[LLDB][Minidump] Make workaround for the Dynamic loader issue (#120166)

In #119598 my recent TLS feature seems to break crashpad symbols. I have
a few ideas on how this is happening, but for now as a mitigation I'm
checking if the Minidump was LLDB generated, and if so leveraging the
dynamic loader.

Author: Jlalond

lldb/source/Plugins/ObjectFile/Minidump/MinidumpFileBuilder.cpp

@@ -58,8 +58,8 @@ Status MinidumpFileBuilder::AddHeaderAndCalculateDirectories() {
   // First set the offset on the file, and on the bytes saved
   m_saved_data_size = HEADER_SIZE;
   // We know we will have at least Misc, SystemInfo, Modules, and ThreadList
-  // (corresponding memory list for stacks) And an additional memory list for
-  // non-stacks.
+  // (corresponding memory list for stacks), an additional memory list for
+  // non-stacks, and a stream to mark this minidump was generated by LLDB.
   lldb_private::Target &target = m_process_sp->GetTarget();
   m_expected_directories = 6;
   // Check if OS is linux and reserve directory space for all linux specific
@@ -90,7 +90,10 @@ Status MinidumpFileBuilder::AddHeaderAndCalculateDirectories() {
         "sections. Written / Expected (%" PRIx64 " / %" PRIx64 ")",
         new_offset, m_saved_data_size);
 
-  return error;
+  if (error.Fail())
+    return error;
+
+  return AddLLDBGeneratedStream();
 }
 
 Status MinidumpFileBuilder::AddDirectory(StreamType type,
@@ -126,6 +129,12 @@ Status MinidumpFileBuilder::AddDirectory(StreamType type,
   return error;
 }
 
+Status MinidumpFileBuilder::AddLLDBGeneratedStream() {
+  Status error;
+  StreamType type = StreamType::LLDBGenerated;
+  return AddDirectory(type, 0);
+}
+
 Status MinidumpFileBuilder::AddSystemInfo() {
   Status error;
   const llvm::Triple &target_triple =

lldb/source/Plugins/ObjectFile/Minidump/MinidumpFileBuilder.h

@@ -120,6 +120,7 @@ class MinidumpFileBuilder {
   void DeleteFile() noexcept;
 
 private:
+  lldb_private::Status AddLLDBGeneratedStream();
   // Add data to the end of the buffer, if the buffer exceeds the flush level,
   // trigger a flush.
   lldb_private::Status AddData(const void *data, uint64_t size);

lldb/source/Plugins/Process/minidump/MinidumpParser.cpp

@@ -49,6 +49,11 @@ llvm::ArrayRef<uint8_t> MinidumpParser::GetStream(StreamType stream_type) {
   return m_file->getRawStream(stream_type).value_or(llvm::ArrayRef<uint8_t>());
 }
 
+std::optional<llvm::ArrayRef<uint8_t>>
+MinidumpParser::GetRawStream(StreamType stream_type) {
+  return m_file->getRawStream(stream_type);
+}
+
 UUID MinidumpParser::GetModuleUUID(const minidump::Module *module) {
   auto cv_record =
       GetData().slice(module->CvRecord.RVA, module->CvRecord.DataSize);
@@ -651,6 +656,7 @@ MinidumpParser::GetStreamTypeAsString(StreamType stream_type) {
     ENUM_TO_CSTR(FacebookAbortReason);
     ENUM_TO_CSTR(FacebookThreadName);
     ENUM_TO_CSTR(FacebookLogcat);
+    ENUM_TO_CSTR(LLDBGenerated);
   }
   return "unknown stream type";
 }

lldb/source/Plugins/Process/minidump/MinidumpParser.h

@@ -59,6 +59,7 @@ class MinidumpParser {
   llvm::ArrayRef<uint8_t> GetData();
 
   llvm::ArrayRef<uint8_t> GetStream(StreamType stream_type);
+  std::optional<llvm::ArrayRef<uint8_t>> GetRawStream(StreamType stream_type);
 
   UUID GetModuleUUID(const minidump::Module *module);
 

lldb/source/Plugins/Process/minidump/ProcessMinidump.cpp

@@ -354,6 +354,22 @@ DataExtractor ProcessMinidump::GetAuxvData() {
                        GetAddressByteSize(), GetAddressByteSize());
 }
 
+bool ProcessMinidump::IsLLDBMinidump() {
+  std::optional<llvm::ArrayRef<uint8_t>> lldb_generated_section =
+      m_minidump_parser->GetRawStream(StreamType::LLDBGenerated);
+  return lldb_generated_section.has_value();
+}
+
+DynamicLoader *ProcessMinidump::GetDynamicLoader() {
+  // This is a workaround for the dynamic loader not playing nice in issue
+  // #119598. The specific reason we use the dynamic loader is to get the TLS
+  // info sections, which we can assume are not being written to the minidump
+  // unless it's an LLDB generate minidump.
+  if (IsLLDBMinidump())
+    return PostMortemProcess::GetDynamicLoader();
+  return nullptr;
+}
+
 void ProcessMinidump::BuildMemoryRegions() {
   if (m_memory_regions)
     return;

lldb/source/Plugins/Process/minidump/ProcessMinidump.h

@@ -53,6 +53,8 @@ class ProcessMinidump : public PostMortemProcess {
 
   Status DoLoadCore() override;
 
+  DynamicLoader *GetDynamicLoader() override;
+
   // Returns AUXV structure found in the core file
   lldb_private::DataExtractor GetAuxvData() override;
 
@@ -74,8 +76,8 @@ class ProcessMinidump : public PostMortemProcess {
 
   ArchSpec GetArchitecture();
 
-  Status GetMemoryRegions(
-      lldb_private::MemoryRegionInfos &region_list) override;
+  Status
+  GetMemoryRegions(lldb_private::MemoryRegionInfos &region_list) override;
 
   bool GetProcessInfo(ProcessInstanceInfo &info) override;
 
@@ -113,6 +115,7 @@ class ProcessMinidump : public PostMortemProcess {
   std::optional<MemoryRegionInfos> m_memory_regions;
 
   void BuildMemoryRegions();
+  bool IsLLDBMinidump();
 };
 
 } // namespace minidump

llvm/include/llvm/BinaryFormat/MinidumpConstants.def

@@ -85,6 +85,10 @@ HANDLE_MDMP_STREAM_TYPE(0xFACECCCC, FacebookAppStateLog)
 HANDLE_MDMP_STREAM_TYPE(0xFACEDEAD, FacebookAbortReason)
 HANDLE_MDMP_STREAM_TYPE(0xFACEE000, FacebookThreadName)
 
+// LLDB specific stream types
+// Ascii for 'LLDB'
+HANDLE_MDMP_STREAM_TYPE(0x4C4C4442, LLDBGenerated)
+
 HANDLE_MDMP_ARCH(0x0000, X86)       // PROCESSOR_ARCHITECTURE_INTEL
 HANDLE_MDMP_ARCH(0x0001, MIPS)      // PROCESSOR_ARCHITECTURE_MIPS
 HANDLE_MDMP_ARCH(0x0002, Alpha)     // PROCESSOR_ARCHITECTURE_ALPHA