Add the ability to process save-core stack-memory-only corefiles

Add a field to the qMemoryRegionInfo packet where the remote stub
can describe the type of memory -- heap, stack.  Keep track of
memory regions that are stack memory in lldb.  Add a new "--style
stack" to process save-core to request that only stack memory be
included in the corefile.

Differential Revision: https://reviews.llvm.org/D107625

3 files changed, 57 insertions, 21 deletions

diff --git a/lldb/source/Commands/CommandObjectProcess.cpp b/lldb/source/Commands/CommandObjectProcess.cpp
index 1a8ed021b9f0..c65b661f9cfc 100644
--- a/lldb/source/Commands/CommandObjectProcess.cpp
+++ b/lldb/source/Commands/CommandObjectProcess.cpp
@@ -1166,7 +1166,9 @@ protected:
 static constexpr OptionEnumValueElement g_corefile_save_style[] = {
     {eSaveCoreFull, "full", "Create a core file with all memory saved"},
     {eSaveCoreDirtyOnly, "modified-memory",
-     "Create a corefile with only modified memory saved"}};
+     "Create a corefile with only modified memory saved"},
+    {eSaveCoreStackOnly, "stack",
+     "Create a corefile with only stack  memory saved"}};
 
 static constexpr OptionEnumValues SaveCoreStyles() {
   return OptionEnumValues(g_corefile_save_style);
@@ -1237,11 +1239,12 @@ protected:
         Status error =
             PluginManager::SaveCore(process_sp, output_file, corefile_style);
         if (error.Success()) {
-          if (corefile_style == SaveCoreStyle::eSaveCoreDirtyOnly) {
+          if (corefile_style == SaveCoreStyle::eSaveCoreDirtyOnly ||
+              corefile_style == SaveCoreStyle::eSaveCoreStackOnly) {
             result.AppendMessageWithFormat(
-                "\nModified-memory only corefile "
-                "created.  This corefile may not show \n"
-                "library/framework/app binaries "
+                "\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"
                 "those binaries have "
                 "been updated/modified. Copies are not included\n"
diff --git a/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp b/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
index ce5324943171..decccc494bc0 100644
--- a/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
+++ b/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
@@ -6342,13 +6342,17 @@ struct segment_vmaddr {
 // are some multiple passes over the image list while calculating
 // everything.
 
-static offset_t
-CreateAllImageInfosPayload(const lldb::ProcessSP &process_sp,
-                           offset_t initial_file_offset,
-                           StreamString &all_image_infos_payload) {
+static offset_t CreateAllImageInfosPayload(
+    const lldb::ProcessSP &process_sp, offset_t initial_file_offset,
+    StreamString &all_image_infos_payload, SaveCoreStyle core_style) {
   Target &target = process_sp->GetTarget();
-  const ModuleList &modules = target.GetImages();
-  size_t modules_count = modules.GetSize();
+  ModuleList modules = target.GetImages();
+
+  // stack-only corefiles have no reason to include binaries that
+  // are not executing; we're trying to make the smallest corefile
+  // we can, so leave the rest out.
+  if (core_style == SaveCoreStyle::eSaveCoreStackOnly)
+    modules.Clear();
 
   std::set<std::string> executing_uuids;
   ThreadList &thread_list(process_sp->GetThreadList());
@@ -6363,10 +6367,12 @@ CreateAllImageInfosPayload(const lldb::ProcessSP &process_sp,
         UUID uuid = module_sp->GetUUID();
         if (uuid.IsValid()) {
           executing_uuids.insert(uuid.GetAsString());
+          modules.AppendIfNeeded(module_sp);
         }
       }
     }
   }
+  size_t modules_count = modules.GetSize();
 
   struct all_image_infos_header infos;
   infos.version = 1;
@@ -6508,12 +6514,9 @@ bool ObjectFileMachO::SaveCore(const lldb::ProcessSP &process_sp,
   if (!process_sp)
     return false;
 
-  // For Mach-O, we can only create full corefiles or dirty-page-only
-  // corefiles.  The default is dirty-page-only.
-  if (core_style != SaveCoreStyle::eSaveCoreFull) {
+  // Default on macOS is to create a dirty-memory-only corefile.
+  if (core_style == SaveCoreStyle::eSaveCoreUnspecified) {
     core_style = SaveCoreStyle::eSaveCoreDirtyOnly;
-  } else {
-    core_style = SaveCoreStyle::eSaveCoreFull;
   }
 
   Target &target = process_sp->GetTarget();
@@ -6568,13 +6571,23 @@ bool ObjectFileMachO::SaveCore(const lldb::ProcessSP &process_sp,
           if (size == 0)
             break;
 
-          if (prot != 0) {
+          bool include_this_region = true;
+          bool dirty_pages_only = false;
+          if (core_style == SaveCoreStyle::eSaveCoreStackOnly) {
+            dirty_pages_only = true;
+            if (range_info.IsStackMemory() != MemoryRegionInfo::eYes) {
+              include_this_region = false;
+            }
+          }
+          if (core_style == SaveCoreStyle::eSaveCoreDirtyOnly) {
+            dirty_pages_only = true;
+          }
+
+          if (prot != 0 && include_this_region) {
             addr_t pagesize = range_info.GetPageSize();
             const llvm::Optional<std::vector<addr_t>> &dirty_page_list =
                 range_info.GetDirtyPageList();
-            if (core_style == SaveCoreStyle::eSaveCoreDirtyOnly &&
-                dirty_page_list.hasValue()) {
-              core_style = SaveCoreStyle::eSaveCoreDirtyOnly;
+            if (dirty_pages_only && dirty_page_list.hasValue()) {
               for (addr_t dirtypage : dirty_page_list.getValue()) {
                 page_object obj;
                 obj.addr = dirtypage;
@@ -6617,6 +6630,12 @@ bool ObjectFileMachO::SaveCore(const lldb::ProcessSP &process_sp,
           last_obj = obj;
         }
 
+        // If we only ended up with one contiguous memory segment
+        if (combined_page_objects.size() == 0 &&
+            last_obj.addr != LLDB_INVALID_ADDRESS) {
+          combined_page_objects.push_back(last_obj);
+        }
+
         for (page_object obj : combined_page_objects) {
           uint32_t cmd_type = LC_SEGMENT_64;
           uint32_t segment_size = sizeof(llvm::MachO::segment_command_64);
@@ -6767,7 +6786,8 @@ bool ObjectFileMachO::SaveCore(const lldb::ProcessSP &process_sp,
         all_image_infos_lcnote_up->name = "all image infos";
         all_image_infos_lcnote_up->payload_file_offset = file_offset;
         file_offset = CreateAllImageInfosPayload(
-            process_sp, file_offset, all_image_infos_lcnote_up->payload);
+            process_sp, file_offset, all_image_infos_lcnote_up->payload,
+            core_style);
         lc_notes.push_back(std::move(all_image_infos_lcnote_up));
 
         // Add LC_NOTE load commands
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
index ee8c7c66573d..e898a08641dc 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -1572,6 +1572,19 @@ Status GDBRemoteCommunicationClient::GetMemoryRegionInfo(
               }
             }
           }
+        } else if (name.equals("type")) {
+          std::string comma_sep_str = value.str();
+          size_t comma_pos;
+          while ((comma_pos = comma_sep_str.find(',')) != std::string::npos) {
+            comma_sep_str[comma_pos] = '\0';
+            if (comma_sep_str == "stack") {
+              region_info.SetIsStackMemory(MemoryRegionInfo::eYes);
+            }
+          }
+          // handle final (or only) type of "stack"
+          if (comma_sep_str == "stack") {
+            region_info.SetIsStackMemory(MemoryRegionInfo::eYes);
+          }
         } else if (name.equals("error")) {
           StringExtractorGDBRemote error_extractor(value);
           std::string error_string;