Lock the access to the BreakpointLocationCollection.

I was investigating an odd crash in lldb when the breakpoint site
goes to bump the hit counts of the locations it implements.  I noticed
that the BreakpointLocationCollection wasn't locking itself for access and
modification.  I don't see how that can cause the crash I'm seeing, but still
this is the right thing to do...

<rdar://problem/25178205>

llvm-svn: 270939

2 files changed, 13 insertions, 2 deletions

diff --git a/lldb/include/lldb/Breakpoint/BreakpointLocationCollection.h b/lldb/include/lldb/Breakpoint/BreakpointLocationCollection.h
index 004f8395122..1a016544fa4 100644
--- a/lldb/include/lldb/Breakpoint/BreakpointLocationCollection.h
+++ b/lldb/include/lldb/Breakpoint/BreakpointLocationCollection.h
@@ -13,6 +13,8 @@
 // C Includes
 // C++ Includes
 #include <vector>
+#include <mutex>
+
 // Other libraries and framework includes
 // Project includes
 #include "lldb/lldb-private.h"
@@ -201,7 +203,8 @@ private:
     collection::const_iterator
     GetIDPairConstIterator(lldb::break_id_t break_id, lldb::break_id_t break_loc_id) const;
 
-    collection m_break_loc_collection;
+    collection     m_break_loc_collection;
+    mutable std::mutex  m_collection_mutex;
 
 public:
     typedef AdaptedIterable<collection, lldb::BreakpointLocationSP, vector_adapter> BreakpointLocationCollectionIterable;
diff --git a/lldb/source/Breakpoint/BreakpointLocationCollection.cpp b/lldb/source/Breakpoint/BreakpointLocationCollection.cpp
index 5b6e746f911..52698b2f15b 100644
--- a/lldb/source/Breakpoint/BreakpointLocationCollection.cpp
+++ b/lldb/source/Breakpoint/BreakpointLocationCollection.cpp
@@ -26,7 +26,8 @@ using namespace lldb_private;
 // BreakpointLocationCollection constructor
 //----------------------------------------------------------------------
 BreakpointLocationCollection::BreakpointLocationCollection() :
-    m_break_loc_collection()
+    m_break_loc_collection(),
+    m_collection_mutex()
 {
 }
 
@@ -40,6 +41,7 @@ BreakpointLocationCollection::~BreakpointLocationCollection()
 void
 BreakpointLocationCollection::Add(const BreakpointLocationSP &bp_loc)
 {
+    std::lock_guard<std::mutex> guard(m_collection_mutex);
     BreakpointLocationSP old_bp_loc = FindByIDPair (bp_loc->GetBreakpoint().GetID(), bp_loc->GetID());
     if (!old_bp_loc.get())
         m_break_loc_collection.push_back(bp_loc);
@@ -48,6 +50,7 @@ BreakpointLocationCollection::Add(const BreakpointLocationSP &bp_loc)
 bool
 BreakpointLocationCollection::Remove (lldb::break_id_t bp_id, lldb::break_id_t bp_loc_id)
 {
+    std::lock_guard<std::mutex> guard(m_collection_mutex);
     collection::iterator pos = GetIDPairIterator(bp_id, bp_loc_id);    // Predicate
     if (pos != m_break_loc_collection.end())
     {
@@ -117,6 +120,7 @@ BreakpointLocationCollection::FindByIDPair (lldb::break_id_t break_id, lldb::bre
 BreakpointLocationSP
 BreakpointLocationCollection::GetByIndex (size_t i)
 {
+    std::lock_guard<std::mutex> guard(m_collection_mutex);
     BreakpointLocationSP stop_sp;
     if (i < m_break_loc_collection.size())
         stop_sp = m_break_loc_collection[i];
@@ -127,6 +131,7 @@ BreakpointLocationCollection::GetByIndex (size_t i)
 const BreakpointLocationSP
 BreakpointLocationCollection::GetByIndex (size_t i) const
 {
+    std::lock_guard<std::mutex> guard(m_collection_mutex);
     BreakpointLocationSP stop_sp;
     if (i < m_break_loc_collection.size())
         stop_sp = m_break_loc_collection[i];
@@ -156,6 +161,7 @@ BreakpointLocationCollection::ShouldStop (StoppointCallbackContext *context)
 bool 
 BreakpointLocationCollection::ValidForThisThread (Thread *thread)
 {
+    std::lock_guard<std::mutex> guard(m_collection_mutex);
     collection::iterator pos,
         begin = m_break_loc_collection.begin(),
         end = m_break_loc_collection.end();
@@ -171,6 +177,7 @@ BreakpointLocationCollection::ValidForThisThread (Thread *thread)
 bool 
 BreakpointLocationCollection::IsInternal () const
 {
+    std::lock_guard<std::mutex> guard(m_collection_mutex);
     collection::const_iterator pos,
         begin = m_break_loc_collection.begin(),
         end = m_break_loc_collection.end();
@@ -191,6 +198,7 @@ BreakpointLocationCollection::IsInternal () const
 void
 BreakpointLocationCollection::GetDescription (Stream *s, lldb::DescriptionLevel level)
 {
+    std::lock_guard<std::mutex> guard(m_collection_mutex);
     collection::iterator pos,
         begin = m_break_loc_collection.begin(),
         end = m_break_loc_collection.end();