[lldb/dwarf] Fix DW_IDX_parent processing for split dwarf

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

@@ -259,9 +259,3 @@ DWARFDebugInfo::GetDIE(const DIERef &die_ref) {
     return cu->GetNonSkeletonUnit().GetDIE(die_ref.die_offset());
   return DWARFDIE(); // Not found
 }
-
-llvm::StringRef DWARFDebugInfo::PeekDIEName(const DIERef &die_ref) {
-  if (DWARFUnit *cu = GetUnit(die_ref))
-    return cu->GetNonSkeletonUnit().PeekDIEName(die_ref.die_offset());
-  return llvm::StringRef();
-}

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

@@ -44,11 +44,6 @@ class DWARFDebugInfo {
   bool ContainsTypeUnits();
   DWARFDIE GetDIE(const DIERef &die_ref);
 
-  /// Returns the AT_Name of this DIE, 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(const DIERef &die_ref);
-
   enum {
     eDumpFlag_Verbose = (1 << 0),  // Verbose dumping
     eDumpFlag_ShowForm = (1 << 1), // Show the DW_form type

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

@@ -48,26 +48,30 @@ DebugNamesDWARFIndex::GetUnits(const DebugNames &debug_names) {
   return result;
 }
 
-std::optional<DIERef>
-DebugNamesDWARFIndex::ToDIERef(const DebugNames::Entry &entry) const {
+DWARFUnit *
+DebugNamesDWARFIndex::GetNonSkeletonUnit(const DebugNames::Entry &entry) const {
   // Look for a DWARF unit offset (CU offset or local TU offset) as they are
   // both offsets into the .debug_info section.
   std::optional<uint64_t> unit_offset = entry.getCUOffset();
   if (!unit_offset) {
     unit_offset = entry.getLocalTUOffset();
     if (!unit_offset)
-      return std::nullopt;
+      return nullptr;
   }
 
   DWARFUnit *cu =
       m_debug_info.GetUnitAtOffset(DIERef::Section::DebugInfo, *unit_offset);
-  if (!cu)
-    return std::nullopt;
+  return cu ? &cu->GetNonSkeletonUnit() : nullptr;
+}
 
-  cu = &cu->GetNonSkeletonUnit();
+std::optional<DIERef>
+DebugNamesDWARFIndex::ToDIERef(const DebugNames::Entry &entry) const {
+  DWARFUnit *unit = GetNonSkeletonUnit(entry);
+  if (!unit)
+    return std::nullopt;
   if (std::optional<uint64_t> die_offset = entry.getDIEUnitOffset())
-    return DIERef(cu->GetSymbolFileDWARF().GetFileIndex(),
-                  DIERef::Section::DebugInfo, cu->GetOffset() + *die_offset);
+    return DIERef(unit->GetSymbolFileDWARF().GetFileIndex(),
+                  DIERef::Section::DebugInfo, unit->GetOffset() + *die_offset);
 
   return std::nullopt;
 }
@@ -306,10 +310,10 @@ bool DebugNamesDWARFIndex::SameParentChain(
     auto maybe_dieoffset = entry.getDIEUnitOffset();
     if (!maybe_dieoffset)
       return false;
-    auto die_ref = ToDIERef(entry);
-    if (!die_ref)
+    DWARFUnit *unit = GetNonSkeletonUnit(entry);
+    if (!unit)
       return false;
-    return name == m_debug_info.PeekDIEName(*die_ref);
+    return name == unit->PeekDIEName(unit->GetOffset() + *maybe_dieoffset);
   };
 
   // If the AT_name of any parent fails to match the expected name, we don't

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

@@ -84,6 +84,7 @@ class DebugNamesDWARFIndex : public DWARFIndex {
   std::unique_ptr<DebugNames> m_debug_names_up;
   ManualDWARFIndex m_fallback;
 
+  DWARFUnit *GetNonSkeletonUnit(const DebugNames::Entry &entry) const;
   std::optional<DIERef> ToDIERef(const DebugNames::Entry &entry) const;
   bool ProcessEntry(const DebugNames::Entry &entry,
                     llvm::function_ref<bool(DWARFDIE die)> callback);

lldb/test/API/lang/cpp/limit-debug-info/Makefile

@@ -1,5 +1,3 @@
 CXX_SOURCES = main.cpp derived.cpp base.cpp
 
-CFLAGS_EXTRAS = $(LIMIT_DEBUG_INFO_FLAGS)
-
 include Makefile.rules

lldb/test/API/lang/cpp/limit-debug-info/TestWithLimitDebugInfo.py

@@ -5,13 +5,8 @@
 
 
 class TestWithLimitDebugInfo(TestBase):
-    @add_test_categories(["dwarf", "dwo"])
-    def test_limit_debug_info(self):
-        self.build()
-
-        src_file = os.path.join(self.getSourceDir(), "main.cpp")
-        src_file_spec = lldb.SBFileSpec(src_file)
-        self.assertTrue(src_file_spec.IsValid(), "breakpoint file")
+    def _run_test(self, build_dict):
+        self.build(dictionary=build_dict)
 
         # Get the path of the executable
         exe_path = self.getBuildArtifact("a.out")
@@ -21,9 +16,11 @@ def test_limit_debug_info(self):
         self.assertTrue(target.IsValid(), VALID_TARGET)
 
         # Break on main function
-        breakpoint = target.BreakpointCreateBySourceRegex("break here", src_file_spec)
-        self.assertTrue(
-            breakpoint.IsValid() and breakpoint.GetNumLocations() >= 1, VALID_BREAKPOINT
+        lldbutil.run_break_set_by_file_and_line(
+            self, "derived.h", line_number("derived.h", "// break1")
+        )
+        lldbutil.run_break_set_by_file_and_line(
+            self, "derived.h", line_number("derived.h", "// break2")
         )
 
         # Launch the process
@@ -32,14 +29,23 @@ def test_limit_debug_info(self):
 
         # Get the thread of the process
         self.assertEqual(process.GetState(), lldb.eStateStopped, PROCESS_STOPPED)
-        thread = lldbutil.get_stopped_thread(process, lldb.eStopReasonBreakpoint)
-        thread.StepInto()
 
-        # Get frame for current thread
-        frame = thread.GetSelectedFrame()
+        self.expect_expr("1", result_type="int", result_value="1")
+        self.expect_expr("this", result_type="Foo *")
+        self.expect_expr("this->x", result_type="int", result_value="12345")
+
+        self.runCmd("continue")
 
         self.expect_expr("1", result_type="int", result_value="1")
+        self.expect_expr("this", result_type="ns::Foo2 *")
+        self.expect_expr("this->x", result_type="int", result_value="23456")
 
-        v2 = frame.EvaluateExpression("this")
-        self.assertTrue(v2.IsValid(), "'expr this' results in a valid SBValue object")
-        self.assertSuccess(v2.GetError(), "'expr this' succeeds without an error.")
+    @add_test_categories(["dwarf", "dwo"])
+    def test_default(self):
+        self._run_test(dict(CFLAGS_EXTRAS="$(LIMIT_DEBUG_INFO_FLAGS)"))
+
+    @add_test_categories(["dwarf", "dwo"])
+    def test_debug_names(self):
+        self._run_test(
+            dict(CFLAGS_EXTRAS="$(LIMIT_DEBUG_INFO_FLAGS) -gdwarf-5 -gpubnames")
+        )

lldb/test/API/lang/cpp/limit-debug-info/base.cpp

@@ -1,8 +1,7 @@
 #include "base.h"
 
-FooNS::FooNS() : x(12345) {}
-
-void FooNS::bar() {
-    x = 54321;
-}
+FooBase::FooBase() : x(12345) {}
+ns::Foo2Base::Foo2Base() : x(23456) {}
 
+void FooBase::bar() {}
+void ns::Foo2Base::bar() {}

lldb/test/API/lang/cpp/limit-debug-info/base.h

@@ -1,12 +1,22 @@
-class FooNS
-{
+class FooBase {
 public:
-    virtual void bar();
-    virtual char baz() = 0;
+  virtual void bar();
 
 protected:
-    FooNS();
+  FooBase();
 
-    int x;
+  int x;
 };
 
+namespace ns {
+class Foo2Base {
+public:
+  virtual void bar();
+
+protected:
+  Foo2Base();
+
+  int x;
+};
+
+} // namespace ns

lldb/test/API/lang/cpp/limit-debug-info/derived.cpp

@@ -1,11 +1,10 @@
 #include "derived.h"
 
-Foo foo1;
-Foo foo2;
-
 Foo::Foo() { a = 12345; }
+ns::Foo2::Foo2() { a = 23456; }
 
-char Foo::baz() {
-    return (char)(x&0xff);
-}
+Foo foo1;
+Foo foo2;
 
+ns::Foo2 foo2_1;
+ns::Foo2 foo2_2;

lldb/test/API/lang/cpp/limit-debug-info/derived.h

@@ -1,19 +1,36 @@
 #include "base.h"
 
-class Foo : public FooNS
-{
+class Foo : public FooBase {
 public:
-    Foo();
+  Foo();
 
-    // Deliberately defined by hand.
-    Foo &operator=(const Foo &rhs) {
-      a = rhs.a;
-      return *this;
-    }
+  // Deliberately defined by hand.
+  Foo &operator=(const Foo &rhs) {
+    x = rhs.x; // break1
+    a = rhs.a;
+    return *this;
+  }
+  int a;
+};
+
+namespace ns {
+class Foo2 : public Foo2Base {
+public:
+  Foo2();
 
-    char baz() override;
-    int a;
+  // Deliberately defined by hand.
+  Foo2 &operator=(const Foo2 &rhs) {
+    x = rhs.x; // break2
+    a = rhs.a;
+    return *this;
+  }
+
+  int a;
 };
+} // namespace ns
 
 extern Foo foo1;
 extern Foo foo2;
+
+extern ns::Foo2 foo2_1;
+extern ns::Foo2 foo2_2;

lldb/test/API/lang/cpp/limit-debug-info/main.cpp

@@ -1,8 +1,6 @@
 #include "derived.h"
 
 int main() {
-    foo1 = foo2; // break here
-
-    foo1.bar();
-    return foo1.baz();
+  foo1 = foo2;
+  foo2_1 = foo2_2;
 }

lldb/unittests/SymbolFile/DWARF/DWARFDIETest.cpp

@@ -9,6 +9,7 @@
 #include "Plugins/SymbolFile/DWARF/DWARFDIE.h"
 #include "Plugins/SymbolFile/DWARF/DWARFDebugInfo.h"
 #include "TestingSupport/Symbol/YAMLModuleTester.h"
+#include "lldb/Core/dwarf.h"
 #include "llvm/ADT/STLExtras.h"
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
@@ -169,21 +170,20 @@ TEST(DWARFDIETest, PeekName) {
   YAMLModuleTester t(yamldata);
   auto *symbol_file =
       llvm::cast<SymbolFileDWARF>(t.GetModule()->GetSymbolFile());
-  auto &debug_info = symbol_file->DebugInfo();
+  DWARFUnit *unit = symbol_file->DebugInfo().GetUnitAtIndex(0);
 
-  DIERef first_die(std::nullopt, DIERef::Section::DebugInfo,
-                   11 /*FirstDIEOffset*/);
-  EXPECT_EQ(debug_info.PeekDIEName(first_die), "");
+  dw_offset_t first_die_offset = 11;
+  EXPECT_EQ(unit->PeekDIEName(first_die_offset), "");
 
-  DIERef second_die(std::nullopt, DIERef::Section::DebugInfo, 14);
-  EXPECT_EQ(debug_info.PeekDIEName(second_die), "NameType1");
+  dw_offset_t second_die_offset = 14;
+  EXPECT_EQ(unit->PeekDIEName(second_die_offset), "NameType1");
 
-  DIERef third_die(std::nullopt, DIERef::Section::DebugInfo, 19);
-  EXPECT_EQ(debug_info.PeekDIEName(third_die), "NameType2");
+  dw_offset_t third_die_offset = 19;
+  EXPECT_EQ(unit->PeekDIEName(third_die_offset), "NameType2");
 
-  DIERef fourth_die(std::nullopt, DIERef::Section::DebugInfo, 24);
-  EXPECT_EQ(debug_info.PeekDIEName(fourth_die), "NameType1");
+  dw_offset_t fourth_die_offset = 24;
+  EXPECT_EQ(unit->PeekDIEName(fourth_die_offset), "NameType1");
 
-  DIERef fifth_die(std::nullopt, DIERef::Section::DebugInfo, 26);
-  EXPECT_EQ(debug_info.PeekDIEName(fifth_die), "NameType2");
+  dw_offset_t fifth_die_offset = 26;
+  EXPECT_EQ(unit->PeekDIEName(fifth_die_offset), "NameType2");
 }