[Lldb-commits] [lldb] Fix debug info size statistics for split dwarf (PR #77671)

[via lldb-commits]

https://github.com/jeffreytan81 created https://github.com/llvm/llvm-project/pull/77671

`statistics dump` command relies on `SymbolFile::GetDebugInfoSize()` to get total debug info size. 
The current implementation is missing debug info for split dwarf scenarios which requires getting debug info from separate dwo/dwp files. 
This patch fixes this issue for split dwarf by parsing debug info from dwp/dwo.

>From 1bcaaf89f3508ce2809b2e194149a8395c5225ad Mon Sep 17 00:00:00 2001
From: jeffreytan81 <jeffreytan at fb.com>
Date: Wed, 10 Jan 2024 11:19:59 -0800
Subject: [PATCH] Fix debug info size statistics for split dwarf

---
 .../SymbolFile/DWARF/SymbolFileDWARF.cpp      | 23 +++++++++++++++++++
 .../SymbolFile/DWARF/SymbolFileDWARF.h        |  2 ++
 .../SymbolFile/DWARF/SymbolFileDWARFDwo.cpp   | 11 +++++++++
 .../SymbolFile/DWARF/SymbolFileDWARFDwo.h     |  2 ++
 4 files changed, 38 insertions(+)

diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
index 1a16b70f42fe1f..61e8dd5e101c88 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -2669,6 +2669,29 @@ static bool UpdateCompilerContextForSimpleTemplateNames(TypeQuery &match) {
   }
   return any_context_updated;
 }
+
+uint64_t SymbolFileDWARF::GetDebugInfoSize() {
+  DWARFDebugInfo &info = DebugInfo();
+  uint32_t num_comp_units = info.GetNumUnits();
+
+  uint64_t debug_info_size = SymbolFileCommon::GetDebugInfoSize();
+  // In dwp scenario, debug info == skeleton debug info + dwp debug info.
+  if (std::shared_ptr<SymbolFileDWARFDwo> dwp_sp = GetDwpSymbolFile())
+    return debug_info_size + dwp_sp->GetDebugInfoSize();
+
+  // In dwo scenario, debug info == skeleton debug info + all dwo debug info.
+  for (uint32_t i = 0; i < num_comp_units; i++) {
+    DWARFUnit *cu = info.GetUnitAtIndex(i);
+    if (cu == nullptr)
+      continue;
+
+    SymbolFileDWARFDwo *dwo = cu->GetDwoSymbolFile();
+    if (dwo)
+      debug_info_size += dwo->GetDebugInfoSize();
+  }
+  return debug_info_size;
+}
+
 void SymbolFileDWARF::FindTypes(const TypeQuery &query, TypeResults &results) {
 
   // Make sure we haven't already searched this SymbolFile before.
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
index 26a9502f90aa00..6d87530acf833e 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
@@ -186,6 +186,8 @@ class SymbolFileDWARF : public SymbolFileCommon {
   GetMangledNamesForFunction(const std::string &scope_qualified_name,
                              std::vector<ConstString> &mangled_names) override;
 
+  uint64_t GetDebugInfoSize() override;
+
   void FindTypes(const lldb_private::TypeQuery &match,
                  lldb_private::TypeResults &results) override;
 
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
index ca698a84a9146d..b52cb514fb1907 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
@@ -85,6 +85,17 @@ lldb::offset_t SymbolFileDWARFDwo::GetVendorDWARFOpcodeSize(
   return GetBaseSymbolFile().GetVendorDWARFOpcodeSize(data, data_offset, op);
 }
 
+uint64_t SymbolFileDWARFDwo::GetDebugInfoSize() {
+  // Directly get debug info from current dwo object file's section list
+  // instead of asking SymbolFileCommon::GetDebugInfo() which parses from
+  // owning module which is wrong.
+  SectionList *section_list =
+      m_objfile_sp->GetSectionList(/*update_module_section_list=*/false);
+  if (section_list)
+    return section_list->GetDebugInfoSize();
+  return 0;
+}
+
 bool SymbolFileDWARFDwo::ParseVendorDWARFOpcode(
     uint8_t op, const lldb_private::DataExtractor &opcodes,
     lldb::offset_t &offset, std::vector<lldb_private::Value> &stack) const {
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h
index 9f5950e51b0c18..5c4b36328cbac1 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h
@@ -47,6 +47,8 @@ class SymbolFileDWARFDwo : public SymbolFileDWARF {
                                           const lldb::offset_t data_offset,
                                           const uint8_t op) const override;
 
+  uint64_t GetDebugInfoSize() override;
+
   bool ParseVendorDWARFOpcode(uint8_t op, const DataExtractor &opcodes,
                               lldb::offset_t &offset,
                               std::vector<Value> &stack) const override;