[lldb-dev] Invalid iterator dereference in TypeMap::ForEach when it's invoked with TypeMaptoList callback

[Greg Clayton via lldb-dev]

I fixed this:

% svn commit
Sending        include/lldb/Symbol/TypeMap.h
Sending        source/Symbol/SymbolContext.cpp
Sending        source/Symbol/TypeMap.cpp
Transmitting file data ...
Committed revision 253618.


> On Nov 18, 2015, at 12:54 AM, Ravitheja Addepally via lldb-dev <lldb-dev at lists.llvm.org> wrote:
> 
> Hello,
>      Pavel- my question is how do we solve it ? should Mikhail log a bug ? for this issue 
> 
> BR,
> A Ravi Theja
> 
> On Tue, Nov 17, 2015 at 10:42 AM, Ravitheja Addepally <ravithejawork at gmail.com> wrote:
> Hello,
> 
>                 Yeah you are right Mikhail, thanks for pointing it out, I must ask, is there any bug already logged for this issue ?
> 
> Ravi
> 
> 
> On Mon, Nov 16, 2015 at 5:24 PM, Mikhail Filimonov via lldb-dev <lldb-dev at lists.llvm.org> wrote:
> Hi guys and thank you for the excellent community project!
> 
>  
> 
> Recently I’ve stumbled on a pesky, but trivial Invalid iterator dereference bug in SymbolContext and TypeMap implementations at revisions
> 
> https://github.com/llvm-mirror/lldb/blob/e528da256d14ecac7df858462b44dca931879509/source/Symbol/SymbolContext.cpp#L823
> 
> and
> 
> https://github.com/llvm-mirror/lldb/blob/5ac1fc5bc961688505334395598a2bb174eabd3b/source/Symbol/TypeMap.cpp#L172
> 
>  
> 
> From the code below it is obvious that TypeMap::ForEach calls the pre-increment operator on m_types iterator right after it has been invalidated by m_types.erase
> 
>  
> 
> SymbolContext::SortTypeList(TypeMap &type_map, TypeList &type_list ) const
> 
> {
> 
>         TypeMaptoList callbackM2L (type_map, type_list);
> 
>         type_map.ForEach(callbackM2L);
> 
>                 return ;
> 
> }
> 
>  
> 
> void
> 
> TypeMap::ForEach (std::function <bool(lldb::TypeSP &type_sp)> const &callback)
> 
> {
> 
>     for (auto pos = m_types.begin(), end = m_types.end(); pos != end; ++pos)
> 
>     {
> 
>         if (!callback(pos->second))
> 
>             break;
> 
>     }
> 
> }
> 
>  
> 
> bool
> 
> TypeMap::RemoveTypeWithUID (user_id_t uid)
> 
> {
> 
>     iterator pos = m_types.find(uid);
> 
>    
> 
>     if (pos != m_types.end())
> 
>     {
> 
>         m_types.erase(pos);
> 
>         return true;
> 
>     }
> 
>     return false;
> 
> }
> 
>  
> 
> class TypeMaptoList
> 
> {
> 
> public:
> 
>     TypeMaptoList(TypeMap &typem, TypeList &typel) :
> 
>         type_map(typem),type_list(typel)
> 
>     {
> 
>     }
> 
>  
> 
>     bool
> 
>     operator() (const lldb::TypeSP& type)
> 
>     {
> 
>         if(type)
> 
>         {
> 
>             type_list.Insert(type);
> 
>             type_map.RemoveTypeWithUID(type->GetID());
> 
>             if (type_map.Empty())
> 
>                 return false;
> 
>         }
> 
>         return true;
> 
>     }
> 
>  
> 
> private:
> 
>     TypeMap &type_map;
> 
>     TypeList &type_list;
> 
> };
> 
>  
> 
> Regards,
> 
> Mikhail Filimonov
> 
>  
> 
>  
> 
>  
> 
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