// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

// 

#ifndef __unwinder_h__
#define __unwinder_h__


//---------------------------------------------------------------------------------------
//
// OOPStackUnwinder is the abstract base class for unwinding stack frames.  Each of the two 64-bit platforms 
// has its own derived class.  Although the name of this class and its derived classes have changed, they
// are actually borrowed from dbghelp.dll.  (StackWalk64() is built on top of these classes.)  We have ripped
// out everything we don't need such as symbol lookup and various state, and keep just enough code to support 
// VirtualUnwind().  The managed debugging infrastructure can't call RtlVirtualUnwind() because it doesn't 
// work from out-of-processr
//
// Notes:
//    To see what we have changed in the borrowed source, you can diff the original version and our version.
//    For example, on X64, you can diff clr\src\Debug\daccess\amd64\dbs_stack_x64.cpp (the original) and 
//    clr\src\Debug\daccess\amd64\unwinder_amd64.cpp.
//

class OOPStackUnwinder
{
protected:

    // Given a control PC, return the base of the module it is in.  For jitted managed code, this is the 
    // start of the code heap.
    static HRESULT GetModuleBase(      DWORD64  address,
                                 __out PDWORD64 pdwBase);

    // Given a control PC, return the function entry of the functoin it is in.
    static HRESULT GetFunctionEntry(                       DWORD64 address,
                                    __out_ecount(cbBuffer) PVOID   pBuffer,
                                                           DWORD   cbBuffer);
};

#endif // __unwinder_h__