[Lldb-commits] [lldb] [lldb] Add libstdcpp initializer_list formatter (PR #167515)

via lldb-commits lldb-commits at lists.llvm.org
Tue Nov 11 06:39:37 PST 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: Ebuka Ezike (da-viper)

<details>
<summary>Changes</summary>

Make the existing libc++ formatter generic
Add initializer_list summary provider.
Add test for `libstdcpp`

---
Full diff: https://github.com/llvm/llvm-project/pull/167515.diff


8 Files Affected:

- (modified) lldb/source/Plugins/Language/CPlusPlus/CMakeLists.txt (+1-1) 
- (modified) lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp (+8-5) 
- (modified) lldb/source/Plugins/Language/CPlusPlus/Generic.h (+3) 
- (added) lldb/source/Plugins/Language/CPlusPlus/GenericInitializerList.cpp (+145) 
- (modified) lldb/source/Plugins/Language/CPlusPlus/LibCxx.h (-4) 
- (removed) lldb/source/Plugins/Language/CPlusPlus/LibCxxInitializerList.cpp (-124) 
- (modified) lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/initializer_list/TestDataFormatterStdInitializerList.py (+5) 
- (modified) lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/initializer_list/main.cpp (-1) 


``````````diff
diff --git a/lldb/source/Plugins/Language/CPlusPlus/CMakeLists.txt b/lldb/source/Plugins/Language/CPlusPlus/CMakeLists.txt
index cbc6f149ac303..ca4fd3f680484 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CMakeLists.txt
+++ b/lldb/source/Plugins/Language/CPlusPlus/CMakeLists.txt
@@ -14,11 +14,11 @@ add_lldb_library(lldbPluginCPlusPlusLanguage PLUGIN
   CxxStringTypes.cpp
   Generic.cpp
   GenericBitset.cpp
+  GenericInitializerList.cpp
   GenericList.cpp
   GenericOptional.cpp
   LibCxx.cpp
   LibCxxAtomic.cpp
-  LibCxxInitializerList.cpp
   LibCxxMap.cpp
   LibCxxQueue.cpp
   LibCxxRangesRefView.cpp
diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
index a2199cb65cd35..60b38baebc549 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
@@ -899,11 +899,6 @@ static void LoadLibCxxFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
       "libc++ std::unordered containers synthetic children",
       "^std::__[[:alnum:]]+::unordered_(multi)?(map|set)<.+> >$",
       stl_synth_flags, true);
-  AddCXXSynthetic(
-      cpp_category_sp,
-      lldb_private::formatters::LibcxxInitializerListSyntheticFrontEndCreator,
-      "libc++ std::initializer_list synthetic children",
-      "^std::initializer_list<.+>$", stl_synth_flags, true);
   AddCXXSynthetic(cpp_category_sp, LibcxxQueueFrontEndCreator,
                   "libc++ std::queue synthetic children",
                   "^std::__[[:alnum:]]+::queue<.+>$", stl_synth_flags, true);
@@ -1705,6 +1700,11 @@ static void LoadCommonStlFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
           },
           "MSVC STL/libstdc++ std::wstring summary provider"));
 
+  AddCXXSynthetic(cpp_category_sp,
+                  GenericInitializerListSyntheticFrontEndCreator,
+                  "libc++/libstdc++ std::initializer_list synthetic children",
+                  "^std::initializer_list<.+>$", stl_synth_flags, true);
+
   stl_summary_flags.SetDontShowChildren(false);
   stl_summary_flags.SetSkipPointers(false);
 
@@ -1748,6 +1748,9 @@ static void LoadCommonStlFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
                   "^std::(multi)?(map|set)<.+>(( )?&)?$", stl_synth_flags,
                   true);
 
+  AddCXXSummary(cpp_category_sp, ContainerSizeSummaryProvider,
+                "libc++/libstdc++ std::initializer_list summary provider",
+                "^std::initializer_list<.+>$", stl_summary_flags, true);
   AddCXXSummary(cpp_category_sp, GenericSmartPointerSummaryProvider,
                 "MSVC STL/libstdc++ std::shared_ptr summary provider",
                 "^std::shared_ptr<.+>(( )?&)?$", stl_summary_flags, true);
diff --git a/lldb/source/Plugins/Language/CPlusPlus/Generic.h b/lldb/source/Plugins/Language/CPlusPlus/Generic.h
index f3946225ed48d..539eddd3d3e78 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/Generic.h
+++ b/lldb/source/Plugins/Language/CPlusPlus/Generic.h
@@ -24,6 +24,9 @@ bool GenericOptionalSummaryProvider(ValueObject &valobj, Stream &stream,
 lldb::ValueObjectSP GetDesugaredSmartPointerValue(ValueObject &ptr,
                                                   ValueObject &container);
 
+SyntheticChildrenFrontEnd *
+GenericInitializerListSyntheticFrontEndCreator(CXXSyntheticChildren *,
+                                               lldb::ValueObjectSP valobj_sp);
 } // namespace formatters
 } // namespace lldb_private
 
diff --git a/lldb/source/Plugins/Language/CPlusPlus/GenericInitializerList.cpp b/lldb/source/Plugins/Language/CPlusPlus/GenericInitializerList.cpp
new file mode 100644
index 0000000000000..7f012b7fc8aa6
--- /dev/null
+++ b/lldb/source/Plugins/Language/CPlusPlus/GenericInitializerList.cpp
@@ -0,0 +1,145 @@
+//===-- GenericInitializerList.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 "lldb/DataFormatters/FormattersHelpers.h"
+#include "lldb/Utility/ConstString.h"
+#include "lldb/ValueObject/ValueObject.h"
+#include <cstddef>
+#include <optional>
+#include <type_traits>
+
+using namespace lldb;
+using namespace lldb_private;
+
+namespace generic_check {
+template <class T>
+using size_func = decltype(T::GetSizeMember(std::declval<ValueObject &>()));
+template <class T>
+using start_func = decltype(T::GetStartMember(std::declval<ValueObject &>()));
+namespace {
+template <typename...> struct check_func : std::true_type {};
+} // namespace
+
+template <typename T>
+using has_functions = check_func<size_func<T>, start_func<T>>;
+} // namespace generic_check
+
+struct LibCxx {
+  static ValueObjectSP GetStartMember(ValueObject &backend) {
+    return backend.GetChildMemberWithName("__begin_");
+  }
+
+  static ValueObjectSP GetSizeMember(ValueObject &backend) {
+    return backend.GetChildMemberWithName("__size_");
+  }
+};
+
+struct LibStdcpp {
+  static ValueObjectSP GetStartMember(ValueObject &backend) {
+    return backend.GetChildMemberWithName("_M_array");
+  }
+
+  static ValueObjectSP GetSizeMember(ValueObject &backend) {
+    return backend.GetChildMemberWithName("_M_len");
+  }
+};
+
+namespace lldb_private::formatters {
+
+template <class StandardImpl>
+class GenericInitializerListSyntheticFrontEnd
+    : public SyntheticChildrenFrontEnd {
+public:
+  static_assert(generic_check::has_functions<StandardImpl>::value,
+                "Missing Required Functions.");
+
+  GenericInitializerListSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
+      : SyntheticChildrenFrontEnd(*valobj_sp), m_element_type() {
+    if (valobj_sp)
+      Update();
+  }
+
+  ~GenericInitializerListSyntheticFrontEnd() override {
+    // this needs to stay around because it's a child object who will follow its
+    // parent's life cycle
+    // delete m_start;
+  }
+
+  llvm::Expected<uint32_t> CalculateNumChildren() override {
+    m_num_elements = 0;
+
+    const ValueObjectSP size_sp(StandardImpl::GetSizeMember(m_backend));
+    if (size_sp)
+      m_num_elements = size_sp->GetValueAsUnsigned(0);
+    return m_num_elements;
+  }
+
+  lldb::ValueObjectSP GetChildAtIndex(uint32_t idx) override {
+    if (!m_start)
+      return {};
+
+    uint64_t offset = static_cast<uint64_t>(idx) * m_element_size;
+    offset = offset + m_start->GetValueAsUnsigned(0);
+    StreamString name;
+    name.Printf("[%" PRIu64 "]", (uint64_t)idx);
+    return CreateValueObjectFromAddress(name.GetString(), offset,
+                                        m_backend.GetExecutionContextRef(),
+                                        m_element_type);
+  }
+
+  lldb::ChildCacheState Update() override {
+    m_start = nullptr;
+    m_num_elements = 0;
+    m_element_type = m_backend.GetCompilerType().GetTypeTemplateArgument(0);
+    if (!m_element_type.IsValid())
+      return lldb::ChildCacheState::eRefetch;
+
+    llvm::Expected<uint64_t> size_or_err = m_element_type.GetByteSize(nullptr);
+    if (!size_or_err)
+      LLDB_LOG_ERRORV(GetLog(LLDBLog::DataFormatters), size_or_err.takeError(),
+                      "{0}");
+    else {
+      m_element_size = *size_or_err;
+      // Store raw pointers or end up with a circular dependency.
+      m_start = StandardImpl::GetStartMember(m_backend).get();
+    }
+
+    return lldb::ChildCacheState::eRefetch;
+  }
+
+  llvm::Expected<size_t> GetIndexOfChildWithName(ConstString name) override {
+    if (!m_start) {
+      return llvm::createStringError("Type has no child named '%s'",
+                                     name.AsCString());
+    }
+    auto optional_idx = formatters::ExtractIndexFromString(name.GetCString());
+    if (!optional_idx) {
+      return llvm::createStringError("Type has no child named '%s'",
+                                     name.AsCString());
+    }
+    return *optional_idx;
+  }
+
+private:
+  ValueObject *m_start = nullptr;
+  CompilerType m_element_type;
+  uint32_t m_element_size = 0;
+  size_t m_num_elements = 0;
+};
+
+SyntheticChildrenFrontEnd *GenericInitializerListSyntheticFrontEndCreator(
+    CXXSyntheticChildren * /*unused*/, lldb::ValueObjectSP valobj_sp) {
+  if (!valobj_sp)
+    return nullptr;
+
+  if (LibCxx::GetStartMember(*valobj_sp) != nullptr)
+    return new GenericInitializerListSyntheticFrontEnd<LibCxx>(valobj_sp);
+
+  return new GenericInitializerListSyntheticFrontEnd<LibStdcpp>(valobj_sp);
+}
+} // namespace lldb_private::formatters
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.h b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.h
index 819f8a985f9b9..8fd29288da35f 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.h
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.h
@@ -194,10 +194,6 @@ SyntheticChildrenFrontEnd *
 LibCxxUnorderedMapIteratorSyntheticFrontEndCreator(CXXSyntheticChildren *,
                                                    lldb::ValueObjectSP);
 
-SyntheticChildrenFrontEnd *
-LibcxxInitializerListSyntheticFrontEndCreator(CXXSyntheticChildren *,
-                                              lldb::ValueObjectSP);
-
 SyntheticChildrenFrontEnd *LibcxxQueueFrontEndCreator(CXXSyntheticChildren *,
                                                       lldb::ValueObjectSP);
 
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxxInitializerList.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxxInitializerList.cpp
deleted file mode 100644
index d952688f381f5..0000000000000
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxxInitializerList.cpp
+++ /dev/null
@@ -1,124 +0,0 @@
-//===-- LibCxxInitializerList.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 "LibCxx.h"
-
-#include "lldb/DataFormatters/FormattersHelpers.h"
-#include "lldb/Utility/ConstString.h"
-#include "lldb/ValueObject/ValueObject.h"
-#include <optional>
-
-using namespace lldb;
-using namespace lldb_private;
-using namespace lldb_private::formatters;
-
-namespace lldb_private {
-namespace formatters {
-class LibcxxInitializerListSyntheticFrontEnd
-    : public SyntheticChildrenFrontEnd {
-public:
-  LibcxxInitializerListSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
-
-  ~LibcxxInitializerListSyntheticFrontEnd() override;
-
-  llvm::Expected<uint32_t> CalculateNumChildren() override;
-
-  lldb::ValueObjectSP GetChildAtIndex(uint32_t idx) override;
-
-  lldb::ChildCacheState Update() override;
-
-  llvm::Expected<size_t> GetIndexOfChildWithName(ConstString name) override;
-
-private:
-  ValueObject *m_start = nullptr;
-  CompilerType m_element_type;
-  uint32_t m_element_size = 0;
-  size_t m_num_elements = 0;
-};
-} // namespace formatters
-} // namespace lldb_private
-
-lldb_private::formatters::LibcxxInitializerListSyntheticFrontEnd::
-    LibcxxInitializerListSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
-    : SyntheticChildrenFrontEnd(*valobj_sp), m_element_type() {
-  if (valobj_sp)
-    Update();
-}
-
-lldb_private::formatters::LibcxxInitializerListSyntheticFrontEnd::
-    ~LibcxxInitializerListSyntheticFrontEnd() {
-  // this needs to stay around because it's a child object who will follow its
-  // parent's life cycle
-  // delete m_start;
-}
-
-llvm::Expected<uint32_t> lldb_private::formatters::
-    LibcxxInitializerListSyntheticFrontEnd::CalculateNumChildren() {
-  m_num_elements = 0;
-  ValueObjectSP size_sp(m_backend.GetChildMemberWithName("__size_"));
-  if (size_sp)
-    m_num_elements = size_sp->GetValueAsUnsigned(0);
-  return m_num_elements;
-}
-
-lldb::ValueObjectSP lldb_private::formatters::
-    LibcxxInitializerListSyntheticFrontEnd::GetChildAtIndex(uint32_t idx) {
-  if (!m_start)
-    return lldb::ValueObjectSP();
-
-  uint64_t offset = idx * m_element_size;
-  offset = offset + m_start->GetValueAsUnsigned(0);
-  StreamString name;
-  name.Printf("[%" PRIu64 "]", (uint64_t)idx);
-  return CreateValueObjectFromAddress(name.GetString(), offset,
-                                      m_backend.GetExecutionContextRef(),
-                                      m_element_type);
-}
-
-lldb::ChildCacheState
-lldb_private::formatters::LibcxxInitializerListSyntheticFrontEnd::Update() {
-  m_start = nullptr;
-  m_num_elements = 0;
-  m_element_type = m_backend.GetCompilerType().GetTypeTemplateArgument(0);
-  if (!m_element_type.IsValid())
-    return lldb::ChildCacheState::eRefetch;
-
-  llvm::Expected<uint64_t> size_or_err = m_element_type.GetByteSize(nullptr);
-  if (!size_or_err)
-    LLDB_LOG_ERRORV(GetLog(LLDBLog::DataFormatters), size_or_err.takeError(),
-                    "{0}");
-  else {
-    m_element_size = *size_or_err;
-    // Store raw pointers or end up with a circular dependency.
-    m_start = m_backend.GetChildMemberWithName("__begin_").get();
-  }
-
-  return lldb::ChildCacheState::eRefetch;
-}
-
-llvm::Expected<size_t>
-lldb_private::formatters::LibcxxInitializerListSyntheticFrontEnd::
-    GetIndexOfChildWithName(ConstString name) {
-  if (!m_start) {
-    return llvm::createStringError("Type has no child named '%s'",
-                                   name.AsCString());
-  }
-  auto optional_idx = formatters::ExtractIndexFromString(name.GetCString());
-  if (!optional_idx) {
-    return llvm::createStringError("Type has no child named '%s'",
-                                   name.AsCString());
-  }
-  return *optional_idx;
-}
-
-lldb_private::SyntheticChildrenFrontEnd *
-lldb_private::formatters::LibcxxInitializerListSyntheticFrontEndCreator(
-    CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
-  return (valobj_sp ? new LibcxxInitializerListSyntheticFrontEnd(valobj_sp)
-                    : nullptr);
-}
diff --git a/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/initializer_list/TestDataFormatterStdInitializerList.py b/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/initializer_list/TestDataFormatterStdInitializerList.py
index 133f8f7d56b68..c618ebc252e3f 100644
--- a/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/initializer_list/TestDataFormatterStdInitializerList.py
+++ b/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/initializer_list/TestDataFormatterStdInitializerList.py
@@ -38,3 +38,8 @@ def do_test(self):
     def test_libcxx(self):
         self.build(dictionary={"USE_LIBCPP": 1})
         self.do_test()
+
+    @add_test_categories(["libstdcxx"])
+    def test_libstdcpp(self):
+        self.build(dictionary={"USE_LIBSTDCPP": 1})
+        self.do_test()
diff --git a/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/initializer_list/main.cpp b/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/initializer_list/main.cpp
index a9d159e0be28a..7c62cac4a0bcb 100644
--- a/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/initializer_list/main.cpp
+++ b/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/initializer_list/main.cpp
@@ -1,6 +1,5 @@
 #include <initializer_list>
 #include <string>
-#include <vector>
 
 int main() {
   std::initializer_list<int> ili{1, 2, 3, 4, 5};

``````````

</details>


https://github.com/llvm/llvm-project/pull/167515


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