Re-land r313210 - Fix for bug 34532 - A few rough corners related to post-mortem debugging (core/minidump)

The main change is to avoid setting the process state as running when
debugging core/minidumps (details in the bug).  Also included a few small,
related fixes around how the errors propagate in this case.

Fixed the FreeBSD/Windows break: the intention was to keep
Process::WillResume() and Process::DoResume() "in-sync", but this had the
unfortunate consequence of breaking Process sub-classes which don't override
WillResume().

The safer approach is to keep Process::WillResume() untouched and only
override it in the minidump and core implementations.

patch by lemo

Bug: https://bugs.llvm.org/show_bug.cgi?id=34532

Differential Revision: https://reviews.llvm.org/D37651

llvm-svn: 313655

4 files changed, 34 insertions, 2 deletions

diff --git a/lldb/source/Commands/CommandObjectThread.cpp b/lldb/source/Commands/CommandObjectThread.cpp
index 6a933df43e1..b68aa920b58 100644
--- a/lldb/source/Commands/CommandObjectThread.cpp
+++ b/lldb/source/Commands/CommandObjectThread.cpp
@@ -94,7 +94,7 @@ public:
     bool all_threads = false;
     if (command.GetArgumentCount() == 0) {
       Thread *thread = m_exe_ctx.GetThreadPtr();
-      if (!HandleOneThread(thread->GetID(), result))
+      if (!thread || !HandleOneThread(thread->GetID(), result))
         return false;
       return result.Succeeded();
     } else if (command.GetArgumentCount() == 1) {
@@ -775,6 +775,12 @@ protected:
       else
         error = process->Resume();
 
+      if (!error.Success()) {
+        result.AppendMessage(error.AsCString());
+        result.SetStatus(eReturnStatusFailed);
+        return false;
+      }
+
       // There is a race condition where this thread will return up the call
       // stack to the main command handler
       // and show an (lldb) prompt before HandlePrivateEvent (from
diff --git a/lldb/source/Plugins/Process/elf-core/ProcessElfCore.h b/lldb/source/Plugins/Process/elf-core/ProcessElfCore.h
index dbf7f926f85..64ec5c262f3 100644
--- a/lldb/source/Plugins/Process/elf-core/ProcessElfCore.h
+++ b/lldb/source/Plugins/Process/elf-core/ProcessElfCore.h
@@ -84,11 +84,21 @@ public:
 
   void RefreshStateAfterStop() override;
 
+  lldb_private::Status WillResume() override {
+    lldb_private::Status error;
+    error.SetErrorStringWithFormat(
+        "error: %s does not support resuming processes",
+        GetPluginName().GetCString());
+    return error;
+  }
+
   //------------------------------------------------------------------
   // Process Queries
   //------------------------------------------------------------------
   bool IsAlive() override;
 
+  bool WarnBeforeDetach() const override { return false; }
+
   //------------------------------------------------------------------
   // Process Memory
   //------------------------------------------------------------------
diff --git a/lldb/source/Plugins/Process/minidump/ProcessMinidump.h b/lldb/source/Plugins/Process/minidump/ProcessMinidump.h
index d5c46be9735..4b91d1ba396 100644
--- a/lldb/source/Plugins/Process/minidump/ProcessMinidump.h
+++ b/lldb/source/Plugins/Process/minidump/ProcessMinidump.h
@@ -82,6 +82,14 @@ public:
 
   bool GetProcessInfo(ProcessInstanceInfo &info) override;
 
+  Status WillResume() override {
+    Status error;
+    error.SetErrorStringWithFormat(
+        "error: %s does not support resuming processes",
+        GetPluginName().GetCString());
+    return error;
+  }
+
   MinidumpParser m_minidump_parser;
 
 protected:
diff --git a/lldb/source/Target/Process.cpp b/lldb/source/Target/Process.cpp
index 6cbe289ef26..16f56881dcb 100644
--- a/lldb/source/Target/Process.cpp
+++ b/lldb/source/Target/Process.cpp
@@ -1621,7 +1621,12 @@ Status Process::Resume() {
       log->Printf("Process::Resume: -- TrySetRunning failed, not resuming.");
     return error;
   }
-  return PrivateResume();
+  Status error = PrivateResume();
+  if (!error.Success()) {
+    // Undo running state change
+    m_public_run_lock.SetStopped();
+  }
+  return error;
 }
 
 Status Process::ResumeSynchronous(Stream *stream) {
@@ -1650,6 +1655,9 @@ Status Process::ResumeSynchronous(Stream *stream) {
       error.SetErrorStringWithFormat(
           "process not in stopped state after synchronous resume: %s",
           StateAsCString(state));
+  } else {
+    // Undo running state change
+    m_public_run_lock.SetStopped();
   }
 
   // Undo the hijacking of process events...