[Lldb-commits] [lldb] [lldb][DataFormatters] Support newer _LIBCPP_COMPRESSED_PAIR layouts (PR #155153)
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Sun Aug 24 02:26:32 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-lldb
Author: Michael Buch (Michael137)
<details>
<summary>Changes</summary>
Starting with https://github.com/llvm/llvm-project/pull/154686 the compressed_pair children are now wrapped in an anonymous structure.
This patch adjusts the LLDB data-formatters to support that.
---
Full diff: https://github.com/llvm/llvm-project/pull/155153.diff
6 Files Affected:
- (modified) lldb/source/Plugins/Language/CPlusPlus/GenericList.cpp (+12-12)
- (modified) lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp (+35-2)
- (modified) lldb/source/Plugins/Language/CPlusPlus/LibCxx.h (+16-1)
- (modified) lldb/source/Plugins/Language/CPlusPlus/LibCxxMap.cpp (+13-16)
- (modified) lldb/source/Plugins/Language/CPlusPlus/LibCxxUnorderedMap.cpp (+22-37)
- (modified) lldb/source/Plugins/Language/CPlusPlus/LibCxxVector.cpp (+5-7)
``````````diff
diff --git a/lldb/source/Plugins/Language/CPlusPlus/GenericList.cpp b/lldb/source/Plugins/Language/CPlusPlus/GenericList.cpp
index ea1edbfd3ac9b..5289027fbd8af 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/GenericList.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/GenericList.cpp
@@ -339,11 +339,18 @@ lldb::ChildCacheState LibCxxForwardListFrontEnd::Update() {
if (err.Fail() || !backend_addr)
return lldb::ChildCacheState::eRefetch;
- ValueObjectSP impl_sp(m_backend.GetChildMemberWithName("__before_begin_"));
+ auto list_base_sp = m_backend.GetChildAtIndex(0);
+ if (!list_base_sp)
+ return lldb::ChildCacheState::eRefetch;
+
+ // Anonymous strucutre index is in base class at index 0.
+ auto [impl_sp, is_compressed_pair] =
+ GetValueOrOldCompressedPair(*list_base_sp, /*anon_struct_idx=*/0,
+ "__before_begin_", "__before_begin_");
if (!impl_sp)
return ChildCacheState::eRefetch;
- if (isOldCompressedPairLayout(*impl_sp))
+ if (is_compressed_pair)
impl_sp = GetFirstValueOfLibCXXCompressedPair(*impl_sp);
if (!impl_sp)
@@ -366,17 +373,10 @@ llvm::Expected<uint32_t> LibCxxListFrontEnd::CalculateNumChildren() {
if (!m_head || !m_tail || m_node_address == 0)
return 0;
- ValueObjectSP size_node_sp(m_backend.GetChildMemberWithName("__size_"));
- if (!size_node_sp) {
- size_node_sp = m_backend.GetChildMemberWithName(
- "__size_alloc_"); // pre-compressed_pair rework
-
- if (!isOldCompressedPairLayout(*size_node_sp))
- return llvm::createStringError("Unexpected std::list layout: expected "
- "old __compressed_pair layout.");
-
+ auto [size_node_sp, is_compressed_pair] = GetValueOrOldCompressedPair(
+ m_backend, /*anon_struct_idx=*/1, "__size_", "__size_alloc_");
+ if (is_compressed_pair)
size_node_sp = GetFirstValueOfLibCXXCompressedPair(*size_node_sp);
- }
if (size_node_sp)
m_count = size_node_sp->GetValueAsUnsigned(UINT32_MAX);
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
index a7874047942c4..6d41132122641 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
@@ -49,8 +49,7 @@ static void consumeInlineNamespace(llvm::StringRef &name) {
}
}
-bool lldb_private::formatters::isOldCompressedPairLayout(
- ValueObject &pair_obj) {
+static bool isOldCompressedPairLayout(ValueObject &pair_obj) {
return isStdTemplate(pair_obj.GetTypeName(), "__compressed_pair");
}
@@ -105,6 +104,40 @@ lldb_private::formatters::GetSecondValueOfLibCXXCompressedPair(
return value;
}
+std::pair<lldb::ValueObjectSP, bool>
+lldb_private::formatters::GetValueOrOldCompressedPair(
+ ValueObject &obj, size_t anon_struct_idx, llvm::StringRef child_name,
+ llvm::StringRef compressed_pair_name) {
+ // Try searching the child member in an anonymous structure first.
+ if (auto unwrapped = obj.GetChildAtIndex(anon_struct_idx)) {
+ ValueObjectSP node_sp(obj.GetChildMemberWithName(child_name));
+ if (node_sp)
+ return {node_sp, isOldCompressedPairLayout(*node_sp)};
+ }
+
+ // Older versions of libc++ don't wrap the children in anonymous structures.
+ // Try that instead.
+ ValueObjectSP node_sp(obj.GetChildMemberWithName(child_name));
+ if (node_sp)
+ return {node_sp, isOldCompressedPairLayout(*node_sp)};
+
+ // Try the even older __compressed_pair layout.
+
+ assert(!compressed_pair_name.empty());
+
+ node_sp = obj.GetChildMemberWithName(compressed_pair_name);
+
+ // Unrecognized layout (possibly older than LLDB supports).
+ if (!node_sp)
+ return {nullptr, false};
+
+ // Expected old compressed_pair layout, but got something else.
+ if (!isOldCompressedPairLayout(*node_sp))
+ return {nullptr, false};
+
+ return {node_sp, true};
+}
+
bool lldb_private::formatters::LibcxxFunctionSummaryProvider(
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 d88a6ecb1fa89..819f8a985f9b9 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.h
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.h
@@ -25,7 +25,22 @@ GetChildMemberWithName(ValueObject &obj,
lldb::ValueObjectSP GetFirstValueOfLibCXXCompressedPair(ValueObject &pair);
lldb::ValueObjectSP GetSecondValueOfLibCXXCompressedPair(ValueObject &pair);
-bool isOldCompressedPairLayout(ValueObject &pair_obj);
+
+/// Returns the ValueObjectSP of the child of \c obj. If \c obj has no
+/// child named \c child_name, returns the __compressed_pair child instead
+/// with \c compressed_pair_name, if one exists.
+///
+/// Latest libc++ wrap the compressed children in an anonymous structure.
+/// The \c anon_struct_idx indicates the location of this struct.
+///
+/// The returned boolean is \c true if the returned child was has an old-style
+/// libc++ __compressed_pair layout.
+///
+/// If no child was found returns a nullptr.
+std::pair<lldb::ValueObjectSP, bool>
+GetValueOrOldCompressedPair(ValueObject &obj, size_t anon_struct_idx,
+ llvm::StringRef child_name,
+ llvm::StringRef compressed_pair_name);
bool isStdTemplate(ConstString type_name, llvm::StringRef type);
bool LibcxxStringSummaryProviderASCII(
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxxMap.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxxMap.cpp
index 41441dfbc7180..85766966f1554 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxxMap.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxxMap.cpp
@@ -200,7 +200,8 @@ class LibcxxStdMapSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
llvm::Expected<size_t> GetIndexOfChildWithName(ConstString name) override;
private:
- llvm::Expected<uint32_t> CalculateNumChildrenForOldCompressedPairLayout();
+ llvm::Expected<uint32_t>
+ CalculateNumChildrenForOldCompressedPairLayout(ValueObject &pair);
/// Returns the ValueObject for the __tree_node type that
/// holds the key/value pair of the node at index \ref idx.
@@ -254,16 +255,8 @@ lldb_private::formatters::LibcxxStdMapSyntheticFrontEnd::
llvm::Expected<uint32_t>
lldb_private::formatters::LibcxxStdMapSyntheticFrontEnd::
- CalculateNumChildrenForOldCompressedPairLayout() {
- ValueObjectSP node_sp(m_tree->GetChildMemberWithName("__pair3_"));
- if (!node_sp)
- return 0;
-
- if (!isOldCompressedPairLayout(*node_sp))
- return llvm::createStringError("Unexpected std::map layout: expected "
- "old __compressed_pair layout.");
-
- node_sp = GetFirstValueOfLibCXXCompressedPair(*node_sp);
+ CalculateNumChildrenForOldCompressedPairLayout(ValueObject &pair) {
+ auto node_sp = GetFirstValueOfLibCXXCompressedPair(pair);
if (!node_sp)
return 0;
@@ -281,12 +274,16 @@ llvm::Expected<uint32_t> lldb_private::formatters::
if (m_tree == nullptr)
return 0;
- if (auto node_sp = m_tree->GetChildMemberWithName("__size_")) {
- m_count = node_sp->GetValueAsUnsigned(0);
- return m_count;
- }
+ auto [size_sp, is_compressed_pair] = GetValueOrOldCompressedPair(
+ *m_tree, /*anon_struct_idx=*/2, "__size_", "__pair3_");
+ if (!size_sp)
+ return llvm::createStringError("Unexpected std::map layout");
- return CalculateNumChildrenForOldCompressedPairLayout();
+ if (is_compressed_pair)
+ return CalculateNumChildrenForOldCompressedPairLayout(*size_sp);
+
+ m_count = size_sp->GetValueAsUnsigned(0);
+ return m_count;
}
ValueObjectSP
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxxUnorderedMap.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxxUnorderedMap.cpp
index 501fd0945b82c..f88a5319068a2 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxxUnorderedMap.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxxUnorderedMap.cpp
@@ -130,22 +130,17 @@ CompilerType lldb_private::formatters::LibcxxStdUnorderedMapSyntheticFrontEnd::
CompilerType lldb_private::formatters::LibcxxStdUnorderedMapSyntheticFrontEnd::
GetNodeType() {
- auto node_sp = m_backend.GetChildAtNamePath({"__table_", "__first_node_"});
-
- if (!node_sp) {
- auto p1_sp = m_backend.GetChildAtNamePath({"__table_", "__p1_"});
- if (!p1_sp)
- return {};
+ auto table_sp = m_backend.GetChildMemberWithName("__table_");
+ if (!table_sp)
+ return {};
- if (!isOldCompressedPairLayout(*p1_sp))
- return {};
+ auto [node_sp, is_compressed_pair] = GetValueOrOldCompressedPair(
+ *table_sp, /*anon_struct_idx=*/1, "__first_node_", "__p1_");
+ if (is_compressed_pair)
+ node_sp = GetFirstValueOfLibCXXCompressedPair(*node_sp);
- node_sp = GetFirstValueOfLibCXXCompressedPair(*p1_sp);
- if (!node_sp)
- return {};
- }
-
- assert(node_sp);
+ if (!node_sp)
+ return {};
return node_sp->GetCompilerType().GetTypeTemplateArgument(0).GetPointeeType();
}
@@ -223,19 +218,15 @@ lldb::ValueObjectSP lldb_private::formatters::
llvm::Expected<size_t>
lldb_private::formatters::LibcxxStdUnorderedMapSyntheticFrontEnd::
CalculateNumChildrenImpl(ValueObject &table) {
- if (auto size_sp = table.GetChildMemberWithName("__size_"))
+ auto [size_sp, is_compressed_pair] = GetValueOrOldCompressedPair(
+ table, /*anon_struct_idx=*/2, "__size_", "__p2_");
+ if (!is_compressed_pair && size_sp)
return size_sp->GetValueAsUnsigned(0);
- ValueObjectSP p2_sp = table.GetChildMemberWithName("__p2_");
- if (!p2_sp)
- return llvm::createStringError(
- "Unexpected std::unordered_map layout: __p2_ member not found.");
+ if (!is_compressed_pair)
+ return llvm::createStringError("Unsupported std::unordered_map layout.");
- if (!isOldCompressedPairLayout(*p2_sp))
- return llvm::createStringError("Unexpected std::unordered_map layout: old "
- "__compressed_pair layout not found.");
-
- ValueObjectSP num_elements_sp = GetFirstValueOfLibCXXCompressedPair(*p2_sp);
+ ValueObjectSP num_elements_sp = GetFirstValueOfLibCXXCompressedPair(*size_sp);
if (!num_elements_sp)
return llvm::createStringError(
@@ -246,19 +237,13 @@ lldb_private::formatters::LibcxxStdUnorderedMapSyntheticFrontEnd::
}
static ValueObjectSP GetTreePointer(ValueObject &table) {
- ValueObjectSP tree_sp = table.GetChildMemberWithName("__first_node_");
- if (!tree_sp) {
- ValueObjectSP p1_sp = table.GetChildMemberWithName("__p1_");
- if (!p1_sp)
- return nullptr;
-
- if (!isOldCompressedPairLayout(*p1_sp))
- return nullptr;
-
- tree_sp = GetFirstValueOfLibCXXCompressedPair(*p1_sp);
- if (!tree_sp)
- return nullptr;
- }
+ auto [tree_sp, is_compressed_pair] = GetValueOrOldCompressedPair(
+ table, /*anon_struct_idx=*/1, "__first_node_", "__p1_");
+ if (is_compressed_pair)
+ tree_sp = GetFirstValueOfLibCXXCompressedPair(*tree_sp);
+
+ if (!tree_sp)
+ return nullptr;
return tree_sp->GetChildMemberWithName("__next_");
}
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxxVector.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxxVector.cpp
index 4bcdf01c221a3..60913e5c1ac56 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxxVector.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxxVector.cpp
@@ -126,17 +126,15 @@ lldb_private::formatters::LibcxxStdVectorSyntheticFrontEnd::GetChildAtIndex(
}
static ValueObjectSP GetDataPointer(ValueObject &root) {
- if (auto cap_sp = root.GetChildMemberWithName("__cap_"))
- return cap_sp;
-
- ValueObjectSP cap_sp = root.GetChildMemberWithName("__end_cap_");
+ auto [cap_sp, is_compressed_pair] = GetValueOrOldCompressedPair(
+ root, /*anon_struct_idx=*/2, "__cap_", "__end_cap_");
if (!cap_sp)
return nullptr;
- if (!isOldCompressedPairLayout(*cap_sp))
- return nullptr;
+ if (is_compressed_pair)
+ return GetFirstValueOfLibCXXCompressedPair(*cap_sp);
- return GetFirstValueOfLibCXXCompressedPair(*cap_sp);
+ return cap_sp;
}
lldb::ChildCacheState
``````````
</details>
https://github.com/llvm/llvm-project/pull/155153
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