[Lldb-commits] [lldb] [lldb/Target] Delay image loading after corefile process creation (PR #70351)

[Med Ismail Bennani via lldb-commits]

https://github.com/medismailben created https://github.com/llvm/llvm-project/pull/70351

This patch is a follow-up to db223b7f01f7. Similarly to it, it changes the timing of binary image loading for the ProcessMachCore plugin.

This issue came up after getting reports of scripting resources that would fail to execute because they relied on data provided by the corefile process (i.e. for reading memory). However, rior to this change, the scripting resource loading would happen as part of the binary image loading, which in turns happened before the process finished being created.

This patch address that issue by delaying the binary image loading phase until we receive the corefile process stop event event, ensuring that the process is fully formed.

>From 81ace8b87271098c3c9dd615d2dc401b9414ea37 Mon Sep 17 00:00:00 2001
From: Med Ismail Bennani <ismail at bennani.ma>
Date: Thu, 26 Oct 2023 01:11:02 -0700
Subject: [PATCH] [lldb/Target] Delay image loading after corefile process
 creation

This patch is a follow-up to db223b7f01f7. Similarly to it, it changes
the timing of binary image loading for the ProcessMachCore plugin.

This issue came up after getting reports of scripting resources that
would fail to execute because they relied on data provided by the corefile
process (i.e. for reading memory). However, rior to this change, the
scripting resource loading would happen as part of the binary image
loading, which in turns happened before the process finished being created.

This patch address that issue by delaying the binary image loading phase
until we receive the corefile process stop event event, ensuring that the
process is fully formed.

Signed-off-by: Med Ismail Bennani <ismail at bennani.ma>
---
 lldb/include/lldb/Target/Process.h            |  2 ++
 .../Process/mach-core/ProcessMachCore.cpp     |  4 +--
 .../Process/mach-core/ProcessMachCore.h       |  2 ++
 lldb/source/Target/Process.cpp                | 29 ++++++++++---------
 4 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/lldb/include/lldb/Target/Process.h b/lldb/include/lldb/Target/Process.h
index a6d3e6c2d16926e..e25e82302a56dd9 100644
--- a/lldb/include/lldb/Target/Process.h
+++ b/lldb/include/lldb/Target/Process.h
@@ -614,6 +614,8 @@ class Process : public std::enable_shared_from_this<Process>,
     return error;
   }
 
+  virtual void DidLoadCore() {}
+
   /// The "ShadowListener" for a process is just an ordinary Listener that 
   /// listens for all the Process event bits.  It's convenient because you can
   /// specify it in the LaunchInfo or AttachInfo, so it will get events from
diff --git a/lldb/source/Plugins/Process/mach-core/ProcessMachCore.cpp b/lldb/source/Plugins/Process/mach-core/ProcessMachCore.cpp
index b11062a0224abc2..9b10a0b832915d3 100644
--- a/lldb/source/Plugins/Process/mach-core/ProcessMachCore.cpp
+++ b/lldb/source/Plugins/Process/mach-core/ProcessMachCore.cpp
@@ -570,8 +570,6 @@ Status ProcessMachCore::DoLoadCore() {
 
   CreateMemoryRegions();
 
-  LoadBinariesAndSetDYLD();
-
   CleanupMemoryRegionPermissions();
 
   AddressableBits addressable_bits = core_objfile->GetAddressableBits();
@@ -580,6 +578,8 @@ Status ProcessMachCore::DoLoadCore() {
   return error;
 }
 
+void ProcessMachCore::DidLoadCore() { LoadBinariesAndSetDYLD(); }
+
 lldb_private::DynamicLoader *ProcessMachCore::GetDynamicLoader() {
   if (m_dyld_up.get() == nullptr)
     m_dyld_up.reset(DynamicLoader::FindPlugin(this, m_dyld_plugin_name));
diff --git a/lldb/source/Plugins/Process/mach-core/ProcessMachCore.h b/lldb/source/Plugins/Process/mach-core/ProcessMachCore.h
index c8820209e3f3830..0e61daa625b53cc 100644
--- a/lldb/source/Plugins/Process/mach-core/ProcessMachCore.h
+++ b/lldb/source/Plugins/Process/mach-core/ProcessMachCore.h
@@ -46,6 +46,8 @@ class ProcessMachCore : public lldb_private::PostMortemProcess {
   // Creating a new process, or attaching to an existing one
   lldb_private::Status DoLoadCore() override;
 
+  void DidLoadCore() override;
+
   lldb_private::DynamicLoader *GetDynamicLoader() override;
 
   // PluginInterface protocol
diff --git a/lldb/source/Target/Process.cpp b/lldb/source/Target/Process.cpp
index f82ab05362fbee9..f4bacf314dd746a 100644
--- a/lldb/source/Target/Process.cpp
+++ b/lldb/source/Target/Process.cpp
@@ -2639,19 +2639,6 @@ Status Process::LoadCore() {
     else
       StartPrivateStateThread();
 
-    DynamicLoader *dyld = GetDynamicLoader();
-    if (dyld)
-      dyld->DidAttach();
-
-    GetJITLoaders().DidAttach();
-
-    SystemRuntime *system_runtime = GetSystemRuntime();
-    if (system_runtime)
-      system_runtime->DidAttach();
-
-    if (!m_os_up)
-      LoadOperatingSystemPlugin(false);
-
     // We successfully loaded a core file, now pretend we stopped so we can
     // show all of the threads in the core file and explore the crashed state.
     SetPrivateState(eStateStopped);
@@ -2668,7 +2655,23 @@ Status Process::LoadCore() {
                 StateAsCString(state));
       error.SetErrorString(
           "Did not get stopped event after loading the core file.");
+    } else {
+      DidLoadCore();
+
+      DynamicLoader *dyld = GetDynamicLoader();
+      if (dyld)
+        dyld->DidAttach();
+
+      GetJITLoaders().DidAttach();
+
+      SystemRuntime *system_runtime = GetSystemRuntime();
+      if (system_runtime)
+        system_runtime->DidAttach();
+
+      if (!m_os_up)
+        LoadOperatingSystemPlugin(false);
     }
+
     RestoreProcessEvents();
   }
   return error;