¿Cuál es el diseño de VTable y la ubicación del puntero VTable en objetos C++ en GCC 3.xy 4.x?

Estoy buscando detalles de la estructura de la tabla VT, orden y contenido, y la ubicación de los punteros vtable dentro de los objetos.¿Cuál es el diseño de VTable y la ubicación del puntero VTable en objetos C++ en GCC 3.xy 4.x?

Idealmente, esto cubrirá la herencia única, la herencia múltiple y la herencia virtual.

referencias a la documentación externa también serían apreciados

Documentación de diseño clase GCC 4.0x es here y el Itanium, y más ampliamente GNU, los documentos de diseño de ABI son here.

Fuente

2008-09-16 grrussel

Esto probablemente se describe en [C++ ABI] (http://www.codesourcery.com/public/cxx-abi/). Por ejemplo, [C++ VTable examples] (http://mentorembedded.github.com/cxx-abi/abi-examples.html). – squadette

¿Has probado la opción '-fdump-class-hierarchy' de gcc? – jaor

¡El primer enlace está muerto! D: – minmaxavg

-4

La mayoría de las implementaciones del compilador que he visto simplemente "incrustan" el objeto base en el objeto derivado. Se vuelve irrelevante donde se guarda el vtable porque el desplazamiento relativo en el objeto simplemente se agregará en el momento de la compilación a medida que se evalúan las referencias.

La herencia múltiple y virtual es más complicada y puede requerir un desplazamiento diferente según lo que se está accediendo.

recomiendo encarecidamente la lectura de este artículo sobre el Proyecto de Código: The Impossibly Fast C++ Delegates

Es brillantemente da un panorama general de cómo los diferentes compiladores manejar varios aspectos de la herencia. Lectura fantástica si le interesa el funcionamiento de bajo nivel de diferentes compiladores.

Editar: He vinculado el artículo equivocado por allí. Corregido

Fuente

2014-09-04 20:54:59 GlGuru

"Se vuelve irrelevante donde se guarda el vtable" Parece _muy_ relevante. La mitad de la pregunta fue específicamente preguntando dónde se guarda para los diferentes tipos de herencia. Decir 'no importa' para uno y 'es complicado' para el resto no es una respuesta. Además, te perdiste la otra mitad de la pregunta, preguntando cómo están estructurados los vtables. –

Además, no veo cómo el artículo explica cómo los compiladores manejan la herencia.Todo lo que habla es de delegados, que son un concepto ortogonal. –

Una tabla virtual generalmente se trata como una matriz de indicadores de función, aunque los compiladores pueden poner punteros de datos (en escenarios MI y VI, o tipos de letra), enteros (para reparaciones) o elementos centinela (como NULL punteros) en él también. El diseño generalmente es específico del compilador (o específico de ABI donde varios compiladores de C++ comparten un ABI), pero estable siempre que las clases compiladas tengan interfaces estables (de lo contrario tendrías que recompilar tu código todo el tiempo, y eso es un arrastre) . También hay tablas adicionales que se necesitan para manejar casos de esquina que implican herencia virtual y múltiple, y para asegurarse de que las llamadas virtuales durante la construcción de clase derivada se comporten como el Estándar dice que deberían en esas circunstancias (eso es lo que los VTT y tablas de construcción en el el resultado a continuación es para).

En cuanto al caso específico de GCC 4.x: el interruptor -fdump-class-hierarchy de hecho actúa como se describe (y algunos más). He comprobado en Coliru utilizando el código de ejemplo a continuación:

struct Base 
{ 
    virtual ~Base() {} 
    virtual void f() = 0; 
}; 

struct OtherBase 
{ 
    virtual ~OtherBase() {} 
    virtual void g() {} 
}; 

struct Derived: public Base 
{ 
    virtual ~Derived() {} 
    virtual void f() {} 
}; 

struct MultiplyDerived: public Base, public OtherBase 
{ 
    virtual ~MultiplyDerived() {} 
    virtual void f() {} 
    virtual void g() {} 
}; 

struct OtherDerived: public Base 
{ 
    virtual ~OtherDerived() {} 
    virtual void f() {} 
}; 

struct DiamondDerived: public Derived, public OtherDerived 
{ 
    virtual ~DiamondDerived() {} 
    virtual void f() {} 
}; 

struct VirtuallyDerived: virtual public Base 
{ 
    virtual ~VirtuallyDerived() {} 
    virtual void f() {} 
}; 

struct OtherVirtuallyDerived: virtual public Base 
{ 
    virtual ~OtherVirtuallyDerived() {} 
    virtual void f() {} 
}; 

struct VirtuallyDiamondDerived: public VirtuallyDerived, public OtherVirtuallyDerived 
{ 
    virtual ~VirtuallyDiamondDerived() {} 
    virtual void f() {} 
}; 

struct DoublyVirtuallyDiamondDerived: virtual public VirtuallyDerived, virtual public OtherVirtuallyDerived 
{ 
    virtual ~DoublyVirtuallyDiamondDerived() {} 
    virtual void f() {} 
}; 

struct MixedVirtuallyDerived: virtual public Base, public OtherBase 
{ 
    virtual ~MixedVirtuallyDerived() {} 
}; 

struct MixedVirtuallyDiamondDerived: public VirtuallyDerived, public MixedVirtuallyDerived 
{ 
    virtual ~MixedVirtuallyDiamondDerived() {} 
    virtual void f() {} 
    virtual void g() {} 
}; 

struct VirtuallyMultiplyDerived: virtual public Base, virtual public OtherBase 
{ 
    virtual ~VirtuallyMultiplyDerived() {} 
}; 

struct OtherVirtuallyMultiplyDerived: virtual public Base, virtual public OtherBase 
{ 
    virtual ~OtherVirtuallyMultiplyDerived() {} 
}; 

struct MultiplyVirtuallyDiamondDerived: public VirtuallyMultiplyDerived, public OtherVirtuallyMultiplyDerived 
{ 
    virtual ~MultiplyVirtuallyDiamondDerived() {} 
    virtual void f() {} 
    virtual void g() {} 
};

y recibido de G ++ (guía nombre revuelto: TI'S están typeinfos, televisión es vtables, y Th de y Tv'S están thunks utilizados para hacer llamadas virtuales correctas en la presencia de herencia múltiple y/o virtual):

 
Vtable for Base 

Base::_ZTV4Base: 5u entries 

0  (int (*)(...))0 

8  (int (*)(...))(& _ZTI4Base) 

16 0u 

24 0u 

32 (int (*)(...))__cxa_pure_virtual 


Class Base 

    size=8 align=8 

    base size=8 base align=8 

Base (0x0x7fd42c0355a0) 0 nearly-empty 

    vptr=((& Base::_ZTV4Base) + 16u) 


Vtable for OtherBase 

OtherBase::_ZTV9OtherBase: 5u entries 

0  (int (*)(...))0 

8  (int (*)(...))(& _ZTI9OtherBase) 

16 (int (*)(...))OtherBase::~OtherBase 

24 (int (*)(...))OtherBase::~OtherBase 

32 (int (*)(...))OtherBase::g 


Class OtherBase 

    size=8 align=8 

    base size=8 base align=8 

OtherBase (0x0x7fd42c035600) 0 nearly-empty 

    vptr=((& OtherBase::_ZTV9OtherBase) + 16u) 


Vtable for Derived 

Derived::_ZTV7Derived: 5u entries 

0  (int (*)(...))0 

8  (int (*)(...))(& _ZTI7Derived) 

16 (int (*)(...))Derived::~Derived 

24 (int (*)(...))Derived::~Derived 

32 (int (*)(...))Derived::f 


Class Derived 

    size=8 align=8 

    base size=8 base align=8 

Derived (0x0x7fd42c02d138) 0 nearly-empty 

    vptr=((& Derived::_ZTV7Derived) + 16u) 

    Base (0x0x7fd42c035660) 0 nearly-empty 

     primary-for Derived (0x0x7fd42c02d138) 


Vtable for MultiplyDerived 

MultiplyDerived::_ZTV15MultiplyDerived: 11u entries 

0  (int (*)(...))0 

8  (int (*)(...))(& _ZTI15MultiplyDerived) 

16 (int (*)(...))MultiplyDerived::~MultiplyDerived 

24 (int (*)(...))MultiplyDerived::~MultiplyDerived 

32 (int (*)(...))MultiplyDerived::f 

40 (int (*)(...))MultiplyDerived::g 

48 (int (*)(...))-8 

56 (int (*)(...))(& _ZTI15MultiplyDerived) 

64 (int (*)(...))MultiplyDerived::_ZThn8_N15MultiplyDerivedD1Ev 

72 (int (*)(...))MultiplyDerived::_ZThn8_N15MultiplyDerivedD0Ev 

80 (int (*)(...))MultiplyDerived::_ZThn8_N15MultiplyDerived1gEv 


Class MultiplyDerived 

    size=16 align=8 

    base size=16 base align=8 

MultiplyDerived (0x0x7fd42c04aaf0) 0 

    vptr=((& MultiplyDerived::_ZTV15MultiplyDerived) + 16u) 

    Base (0x0x7fd42c0356c0) 0 nearly-empty 

     primary-for MultiplyDerived (0x0x7fd42c04aaf0) 

    OtherBase (0x0x7fd42c035720) 8 nearly-empty 

     vptr=((& MultiplyDerived::_ZTV15MultiplyDerived) + 64u) 


Vtable for OtherDerived 

OtherDerived::_ZTV12OtherDerived: 5u entries 

0  (int (*)(...))0 

8  (int (*)(...))(& _ZTI12OtherDerived) 

16 (int (*)(...))OtherDerived::~OtherDerived 

24 (int (*)(...))OtherDerived::~OtherDerived 

32 (int (*)(...))OtherDerived::f 


Class OtherDerived 

    size=8 align=8 

    base size=8 base align=8 

OtherDerived (0x0x7fd42c02d1a0) 0 nearly-empty 

    vptr=((& OtherDerived::_ZTV12OtherDerived) + 16u) 

    Base (0x0x7fd42c035780) 0 nearly-empty 

     primary-for OtherDerived (0x0x7fd42c02d1a0) 


Vtable for DiamondDerived 

DiamondDerived::_ZTV14DiamondDerived: 10u entries 

0  (int (*)(...))0 

8  (int (*)(...))(& _ZTI14DiamondDerived) 

16 (int (*)(...))DiamondDerived::~DiamondDerived 

24 (int (*)(...))DiamondDerived::~DiamondDerived 

32 (int (*)(...))DiamondDerived::f 

40 (int (*)(...))-8 

48 (int (*)(...))(& _ZTI14DiamondDerived) 

56 (int (*)(...))DiamondDerived::_ZThn8_N14DiamondDerivedD1Ev 

64 (int (*)(...))DiamondDerived::_ZThn8_N14DiamondDerivedD0Ev 

72 (int (*)(...))DiamondDerived::_ZThn8_N14DiamondDerived1fEv 


Class DiamondDerived 

    size=16 align=8 

    base size=16 base align=8 

DiamondDerived (0x0x7fd42c0625b0) 0 

    vptr=((& DiamondDerived::_ZTV14DiamondDerived) + 16u) 

    Derived (0x0x7fd42c02d208) 0 nearly-empty 

     primary-for DiamondDerived (0x0x7fd42c0625b0) 

    Base (0x0x7fd42c0357e0) 0 nearly-empty 

     primary-for Derived (0x0x7fd42c02d208) 

    OtherDerived (0x0x7fd42c02d270) 8 nearly-empty 

     vptr=((& DiamondDerived::_ZTV14DiamondDerived) + 56u) 

    Base (0x0x7fd42c035840) 8 nearly-empty 

     primary-for OtherDerived (0x0x7fd42c02d270) 


Vtable for VirtuallyDerived 

VirtuallyDerived::_ZTV16VirtuallyDerived: 8u entries 

0  0u 

8  0u 

16 0u 

24 (int (*)(...))0 

32 (int (*)(...))(& _ZTI16VirtuallyDerived) 

40 (int (*)(...))VirtuallyDerived::~VirtuallyDerived 

48 (int (*)(...))VirtuallyDerived::~VirtuallyDerived 

56 (int (*)(...))VirtuallyDerived::f 


VTT for VirtuallyDerived 

VirtuallyDerived::_ZTT16VirtuallyDerived: 2u entries 

0  ((& VirtuallyDerived::_ZTV16VirtuallyDerived) + 40u) 

8  ((& VirtuallyDerived::_ZTV16VirtuallyDerived) + 40u) 


Class VirtuallyDerived 

    size=8 align=8 

    base size=8 base align=8 

VirtuallyDerived (0x0x7fd42c02d2d8) 0 nearly-empty 

    vptridx=0u vptr=((& VirtuallyDerived::_ZTV16VirtuallyDerived) + 40u) 

    Base (0x0x7fd42c0358a0) 0 nearly-empty virtual 

     primary-for VirtuallyDerived (0x0x7fd42c02d2d8) 

     vptridx=8u vbaseoffset=-40 


Vtable for OtherVirtuallyDerived 

OtherVirtuallyDerived::_ZTV21OtherVirtuallyDerived: 8u entries 

0  0u 

8  0u 

16 0u 

24 (int (*)(...))0 

32 (int (*)(...))(& _ZTI21OtherVirtuallyDerived) 

40 (int (*)(...))OtherVirtuallyDerived::~OtherVirtuallyDerived 

48 (int (*)(...))OtherVirtuallyDerived::~OtherVirtuallyDerived 

56 (int (*)(...))OtherVirtuallyDerived::f 


VTT for OtherVirtuallyDerived 

OtherVirtuallyDerived::_ZTT21OtherVirtuallyDerived: 2u entries 

0  ((& OtherVirtuallyDerived::_ZTV21OtherVirtuallyDerived) + 40u) 

8  ((& OtherVirtuallyDerived::_ZTV21OtherVirtuallyDerived) + 40u) 


Class OtherVirtuallyDerived 

    size=8 align=8 

    base size=8 base align=8 

OtherVirtuallyDerived (0x0x7fd42c02d340) 0 nearly-empty 

    vptridx=0u vptr=((& OtherVirtuallyDerived::_ZTV21OtherVirtuallyDerived) + 40u) 

    Base (0x0x7fd42c035900) 0 nearly-empty virtual 

     primary-for OtherVirtuallyDerived (0x0x7fd42c02d340) 

     vptridx=8u vbaseoffset=-40 


Vtable for VirtuallyDiamondDerived 

VirtuallyDiamondDerived::_ZTV23VirtuallyDiamondDerived: 16u entries 

0  0u 

8  0u 

16 0u 

24 (int (*)(...))0 

32 (int (*)(...))(& _ZTI23VirtuallyDiamondDerived) 

40 (int (*)(...))VirtuallyDiamondDerived::~VirtuallyDiamondDerived 

48 (int (*)(...))VirtuallyDiamondDerived::~VirtuallyDiamondDerived 

56 (int (*)(...))VirtuallyDiamondDerived::f 

64 18446744073709551608u 

72 18446744073709551608u 

80 18446744073709551608u 

88 (int (*)(...))-8 

96 (int (*)(...))(& _ZTI23VirtuallyDiamondDerived) 

104 (int (*)(...))VirtuallyDiamondDerived::_ZThn8_N23VirtuallyDiamondDerivedD1Ev 

112 (int (*)(...))VirtuallyDiamondDerived::_ZThn8_N23VirtuallyDiamondDerivedD0Ev 

120 (int (*)(...))VirtuallyDiamondDerived::_ZThn8_N23VirtuallyDiamondDerived1fEv 


Construction vtable for VirtuallyDerived (0x0x7fd42c02d3a8 instance) in VirtuallyDiamondDerived 

VirtuallyDiamondDerived::_ZTC23VirtuallyDiamondDerived0_16VirtuallyDerived: 8u entries 

0  0u 

8  0u 

16 0u 

24 (int (*)(...))0 

32 (int (*)(...))(& _ZTI16VirtuallyDerived) 

40 0u 

48 0u 

56 (int (*)(...))VirtuallyDerived::f 


Construction vtable for OtherVirtuallyDerived (0x0x7fd42c02d410 instance) in VirtuallyDiamondDerived 

VirtuallyDiamondDerived::_ZTC23VirtuallyDiamondDerived8_21OtherVirtuallyDerived: 15u entries 

0  18446744073709551608u 

8  0u 

16 0u 

24 (int (*)(...))0 

32 (int (*)(...))(& _ZTI21OtherVirtuallyDerived) 

40 0u 

48 0u 

56 (int (*)(...))OtherVirtuallyDerived::f 

64 8u 

72 8u 

80 (int (*)(...))8 

88 (int (*)(...))(& _ZTI21OtherVirtuallyDerived) 

96 0u 

104 0u 

112 (int (*)(...))OtherVirtuallyDerived::_ZTv0_n32_N21OtherVirtuallyDerived1fEv 


VTT for VirtuallyDiamondDerived 

VirtuallyDiamondDerived::_ZTT23VirtuallyDiamondDerived: 7u entries 

0  ((& VirtuallyDiamondDerived::_ZTV23VirtuallyDiamondDerived) + 40u) 

8  ((& VirtuallyDiamondDerived::_ZTC23VirtuallyDiamondDerived0_16VirtuallyDerived) + 40u) 

16 ((& VirtuallyDiamondDerived::_ZTC23VirtuallyDiamondDerived0_16VirtuallyDerived) + 40u) 

24 ((& VirtuallyDiamondDerived::_ZTC23VirtuallyDiamondDerived8_21OtherVirtuallyDerived) + 40u) 

32 ((& VirtuallyDiamondDerived::_ZTC23VirtuallyDiamondDerived8_21OtherVirtuallyDerived) + 96u) 

40 ((& VirtuallyDiamondDerived::_ZTV23VirtuallyDiamondDerived) + 40u) 

48 ((& VirtuallyDiamondDerived::_ZTV23VirtuallyDiamondDerived) + 104u) 


Class VirtuallyDiamondDerived 

    size=16 align=8 

    base size=16 base align=8 

VirtuallyDiamondDerived (0x0x7fd42c07e460) 0 

    vptridx=0u vptr=((& VirtuallyDiamondDerived::_ZTV23VirtuallyDiamondDerived) + 40u) 

    VirtuallyDerived (0x0x7fd42c02d3a8) 0 nearly-empty 

     primary-for VirtuallyDiamondDerived (0x0x7fd42c07e460) 

     subvttidx=8u 

    Base (0x0x7fd42c035960) 0 nearly-empty virtual 

     primary-for VirtuallyDerived (0x0x7fd42c02d3a8) 

     vptridx=40u vbaseoffset=-40 

    OtherVirtuallyDerived (0x0x7fd42c02d410) 8 nearly-empty 

     lost-primary 

     subvttidx=24u vptridx=48u vptr=((& VirtuallyDiamondDerived::_ZTV23VirtuallyDiamondDerived) + 104u) 

    Base (0x0x7fd42c035960) alternative-path 


Vtable for DoublyVirtuallyDiamondDerived 

DoublyVirtuallyDiamondDerived::_ZTV29DoublyVirtuallyDiamondDerived: 18u entries 

0  8u 

8  0u 

16 0u 

24 0u 

32 0u 

40 (int (*)(...))0 

48 (int (*)(...))(& _ZTI29DoublyVirtuallyDiamondDerived) 

56 (int (*)(...))DoublyVirtuallyDiamondDerived::~DoublyVirtuallyDiamondDerived 

64 (int (*)(...))DoublyVirtuallyDiamondDerived::~DoublyVirtuallyDiamondDerived 

72 (int (*)(...))DoublyVirtuallyDiamondDerived::f 

80 18446744073709551608u 

88 18446744073709551608u 

96 18446744073709551608u 

104 (int (*)(...))-8 

112 (int (*)(...))(& _ZTI29DoublyVirtuallyDiamondDerived) 

120 (int (*)(...))DoublyVirtuallyDiamondDerived::_ZTv0_n24_N29DoublyVirtuallyDiamondDerivedD1Ev 

128 (int (*)(...))DoublyVirtuallyDiamondDerived::_ZTv0_n24_N29DoublyVirtuallyDiamondDerivedD0Ev 

136 (int (*)(...))DoublyVirtuallyDiamondDerived::_ZTv0_n32_N29DoublyVirtuallyDiamondDerived1fEv 


Construction vtable for VirtuallyDerived in DoublyVirtuallyDiamondDerived 

DoublyVirtuallyDiamondDerived::_ZTC29DoublyVirtuallyDiamondDerived0_16VirtuallyDerived: 8u entries 

0  0u 

8  0u 

16 0u 

24 (int (*)(...))0 

32 (int (*)(...))(& _ZTI16VirtuallyDerived) 

40 0u 

48 0u 

56 (int (*)(...))VirtuallyDerived::f 


Construction vtable for OtherVirtuallyDerived in DoublyVirtuallyDiamondDerived 

DoublyVirtuallyDiamondDerived::_ZTC29DoublyVirtuallyDiamondDerived8_21OtherVirtuallyDerived: 15u entries 

0  18446744073709551608u 

8  0u 

16 0u 

24 (int (*)(...))0 

32 (int (*)(...))(& _ZTI21OtherVirtuallyDerived) 

40 0u 

48 0u 

56 (int (*)(...))OtherVirtuallyDerived::f 

64 8u 

72 8u 

80 (int (*)(...))8 

88 (int (*)(...))(& _ZTI21OtherVirtuallyDerived) 

96 0u 

104 0u 

112 (int (*)(...))OtherVirtuallyDerived::_ZTv0_n32_N21OtherVirtuallyDerived1fEv 


VTT for DoublyVirtuallyDiamondDerived 

DoublyVirtuallyDiamondDerived::_ZTT29DoublyVirtuallyDiamondDerived: 8u entries 

0  ((& DoublyVirtuallyDiamondDerived::_ZTV29DoublyVirtuallyDiamondDerived) + 56u) 

8  ((& DoublyVirtuallyDiamondDerived::_ZTV29DoublyVirtuallyDiamondDerived) + 56u) 

16 ((& DoublyVirtuallyDiamondDerived::_ZTV29DoublyVirtuallyDiamondDerived) + 56u) 

24 ((& DoublyVirtuallyDiamondDerived::_ZTV29DoublyVirtuallyDiamondDerived) + 120u) 

32 ((& DoublyVirtuallyDiamondDerived::_ZTC29DoublyVirtuallyDiamondDerived0_16VirtuallyDerived) + 40u) 

40 ((& DoublyVirtuallyDiamondDerived::_ZTC29DoublyVirtuallyDiamondDerived0_16VirtuallyDerived) + 40u) 

48 ((& DoublyVirtuallyDiamondDerived::_ZTC29DoublyVirtuallyDiamondDerived8_21OtherVirtuallyDerived) + 40u) 

56 ((& DoublyVirtuallyDiamondDerived::_ZTC29DoublyVirtuallyDiamondDerived8_21OtherVirtuallyDerived) + 96u) 


Class DoublyVirtuallyDiamondDerived 

    size=16 align=8 

    base size=8 base align=8 

DoublyVirtuallyDiamondDerived (0x0x7fd42c07ea10) 0 nearly-empty 

    vptridx=0u vptr=((& DoublyVirtuallyDiamondDerived::_ZTV29DoublyVirtuallyDiamondDerived) + 56u) 

    VirtuallyDerived (0x0x7fd42c02d478) 0 nearly-empty virtual 

     primary-for DoublyVirtuallyDiamondDerived (0x0x7fd42c07ea10) 

     subvttidx=32u vptridx=8u vbaseoffset=-48 

    Base (0x0x7fd42c035a80) 0 nearly-empty virtual 

     primary-for VirtuallyDerived (0x0x7fd42c02d478) 

     vptridx=16u vbaseoffset=-40 

    OtherVirtuallyDerived (0x0x7fd42c02d4e0) 8 nearly-empty virtual 

     lost-primary 

     subvttidx=48u vptridx=24u vbaseoffset=-56 vptr=((& DoublyVirtuallyDiamondDerived::_ZTV29DoublyVirtuallyDiamondDerived) + 120u) 

    Base (0x0x7fd42c035a80) alternative-path 


Vtable for MixedVirtuallyDerived 

MixedVirtuallyDerived::_ZTV21MixedVirtuallyDerived: 13u entries 

0  8u 

8  (int (*)(...))0 

16 (int (*)(...))(& _ZTI21MixedVirtuallyDerived) 

24 0u 

32 0u 

40 (int (*)(...))OtherBase::g 

48 0u 

56 18446744073709551608u 

64 (int (*)(...))-8 

72 (int (*)(...))(& _ZTI21MixedVirtuallyDerived) 

80 0u 

88 0u 

96 (int (*)(...))__cxa_pure_virtual 


VTT for MixedVirtuallyDerived 

MixedVirtuallyDerived::_ZTT21MixedVirtuallyDerived: 2u entries 

0  ((& MixedVirtuallyDerived::_ZTV21MixedVirtuallyDerived) + 24u) 

8  ((& MixedVirtuallyDerived::_ZTV21MixedVirtuallyDerived) + 80u) 


Class MixedVirtuallyDerived 

    size=16 align=8 

    base size=8 base align=8 

MixedVirtuallyDerived (0x0x7fd42c07eee0) 0 nearly-empty 

    vptridx=0u vptr=((& MixedVirtuallyDerived::_ZTV21MixedVirtuallyDerived) + 24u) 

    Base (0x0x7fd42c035c60) 8 nearly-empty virtual 

     vptridx=8u vbaseoffset=-24 vptr=((& MixedVirtuallyDerived::_ZTV21MixedVirtuallyDerived) + 80u) 

    OtherBase (0x0x7fd42c035cc0) 0 nearly-empty 

     primary-for MixedVirtuallyDerived (0x0x7fd42c07eee0) 


Vtable for MixedVirtuallyDiamondDerived 

MixedVirtuallyDiamondDerived::_ZTV28MixedVirtuallyDiamondDerived: 15u entries 

0  0u 

8  0u 

16 0u 

24 (int (*)(...))0 

32 (int (*)(...))(& _ZTI28MixedVirtuallyDiamondDerived) 

40 (int (*)(...))MixedVirtuallyDiamondDerived::~MixedVirtuallyDiamondDerived 

48 (int (*)(...))MixedVirtuallyDiamondDerived::~MixedVirtuallyDiamondDerived 

56 (int (*)(...))MixedVirtuallyDiamondDerived::f 

64 (int (*)(...))MixedVirtuallyDiamondDerived::g 

72 18446744073709551608u 

80 (int (*)(...))-8 

88 (int (*)(...))(& _ZTI28MixedVirtuallyDiamondDerived) 

96 (int (*)(...))MixedVirtuallyDiamondDerived::_ZThn8_N28MixedVirtuallyDiamondDerivedD1Ev 

104 (int (*)(...))MixedVirtuallyDiamondDerived::_ZThn8_N28MixedVirtuallyDiamondDerivedD0Ev 

112 (int (*)(...))MixedVirtuallyDiamondDerived::_ZThn8_N28MixedVirtuallyDiamondDerived1gEv 


Construction vtable for VirtuallyDerived (0x0x7fd42c02d750 instance) in MixedVirtuallyDiamondDerived 

MixedVirtuallyDiamondDerived::_ZTC28MixedVirtuallyDiamondDerived0_16VirtuallyDerived: 8u entries 

0  0u 

8  0u 

16 0u 

24 (int (*)(...))0 

32 (int (*)(...))(& _ZTI16VirtuallyDerived) 

40 0u 

48 0u 

56 (int (*)(...))VirtuallyDerived::f 


Construction vtable for MixedVirtuallyDerived (0x0x7fd42c0b5380 instance) in MixedVirtuallyDiamondDerived 

MixedVirtuallyDiamondDerived::_ZTC28MixedVirtuallyDiamondDerived8_21MixedVirtuallyDerived: 13u entries 

0  18446744073709551608u 

8  (int (*)(...))0 

16 (int (*)(...))(& _ZTI21MixedVirtuallyDerived) 

24 0u 

32 0u 

40 (int (*)(...))OtherBase::g 

48 0u 

56 8u 

64 (int (*)(...))8 

72 (int (*)(...))(& _ZTI21MixedVirtuallyDerived) 

80 0u 

88 0u 

96 (int (*)(...))__cxa_pure_virtual 


VTT for MixedVirtuallyDiamondDerived 

MixedVirtuallyDiamondDerived::_ZTT28MixedVirtuallyDiamondDerived: 7u entries 

0  ((& MixedVirtuallyDiamondDerived::_ZTV28MixedVirtuallyDiamondDerived) + 40u) 

8  ((& MixedVirtuallyDiamondDerived::_ZTC28MixedVirtuallyDiamondDerived0_16VirtuallyDerived) + 40u) 

16 ((& MixedVirtuallyDiamondDerived::_ZTC28MixedVirtuallyDiamondDerived0_16VirtuallyDerived) + 40u) 

24 ((& MixedVirtuallyDiamondDerived::_ZTC28MixedVirtuallyDiamondDerived8_21MixedVirtuallyDerived) + 24u) 

32 ((& MixedVirtuallyDiamondDerived::_ZTC28MixedVirtuallyDiamondDerived8_21MixedVirtuallyDerived) + 80u) 

40 ((& MixedVirtuallyDiamondDerived::_ZTV28MixedVirtuallyDiamondDerived) + 40u) 

48 ((& MixedVirtuallyDiamondDerived::_ZTV28MixedVirtuallyDiamondDerived) + 96u) 


Class MixedVirtuallyDiamondDerived 

    size=16 align=8 

    base size=16 base align=8 

MixedVirtuallyDiamondDerived (0x0x7fd42c0b5310) 0 

    vptridx=0u vptr=((& MixedVirtuallyDiamondDerived::_ZTV28MixedVirtuallyDiamondDerived) + 40u) 

    VirtuallyDerived (0x0x7fd42c02d750) 0 nearly-empty 

     primary-for MixedVirtuallyDiamondDerived (0x0x7fd42c0b5310) 

     subvttidx=8u 

    Base (0x0x7fd42c035d20) 0 nearly-empty virtual 

     primary-for VirtuallyDerived (0x0x7fd42c02d750) 

     vptridx=40u vbaseoffset=-40 

    MixedVirtuallyDerived (0x0x7fd42c0b5380) 8 nearly-empty 

     subvttidx=24u vptridx=48u vptr=((& MixedVirtuallyDiamondDerived::_ZTV28MixedVirtuallyDiamondDerived) + 96u) 

    Base (0x0x7fd42c035d20) alternative-path 

    OtherBase (0x0x7fd42c035d80) 8 nearly-empty 

     primary-for MixedVirtuallyDerived (0x0x7fd42c0b5380) 


Vtable for VirtuallyMultiplyDerived 

VirtuallyMultiplyDerived::_ZTV24VirtuallyMultiplyDerived: 16u entries 

0  8u 

8  0u 

16 0u 

24 0u 

32 (int (*)(...))0 

40 (int (*)(...))(& _ZTI24VirtuallyMultiplyDerived) 

48 0u 

56 0u 

64 (int (*)(...))__cxa_pure_virtual 

72 0u 

80 18446744073709551608u 

88 (int (*)(...))-8 

96 (int (*)(...))(& _ZTI24VirtuallyMultiplyDerived) 

104 0u 

112 0u 

120 (int (*)(...))OtherBase::g 


VTT for VirtuallyMultiplyDerived 

VirtuallyMultiplyDerived::_ZTT24VirtuallyMultiplyDerived: 3u entries 

0  ((& VirtuallyMultiplyDerived::_ZTV24VirtuallyMultiplyDerived) + 48u) 

8  ((& VirtuallyMultiplyDerived::_ZTV24VirtuallyMultiplyDerived) + 48u) 

16 ((& VirtuallyMultiplyDerived::_ZTV24VirtuallyMultiplyDerived) + 104u) 


Class VirtuallyMultiplyDerived 

    size=16 align=8 

    base size=8 base align=8 

VirtuallyMultiplyDerived (0x0x7fd42c0b59a0) 0 nearly-empty 

    vptridx=0u vptr=((& VirtuallyMultiplyDerived::_ZTV24VirtuallyMultiplyDerived) + 48u) 

    Base (0x0x7fd42c035e40) 0 nearly-empty virtual 

     primary-for VirtuallyMultiplyDerived (0x0x7fd42c0b59a0) 

     vptridx=8u vbaseoffset=-40 

    OtherBase (0x0x7fd42c035ea0) 8 nearly-empty virtual 

     vptridx=16u vbaseoffset=-48 vptr=((& VirtuallyMultiplyDerived::_ZTV24VirtuallyMultiplyDerived) + 104u) 


Vtable for OtherVirtuallyMultiplyDerived 

OtherVirtuallyMultiplyDerived::_ZTV29OtherVirtuallyMultiplyDerived: 16u entries 

0  8u 

8  0u 

16 0u 

24 0u 

32 (int (*)(...))0 

40 (int (*)(...))(& _ZTI29OtherVirtuallyMultiplyDerived) 

48 0u 

56 0u 

64 (int (*)(...))__cxa_pure_virtual 

72 0u 

80 18446744073709551608u 

88 (int (*)(...))-8 

96 (int (*)(...))(& _ZTI29OtherVirtuallyMultiplyDerived) 

104 0u 

112 0u 

120 (int (*)(...))OtherBase::g 


VTT for OtherVirtuallyMultiplyDerived 

OtherVirtuallyMultiplyDerived::_ZTT29OtherVirtuallyMultiplyDerived: 3u entries 

0  ((& OtherVirtuallyMultiplyDerived::_ZTV29OtherVirtuallyMultiplyDerived) + 48u) 

8  ((& OtherVirtuallyMultiplyDerived::_ZTV29OtherVirtuallyMultiplyDerived) + 48u) 

16 ((& OtherVirtuallyMultiplyDerived::_ZTV29OtherVirtuallyMultiplyDerived) + 104u) 


Class OtherVirtuallyMultiplyDerived 

    size=16 align=8 

    base size=8 base align=8 

OtherVirtuallyMultiplyDerived (0x0x7fd42c0b5d90) 0 nearly-empty 

    vptridx=0u vptr=((& OtherVirtuallyMultiplyDerived::_ZTV29OtherVirtuallyMultiplyDerived) + 48u) 

    Base (0x0x7fd42c035f00) 0 nearly-empty virtual 

     primary-for OtherVirtuallyMultiplyDerived (0x0x7fd42c0b5d90) 

     vptridx=8u vbaseoffset=-40 

    OtherBase (0x0x7fd42c035f60) 8 nearly-empty virtual 

     vptridx=16u vbaseoffset=-48 vptr=((& OtherVirtuallyMultiplyDerived::_ZTV29OtherVirtuallyMultiplyDerived) + 104u) 


Vtable for MultiplyVirtuallyDiamondDerived 

MultiplyVirtuallyDiamondDerived::_ZTV31MultiplyVirtuallyDiamondDerived: 26u entries 

0  16u 

8  0u 

16 0u 

24 0u 

32 (int (*)(...))0 

40 (int (*)(...))(& _ZTI31MultiplyVirtuallyDiamondDerived) 

48 (int (*)(...))MultiplyVirtuallyDiamondDerived::~MultiplyVirtuallyDiamondDerived 

56 (int (*)(...))MultiplyVirtuallyDiamondDerived::~MultiplyVirtuallyDiamondDerived 

64 (int (*)(...))MultiplyVirtuallyDiamondDerived::f 

72 (int (*)(...))MultiplyVirtuallyDiamondDerived::g 

80 8u 

88 18446744073709551608u 

96 18446744073709551608u 

104 18446744073709551608u 

112 (int (*)(...))-8 

120 (int (*)(...))(& _ZTI31MultiplyVirtuallyDiamondDerived) 

128 (int (*)(...))MultiplyVirtuallyDiamondDerived::_ZThn8_N31MultiplyVirtuallyDiamondDerivedD1Ev 

136 (int (*)(...))MultiplyVirtuallyDiamondDerived::_ZThn8_N31MultiplyVirtuallyDiamondDerivedD0Ev 

144 0u 

152 18446744073709551600u 

160 18446744073709551600u 

168 (int (*)(...))-16 

176 (int (*)(...))(& _ZTI31MultiplyVirtuallyDiamondDerived) 

184 (int (*)(...))MultiplyVirtuallyDiamondDerived::_ZTv0_n24_N31MultiplyVirtuallyDiamondDerivedD1Ev 

192 (int (*)(...))MultiplyVirtuallyDiamondDerived::_ZTv0_n24_N31MultiplyVirtuallyDiamondDerivedD0Ev 

200 (int (*)(...))MultiplyVirtuallyDiamondDerived::_ZTv0_n32_N31MultiplyVirtuallyDiamondDerived1gEv 


Construction vtable for VirtuallyMultiplyDerived (0x0x7fd42bcdf230 instance) in MultiplyVirtuallyDiamondDerived 

MultiplyVirtuallyDiamondDerived::_ZTC31MultiplyVirtuallyDiamondDerived0_24VirtuallyMultiplyDerived: 16u entries 

0  16u 

8  0u 

16 0u 

24 0u 

32 (int (*)(...))0 

40 (int (*)(...))(& _ZTI24VirtuallyMultiplyDerived) 

48 0u 

56 0u 

64 (int (*)(...))__cxa_pure_virtual 

72 0u 

80 18446744073709551600u 

88 (int (*)(...))-16 

96 (int (*)(...))(& _ZTI24VirtuallyMultiplyDerived) 

104 0u 

112 0u 

120 (int (*)(...))OtherBase::g 


Construction vtable for OtherVirtuallyMultiplyDerived (0x0x7fd42bcdf2a0 instance) in MultiplyVirtuallyDiamondDerived 

MultiplyVirtuallyDiamondDerived::_ZTC31MultiplyVirtuallyDiamondDerived8_29OtherVirtuallyMultiplyDerived: 23u entries 

0  8u 

8  18446744073709551608u 

16 18446744073709551608u 

24 0u 

32 (int (*)(...))0 

40 (int (*)(...))(& _ZTI29OtherVirtuallyMultiplyDerived) 

48 0u 

56 0u 

64 (int (*)(...))__cxa_pure_virtual 

72 0u 

80 8u 

88 (int (*)(...))8 

96 (int (*)(...))(& _ZTI29OtherVirtuallyMultiplyDerived) 

104 0u 

112 0u 

120 (int (*)(...))__cxa_pure_virtual 

128 0u 

136 18446744073709551608u 

144 (int (*)(...))-8 

152 (int (*)(...))(& _ZTI29OtherVirtuallyMultiplyDerived) 

160 0u 

168 0u 

176 (int (*)(...))OtherBase::g 


VTT for MultiplyVirtuallyDiamondDerived 

MultiplyVirtuallyDiamondDerived::_ZTT31MultiplyVirtuallyDiamondDerived: 10u entries 

0  ((& MultiplyVirtuallyDiamondDerived::_ZTV31MultiplyVirtuallyDiamondDerived) + 48u) 

8  ((& MultiplyVirtuallyDiamondDerived::_ZTC31MultiplyVirtuallyDiamondDerived0_24VirtuallyMultiplyDerived) + 48u) 

16 ((& MultiplyVirtuallyDiamondDerived::_ZTC31MultiplyVirtuallyDiamondDerived0_24VirtuallyMultiplyDerived) + 48u) 

24 ((& MultiplyVirtuallyDiamondDerived::_ZTC31MultiplyVirtuallyDiamondDerived0_24VirtuallyMultiplyDerived) + 104u) 

32 ((& MultiplyVirtuallyDiamondDerived::_ZTC31MultiplyVirtuallyDiamondDerived8_29OtherVirtuallyMultiplyDerived) + 48u) 

40 ((& MultiplyVirtuallyDiamondDerived::_ZTC31MultiplyVirtuallyDiamondDerived8_29OtherVirtuallyMultiplyDerived) + 104u) 

48 ((& MultiplyVirtuallyDiamondDerived::_ZTC31MultiplyVirtuallyDiamondDerived8_29OtherVirtuallyMultiplyDerived) + 160u) 

56 ((& MultiplyVirtuallyDiamondDerived::_ZTV31MultiplyVirtuallyDiamondDerived) + 48u) 

64 ((& MultiplyVirtuallyDiamondDerived::_ZTV31MultiplyVirtuallyDiamondDerived) + 184u) 

72 ((& MultiplyVirtuallyDiamondDerived::_ZTV31MultiplyVirtuallyDiamondDerived) + 128u) 


Class MultiplyVirtuallyDiamondDerived 

    size=24 align=8 

    base size=16 base align=8 

MultiplyVirtuallyDiamondDerived (0x0x7fd42bcdf1c0) 0 

    vptridx=0u vptr=((& MultiplyVirtuallyDiamondDerived::_ZTV31MultiplyVirtuallyDiamondDerived) + 48u) 

    VirtuallyMultiplyDerived (0x0x7fd42bcdf230) 0 nearly-empty 

     primary-for MultiplyVirtuallyDiamondDerived (0x0x7fd42bcdf1c0) 

     subvttidx=8u 

    Base (0x0x7fd42bce2000) 0 nearly-empty virtual 

     primary-for VirtuallyMultiplyDerived (0x0x7fd42bcdf230) 

     vptridx=56u vbaseoffset=-40 

    OtherBase (0x0x7fd42bce2060) 16 nearly-empty virtual 

     vptridx=64u vbaseoffset=-48 vptr=((& MultiplyVirtuallyDiamondDerived::_ZTV31MultiplyVirtuallyDiamondDerived) + 184u) 

    OtherVirtuallyMultiplyDerived (0x0x7fd42bcdf2a0) 8 nearly-empty 

     lost-primary 

     subvttidx=32u vptridx=72u vptr=((& MultiplyVirtuallyDiamondDerived::_ZTV31MultiplyVirtuallyDiamondDerived) + 128u) 

    Base (0x0x7fd42bce2000) alternative-path 

    OtherBase (0x0x7fd42bce2060) alternative-path

Fuente

2015-01-26 17:50:25 LThode

¿Cuál es el diseño de VTable y la ubicación del puntero VTable en objetos C++ en GCC 3.xy 4.x?

Respuesta

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