[Lldb-commits] [PATCH] D100267: [lldb] [gdb-remote client] Remove breakpoints throughout vfork

[Michał Górny via Phabricator via lldb-commits]

mgorny updated this revision to Diff 369869.
mgorny added a comment.

Try another approach for getting trap size.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D100267/new/

https://reviews.llvm.org/D100267

Files:
  lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
  lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
  lldb/test/Shell/Subprocess/vfork-follow-parent-softbp.test


Index: lldb/test/Shell/Subprocess/vfork-follow-parent-softbp.test
===================================================================
--- /dev/null
+++ lldb/test/Shell/Subprocess/vfork-follow-parent-softbp.test
@@ -0,0 +1,13 @@
+# REQUIRES: native
+# UNSUPPORTED: system-darwin
+# UNSUPPORTED: system-windows
+# RUN: %clangxx_host %p/Inputs/fork.cpp -DTEST_FORK=vfork -o %t
+# RUN: %lldb -b -s %s %t | FileCheck %s
+b parent_func
+b child_func
+process launch
+# CHECK-NOT: function run in parent
+# CHECK: stop reason = breakpoint
+continue
+# CHECK: function run in parent
+# CHECK: child exited: 0
Index: lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
+++ lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
@@ -232,6 +232,7 @@
 
   void DidFork(lldb::pid_t child_pid, lldb::tid_t child_tid) override;
   void DidVFork(lldb::pid_t child_pid, lldb::tid_t child_tid) override;
+  void DidVForkDone() override;
 
 protected:
   friend class ThreadGDBRemote;
@@ -296,6 +297,8 @@
   using FlashRange = FlashRangeVector::Entry;
   FlashRangeVector m_erased_flash_ranges;
 
+  bool m_vfork_in_progress;
+
   // Accessors
   bool IsRunning(lldb::StateType state) {
     return state == lldb::eStateRunning || IsStepping(state);
Index: lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -265,7 +265,8 @@
       m_waiting_for_attach(false), m_destroy_tried_resuming(false),
       m_command_sp(), m_breakpoint_pc_offset(0),
       m_initial_tid(LLDB_INVALID_THREAD_ID), m_replay_mode(false),
-      m_allow_flash_writes(false), m_erased_flash_ranges() {
+      m_allow_flash_writes(false), m_erased_flash_ranges(),
+      m_vfork_in_progress(false) {
   m_async_broadcaster.SetEventName(eBroadcastBitAsyncThreadShouldExit,
                                    "async thread should exit");
   m_async_broadcaster.SetEventName(eBroadcastBitAsyncContinue,
@@ -5492,7 +5493,7 @@
          bp_site->GetType() == BreakpointSite::eExternal)) {
       m_gdb_comm.SendGDBStoppointTypePacket(
           eBreakpointSoftware, enable, bp_site->GetLoadAddress(),
-          bp_site->GetTrapOpcodeMaxByteSize(), GetInterruptTimeout());
+          GetSoftwareBreakpointTrapOpcode(bp_site), GetInterruptTimeout());
     }
   });
 }
@@ -5534,6 +5535,13 @@
 void ProcessGDBRemote::DidVFork(lldb::pid_t child_pid, lldb::tid_t child_tid) {
   Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_PROCESS));
 
+  assert(!m_vfork_in_progress);
+  m_vfork_in_progress = true;
+
+  // Disable all software breakpoints for the duration of vfork.
+  if (m_gdb_comm.SupportsGDBStoppointPacket(eBreakpointSoftware))
+    DidForkSwitchSoftwareBreakpoints(false);
+
   LLDB_LOG(log, "Detaching forked child {0}", child_pid);
   Status error = m_gdb_comm.Detach(false, child_pid);
   if (error.Fail()) {
@@ -5543,3 +5551,12 @@
       return;
   }
 }
+
+void ProcessGDBRemote::DidVForkDone() {
+  assert(m_vfork_in_progress);
+  m_vfork_in_progress = false;
+
+  // Reenable all software breakpoints that were enabled before vfork.
+  if (m_gdb_comm.SupportsGDBStoppointPacket(eBreakpointSoftware))
+    DidForkSwitchSoftwareBreakpoints(true);
+}


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