llvm · jurahul · Oct 18, 2025
diff --git a/llvm/include/llvm/Analysis/BlockFrequencyInfoImpl.h b/llvm/include/llvm/Analysis/BlockFrequencyInfoImpl.h
@@ -1813,7 +1813,6 @@ struct BFIDOTGraphTraitsBase : public DefaultDOTGraphTraits {
 
     raw_string_ostream OS(Result);
     OS << "color=\"red\"";
-    OS.flush();
     return Result;
   }
 
@@ -1872,8 +1871,6 @@ struct BFIDOTGraphTraitsBase : public DefaultDOTGraphTraits {
         OS << ",color=\"red\"";
       }
     }
-
-    OS.flush();
     return Str;
   }
 };

diff --git a/llvm/include/llvm/Analysis/LazyCallGraph.h b/llvm/include/llvm/Analysis/LazyCallGraph.h
@@ -513,7 +513,6 @@ class LazyCallGraph {
       std::string Name;
       raw_string_ostream OS(Name);
       OS << *this;
-      OS.flush();
       return Name;
     }
   };
@@ -654,7 +653,6 @@ class LazyCallGraph {
       std::string Name;
       raw_string_ostream OS(Name);
       OS << *this;
-      OS.flush();
       return Name;
     }
 

diff --git a/llvm/include/llvm/Support/FormatVariadic.h b/llvm/include/llvm/Support/FormatVariadic.h
@@ -105,7 +105,6 @@ class formatv_object_base {
     std::string Result;
     raw_string_ostream Stream(Result);
     Stream << *this;
-    Stream.flush();
     return Result;
   }
 

diff --git a/llvm/include/llvm/Support/InterleavedRange.h b/llvm/include/llvm/Support/InterleavedRange.h
@@ -56,7 +56,6 @@ template <typename Range> class InterleavedRange {
     std::string Result;
     raw_string_ostream Stream(Result);
     Stream << *this;
-    Stream.flush();
     return Result;
   }
 

diff --git a/llvm/include/llvm/Support/raw_ostream.h b/llvm/include/llvm/Support/raw_ostream.h
@@ -682,6 +682,8 @@ class LLVM_ABI raw_string_ostream : public raw_ostream {
   void reserveExtraSpace(uint64_t ExtraSize) override {
     OS.reserve(tell() + ExtraSize);
   }
+
+  // void flush() = delete;
 };
 
 /// A raw_ostream that writes to an SmallVector or SmallString.  This is a

diff --git a/llvm/lib/Analysis/ImportedFunctionsInliningStatistics.cpp b/llvm/lib/Analysis/ImportedFunctionsInliningStatistics.cpp
@@ -167,7 +167,6 @@ void ImportedFunctionsInliningStatistics::dump(const bool Verbose) {
                  "non-imported functions inlined into importing module",
                  InlinedNotImportedFunctionsToImportingModuleCount,
                  NotImportedFuncCount, "non-imported functions");
-  Ostream.flush();
   dbgs() << Out;
 }
 

diff --git a/llvm/lib/CodeGen/MIRCanonicalizerPass.cpp b/llvm/lib/CodeGen/MIRCanonicalizerPass.cpp
@@ -96,7 +96,6 @@ rescheduleLexographically(std::vector<MachineInstr *> instructions,
     std::string S;
     raw_string_ostream OS(S);
     II->print(OS);
-    OS.flush();
 
     // Trim the assignment, or start from the beginning in the case of a store.
     const size_t i = S.find('=');

diff --git a/llvm/lib/CodeGen/MachineBlockPlacement.cpp b/llvm/lib/CodeGen/MachineBlockPlacement.cpp
@@ -700,7 +700,6 @@ static std::string getBlockName(const MachineBasicBlock *BB) {
   raw_string_ostream OS(Result);
   OS << printMBBReference(*BB);
   OS << " ('" << BB->getName() << "')";
-  OS.flush();
   return Result;
 }
 #endif

diff --git a/llvm/lib/CodeGen/ModuloSchedule.cpp b/llvm/lib/CodeGen/ModuloSchedule.cpp
@@ -2033,7 +2033,6 @@ void PeelingModuloScheduleExpander::validateAgainstModuloScheduleExpander() {
   std::string ScheduleDump;
   raw_string_ostream OS(ScheduleDump);
   Schedule.print(OS);
-  OS.flush();
 
   // First, run the normal ModuleScheduleExpander. We don't support any
   // InstrChanges.

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -1953,7 +1953,6 @@ void TargetLoweringObjectFileCOFF::emitLinkerDirectives(
     raw_string_ostream OS(Flags);
     emitLinkerFlagsForGlobalCOFF(OS, &GV, getContext().getTargetTriple(),
                                  getMangler());
-    OS.flush();
     if (!Flags.empty()) {
       Streamer.switchSection(getDrectveSection());
       Streamer.emitBytes(Flags);
@@ -1978,7 +1977,6 @@ void TargetLoweringObjectFileCOFF::emitLinkerDirectives(
         raw_string_ostream OS(Flags);
         emitLinkerFlagsForUsedCOFF(OS, GV, getContext().getTargetTriple(),
                                    getMangler());
-        OS.flush();
 
         if (!Flags.empty()) {
           Streamer.switchSection(getDrectveSection());

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp b/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
@@ -234,7 +234,6 @@ bool DWARFVerifier::verifyName(const DWARFDie &Die) {
   raw_string_ostream OS(ReconstructedName);
   std::string OriginalFullName;
   Die.getFullName(OS, &OriginalFullName);
-  OS.flush();
   if (OriginalFullName.empty() || OriginalFullName == ReconstructedName)
     return false;
 

diff --git a/llvm/lib/DebugInfo/GSYM/GsymCreator.cpp b/llvm/lib/DebugInfo/GSYM/GsymCreator.cpp
@@ -564,7 +564,6 @@ llvm::Error GsymCreator::saveSegments(StringRef Path,
       std::optional<uint64_t> FirstFuncAddr = GC->getFirstFunctionAddress();
       if (FirstFuncAddr) {
         SGP << Path << "-" << llvm::format_hex(*FirstFuncAddr, 1);
-        SGP.flush();
         Err = GC->save(SegmentedGsymPath, ByteOrder, std::nullopt);
         if (Err)
           return Err;

diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
@@ -544,7 +544,6 @@ std::string Attribute::getAsString(bool InAttrGrp) const {
     Result += '(';
     raw_string_ostream OS(Result);
     getValueAsType()->print(OS, false, true);
-    OS.flush();
     Result += ')';
     return Result;
   }
@@ -660,7 +659,6 @@ std::string Attribute::getAsString(bool InAttrGrp) const {
       OS << getModRefStr(MR);
     }
     OS << ")";
-    OS.flush();
     return Result;
   }
 
@@ -686,7 +684,6 @@ std::string Attribute::getAsString(bool InAttrGrp) const {
     OS << "i" << CR.getBitWidth() << " ";
     OS << CR.getLower() << ", " << CR.getUpper();
     OS << ")";
-    OS.flush();
     return Result;
   }
 
@@ -697,7 +694,6 @@ std::string Attribute::getAsString(bool InAttrGrp) const {
     OS << "initializes(";
     CRL.print(OS);
     OS << ")";
-    OS.flush();
     return Result;
   }
 

@@ -245,7 +245,6 @@ char *LLVMGetDiagInfoDescription(LLVMDiagnosticInfoRef DI) {
   DiagnosticPrinterRawOStream DP(Stream);
 
   unwrap(DI)->print(DP);
-  Stream.flush();
 
   return LLVMCreateMessage(MsgStorage.c_str());
 }
@@ -473,7 +472,6 @@ char *LLVMPrintModuleToString(LLVMModuleRef M) {
   raw_string_ostream os(buf);
 
   unwrap(M)->print(os, nullptr);
-  os.flush();
 
   return strdup(buf.c_str());
 }
@@ -651,8 +649,6 @@ char *LLVMPrintTypeToString(LLVMTypeRef Ty) {
   else
     os << "Printing <null> Type";
 
-  os.flush();
-
   return strdup(buf.c_str());
 }
 
@@ -1046,8 +1042,6 @@ char* LLVMPrintValueToString(LLVMValueRef Val) {
   else
     os << "Printing <null> Value";
 
-  os.flush();
-
   return strdup(buf.c_str());
 }
 
@@ -1064,8 +1058,6 @@ char *LLVMPrintDbgRecordToString(LLVMDbgRecordRef Record) {
   else
     os << "Printing <null> DbgRecord";
 
-  os.flush();
-
   return strdup(buf.c_str());
 }
 

diff --git a/llvm/lib/IR/DiagnosticInfo.cpp b/llvm/lib/IR/DiagnosticInfo.cpp
@@ -417,7 +417,6 @@ void DiagnosticInfoUnsupported::print(DiagnosticPrinter &DP) const {
 
   OS << getLocationStr() << ": in function " << getFunction().getName() << ' '
      << *getFunction().getFunctionType() << ": " << Msg << '\n';
-  OS.flush();
   DP << Str;
 }
 

diff --git a/llvm/lib/IR/Mangler.cpp b/llvm/lib/IR/Mangler.cpp
@@ -227,7 +227,6 @@ void llvm::emitLinkerFlagsForGlobalCOFF(raw_ostream &OS, const GlobalValue *GV,
       std::string Flag;
       raw_string_ostream FlagOS(Flag);
       Mangler.getNameWithPrefix(FlagOS, GV, false);
-      FlagOS.flush();
       if (Flag[0] == GV->getDataLayout().getGlobalPrefix())
         OS << Flag.substr(1);
       else
@@ -266,7 +265,6 @@ void llvm::emitLinkerFlagsForGlobalCOFF(raw_ostream &OS, const GlobalValue *GV,
     std::string Flag;
     raw_string_ostream FlagOS(Flag);
     Mangler.getNameWithPrefix(FlagOS, GV, false);
-    FlagOS.flush();
     if (Flag[0] == GV->getDataLayout().getGlobalPrefix())
       OS << Flag.substr(1);
     else

diff --git a/llvm/lib/LTO/LTOCodeGenerator.cpp b/llvm/lib/LTO/LTOCodeGenerator.cpp
@@ -699,7 +699,6 @@ void LTOCodeGenerator::DiagnosticHandler(const DiagnosticInfo &DI) {
   raw_string_ostream Stream(MsgStorage);
   DiagnosticPrinterRawOStream DP(Stream);
   DI.print(DP);
-  Stream.flush();
 
   // If this method has been called it means someone has set up an external
   // diagnostic handler. Assert on that.

diff --git a/llvm/lib/Object/Archive.cpp b/llvm/lib/Object/Archive.cpp
@@ -110,7 +110,6 @@ ArchiveMemberHeader::ArchiveMemberHeader(const Archive *Parent,
       raw_string_ostream OS(Buf);
       OS.write_escaped(
           StringRef(ArMemHdr->Terminator, sizeof(ArMemHdr->Terminator)));
-      OS.flush();
       std::string Msg("terminator characters in archive member \"" + Buf +
                       "\" not the correct \"`\\n\" values for the archive "
                       "member header ");
@@ -281,7 +280,6 @@ Expected<StringRef> ArchiveMemberHeader::getName(uint64_t Size) const {
       std::string Buf;
       raw_string_ostream OS(Buf);
       OS.write_escaped(Name.substr(1).rtrim(' '));
-      OS.flush();
       uint64_t ArchiveOffset =
           reinterpret_cast<const char *>(ArMemHdr) - Parent->getData().data();
       return malformedError("long name offset characters after the '/' are "
@@ -320,7 +318,6 @@ Expected<StringRef> ArchiveMemberHeader::getName(uint64_t Size) const {
       std::string Buf;
       raw_string_ostream OS(Buf);
       OS.write_escaped(Name.substr(3).rtrim(' '));
-      OS.flush();
       uint64_t ArchiveOffset =
           reinterpret_cast<const char *>(ArMemHdr) - Parent->getData().data();
       return malformedError("long name length characters after the #1/ are "

diff --git a/llvm/lib/Object/ArchiveWriter.cpp b/llvm/lib/Object/ArchiveWriter.cpp
@@ -347,7 +347,6 @@ static MemberData computeStringTable(StringRef Names) {
   printWithSpacePadding(Out, "//", 48);
   printWithSpacePadding(Out, Size + Pad, 10);
   Out << "`\n";
-  Out.flush();
   return {{}, std::move(Header), Names, Pad ? "\n" : ""};
 }
 
@@ -959,7 +958,6 @@ computeMemberData(raw_ostream &StringTable, raw_ostream &SymNames,
       printMemberHeader(Out, Pos, StringTable, MemberNames, Kind, Thin, *M,
                         ModTime, Size);
     }
-    Out.flush();
 
     std::vector<unsigned> Symbols;
     if (NeedSymbols != SymtabWritingMode::NoSymtab) {

diff --git a/llvm/lib/Object/IRSymtab.cpp b/llvm/lib/Object/IRSymtab.cpp
@@ -317,7 +317,6 @@ Error Builder::addSymbol(const ModuleSymbolTable &Msymtab,
       std::string FallbackName;
       raw_string_ostream OS(FallbackName);
       Msymtab.printSymbolName(OS, Fallback);
-      OS.flush();
       setStr(Uncommon().COFFWeakExternFallbackName, Saver.save(FallbackName));
     }
   }
@@ -341,7 +340,6 @@ Error Builder::build(ArrayRef<Module *> IRMods) {
     if (Error Err = addModule(M))
       return Err;
 
-  COFFLinkerOptsOS.flush();
   setStr(Hdr.COFFLinkerOpts, Saver.save(COFFLinkerOpts));
 
   // We are about to fill in the header's range fields, so reserve space for it

diff --git a/llvm/lib/ObjectYAML/DWARFEmitter.cpp b/llvm/lib/ObjectYAML/DWARFEmitter.cpp
@@ -1257,7 +1257,6 @@ emitDebugSectionImpl(const DWARFYAML::Data &DI, StringRef Sec,
 
   if (Error Err = EmitFunc(DebugInfoStream, DI))
     return Err;
-  DebugInfoStream.flush();
   if (!Data.empty())
     OutputBuffers[Sec] = MemoryBuffer::getMemBufferCopy(Data);
 

diff --git a/llvm/lib/ObjectYAML/WasmEmitter.cpp b/llvm/lib/ObjectYAML/WasmEmitter.cpp
@@ -77,7 +77,6 @@ class SubSectionWriter {
   SubSectionWriter(raw_ostream &OS) : OS(OS), StringStream(OutString) {}
 
   void done() {
-    StringStream.flush();
     encodeULEB128(OutString.size(), OS);
     OS << OutString;
     OutString.clear();
@@ -545,7 +544,6 @@ void WasmWriter::writeSectionContent(raw_ostream &OS,
     Func.Body.writeAsBinary(StringStream);
 
     // Write the section size followed by the content
-    StringStream.flush();
     encodeULEB128(OutString.size(), OS);
     OS << OutString;
   }
@@ -653,8 +651,6 @@ bool WasmWriter::writeWasm(raw_ostream &OS) {
     if (HasError)
       return false;
 
-    StringStream.flush();
-
     unsigned HeaderSecSizeEncodingLen =
         Sec->HeaderSecSizeEncodingLen.value_or(5);
     unsigned RequiredLen = getULEB128Size(OutString.size());
@@ -682,7 +678,6 @@ bool WasmWriter::writeWasm(raw_ostream &OS) {
     std::string OutString;
     raw_string_ostream StringStream(OutString);
     writeRelocSection(StringStream, *Sec, SectionIndex++);
-    StringStream.flush();
 
     encodeULEB128(OutString.size(), OS);
     OS << OutString;

diff --git a/llvm/lib/Remarks/YAMLRemarkParser.cpp b/llvm/lib/Remarks/YAMLRemarkParser.cpp
@@ -31,7 +31,6 @@ static void handleDiagnostic(const SMDiagnostic &Diag, void *Ctx) {
   Diag.print(/*ProgName=*/nullptr, OS, /*ShowColors*/ false,
              /*ShowKindLabels*/ true);
   OS << '\n';
-  OS.flush();
 }
 
 YAMLParseError::YAMLParseError(StringRef Msg, SourceMgr &SM,

diff --git a/llvm/lib/Support/Chrono.cpp b/llvm/lib/Support/Chrono.cpp
@@ -101,7 +101,6 @@ static void format(const T &Fractional, struct tm &LT, raw_ostream &OS,
       }
     FStream << Style[I];
   }
-  FStream.flush();
   char Buffer[256];  // Should be enough for anywhen.
   size_t Len = strftime(Buffer, sizeof(Buffer), Format.c_str(), &LT);
   OS << (Len ? Buffer : "BAD-DATE-FORMAT");

diff --git a/llvm/tools/lli/lli.cpp b/llvm/tools/lli/lli.cpp
@@ -572,7 +572,6 @@ int main(int argc, char **argv, char * const *envp) {
       std::string Buf;
       raw_string_ostream OS(Buf);
       logAllUnhandledErrors(ArOrErr.takeError(), OS);
-      OS.flush();
       errs() << Buf;
       exit(1);
     }

diff --git a/llvm/tools/llvm-cov/TestingSupport.cpp b/llvm/tools/llvm-cov/TestingSupport.cpp
@@ -38,7 +38,6 @@ int convertForTestingMain(int argc, const char *argv[]) {
     std::string Buf;
     raw_string_ostream OS(Buf);
     logAllUnhandledErrors(ObjErr.takeError(), OS);
-    OS.flush();
     errs() << "error: " << Buf;
     return 1;
   }

diff --git a/llvm/tools/llvm-cxxdump/llvm-cxxdump.cpp b/llvm/tools/llvm-cxxdump/llvm-cxxdump.cpp
@@ -507,7 +507,6 @@ static void dumpArchive(const Archive *Arc) {
         std::string Buf;
         raw_string_ostream OS(Buf);
         logAllUnhandledErrors(std::move(E), OS);
-        OS.flush();
         reportError(Arc->getFileName(), Buf);
       }
       consumeError(ChildOrErr.takeError());

diff --git a/llvm/tools/llvm-exegesis/lib/BenchmarkResult.cpp b/llvm/tools/llvm-exegesis/lib/BenchmarkResult.cpp
@@ -297,7 +297,6 @@ template <> struct MappingContextTraits<exegesis::Benchmark, YamlContext> {
       std::string Str;
       raw_string_ostream OSS(Str);
       Binary.writeAsBinary(OSS);
-      OSS.flush();
       Data.assign(Str.begin(), Str.end());
       return Data;
     }

diff --git a/llvm/tools/llvm-ifs/llvm-ifs.cpp b/llvm/tools/llvm-ifs/llvm-ifs.cpp
@@ -260,7 +260,6 @@ static Error writeIFS(StringRef FilePath, IFSStub &Stub, bool WriteIfChanged) {
   Error YAMLErr = writeIFSToOutputStream(OutStr, Stub);
   if (YAMLErr)
     return YAMLErr;
-  OutStr.flush();
 
   if (WriteIfChanged) {
     if (ErrorOr<std::unique_ptr<MemoryBuffer>> BufOrError =

diff --git a/llvm/tools/llvm-ir2vec/llvm-ir2vec.cpp b/llvm/tools/llvm-ir2vec/llvm-ir2vec.cpp
@@ -143,8 +143,6 @@ class IR2VecTool {
       MaxRelation = std::max(MaxRelation, FuncMaxRelation);
     }
 
-    RelOS.flush();
-
     // Write metadata header followed by relationships
     OS << "MAX_RELATION=" << MaxRelation << '\n';
     OS << Relationships;

diff --git a/llvm/tools/llvm-libtool-darwin/llvm-libtool-darwin.cpp b/llvm/tools/llvm-libtool-darwin/llvm-libtool-darwin.cpp
@@ -572,7 +572,6 @@ checkForDuplicates(const MembersPerArchitectureMap &MembersPerArch) {
       }
     }
 
-    ErrorStream.flush();
     if (ErrorData.size() > 0)
       return createStringError(std::errc::invalid_argument, ErrorData.c_str());
   }
-Original file line number
+Diff line change
@@ Expand Up @@
           }
         }
-        ErrorStream.flush();
         if (ErrorData.size() > 0)
           return createStringError(std::errc::invalid_argument, ErrorData.c_str());
       }
@@ Expand Down @@