[Lldb-commits] [lldb] r211241 - Add a lock in the UnwindTable class so two Targets won't try

[Jason Molenda]

Author: jmolenda
Date: Wed Jun 18 18:32:53 2014
New Revision: 211241

URL: http://llvm.org/viewvc/llvm-project?rev=211241&view=rev
Log:
Add a lock in the UnwindTable class so two Targets won't try
to modify the same UnwindTable object simultaneously.  Fix
HistoryThread and HistoryUnwind's mutex lock acqusition to
retain the lock for the duration of the operation instead of
releasing the temporary immediately.
<rdar://problem/17055023>

Modified:
    lldb/trunk/include/lldb/Symbol/UnwindTable.h
    lldb/trunk/source/Plugins/Process/Utility/HistoryThread.cpp
    lldb/trunk/source/Plugins/Process/Utility/HistoryUnwind.cpp
    lldb/trunk/source/Symbol/UnwindTable.cpp

Modified: lldb/trunk/include/lldb/Symbol/UnwindTable.h
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/include/lldb/Symbol/UnwindTable.h?rev=211241&r1=211240&r2=211241&view=diff
==============================================================================
--- lldb/trunk/include/lldb/Symbol/UnwindTable.h (original)
+++ lldb/trunk/include/lldb/Symbol/UnwindTable.h Wed Jun 18 18:32:53 2014
@@ -14,6 +14,7 @@
 #include <map>
 
 #include "lldb/lldb-private.h" 
+#include "lldb/Host/Mutex.h"
 
 namespace lldb_private {
 
@@ -59,6 +60,7 @@ private:
     collection          m_unwinds;
 
     bool                m_initialized;  // delay some initialization until ObjectFile is set up
+    Mutex               m_mutex;
 
     DWARFCallFrameInfo* m_eh_frame;
     

Modified: lldb/trunk/source/Plugins/Process/Utility/HistoryThread.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/Utility/HistoryThread.cpp?rev=211241&r1=211240&r2=211241&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/Process/Utility/HistoryThread.cpp (original)
+++ lldb/trunk/source/Plugins/Process/Utility/HistoryThread.cpp Wed Jun 18 18:32:53 2014
@@ -78,7 +78,7 @@ HistoryThread::CreateRegisterContextForF
 lldb::StackFrameListSP
 HistoryThread::GetStackFrameList ()
 {
-    Mutex::Locker (m_framelist_mutex);
+    Mutex::Locker locker(m_framelist_mutex);
     if (m_framelist.get() == NULL)
     {
         m_framelist.reset (new StackFrameList (*this, StackFrameListSP(), true));

Modified: lldb/trunk/source/Plugins/Process/Utility/HistoryUnwind.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/Utility/HistoryUnwind.cpp?rev=211241&r1=211240&r2=211241&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/Process/Utility/HistoryUnwind.cpp (original)
+++ lldb/trunk/source/Plugins/Process/Utility/HistoryUnwind.cpp Wed Jun 18 18:32:53 2014
@@ -66,7 +66,7 @@ HistoryUnwind::DoCreateRegisterContextFo
 bool
 HistoryUnwind::DoGetFrameInfoAtIndex (uint32_t frame_idx, lldb::addr_t& cfa, lldb::addr_t& pc)
 {
-    Mutex::Locker (m_unwind_mutex);
+    Mutex::Locker locker(m_unwind_mutex);
     if (frame_idx < m_pcs.size())
     {
         cfa = frame_idx;

Modified: lldb/trunk/source/Symbol/UnwindTable.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Symbol/UnwindTable.cpp?rev=211241&r1=211240&r2=211241&view=diff
==============================================================================
--- lldb/trunk/source/Symbol/UnwindTable.cpp (original)
+++ lldb/trunk/source/Symbol/UnwindTable.cpp Wed Jun 18 18:32:53 2014
@@ -29,6 +29,7 @@ UnwindTable::UnwindTable (ObjectFile& ob
     m_object_file (objfile), 
     m_unwinds (),
     m_initialized (false),
+    m_mutex (),
     m_eh_frame (nullptr)
 {
 }
@@ -42,6 +43,11 @@ UnwindTable::Initialize ()
     if (m_initialized)
         return;
 
+    Mutex::Locker locker(m_mutex);
+
+    if (m_initialized) // check again once we've acquired the lock
+        return;
+
     SectionList* sl = m_object_file.GetSectionList ();
     if (sl)
     {
@@ -68,6 +74,8 @@ UnwindTable::GetFuncUnwindersContainingA
 
     Initialize();
 
+    Mutex::Locker locker(m_mutex);
+
     // There is an UnwindTable per object file, so we can safely use file handles
     addr_t file_addr = addr.GetFileAddress();
     iterator end = m_unwinds.end ();
@@ -128,6 +136,7 @@ UnwindTable::GetUncachedFuncUnwindersCon
 void
 UnwindTable::Dump (Stream &s)
 {
+    Mutex::Locker locker(m_mutex);
     s.Printf("UnwindTable for '%s':\n", m_object_file.GetFileSpec().GetPath().c_str());
     const_iterator begin = m_unwinds.begin();
     const_iterator end = m_unwinds.end();