VC和GCC成员函数指针实现的研究(三)
虚继承
终于到最后的虚继承了。
测试代码如下:
#include <ctime>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <stdint.h>
#include <cstddef>
#include <string>
class foo_a
{
public:
virtual ~foo_a(){}
virtual void info() {
printf("%s:%d\n", __FUNCTION__, __LINE__);
}
void print(){
printf("%s:%d\n", __FUNCTION__, __LINE__);
}
};
class foo_l
{
public:
int l;
foo_l(): l(1){}
virtual void info() {
printf("%s:%d\n", __FUNCTION__, __LINE__);
}
};
class foo_r: virtual public foo_a
{
public:
int r;
foo_r(): r(2){}
};
class foo_c: virtual public foo_l, public foo_r
{
public:
virtual void info() {
printf("%d,%d. %s:%d\n", l, r, __FUNCTION__, __LINE__);
}
};
int main(int argc, char* argv[]) {
void (foo_a::*vptr1)() = &foo_a::info;
void (foo_l::*vptr2)() = &foo_l::info;
void (foo_a::*ptr)() = &foo_a::print;
foo_c c;
foo_r r;
foo_a a;
printf("pword size = %d\n", (int)(sizeof(size_t)));
printf("address of &foo_a::info = 0x%llxH\n", &foo_a::info);
printf("pointer to &foo_a::info = 0x%llxH\n", vptr1);
printf("sizeof vptr = %d\n", (int)(sizeof(vptr1)));
(a.*vptr1)();
(r.*vptr1)();
(c.*vptr1)();
(c.*vptr2)();
c.info();
(c.*ptr)();
return 0;
}
VC虚继承成员函数指针实现
因为是兼容虚继承和非虚继承的，所以赋值的部分的汇编是一样的。这里就不贴了。关键在于执行期它是怎么找到虚基类的。请往下看：
