PR51018: Remove explicit conversions from SmallString to StringRef to future-proof against C++23

C++23 will make these conversions ambiguous - so fix them to make the
codebase forward-compatible with C++23 (& a follow-up change I've made
will make this ambiguous/invalid even in <C++23 so we don't regress
this & it generally improves the code anyway)

lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -1684,7 +1684,7 @@ void AsmPrinter::emitRemarksSection(remarks::RemarkStreamer &RS) {
   std::string Buf;
   raw_string_ostream OS(Buf);
   std::unique_ptr<remarks::MetaSerializer> MetaSerializer =
-      Filename ? RemarkSerializer.metaSerializer(OS, StringRef(*Filename))
+      Filename ? RemarkSerializer.metaSerializer(OS, Filename->str())
                : RemarkSerializer.metaSerializer(OS);
   MetaSerializer->emit();
 

lib/IR/ValueSymbolTable.cpp

@@ -61,7 +61,7 @@ ValueName *ValueSymbolTable::makeUniqueName(Value *V,
     S << ++LastUnique;
 
     // Try insert the vmap entry with this suffix.
-    auto IterBool = vmap.insert(std::make_pair(UniqueName, V));
+    auto IterBool = vmap.insert(std::make_pair(UniqueName.str(), V));
     if (IterBool.second)
       return &*IterBool.first;
   }

lib/LTO/LTOModule.cpp

@@ -545,7 +545,8 @@ void LTOModule::addPotentialUndefinedSymbol(ModuleSymbolTable::Symbol Sym,
     name.c_str();
   }
 
-  auto IterBool = _undefines.insert(std::make_pair(name, NameAndAttributes()));
+  auto IterBool =
+      _undefines.insert(std::make_pair(name.str(), NameAndAttributes()));
 
   // we already have the symbol
   if (!IterBool.second)
@@ -582,7 +583,7 @@ void LTOModule::parseSymbols() {
         SymTab.printSymbolName(OS, Sym);
         Buffer.c_str();
       }
-      StringRef Name(Buffer);
+      StringRef Name = Buffer;
 
       if (IsUndefined)
         addAsmGlobalSymbolUndef(Name);

lib/MC/MCContext.cpp

@@ -261,7 +261,7 @@ MCSymbol *MCContext::createSymbol(StringRef Name, bool AlwaysAddSuffix,
       NewName.resize(Name.size());
       raw_svector_ostream(NewName) << NextUniqueID++;
     }
-    auto NameEntry = UsedNames.insert(std::make_pair(NewName, true));
+    auto NameEntry = UsedNames.insert(std::make_pair(NewName.str(), true));
     if (NameEntry.second || !NameEntry.first->second) {
       // Ok, we found a name.
       // Mark it as used for a non-section symbol.
@@ -394,7 +394,7 @@ MCContext::createXCOFFSymbolImpl(const StringMapEntry<bool> *Name,
   else
     ValidName.append(InvalidName);
 
-  auto NameEntry = UsedNames.insert(std::make_pair(ValidName, true));
+  auto NameEntry = UsedNames.insert(std::make_pair(ValidName.str(), true));
   assert((NameEntry.second || !NameEntry.first->second) &&
          "This name is used somewhere else.");
   // Mark the name as used for a non-section symbol.

lib/Object/IRSymtab.cpp

@@ -230,7 +230,7 @@ Error Builder::addSymbol(const ModuleSymbolTable &Msymtab,
     raw_svector_ostream OS(Name);
     Msymtab.printSymbolName(OS, Msym);
   }
-  setStr(Sym.Name, Saver.save(StringRef(Name)));
+  setStr(Sym.Name, Saver.save(Name.str()));
 
   auto Flags = Msymtab.getSymbolFlags(Msym);
   if (Flags & object::BasicSymbolRef::SF_Undefined)

lib/ProfileData/Coverage/CoverageMappingWriter.cpp

@@ -63,7 +63,7 @@ void CoverageFilenamesSectionWriter::write(raw_ostream &OS, bool Compress) {
   encodeULEB128(Filenames.size(), OS);
   encodeULEB128(FilenamesStr.size(), OS);
   encodeULEB128(doCompression ? CompressedStr.size() : 0U, OS);
-  OS << (doCompression ? StringRef(CompressedStr) : StringRef(FilenamesStr));
+  OS << (doCompression ? CompressedStr.str() : StringRef(FilenamesStr));
 }
 
 namespace {

lib/Support/CommandLine.cpp

@@ -864,7 +864,7 @@ void cl::TokenizeGNUCommandLine(StringRef Src, StringSaver &Saver,
     // End the token if this is whitespace.
     if (isWhitespace(C)) {
       if (!Token.empty())
-        NewArgv.push_back(Saver.save(StringRef(Token)).data());
+        NewArgv.push_back(Saver.save(Token.str()).data());
       // Mark the end of lines in response files.
       if (MarkEOLs && C == '\n')
         NewArgv.push_back(nullptr);
@@ -878,7 +878,7 @@ void cl::TokenizeGNUCommandLine(StringRef Src, StringSaver &Saver,
 
   // Append the last token after hitting EOF with no whitespace.
   if (!Token.empty())
-    NewArgv.push_back(Saver.save(StringRef(Token)).data());
+    NewArgv.push_back(Saver.save(Token.str()).data());
 }
 
 /// Backslashes are interpreted in a rather complicated way in the Windows-style

lib/Support/Signals.cpp

@@ -165,8 +165,8 @@ static bool printSymbolizedStackTrace(StringRef Argv0, void **StackTrace,
     }
   }
 
-  Optional<StringRef> Redirects[] = {StringRef(InputFile),
+  Optional<StringRef> Redirects[] = {InputFile.str(), OutputFile.str(),
-                                     StringRef(OutputFile), StringRef("")};
+                                     StringRef("")};
   StringRef Args[] = {"llvm-symbolizer", "--functions=linkage", "--inlining",
 #ifdef _WIN32
                       // Pass --relative-address on Windows so that we don't

lib/Support/VirtualFileSystem.cpp

@@ -1604,7 +1604,7 @@ private:
     }
 
     // Remove trailing slash(es), being careful not to remove the root path
-    StringRef Trimmed(Name);
+    StringRef Trimmed = Name;
     size_t RootPathLen = sys::path::root_path(Trimmed, path_style).size();
     while (Trimmed.size() > RootPathLen &&
            sys::path::is_separator(Trimmed.back(), path_style))

lib/Transforms/Scalar/MergeICmps.cpp

@@ -596,7 +596,7 @@ private:
         append(BB->getName());
       }
     }
-    return StringRef(Scratch);
+    return Scratch.str();
   }
 };
 } // namespace

lib/Transforms/Utils/MemoryOpRemark.cpp

@@ -217,7 +217,7 @@ void MemoryOpRemark::visitIntrinsicCall(const IntrinsicInst &II) {
   }
 
   auto R = makeRemark(RemarkPass.data(), remarkName(RK_IntrinsicCall), &II);
-  visitCallee(StringRef(CallTo), /*KnownLibCall=*/true, *R);
+  visitCallee(CallTo.str(), /*KnownLibCall=*/true, *R);
   visitSizeOperand(II.getOperand(2), *R);
 
   auto *CIVolatile = dyn_cast<ConstantInt>(II.getOperand(3));

tools/llvm-exegesis/lib/Analysis.cpp

@@ -116,7 +116,7 @@ void Analysis::writeSnippet(raw_ostream &OS, ArrayRef<uint8_t> Bytes,
     raw_svector_ostream OSS(InstPrinterStr);
     InstPrinter_->printInst(&MI, 0, "", *SubtargetInfo_, OSS);
     Bytes = Bytes.drop_front(MISize);
-    Lines.emplace_back(StringRef(InstPrinterStr).trim());
+    Lines.emplace_back(InstPrinterStr.str().trim());
   }
   writeEscaped<Tag>(OS, join(Lines, Separator));
 }

tools/llvm-readobj/COFFDumper.cpp

@@ -1874,7 +1874,7 @@ void COFFDumper::printResourceDirectoryTable(
         OS << ": (ID " << Entry.Identifier.ID << ")";
       }
     }
-    Name = StringRef(IDStr);
+    Name = IDStr;
     ListScope ResourceType(W, Level.str() + Name.str());
     if (Entry.Offset.isSubDir()) {
       W.printHex("Table Offset", Entry.Offset.value());

unittests/Bitstream/BitstreamWriterTest.cpp

@@ -38,7 +38,7 @@ TEST(BitstreamWriterTest, emitBlobWithSize) {
     W.Emit('r', 8);
     W.Emit(0, 8);
   }
-  EXPECT_EQ(StringRef(Expected), Buffer);
+  EXPECT_EQ(Expected.str(), Buffer);
 }
 
 TEST(BitstreamWriterTest, emitBlobEmpty) {

unittests/DebugInfo/DWARF/DWARFDieManualExtractTest.cpp

@@ -72,7 +72,7 @@ TEST(DWARFDie, manualExtractDump) {
       "0x0000000b: DW_TAG_compile_unit",
       "              DW_AT_name	(\"/tmp/main.c\")",
       "              DW_AT_language	(DW_LANG_C)"};
-  StringRef(Output).split(Strings, '\n', -1, false);
+  Output.str().split(Strings, '\n', -1, false);
   ASSERT_EQ(Strings.size(), NumOfLines);
   for (size_t I = 0; I < NumOfLines; ++I)
     EXPECT_EQ(ValidStrings[I], Strings[I]);

unittests/Support/CommandLineTest.cpp

@@ -1064,7 +1064,7 @@ TEST(CommandLineTest, ReadConfigFile) {
   llvm::SmallString<128> CurrDir;
   std::error_code EC = llvm::sys::fs::current_path(CurrDir);
   EXPECT_TRUE(!EC);
-  EXPECT_TRUE(StringRef(CurrDir) != TestDir.path());
+  EXPECT_NE(CurrDir.str(), TestDir.path());
 
   llvm::BumpPtrAllocator A;
   llvm::StringSaver Saver(A);

unittests/Support/LockFileManagerTest.cpp

@@ -36,7 +36,7 @@ TEST(LockFileManagerTest, Basic) {
   }
 
   // Now that the lock is out of scope, the file should be gone.
-  EXPECT_FALSE(sys::fs::exists(StringRef(LockedFile)));
+  EXPECT_FALSE(sys::fs::exists(LockedFile.str()));
 }
 
 TEST(LockFileManagerTest, LinkLockExists) {
@@ -52,7 +52,7 @@ TEST(LockFileManagerTest, LinkLockExists) {
   sys::path::append(TmpFileLock, "file.lock-000");
 
   int FD;
-  std::error_code EC = sys::fs::openFileForWrite(StringRef(TmpFileLock), FD);
+  std::error_code EC = sys::fs::openFileForWrite(TmpFileLock.str(), FD);
   ASSERT_FALSE(EC);
 
   int Ret = close(FD);
@@ -61,7 +61,7 @@ TEST(LockFileManagerTest, LinkLockExists) {
   EC = sys::fs::create_link(TmpFileLock.str(), FileLocK.str());
   ASSERT_FALSE(EC);
 
-  EC = sys::fs::remove(StringRef(TmpFileLock));
+  EC = sys::fs::remove(TmpFileLock.str());
   ASSERT_FALSE(EC);
 
   {
@@ -72,7 +72,7 @@ TEST(LockFileManagerTest, LinkLockExists) {
   }
 
   // Now that the lock is out of scope, the file should be gone.
-  EXPECT_FALSE(sys::fs::exists(StringRef(LockedFile)));
+  EXPECT_FALSE(sys::fs::exists(LockedFile.str()));
 }