1 files changed, 83 insertions, 8 deletions

diff --git a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
index e507f0e4d74..64e32e5aa41 100644
--- a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
+++ b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
@@ -18,6 +18,7 @@
 #include "lldb/Core/PluginManager.h"
 #include "lldb/Core/Section.h"
 #include "lldb/Host/FileSystem.h"
+#include "lldb/Host/LZMA.h"
 #include "lldb/Symbol/DWARFCallFrameInfo.h"
 #include "lldb/Symbol/SymbolContext.h"
 #include "lldb/Target/SectionLoadList.h"
@@ -1842,6 +1843,70 @@ void ObjectFileELF::CreateSections(SectionList &unified_section_list) {
   // unified section list.
   if (GetType() != eTypeDebugInfo)
     unified_section_list = *m_sections_up;
+  
+  // If there's a .gnu_debugdata section, we'll try to read the .symtab that's
+  // embedded in there and replace the one in the original object file (if any).
+  // If there's none in the orignal object file, we add it to it.
+  if (auto gdd_obj_file = GetGnuDebugDataObjectFile()) {
+    if (auto gdd_objfile_section_list = gdd_obj_file->GetSectionList()) {
+      if (SectionSP symtab_section_sp =
+              gdd_objfile_section_list->FindSectionByType(
+                  eSectionTypeELFSymbolTable, true)) {
+        SectionSP module_section_sp = unified_section_list.FindSectionByType(
+            eSectionTypeELFSymbolTable, true);
+        if (module_section_sp)
+          unified_section_list.ReplaceSection(module_section_sp->GetID(),
+                                              symtab_section_sp);
+        else
+          unified_section_list.AddSection(symtab_section_sp);
+      }
+    }
+  }  
+}
+
+std::shared_ptr<ObjectFileELF> ObjectFileELF::GetGnuDebugDataObjectFile() {
+  if (m_gnu_debug_data_object_file != nullptr)
+    return m_gnu_debug_data_object_file;
+
+  SectionSP section =
+      GetSectionList()->FindSectionByName(ConstString(".gnu_debugdata"));
+  if (!section)
+    return nullptr;
+
+  if (!lldb_private::lzma::isAvailable()) {
+    GetModule()->ReportWarning(
+        "No LZMA support found for reading .gnu_debugdata section");
+    return nullptr;
+  }
+
+  // Uncompress the data
+  DataExtractor data;
+  section->GetSectionData(data);
+  llvm::SmallVector<uint8_t, 0> uncompressedData;
+  auto err = lldb_private::lzma::uncompress(data.GetData(), uncompressedData);
+  if (err) {
+    GetModule()->ReportWarning(
+        "An error occurred while decompression the section %s: %s",
+        section->GetName().AsCString(), llvm::toString(std::move(err)).c_str());
+    return nullptr;
+  }
+
+  // Construct ObjectFileELF object from decompressed buffer
+  DataBufferSP gdd_data_buf(
+      new DataBufferHeap(uncompressedData.data(), uncompressedData.size()));
+  auto fspec = GetFileSpec().CopyByAppendingPathComponent(
+      llvm::StringRef("gnu_debugdata"));
+  m_gnu_debug_data_object_file.reset(new ObjectFileELF(
+      GetModule(), gdd_data_buf, 0, &fspec, 0, gdd_data_buf->GetByteSize()));
+
+  // This line is essential; otherwise a breakpoint can be set but not hit.
+  m_gnu_debug_data_object_file->SetType(ObjectFile::eTypeDebugInfo);
+
+  ArchSpec spec = m_gnu_debug_data_object_file->GetArchitecture();
+  if (spec && m_gnu_debug_data_object_file->SetModulesArchitecture(spec))
+    return m_gnu_debug_data_object_file;
+  
+  return nullptr;
 }
 
 // Find the arm/aarch64 mapping symbol character in the given symbol name.
@@ -2649,19 +2714,29 @@ Symtab *ObjectFileELF::GetSymtab() {
     // while the reverse is not necessarily true.
     Section *symtab =
         section_list->FindSectionByType(eSectionTypeELFSymbolTable, true).get();
-    if (!symtab) {
-      // The symtab section is non-allocable and can be stripped, so if it
-      // doesn't exist then use the dynsym section which should always be
-      // there.
-      symtab =
-          section_list->FindSectionByType(eSectionTypeELFDynamicSymbols, true)
-              .get();
-    }
     if (symtab) {
       m_symtab_up.reset(new Symtab(symtab->GetObjectFile()));
       symbol_id += ParseSymbolTable(m_symtab_up.get(), symbol_id, symtab);
     }
 
+    // The symtab section is non-allocable and can be stripped, while the
+    // .dynsym section which should always be always be there. To support the
+    // minidebuginfo case we parse .dynsym when there's a .gnu_debuginfo
+    // section, nomatter if .symtab was already parsed or not. This is because
+    // minidebuginfo normally removes the .symtab symbols which have their
+    // matching .dynsym counterparts.
+    if (!symtab ||
+        GetSectionList()->FindSectionByName(ConstString(".gnu_debugdata"))) {
+      Section *dynsym =
+          section_list->FindSectionByType(eSectionTypeELFDynamicSymbols, true)
+              .get();
+      if (dynsym) {
+        if (!m_symtab_up)
+          m_symtab_up.reset(new Symtab(dynsym->GetObjectFile()));
+        symbol_id += ParseSymbolTable(m_symtab_up.get(), symbol_id, dynsym);
+      }
+    }
+
     // DT_JMPREL
     //      If present, this entry's d_ptr member holds the address of
     //      relocation