[Lldb-commits] [lldb] r197545 - When ProcessMachCore::DoLoadCore() finds *BOTH* a user process dyld and a mach kernel

[Jason Molenda]

Author: jmolenda
Date: Tue Dec 17 19:56:30 2013
New Revision: 197545

URL: http://llvm.org/viewvc/llvm-project?rev=197545&view=rev
Log:
When ProcessMachCore::DoLoadCore() finds *BOTH* a user process dyld and a mach kernel
binary, change to prefer the mach kernel binary by default.

Modified:
    lldb/trunk/source/Plugins/Process/mach-core/ProcessMachCore.cpp

Modified: lldb/trunk/source/Plugins/Process/mach-core/ProcessMachCore.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/mach-core/ProcessMachCore.cpp?rev=197545&r1=197544&r2=197545&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/Process/mach-core/ProcessMachCore.cpp (original)
+++ lldb/trunk/source/Plugins/Process/mach-core/ProcessMachCore.cpp Tue Dec 17 19:56:30 2013
@@ -306,16 +306,28 @@ ProcessMachCore::DoLoadCore ()
         }
     }
 
-    // If we find both a user process dyld and a mach kernel, prefer the
-    // user process dyld.  We may be looking at an lldb debug session were they were debugging
-    // a mach kernel when lldb coredumped.
-    if (m_dyld_addr != LLDB_INVALID_ADDRESS)
+    // If we find both a user process dyld and a mach kernel, we need to pick which one to use.
+    // We're looking at one or two scenarios:
+    //
+    // 1 This is a core of a crashed user process (e.g. a debugger) which has a copy of 
+    //   a kernel in its memory.  lldb crashed while doing kernel debugging, leaving this 
+    //   core file behind.
+    //
+    // 2 This is a kernel core file that happens to have a user-land dyld macho image in
+    //   one of its vm pages.
+    //
+    // #2 is rare, but has happened.  #1 only happens to people debugging the debugger, so
+    // for now, they will be inconvenienced.  FIXME - we should have a ProcessMachCore 
+    // default setting to specify which dynamic loader to use so it can over-ridden without
+    // rebuilding the debugger for those rare occasions where it's needed.
+
+    if (m_mach_kernel_addr != LLDB_INVALID_ADDRESS)
     {
-        m_dyld_plugin_name = DynamicLoaderMacOSXDYLD::GetPluginNameStatic();
+        m_dyld_plugin_name = DynamicLoaderDarwinKernel::GetPluginNameStatic();
     }
-    else if (m_mach_kernel_addr != LLDB_INVALID_ADDRESS)
+    else if (m_dyld_addr != LLDB_INVALID_ADDRESS)
     {
-        m_dyld_plugin_name = DynamicLoaderDarwinKernel::GetPluginNameStatic();
+        m_dyld_plugin_name = DynamicLoaderMacOSXDYLD::GetPluginNameStatic();
     }
 
     // Even if the architecture is set in the target, we need to override