WIP: Add minidump save-core functionality to ELF object files

[Aj0SK]

Summary

This change adds save-core functionality into the ObjectFileELF that enables
saving minidump of a stopped process. This change is mainly targeting Linux
running on x86_64 machines. Minidump should contain basic information needed
to examine state of threads, local variables and stack traces. Full support
for other platforms is not so far implemented. API tests are using LLDB's
MinidumpParser.

[clayborg]

I like the idea of this! I have a minidump creation tool I wrote in python for making tests.

ELF files support core files in their native file format, so I think the ObjectFileELF::SaveCore(...) should actually save an ELF core file if it saves anything. So we should move the minidump creation to another location. I mention ideas below.

When running "process save-core" we can add a new option like "--plugin=<name>", and if this option is specified we will look for a plug-in name that matches when iterating over the instances that support core file exporting. Right now the save core calls the plugin manager:

Status PluginManager::SaveCore(const lldb::ProcessSP &process_sp,
                               const FileSpec &outfile,
                               lldb::SaveCoreStyle &core_style) {
  Status error;
  auto &instances = GetObjectFileInstances().GetInstances();
  for (auto &instance : instances) {
    if (instance.save_core &&
        instance.save_core(process_sp, outfile, core_style, error))
      return error;
  }
  error.SetErrorString(
      "no ObjectFile plugins were able to save a core for this process");
  return error;
}

Currently we are expecting only one ObjectFile class to return true for any given process. But since ObjectFileELF::SaveCore(...) could eventually be added to ObjectFileELF, we need a way to force a plug-in to be considered. If we add an extra "ConstString plugin_name" to the arguments, we can check the name and target a different plug-in. It should be possible to save a core file in different formats.

So I propose:

• remove code from ELF ObjectFile plug-in
• modify PluginManager::SaveCore(...) to take an extra "ConstString plugin_name" parameter.
  • If this parameter is valid, skip any "instance" whose name doesn't match
• Modify the ObjectFileSaveCore callback definition to take a "bool force" parameter which will make the plug-ins skip the triple detection stuff that will skip saving the core file if each SaveCore(...) function didn't like the triple it was passed. It is fine for a plug-in to return an error stating that saving a core file with the current process doesn't make sense since each core file has to have support for saving registers.
• make a new Minidump ObjectFile plug-in at "lldb/source/Plugins/ObjectFile/Minidump"
  • Create a lldb/source/Plugins/ObjectFile/Minidump/ObjectFileMinidump.cpp and lldb/source/Plugins/ObjectFile/Minidump/ObjectFileMinidump.h
  • when you register the callbacks for this plug-in, only register the ObjectFileMinidump::SaveCore callback (see example code below)

void ObjectFileMinidump::Initialize() {
  PluginManager::RegisterPlugin(
      GetPluginNameStatic(),
      GetPluginDescriptionStatic(), 
      /*create_callback=*/nullptr,
      /*create_memory_callback=*/nullptr, 
      /*get_module_specifications=*/nullptr,
      SaveCore);
}

Then hopefully you can just make a very ObjectFileMinidump with a few plug-in template functions and the SaveCore(...) function. Let me know if any of this is not clear.

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

70 ↗

(On Diff #366982)

Seems like we should return an error here if the architecture isn't supported with a nice error string that gets displayed. We shouldn't default to AMD64 right?

80 ↗

(On Diff #366982)

We should be able to populate this correctly using the triple right? And error out if we don't support the OS?

lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

725–727 ↗

(On Diff #366982)

remove braces for single statement if (LLVM coding guidelines)

730–732 ↗

(On Diff #366982)

remove braces for single statement if (LLVM coding guidelines)

738–740 ↗

(On Diff #366982)

remove braces for single statement if (LLVM coding guidelines)

743–745 ↗

(On Diff #366982)

remove braces for single statement if (LLVM coding guidelines)

748–750 ↗

(On Diff #366982)

remove braces for single statement if (LLVM coding guidelines)

762–764 ↗

(On Diff #366982)

remove braces for single statement if (LLVM coding guidelines)

[clayborg]

lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

751 ↗

(On Diff #366982)

The minidump parser in LLDB supports many linux specific streams (see llvm/include/llvm/BinaryFormat/MinidumpConstants.def):

HANDLE_MDMP_STREAM_TYPE(0x47670003, LinuxCPUInfo)    // /proc/cpuinfo
HANDLE_MDMP_STREAM_TYPE(0x47670004, LinuxProcStatus) // /proc/$x/status
HANDLE_MDMP_STREAM_TYPE(0x47670005, LinuxLSBRelease) // /etc/lsb-release
HANDLE_MDMP_STREAM_TYPE(0x47670006, LinuxCMDLine)    // /proc/$x/cmdline
HANDLE_MDMP_STREAM_TYPE(0x47670007, LinuxEnviron)    // /proc/$x/environ
HANDLE_MDMP_STREAM_TYPE(0x47670008, LinuxAuxv)       // /proc/$x/auxv
HANDLE_MDMP_STREAM_TYPE(0x47670009, LinuxMaps)       // /proc/$x/maps
HANDLE_MDMP_STREAM_TYPE(0x4767000A, LinuxDSODebug)
HANDLE_MDMP_STREAM_TYPE(0x4767000B, LinuxProcStat)   // /proc/$x/stat
HANDLE_MDMP_STREAM_TYPE(0x4767000C, LinuxProcUptime) // uptime
HANDLE_MDMP_STREAM_TYPE(0x4767000D, LinuxProcFD)     // /proc/$x/fd

Many of these could easily be added to the file as they are just a copy of these files from disk.

[Aj0SK]

Move minidump save-core functionality to separate plugin

[clayborg]

Thanks for moving over into object file. See inlined comments, we should be able to get this down to just the SaveCore and other static functions that just return nothing. Let me know if the inlined comments don't make sense.

lldb/source/Commands/CommandObjectProcess.cpp

1235

Make this a ConstString

1242

Remove this if we switch m_requested_plugin_name to be a ConstString. Also a quick FYI: ConstString has a std::string constructor, so there is no need to add ".c_str()" here if this code was going to stay.

1243

We haven't changed the number of arguments here right? Options and their option values to no count towards the argument count. So all of these have just one argument:

(lldb) process save-core <file>
(lldb) process save-core -p <plugin> <file>
(lldb) proicess save-core -s <style> <file>
(lldb) process save-core -p <plugin> -s <style> <file>

The one argument is <file>

1247

lldb/source/Commands/Options.td

753

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

31–32

We have two options here:
1 - if we want to pass NULL for any callbacks, then we need to fix all callsites to that use PluginManager::GetObjectFileCreateMemoryCallbackAtIndex(...) and PluginManager::GetObjectFileGetModuleSpecificationsCallbackAtIndex(...) to have this done inside of new plug-in manager PluginManager::CreateMemoryCallbackAtIndex(...) and PluginManager::GetModuleSpecifications(...) where these new functions iterate over all plug-ins and skip any plug-ins that have NULL callbacks.
2 - add valid create_memory_callback and get_module_specifications callbacks that return invalid values

Otherwise this plug-in might stop the iteration early for existing callers of PluginManager::GetObjectFileCreateMemoryCallbackAtIndex(...) and PluginManager::GetObjectFileGetModuleSpecificationsCallbackAtIndex(...).

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

16

Since minidump files are not object files, you can just inherit from lldb_private::PluginInterface. Then you don't need to override any pure virtual functions from lldb_private::ObjectFile. We should add a comment before this class stating something like:

///  ObjectFileMinidump is created only to be able to save minidump core files from existing processes with the ObjectFileMinidump::SaveCore function. Minidump files are not ObjectFile objects, but they are core files and currently LLDB's ObjectFile plug-ins handle emitting core files. If the core file saving ever moves into a new plug-in type within LLDB, this code should move as well, but for now this is where this belongs architecturally.

39–44

If we don't inherit from lldb_private::ObjectFile, the we don't need the LLVM RTTI stuff either.

46–82

You can remove all "override" functions if you don't inherit from lldb_private::ObjectFile and inherit only from PluginInterface.

91–92

Remove

94–97

Remove, since minidump files are not object files.

[Aj0SK]

Thanks for the review! Some requested changes need to be clarified for me. I have a problem mainly with successfully registering the Plugin when it inherits only from PluginInterface.

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

31–32

I would prefer modifying code outside of this functionality as little as possible so I would stick to the second option. However, maybe returning the invalid values is also not the best solution. Also, does this option works with ObjectFileMinidump inheriting from PluginInterface? I think that I am unable to use the same PluginManager::RegisterPlugin method, so not sure how this plugin gets to ObjectFilesInstances... Maybe I am missing out something.

[clayborg]

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

32

It should be fine to not inherit from ObjectFile and yes I agree, probably best to not modify other code.

All you need to provide is static function callbacks that have the correct static function signature, and that doesn't require your class to inherit from ObjectFile. You already have a CreateInstance function to see how to do this. The CreateInstance(...) function you have can do nothing and just return nullptr.

Then you need to make a create memory callback and a get module specifications:

ObjectFile *ObjectFileMinidump::CreateMemoryInstance(
    const lldb::ModuleSP &module_sp, DataBufferSP &data_sp,
    const ProcessSP &process_sp, lldb::addr_t header_addr) {
  return nullptr;
}

size_t ObjectFileMinidump::GetModuleSpecifications(
    const lldb_private::FileSpec &file, lldb::DataBufferSP &data_sp,
    lldb::offset_t data_offset, lldb::offset_t file_offset,
    lldb::offset_t length, lldb_private::ModuleSpecList &specs) {
  specs.Clear();
  return 0;
}

Then your registration call looks like:

PluginManager::RegisterPlugin(
  GetPluginNameStatic(), GetPluginDescriptionStatic(), CreateInstance,
      CreateMemoryInstance, GetModuleSpecifications, SaveCore);

[Aj0SK]

Change ObjectFileMinidump plugin to inherit from PluginInterface

[clayborg]

Very nice! Structure is good now. I found a few other issue we should fix as well.

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

226

I am not sure if the object file's full size is the right value here. I think the right value would be the last contiguous loaded address range for a given file. This information is going to be used to set the load addresses of any sections in the object file when it is loaded, and if we have a huge ELF file that has tons of debug info, this is going to make the loaded address range way too big.

So the algorithm I would suggest is:
1 - grab the section that contains base address:
2 - in a loop, grab the next section that starts at the end of this section, and as long as the addresses are contiguous, increase the SizeOfImage:

So something like:

lldb::SectionSP sect_sp = mod->GetObjectFile()->GetBaseAddress().GetSection();
uint64_t SizeOfImage = 0;
if (sect_sp) {
  lldb::addr_t sect_addr = sect_sp->GetLoadAddress(&target);
  // Use memory size since zero fill sections, like ".bss", will be smaller on disk.
  lldb::addr_t sect_size = sect_sp->MemorySize(); 
  // This will usually be zero, but make sure to calculate the BaseOfImage offset.
  const lldb::addr_t base_sect_offset = m.BaseOfImage - sect_addr;
  SizeOfImage = sect_size - base_sect_offset;
  lldb::addr_t next_sect_addr = sect_addr + sect_size;
  Address sect_so_addr;
  target.ResolveLoadAddress(next_sect_addr, sect_so_addr);
  lldb::SectionSP next_sect_sp = sect_so_addr.GetSections();
  while (next_sect_sp && next_sect_sp->GetLoadBaseAddress(&target) == next_sect_addr)) {
    sect_size = sect_sp->MemorySize(); 
    SizeOfImage += sect_size;
    next_sect_addr += sect_size;
    target.ResolveLoadAddress(next_sect_addr, sect_so_addr);
    next_sect_sp = sect_so_addr.GetSections();
  }
  m.SizeOfImage = static_cast<llvm::support::ulittle32_t>(SizeOfImage);
} else {
  m.SizeOfImage = static_cast<llvm::support::ulittle32_t>(sect_size);
}

520

This should take in the CoreStyle and only emit what was asked for.

If style is set to "eSaveCoreStackOnly", then grab only the memory regions for each thread stack pointer and save only those.

We can't tell from LLDB APIs if a page is dirty, so if we get "eSaveCoreDirtyOnly", then we will need to save all memory regions that have write permissions.

If it is either "eSaveCoreFull" or "eSaveCoreUnspecified" then save everything.

668

Do we need to make sure size is not zero?

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

2–4

Fix this header comment line to be on one line.

[Aj0SK]

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

226

Thank you for the suggestion. I will add it to the next revision.

520

I agree that this code should take care of a CoreStyle but it poses a significant problem to this implementation as it was mainly designed to save smaller Minidumps. This solution stores all of the information in memory before dumping them (this eases an implementation quite a bit because of the way how Minidump pointers (offsets) are working). This implementation, on my machine, exhausted memory before the minidump could be written in case of a full memory dump. At this time, we don't plan to reimplement this solution in the way it would allow to store all the data on disc at the time of minidump creation so there are two possible solutions that I see:

1. If the type of the CoreStyle is full or dirty, this plugin will return false from the SaveCore function. Then maybe the default CoreStyle for this plugin should be changed to "eSaveCoreStackOnly".

2. To the best of my knowledge, it should be theoretically possible to reimplement Dump() method to sort of take special care of a MemoryListStream, dumping also the memory information at the end of the minidump file as I think the memory dump is the most stressful for the memory and otherwise there is no problem with this.

668

I can add this. The idea was that even if the file is "empty", we at least give the user opening the minidump the information that we have been able to find this file and add it to the minidump instead of only not providing any information at all.

[Aj0SK]

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

520

To state my preference, I would rather stick to the first option and landed a minimum viable product. The only reason for this is that I have this version way better tested and also I am not entirely sure about how minidump deals with the whole memory dumps as it can be a little problematic for a big memory chunks... Then, I would rather add the necessary changes in the next patch...

[clayborg]

No worries on only saving out the minimal for now, but just make sure that you error out if CoreStyle is anything but "eSaveCoreUnspecified" or "eSaveCoreStackOnly".

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

520

That is fine. I was just looking at the implementation below and I think I might know why this was taking up too much space. I will comment below, and maybe this will fix the issues of storing way too much info in the miniump

523

FYI: memory region for address zero often has no permissions, so there is no need to actually try and save this memory. For any memory region be sure the check if it has permissions using:

if (region_info.GetLLDBPermissions() != 0)

before trying to read or save this off. I will comment below

531

Should we have a std::set<lldb::addr_t> to store the base of any regions that have already been saved? Many PC values could be in the same regions (like when many threads are waiting in syscalls).

545–547

Why are we checking the region_info for address zero here? The first time through this loop, it will contain information for address zero which will be a region that has no permissions. I suggest a new main loop in the comment below which simplifies this entire logic and also makes sure we don't emit the same region more than once.

550

Shouldn't this be the main loop that would replace the "while (range_info.GetRange().GetRangeBase() != LLDB_INVALID_ADDRESS)" loop? I would think that the main loop wiould be something like:

std::set<addr_t> visited_region_base_addresses;
for (size_t interesting_address : interesting_addresses) {
  error = process_sp->GetMemoryRegionInfo(interesting_address, range_info);
  // Skip failed memory region requests or any regions with no permissions.
  if (error.Fail() || range_info.GetPermissions() == 0)
    continue;
  const addr_t addr = range_info.GetRange().GetRangeBase();
  // Skip any regions we have already saved out.
  if (visited_region_base_addresses.insert(addr).second == false)
    continue;
  const addr_t size = range_info.GetRange().GetByteSize();
  if (size == 0)
    continue;
  auto data_up = std::make_unique<DataBufferHeap>(size, 0);
  const size_t bytes_read = process_sp->ReadMemory(addr, data_up->GetBytes(), size, error);
  if (bytes_read == 0)
    continue;
  // We have a good memory region with valid bytes to store.
  LocationDescriptor memory_dump;
  memory_dump.DataSize = static_cast<llvm::support::ulittle32_t>(size);
  memory_dump.RVA =static_cast<llvm::support::ulittle32_t>(GetCurrentDataEndOffset());
  MemoryDescriptor memory_desc;
  memory_desc.StartOfMemoryRange = static_cast<llvm::support::ulittle64_t>(addr);
  memory_desc.Memory = memory_dump;
  mem_descriptors.push_back(memory_desc);
  m_data.AppendData(data_up->GetBytes(), bytes_read);
}

552

Make sure the memory region has any permissions. This returns a logic OR bitmask of lldb::Permissions bits:

enum Permissions {
  ePermissionsWritable = (1u << 0),
  ePermissionsReadable = (1u << 1),
  ePermissionsExecutable = (1u << 2)};
};

No permissions will return 0;

569

You should listen to the return value from this ReadMemory call and only write this many bytes to the memory region. See my above proposed full loop source code abiove, as it reads the memory first before creating the LocationDescriptor and MemoryDescriptor and it skips to the next address in the loop if things go bad during memory read. It also stores the number if bytes that were actually read in case the process memory read comes back with fewer or no bytes.

[Aj0SK]

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

550

This kind of an approach was something I also thought about and in fact, I was mainly inspired by this approach. Also, the previous comment about the need of saving the loaded modules addresses in a set doesn't apply to my solution, am I correct? Just to clear it a little bit, I like your solution though and it's better when I think about it. Thanks for the suggestion!

[Aj0SK]

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

520

In fact, we are mostly interested in the client-server setup where every spared MB counts. In case it would be also benefiting for LLDB, I can also come up with an implementation that doesn't save full 8MB per stack but also limits this... Most of the solutions, that were used for implementing this functionality(breakpad, crashpad) limit stack information etc. breakpad.

523

Thanks, good to know.

531

In the proposed approach, I believe so. In the old approach this was taken care of by the fact that we only went through the every segment only once.

550

One thing, that could be a little problematic with the new approach is, if the possibility to save full/dirty pages dump would be requested... In this case, we still need to go through all of the sections...

569

Also done this on other places where I use ReadMemory...

[Aj0SK]

Add error for dump core style other than stack and change procedure getting the memory list stream.

[clayborg]

Thanks for all of the changes! Looks great.

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

550

Correct, we would just iterate over all memory regions and get the next region by asking for the region that starts at the end address of the current region.

[Aj0SK]

Fixes arm and aarch64 build run fails. Adding aarch64 to the matching in SystemInfo stream and activating test only on x86_64 as this is the only platform where also thread info etc. is being saved.

[Aj0SK]

Fix not-correctly applied change from review regarding memory reading.

[clayborg]

lldb/test/API/functionalities/process_save_core_minidump/TestProcessSaveCoreMinidump.py

18

Do we only support x86_64 right now? If we are actually supporting other architectures and emitting a minidump for them, we should be testing them. Do we return an error for any architectures that we don't support in the ObjectFIleMinidump::SaveCore(...) function?

[Aj0SK]

lldb/test/API/functionalities/process_save_core_minidump/TestProcessSaveCoreMinidump.py

18

We only support "full-featured" minidump for the x86_64. For some platforms, listed in AddSystemInfo method we provide minidump with only basic information(SystemInfo, ModuleInfo and MiscInfo streams). For all other platforms, no minidump is created and it will error-out...

[MaskRay]

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

120

https://llvm.org/docs/CodingStandards.html#error-and-warning-messages

Don't capitalize messages and don't append .

732

The format specifiers are wrong. size_t should use %zd and one uint64_t below should use PRIu64.

I have fixed them.

lldb/include/lldb/Core/PluginManager.h

public:
   static ObjectFileGetModuleSpecifications
   GetObjectFileGetModuleSpecificationsCallbackAtIndex(uint32_t idx);
 
   static ObjectFileCreateMemoryInstance
   GetObjectFileCreateMemoryCallbackForPluginName(ConstString name);
 
   static Status SaveCore(const lldb::ProcessSP &process_sp,
                          const FileSpec &outfile,
-                         lldb::SaveCoreStyle &core_style);
+                         lldb::SaveCoreStyle &core_style,
+                         const ConstString plugin_name);
 
   // ObjectContainer
   static bool
   RegisterPlugin(ConstString name, const char *description,
                  ObjectContainerCreateInstance create_callback,
                  ObjectFileGetModuleSpecifications get_module_specifications);
 
   static bool UnregisterPlugin(ObjectContainerCreateInstance create_callback);

lldb/source/API/SBProcess.cpp

lldb::SBError SBProcess::SaveCore(const char *file_name) {
 
   if (process_sp->GetState() != eStateStopped) {
     error.SetErrorString("the process is not stopped");
     return LLDB_RECORD_RESULT(error);
   }
 
   FileSpec core_file(file_name);
   SaveCoreStyle core_style = SaveCoreStyle::eSaveCoreFull;
-  error.ref() = PluginManager::SaveCore(process_sp, core_file, core_style);
+  error.ref() =
+      PluginManager::SaveCore(process_sp, core_file, core_style, ConstString());
   return LLDB_RECORD_RESULT(error);
 }
 
 lldb::SBError
 SBProcess::GetMemoryRegionInfo(lldb::addr_t load_addr,
                                SBMemoryRegionInfo &sb_region_info) {
   LLDB_RECORD_METHOD(lldb::SBError, SBProcess, GetMemoryRegionInfo,
                      (lldb::addr_t, lldb::SBMemoryRegionInfo &), load_addr,

lldb/source/Commands/CommandObjectProcess.cpp

 }
 
 #define LLDB_OPTIONS_process_save_core
 #include "CommandOptions.inc"
 
 class CommandObjectProcessSaveCore : public CommandObjectParsed {
 public:
   CommandObjectProcessSaveCore(CommandInterpreter &interpreter)
-      : CommandObjectParsed(interpreter, "process save-core",
-                            "Save the current process as a core file using an "
-                            "appropriate file type.",
-                            "process save-core [-s corefile-style] FILE",
-                            eCommandRequiresProcess | eCommandTryTargetAPILock |
-                                eCommandProcessMustBeLaunched) {}
+      : CommandObjectParsed(
+            interpreter, "process save-core",
+            "process save-core [-s corefile-style -p plugin-name] FILE",
 
   ~CommandObjectProcessSaveCore() override = default;
 
   Options *GetOptions() override { return &m_options; }
 
   class CommandOptions : public Options {
   public:
     CommandOptions()
         : Options(), m_requested_save_core_style(eSaveCoreUnspecified) {}
 
     ~CommandOptions() override = default;
 
     llvm::ArrayRef<OptionDefinition> GetDefinitions() override {
       return llvm::makeArrayRef(g_process_save_core_options);
     }
 
     Status SetOptionValue(uint32_t option_idx, llvm::StringRef option_arg,
                           ExecutionContext *execution_context) override {
       const int short_option = m_getopt_table[option_idx].val;
       Status error;
 
       switch (short_option) {
+      case 'p':
+        m_requested_plugin_name.SetString(option_arg);
+        break;
       case 's':
         m_requested_save_core_style =
             (lldb::SaveCoreStyle)OptionArgParser::ToOptionEnum(
                 option_arg, GetDefinitions()[option_idx].enum_values,
                 eSaveCoreUnspecified, error);
         break;
       default:
         llvm_unreachable("Unimplemented option");
       }
 
       return {};
     }
 
     void OptionParsingStarting(ExecutionContext *execution_context) override {
       m_requested_save_core_style = eSaveCoreUnspecified;
+      m_requested_plugin_name.Clear();
     }
 
     // Instance variables to hold the values for command options.
     SaveCoreStyle m_requested_save_core_style;
+    ConstString m_requested_plugin_name;
   };
 
 protected:
   bool DoExecute(Args &command, CommandReturnObject &result) override {
     ProcessSP process_sp = m_exe_ctx.GetProcessSP();
     if (process_sp) {
       if (command.GetArgumentCount() == 1) {
         FileSpec output_file(command.GetArgumentAtIndex(0));
         SaveCoreStyle corefile_style = m_options.m_requested_save_core_style;
         Status error =
-            PluginManager::SaveCore(process_sp, output_file, corefile_style);
+            PluginManager::SaveCore(process_sp, output_file, corefile_style,
+                                    m_options.m_requested_plugin_name);
         if (error.Success()) {
           if (corefile_style == SaveCoreStyle::eSaveCoreDirtyOnly ||
               corefile_style == SaveCoreStyle::eSaveCoreStackOnly) {
             result.AppendMessageWithFormat(
                 "\nModified-memory or stack-memory only corefile "
                 "created.  This corefile may \n"
                 "not show library/framework/app binaries "
                 "on a different system, or when \n"

lldb/source/Commands/Options.td

let Command = "process status" in {
   def process_status_verbose : Option<"verbose", "v">, Group<1>,
     Desc<"Show verbose process status including extended crash information.">;
 }
 
 let Command = "process save_core" in {
   def process_save_core_style : Option<"style", "s">, Group<1>,
     EnumArg<"SaveCoreStyle", "SaveCoreStyles()">, Desc<"Request a specific style "
     "of corefile to be saved.">;
+  def process_save_core_plugin_name : Option<"plugin-name", "p">,
+    OptionalArg<"Plugin">, Desc<"Specify a plugin name to create the core file."
+    "This allows core files to be saved in different formats.">;
 }
 
 let Command = "process trace save" in {
   def process_trace_save_directory: Option<"directory", "d">,
     Group<1>,
     Arg<"Value">, Required,
     Desc<"The directory where the trace will be saved."
         "It will be created if it does not exist.">;

lldb/source/Core/PluginManager.cpp

for (auto &instance : instances) {
     if (instance.name == name)
       return instance.create_memory_callback;
   }
   return nullptr;
 }
 
 Status PluginManager::SaveCore(const lldb::ProcessSP &process_sp,
                                const FileSpec &outfile,
-                               lldb::SaveCoreStyle &core_style) {
+                               lldb::SaveCoreStyle &core_style,
+                               const ConstString plugin_name) {
   Status error;
   auto &instances = GetObjectFileInstances().GetInstances();
   for (auto &instance : instances) {
+    if (plugin_name && instance.name != plugin_name)
+      continue;
     if (instance.save_core &&
         instance.save_core(process_sp, outfile, core_style, error))
       return error;
   }
   error.SetErrorString(
       "no ObjectFile plugins were able to save a core for this process");
   return error;
 }

lldb/source/Plugins/ObjectFile/CMakeLists.txt

 add_subdirectory(Breakpad)
 add_subdirectory(ELF)
 add_subdirectory(Mach-O)
+add_subdirectory(Minidump)
 add_subdirectory(PDB)
 add_subdirectory(PECOFF)
 add_subdirectory(JIT)
 add_subdirectory(wasm)

lldb/source/Plugins/ObjectFile/Minidump/CMakeLists.txt

+add_lldb_library(lldbPluginObjectFileMinidump PLUGIN
+  ObjectFileMinidump.cpp
+  MinidumpFileBuilder.cpp
+
+  LINK_LIBS
+    lldbCore
+    lldbHost
+    lldbSymbol
+    lldbTarget
+    lldbUtility
+    lldbPluginProcessUtility
+  LINK_COMPONENTS
+    Support
+  )

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

+//===-- MinidumpFileBuilder.h ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+/// \file
+/// Structure holding data neccessary for minidump file creation.
+///
+/// The class MinidumpFileWriter is used to hold the data that will eventually
+/// be dumped to the file.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_SOURCE_PLUGINS_OBJECTFILE_MINIDUMP_MINIDUMPFILEBUILDER_H
+#define LLDB_SOURCE_PLUGINS_OBJECTFILE_MINIDUMP_MINIDUMPFILEBUILDER_H
+
+#include <cstddef>
+
+#include "lldb/Target/Target.h"
+#include "lldb/Utility/DataBufferHeap.h"
+#include "lldb/Utility/Status.h"
+
+#include "llvm/Object/Minidump.h"
+
+// Write std::string to minidump in the UTF16 format(with null termination char)
+// with the size(without null termination char) preceding the UTF16 string.
+// Empty strings are also printed with zero length and just null termination
+// char.
+lldb_private::Status WriteString(const std::string &to_write,
+                                 lldb_private::DataBufferHeap *buffer);
+
+/// \class MinidumpFileBuilder
+/// Minidump writer for Linux
+///
+/// This class provides a Minidump writer that is able to
+/// snapshot the current process state. For the whole time, it stores all
+/// the data on heap.
+class MinidumpFileBuilder {
+public:
+  MinidumpFileBuilder() = default;
+
+  MinidumpFileBuilder(const MinidumpFileBuilder &) = delete;
+  MinidumpFileBuilder &operator=(const MinidumpFileBuilder &) = delete;
+
+  MinidumpFileBuilder(MinidumpFileBuilder &&other) = default;
+  MinidumpFileBuilder &operator=(MinidumpFileBuilder &&other) = default;
+
+  ~MinidumpFileBuilder() = default;
+
+  // Add SystemInfo stream, used for storing the most basic information
+  // about the system, platform etc...
+  lldb_private::Status AddSystemInfo(const llvm::Triple &target_triple);
+  // Add ModuleList stream, containing information about all loaded modules
+  // at the time of saving minidump.
+  lldb_private::Status AddModuleList(lldb_private::Target &target);
+  // Add ThreadList stream, containing information about all threads running
+  // at the moment of core saving. Contains information about thread
+  // contexts.
+  lldb_private::Status AddThreadList(const lldb::ProcessSP &process_sp);
+  // Add Exception stream, this contains information about the exception
+  // that stopped the process. In case no thread made exception it return
+  // failed status.
+  lldb_private::Status AddException(const lldb::ProcessSP &process_sp);
+  // Add MemoryList stream, containing dumps of important memory segments
+  lldb_private::Status AddMemoryList(const lldb::ProcessSP &process_sp);
+  // Add MiscInfo stream, mainly providing ProcessId
+  void AddMiscInfo(const lldb::ProcessSP &process_sp);
+  // Add informative files about a Linux process
+  void AddLinuxFileStreams(const lldb::ProcessSP &process_sp);
+  // Dump the prepared data into file. In case of the failure data are
+  // intact.
+  lldb_private::Status Dump(lldb::FileUP &core_file) const;
+  // Returns the current number of directories(streams) that have been so far
+  // created. This number of directories will be dumped when calling Dump()
+  size_t GetDirectoriesNum() const;
+
+private:
+  // Add directory of StreamType pointing to the current end of the prepared
+  // file with the specified size.
+  void AddDirectory(llvm::minidump::StreamType type, size_t stream_size);
+  size_t GetCurrentDataEndOffset() const;
+
+  // Stores directories to later put them at the end of minidump file
+  std::vector<llvm::minidump::Directory> m_directories;
+  // Main data buffer consisting of data without the minidump header and
+  // directories
+  lldb_private::DataBufferHeap m_data;
+};
+
+#endif // LLDB_SOURCE_PLUGINS_OBJECTFILE_MINIDUMP_MINIDUMPFILEBUILDER_H
 No newline at end of file

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

+//===-- MinidumpFileBuilder.cpp -------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "MinidumpFileBuilder.h"
+
+#include "Plugins/Process/minidump/RegisterContextMinidump_x86_64.h"
+
+#include "lldb/Core/Module.h"
+#include "lldb/Core/ModuleList.h"
+#include "lldb/Core/Section.h"
+#include "lldb/Target/MemoryRegionInfo.h"
+#include "lldb/Target/Process.h"
+#include "lldb/Target/RegisterContext.h"
+#include "lldb/Target/StopInfo.h"
+#include "lldb/Target/ThreadList.h"
+#include "lldb/Utility/DataExtractor.h"
+#include "lldb/Utility/RegisterValue.h"
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/BinaryFormat/Minidump.h"
+#include "llvm/Support/ConvertUTF.h"
+#include "llvm/Support/Error.h"
+
+#include "Plugins/Process/minidump/MinidumpTypes.h"
+
+using namespace lldb;
+using namespace lldb_private;
+using namespace llvm::minidump;
+
+void MinidumpFileBuilder::AddDirectory(StreamType type, size_t stream_size) {
+  LocationDescriptor loc;
+  loc.DataSize = static_cast<llvm::support::ulittle32_t>(stream_size);
+  // Stream will begin at the current end of data section
+  loc.RVA = static_cast<llvm::support::ulittle32_t>(GetCurrentDataEndOffset());
+
+  Directory dir;
+  dir.Type = static_cast<llvm::support::little_t<StreamType>>(type);
+  dir.Location = loc;
+
+  m_directories.push_back(dir);
+}
+
+Status MinidumpFileBuilder::AddSystemInfo(const llvm::Triple &target_triple) {
+  Status error;
+  AddDirectory(StreamType::SystemInfo, sizeof(llvm::minidump::SystemInfo));
+
+  llvm::minidump::ProcessorArchitecture arch;
+  switch (target_triple.getArch()) {
+  case llvm::Triple::ArchType::x86_64:
+    arch = ProcessorArchitecture::AMD64;
+    break;
+  case llvm::Triple::ArchType::x86:
+    arch = ProcessorArchitecture::X86;
+    break;
+  case llvm::Triple::ArchType::arm:
+    arch = ProcessorArchitecture::ARM;
+    break;
+  case llvm::Triple::ArchType::aarch64:
+    arch = ProcessorArchitecture::ARM64;
+    break;
+  case llvm::Triple::ArchType::mips64:
+  case llvm::Triple::ArchType::mips64el:
+  case llvm::Triple::ArchType::mips:
+  case llvm::Triple::ArchType::mipsel:
+    arch = ProcessorArchitecture::MIPS;
+    break;
+  case llvm::Triple::ArchType::ppc64:
+  case llvm::Triple::ArchType::ppc:
+  case llvm::Triple::ArchType::ppc64le:
+    arch = ProcessorArchitecture::PPC;
+    break;
+  default:
+    error.SetErrorStringWithFormat("Architecture %s not supported.",
+                                   target_triple.getArchName().str().c_str());
+    return error;
+  };
+
+  llvm::support::little_t<OSPlatform> platform_id;
+  switch (target_triple.getOS()) {
+  case llvm::Triple::OSType::Linux:
+    if (target_triple.getEnvironment() ==
+        llvm::Triple::EnvironmentType::Android)
+      platform_id = OSPlatform::Android;
+    else
+      platform_id = OSPlatform::Linux;
+    break;
+  case llvm::Triple::OSType::Win32:
+    platform_id = OSPlatform::Win32NT;
+    break;
+  case llvm::Triple::OSType::MacOSX:
+    platform_id = OSPlatform::MacOSX;
+    break;
+  case llvm::Triple::OSType::IOS:
+    platform_id = OSPlatform::IOS;
+    break;
+  default:
+    error.SetErrorStringWithFormat("OS %s not supported.",
+                                   target_triple.getOSName().str().c_str());
+    return error;
+  };
+
+  llvm::minidump::SystemInfo sys_info;
+  sys_info.ProcessorArch =
+      static_cast<llvm::support::little_t<ProcessorArchitecture>>(arch);
+  // Global offset to beginning of a csd_string in a data section
+  sys_info.CSDVersionRVA = static_cast<llvm::support::ulittle32_t>(
+      GetCurrentDataEndOffset() + sizeof(llvm::minidump::SystemInfo));
+  sys_info.PlatformId = platform_id;
+  m_data.AppendData(&sys_info, sizeof(llvm::minidump::SystemInfo));
+
+  std::string csd_string = "";
+
+  error = WriteString(csd_string, &m_data);
+  if (error.Fail()) {
+    error.SetErrorString("Unable to convert the csd string to UTF16.");
+    return error;
+  }
+
+  return error;
+}
+
+Status WriteString(const std::string &to_write,
+                   lldb_private::DataBufferHeap *buffer) {
+  Status error;
+  // let the StringRef eat also null termination char
+  llvm::StringRef to_write_ref(to_write.c_str(), to_write.size() + 1);
+  llvm::SmallVector<llvm::UTF16, 128> to_write_utf16;
+
+  bool converted = convertUTF8ToUTF16String(to_write_ref, to_write_utf16);
+  if (!converted) {
+    error.SetErrorStringWithFormat(
+        "Unable to convert the string to UTF16. Failed to convert %s",
+        to_write.c_str());
+    return error;
+  }
+
+  // size of the UTF16 string should be written without the null termination
+  // character that is stored in 2 bytes
+  llvm::support::ulittle32_t to_write_size(to_write_utf16.size_in_bytes() - 2);
+
+  buffer->AppendData(&to_write_size, sizeof(llvm::support::ulittle32_t));
+  buffer->AppendData(to_write_utf16.data(), to_write_utf16.size_in_bytes());
+
+  return error;
+}
+
+llvm::Expected<uint64_t> getModuleFileSize(Target &target,
+                                           const ModuleSP &mod) {
+  SectionSP sect_sp = mod->GetObjectFile()->GetBaseAddress().GetSection();
+  uint64_t SizeOfImage = 0;
+
+  if (!sect_sp) {
+    return llvm::createStringError(std::errc::operation_not_supported,
+                                   "Couldn't obtain the section information.");
+  }
+  lldb::addr_t sect_addr = sect_sp->GetLoadBaseAddress(&target);
+  // Use memory size since zero fill sections, like ".bss", will be smaller on
+  // disk.
+  lldb::addr_t sect_size = sect_sp->GetByteSize();
+  // This will usually be zero, but make sure to calculate the BaseOfImage
+  // offset.
+  const lldb::addr_t base_sect_offset =
+      mod->GetObjectFile()->GetBaseAddress().GetLoadAddress(&target) -
+      sect_addr;
+  SizeOfImage = sect_size - base_sect_offset;
+  lldb::addr_t next_sect_addr = sect_addr + sect_size;
+  Address sect_so_addr;
+  target.ResolveLoadAddress(next_sect_addr, sect_so_addr);
+  lldb::SectionSP next_sect_sp = sect_so_addr.GetSection();
+  while (next_sect_sp &&
+         next_sect_sp->GetLoadBaseAddress(&target) == next_sect_addr) {
+    sect_size = sect_sp->GetByteSize();
+    SizeOfImage += sect_size;
+    next_sect_addr += sect_size;
+    target.ResolveLoadAddress(next_sect_addr, sect_so_addr);
+    next_sect_sp = sect_so_addr.GetSection();
+  }
+
+  return SizeOfImage;
+}
+
+// ModuleList stream consists of a number of modules, followed by an array
+// of llvm::minidump::Module's structures. Every structure informs about a
+// single module. Additional data of variable length, such as module's names,
+// are stored just after the ModuleList stream. The llvm::minidump::Module
+// structures point to this helper data by global offset.
+Status MinidumpFileBuilder::AddModuleList(Target &target) {
+  constexpr size_t minidump_module_size = sizeof(llvm::minidump::Module);
+  Status error;
+
+  const ModuleList &modules = target.GetImages();
+  llvm::support::ulittle32_t modules_count =
+      static_cast<llvm::support::ulittle32_t>(modules.GetSize());
+
+  // This helps us with getting the correct global offset in minidump
+  // file later, when we will be setting up offsets from the
+  // the llvm::minidump::Module's structures into helper data
+  size_t size_before = GetCurrentDataEndOffset();
+
+  // This is the size of the main part of the ModuleList stream.
+  // It consists of a module number and corresponding number of
+  // structs describing individual modules
+  size_t module_stream_size =
+      sizeof(llvm::support::ulittle32_t) + modules_count * minidump_module_size;
+
+  // Adding directory describing this stream.
+  AddDirectory(StreamType::ModuleList, module_stream_size);
+
+  m_data.AppendData(&modules_count, sizeof(llvm::support::ulittle32_t));
+
+  // Temporary storage for the helper data (of variable length)
+  // as these cannot be dumped to m_data before dumping entire
+  // array of module structures.
+  DataBufferHeap helper_data;
+
+  for (size_t i = 0; i < modules_count; ++i) {
+    ModuleSP mod = modules.GetModuleAtIndex(i);
+    std::string module_name = mod->GetSpecificationDescription();
+    auto maybe_mod_size = getModuleFileSize(target, mod);
+    if (!maybe_mod_size) {
+      error.SetErrorStringWithFormat("Unable to get the size of module %s.",
+                                     module_name.c_str());
+      return error;
+    }
+
+    uint64_t mod_size = std::move(*maybe_mod_size);
+
+    llvm::support::ulittle32_t signature =
+        static_cast<llvm::support::ulittle32_t>(
+            static_cast<uint32_t>(minidump::CvSignature::ElfBuildId));
+    auto uuid = mod->GetUUID().GetBytes();
+
+    VSFixedFileInfo info;
+    info.Signature = static_cast<llvm::support::ulittle32_t>(0u);
+    info.StructVersion = static_cast<llvm::support::ulittle32_t>(0u);
+    info.FileVersionHigh = static_cast<llvm::support::ulittle32_t>(0u);
+    info.FileVersionLow = static_cast<llvm::support::ulittle32_t>(0u);
+    info.ProductVersionHigh = static_cast<llvm::support::ulittle32_t>(0u);
+    info.ProductVersionLow = static_cast<llvm::support::ulittle32_t>(0u);
+    info.FileFlagsMask = static_cast<llvm::support::ulittle32_t>(0u);
+    info.FileFlags = static_cast<llvm::support::ulittle32_t>(0u);
+    info.FileOS = static_cast<llvm::support::ulittle32_t>(0u);
+    info.FileType = static_cast<llvm::support::ulittle32_t>(0u);
+    info.FileSubtype = static_cast<llvm::support::ulittle32_t>(0u);
+    info.FileDateHigh = static_cast<llvm::support::ulittle32_t>(0u);
+    info.FileDateLow = static_cast<llvm::support::ulittle32_t>(0u);
+
+    LocationDescriptor ld;
+    ld.DataSize = static_cast<llvm::support::ulittle32_t>(0u);
+    ld.RVA = static_cast<llvm::support::ulittle32_t>(0u);
+
+    // Setting up LocationDescriptor for uuid string. The global offset into
+    // minidump file is calculated.
+    LocationDescriptor ld_cv;
+    ld_cv.DataSize = static_cast<llvm::support::ulittle32_t>(
+        sizeof(llvm::support::ulittle32_t) + uuid.size());
+    ld_cv.RVA = static_cast<llvm::support::ulittle32_t>(
+        size_before + module_stream_size + helper_data.GetByteSize());
+
+    helper_data.AppendData(&signature, sizeof(llvm::support::ulittle32_t));
+    helper_data.AppendData(uuid.begin(), uuid.size());
+
+    llvm::minidump::Module m;
+    m.BaseOfImage = static_cast<llvm::support::ulittle64_t>(
+        mod->GetObjectFile()->GetBaseAddress().GetLoadAddress(&target));
+    m.SizeOfImage = static_cast<llvm::support::ulittle32_t>(mod_size);
+    m.Checksum = static_cast<llvm::support::ulittle32_t>(0);
+    m.TimeDateStamp = static_cast<llvm::support::ulittle32_t>(std::time(0));
+    m.ModuleNameRVA = static_cast<llvm::support::ulittle32_t>(
+        size_before + module_stream_size + helper_data.GetByteSize());
+    m.VersionInfo = info;
+    m.CvRecord = ld_cv;
+    m.MiscRecord = ld;
+
+    error = WriteString(module_name, &helper_data);
+
+    if (error.Fail())
+      return error;
+
+    m_data.AppendData(&m, sizeof(llvm::minidump::Module));
+  }
+
+  m_data.AppendData(helper_data.GetBytes(), helper_data.GetByteSize());
+  return error;
+}
+
+uint16_t read_register_u16_raw(RegisterContext *reg_ctx,
+                               const std::string &reg_name) {
+  const RegisterInfo *reg_info = reg_ctx->GetRegisterInfoByName(reg_name);
+  if (!reg_info)
+    return 0;
+  lldb_private::RegisterValue reg_value;
+  bool success = reg_ctx->ReadRegister(reg_info, reg_value);
+  if (!success)
+    return 0;
+  return reg_value.GetAsUInt16();
+}
+
+uint32_t read_register_u32_raw(RegisterContext *reg_ctx,
+                               const std::string &reg_name) {
+  const RegisterInfo *reg_info = reg_ctx->GetRegisterInfoByName(reg_name);
+  if (!reg_info)
+    return 0;
+  lldb_private::RegisterValue reg_value;
+  bool success = reg_ctx->ReadRegister(reg_info, reg_value);
+  if (!success)
+    return 0;
+  return reg_value.GetAsUInt32();
+}
+
+uint64_t read_register_u64_raw(RegisterContext *reg_ctx,
+                               const std::string &reg_name) {
+  const RegisterInfo *reg_info = reg_ctx->GetRegisterInfoByName(reg_name);
+  if (!reg_info)
+    return 0;
+  lldb_private::RegisterValue reg_value;
+  bool success = reg_ctx->ReadRegister(reg_info, reg_value);
+  if (!success)
+    return 0;
+  return reg_value.GetAsUInt64();
+}
+
+llvm::support::ulittle16_t read_register_u16(RegisterContext *reg_ctx,
+                                             const std::string &reg_name) {
+  return static_cast<llvm::support::ulittle16_t>(
+      read_register_u16_raw(reg_ctx, reg_name));
+}
+
+llvm::support::ulittle32_t read_register_u32(RegisterContext *reg_ctx,
+                                             const std::string &reg_name) {
+  return static_cast<llvm::support::ulittle32_t>(
+      read_register_u32_raw(reg_ctx, reg_name));
+}
+
+llvm::support::ulittle64_t read_register_u64(RegisterContext *reg_ctx,
+                                             const std::string &reg_name) {
+  return static_cast<llvm::support::ulittle64_t>(
+      read_register_u64_raw(reg_ctx, reg_name));
+}
+
+lldb_private::minidump::MinidumpContext_x86_64
+GetThreadContext_64(RegisterContext *reg_ctx) {
+  lldb_private::minidump::MinidumpContext_x86_64 thread_context;
+  thread_context.context_flags = static_cast<uint32_t>(
+      lldb_private::minidump::MinidumpContext_x86_64_Flags::x86_64_Flag |
+      lldb_private::minidump::MinidumpContext_x86_64_Flags::Control |
+      lldb_private::minidump::MinidumpContext_x86_64_Flags::Segments |
+      lldb_private::minidump::MinidumpContext_x86_64_Flags::Integer);
+  thread_context.rax = read_register_u64(reg_ctx, "rax");
+  thread_context.rbx = read_register_u64(reg_ctx, "rbx");
+  thread_context.rcx = read_register_u64(reg_ctx, "rcx");
+  thread_context.rdx = read_register_u64(reg_ctx, "rdx");
+  thread_context.rdi = read_register_u64(reg_ctx, "rdi");
+  thread_context.rsi = read_register_u64(reg_ctx, "rsi");
+  thread_context.rbp = read_register_u64(reg_ctx, "rbp");
+  thread_context.rsp = read_register_u64(reg_ctx, "rsp");
+  thread_context.r8 = read_register_u64(reg_ctx, "r8");
+  thread_context.r9 = read_register_u64(reg_ctx, "r9");
+  thread_context.r10 = read_register_u64(reg_ctx, "r10");
+  thread_context.r11 = read_register_u64(reg_ctx, "r11");
+  thread_context.r12 = read_register_u64(reg_ctx, "r12");
+  thread_context.r13 = read_register_u64(reg_ctx, "r13");
+  thread_context.r14 = read_register_u64(reg_ctx, "r14");
+  thread_context.r15 = read_register_u64(reg_ctx, "r15");
+  thread_context.rip = read_register_u64(reg_ctx, "rip");
+  thread_context.eflags = read_register_u32(reg_ctx, "rflags");
+  thread_context.cs = read_register_u16(reg_ctx, "cs");
+  thread_context.fs = read_register_u16(reg_ctx, "fs");
+  thread_context.gs = read_register_u16(reg_ctx, "gs");
+  thread_context.ss = read_register_u16(reg_ctx, "ss");
+  thread_context.ds = read_register_u16(reg_ctx, "ds");
+  return thread_context;
+}
+
+// Function returns start and size of the memory region that contains
+// memory location pointed to by the current stack pointer.
+llvm::Expected<std::pair<addr_t, addr_t>>
+findStackHelper(const lldb::ProcessSP &process_sp, uint64_t rsp) {
+  MemoryRegionInfo range_info;
+  Status error = process_sp->GetMemoryRegionInfo(rsp, range_info);
+  // Skip failed memory region requests or any regions with no permissions.
+  if (error.Fail() || range_info.GetLLDBPermissions() == 0)
+    return llvm::createStringError(
+        std::errc::not_supported,
+        "unable to load stack segment of the process");
+
+  const addr_t addr = range_info.GetRange().GetRangeBase();
+  const addr_t size = range_info.GetRange().GetByteSize();
+
+  if (size == 0)
+    return llvm::createStringError(std::errc::not_supported,
+                                   "stack segment of the process is empty");
+
+  return std::make_pair(addr, size);
+}
+
+Status MinidumpFileBuilder::AddThreadList(const lldb::ProcessSP &process_sp) {
+  constexpr size_t minidump_thread_size = sizeof(llvm::minidump::Thread);
+  lldb_private::ThreadList thread_list = process_sp->GetThreadList();
+
+  // size of the entire thread stream consists of:
+  // number of threads and threads array
+  size_t thread_stream_size = sizeof(llvm::support::ulittle32_t) +
+                              thread_list.GetSize() * minidump_thread_size;
+  // save for the ability to set up RVA
+  size_t size_before = GetCurrentDataEndOffset();
+
+  AddDirectory(StreamType::ThreadList, thread_stream_size);
+
+  llvm::support::ulittle32_t thread_count =
+      static_cast<llvm::support::ulittle32_t>(thread_list.GetSize());
+  m_data.AppendData(&thread_count, sizeof(llvm::support::ulittle32_t));
+
+  DataBufferHeap helper_data;
+
+  const uint32_t num_threads = thread_list.GetSize();
+
+  for (uint32_t thread_idx = 0; thread_idx < num_threads; ++thread_idx) {
+    ThreadSP thread_sp(thread_list.GetThreadAtIndex(thread_idx));
+    RegisterContextSP reg_ctx_sp(thread_sp->GetRegisterContext());
+    Status error;
+
+    if (!reg_ctx_sp) {
+      error.SetErrorString("Unable to get the register context.");
+      return error;
+    }
+    RegisterContext *reg_ctx = reg_ctx_sp.get();
+    auto thread_context = GetThreadContext_64(reg_ctx);
+    uint64_t rsp = read_register_u64_raw(reg_ctx, "rsp");
+    auto expected_address_range = findStackHelper(process_sp, rsp);
+
+    if (!expected_address_range) {
+      error.SetErrorString("Unable to get the stack address.");
+      return error;
+    }
+
+    std::pair<uint64_t, uint64_t> range = std::move(*expected_address_range);
+    uint64_t addr = range.first;
+    uint64_t size = range.second;
+
+    auto data_up = std::make_unique<DataBufferHeap>(size, 0);
+    const size_t stack_bytes_read =
+        process_sp->ReadMemory(addr, data_up->GetBytes(), size, error);
+
+    if (error.Fail())
+      return error;
+
+    LocationDescriptor stack_memory;
+    stack_memory.DataSize =
+        static_cast<llvm::support::ulittle32_t>(stack_bytes_read);
+    stack_memory.RVA = static_cast<llvm::support::ulittle32_t>(
+        size_before + thread_stream_size + helper_data.GetByteSize());
+
+    MemoryDescriptor stack;
+    stack.StartOfMemoryRange = static_cast<llvm::support::ulittle64_t>(addr);
+    stack.Memory = stack_memory;
+
+    helper_data.AppendData(data_up->GetBytes(), stack_bytes_read);
+
+    LocationDescriptor thread_context_memory_locator;
+    thread_context_memory_locator.DataSize =
+        static_cast<llvm::support::ulittle32_t>(sizeof(thread_context));
+    thread_context_memory_locator.RVA = static_cast<llvm::support::ulittle32_t>(
+        size_before + thread_stream_size + helper_data.GetByteSize());
+
+    helper_data.AppendData(
+        &thread_context,
+        sizeof(lldb_private::minidump::MinidumpContext_x86_64));
+
+    llvm::minidump::Thread t;
+    t.ThreadId = static_cast<llvm::support::ulittle32_t>(thread_sp->GetID());
+    t.SuspendCount = static_cast<llvm::support::ulittle32_t>(
+        (thread_sp->GetState() == StateType::eStateSuspended) ? 1 : 0);
+    t.PriorityClass = static_cast<llvm::support::ulittle32_t>(0);
+    t.Priority = static_cast<llvm::support::ulittle32_t>(0);
+    t.EnvironmentBlock = static_cast<llvm::support::ulittle64_t>(0);
+    t.Stack = stack, t.Context = thread_context_memory_locator;
+
+    m_data.AppendData(&t, sizeof(llvm::minidump::Thread));
+  }
+
+  m_data.AppendData(helper_data.GetBytes(), helper_data.GetByteSize());
+  return Status();
+}
+
+Status MinidumpFileBuilder::AddException(const lldb::ProcessSP &process_sp) {
+  Status error;
+  lldb_private::ThreadList thread_list = process_sp->GetThreadList();
+
+  const uint32_t num_threads = thread_list.GetSize();
+  uint32_t stop_reason_thread_idx = 0;
+  for (stop_reason_thread_idx = 0; stop_reason_thread_idx < num_threads;
+       ++stop_reason_thread_idx) {
+    ThreadSP thread_sp(thread_list.GetThreadAtIndex(stop_reason_thread_idx));
+    StopInfoSP stop_info_sp = thread_sp->GetStopInfo();
+
+    if (stop_info_sp && stop_info_sp->IsValid())
+      break;
+  }
+
+  if (stop_reason_thread_idx == num_threads) {
+    error.SetErrorString("No stop reason thread found.");
+    return error;
+  }
+
+  constexpr size_t minidump_exception_size =
+      sizeof(llvm::minidump::ExceptionStream);
+  AddDirectory(StreamType::Exception, minidump_exception_size);
+  size_t size_before = GetCurrentDataEndOffset();
+
+  ThreadSP thread_sp(thread_list.GetThreadAtIndex(stop_reason_thread_idx));
+  RegisterContextSP reg_ctx_sp(thread_sp->GetRegisterContext());
+  RegisterContext *reg_ctx = reg_ctx_sp.get();
+  auto thread_context = GetThreadContext_64(reg_ctx);
+  StopInfoSP stop_info_sp = thread_sp->GetStopInfo();
+
+  DataBufferHeap helper_data;
+
+  LocationDescriptor thread_context_memory_locator;
+  thread_context_memory_locator.DataSize =
+      static_cast<llvm::support::ulittle32_t>(sizeof(thread_context));
+  thread_context_memory_locator.RVA = static_cast<llvm::support::ulittle32_t>(
+      size_before + minidump_exception_size + helper_data.GetByteSize());
+
+  helper_data.AppendData(
+      &thread_context, sizeof(lldb_private::minidump::MinidumpContext_x86_64));
+
+  Exception exp_record;
+  exp_record.ExceptionCode =
+      static_cast<llvm::support::ulittle32_t>(stop_info_sp->GetValue());
+  exp_record.ExceptionFlags = static_cast<llvm::support::ulittle32_t>(0);
+  exp_record.ExceptionRecord = static_cast<llvm::support::ulittle64_t>(0);
+  exp_record.ExceptionAddress = read_register_u64(reg_ctx, "rip");
+  exp_record.NumberParameters = static_cast<llvm::support::ulittle32_t>(0);
+  exp_record.UnusedAlignment = static_cast<llvm::support::ulittle32_t>(0);
+  // exp_record.ExceptionInformation;
+
+  ExceptionStream exp_stream;
+  exp_stream.ThreadId =
+      static_cast<llvm::support::ulittle32_t>(thread_sp->GetID());
+  exp_stream.UnusedAlignment = static_cast<llvm::support::ulittle32_t>(0);
+  exp_stream.ExceptionRecord = exp_record;
+  exp_stream.ThreadContext = thread_context_memory_locator;
+
+  m_data.AppendData(&exp_stream, minidump_exception_size);
+  m_data.AppendData(helper_data.GetBytes(), helper_data.GetByteSize());
+  return error;
+}
+
+lldb_private::Status
+MinidumpFileBuilder::AddMemoryList(const lldb::ProcessSP &process_sp) {
+  Status error;
+
+  if (error.Fail()) {
+    error.SetErrorString("Process doesn't support getting memory region info.");
+    return error;
+  }
+
+  // Get interesting addresses
+  std::vector<size_t> interesting_addresses;
+  auto thread_list = process_sp->GetThreadList();
+  for (size_t i = 0; i < thread_list.GetSize(); ++i) {
+    ThreadSP thread_sp(thread_list.GetThreadAtIndex(i));
+    RegisterContextSP reg_ctx_sp(thread_sp->GetRegisterContext());
+    RegisterContext *reg_ctx = reg_ctx_sp.get();
+
+    interesting_addresses.push_back(read_register_u64(reg_ctx, "rsp"));
+    interesting_addresses.push_back(read_register_u64(reg_ctx, "rip"));
+  }
+
+  DataBufferHeap helper_data;
+  std::vector<MemoryDescriptor> mem_descriptors;
+
+  std::set<addr_t> visited_region_base_addresses;
+  for (size_t interesting_address : interesting_addresses) {
+    MemoryRegionInfo range_info;
+    error = process_sp->GetMemoryRegionInfo(interesting_address, range_info);
+    // Skip failed memory region requests or any regions with no permissions.
+    if (error.Fail() || range_info.GetLLDBPermissions() == 0)
+      continue;
+    const addr_t addr = range_info.GetRange().GetRangeBase();
+    // Skip any regions we have already saved out.
+    if (visited_region_base_addresses.insert(addr).second == false)
+      continue;
+    const addr_t size = range_info.GetRange().GetByteSize();
+    if (size == 0)
+      continue;
+    auto data_up = std::make_unique<DataBufferHeap>(size, 0);
+    const size_t bytes_read =
+        process_sp->ReadMemory(addr, data_up->GetBytes(), size, error);
+    if (bytes_read == 0)
+      continue;
+    // We have a good memory region with valid bytes to store.
+    LocationDescriptor memory_dump;
+    memory_dump.DataSize = static_cast<llvm::support::ulittle32_t>(bytes_read);
+    memory_dump.RVA =
+        static_cast<llvm::support::ulittle32_t>(GetCurrentDataEndOffset());
+    MemoryDescriptor memory_desc;
+    memory_desc.StartOfMemoryRange =
+        static_cast<llvm::support::ulittle64_t>(addr);
+    memory_desc.Memory = memory_dump;
+    mem_descriptors.push_back(memory_desc);
+    m_data.AppendData(data_up->GetBytes(), bytes_read);
+  }
+
+  AddDirectory(StreamType::MemoryList,
+               sizeof(llvm::support::ulittle32_t) +
+                   mem_descriptors.size() *
+                       sizeof(llvm::minidump::MemoryDescriptor));
+  llvm::support::ulittle32_t memory_ranges_num(mem_descriptors.size());
+
+  m_data.AppendData(&memory_ranges_num, sizeof(llvm::support::ulittle32_t));
+  for (auto memory_descriptor : mem_descriptors) {
+    m_data.AppendData(&memory_descriptor,
+                      sizeof(llvm::minidump::MemoryDescriptor));
+  }
+
+  return error;
+}
+
+void MinidumpFileBuilder::AddMiscInfo(const lldb::ProcessSP &process_sp) {
+  AddDirectory(StreamType::MiscInfo,
+               sizeof(lldb_private::minidump::MinidumpMiscInfo));
+
+  lldb_private::minidump::MinidumpMiscInfo misc_info;
+  misc_info.size = static_cast<llvm::support::ulittle32_t>(
+      sizeof(lldb_private::minidump::MinidumpMiscInfo));
+  // Default set flags1 to 0, in case that we will not be able to
+  // get any information
+  misc_info.flags1 = static_cast<llvm::support::ulittle32_t>(0);
+
+  lldb_private::ProcessInstanceInfo process_info;
+  process_sp->GetProcessInfo(process_info);
+  if (process_info.ProcessIDIsValid()) {
+    // Set flags1 to reflect that PID is filled in
+    misc_info.flags1 =
+        static_cast<llvm::support::ulittle32_t>(static_cast<uint32_t>(
+            lldb_private::minidump::MinidumpMiscInfoFlags::ProcessID));
+    misc_info.process_id =
+        static_cast<llvm::support::ulittle32_t>(process_info.GetProcessID());
+  }
+
+  m_data.AppendData(&misc_info,
+                    sizeof(lldb_private::minidump::MinidumpMiscInfo));
+}
+
+std::unique_ptr<llvm::MemoryBuffer>
+getFileStreamHelper(const std::string &path) {
+  auto maybe_stream = llvm::MemoryBuffer::getFileAsStream(path);
+  if (!maybe_stream)
+    return nullptr;
+  return std::move(maybe_stream.get());
+}
+
+void MinidumpFileBuilder::AddLinuxFileStreams(
+    const lldb::ProcessSP &process_sp) {
+  std::vector<std::pair<StreamType, std::string>> files_with_stream_types = {
+      {StreamType::LinuxCPUInfo, "/proc/cpuinfo"},
+      {StreamType::LinuxLSBRelease, "/etc/lsb-release"},
+  };
+
+  lldb_private::ProcessInstanceInfo process_info;
+  process_sp->GetProcessInfo(process_info);
+  if (process_info.ProcessIDIsValid()) {
+    lldb::pid_t pid = process_info.GetProcessID();
+    std::string pid_str = std::to_string(pid);
+    files_with_stream_types.push_back(
+        {StreamType::LinuxProcStatus, "/proc/" + pid_str + "/status"});
+    files_with_stream_types.push_back(
+        {StreamType::LinuxCMDLine, "/proc/" + pid_str + "/cmdline"});
+    files_with_stream_types.push_back(
+        {StreamType::LinuxEnviron, "/proc/" + pid_str + "/environ"});
+    files_with_stream_types.push_back(
+        {StreamType::LinuxAuxv, "/proc/" + pid_str + "/auxv"});
+    files_with_stream_types.push_back(
+        {StreamType::LinuxMaps, "/proc/" + pid_str + "/maps"});
+    files_with_stream_types.push_back(
+        {StreamType::LinuxProcStat, "/proc/" + pid_str + "/stat"});
+    files_with_stream_types.push_back(
+        {StreamType::LinuxProcFD, "/proc/" + pid_str + "/fd"});
+  }
+
+  for (const auto &entry : files_with_stream_types) {
+    StreamType stream = entry.first;
+    std::string path = entry.second;
+    auto memory_buffer = getFileStreamHelper(path);
+
+    if (memory_buffer) {
+      size_t size = memory_buffer->getBufferSize();
+      if (size == 0)
+        continue;
+      AddDirectory(stream, size);
+      m_data.AppendData(memory_buffer->getBufferStart(), size);
+    }
+  }
+}
+
+Status MinidumpFileBuilder::Dump(lldb::FileUP &core_file) const {
+  constexpr size_t header_size = sizeof(llvm::minidump::Header);
+  constexpr size_t directory_size = sizeof(llvm::minidump::Directory);
+
+  // write header
+  llvm::minidump::Header header;
+  header.Signature = static_cast<llvm::support::ulittle32_t>(
+      llvm::minidump::Header::MagicSignature);
+  header.Version = static_cast<llvm::support::ulittle32_t>(
+      llvm::minidump::Header::MagicVersion);
+  header.NumberOfStreams =
+      static_cast<llvm::support::ulittle32_t>(GetDirectoriesNum());
+  header.StreamDirectoryRVA =
+      static_cast<llvm::support::ulittle32_t>(GetCurrentDataEndOffset());
+  header.Checksum = static_cast<llvm::support::ulittle32_t>(
+      0u), // not used in most of the writers
+      header.TimeDateStamp =
+          static_cast<llvm::support::ulittle32_t>(std::time(0));
+  header.Flags =
+      static_cast<llvm::support::ulittle64_t>(0u); // minidump normal flag
+
+  Status error;
+  size_t bytes_written;
+
+  bytes_written = header_size;
+  error = core_file->Write(&header, bytes_written);
+  if (error.Fail() || bytes_written != header_size) {
+    if (bytes_written != header_size)
+      error.SetErrorStringWithFormat(
+          "Unable to write the header. (written %ld/%ld).", bytes_written,
+          header_size);
+    return error;
+  }
+
+  // write data
+  bytes_written = m_data.GetByteSize();
+  error = core_file->Write(m_data.GetBytes(), bytes_written);
+  if (error.Fail() || bytes_written != m_data.GetByteSize()) {
+    if (bytes_written != m_data.GetByteSize())
+      error.SetErrorStringWithFormat(
+          "Unable to write the data. (written %ld/%ld).", bytes_written,
+          m_data.GetByteSize());
+    return error;
+  }
+
+  // write directories
+  for (const Directory &dir : m_directories) {
+    bytes_written = directory_size;
+    error = core_file->Write(&dir, bytes_written);
+    if (error.Fail() || bytes_written != directory_size) {
+      if (bytes_written != directory_size)
+        error.SetErrorStringWithFormat(
+            "Unable to write the directory. (written %ld/%ld).", bytes_written,
+            directory_size);
+      return error;
+    }
+  }
+
+  return error;
+}
+
+size_t MinidumpFileBuilder::GetDirectoriesNum() const {
+  return m_directories.size();
+}
+
+size_t MinidumpFileBuilder::GetCurrentDataEndOffset() const {
+  return sizeof(llvm::minidump::Header) + m_data.GetByteSize();
+}
 No newline at end of file

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

+//===-- ObjectFileMinidump.h ---------------------------------- -*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+/// \file
+/// Placeholder plugin for the save core functionality.
+///
+/// ObjectFileMinidump is created only to be able to save minidump core files
+/// from existing processes with the ObjectFileMinidump::SaveCore function.
+/// Minidump files are not ObjectFile objects, but they are core files and
+/// currently LLDB's ObjectFile plug-ins handle emitting core files. If the
+/// core file saving ever moves into a new plug-in type within LLDB, this code
+/// should move as well, but for now this is the best place architecturally.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_SOURCE_PLUGINS_OBJECTFILE_MINIDUMP_OBJECTFILEMINIDUMP_H
+#define LLDB_SOURCE_PLUGINS_OBJECTFILE_MINIDUMP_OBJECTFILEMINIDUMP_H
+
+#include "lldb/Symbol/ObjectFile.h"
+#include "lldb/Utility/ArchSpec.h"
+
+class ObjectFileMinidump : public lldb_private::PluginInterface {
+public:
+  // Static Functions
+  static void Initialize();
+  static void Terminate();
+
+  static lldb_private::ConstString GetPluginNameStatic();
+  static const char *GetPluginDescriptionStatic() {
+    return "Minidump object file.";
+  }
+
+  // PluginInterface protocol
+  lldb_private::ConstString GetPluginName() override {
+    return GetPluginNameStatic();
+  }
+
+  static lldb_private::ObjectFile *
+  CreateInstance(const lldb::ModuleSP &module_sp, lldb::DataBufferSP &data_sp,
+                 lldb::offset_t data_offset, const lldb_private::FileSpec *file,
+                 lldb::offset_t offset, lldb::offset_t length);
+
+  static lldb_private::ObjectFile *CreateMemoryInstance(
+      const lldb::ModuleSP &module_sp, lldb::DataBufferSP &data_sp,
+      const lldb::ProcessSP &process_sp, lldb::addr_t header_addr);
+
+  static size_t GetModuleSpecifications(const lldb_private::FileSpec &file,
+                                        lldb::DataBufferSP &data_sp,
+                                        lldb::offset_t data_offset,
+                                        lldb::offset_t file_offset,
+                                        lldb::offset_t length,
+                                        lldb_private::ModuleSpecList &specs);
+
+  uint32_t GetPluginVersion() override { return 1; }
+
+  // Saves dump in Minidump file format
+  static bool SaveCore(const lldb::ProcessSP &process_sp,
+                       const lldb_private::FileSpec &outfile,
+                       lldb::SaveCoreStyle &core_style,
+                       lldb_private::Status &error);
+
+private:
+  ObjectFileMinidump() = default;
+};
+
+#endif // LLDB_SOURCE_PLUGINS_OBJECTFILE_MINIDUMP_OBJECTFILEMINIDUMP_H
 No newline at end of file

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

+//===-- ObjectFileMinidump.cpp --------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "ObjectFileMinidump.h"
+
+#include "MinidumpFileBuilder.h"
+
+#include "lldb/Core/ModuleSpec.h"
+#include "lldb/Core/PluginManager.h"
+#include "lldb/Core/Section.h"
+#include "lldb/Target/Process.h"
+
+#include "llvm/Support/FileSystem.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+LLDB_PLUGIN_DEFINE(ObjectFileMinidump)
+
+void ObjectFileMinidump::Initialize() {
+  PluginManager::RegisterPlugin(
+      GetPluginNameStatic(), GetPluginDescriptionStatic(), CreateInstance,
+      CreateMemoryInstance, GetModuleSpecifications, SaveCore);
+}
+
+void ObjectFileMinidump::Terminate() {
+  PluginManager::UnregisterPlugin(CreateInstance);
+}
+
+ConstString ObjectFileMinidump::GetPluginNameStatic() {
+  static ConstString g_name("minidump");
+  return g_name;
+}
+
+ObjectFile *ObjectFileMinidump::CreateInstance(
+    const lldb::ModuleSP &module_sp, lldb::DataBufferSP &data_sp,
+    lldb::offset_t data_offset, const lldb_private::FileSpec *file,
+    lldb::offset_t offset, lldb::offset_t length) {
+  return nullptr;
+}
+
+ObjectFile *ObjectFileMinidump::CreateMemoryInstance(
+    const lldb::ModuleSP &module_sp, DataBufferSP &data_sp,
+    const ProcessSP &process_sp, lldb::addr_t header_addr) {
+  return nullptr;
+}
+
+size_t ObjectFileMinidump::GetModuleSpecifications(
+    const lldb_private::FileSpec &file, lldb::DataBufferSP &data_sp,
+    lldb::offset_t data_offset, lldb::offset_t file_offset,
+    lldb::offset_t length, lldb_private::ModuleSpecList &specs) {
+  specs.Clear();
+  return 0;
+}
+
+bool ObjectFileMinidump::SaveCore(const lldb::ProcessSP &process_sp,
+                                  const lldb_private::FileSpec &outfile,
+                                  lldb::SaveCoreStyle &core_style,
+                                  lldb_private::Status &error) {
+  if (core_style != SaveCoreStyle::eSaveCoreStackOnly) {
+    error.SetErrorString("Only stack minidumps supported yet.");
+    return false;
+  }
+
+  if (!process_sp)
+    return false;
+
+  MinidumpFileBuilder builder;
+
+  Target &target = process_sp->GetTarget();
+
+  error = builder.AddSystemInfo(target.GetArchitecture().GetTriple());
+  if (error.Fail())
+    return false;
+
+  error = builder.AddModuleList(target);
+  if (error.Fail())
+    return false;
+
+  builder.AddMiscInfo(process_sp);
+
+  if (target.GetArchitecture().GetMachine() == llvm::Triple::ArchType::x86_64) {
+    error = builder.AddThreadList(process_sp);
+    if (error.Fail())
+      return false;
+
+    error = builder.AddException(process_sp);
+    if (error.Fail())
+      return false;
+
+    error = builder.AddMemoryList(process_sp);
+    if (error.Fail())
+      return false;
+  }
+
+  if (target.GetArchitecture().GetTriple().getOS() ==
+      llvm::Triple::OSType::Linux) {
+    builder.AddLinuxFileStreams(process_sp);
+  }
+
+  llvm::Expected<lldb::FileUP> maybe_core_file = FileSystem::Instance().Open(
+      outfile, File::eOpenOptionWriteOnly | File::eOpenOptionCanCreate);
+  if (!maybe_core_file) {
+    error = maybe_core_file.takeError();
+    return false;
+  }
+  lldb::FileUP core_file = std::move(maybe_core_file.get());
+
+  error = builder.Dump(core_file);
+  if (error.Fail())
+    return false;
+
+  return true;
+}

lldb/test/API/functionalities/process_save_core_minidump/Makefile

+CXX_SOURCES := main.cpp
+
+CFLAGS_EXTRAS := -lpthread
+
+include Makefile.rules
+

lldb/test/API/functionalities/process_save_core_minidump/TestProcessSaveCoreMinidump.py

+"""
+Test saving a mini dump.
+"""
+
+
+import os
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class ProcessSaveCoreMinidumpTestCase(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    @skipUnlessArch("x86_64")
+    @skipUnlessPlatform(["linux"])
+    def test_save_linux_mini_dump(self):
+        """Test that we can save a Linux mini dump."""
+        self.build()
+        exe = self.getBuildArtifact("a.out")
+        core = self.getBuildArtifact("core.dmp")
+        try:
+            target = self.dbg.CreateTarget(exe)
+            process = target.LaunchSimple(
+                None, None, self.get_process_working_directory())
+            self.assertEqual(process.GetState(), lldb.eStateStopped)
+
+            # get neccessary data for the verification phase
+            process_info = process.GetProcessInfo()
+            expected_pid = process_info.GetProcessID() if process_info.IsValid() else -1
+            expected_number_of_modules = target.GetNumModules()
+            expected_modules = target.modules
+            expected_number_of_threads = process.GetNumThreads()
+            expected_threads = []
+
+            for thread_idx in range(process.GetNumThreads()):
+                thread = process.GetThreadAtIndex(thread_idx)
+                thread_id = thread.GetThreadID()
+                expected_threads.append(thread_id)
+
+            # save core and, kill process and verify corefile existence
+            self.runCmd("process save-core --plugin-name=minidump --style=stack " + core)
+            self.assertTrue(os.path.isfile(core))
+            self.assertTrue(process.Kill().Success())
+
+            # To verify, we'll launch with the mini dump
+            target = self.dbg.CreateTarget(None)
+            process = target.LoadCore(core)
+
+            # check if the core is in desired state
+            self.assertTrue(process, PROCESS_IS_VALID)
+            self.assertTrue(process.GetProcessInfo().IsValid())
+            self.assertEqual(process.GetProcessInfo().GetProcessID(), expected_pid)
+            self.assertTrue(target.GetTriple().find("linux") != -1)
+            self.assertTrue(target.GetNumModules(), expected_number_of_modules)
+            self.assertEqual(process.GetNumThreads(), expected_number_of_threads)
+
+            for module, expected in zip(target.modules, expected_modules):
+                self.assertTrue(module.IsValid())
+                module_file_name = module.GetFileSpec().GetFilename()
+                expected_file_name = expected.GetFileSpec().GetFilename()
+                # skip kernel virtual dynamic shared objects
+                if "vdso" in expected_file_name:
+                    continue
+                self.assertEqual(module_file_name, expected_file_name)
+                self.assertEqual(module.GetUUIDString(), expected.GetUUIDString())
+
+            for thread_idx in range(process.GetNumThreads()):
+                thread = process.GetThreadAtIndex(thread_idx)
+                self.assertTrue(thread.IsValid())
+                thread_id = thread.GetThreadID()
+                self.assertTrue(thread_id in expected_threads)
+        finally:
+            # Clean up the mini dump file.
+            self.assertTrue(self.dbg.DeleteTarget(target))
+            if (os.path.isfile(core)):
+                os.unlink(core)

lldb/test/API/functionalities/process_save_core_minidump/main.cpp

+#include <cassert>
+#include <iostream>
+#include <thread>
+
+using namespace std;
+
+void g() { assert(false); }
+
+void f() { g(); }
+
+size_t h() {
+  size_t sum = 0;
+  for (size_t i = 0; i < 1000000; ++i)
+    for (size_t j = 0; j < 1000000; ++j)
+      if ((i * j) % 2 == 0) {
+        sum += 1;
+      }
+  return sum;
+}
+
+int main() {
+  thread t1(f);
+
+  size_t x = h();
+
+  t1.join();
+
+  cout << "X is " << x << "\n";
+  return 0;
+}
 No newline at end of file