[Lldb-commits] [lldb] [lldb] Add generic string view summary provider (PR #171854)

Sergei Druzhkov via lldb-commits lldb-commits at lists.llvm.org
Thu Dec 11 09:26:40 PST 2025


https://github.com/DrSergei updated https://github.com/llvm/llvm-project/pull/171854

>From ef8a0e118f394df64e14d4f399ce1246d5ab53f7 Mon Sep 17 00:00:00 2001
From: Druzhkov Sergei <serzhdruzhok at gmail.com>
Date: Thu, 11 Dec 2025 18:19:30 +0300
Subject: [PATCH 1/3] [lldb] Add generic string view summary provider

---
 .../Plugins/Language/CPlusPlus/CMakeLists.txt |   1 +
 .../Language/CPlusPlus/CPlusPlusLanguage.cpp  |  95 +++++++------
 .../Plugins/Language/CPlusPlus/Generic.h      |   8 ++
 .../Language/CPlusPlus/GenericStringView.cpp  | 131 ++++++++++++++++++
 .../Plugins/Language/CPlusPlus/LibCxx.cpp     |  96 +------------
 .../Plugins/Language/CPlusPlus/LibCxx.h       |  16 ---
 .../Plugins/Language/CPlusPlus/MsvcStl.cpp    |  63 ---------
 .../Plugins/Language/CPlusPlus/MsvcStl.h      |   9 --
 .../TestDataFormatterStdStringView.py         |   5 +
 .../TestDataFormatterStdU8StringView.py       |   2 -
 10 files changed, 196 insertions(+), 230 deletions(-)
 create mode 100644 lldb/source/Plugins/Language/CPlusPlus/GenericStringView.cpp

diff --git a/lldb/source/Plugins/Language/CPlusPlus/CMakeLists.txt b/lldb/source/Plugins/Language/CPlusPlus/CMakeLists.txt
index c52d3bdb31284..940737068fd47 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CMakeLists.txt
+++ b/lldb/source/Plugins/Language/CPlusPlus/CMakeLists.txt
@@ -17,6 +17,7 @@ add_lldb_library(lldbPluginCPlusPlusLanguage PLUGIN
   GenericInitializerList.cpp
   GenericList.cpp
   GenericOptional.cpp
+  GenericStringView.cpp
   LibCxx.cpp
   LibCxxAtomic.cpp
   LibCxxMap.cpp
diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
index ae6086ff89d71..bd58abca7ab04 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
@@ -54,6 +54,8 @@ using namespace lldb;
 using namespace lldb_private;
 using namespace lldb_private::formatters;
 
+using StringElementType = StringPrinter::StringElementType;
+
 LLDB_PLUGIN_DEFINE(CPlusPlusLanguage)
 
 void CPlusPlusLanguage::Initialize() {
@@ -799,42 +801,47 @@ static void LoadLibCxxFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
                 stl_summary_flags, true);
 
   AddCXXSummary(cpp_category_sp,
-                lldb_private::formatters::LibcxxStringViewSummaryProviderASCII,
+                GenericStringViewSummaryProvider<StringElementType::ASCII>,
                 "std::string_view summary provider",
                 "^std::__[[:alnum:]]+::string_view$", stl_summary_flags, true);
   AddCXXSummary(cpp_category_sp,
-                lldb_private::formatters::LibcxxStringViewSummaryProviderASCII,
+                GenericStringViewSummaryProvider<StringElementType::ASCII>,
                 "std::string_view summary provider",
                 "^std::__[[:alnum:]]+::basic_string_view<char, "
                 "std::__[[:alnum:]]+::char_traits<char> >$",
                 stl_summary_flags, true);
   AddCXXSummary(cpp_category_sp,
-                lldb_private::formatters::LibcxxStringViewSummaryProviderASCII,
+                GenericStringViewSummaryProvider<StringElementType::ASCII>,
                 "std::string_view summary provider",
                 "^std::__[[:alnum:]]+::basic_string_view<unsigned char, "
                 "std::__[[:alnum:]]+::char_traits<unsigned char> >$",
                 stl_summary_flags, true);
 
   AddCXXSummary(cpp_category_sp,
-                lldb_private::formatters::LibcxxStringViewSummaryProviderUTF16,
+                GenericStringViewSummaryProvider<StringElementType::UTF8>,
+                "std::u8string_view summary provider",
+                "^std::__[[:alnum:]]+::basic_string_view<char8_t, "
+                "std::__[[:alnum:]]+::char_traits<char8_t> >$",
+                stl_summary_flags, true);
+
+  AddCXXSummary(cpp_category_sp,
+                GenericStringViewSummaryProvider<StringElementType::UTF16>,
                 "std::u16string_view summary provider",
                 "^std::__[[:alnum:]]+::basic_string_view<char16_t, "
                 "std::__[[:alnum:]]+::char_traits<char16_t> >$",
                 stl_summary_flags, true);
 
   AddCXXSummary(cpp_category_sp,
-                lldb_private::formatters::LibcxxStringViewSummaryProviderUTF32,
+                GenericStringViewSummaryProvider<StringElementType::UTF32>,
                 "std::u32string_view summary provider",
                 "^std::__[[:alnum:]]+::basic_string_view<char32_t, "
                 "std::__[[:alnum:]]+::char_traits<char32_t> >$",
                 stl_summary_flags, true);
 
-  AddCXXSummary(cpp_category_sp,
-                lldb_private::formatters::LibcxxWStringViewSummaryProvider,
+  AddCXXSummary(cpp_category_sp, GenericWStringViewSummaryProvider,
                 "std::wstring_view summary provider",
                 "^std::__[[:alnum:]]+::wstring_view$", stl_summary_flags, true);
-  AddCXXSummary(cpp_category_sp,
-                lldb_private::formatters::LibcxxWStringViewSummaryProvider,
+  AddCXXSummary(cpp_category_sp, GenericWStringViewSummaryProvider,
                 "std::wstring_view summary provider",
                 "^std::__[[:alnum:]]+::basic_string_view<wchar_t, "
                 "std::__[[:alnum:]]+::char_traits<wchar_t> >$",
@@ -1696,8 +1703,6 @@ static void LoadCommonStlFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
   stl_synth_flags.SetCascades(true).SetSkipPointers(false).SetSkipReferences(
       false);
 
-  using StringElementType = StringPrinter::StringElementType;
-
   RegisterStdStringSummaryProvider(
       cpp_category_sp, "std::string", "char",
       std::make_shared<CXXFunctionSummaryFormat>(
@@ -1722,9 +1727,39 @@ static void LoadCommonStlFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
           },
           "MSVC STL/libstdc++ std::wstring summary provider"));
 
-  // NOTE: it is loaded as a common formatter because the libc++ version is not
-  // in the `__1` namespace, hence we need to dispatch based on the class
-  // layout.
+  RegisterStdStringViewSummaryProvider(
+      cpp_category_sp, "std::string_view", "char",
+      std::make_shared<CXXFunctionSummaryFormat>(
+          stl_summary_flags,
+          GenericStringViewSummaryProvider<StringElementType::ASCII>,
+          "MSVC STL/libstdc++ std::string_view summary provider"));
+  RegisterStdStringViewSummaryProvider(
+      cpp_category_sp, "std::u8string_view", "char8_t",
+      std::make_shared<CXXFunctionSummaryFormat>(
+          stl_summary_flags,
+          GenericStringViewSummaryProvider<StringElementType::UTF8>,
+          "MSVC STL/libstdc++ std::u8string_view summary provider"));
+  RegisterStdStringViewSummaryProvider(
+      cpp_category_sp, "std::u16string_view", "char16_t",
+      std::make_shared<CXXFunctionSummaryFormat>(
+          stl_summary_flags,
+          GenericStringViewSummaryProvider<StringElementType::UTF16>,
+          "MSVC STL/libstdc++ std::u16string_view summary provider"));
+  RegisterStdStringViewSummaryProvider(
+      cpp_category_sp, "std::u32string_view", "char32_t",
+      std::make_shared<CXXFunctionSummaryFormat>(
+          stl_summary_flags,
+          GenericStringViewSummaryProvider<StringElementType::UTF32>,
+          "MSVC STL/libstdc++ std::u32string_view summary provider"));
+  RegisterStdStringViewSummaryProvider(
+      cpp_category_sp, "std::wstring_view", "wchar_t",
+      std::make_shared<CXXFunctionSummaryFormat>(
+          stl_summary_flags, GenericWStringViewSummaryProvider,
+          "MSVC STL/libstdc++ std::wstring_view summary provider"));
+
+  // NOTE: it is loaded as a common formatter because the libc++ version is
+  // not in the `__1` namespace, hence we need to dispatch based on the
+  // class layout.
   AddCXXSynthetic(cpp_category_sp,
                   GenericInitializerListSyntheticFrontEndCreator,
                   "std::initializer_list synthetic children",
@@ -1837,8 +1872,6 @@ static void LoadMsvcStlFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
   stl_synth_flags.SetCascades(true).SetSkipPointers(false).SetSkipReferences(
       false);
 
-  using StringElementType = StringPrinter::StringElementType;
-
   RegisterStdStringSummaryProvider(
       cpp_category_sp, "std::u8string", "char8_t",
       std::make_shared<CXXFunctionSummaryFormat>(
@@ -1858,36 +1891,6 @@ static void LoadMsvcStlFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
           MsvcStlStringSummaryProvider<StringElementType::UTF32>,
           "MSVC STL std::u32string summary provider"));
 
-  RegisterStdStringViewSummaryProvider(
-      cpp_category_sp, "std::string_view", "char",
-      std::make_shared<CXXFunctionSummaryFormat>(
-          stl_summary_flags,
-          MsvcStlStringViewSummaryProvider<StringElementType::ASCII>,
-          "MSVC STL std::string_view summary provider"));
-  RegisterStdStringViewSummaryProvider(
-      cpp_category_sp, "std::u8string_view", "char8_t",
-      std::make_shared<CXXFunctionSummaryFormat>(
-          stl_summary_flags,
-          MsvcStlStringViewSummaryProvider<StringElementType::UTF8>,
-          "MSVC STL std::u8string_view summary provider"));
-  RegisterStdStringViewSummaryProvider(
-      cpp_category_sp, "std::u16string_view", "char16_t",
-      std::make_shared<CXXFunctionSummaryFormat>(
-          stl_summary_flags,
-          MsvcStlStringViewSummaryProvider<StringElementType::UTF16>,
-          "MSVC STL std::u16string_view summary provider"));
-  RegisterStdStringViewSummaryProvider(
-      cpp_category_sp, "std::u32string_view", "char32_t",
-      std::make_shared<CXXFunctionSummaryFormat>(
-          stl_summary_flags,
-          MsvcStlStringViewSummaryProvider<StringElementType::UTF32>,
-          "MSVC STL std::u32string_view summary provider"));
-  RegisterStdStringViewSummaryProvider(
-      cpp_category_sp, "std::wstring_view", "wchar_t",
-      std::make_shared<CXXFunctionSummaryFormat>(
-          stl_summary_flags, MsvcStlWStringViewSummaryProvider,
-          "MSVC STL std::wstring_view summary provider"));
-
   stl_summary_flags.SetDontShowChildren(false);
 
   AddCXXSynthetic(cpp_category_sp, MsvcStlAtomicSyntheticFrontEndCreator,
diff --git a/lldb/source/Plugins/Language/CPlusPlus/Generic.h b/lldb/source/Plugins/Language/CPlusPlus/Generic.h
index 539eddd3d3e78..9283875852cf1 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/Generic.h
+++ b/lldb/source/Plugins/Language/CPlusPlus/Generic.h
@@ -9,6 +9,7 @@
 #ifndef LLDB_SOURCE_PLUGINS_LANGUAGE_CPLUSPLUS_GENERIC_H
 #define LLDB_SOURCE_PLUGINS_LANGUAGE_CPLUSPLUS_GENERIC_H
 
+#include "lldb/DataFormatters/StringPrinter.h"
 #include "lldb/DataFormatters/TypeSummary.h"
 #include "lldb/Utility/Stream.h"
 #include "lldb/ValueObject/ValueObject.h"
@@ -19,6 +20,13 @@ namespace formatters {
 bool GenericOptionalSummaryProvider(ValueObject &valobj, Stream &stream,
                                     const TypeSummaryOptions &options);
 
+template <StringPrinter::StringElementType element_type>
+bool GenericStringViewSummaryProvider(ValueObject &valobj, Stream &stream,
+                                      const TypeSummaryOptions &options);
+
+bool GenericWStringViewSummaryProvider(ValueObject &valobj, Stream &stream,
+                                       const TypeSummaryOptions &options);
+
 /// Return the ValueObjectSP of the underlying pointer member whose type
 /// is a desugared 'std::shared_ptr::element_type *'.
 lldb::ValueObjectSP GetDesugaredSmartPointerValue(ValueObject &ptr,
diff --git a/lldb/source/Plugins/Language/CPlusPlus/GenericStringView.cpp b/lldb/source/Plugins/Language/CPlusPlus/GenericStringView.cpp
new file mode 100644
index 0000000000000..f566ef210489b
--- /dev/null
+++ b/lldb/source/Plugins/Language/CPlusPlus/GenericStringView.cpp
@@ -0,0 +1,131 @@
+//===-- GenericStringView.cpp --------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===---------------------------------------------------------------------===//
+
+#include "Generic.h"
+#include "LibCxx.h"
+
+#include "lldb/ValueObject/ValueObject.h"
+#include "lldb/lldb-forward.h"
+
+#include "Plugins/Language/CPlusPlus/CxxStringTypes.h"
+#include <tuple>
+
+using namespace lldb;
+using namespace lldb_private;
+using namespace lldb_private::formatters;
+
+using StringElementType = StringPrinter::StringElementType;
+
+enum class StlType {
+  LibCxx,
+  LibStdcpp,
+  MsvcStl,
+};
+
+std::tuple<StlType, lldb::ValueObjectSP, lldb::ValueObjectSP>
+extractStringViewData(ValueObject &valobj) {
+  auto data_sp = valobj.GetChildMemberWithName("_Mydata");
+  if (data_sp)
+    return std::make_tuple(StlType::MsvcStl, data_sp,
+                           valobj.GetChildMemberWithName("_Mysize"));
+  data_sp = valobj.GetChildMemberWithName("_M_str");
+  if (data_sp)
+    return std::make_tuple(StlType::LibStdcpp, data_sp,
+                           valobj.GetChildMemberWithName("_M_len"));
+  return std::make_tuple(
+      StlType::LibCxx,
+      GetChildMemberWithName(valobj,
+                             {ConstString("__data_"), ConstString("__data")}),
+      GetChildMemberWithName(valobj,
+                             {ConstString("__size_"), ConstString("__size")}));
+}
+
+template <StringPrinter::StringElementType element_type>
+static bool formatStringViewImpl(lldb::ValueObjectSP data_sp,
+                                 lldb::ValueObjectSP size_sp, Stream &stream,
+                                 const TypeSummaryOptions &summary_options,
+                                 std::string prefix_token) {
+  if (!data_sp || !size_sp)
+    return false;
+
+  bool success = false;
+  uint64_t size = size_sp->GetValueAsUnsigned(0, &success);
+  if (!success) {
+    stream << "Summary Unavailable";
+    return true;
+  }
+
+  StreamString scratch_stream;
+  success = StringBufferSummaryProvider<element_type>(
+      scratch_stream, summary_options, data_sp, size, prefix_token);
+
+  if (success)
+    stream << scratch_stream.GetData();
+  else
+    stream << "Summary Unavailable";
+  return true;
+}
+
+template <StringElementType element_type>
+static constexpr const char *getPrefixToken() {
+  if constexpr (element_type == StringElementType::ASCII)
+    return "";
+  if constexpr (element_type == StringElementType::UTF8)
+    return "u8";
+  if constexpr (element_type == StringElementType::UTF16)
+    return "u";
+  if constexpr (element_type == StringElementType::UTF32)
+    return "U";
+  llvm_unreachable("invalid element type");
+}
+
+template <StringPrinter::StringElementType element_type>
+bool lldb_private::formatters::GenericStringViewSummaryProvider(
+    ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
+  auto [_, data_sp, size_sp] = extractStringViewData(valobj);
+  return formatStringViewImpl<element_type>(data_sp, size_sp, stream, options,
+                                            getPrefixToken<element_type>());
+}
+
+template bool lldb_private::formatters::GenericStringViewSummaryProvider<
+    StringElementType::ASCII>(ValueObject &, Stream &,
+                              const TypeSummaryOptions &);
+template bool lldb_private::formatters::GenericStringViewSummaryProvider<
+    StringElementType::UTF8>(ValueObject &, Stream &,
+                             const TypeSummaryOptions &);
+template bool lldb_private::formatters::GenericStringViewSummaryProvider<
+    StringElementType::UTF16>(ValueObject &, Stream &,
+                              const TypeSummaryOptions &);
+template bool lldb_private::formatters::GenericStringViewSummaryProvider<
+    StringElementType::UTF32>(ValueObject &, Stream &,
+                              const TypeSummaryOptions &);
+
+bool lldb_private::formatters::GenericWStringViewSummaryProvider(
+    ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
+  auto [stl, data_sp, size_sp] = extractStringViewData(valobj);
+  if (stl == StlType::LibStdcpp)
+    return formatStringViewImpl<StringElementType::UTF32>(data_sp, size_sp,
+                                                          stream, options, "L");
+
+  auto wchar_t_size = GetWCharByteSize(valobj);
+  if (!wchar_t_size)
+    return false;
+
+  switch (*wchar_t_size) {
+  case 1:
+    return formatStringViewImpl<StringElementType::UTF8>(data_sp, size_sp,
+                                                         stream, options, "L");
+  case 2:
+    return formatStringViewImpl<StringElementType::UTF16>(data_sp, size_sp,
+                                                          stream, options, "L");
+  case 4:
+    return formatStringViewImpl<StringElementType::UTF32>(data_sp, size_sp,
+                                                          stream, options, "L");
+  }
+  return false;
+}
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
index 141c5c9a2caf9..a68c9f0fdc963 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
@@ -495,8 +495,8 @@ ExtractLibcxxStringInfo(ValueObject &valobj) {
   StringLayout layout =
       *index_or_err == 0 ? StringLayout::DSC : StringLayout::CSD;
 
-  bool short_mode = false; // this means the string is in short-mode and the
-                           // data is stored inline
+  bool short_mode = false;    // this means the string is in short-mode and the
+                              // data is stored inline
   bool using_bitmasks = true; // Whether the class uses bitmasks for the mode
                               // flag (pre-D123580).
   uint64_t size;
@@ -638,98 +638,6 @@ bool lldb_private::formatters::LibcxxStringSummaryProviderUTF32(
       valobj, stream, summary_options, "U");
 }
 
-static std::tuple<bool, ValueObjectSP, size_t>
-LibcxxExtractStringViewData(ValueObject& valobj) {
-  auto dataobj = GetChildMemberWithName(
-      valobj, {ConstString("__data_"), ConstString("__data")});
-  auto sizeobj = GetChildMemberWithName(
-      valobj, {ConstString("__size_"), ConstString("__size")});
-  if (!dataobj || !sizeobj)
-    return std::make_tuple<bool,ValueObjectSP,size_t>(false, {}, {});
-
-  if (!dataobj->GetError().Success() || !sizeobj->GetError().Success())
-    return std::make_tuple<bool,ValueObjectSP,size_t>(false, {}, {});
-
-  bool success{false};
-  uint64_t size = sizeobj->GetValueAsUnsigned(0, &success);
-  if (!success)
-    return std::make_tuple<bool,ValueObjectSP,size_t>(false, {}, {});
-
-  return std::make_tuple(true,dataobj,size);
-}
-
-template <StringPrinter::StringElementType element_type>
-static bool formatStringViewImpl(ValueObject &valobj, Stream &stream,
-                                 const TypeSummaryOptions &summary_options,
-                                 std::string prefix_token) {
-
-  bool success;
-  ValueObjectSP dataobj;
-  size_t size;
-  std::tie(success, dataobj, size) = LibcxxExtractStringViewData(valobj);
-
-  if (!success) {
-    stream << "Summary Unavailable";
-    return true;
-  }
-
-  return StringBufferSummaryProvider<element_type>(stream, summary_options,
-                                                   dataobj, size, prefix_token);
-}
-
-bool lldb_private::formatters::LibcxxStringViewSummaryProviderASCII(
-    ValueObject &valobj, Stream &stream,
-    const TypeSummaryOptions &summary_options) {
-  return formatStringViewImpl<StringPrinter::StringElementType::ASCII>(
-      valobj, stream, summary_options, "");
-}
-
-bool lldb_private::formatters::LibcxxStringViewSummaryProviderUTF16(
-    ValueObject &valobj, Stream &stream,
-    const TypeSummaryOptions &summary_options) {
-  return formatStringViewImpl<StringPrinter::StringElementType::UTF16>(
-      valobj, stream, summary_options, "u");
-}
-
-bool lldb_private::formatters::LibcxxStringViewSummaryProviderUTF32(
-    ValueObject &valobj, Stream &stream,
-    const TypeSummaryOptions &summary_options) {
-  return formatStringViewImpl<StringPrinter::StringElementType::UTF32>(
-      valobj, stream, summary_options, "U");
-}
-
-bool lldb_private::formatters::LibcxxWStringViewSummaryProvider(
-    ValueObject &valobj, Stream &stream,
-    const TypeSummaryOptions &summary_options) {
-
-  bool success;
-  ValueObjectSP dataobj;
-  size_t size;
-  std::tie(success, dataobj, size) = LibcxxExtractStringViewData(valobj);
-
-  if (!success) {
-    stream << "Summary Unavailable";
-    return true;
-  }
-
-  auto wchar_t_size = GetWCharByteSize(valobj);
-  if (!wchar_t_size)
-    return false;
-
-  switch (*wchar_t_size) {
-  case 1:
-    return StringBufferSummaryProvider<StringPrinter::StringElementType::UTF8>(
-        stream, summary_options, dataobj, size, "L");
-  case 2:
-    return StringBufferSummaryProvider<StringPrinter::StringElementType::UTF16>(
-        stream, summary_options, dataobj, size, "L");
-  case 4:
-    return StringBufferSummaryProvider<StringPrinter::StringElementType::UTF32>(
-        stream, summary_options, dataobj, size, "L");
-  }
-  return false;
-}
-
 static bool
 LibcxxChronoTimePointSecondsSummaryProvider(ValueObject &valobj, Stream &stream,
                                             const TypeSummaryOptions &options,
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.h b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.h
index 8fd29288da35f..d1a30d176fe7a 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.h
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.h
@@ -59,22 +59,6 @@ bool LibcxxWStringSummaryProvider(
     ValueObject &valobj, Stream &stream,
     const TypeSummaryOptions &options); // libc++ std::wstring
 
-bool LibcxxStringViewSummaryProviderASCII(
-    ValueObject &valueObj, Stream &stream,
-    const TypeSummaryOptions &summary_options); // libc++ std::string_view
-
-bool LibcxxStringViewSummaryProviderUTF16(
-    ValueObject &valobj, Stream &stream,
-    const TypeSummaryOptions &summary_options); // libc++ std::u16string_view
-
-bool LibcxxStringViewSummaryProviderUTF32(
-    ValueObject &valobj, Stream &stream,
-    const TypeSummaryOptions &summary_options); // libc++ std::u32string_view
-
-bool LibcxxWStringViewSummaryProvider(
-    ValueObject &valobj, Stream &stream,
-    const TypeSummaryOptions &options); // libc++ std::wstring_view
-
 bool LibcxxStdSliceArraySummaryProvider(
     ValueObject &valobj, Stream &stream,
     const TypeSummaryOptions &options); // libc++ std::slice_array
diff --git a/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.cpp b/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.cpp
index 8fb305b284bbb..5d0f20b1beaae 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.cpp
@@ -112,33 +112,6 @@ static bool formatStringImpl(ValueObject &valobj, Stream &stream,
   return true;
 }
 
-template <StringPrinter::StringElementType element_type>
-static bool formatStringViewImpl(ValueObject &valobj, Stream &stream,
-                                 const TypeSummaryOptions &summary_options,
-                                 std::string prefix_token) {
-  auto data_sp = valobj.GetChildMemberWithName("_Mydata");
-  auto size_sp = valobj.GetChildMemberWithName("_Mysize");
-  if (!data_sp || !size_sp)
-    return false;
-
-  bool success = false;
-  uint64_t size = size_sp->GetValueAsUnsigned(0, &success);
-  if (!success) {
-    stream << "Summary Unavailable";
-    return true;
-  }
-
-  StreamString scratch_stream;
-  success = StringBufferSummaryProvider<element_type>(
-      scratch_stream, summary_options, data_sp, size, prefix_token);
-
-  if (success)
-    stream << scratch_stream.GetData();
-  else
-    stream << "Summary Unavailable";
-  return true;
-}
-
 bool lldb_private::formatters::IsMsvcStlStringType(ValueObject &valobj) {
   std::vector<uint32_t> indexes;
   return valobj.GetCompilerType().GetIndexOfChildMemberWithName("_Mypair", true,
@@ -180,39 +153,3 @@ bool lldb_private::formatters::MsvcStlStringSummaryProvider<
   return MsvcStlStringSummaryProviderImpl<StringElementType::UTF32>(
       valobj, stream, summary_options, "U");
 }
-
-bool lldb_private::formatters::MsvcStlWStringViewSummaryProvider(
-    ValueObject &valobj, Stream &stream,
-    const TypeSummaryOptions &summary_options) {
-  return formatStringViewImpl<StringElementType::UTF16>(valobj, stream,
-                                                        summary_options, "L");
-}
-
-template <>
-bool lldb_private::formatters::MsvcStlStringViewSummaryProvider<
-    StringElementType::ASCII>(ValueObject &valobj, Stream &stream,
-                              const TypeSummaryOptions &summary_options) {
-  return formatStringViewImpl<StringElementType::ASCII>(valobj, stream,
-                                                        summary_options, "");
-}
-template <>
-bool lldb_private::formatters::MsvcStlStringViewSummaryProvider<
-    StringElementType::UTF8>(ValueObject &valobj, Stream &stream,
-                             const TypeSummaryOptions &summary_options) {
-  return formatStringViewImpl<StringElementType::UTF8>(valobj, stream,
-                                                       summary_options, "u8");
-}
-template <>
-bool lldb_private::formatters::MsvcStlStringViewSummaryProvider<
-    StringElementType::UTF16>(ValueObject &valobj, Stream &stream,
-                              const TypeSummaryOptions &summary_options) {
-  return formatStringViewImpl<StringElementType::UTF16>(valobj, stream,
-                                                        summary_options, "u");
-}
-template <>
-bool lldb_private::formatters::MsvcStlStringViewSummaryProvider<
-    StringElementType::UTF32>(ValueObject &valobj, Stream &stream,
-                              const TypeSummaryOptions &summary_options) {
-  return formatStringViewImpl<StringElementType::UTF32>(valobj, stream,
-                                                        summary_options, "U");
-}
diff --git a/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.h b/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.h
index e818b88e202ef..dab809bbe10cf 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.h
+++ b/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.h
@@ -29,15 +29,6 @@ bool MsvcStlWStringSummaryProvider(
     ValueObject &valobj, Stream &stream,
     const TypeSummaryOptions &options); // VC 2015+ std::wstring
 
-template <StringPrinter::StringElementType element_type>
-bool MsvcStlStringViewSummaryProvider(
-    ValueObject &valobj, Stream &stream,
-    const TypeSummaryOptions &summary_options); // std::{u8,u16,u32}?string_view
-
-bool MsvcStlWStringViewSummaryProvider(
-    ValueObject &valobj, Stream &stream,
-    const TypeSummaryOptions &options); // std::wstring_view
-
 // MSVC STL std::shared_ptr<> and std::weak_ptr<>
 bool IsMsvcStlSmartPointer(ValueObject &valobj);
 bool MsvcStlSmartPointerSummaryProvider(ValueObject &valobj, Stream &stream,
diff --git a/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/string_view/TestDataFormatterStdStringView.py b/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/string_view/TestDataFormatterStdStringView.py
index 5c915b6d9f588..8895156abb366 100644
--- a/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/string_view/TestDataFormatterStdStringView.py
+++ b/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/string_view/TestDataFormatterStdStringView.py
@@ -175,6 +175,11 @@ def test_libcxx(self):
         self.build(dictionary={"USE_LIBCPP": 1})
         self.do_test()
 
+    @add_test_categories(["libstdcxx"])
+    def test_libstdcxx(self):
+        self.build(dictionary={"USE_LIBSTDCPP": 1})
+        self.do_test()
+
     @add_test_categories(["msvcstl"])
     def test_msvcstl(self):
         self.build()
diff --git a/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/u8string_view/TestDataFormatterStdU8StringView.py b/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/u8string_view/TestDataFormatterStdU8StringView.py
index 6cf72d18a864f..7d0f3be8a2623 100644
--- a/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/u8string_view/TestDataFormatterStdU8StringView.py
+++ b/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/u8string_view/TestDataFormatterStdU8StringView.py
@@ -34,13 +34,11 @@ def do_test(self):
             ],
         )
 
-    @expectedFailureAll(bugnumber="No libc++ formatters for std::u8string_view yet.")
     @add_test_categories(["libc++"])
     def test_libcxx(self):
         self.build(dictionary={"USE_LIBCPP": 1})
         self.do_test()
 
-    @expectedFailureAll(bugnumber="No libstdc++ formatters for std::u8string_view yet.")
     @add_test_categories(["libstdcxx"])
     def test_libstdcxx(self):
         self.build(dictionary={"USE_LIBSTDCPP": 1})

>From a9db3ec49a1a5d6007adc48e8d06886d9794c3eb Mon Sep 17 00:00:00 2001
From: Druzhkov Sergei <serzhdruzhok at gmail.com>
Date: Thu, 11 Dec 2025 20:14:48 +0300
Subject: [PATCH 2/3] Fix review comments

---
 .../Language/CPlusPlus/GenericStringView.cpp  | 36 +++++++++----------
 .../Plugins/Language/CPlusPlus/LibCxx.cpp     |  9 +++++
 .../Plugins/Language/CPlusPlus/LibCxx.h       |  3 ++
 .../Plugins/Language/CPlusPlus/LibStdcpp.cpp  |  7 +++-
 .../Plugins/Language/CPlusPlus/LibStdcpp.h    |  3 ++
 .../Plugins/Language/CPlusPlus/MsvcStl.cpp    |  6 ++++
 .../Plugins/Language/CPlusPlus/MsvcStl.h      |  3 ++
 7 files changed, 47 insertions(+), 20 deletions(-)

diff --git a/lldb/source/Plugins/Language/CPlusPlus/GenericStringView.cpp b/lldb/source/Plugins/Language/CPlusPlus/GenericStringView.cpp
index f566ef210489b..35b574bc6ef8d 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/GenericStringView.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/GenericStringView.cpp
@@ -8,6 +8,8 @@
 
 #include "Generic.h"
 #include "LibCxx.h"
+#include "LibStdcpp.h"
+#include "MsvcStl.h"
 
 #include "lldb/ValueObject/ValueObject.h"
 #include "lldb/lldb-forward.h"
@@ -29,20 +31,14 @@ enum class StlType {
 
 std::tuple<StlType, lldb::ValueObjectSP, lldb::ValueObjectSP>
 extractStringViewData(ValueObject &valobj) {
-  auto data_sp = valobj.GetChildMemberWithName("_Mydata");
-  if (data_sp)
-    return std::make_tuple(StlType::MsvcStl, data_sp,
-                           valobj.GetChildMemberWithName("_Mysize"));
-  data_sp = valobj.GetChildMemberWithName("_M_str");
-  if (data_sp)
-    return std::make_tuple(StlType::LibStdcpp, data_sp,
-                           valobj.GetChildMemberWithName("_M_len"));
-  return std::make_tuple(
-      StlType::LibCxx,
-      GetChildMemberWithName(valobj,
-                             {ConstString("__data_"), ConstString("__data")}),
-      GetChildMemberWithName(valobj,
-                             {ConstString("__size_"), ConstString("__size")}));
+  auto [data_sp, size_sp] = MsvcStlExtractStringViewData(valobj);
+  if (data_sp && size_sp)
+    return std::make_tuple(StlType::MsvcStl, data_sp, size_sp);
+  std::tie(data_sp, size_sp) = LibcxxExtractStringViewData(valobj);
+  if (data_sp && size_sp)
+    return std::make_tuple(StlType::LibCxx, data_sp, size_sp);
+  std::tie(data_sp, size_sp) = LibStdcppExtractStringViewData(valobj);
+  return std::make_tuple(StlType::LibStdcpp, data_sp, size_sp);
 }
 
 template <StringPrinter::StringElementType element_type>
@@ -73,14 +69,16 @@ static bool formatStringViewImpl(lldb::ValueObjectSP data_sp,
 
 template <StringElementType element_type>
 static constexpr const char *getPrefixToken() {
-  if constexpr (element_type == StringElementType::ASCII)
+  switch (element_type) {
+  case StringElementType::ASCII:
     return "";
-  if constexpr (element_type == StringElementType::UTF8)
+  case StringElementType::UTF8:
     return "u8";
-  if constexpr (element_type == StringElementType::UTF16)
+  case StringElementType::UTF16:
     return "u";
-  if constexpr (element_type == StringElementType::UTF32)
+  case StringElementType::UTF32:
     return "U";
+  }
   llvm_unreachable("invalid element type");
 }
 
@@ -108,7 +106,7 @@ template bool lldb_private::formatters::GenericStringViewSummaryProvider<
 bool lldb_private::formatters::GenericWStringViewSummaryProvider(
     ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
   auto [stl, data_sp, size_sp] = extractStringViewData(valobj);
-  if (stl == StlType::LibStdcpp)
+  if (stl == StlType::MsvcStl)
     return formatStringViewImpl<StringElementType::UTF32>(data_sp, size_sp,
                                                           stream, options, "L");
 
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
index a68c9f0fdc963..96de5dbc9ac6b 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
@@ -638,6 +638,15 @@ bool lldb_private::formatters::LibcxxStringSummaryProviderUTF32(
       valobj, stream, summary_options, "U");
 }
 
+std::tuple<lldb::ValueObjectSP, lldb::ValueObjectSP>
+lldb_private::formatters::LibcxxExtractStringViewData(ValueObject &valobj) {
+  return std::make_tuple(
+      GetChildMemberWithName(valobj,
+                             {ConstString("__data_"), ConstString("__data")}),
+      GetChildMemberWithName(valobj,
+                             {ConstString("__size_"), ConstString("__size")}));
+}
+
 static bool
 LibcxxChronoTimePointSecondsSummaryProvider(ValueObject &valobj, Stream &stream,
                                             const TypeSummaryOptions &options,
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.h b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.h
index d1a30d176fe7a..1287e9af188c6 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.h
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.h
@@ -59,6 +59,9 @@ bool LibcxxWStringSummaryProvider(
     ValueObject &valobj, Stream &stream,
     const TypeSummaryOptions &options); // libc++ std::wstring
 
+std::tuple<lldb::ValueObjectSP, lldb::ValueObjectSP>
+LibcxxExtractStringViewData(ValueObject &valobj);
+
 bool LibcxxStdSliceArraySummaryProvider(
     ValueObject &valobj, Stream &stream,
     const TypeSummaryOptions &options); // libc++ std::slice_array
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibStdcpp.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibStdcpp.cpp
index 86f0a5ad78a9a..5da4da92ed075 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibStdcpp.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibStdcpp.cpp
@@ -73,7 +73,6 @@ class LibStdcppSharedPtrSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
   llvm::Expected<size_t> GetIndexOfChildWithName(ConstString name) override;
 
 private:
-
   // The lifetime of a ValueObject and all its derivative ValueObjects
   // (children, clones, etc.) is managed by a ClusterManager. These
   // objects are only destroyed when every shared pointer to any of them
@@ -246,6 +245,12 @@ bool lldb_private::formatters::LibStdcppStringSummaryProvider(
   return true;
 }
 
+std::tuple<lldb::ValueObjectSP, lldb::ValueObjectSP>
+lldb_private::formatters::LibStdcppExtractStringViewData(ValueObject &valobj) {
+  return std::make_tuple(valobj.GetChildMemberWithName("_M_str"),
+                         valobj.GetChildMemberWithName("_M_len"));
+}
+
 LibStdcppSharedPtrSyntheticFrontEnd::LibStdcppSharedPtrSyntheticFrontEnd(
     lldb::ValueObjectSP valobj_sp)
     : SyntheticChildrenFrontEnd(*valobj_sp) {
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibStdcpp.h b/lldb/source/Plugins/Language/CPlusPlus/LibStdcpp.h
index 8d2c81f2bbcbb..741d69959f24e 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibStdcpp.h
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibStdcpp.h
@@ -20,6 +20,9 @@ bool LibStdcppStringSummaryProvider(
     ValueObject &valobj, Stream &stream,
     const TypeSummaryOptions &options); // libstdc++ std::string
 
+std::tuple<lldb::ValueObjectSP, lldb::ValueObjectSP>
+LibStdcppExtractStringViewData(ValueObject &valobj);
+
 bool LibStdcppSmartPointerSummaryProvider(
     ValueObject &valobj, Stream &stream,
     const TypeSummaryOptions
diff --git a/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.cpp b/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.cpp
index 5d0f20b1beaae..a830cf373cca5 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.cpp
@@ -153,3 +153,9 @@ bool lldb_private::formatters::MsvcStlStringSummaryProvider<
   return MsvcStlStringSummaryProviderImpl<StringElementType::UTF32>(
       valobj, stream, summary_options, "U");
 }
+
+std::tuple<lldb::ValueObjectSP, lldb::ValueObjectSP>
+lldb_private::formatters::MsvcStlExtractStringViewData(ValueObject &valobj) {
+  return std::make_tuple(valobj.GetChildMemberWithName("_Mydata"),
+                         valobj.GetChildMemberWithName("_Mysize"));
+}
diff --git a/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.h b/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.h
index dab809bbe10cf..89b1867b7a38f 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.h
+++ b/lldb/source/Plugins/Language/CPlusPlus/MsvcStl.h
@@ -29,6 +29,9 @@ bool MsvcStlWStringSummaryProvider(
     ValueObject &valobj, Stream &stream,
     const TypeSummaryOptions &options); // VC 2015+ std::wstring
 
+std::tuple<lldb::ValueObjectSP, lldb::ValueObjectSP>
+MsvcStlExtractStringViewData(ValueObject &valobj);
+
 // MSVC STL std::shared_ptr<> and std::weak_ptr<>
 bool IsMsvcStlSmartPointer(ValueObject &valobj);
 bool MsvcStlSmartPointerSummaryProvider(ValueObject &valobj, Stream &stream,

>From 824bcee1fb5fa443c72fe8ec105576c3b4e017ec Mon Sep 17 00:00:00 2001
From: Druzhkov Sergei <serzhdruzhok at gmail.com>
Date: Thu, 11 Dec 2025 20:25:36 +0300
Subject: [PATCH 3/3] Unify logic

---
 .../Language/CPlusPlus/GenericStringView.cpp  | 21 ++++++-------------
 1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/lldb/source/Plugins/Language/CPlusPlus/GenericStringView.cpp b/lldb/source/Plugins/Language/CPlusPlus/GenericStringView.cpp
index 35b574bc6ef8d..532394e038a47 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/GenericStringView.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/GenericStringView.cpp
@@ -23,22 +23,16 @@ using namespace lldb_private::formatters;
 
 using StringElementType = StringPrinter::StringElementType;
 
-enum class StlType {
-  LibCxx,
-  LibStdcpp,
-  MsvcStl,
-};
-
-std::tuple<StlType, lldb::ValueObjectSP, lldb::ValueObjectSP>
+std::tuple<lldb::ValueObjectSP, lldb::ValueObjectSP>
 extractStringViewData(ValueObject &valobj) {
   auto [data_sp, size_sp] = MsvcStlExtractStringViewData(valobj);
   if (data_sp && size_sp)
-    return std::make_tuple(StlType::MsvcStl, data_sp, size_sp);
+    return std::make_tuple(data_sp, size_sp);
   std::tie(data_sp, size_sp) = LibcxxExtractStringViewData(valobj);
   if (data_sp && size_sp)
-    return std::make_tuple(StlType::LibCxx, data_sp, size_sp);
+    return std::make_tuple(data_sp, size_sp);
   std::tie(data_sp, size_sp) = LibStdcppExtractStringViewData(valobj);
-  return std::make_tuple(StlType::LibStdcpp, data_sp, size_sp);
+  return std::make_tuple(data_sp, size_sp);
 }
 
 template <StringPrinter::StringElementType element_type>
@@ -85,7 +79,7 @@ static constexpr const char *getPrefixToken() {
 template <StringPrinter::StringElementType element_type>
 bool lldb_private::formatters::GenericStringViewSummaryProvider(
     ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
-  auto [_, data_sp, size_sp] = extractStringViewData(valobj);
+  auto [data_sp, size_sp] = extractStringViewData(valobj);
   return formatStringViewImpl<element_type>(data_sp, size_sp, stream, options,
                                             getPrefixToken<element_type>());
 }
@@ -105,10 +99,7 @@ template bool lldb_private::formatters::GenericStringViewSummaryProvider<
 
 bool lldb_private::formatters::GenericWStringViewSummaryProvider(
     ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
-  auto [stl, data_sp, size_sp] = extractStringViewData(valobj);
-  if (stl == StlType::MsvcStl)
-    return formatStringViewImpl<StringElementType::UTF32>(data_sp, size_sp,
-                                                          stream, options, "L");
+  auto [data_sp, size_sp] = extractStringViewData(valobj);
 
   auto wchar_t_size = GetWCharByteSize(valobj);
   if (!wchar_t_size)



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