[Lldb-commits] [lldb] [lldb][DataFormatter] Clean up LibcxxStdMapSyntheticFrontEnd::GetKeyValuePair (PR #97551)
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Wed Jul 3 03:15:28 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-lldb
Author: Michael Buch (Michael137)
<details>
<summary>Changes</summary>
This patch cleans up the core of the `std::map` libc++ formatter.
Depends on https://github.com/llvm/llvm-project/pull/97544 and https://github.com/llvm/llvm-project/pull/97549.
Changes:
* Renamed `m_skip_size` to `m_value_type_offset` to better
describe what it's actually for.
* Made updating `m_skip_size` (now `m_value_type_offset`)
isolated to `GetKeyValuePair` (instead of doing so in the
`GetValueOffset` helper).
* We don't need special logic for the 0th index, so I merged the
two `need_to_skip` branches.
---
Full diff: https://github.com/llvm/llvm-project/pull/97551.diff
1 Files Affected:
- (modified) lldb/source/Plugins/Language/CPlusPlus/LibCxxMap.cpp (+108-102)
``````````diff
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxxMap.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxxMap.cpp
index 44fe294ced722..e12704ce28443 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxxMap.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxxMap.cpp
@@ -17,6 +17,9 @@
#include "lldb/Utility/Endian.h"
#include "lldb/Utility/Status.h"
#include "lldb/Utility/Stream.h"
+#include "lldb/lldb-forward.h"
+#include <cstdint>
+#include <optional>
using namespace lldb;
using namespace lldb_private;
@@ -182,12 +185,28 @@ class LibcxxStdMapSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
private:
bool GetDataType();
- void GetValueOffset(const lldb::ValueObjectSP &node);
+ std::optional<uint32_t> GetValueOffset();
+
+ /// Returns the ValueObject for the __tree_node type that
+ /// holds the key/value pair of the node at index \ref idx.
+ ///
+ /// \param[in] idx The child index that we're looking to get
+ /// the key/value pair for.
+ ///
+ /// \param[in] max_depth The maximum search depth after which
+ /// we stop trying to find the key/value
+ /// pair for.
+ ///
+ /// \returns On success, returns the ValueObjectSP corresponding
+ /// to the __tree_node's __value_ member (which holds
+ /// the key/value pair the formatter wants to display).
+ /// On failure, will return nullptr.
+ ValueObjectSP GetKeyValuePair(size_t idx, size_t max_depth);
ValueObject *m_tree = nullptr;
ValueObject *m_root_node = nullptr;
CompilerType m_element_type;
- uint32_t m_skip_size = UINT32_MAX;
+ uint32_t m_value_type_offset = UINT32_MAX;
size_t m_count = UINT32_MAX;
std::map<size_t, MapIterator> m_iterators;
};
@@ -257,117 +276,105 @@ bool lldb_private::formatters::LibcxxStdMapSyntheticFrontEnd::GetDataType() {
}
}
-void lldb_private::formatters::LibcxxStdMapSyntheticFrontEnd::GetValueOffset(
- const lldb::ValueObjectSP &node) {
- if (m_skip_size != UINT32_MAX)
- return;
- if (!node)
- return;
- CompilerType node_type(node->GetCompilerType());
- uint64_t bit_offset;
- if (node_type.GetIndexOfFieldWithName("__value_", nullptr, &bit_offset) !=
- UINT32_MAX) {
- // Old layout (pre 089a7cc5dea)
- m_skip_size = bit_offset / 8u;
- } else {
- auto ast_ctx = node_type.GetTypeSystem().dyn_cast_or_null<TypeSystemClang>();
- if (!ast_ctx)
- return;
- CompilerType tree_node_type = ast_ctx->CreateStructForIdentifier(
- llvm::StringRef(),
- {{"ptr0", ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
- {"ptr1", ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
- {"ptr2", ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
- {"cw", ast_ctx->GetBasicType(lldb::eBasicTypeBool)},
- {"payload", (m_element_type.GetCompleteType(), m_element_type)}});
- std::string child_name;
- uint32_t child_byte_size;
- int32_t child_byte_offset = 0;
- uint32_t child_bitfield_bit_size;
- uint32_t child_bitfield_bit_offset;
- bool child_is_base_class;
- bool child_is_deref_of_parent;
- uint64_t language_flags;
- auto child_type =
- llvm::expectedToStdOptional(tree_node_type.GetChildCompilerTypeAtIndex(
- nullptr, 4, true, true, true, child_name, child_byte_size,
- child_byte_offset, child_bitfield_bit_size,
- child_bitfield_bit_offset, child_is_base_class,
- child_is_deref_of_parent, nullptr, language_flags));
- if (child_type && child_type->IsValid())
- m_skip_size = (uint32_t)child_byte_offset;
- }
+std::optional<uint32_t>
+lldb_private::formatters::LibcxxStdMapSyntheticFrontEnd::GetValueOffset() {
+ if (!m_tree)
+ return std::nullopt;
+
+ auto ast_ctx = m_tree->GetCompilerType()
+ .GetTypeSystem()
+ .dyn_cast_or_null<TypeSystemClang>();
+ if (!ast_ctx)
+ return std::nullopt;
+
+ CompilerType tree_node_type = ast_ctx->CreateStructForIdentifier(
+ llvm::StringRef(),
+ {{"ptr0", ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
+ {"ptr1", ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
+ {"ptr2", ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
+ {"cw", ast_ctx->GetBasicType(lldb::eBasicTypeBool)},
+ {"payload", (m_element_type.GetCompleteType(), m_element_type)}});
+ std::string child_name;
+ uint32_t child_byte_size;
+ int32_t child_byte_offset = 0;
+ uint32_t child_bitfield_bit_size;
+ uint32_t child_bitfield_bit_offset;
+ bool child_is_base_class;
+ bool child_is_deref_of_parent;
+ uint64_t language_flags;
+ auto child_type =
+ llvm::expectedToStdOptional(tree_node_type.GetChildCompilerTypeAtIndex(
+ nullptr, 4, true, true, true, child_name, child_byte_size,
+ child_byte_offset, child_bitfield_bit_size, child_bitfield_bit_offset,
+ child_is_base_class, child_is_deref_of_parent, nullptr,
+ language_flags));
+
+ if (!child_type || !child_type->IsValid())
+ return std::nullopt;
+
+ return child_byte_offset;
}
-lldb::ValueObjectSP
-lldb_private::formatters::LibcxxStdMapSyntheticFrontEnd::GetChildAtIndex(
- uint32_t idx) {
- static ConstString g_cc_("__cc_"), g_cc("__cc");
- static ConstString g_nc("__nc");
- uint32_t num_children = CalculateNumChildrenIgnoringErrors();
- if (idx >= num_children)
- return lldb::ValueObjectSP();
- if (m_tree == nullptr || m_root_node == nullptr)
- return lldb::ValueObjectSP();
-
- MapIterator iterator(m_root_node, num_children);
+ValueObjectSP
+lldb_private::formatters::LibcxxStdMapSyntheticFrontEnd::GetKeyValuePair(
+ size_t idx, size_t max_depth) {
+ MapIterator iterator(m_root_node, max_depth);
- const bool need_to_skip = (idx > 0);
- size_t actual_advancde = idx;
- if (need_to_skip) {
+ size_t advance_by = idx;
+ if (idx > 0) {
+ // If we have already created the iterator for the previous
+ // index, we can start from there and advance by 1.
auto cached_iterator = m_iterators.find(idx - 1);
if (cached_iterator != m_iterators.end()) {
iterator = cached_iterator->second;
- actual_advancde = 1;
+ advance_by = 1;
}
}
- ValueObjectSP iterated_sp(iterator.advance(actual_advancde));
- if (!iterated_sp) {
+ ValueObjectSP iterated_sp(iterator.advance(advance_by));
+ if (!iterated_sp)
// this tree is garbage - stop
- m_tree =
- nullptr; // this will stop all future searches until an Update() happens
- return iterated_sp;
- }
+ return nullptr;
- if (!GetDataType()) {
- m_tree = nullptr;
- return lldb::ValueObjectSP();
- }
+ if (!GetDataType())
+ return nullptr;
- if (!need_to_skip) {
- Status error;
- iterated_sp = iterated_sp->Dereference(error);
- if (!iterated_sp || error.Fail()) {
- m_tree = nullptr;
- return lldb::ValueObjectSP();
- }
- GetValueOffset(iterated_sp);
- auto child_sp = iterated_sp->GetChildMemberWithName("__value_");
- if (child_sp)
- iterated_sp = child_sp;
+ if (m_value_type_offset == UINT32_MAX) {
+ if (auto offset = GetValueOffset())
+ m_value_type_offset = *offset;
else
- iterated_sp = iterated_sp->GetSyntheticChildAtOffset(
- m_skip_size, m_element_type, true);
- if (!iterated_sp) {
- m_tree = nullptr;
- return lldb::ValueObjectSP();
- }
- } else {
- // because of the way our debug info is made, we need to read item 0
- // first so that we can cache information used to generate other elements
- if (m_skip_size == UINT32_MAX)
- GetChildAtIndex(0);
- if (m_skip_size == UINT32_MAX) {
- m_tree = nullptr;
- return lldb::ValueObjectSP();
- }
- iterated_sp = iterated_sp->GetSyntheticChildAtOffset(m_skip_size,
- m_element_type, true);
- if (!iterated_sp) {
- m_tree = nullptr;
- return lldb::ValueObjectSP();
- }
+ return nullptr;
+ }
+
+ assert(m_value_type_offset != UINT32_MAX);
+
+ iterated_sp = iterated_sp->GetSyntheticChildAtOffset(m_value_type_offset,
+ m_element_type, true);
+ if (!iterated_sp)
+ return nullptr;
+
+ m_iterators[idx] = iterator;
+
+ return iterated_sp;
+}
+
+lldb::ValueObjectSP
+lldb_private::formatters::LibcxxStdMapSyntheticFrontEnd::GetChildAtIndex(
+ uint32_t idx) {
+ static ConstString g_cc_("__cc_"), g_cc("__cc");
+ static ConstString g_nc("__nc");
+ uint32_t num_children = CalculateNumChildrenIgnoringErrors();
+ if (idx >= num_children)
+ return nullptr;
+
+ if (m_tree == nullptr || m_root_node == nullptr)
+ return nullptr;
+
+ ValueObjectSP key_val_sp = GetKeyValuePair(idx, /*max_depth=*/num_children);
+ if (!key_val_sp) {
+ // this will stop all future searches until an Update() happens
+ m_tree = nullptr;
+ return nullptr;
}
// at this point we have a valid
@@ -375,7 +382,7 @@ lldb_private::formatters::LibcxxStdMapSyntheticFrontEnd::GetChildAtIndex(
// all items named __value_
StreamString name;
name.Printf("[%" PRIu64 "]", (uint64_t)idx);
- auto potential_child_sp = iterated_sp->Clone(ConstString(name.GetString()));
+ auto potential_child_sp = key_val_sp->Clone(ConstString(name.GetString()));
if (potential_child_sp) {
switch (potential_child_sp->GetNumChildrenIgnoringErrors()) {
case 1: {
@@ -396,7 +403,6 @@ lldb_private::formatters::LibcxxStdMapSyntheticFrontEnd::GetChildAtIndex(
}
}
}
- m_iterators[idx] = iterator;
return potential_child_sp;
}
``````````
</details>
https://github.com/llvm/llvm-project/pull/97551
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