Auto merge of #122117 - matthiaskrgr:rollup-3yrv3j6, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #122015 (Add better explanation for `rustc_index::IndexVec`)
 - #122061 (Clarify FatalErrorHandler)
 - #122062 (Explicitly assign constructed C++ classes)
 - #122072 (Refer to "slice" instead of "vector" in Ord and PartialOrd trait impl of slices)
 - #122088 (Remove unnecessary fixme on new thread stack size)
 - #122094 (Remove outdated footnote "missing-stack-probe" in platform-support)
 - #122107 (Temporarily make allow-by-default the `non_local_definitions` lint)
 - #122109 (compiletest: Add a `//@ needs-threads` directive)

Failed merges:

 - #122104 (Rust is a proper name: rust → Rust)

r? `@ghost`
`@rustbot` modify labels: rollup

4 files changed, 65 insertions, 54 deletions

diff --git a/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
index 627be997513..60789b07e54 100644
--- a/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
@@ -120,7 +120,7 @@ extern "C" void LLVMRustCoverageWriteFilenamesSectionToBuffer(
   }
   auto FilenamesWriter =
       coverage::CoverageFilenamesSectionWriter(ArrayRef<std::string>(FilenameRefs));
-  RawRustStringOstream OS(BufferOut);
+  auto OS = RawRustStringOstream(BufferOut);
   FilenamesWriter.write(OS);
 }
 
@@ -160,7 +160,7 @@ extern "C" void LLVMRustCoverageWriteMappingToBuffer(
       ArrayRef<unsigned>(VirtualFileMappingIDs, NumVirtualFileMappingIDs),
       Expressions,
       MappingRegions);
-  RawRustStringOstream OS(BufferOut);
+  auto OS = RawRustStringOstream(BufferOut);
   CoverageMappingWriter.write(OS);
 }
 
@@ -168,23 +168,23 @@ extern "C" LLVMValueRef LLVMRustCoverageCreatePGOFuncNameVar(
     LLVMValueRef F,
     const char *FuncName,
     size_t FuncNameLen) {
-  StringRef FuncNameRef(FuncName, FuncNameLen);
+  auto FuncNameRef = StringRef(FuncName, FuncNameLen);
   return wrap(createPGOFuncNameVar(*cast<Function>(unwrap(F)), FuncNameRef));
 }
 
 extern "C" uint64_t LLVMRustCoverageHashByteArray(
     const char *Bytes,
     size_t NumBytes) {
-  StringRef StrRef(Bytes, NumBytes);
+  auto StrRef = StringRef(Bytes, NumBytes);
   return IndexedInstrProf::ComputeHash(StrRef);
 }
 
 static void WriteSectionNameToString(LLVMModuleRef M,
                                      InstrProfSectKind SK,
                                      RustStringRef Str) {
-  Triple TargetTriple(unwrap(M)->getTargetTriple());
+  auto TargetTriple = Triple(unwrap(M)->getTargetTriple());
   auto name = getInstrProfSectionName(SK, TargetTriple.getObjectFormat());
-  RawRustStringOstream OS(Str);
+  auto OS = RawRustStringOstream(Str);
   OS << name;
 }
 
@@ -200,7 +200,7 @@ extern "C" void LLVMRustCoverageWriteFuncSectionNameToString(LLVMModuleRef M,
 
 extern "C" void LLVMRustCoverageWriteMappingVarNameToString(RustStringRef Str) {
   auto name = getCoverageMappingVarName();
-  RawRustStringOstream OS(Str);
+  auto OS = RawRustStringOstream(Str);
   OS << name;
 }
 
diff --git a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
index 4ec784e2590..1cdfc22431e 100644
--- a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
@@ -77,9 +77,9 @@ extern "C" void LLVMRustTimeTraceProfilerFinishThread() {
 }
 
 extern "C" void LLVMRustTimeTraceProfilerFinish(const char* FileName) {
-  StringRef FN(FileName);
+  auto FN = StringRef(FileName);
   std::error_code EC;
-  raw_fd_ostream OS(FN, EC, sys::fs::CD_CreateAlways);
+  auto OS = raw_fd_ostream(FN, EC, sys::fs::CD_CreateAlways);
 
   timeTraceProfilerWrite(OS);
   timeTraceProfilerCleanup();
@@ -424,7 +424,7 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
   auto CM = fromRust(RustCM);
 
   std::string Error;
-  Triple Trip(Triple::normalize(TripleStr));
+  auto Trip = Triple(Triple::normalize(TripleStr));
   const llvm::Target *TheTarget =
       TargetRegistry::lookupTarget(Trip.getTriple(), Error);
   if (TheTarget == nullptr) {
@@ -537,8 +537,8 @@ extern "C" void LLVMRustDisposeTargetMachine(LLVMTargetMachineRef TM) {
 // TargetLibraryInfo pass, so we use this method to do so.
 extern "C" void LLVMRustAddLibraryInfo(LLVMPassManagerRef PMR, LLVMModuleRef M,
                                        bool DisableSimplifyLibCalls) {
-  Triple TargetTriple(unwrap(M)->getTargetTriple());
-  TargetLibraryInfoImpl TLII(TargetTriple);
+  auto TargetTriple = Triple(unwrap(M)->getTargetTriple());
+  auto TLII = TargetLibraryInfoImpl(TargetTriple);
   if (DisableSimplifyLibCalls)
     TLII.disableAllFunctions();
   unwrap(PMR)->add(new TargetLibraryInfoWrapperPass(TLII));
@@ -589,7 +589,7 @@ LLVMRustWriteOutputFile(LLVMTargetMachineRef Target, LLVMPassManagerRef PMR,
 
   std::string ErrorInfo;
   std::error_code EC;
-  raw_fd_ostream OS(Path, EC, sys::fs::OF_None);
+  auto OS = raw_fd_ostream(Path, EC, sys::fs::OF_None);
   if (EC)
     ErrorInfo = EC.message();
   if (ErrorInfo != "") {
@@ -597,9 +597,9 @@ LLVMRustWriteOutputFile(LLVMTargetMachineRef Target, LLVMPassManagerRef PMR,
     return LLVMRustResult::Failure;
   }
 
-  buffer_ostream BOS(OS);
+  auto BOS = buffer_ostream(OS);
   if (DwoPath) {
-    raw_fd_ostream DOS(DwoPath, EC, sys::fs::OF_None);
+    auto DOS = raw_fd_ostream(DwoPath, EC, sys::fs::OF_None);
     EC.clear();
     if (EC)
         ErrorInfo = EC.message();
@@ -607,7 +607,7 @@ LLVMRustWriteOutputFile(LLVMTargetMachineRef Target, LLVMPassManagerRef PMR,
       LLVMRustSetLastError(ErrorInfo.c_str());
       return LLVMRustResult::Failure;
     }
-    buffer_ostream DBOS(DOS);
+    auto DBOS = buffer_ostream(DOS);
     unwrap(Target)->addPassesToEmitFile(*PM, BOS, &DBOS, FileType, false);
     PM->run(*unwrap(M));
   } else {
@@ -796,7 +796,7 @@ LLVMRustOptimize(
                         DebugInfoForProfiling);
   }
 
-  PassBuilder PB(TM, PTO, PGOOpt, &PIC);
+  auto PB = PassBuilder(TM, PTO, PGOOpt, &PIC);
   LoopAnalysisManager LAM;
   FunctionAnalysisManager FAM;
   CGSCCAnalysisManager CGAM;
@@ -1112,7 +1112,7 @@ extern "C" LLVMRustResult
 LLVMRustPrintModule(LLVMModuleRef M, const char *Path, DemangleFn Demangle) {
   std::string ErrorInfo;
   std::error_code EC;
-  raw_fd_ostream OS(Path, EC, sys::fs::OF_None);
+  auto OS = raw_fd_ostream(Path, EC, sys::fs::OF_None);
   if (EC)
     ErrorInfo = EC.message();
   if (ErrorInfo != "") {
@@ -1120,8 +1120,8 @@ LLVMRustPrintModule(LLVMModuleRef M, const char *Path, DemangleFn Demangle) {
     return LLVMRustResult::Failure;
   }
 
-  RustAssemblyAnnotationWriter AAW(Demangle);
-  formatted_raw_ostream FOS(OS);
+  auto AAW = RustAssemblyAnnotationWriter(Demangle);
+  auto FOS = formatted_raw_ostream(OS);
   unwrap(M)->print(FOS, &AAW);
 
   return LLVMRustResult::Success;
@@ -1281,8 +1281,8 @@ LLVMRustCreateThinLTOData(LLVMRustThinLTOModule *modules,
   // Load each module's summary and merge it into one combined index
   for (int i = 0; i < num_modules; i++) {
     auto module = &modules[i];
-    StringRef buffer(module->data, module->len);
-    MemoryBufferRef mem_buffer(buffer, module->identifier);
+    auto buffer = StringRef(module->data, module->len);
+    auto mem_buffer = MemoryBufferRef(buffer, module->identifier);
 
     Ret->ModuleMap[module->identifier] = mem_buffer;
 
@@ -1485,7 +1485,7 @@ LLVMRustPrepareThinLTOImport(const LLVMRustThinLTOData *Data, LLVMModuleRef M,
     return MOrErr;
   };
   bool ClearDSOLocal = clearDSOLocalOnDeclarations(Mod, Target);
-  FunctionImporter Importer(Data->Index, Loader, ClearDSOLocal);
+  auto Importer = FunctionImporter(Data->Index, Loader, ClearDSOLocal);
   Expected<bool> Result = Importer.importFunctions(Mod, ImportList);
   if (!Result) {
     LLVMRustSetLastError(toString(Result.takeError()).c_str());
@@ -1510,7 +1510,7 @@ extern "C" LLVMRustThinLTOBuffer*
 LLVMRustThinLTOBufferCreate(LLVMModuleRef M, bool is_thin) {
   auto Ret = std::make_unique<LLVMRustThinLTOBuffer>();
   {
-    raw_string_ostream OS(Ret->data);
+    auto OS = raw_string_ostream(Ret->data);
     {
       if (is_thin) {
         PassBuilder PB;
@@ -1557,8 +1557,8 @@ LLVMRustParseBitcodeForLTO(LLVMContextRef Context,
                            const char *data,
                            size_t len,
                            const char *identifier) {
-  StringRef Data(data, len);
-  MemoryBufferRef Buffer(Data, identifier);
+  auto Data = StringRef(data, len);
+  auto Buffer = MemoryBufferRef(Data, identifier);
   unwrap(Context)->enableDebugTypeODRUniquing();
   Expected<std::unique_ptr<Module>> SrcOrError =
       parseBitcodeFile(Buffer, *unwrap(Context));
@@ -1576,8 +1576,8 @@ extern "C" const char *LLVMRustGetSliceFromObjectDataByName(const char *data,
                                                             const char *name,
                                                             size_t *out_len) {
   *out_len = 0;
-  StringRef Data(data, len);
-  MemoryBufferRef Buffer(Data, ""); // The id is unused.
+  auto Data = StringRef(data, len);
+  auto Buffer = MemoryBufferRef(Data, ""); // The id is unused.
   file_magic Type = identify_magic(Buffer.getBuffer());
   Expected<std::unique_ptr<object::ObjectFile>> ObjFileOrError =
       object::ObjectFile::createObjectFile(Buffer, Type);
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index cb7cce4da0d..d9262a92782 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -66,12 +66,22 @@ static LLVM_THREAD_LOCAL char *LastError;
 static void FatalErrorHandler(void *UserData,
                               const char* Reason,
                               bool GenCrashDiag) {
-  // Do the same thing that the default error handler does.
-  std::cerr << "LLVM ERROR: " << Reason << std::endl;
+  // Once upon a time we emitted "LLVM ERROR:" specifically to mimic LLVM. Then,
+  // we developed crater and other tools which only expose logs, not error codes.
+  // Use a more greppable prefix that will still match the "LLVM ERROR:" prefix.
+  std::cerr << "rustc-LLVM ERROR: " << Reason << std::endl;
 
   // Since this error handler exits the process, we have to run any cleanup that
   // LLVM would run after handling the error. This might change with an LLVM
   // upgrade.
+  //
+  // In practice, this will do nothing, because the only cleanup LLVM does is
+  // to remove all files that were registered with it via a frontend calling
+  // one of the `createOutputFile` family of functions in LLVM and passing true
+  // to RemoveFileOnSignal, something that rustc does not do. However, it would
+  // be... inadvisable to suddenly stop running these handlers, if LLVM gets
+  // "interesting" ideas in the future about what cleanup should be done.
+  // We might even find it useful for generating less artifacts.
   sys::RunInterruptHandlers();
 
   exit(101);
@@ -109,7 +119,7 @@ extern "C" void LLVMRustSetNormalizedTarget(LLVMModuleRef M,
 
 extern "C" const char *LLVMRustPrintPassTimings(size_t *Len) {
   std::string buf;
-  raw_string_ostream SS(buf);
+  auto SS = raw_string_ostream(buf);
   TimerGroup::printAll(SS);
   SS.flush();
   *Len = buf.length();
@@ -120,7 +130,7 @@ extern "C" const char *LLVMRustPrintPassTimings(size_t *Len) {
 
 extern "C" const char *LLVMRustPrintStatistics(size_t *Len) {
   std::string buf;
-  raw_string_ostream SS(buf);
+  auto SS = raw_string_ostream(buf);
   llvm::PrintStatistics(SS);
   SS.flush();
   *Len = buf.length();
@@ -174,7 +184,7 @@ extern "C" LLVMValueRef LLVMRustGetOrInsertFunction(LLVMModuleRef M,
 extern "C" LLVMValueRef
 LLVMRustGetOrInsertGlobal(LLVMModuleRef M, const char *Name, size_t NameLen, LLVMTypeRef Ty) {
   Module *Mod = unwrap(M);
-  StringRef NameRef(Name, NameLen);
+  auto NameRef = StringRef(Name, NameLen);
 
   // We don't use Module::getOrInsertGlobal because that returns a Constant*,
   // which may either be the real GlobalVariable*, or a constant bitcast of it
@@ -285,7 +295,7 @@ static Attribute::AttrKind fromRust(LLVMRustAttribute Kind) {
 template<typename T> static inline void AddAttributes(T *t, unsigned Index,
                                                       LLVMAttributeRef *Attrs, size_t AttrsLen) {
   AttributeList PAL = t->getAttributes();
-  AttrBuilder B(t->getContext());
+  auto B = AttrBuilder(t->getContext());
   for (LLVMAttributeRef Attr : ArrayRef<LLVMAttributeRef>(Attrs, AttrsLen))
     B.addAttribute(unwrap(Attr));
   AttributeList PALNew = PAL.addAttributesAtIndex(t->getContext(), Index, B);
@@ -1195,13 +1205,13 @@ extern "C" int64_t LLVMRustDIBuilderCreateOpLLVMFragment() {
 }
 
 extern "C" void LLVMRustWriteTypeToString(LLVMTypeRef Ty, RustStringRef Str) {
-  RawRustStringOstream OS(Str);
+  auto OS = RawRustStringOstream(Str);
   unwrap<llvm::Type>(Ty)->print(OS);
 }
 
 extern "C" void LLVMRustWriteValueToString(LLVMValueRef V,
                                            RustStringRef Str) {
-  RawRustStringOstream OS(Str);
+  auto OS = RawRustStringOstream(Str);
   if (!V) {
     OS << "(null)";
   } else {
@@ -1224,7 +1234,7 @@ extern "C" LLVMTypeRef LLVMRustArrayType(LLVMTypeRef ElementTy,
 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(Twine, LLVMTwineRef)
 
 extern "C" void LLVMRustWriteTwineToString(LLVMTwineRef T, RustStringRef Str) {
-  RawRustStringOstream OS(Str);
+  auto OS = RawRustStringOstream(Str);
   unwrap(T)->print(OS);
 }
 
@@ -1236,11 +1246,11 @@ extern "C" void LLVMRustUnpackOptimizationDiagnostic(
   llvm::DiagnosticInfoOptimizationBase *Opt =
       static_cast<llvm::DiagnosticInfoOptimizationBase *>(unwrap(DI));
 
-  RawRustStringOstream PassNameOS(PassNameOut);
+  auto PassNameOS = RawRustStringOstream(PassNameOut);
   PassNameOS << Opt->getPassName();
   *FunctionOut = wrap(&Opt->getFunction());
 
-  RawRustStringOstream FilenameOS(FilenameOut);
+  auto FilenameOS = RawRustStringOstream(FilenameOut);
   DiagnosticLocation loc = Opt->getLocation();
   if (loc.isValid()) {
     *Line = loc.getLine();
@@ -1248,7 +1258,7 @@ extern "C" void LLVMRustUnpackOptimizationDiagnostic(
     FilenameOS << loc.getAbsolutePath();
   }
 
-  RawRustStringOstream MessageOS(MessageOut);
+  auto MessageOS = RawRustStringOstream(MessageOut);
   MessageOS << Opt->getMsg();
 }
 
@@ -1291,8 +1301,8 @@ LLVMRustUnpackInlineAsmDiagnostic(LLVMDiagnosticInfoRef DI,
 
 extern "C" void LLVMRustWriteDiagnosticInfoToString(LLVMDiagnosticInfoRef DI,
                                                     RustStringRef Str) {
-  RawRustStringOstream OS(Str);
-  DiagnosticPrinterRawOStream DP(OS);
+  auto OS = RawRustStringOstream(Str);
+  auto DP = DiagnosticPrinterRawOStream(OS);
   unwrap(DI)->print(DP);
 }
 
@@ -1406,7 +1416,7 @@ extern "C" LLVMTypeKind LLVMRustGetTypeKind(LLVMTypeRef Ty) {
   default:
     {
       std::string error;
-      llvm::raw_string_ostream stream(error);
+      auto stream = llvm::raw_string_ostream(error);
       stream << "Rust does not support the TypeID: " << unwrap(Ty)->getTypeID()
              << " for the type: " << *unwrap(Ty);
       stream.flush();
@@ -1432,7 +1442,7 @@ extern "C" bool LLVMRustUnpackSMDiagnostic(LLVMSMDiagnosticRef DRef,
                                            unsigned* RangesOut,
                                            size_t* NumRanges) {
   SMDiagnostic& D = *unwrap(DRef);
-  RawRustStringOstream MessageOS(MessageOut);
+  auto MessageOS = RawRustStringOstream(MessageOut);
   MessageOS << D.getMessage();
 
   switch (D.getKind()) {
@@ -1547,7 +1557,7 @@ extern "C" void LLVMRustPositionBuilderAtStart(LLVMBuilderRef B,
 
 extern "C" void LLVMRustSetComdat(LLVMModuleRef M, LLVMValueRef V,
                                   const char *Name, size_t NameLen) {
-  Triple TargetTriple(unwrap(M)->getTargetTriple());
+  Triple TargetTriple = Triple(unwrap(M)->getTargetTriple());
   GlobalObject *GV = unwrap<GlobalObject>(V);
   if (TargetTriple.supportsCOMDAT()) {
     StringRef NameRef(Name, NameLen);
@@ -1711,7 +1721,7 @@ extern "C" LLVMRustModuleBuffer*
 LLVMRustModuleBufferCreate(LLVMModuleRef M) {
   auto Ret = std::make_unique<LLVMRustModuleBuffer>();
   {
-    raw_string_ostream OS(Ret->data);
+    auto OS = raw_string_ostream(Ret->data);
     WriteBitcodeToFile(*unwrap(M), OS);
   }
   return Ret.release();
@@ -1741,8 +1751,8 @@ LLVMRustModuleCost(LLVMModuleRef M) {
 extern "C" void
 LLVMRustModuleInstructionStats(LLVMModuleRef M, RustStringRef Str)
 {
-  RawRustStringOstream OS(Str);
-  llvm::json::OStream JOS(OS);
+  auto OS = RawRustStringOstream(Str);
+  auto JOS = llvm::json::OStream(OS);
   auto Module = unwrap(M);
 
   JOS.object([&] {
@@ -1857,7 +1867,7 @@ extern "C" LLVMRustResult LLVMRustWriteImportLibrary(
     MinGW);
   if (Error) {
     std::string errorString;
-    llvm::raw_string_ostream stream(errorString);
+    auto stream = llvm::raw_string_ostream(errorString);
     stream << Error;
     stream.flush();
     LLVMRustSetLastError(errorString.c_str());
@@ -2041,7 +2051,7 @@ extern "C" void LLVMRustContextConfigureDiagnosticHandler(
 }
 
 extern "C" void LLVMRustGetMangledName(LLVMValueRef V, RustStringRef Str) {
-  RawRustStringOstream OS(Str);
+  auto OS = RawRustStringOstream(Str);
   GlobalValue *GV = unwrap<GlobalValue>(V);
   Mangler().getNameWithPrefix(OS, GV, true);
 }
diff --git a/compiler/rustc_llvm/llvm-wrapper/SymbolWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/SymbolWrapper.cpp
index 91f84692df8..ee8239ef8e7 100644
--- a/compiler/rustc_llvm/llvm-wrapper/SymbolWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/SymbolWrapper.cpp
@@ -11,6 +11,7 @@
 #include "llvm/ADT/SmallString.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/Object/ObjectFile.h"
+#include <llvm/Support/raw_ostream.h>
 
 using namespace llvm;
 using namespace llvm::sys;
@@ -42,7 +43,7 @@ extern "C" void *LLVMRustGetSymbols(
     MemoryBuffer::getMemBuffer(StringRef(BufPtr, BufLen), StringRef("LLVMRustGetSymbolsObject"),
                                false);
   SmallString<0> SymNameBuf;
-  raw_svector_ostream SymName(SymNameBuf);
+  auto SymName = raw_svector_ostream(SymNameBuf);
 
   // In the scenario when LLVMContext is populated SymbolicFile will contain a
   // reference to it, thus SymbolicFile should be destroyed first.
@@ -60,7 +61,7 @@ extern "C" void *LLVMRustGetSymbols(
     if (!ObjOrErr) {
       Error E = ObjOrErr.takeError();
       SmallString<0> ErrorBuf;
-      raw_svector_ostream Error(ErrorBuf);
+      auto Error = raw_svector_ostream(ErrorBuf);
       Error << E << '\0';
       return ErrorCallback(Error.str().data());
     }
@@ -70,7 +71,7 @@ extern "C" void *LLVMRustGetSymbols(
     if (!ObjOrErr) {
       Error E = ObjOrErr.takeError();
       SmallString<0> ErrorBuf;
-      raw_svector_ostream Error(ErrorBuf);
+      auto Error = raw_svector_ostream(ErrorBuf);
       Error << E << '\0';
       return ErrorCallback(Error.str().data());
     }
@@ -83,7 +84,7 @@ extern "C" void *LLVMRustGetSymbols(
       continue;
     if (Error E = S.printName(SymName)) {
       SmallString<0> ErrorBuf;
-      raw_svector_ostream Error(ErrorBuf);
+      auto Error = raw_svector_ostream(ErrorBuf);
       Error << E << '\0';
       return ErrorCallback(Error.str().data());
     }