MallocDoubleFreeFinder.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Containers/Map.h"
#include "HAL/MallocCallstackHandler.h"
#include "HAL/Platform.h"
 
class FMalloc;
class FOutputDevice;
class UWorld;
 
class FMallocDoubleFreeFinder final : public FMallocCallstackHandler
{
public:
    FMallocDoubleFreeFinder(FMalloc* InMalloc);
 
    /**
     * Handles any commands passed in on the command line
     */
    virtual bool Exec(UWorld* InWorld, const TCHAR* Cmd, FOutputDevice& Ar) override;
 
    /**
     * If you get an allocation/memory error outside of the allocator you can call this directly
     * It will dump a callstack of the last allocator free most likely to have caused the problem to the log, if you have symbols loaded
     * Might be useful to pass an access violation ptr to this!
     */
    void TrackSpecial(void* Ptr);
 
    virtual void Init();
 
    static FMalloc* OverrideIfEnabled(FMalloc*InUsedAlloc);
 
protected:
    virtual void TrackMalloc(void* Ptr, uint32 Size, int32 CallStackIndex);
    virtual void TrackFree(void* Ptr, uint32 OldSize, int32 CallStackIndex);
 
    struct TrackedAllocationData
    {
        SIZE_T Size;
        int32 CallStackIndex;
        TrackedAllocationData() :
            Size(0),
            CallStackIndex(-1)
        {
        };
        TrackedAllocationData(SIZE_T InRequestedSize, int32 InCallStackIndex)
        {
            Size = InRequestedSize;
            CallStackIndex = InCallStackIndex;
        };
        ~TrackedAllocationData()
        {
            Size = 0;
            CallStackIndex = -1;
        };
    };
    TMap<const void* const, TrackedAllocationData> TrackedCurrentAllocations;   // Pointer as a key to a call stack for all the current allocations we known about
    TMap<const void* const, TrackedAllocationData> TrackedFreeAllocations;      // Pointer as a key to a call stack for all allocations that have been freed
};
 
extern FMallocDoubleFreeFinder* GMallocDoubleFreeFinder;
extern bool GMallocDoubleFreeFinderEnabled;