Make the list of synthetic children thread safe

I have been seeing a few crashes where LLDB tries to acquire a cached synthetic child by index, and crashes in the ClusterManager obtaining a shared_ptr for that ValueObject
That kind of crash most often means that I am holding on to a raw pointer to a ValueObject that was let go from the cluster

The main way that could happen is that the synthetic provider is being updated at the same time that some child is being accessed from the previous provider state

This fixes the problem by making the children be stored in a thread-safe map

Fixes rdar://18627964

llvm-svn: 225538

diff --git a/lldb/include/lldb/Core/ThreadSafeSTLMap.h b/lldb/include/lldb/Core/ThreadSafeSTLMap.h
index 703ce48..4235edc 100644 (file)
--- a/lldb/include/lldb/Core/ThreadSafeSTLMap.h
+++ b/lldb/include/lldb/Core/ThreadSafeSTLMap.h
@@ -16,6 +16,7 @@
 
 // Other libraries and framework includes
 // Project includes
+#include "lldb/lldb-defines.h"
 #include "lldb/Host/Mutex.h"
 
 namespace lldb_private {

diff --git a/lldb/include/lldb/Core/ValueObjectSyntheticFilter.h b/lldb/include/lldb/Core/ValueObjectSyntheticFilter.h
index 9846ae6..49c5601 100644 (file)
--- a/lldb/include/lldb/Core/ValueObjectSyntheticFilter.h
+++ b/lldb/include/lldb/Core/ValueObjectSyntheticFilter.h
@@ -12,10 +12,10 @@
 
 // C Includes
 // C++ Includes
-#include <map>
 #include <vector>
 // Other libraries and framework includes
 // Project includes
+#include "lldb/Core/ThreadSafeSTLMap.h"
 #include "lldb/Core/ValueObject.h"
 
 namespace lldb_private {
@@ -154,8 +154,8 @@ protected:
     lldb::SyntheticChildrenSP m_synth_sp;
     std::unique_ptr<SyntheticChildrenFrontEnd> m_synth_filter_ap;
     
-    typedef std::map<uint32_t, ValueObject*> ByIndexMap;
-    typedef std::map<const char*, uint32_t> NameToIndexMap;
+    typedef ThreadSafeSTLMap<uint32_t, ValueObject*> ByIndexMap;
+    typedef ThreadSafeSTLMap<const char*, uint32_t> NameToIndexMap;
     
     typedef ByIndexMap::iterator ByIndexIterator;
     typedef NameToIndexMap::iterator NameToIndexIterator;

diff --git a/lldb/source/Core/ValueObjectSyntheticFilter.cpp b/lldb/source/Core/ValueObjectSyntheticFilter.cpp
index 9bdf689..dafe73a 100644 (file)
--- a/lldb/source/Core/ValueObjectSyntheticFilter.cpp
+++ b/lldb/source/Core/ValueObjectSyntheticFilter.cpp
@@ -182,8 +182,8 @@ ValueObjectSynthetic::UpdateValue ()
     if (m_synth_filter_ap->Update() == false)
     {
         // filter said that cached values are stale
-        m_children_byindex.clear();
-        m_name_toindex.clear();
+        m_children_byindex.Clear();
+        m_name_toindex.Clear();
         // usually, an object's value can change but this does not alter its children count
         // for a synthetic VO that might indeed happen, so we need to tell the upper echelons
         // that they need to come back to us asking for children
@@ -216,23 +216,22 @@ ValueObjectSynthetic::GetChildAtIndex (size_t idx, bool can_create)
 {
     UpdateValueIfNeeded();
     
-    ByIndexIterator iter = m_children_byindex.find(idx);
-    
-    if (iter == m_children_byindex.end())
+    ValueObject *valobj;
+    if (m_children_byindex.GetValueForKey(idx, valobj) == false)
     {
         if (can_create && m_synth_filter_ap.get() != NULL)
         {
             lldb::ValueObjectSP synth_guy = m_synth_filter_ap->GetChildAtIndex (idx);
             if (!synth_guy)
                 return synth_guy;
-            m_children_byindex[idx]= synth_guy.get();
+            m_children_byindex.SetValueForKey(idx, synth_guy.get());
             return synth_guy;
         }
         else
             return lldb::ValueObjectSP();
     }
     else
-        return iter->second->GetSP();
+        return valobj->GetSP();
 }
 
 lldb::ValueObjectSP
@@ -253,20 +252,21 @@ ValueObjectSynthetic::GetIndexOfChildWithName (const ConstString &name)
 {
     UpdateValueIfNeeded();
     
-    NameToIndexIterator iter = m_name_toindex.find(name.GetCString());
+    uint32_t found_index = UINT32_MAX;
+    bool did_find = m_name_toindex.GetValueForKey(name.GetCString(), found_index);
     
-    if (iter == m_name_toindex.end() && m_synth_filter_ap.get() != NULL)
+    if (!did_find && m_synth_filter_ap.get() != NULL)
     {
         uint32_t index = m_synth_filter_ap->GetIndexOfChildWithName (name);
         if (index == UINT32_MAX)
             return index;
-        m_name_toindex[name.GetCString()] = index;
+        m_name_toindex.SetValueForKey(name.GetCString(), index);
         return index;
     }
-    else if (iter == m_name_toindex.end() && m_synth_filter_ap.get() == NULL)
+    else if (!did_find && m_synth_filter_ap.get() == NULL)
         return UINT32_MAX;
     else /*if (iter != m_name_toindex.end())*/
-        return iter->second;
+        return found_index;
 }
 
 bool