`Undefined reference` errors when calling a C++ classes' static method from assembly

Here is my code:

1. interruptstubs.s:

.set IRQ_BASE, 0x20

.section .text

.extern _ZN16InterruptManager15handleInterruptEhj

.global _ZN16InterruptManager22IgnoreInterruptRequestEv

.macro HandleException num
.global _ZN16InterruptManager16HandleInterruptException\num\()Ev
_ZN16InterruptManager16HandleInterruptException\num\()Ev:
    movb $\num, (interruptnumber)
    jmp int_bottom
.endm

.macro HandleInterruptRequest num
.global _ZN16InterruptManager26HandleInterruptRequest\num\()Ev
_ZN16InterruptManager26HandleInterruptRequest\num\()Ev:
    movb $\num+IRQ_BASE, (interruptnumber)
    jmp int_bottom
.endm

HandleInterruptRequest 0x00
HandleInterruptRequest 0x01

int_bottom:
    pusha
    pushl %ds
    pushl %es
    pushl %fs
    pushl %gs


    pushl %esp
    push (interruptnumber)
    call _ZN16InterruptManager15handleInterruptEhj
    movl %eax, %esp

    popl %gs
    popl %fs
    popl %es
    popl %ds
    popa

_ZN16InterruptManager22IgnoreInterruptRequestEv:
    iret


.data
    interruptnumber: .byte 0

2. interrupts.h:

class InterruptManager
{
public:
    static uint32_t handleInterrupt(uint8_t interruptNumber, uint32_t esp);
};

3. interrupts.cpp:

#include "interrupts.h"

uint32_t InterruptManager::handleInterrupt(uint8_t interruptNumber, uint32_t esp)
{
    printf((char *)" INTERRUPT");
    return esp;
}

I compile/assemble/link with these commands:

as --32 -o loader.o loader.s
g++ -m32 -Iinclude -fno-use-cxa-atexit -fleading-underscore -fno-exceptions -fno-builtin -nostdlib -fno-rtti -fno-pie -o gdt.o -c gdt.cpp
g++ -m32 -Iinclude -fno-use-cxa-atexit -fleading-underscore -fno-exceptions -fno-builtin -nostdlib -fno-rtti -fno-pie -o port.o -c port.cpp
g++ -m32 -Iinclude -fno-use-cxa-atexit -fleading-underscore -fno-exceptions -fno-builtin -nostdlib -fno-rtti -fno-pie -o interrupts.o -c interrupts.cpp
as --32 -o interruptstubs.o interruptstubs.s
g++ -m32 -Iinclude -fno-use-cxa-atexit -fleading-underscore -fno-exceptions -fno-builtin -nostdlib -fno-rtti -fno-pie -o kernel.o -c kernel.cpp
ld -melf_i386 -no-pie -T linker.ld -o mykernel.bin loader.o gdt.o port.o interrupts.o interruptstubs.o kernel.o

the whole code structure is like this above. uint32_t is defined before and here I didn't show it because I don't think it caused problem.

Now when calling the method 'handleInterrupt()' from the .cpp file in my asm code, it has compile error:

ld: interruptstubs.o: in function `int_bottom':
(.text+0xf): undefined reference to `InterruptManager::handleInterrupt(unsigned char, unsigned int)'

I wonder why it didn't work when linking because I have declared .extern _ZN16InterruptManager15handleInterruptEhj in front of the file.

I have searched almost everything on the Internet and didn't get the answer.