Revert PeekDIEName related patch

Summary:
Revert "[lldb][DWARFUnit] Implement PeekDIEName query (llvm#78486)"

This reverts commit 4684507.

Revert "[lldb][DWARFIndex] Use IDX_parent to implement GetFullyQualifiedType query (llvm#79932)"

This reverts commit 91f4a84.

Note(toyang): added back the DWARFDeclContext arrayref constructor

Author: kusmour

lldb/source/Plugins/SymbolFile/DWARF/DWARFFormValue.cpp

@@ -18,6 +18,8 @@
 #include "DWARFFormValue.h"
 #include "DWARFUnit.h"
 
+class DWARFUnit;
+
 using namespace lldb_private;
 using namespace lldb_private::dwarf;
 using namespace lldb_private::plugin::dwarf;
@@ -500,8 +502,7 @@ dw_addr_t DWARFFormValue::Address() const {
       &offset, index_size);
 }
 
-std::pair<DWARFUnit *, uint64_t>
-DWARFFormValue::ReferencedUnitAndOffset() const {
+DWARFDIE DWARFFormValue::Reference() const {
   uint64_t value = m_value.value.uval;
   switch (m_form) {
   case DW_FORM_ref1:
@@ -515,9 +516,9 @@ DWARFFormValue::ReferencedUnitAndOffset() const {
     if (!m_unit->ContainsDIEOffset(value)) {
       m_unit->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
           "DW_FORM_ref* DIE reference {0:x16} is outside of its CU", value);
-      return {nullptr, 0};
+      return {};
     }
-    return {const_cast<DWARFUnit *>(m_unit), value};
+    return const_cast<DWARFUnit *>(m_unit)->GetDIE(value);
 
   case DW_FORM_ref_addr: {
     DWARFUnit *ref_cu =
@@ -526,29 +527,24 @@ DWARFFormValue::ReferencedUnitAndOffset() const {
     if (!ref_cu) {
       m_unit->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
           "DW_FORM_ref_addr DIE reference {0:x16} has no matching CU", value);
-      return {nullptr, 0};
+      return {};
     }
-    return {ref_cu, value};
+    return ref_cu->GetDIE(value);
   }
 
   case DW_FORM_ref_sig8: {
     DWARFTypeUnit *tu =
         m_unit->GetSymbolFileDWARF().DebugInfo().GetTypeUnitForHash(value);
     if (!tu)
-      return {nullptr, 0};
-    return {tu, tu->GetTypeOffset()};
+      return {};
+    return tu->GetDIE(tu->GetTypeOffset());
   }
 
   default:
-    return {nullptr, 0};
+    return {};
   }
 }
 
-DWARFDIE DWARFFormValue::Reference() const {
-  auto [unit, offset] = ReferencedUnitAndOffset();
-  return unit ? unit->GetDIE(offset) : DWARFDIE();
-}
-
 uint64_t DWARFFormValue::Reference(dw_offset_t base_offset) const {
   uint64_t value = m_value.value.uval;
   switch (m_form) {

lldb/source/Plugins/SymbolFile/DWARF/DWARFFormValue.h

@@ -60,12 +60,6 @@ class DWARFFormValue {
                                              const DWARFUnit *u);
   std::optional<uint8_t> GetFixedSize() const;
   DWARFDIE Reference() const;
-
-  /// If this is a reference to another DIE, return the corresponding DWARFUnit
-  /// and DIE offset such that Unit->GetDIE(offset) produces the desired DIE.
-  /// Otherwise, a nullptr and unspecified offset are returned.
-  std::pair<DWARFUnit *, uint64_t> ReferencedUnitAndOffset() const;
-
   uint64_t Reference(dw_offset_t offset) const;
   bool Boolean() const { return m_value.value.uval != 0; }
   uint64_t Unsigned() const { return m_value.value.uval; }

lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp

@@ -670,30 +670,6 @@ DWARFUnit::GetDIE(dw_offset_t die_offset) {
   return DWARFDIE(); // Not found
 }
 
-llvm::StringRef DWARFUnit::PeekDIEName(dw_offset_t die_offset) {
-  DWARFDebugInfoEntry die;
-  if (!die.Extract(GetData(), *this, &die_offset))
-    return llvm::StringRef();
-
-  // Does die contain a DW_AT_Name?
-  if (const char *name =
-          die.GetAttributeValueAsString(this, DW_AT_name, nullptr))
-    return name;
-
-  // Does its DW_AT_specification or DW_AT_abstract_origin contain an AT_Name?
-  for (auto attr : {DW_AT_specification, DW_AT_abstract_origin}) {
-    DWARFFormValue form_value;
-    if (!die.GetAttributeValue(this, attr, form_value))
-      continue;
-    auto [unit, offset] = form_value.ReferencedUnitAndOffset();
-    if (unit)
-      if (auto name = unit->PeekDIEName(offset); !name.empty())
-        return name;
-  }
-
-  return llvm::StringRef();
-}
-
 DWARFUnit &DWARFUnit::GetNonSkeletonUnit() {
   ExtractUnitDIEIfNeeded();
   if (m_dwo)

lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h

@@ -145,11 +145,6 @@ class DWARFUnit : public UserID {
 
   DWARFDIE GetDIE(dw_offset_t die_offset);
 
-  /// Returns the AT_Name of the DIE at `die_offset`, if it exists, without
-  /// parsing the entire compile unit. An empty is string is returned upon
-  /// error or if the attribute is not present.
-  llvm::StringRef PeekDIEName(dw_offset_t die_offset);
-
   DWARFUnit &GetNonSkeletonUnit();
 
   static uint8_t GetAddressByteSize(const DWARFUnit *cu);

lldb/source/Plugins/SymbolFile/DWARF/DebugNamesDWARFIndex.cpp

@@ -14,7 +14,6 @@
 #include "lldb/Core/Module.h"
 #include "lldb/Utility/RegularExpression.h"
 #include "lldb/Utility/Stream.h"
-#include "llvm/ADT/Sequence.h"
 #include <optional>
 
 using namespace lldb_private;
@@ -329,79 +328,6 @@ getParentChain(Entry entry, uint32_t max_parents) {
 }
 } // namespace
 
-void DebugNamesDWARFIndex::GetFullyQualifiedType(
-    const DWARFDeclContext &context,
-    llvm::function_ref<bool(DWARFDIE die)> callback) {
-  if (context.GetSize() == 0)
-    return;
-
-  llvm::StringRef leaf_name = context[0].name;
-  llvm::SmallVector<llvm::StringRef> parent_names;
-  for (auto idx : llvm::seq<int>(1, context.GetSize()))
-    parent_names.emplace_back(context[idx].name);
-
-  // For each entry, grab its parent chain and check if we have a match.
-  for (const DebugNames::Entry &entry :
-       m_debug_names_up->equal_range(leaf_name)) {
-    if (!isType(entry.tag()))
-      continue;
-
-    // If we get a NULL foreign_tu back, the entry doesn't match the type unit
-    // in the .dwp file, or we were not able to load the .dwo file or the DWO ID
-    // didn't match.
-    std::optional<DWARFTypeUnit *> foreign_tu = GetForeignTypeUnit(entry);
-    if (foreign_tu && foreign_tu.value() == nullptr)
-      continue;
-
-    // Grab at most one extra parent, subsequent parents are not necessary to
-    // test equality.
-    std::optional<llvm::SmallVector<Entry, 4>> parent_chain =
-        getParentChain(entry, parent_names.size() + 1);
-
-    if (!parent_chain) {
-      // Fallback: use the base class implementation.
-      if (!ProcessEntry(entry, [&](DWARFDIE die) {
-            return GetFullyQualifiedTypeImpl(context, die, callback);
-          }))
-        return;
-      continue;
-    }
-
-    if (SameParentChain(parent_names, *parent_chain) &&
-        !ProcessEntry(entry, callback))
-      return;
-  }
-  m_fallback.GetFullyQualifiedType(context, callback);
-}
-
-bool DebugNamesDWARFIndex::SameParentChain(
-    llvm::ArrayRef<llvm::StringRef> parent_names,
-    llvm::ArrayRef<DebugNames::Entry> parent_entries) const {
-
-  if (parent_entries.size() != parent_names.size())
-    return false;
-
-  auto SameAsEntryATName = [this](llvm::StringRef name,
-                                  const DebugNames::Entry &entry) {
-    // Peek at the AT_name of `entry` and test equality to `name`.
-    auto maybe_dieoffset = entry.getDIEUnitOffset();
-    if (!maybe_dieoffset)
-      return false;
-    DWARFUnit *unit = GetNonSkeletonUnit(entry);
-    if (!unit)
-      return false;
-    return name == unit->PeekDIEName(unit->GetOffset() + *maybe_dieoffset);
-  };
-
-  // If the AT_name of any parent fails to match the expected name, we don't
-  // have a match.
-  for (auto [parent_name, parent_entry] :
-       llvm::zip_equal(parent_names, parent_entries))
-    if (!SameAsEntryATName(parent_name, parent_entry))
-      return false;
-  return true;
-}
-
 void DebugNamesDWARFIndex::GetTypes(
     ConstString name, llvm::function_ref<bool(DWARFDIE die)> callback) {
   for (const DebugNames::Entry &entry :

lldb/source/Plugins/SymbolFile/DWARF/DebugNamesDWARFIndex.h

@@ -41,11 +41,6 @@ class DebugNamesDWARFIndex : public DWARFIndex {
   void GetCompleteObjCClass(
       ConstString class_name, bool must_be_implementation,
       llvm::function_ref<bool(DWARFDIE die)> callback) override;
-
-  /// Uses DWARF5's IDX_parent fields, when available, to speed up this query.
-  void GetFullyQualifiedType(
-      const DWARFDeclContext &context,
-      llvm::function_ref<bool(DWARFDIE die)> callback) override;
   void GetTypes(ConstString name,
                 llvm::function_ref<bool(DWARFDIE die)> callback) override;
   void GetTypes(const DWARFDeclContext &context,
@@ -114,10 +109,6 @@ class DebugNamesDWARFIndex : public DWARFIndex {
   bool ProcessEntry(const DebugNames::Entry &entry,
                     llvm::function_ref<bool(DWARFDIE die)> callback);
 
-  /// Returns true if `parent_entries` have identical names to `parent_names`.
-  bool SameParentChain(llvm::ArrayRef<llvm::StringRef> parent_names,
-                       llvm::ArrayRef<DebugNames::Entry> parent_entries) const;
-
   static void MaybeLogLookupError(llvm::Error error,
                                   const DebugNames::NameIndex &ni,
                                   llvm::StringRef name);

lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h

@@ -367,9 +367,6 @@ class SymbolFileDWARF : public SymbolFileCommon {
 
   Type *ResolveTypeUID(const DIERef &die_ref);
 
-  /// Returns the DWARFIndex for this symbol, if it exists.
-  DWARFIndex *getIndex() { return m_index.get(); }
-
 protected:
   SymbolFileDWARF(const SymbolFileDWARF &) = delete;
   const SymbolFileDWARF &operator=(const SymbolFileDWARF &) = delete;

lldb/unittests/SymbolFile/DWARF/CMakeLists.txt

@@ -1,6 +1,5 @@
 add_lldb_unittest(SymbolFileDWARFTests
   DWARFASTParserClangTests.cpp
-  DWARFDebugNamesIndexTest.cpp
   DWARFDIETest.cpp
   DWARFIndexCachingTest.cpp
   DWARFUnitTest.cpp

lldb/unittests/SymbolFile/DWARF/DWARFDIETest.cpp

@@ -111,87 +111,6 @@ TEST(DWARFDIETest, ChildIteration) {
   EXPECT_TRUE(no_children_die.children().empty());
 }
 
-TEST(DWARFDIETest, PeekName) {
-  const char *yamldata = R"(
---- !ELF
-FileHeader:
-  Class:   ELFCLASS64
-  Data:    ELFDATA2LSB
-  Type:    ET_EXEC
-  Machine: EM_386
-DWARF:
-  debug_str:
-    - 'NameType1'
-    - 'NameType2'
-  debug_abbrev:
-    - Table:
-        - Code:            0x00000001
-          Tag:             DW_TAG_compile_unit
-          Children:        DW_CHILDREN_yes
-          Attributes:
-            - Attribute:       DW_AT_language
-              Form:            DW_FORM_data2
-        - Code:            0x00000002
-          Tag:             DW_TAG_base_type
-          Children:        DW_CHILDREN_no
-          Attributes:
-            - Attribute:       DW_AT_name
-              Form:            DW_FORM_strp
-        - Code:            0x00000003
-          Tag:             DW_TAG_base_type
-          Children:        DW_CHILDREN_no
-          Attributes:
-            - Attribute:       DW_AT_abstract_origin
-              Form:            DW_FORM_ref1
-        - Code:            0x00000004
-          Tag:             DW_TAG_base_type
-          Children:        DW_CHILDREN_no
-          Attributes:
-            - Attribute:       DW_AT_specification
-              Form:            DW_FORM_ref1
-  debug_info:
-    - Version:         4
-      AddrSize:        8
-      Entries:
-        - AbbrCode:        0x00000001
-          Values:
-            - Value:           0x000000000000000C
-        - AbbrCode:        0x00000002
-          Values:
-            - Value:           0x0000000000000000 # Name = NameType1
-        - AbbrCode:        0x00000002
-          Values:
-            - Value:           0x000000000000000a # Name = NameType2
-        - AbbrCode:        0x00000003
-          Values:
-            - Value:           0x000000000000000e # Ref abstract origin to NameType1 DIE.
-        - AbbrCode:        0x00000004
-          Values:
-            - Value:           0x0000000000000013 # Ref specification to NameType2 DIE.
-        - AbbrCode:        0x00000000
-)";
-
-  YAMLModuleTester t(yamldata);
-  auto *symbol_file =
-      llvm::cast<SymbolFileDWARF>(t.GetModule()->GetSymbolFile());
-  DWARFUnit *unit = symbol_file->DebugInfo().GetUnitAtIndex(0);
-
-  dw_offset_t first_die_offset = 11;
-  EXPECT_EQ(unit->PeekDIEName(first_die_offset), "");
-
-  dw_offset_t second_die_offset = 14;
-  EXPECT_EQ(unit->PeekDIEName(second_die_offset), "NameType1");
-
-  dw_offset_t third_die_offset = 19;
-  EXPECT_EQ(unit->PeekDIEName(third_die_offset), "NameType2");
-
-  dw_offset_t fourth_die_offset = 24;
-  EXPECT_EQ(unit->PeekDIEName(fourth_die_offset), "NameType1");
-
-  dw_offset_t fifth_die_offset = 26;
-  EXPECT_EQ(unit->PeekDIEName(fifth_die_offset), "NameType2");
-}
-
 TEST(DWARFDIETest, GetContext) {
   const char *yamldata = R"(
 --- !ELF