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

via lldb-commits lldb-commits at lists.llvm.org
Thu Dec 11 08:57:46 PST 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: Sergei Druzhkov (DrSergei)

<details>
<summary>Changes</summary>

This patch introduces general summary provider for `std::string_view` and simial types. I tried to remove copy-paste between different stl implementations. I cannot check now how it works on Windows machine, but I hope it works as expected (I used msvc stl implementation as a base).

---

Patch is 27.42 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/171854.diff


10 Files Affected:

- (modified) lldb/source/Plugins/Language/CPlusPlus/CMakeLists.txt (+1) 
- (modified) lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp (+49-46) 
- (modified) lldb/source/Plugins/Language/CPlusPlus/Generic.h (+8) 
- (added) lldb/source/Plugins/Language/CPlusPlus/GenericStringView.cpp (+131) 
- (modified) lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp (+2-94) 
- (modified) lldb/source/Plugins/Language/CPlusPlus/LibCxx.h (-16) 
- (modified) lldb/source/Plugins/Language/CPlusPlus/MsvcStl.cpp (-63) 
- (modified) lldb/source/Plugins/Language/CPlusPlus/MsvcStl.h (-9) 
- (modified) lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/string_view/TestDataFormatterStdStringView.py (+5) 
- (modified) lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/u8string_view/TestDataFormatterStdU8StringView.py (-2) 


``````````diff
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/Plug...
[truncated]

``````````

</details>


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


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