Small refinement on the memory segment support in core files that

Greg added in r272276 -- when working with a non-user-process mach-o
core file, force the permissions to readable + executable, else the
unwinder can stop backtracing early if it gets a pc value in a segment
that it thinks is non-executable.
<rdar://problem/27138456> 
<rdar://problem/27462904> 

llvm-svn: 277065

1 files changed, 17 insertions, 0 deletions

diff --git a/lldb/source/Plugins/Process/mach-core/ProcessMachCore.cpp b/lldb/source/Plugins/Process/mach-core/ProcessMachCore.cpp
index 6bf198ca2f3..d2f50ba6c54 100644
--- a/lldb/source/Plugins/Process/mach-core/ProcessMachCore.cpp
+++ b/lldb/source/Plugins/Process/mach-core/ProcessMachCore.cpp
@@ -418,6 +418,23 @@ ProcessMachCore::DoLoadCore ()
         }
     }
 
+    if (m_dyld_plugin_name != DynamicLoaderMacOSXDYLD::GetPluginNameStatic())
+    {
+        // For non-user process core files, the permissions on the core file segments are usually
+        // meaningless, they may be just "read", because we're dealing with kernel coredumps or
+        // early startup coredumps and the dumper is grabbing pages of memory without knowing
+        // what they are.  If they aren't marked as "exeuctable", that can break the unwinder
+        // which will check a pc value to see if it is in an executable segment and stop the
+        // backtrace early if it is not ("executable" and "unknown" would both be fine, but 
+        // "not executable" will break the unwinder).
+        size_t core_range_infos_size = m_core_range_infos.GetSize();
+        for (size_t i = 0; i < core_range_infos_size; i++)
+        {
+            VMRangeToPermissions::Entry *ent = m_core_range_infos.GetMutableEntryAtIndex (i);
+            ent->data = lldb::ePermissionsReadable | lldb::ePermissionsExecutable;
+        }
+    }
+
     // Even if the architecture is set in the target, we need to override
     // it to match the core file which is always single arch.
     ArchSpec arch (m_core_module_sp->GetArchitecture());