stored error.
586 /// After calling this the Expected<T> is in an indeterminate state that can
587 /// only be safely destructed. No further calls (beside the destructor) should
588 /// be made on the Expected<T> value.
589 Error takeError() {
590#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
591 Unchecked = false;
592#endif
593 return HasError ? Error(std::move(*getErrorStorage())) : Error::success();
594 }
595
596 /// Returns a pointer to the stored T value.
597 pointer operator->() {
598 assertIsChecked();
599 return toPointer(getStorage());
600 }
601
602 /// Returns a const pointer to the stored T value.
603 const_pointer operator->() const {
604 assertIsChecked();
605 return toPointer(getStorage());
606 }
607
608 /// Returns a reference to the stored T value.
609 reference operator*() {
610 assertIsChecked();
611 return *getStorage();
612 }
613
614 /// Returns a const reference to the stored T value.
615 const_reference operator*() const {
616 assertIsChecked();
617 return *getStorage();
618 }
619
620private:
621 template <class T1>
622 static bool compareThisIfSameType(const T1 &a, const T1 &b) {
623 return &a == &b;
624 }
625
626 template <class T1, class T2>
627 static bool compareThisIfSameType(const T1 &, const T2 &) {
628 return false;
629 }
630
631 template <class OtherT> void moveConstruct(Expected<OtherT> &&Other) {
632 HasError = Other.HasError;
633#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
634 Unchecked = true;
635 Other.Unchecked = false;
636#endif
637
638 if (!HasError)
639 new (getStorage()) storage_type(std::move(*Other.getStorage()));
640 else
641 new (getErrorStorage()) error_type(std::move(*Other.getErrorStorage()));
642 }
643
644 template <class OtherT> void moveAssign(Expected<OtherT> &&Other) {
645 assertIsChecked();
646
647 if (compareThisIfSameType(*this, Other))
648 return;
649
650 this->~Expected();
651 new (this) Expected(std::move(Other));
652 }
653
654 pointer toPointer(pointer Val) { return Val; }
655
656 const_pointer toPointer(const_pointer Val) const { return Val; }
657
658 pointer toPointer(wrap *Val) { return &Val->get(); }
659
660 const_pointer toPointer(const wrap *Val) const { return &Val->get(); }
661
662 storage_type *getStorage() {
663 assert(!HasError && "Cannot get value when an error exists!")(static_cast<void> (0));
664 return reinterpret_cast<storage_type *>(&TStorage);
665 }
666
667 const storage_type *getStorage() const {
668 assert(!HasError && "Cannot get value when an error exists!")(static_cast<void> (0));
669 return reinterpret_cast<const storage_type *>(&TStorage);
670 }
671
672 error_type *getErrorStorage() {
673 assert(HasError && "Cannot get error when a value exists!")(static_cast<void> (0));
674 return reinterpret_cast<error_type *>(&ErrorStorage);
675 }
676
677 const error_type *getErrorStorage() const {
678 assert(HasError && "Cannot get error when a value exists!")(static_cast<void> (0));
679 return reinterpret_cast<const error_type *>(&ErrorStorage);
680 }
681
682 // Used by ExpectedAsOutParameter to reset the checked flag.
683 void setUnchecked() {
684#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
685 Unchecked = true;
686#endif
687 }
688
689#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
690 [[noreturn]] LLVM_ATTRIBUTE_NOINLINE__attribute__((noinline)) void fatalUncheckedExpected() const {
691 dbgs() << "Expected<T> must be checked before access or destruction.\n";
692 if (HasError) {
693 dbgs() << "Unchecked Expected<T> contained error:\n";
694 (*getErrorStorage())->log(dbgs());
695 } else
696 dbgs() << "Expected<T> value was in success state. (Note: Expected<T> "
697 "values in success mode must still be checked prior to being "
698 "destroyed).\n";
699 abort();
700 }
701#endif
702
703 void assertIsChecked() const {
704#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
705 if (LLVM_UNLIKELY(Unchecked)__builtin_expect((bool)(Unchecked), false))
706 fatalUncheckedExpected();
707#endif
708 }
709
710 union {
711 AlignedCharArrayUnion<storage_type> TStorage;
712 AlignedCharArrayUnion<error_type> ErrorStorage;
713 };
714 bool HasError : 1;
715#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
716 bool Unchecked : 1;
717#endif
718};
719
720/// Report a serious error, calling any installed error handler. See
721/// ErrorHandling.h.
722[[noreturn]] void report_fatal_error(Error Err, bool gen_crash_diag = true);
723
724/// Report a fatal error if Err is a failure value.
725///
726/// This function can be used to wrap calls to fallible functions ONLY when it
727/// is known that the Error will always be a success value. E.g.
728///
729/// @code{.cpp}
730/// // foo only attempts the fallible operation if DoFallibleOperation is
731/// // true. If DoFallibleOperation is false then foo always returns
732/// // Error::success().
733/// Error foo(bool DoFallibleOperation);
734///
735/// cantFail(foo(false));
736/// @endcode
737inline void cantFail(Error Err, const char *Msg = nullptr) {
738 if (Err) {
739 if (!Msg)
740 Msg = "Failure value returned from cantFail wrapped call";
741#ifndef NDEBUG1
742 std::string Str;
743 raw_string_ostream OS(Str);
744 OS << Msg << "\n" << Err;
745 Msg = OS.str().c_str();
746#endif
747 llvm_unreachable(Msg)__builtin_unreachable();
748 }
749}
750
751/// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and
752/// returns the contained value.
753///
754/// This function can be used to wrap calls to fallible functions ONLY when it
755/// is known that the Error will always be a success value. E.g.
756///
757/// @code{.cpp}
758/// // foo only attempts the fallible operation if DoFallibleOperation is
759/// // true. If DoFallibleOperation is false then foo always returns an int.
760/// Expected<int> foo(bool DoFallibleOperation);
761///
762/// int X = cantFail(foo(false));
763/// @endcode
764template <typename T>
765T cantFail(Expected<T> ValOrErr, const char *Msg = nullptr) {
766 if (ValOrErr)
767 return std::move(*ValOrErr);
768 else {
769 if (!Msg)
770 Msg = "Failure value returned from cantFail wrapped call";
771#ifndef NDEBUG1
772 std::string Str;
773 raw_string_ostream OS(Str);
774 auto E = ValOrErr.takeError();
775 OS << Msg << "\n" << E;
776 Msg = OS.str().c_str();
777#endif
778 llvm_unreachable(Msg)__builtin_unreachable();
779 }
780}
781
782/// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and
783/// returns the contained reference.
784///
785/// This function can be used to wrap calls to fallible functions ONLY when it
786/// is known that the Error will always be a success value. E.g.
787///
788/// @code{.cpp}
789/// // foo only attempts the fallible operation if DoFallibleOperation is
790/// // true. If DoFallibleOperation is false then foo always returns a Bar&.
791/// Expected<Bar&> foo(bool DoFallibleOperation);
792///
793/// Bar &X = cantFail(foo(false));
794/// @endcode
795template <typename T>
796T& cantFail(Expected<T&> ValOrErr, const char *Msg = nullptr) {
797 if (ValOrErr)
798 return *ValOrErr;
799 else {
800 if (!Msg)
801 Msg = "Failure value returned from cantFail wrapped call";
802#ifndef NDEBUG1
803 std::string Str;
804 raw_string_ostream OS(Str);
805 auto E = ValOrErr.takeError();
806 OS << Msg << "\n" << E;
807 Msg = OS.str().c_str();
808#endif
809 llvm_unreachable(Msg)__builtin_unreachable();
810 }
811}
812
813/// Helper for testing applicability of, and applying, handlers for
814/// ErrorInfo types.
815template <typename HandlerT>
816class ErrorHandlerTraits
817 : public ErrorHandlerTraits<decltype(
818 &std::remove_reference<HandlerT>::type::operator())> {};
819
820// Specialization functions of the form 'Error (const ErrT&)'.
821template <typename ErrT> class ErrorHandlerTraits<Error (&)(ErrT &)> {
822public:
823 static bool appliesTo(const ErrorInfoBase &E) {
824 return E.template isA<ErrT>();
825 }
826
827 template <typename HandlerT>
828 static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
829 assert(appliesTo(*E) && "Applying incorrect handler")(static_cast<void> (0));
830 return H(static_cast<ErrT &>(*E));
831 }
832};
833
834// Specialization functions of the form 'void (const ErrT&)'.
835template <typename ErrT> class ErrorHandlerTraits<void (&)(ErrT &)> {
836public:
837 static bool appliesTo(const ErrorInfoBase &E) {
838 return E.template isA<ErrT>();
839 }
840
841 template <typename HandlerT>
842 static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
843 assert(appliesTo(*E) && "Applying incorrect handler")(static_cast<void> (0));
844 H(static_cast<ErrT &>(*E));
845 return Error::success();
846 }
847};
848
849/// Specialization for functions of the form 'Error (std::unique_ptr<ErrT>)'.
850template <typename ErrT>
851class ErrorHandlerTraits<Error (&)(std::unique_ptr<ErrT>)> {
852public:
853 static bool appliesTo(const ErrorInfoBase &E) {
854 return E.template isA<ErrT>();
855 }
856
857 template <typename HandlerT>
858 static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
859 assert(appliesTo(*E) && "Applying incorrect handler")(static_cast<void> (0));
860 std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release()));
861 return H(std::move(SubE));
862 }
863};
864
865/// Specialization for functions of the form 'void (std::unique_ptr<ErrT>)'.
866template <typename ErrT>
867class ErrorHandlerTraits<void (&)(std::unique_ptr<ErrT>)> {
868public:
869 static bool appliesTo(const ErrorInfoBase &E) {
870 return E.template isA<ErrT>();
871 }
872
873 template <typename HandlerT>
874 static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
875 assert(appliesTo(*E) && "Applying incorrect handler")(static_cast<void> (0));
876 std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release()));
877 H(std::move(SubE));
878 return Error::success();
879 }
880};
881
882// Specialization for member functions of the form 'RetT (const ErrT&)'.
883template <typename C, typename RetT, typename ErrT>
884class ErrorHandlerTraits<RetT (C::*)(ErrT &)>
885 : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
886
887// Specialization for member functions of the form 'RetT (const ErrT&) const'.
888template <typename C, typename RetT, typename ErrT>
889class ErrorHandlerTraits<RetT (C::*)(ErrT &) const>
890 : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
891
892// Specialization for member functions of the form 'RetT (const ErrT&)'.
893template <typename C, typename RetT, typename ErrT>
894class ErrorHandlerTraits<RetT (C::*)(const ErrT &)>
895 : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
896
897// Specialization for member functions of the form 'RetT (const ErrT&) const'.
898template <typename C, typename RetT, typename ErrT>
899class ErrorHandlerTraits<RetT (C::*)(const ErrT &) const>
900 : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
901
902/// Specialization for member functions of the form
903/// 'RetT (std::unique_ptr<ErrT>)'.
904template <typename C, typename RetT, typename ErrT>
905class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>)>
906 : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {};
907
908/// Specialization for member functions of the form
909/// 'RetT (std::unique_ptr<ErrT>) const'.
910template <typename C, typename RetT, typename ErrT>
911class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>) const>
912 : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {};
913
914inline Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload) {
915 return Error(std::move(Payload));
916}
917
918template <typename HandlerT, typename... HandlerTs>
919Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload,
920 HandlerT &&Handler, HandlerTs &&... Handlers) {
921 if (ErrorHandlerTraits<HandlerT>::appliesTo(*Payload))
922 return ErrorHandlerTraits<HandlerT>::apply(std::forward<HandlerT>(Handler),
923 std::move(Payload));
924 return handleErrorImpl(std::move(Payload),
925 std::forward<HandlerTs>(Handlers)...);
926}
927
928/// Pass the ErrorInfo(s) contained in E to their respective handlers. Any
929/// unhandled errors (or Errors returned by handlers) are re-concatenated and
930/// returned.
931/// Because this function returns an error, its result must also be checked
932/// or returned. If you intend to handle all errors use handleAllErrors
933/// (which returns void, and will abort() on unhandled errors) instead.
934template <typename... HandlerTs>
935Error handleErrors(Error E, HandlerTs &&... Hs) {
936 if (!E)
937 return Error::success();
938
939 std::unique_ptr<ErrorInfoBase> Payload = E.takePayload();
940
941 if (Payload->isA<ErrorList>()) {
942 ErrorList &List = static_cast<ErrorList &>(*Payload);
943 Error R;
944 for (auto &P : List.Payloads)
945 R = ErrorList::join(
946 std::move(R),
947 handleErrorImpl(std::move(P), std::forward<HandlerTs>(Hs)...));
948 return R;
949 }
950
951 return handleErrorImpl(std::move(Payload), std::forward<HandlerTs>(Hs)...);
952}
953
954/// Behaves the same as handleErrors, except that by contract all errors
955/// *must* be handled by the given handlers (i.e. there must be no remaining
956/// errors after running the handlers, or llvm_unreachable is called).
957template <typename... HandlerTs>
958void handleAllErrors(Error E, HandlerTs &&... Handlers) {
959 cantFail(handleErrors(std::move(E), std::forward<HandlerTs>(Handlers)...));
960}
961
962/// Check that E is a non-error, then drop it.
963/// If E is an error, llvm_unreachable will be called.
964inline void handleAllErrors(Error E) {
965 cantFail(std::move(E));
966}
967
968/// Handle any errors (if present) in an Expected<T>, then try a recovery path.
969///
970/// If the incoming value is a success value it is returned unmodified. If it
971/// is a failure value then it the contained error is passed to handleErrors.
972/// If handleErrors is able to handle the error then the RecoveryPath functor
973/// is called to supply the final result. If handleErrors is not able to
974/// handle all errors then the unhandled errors are returned.
975///
976/// This utility enables the follow pattern:
977///
978/// @code{.cpp}
979/// enum FooStrategy { Aggressive, Conservative };
980/// Expected<Foo> foo(FooStrategy S);
981///
982/// auto ResultOrErr =
983/// handleExpected(
984/// foo(Aggressive),
985/// []() { return foo(Conservative); },
986/// [](AggressiveStrategyError&) {
987/// // Implicitly conusme this - we'll recover by using a conservative
988/// // strategy.
989/// });
990///
991/// @endcode
992template <typename T, typename RecoveryFtor, typename... HandlerTs>
993Expected<T> handleExpected(Expected<T> ValOrErr, RecoveryFtor &&RecoveryPath,
994 HandlerTs &&... Handlers) {
995 if (ValOrErr)
996 return ValOrErr;
997
998 if (auto Err = handleErrors(ValOrErr.takeError(),
999 std::forward<HandlerTs>(Handlers)...))
1000 return std::move(Err);
1001
1002 return RecoveryPath();
1003}
1004
1005/// Log all errors (if any) in E to OS. If there are any errors, ErrorBanner
1006/// will be printed before the first one is logged. A newline will be printed
1007/// after each error.
1008///
1009/// This function is compatible with the helpers from Support/WithColor.h. You
1010/// can pass any of them as the OS. Please consider using them instead of
1011/// including 'error: ' in the ErrorBanner.
1012///
1013/// This is useful in the base level of your program to allow clean termination
1014/// (allowing clean deallocation of resources, etc.), while reporting error
1015/// information to the user.
1016void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner = {});
1017
1018/// Write all error messages (if any) in E to a string. The newline character
1019/// is used to separate error messages.
1020inline std::string toString(Error E) {
1021 SmallVector<std::string, 2> Errors;
1022 handleAllErrors(std::move(E), [&Errors](const ErrorInfoBase &EI) {
1023 Errors.push_back(EI.message());
1024 });
1025 return join(Errors.begin(), Errors.end(), "\n");
1026}
1027
1028/// Consume a Error without doing anything. This method should be used
1029/// only where an error can be considered a reasonable and expected return
1030/// value.
1031///
1032/// Uses of this method are potentially indicative of design problems: If it's
1033/// legitimate to do nothing while processing an "error", the error-producer
1034/// might be more clearly refactored to return an Optional<T>.
1035inline void consumeError(Error Err) {
1036 handleAllErrors(std::move(Err), [](const ErrorInfoBase &) {});
1037}
1038
1039/// Convert an Expected to an Optional without doing anything. This method
1040/// should be used only where an error can be considered a reasonable and
1041/// expected return value.
1042///
1043/// Uses of this method are potentially indicative of problems: perhaps the
1044/// error should be propagated further, or the error-producer should just
1045/// return an Optional in the first place.
1046template <typename T> Optional<T> expectedToOptional(Expected<T> &&E) {
1047 if (E)
1048 return std::move(*E);
1049 consumeError(E.takeError());
1050 return None;
1051}
1052
1053/// Helper for converting an Error to a bool.
1054///
1055/// This method returns true if Err is in an error state, or false if it is
1056/// in a success state. Puts Err in a checked state in both cases (unlike
1057/// Error::operator bool(), which only does this for success states).
1058inline bool errorToBool(Error Err) {
1059 bool IsError = static_cast<bool>(Err);
1060 if (IsError)
1061 consumeError(std::move(Err));
1062 return IsError;
1063}
1064
1065/// Helper for Errors used as out-parameters.
1066///
1067/// This helper is for use with the Error-as-out-parameter idiom, where an error
1068/// is passed to a function or method by reference, rather than being returned.
1069/// In such cases it is helpful to set the checked bit on entry to the function
1070/// so that the error can be written to (unchecked Errors abort on assignment)
1071/// and clear the checked bit on exit so that clients cannot accidentally forget
1072/// to check the result. This helper performs these actions automatically using
1073/// RAII:
1074///
1075/// @code{.cpp}
1076/// Result foo(Error &Err) {
1077/// ErrorAsOutParameter ErrAsOutParam(&Err); // 'Checked' flag set
1078/// // <body of foo>
1079/// // <- 'Checked' flag auto-cleared when ErrAsOutParam is destructed.
1080/// }
1081/// @endcode
1082///
1083/// ErrorAsOutParameter takes an Error* rather than Error& so that it can be
1084/// used with optional Errors (Error pointers that are allowed to be null). If
1085/// ErrorAsOutParameter took an Error reference, an instance would have to be
1086/// created inside every condition that verified that Error was non-null. By
1087/// taking an Error pointer we can just create one instance at the top of the
1088/// function.
1089class ErrorAsOutParameter {
1090public:
1091 ErrorAsOutParameter(Error *Err) : Err(Err) {
1092 // Raise the checked bit if Err is success.
1093 if (Err)
1094 (void)!!*Err;
1095 }
1096
1097 ~ErrorAsOutParameter() {
1098 // Clear the checked bit.
1099 if (Err && !*Err)
1100 *Err = Error::success();
1101 }
1102
1103private:
1104 Error *Err;
1105};
1106
1107/// Helper for Expected<T>s used as out-parameters.
1108///
1109/// See ErrorAsOutParameter.
1110template <typename T>
1111class ExpectedAsOutParameter {
1112public:
1113 ExpectedAsOutParameter(Expected<T> *ValOrErr)
1114 : ValOrErr(ValOrErr) {
1115 if (ValOrErr)
1116 (void)!!*ValOrErr;
1117 }
1118
1119 ~ExpectedAsOutParameter() {
1120 if (ValOrErr)
1121 ValOrErr->setUnchecked();
1122 }
1123
1124private:
1125 Expected<T> *ValOrErr;
1126};
1127
1128/// This class wraps a std::error_code in a Error.
1129///
1130/// This is useful if you're writing an interface that returns a Error
1131/// (or Expected) and you want to call code that still returns
1132/// std::error_codes.
1133class ECError : public ErrorInfo<ECError> {
1134 friend Error errorCodeToError(std::error_code);
1135
1136 virtual void anchor() override;
1137
1138public:
1139 void setErrorCode(std::error_code EC) { this->EC = EC; }
1140 std::error_code convertToErrorCode() const override { return EC; }
1141 void log(raw_ostream &OS) const override { OS << EC.message(); }
1142
1143 // Used by ErrorInfo::classID.
1144 static char ID;
1145
1146protected:
1147 ECError() = default;
1148 ECError(std::error_code EC) : EC(EC) {}
1149
1150 std::error_code EC;
1151};
1152
1153/// The value returned by this function can be returned from convertToErrorCode
1154/// for Error values where no sensible translation to std::error_code exists.
1155/// It should only be used in this situation, and should never be used where a
1156/// sensible conversion to std::error_code is available, as attempts to convert
1157/// to/from this error will result in a fatal error. (i.e. it is a programmatic
1158///error to try to convert such a value).
1159std::error_code inconvertibleErrorCode();
1160
1161/// Helper for converting an std::error_code to a Error.
1162Error errorCodeToError(std::error_code EC);
1163
1164/// Helper for converting an ECError to a std::error_code.
1165///
1166/// This method requires that Err be Error() or an ECError, otherwise it
1167/// will trigger a call to abort().
1168std::error_code errorToErrorCode(Error Err);
1169
1170/// Convert an ErrorOr<T> to an Expected<T>.
1171template <typename T> Expected<T> errorOrToExpected(ErrorOr<T> &&EO) {
1172 if (auto EC = EO.getError())
1173 return errorCodeToError(EC);
1174 return std::move(*EO);
1175}
1176
1177/// Convert an Expected<T> to an ErrorOr<T>.
1178template <typename T> ErrorOr<T> expectedToErrorOr(Expected<T> &&E) {
1179 if (auto Err = E.takeError())
1180 return errorToErrorCode(std::move(Err));
1181 return std::move(*E);
1182}
1183
1184/// This class wraps a string in an Error.
1185///
1186/// StringError is useful in cases where the client is not expected to be able
1187/// to consume the specific error message programmatically (for example, if the
1188/// error message is to be presented to the user).
1189///
1190/// StringError can also be used when additional information is to be printed
1191/// along with a error_code message. Depending on the constructor called, this
1192/// class can either display:
1193/// 1. the error_code message (ECError behavior)
1194/// 2. a string
1195/// 3. the error_code message and a string
1196///
1197/// These behaviors are useful when subtyping is required; for example, when a
1198/// specific library needs an explicit error type. In the example below,
1199/// PDBError is derived from StringError:
1200///
1201/// @code{.cpp}
1202/// Expected<int> foo() {
1203/// return llvm::make_error<PDBError>(pdb_error_code::dia_failed_loading,
1204/// "Additional information");
1205/// }
1206/// @endcode
1207///
1208class StringError : public ErrorInfo<StringError> {
1209public:
1210 static char ID;
1211
1212 // Prints EC + S and converts to EC
1213 StringError(std::error_code EC, const Twine &S = Twine());
1214
1215 // Prints S and converts to EC
1216 StringError(const Twine &S, std::error_code EC);
1217
1218 void log(raw_ostream &OS) const override;
1219 std::error_code convertToErrorCode() const override;
1220
1221 const std::string &getMessage() const { return Msg; }
1222
1223private:
1224 std::string Msg;
1225 std::error_code EC;
1226 const bool PrintMsgOnly = false;
1227};
1228
1229/// Create formatted StringError object.
1230template <typename... Ts>
1231inline Error createStringError(std::error_code EC, char const *Fmt,
1232 const Ts &... Vals) {
1233 std::string Buffer;
1234 raw_string_ostream Stream(Buffer);
1235 Stream << format(Fmt, Vals...);
1236 return make_error<StringError>(Stream.str(), EC);
1237}
1238
1239Error createStringError(std::error_code EC, char const *Msg);
1240
1241inline Error createStringError(std::error_code EC, const Twine &S) {
1242 return createStringError(EC, S.str().c_str());
1243}
1244
1245template <typename... Ts>
1246inline Error createStringError(std::errc EC, char const *Fmt,
1247 const Ts &... Vals) {
1248 return createStringError(std::make_error_code(EC), Fmt, Vals...);
1249}
1250
1251/// This class wraps a filename and another Error.
1252///
1253/// In some cases, an error needs to live along a 'source' name, in order to
1254/// show more detailed information to the user.
1255class FileError final : public ErrorInfo<FileError> {
1256
1257 friend Error createFileError(const Twine &, Error);
1258 friend Error createFileError(const Twine &, size_t, Error);
1259
1260public:
1261 void log(raw_ostream &OS) const override {
1262 assert(Err && !FileName.empty() && "Trying to log after takeError().")(static_cast<void> (0));
1263 OS << "'" << FileName << "': ";
1264 if (Line.hasValue())
1265 OS << "line " << Line.getValue() << ": ";
1266 Err->log(OS);
1267 }
1268
1269 StringRef getFileName() { return FileName; }
1270
1271 Error takeError() { return Error(std::move(Err)); }
1272
1273 std::error_code convertToErrorCode() const override;
1274
1275 // Used by ErrorInfo::classID.
1276 static char ID;
1277
1278private:
1279 FileError(const Twine &F, Optional<size_t> LineNum,
1280 std::unique_ptr<ErrorInfoBase> E) {
1281 assert(E && "Cannot create FileError from Error success value.")(static_cast<void> (0));
1282 assert(!F.isTriviallyEmpty() &&(static_cast<void> (0))
1283 "The file name provided to FileError must not be empty.")(static_cast<void> (0));
1284 FileName = F.str();
1285 Err = std::move(E);
1286 Line = std::move(LineNum);
1287 }
1288
1289 static Error build(const Twine &F, Optional<size_t> Line, Error E) {
1290 std::unique_ptr<ErrorInfoBase> Payload;
1291 handleAllErrors(std::move(E),
1292 [&](std::unique_ptr<ErrorInfoBase> EIB) -> Error {
1293 Payload = std::move(EIB);
1294 return Error::success();
1295 });
1296 return Error(
1297 std::unique_ptr<FileError>(new FileError(F, Line, std::move(Payload))));
1298 }
1299
1300 std::string FileName;
1301 Optional<size_t> Line;
1302 std::unique_ptr<ErrorInfoBase> Err;
1303};
1304
1305/// Concatenate a source file path and/or name with an Error. The resulting
1306/// Error is unchecked.
1307inline Error createFileError(const Twine &F, Error E) {
1308 return FileError::build(F, Optional<size_t>(), std::move(E));
1309}
1310
1311/// Concatenate a source file path and/or name with line number and an Error.
1312/// The resulting Error is unchecked.
1313inline Error createFileError(const Twine &F, size_t Line, Error E) {
1314 return FileError::build(F, Optional<size_t>(Line), std::move(E));
1315}
1316
1317/// Concatenate a source file path and/or name with a std::error_code
1318/// to form an Error object.
1319inline Error createFileError(const Twine &F, std::error_code EC) {
1320 return createFileError(F, errorCodeToError(EC));
1321}
1322
1323/// Concatenate a source file path and/or name with line number and
1324/// std::error_code to form an Error object.
1325inline Error createFileError(const Twine &F, size_t Line, std::error_code EC) {
1326 return createFileError(F, Line, errorCodeToError(EC));
1327}
1328
1329Error createFileError(const Twine &F, ErrorSuccess) = delete;
1330
1331/// Helper for check-and-exit error handling.
1332///
1333/// For tool use only. NOT FOR USE IN LIBRARY CODE.
1334///
1335class ExitOnError {
1336public:
1337 /// Create an error on exit helper.
1338 ExitOnError(std::string Banner = "", int DefaultErrorExitCode = 1)
1339 : Banner(std::move(Banner)),
1340 GetExitCode([=](const Error &) { return DefaultErrorExitCode; }) {}
1341
1342 /// Set the banner string for any errors caught by operator().
1343 void setBanner(std::string Banner) { this->Banner = std::move(Banner); }
1344
1345 /// Set the exit-code mapper function.
1346 void setExitCodeMapper(std::function<int(const Error &)> GetExitCode) {
1347 this->GetExitCode = std::move(GetExitCode);
1348 }
1349
1350 /// Check Err. If it's in a failure state log the error(s) and exit.
1351 void operator()(Error Err) const { checkError(std::move(Err)); }
1352
1353 /// Check E. If it's in a success state then return the contained value. If
1354 /// it's in a failure state log the error(s) and exit.
1355 template <typename T> T operator()(Expected<T> &&E) const {
1356 checkError(E.takeError());
1357 return std::move(*E);
1358 }
1359
1360 /// Check E. If it's in a success state then return the contained reference. If
1361 /// it's in a failure state log the error(s) and exit.
1362 template <typename T> T& operator()(Expected<T&> &&E) const {
1363 checkError(E.takeError());
1364 return *E;
1365 }
1366
1367private:
1368 void checkError(Error Err) const {
1369 if (Err) {
1370 int ExitCode = GetExitCode(Err);
1371 logAllUnhandledErrors(std::move(Err), errs(), Banner);
1372 exit(ExitCode);
1373 }
1374 }
1375
1376 std::string Banner;
1377 std::function<int(const Error &)> GetExitCode;
1378};
1379
1380/// Conversion from Error to LLVMErrorRef for C error bindings.
1381inline LLVMErrorRef wrap(Error Err) {
1382 return reinterpret_cast<LLVMErrorRef>(Err.takePayload().release());
1383}
1384
1385/// Conversion from LLVMErrorRef to Error for C error bindings.
1386inline Error unwrap(LLVMErrorRef ErrRef) {
1387 return Error(std::unique_ptr<ErrorInfoBase>(
1388 reinterpret_cast<ErrorInfoBase *>(ErrRef)));
1389}
1390
1391} // end namespace llvm
1392
1393#endif // LLVM_SUPPORT_ERROR_H