Change the /proc/<pid>/maps to not assert on incorrect input

[tberghammer]

Summary

Change the /proc/<pid>/maps to not assert on incorrect input

If LLDB reads some incorrect input form /proc/<pid>/maps then it
should report an error instead of assert-ing as we don't want to
crash in case of an incorrect maps file.

[labath]

Given that this "file" comes straight from the kernel, i don't think asserting here is necessarily a bad thing, but I don't really care either way...

lldb/trunk/source/Plugins/Process/Linux/NativeProcessLinux.cpp

ParseMemoryRegionInfoFromProcMapsLine (const std::string &maps_line, MemoryRegionInfo &memory_region_info)
     // Parse out each permission entry.
     if (line_extractor.GetBytesLeft () < 4)
         return Error ("malformed /proc/{pid}/maps entry, missing some portion of permissions");
 
     // Handle read permission.
     const char read_perm_char = line_extractor.GetChar ();
     if (read_perm_char == 'r')
         memory_region_info.SetReadable (MemoryRegionInfo::OptionalBool::eYes);
-    else
-    {
-        assert ( (read_perm_char == '-') && "unexpected /proc/{pid}/maps read permission char" );
+    else if (read_perm_char == '-')
         memory_region_info.SetReadable (MemoryRegionInfo::OptionalBool::eNo);
-    }
+    else
+        return Error ("unexpected /proc/{pid}/maps read permission char");
 
     // Handle write permission.
     const char write_perm_char = line_extractor.GetChar ();
     if (write_perm_char == 'w')
         memory_region_info.SetWritable (MemoryRegionInfo::OptionalBool::eYes);
-    else
-    {
-        assert ( (write_perm_char == '-') && "unexpected /proc/{pid}/maps write permission char" );
+    else if (write_perm_char == '-')
         memory_region_info.SetWritable (MemoryRegionInfo::OptionalBool::eNo);
-    }
+    else
+        return Error ("unexpected /proc/{pid}/maps write permission char");
 
     // Handle execute permission.
     const char exec_perm_char = line_extractor.GetChar ();
     if (exec_perm_char == 'x')
         memory_region_info.SetExecutable (MemoryRegionInfo::OptionalBool::eYes);
-    else
-    {
-        assert ( (exec_perm_char == '-') && "unexpected /proc/{pid}/maps exec permission char" );
+    else if (exec_perm_char == '-')
         memory_region_info.SetExecutable (MemoryRegionInfo::OptionalBool::eNo);
-    }
+    else
+        return Error ("unexpected /proc/{pid}/maps exec permission char");
 
     return Error ();
 }
 
 Error
 NativeProcessLinux::GetMemoryRegionInfo (lldb::addr_t load_addr, MemoryRegionInfo &range_info)
 {
     // FIXME review that the final memory region returned extends to the end of the virtual address space,