[Lldb-commits] [PATCH] Introduce a new UnwindAssemblySP shared pointer type and use it to fix a memory leak. We are never deleting UnwindAssembly.

[Greg Clayton]

UnwindAssembly::FindPlugin() needs to be modified to return a UnwindAssemblySP and when each UnwindAssembly object is created you need to immediately put it into a shared pointer upon construction. When using enable_shared_from_this() you _must_ create the object by putting it into a shared pointer right away, otherwise when you use "unwinder.shared_from_this()" you will crash as the std::weak_ptr inside the enable_shared_from_this() class won't have been initialized correctly.

On Feb 2, 2014, at 6:00 AM, Jean-Daniel Dupas <devlists at shadowlab.org> wrote:

>  Add enable_shared_from_this to UnwindAssembly for consistency with other sharable classes.
> 
> http://llvm-reviews.chandlerc.com/D2491
> 
> CHANGE SINCE LAST DIFF
>  http://llvm-reviews.chandlerc.com/D2491?vs=6308&id=6821#toc
> 
> Files:
>  include/lldb/Symbol/FuncUnwinders.h
>  include/lldb/Symbol/UnwindTable.h
>  include/lldb/Target/UnwindAssembly.h
>  include/lldb/lldb-forward.h
>  source/Symbol/FuncUnwinders.cpp
>  source/Symbol/UnwindTable.cpp
> 
> Index: include/lldb/Symbol/FuncUnwinders.h
> ===================================================================
> --- include/lldb/Symbol/FuncUnwinders.h
> +++ include/lldb/Symbol/FuncUnwinders.h
> @@ -31,7 +31,7 @@
>     // instructions are finished for migrating breakpoints past the 
>     // stack frame setup instructions when we don't have line table information.
> 
> -    FuncUnwinders (lldb_private::UnwindTable& unwind_table, lldb_private::UnwindAssembly *assembly_profiler, AddressRange range);
> +    FuncUnwinders (lldb_private::UnwindTable& unwind_table, const lldb::UnwindAssemblySP& assembly_profiler, AddressRange range);
> 
>     ~FuncUnwinders ();
> 
> @@ -77,7 +77,7 @@
> 
> private:
>     UnwindTable& m_unwind_table;
> -    UnwindAssembly *m_assembly_profiler;
> +    lldb::UnwindAssemblySP m_assembly_profiler;
>     AddressRange m_range;
> 
>     Mutex m_mutex;
> Index: include/lldb/Symbol/UnwindTable.h
> ===================================================================
> --- include/lldb/Symbol/UnwindTable.h
> +++ include/lldb/Symbol/UnwindTable.h
> @@ -57,7 +57,7 @@
> 
>     bool                m_initialized;  // delay some initialization until ObjectFile is set up
> 
> -    UnwindAssembly* m_assembly_profiler;
> +    lldb::UnwindAssemblySP m_assembly_profiler;
> 
>     DWARFCallFrameInfo* m_eh_frame;
> 
> Index: include/lldb/Target/UnwindAssembly.h
> ===================================================================
> --- include/lldb/Target/UnwindAssembly.h
> +++ include/lldb/Target/UnwindAssembly.h
> @@ -17,6 +17,7 @@
> namespace lldb_private {
> 
> class UnwindAssembly :
> +   public std::enable_shared_from_this<UnwindAssembly>,
>    public PluginInterface
> {
> public:
> Index: include/lldb/lldb-forward.h
> ===================================================================
> --- include/lldb/lldb-forward.h
> +++ include/lldb/lldb-forward.h
> @@ -384,6 +384,7 @@
> #ifndef LLDB_DISABLE_PYTHON
>     typedef std::shared_ptr<lldb_private::ScriptedSyntheticChildren> ScriptedSyntheticChildrenSP;
> #endif
> +    typedef std::shared_ptr<lldb_private::UnwindAssembly> UnwindAssemblySP;
>     typedef std::shared_ptr<lldb_private::UnwindPlan> UnwindPlanSP;
>     typedef lldb_private::SharingPtr<lldb_private::ValueObject> ValueObjectSP;
>     typedef std::shared_ptr<lldb_private::Value> ValueSP;
> Index: source/Symbol/FuncUnwinders.cpp
> ===================================================================
> --- source/Symbol/FuncUnwinders.cpp
> +++ source/Symbol/FuncUnwinders.cpp
> @@ -28,7 +28,7 @@
> FuncUnwinders::FuncUnwinders
> (
>     UnwindTable& unwind_table, 
> -    UnwindAssembly *assembly_profiler, 
> +    const lldb::UnwindAssemblySP& assembly_profiler,
>     AddressRange range
> ) : 
>     m_unwind_table(unwind_table), 
> Index: source/Symbol/UnwindTable.cpp
> ===================================================================
> --- source/Symbol/UnwindTable.cpp
> +++ source/Symbol/UnwindTable.cpp
> @@ -57,7 +57,7 @@
>     ArchSpec arch;
>     if (m_object_file.GetArchitecture (arch))
>     {
> -        m_assembly_profiler = UnwindAssembly::FindPlugin (arch);
> +        m_assembly_profiler.reset(UnwindAssembly::FindPlugin (arch));
>         m_initialized = true;
>     }
> }
> <D2491.2.patch>_______________________________________________
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