The stack structure of function call

The stack structure of the function call process was previously known until Tuesday, when a colleague from the technical salon made a different point of view and was unable to answer it.

The test code is as follows:

intAddintAintb) {    inti = A +b; returni;}intFuncintAintb) {    returnAdd (3, 5); }intMain () {intA = func (3,5); return 0;}

Linux generates the assembly code as follows:

Add:.LFB0:. Cfi_startproc PUSHL%ebp; save Ebp. Cfi_def_cfa_offset8. Cfi_offset5, -8movl%esp,%EBP; esp points to the bottom of the stack. Cfi_def_cfa_register5Subl $ -,%esp; reserved stack space movl A(%EBP),%eax movl8(%EBP),%edx addl%edx,%eax movl%eax,-4(%EBP) MOVL-4(%EBP),%eaxleave; see Assembly instruction explanation. Cfi_restore5. CFI_DEF_CFA4,4    retSee assembly instruction explanation. Cfi_endproc.LFE0:. SizeAdd, .-Add. globl func. Type func, @functionfunc:.LFB1:. Cfi_startproc PUSHL%ebp; ebp into the stack. Cfi_def_cfa_offset8. Cfi_offset5, -8movl%esp,%EBP; esp points to the bottom of the stack. Cfi_def_cfa_register5Subl $8,%esp MOVL $5,4(%ESP) MOVL $3, (%ESP)Pager    Add, return the address into the stack and jump to add    Leave. Cfi_restore5. CFI_DEF_CFA4,4    ret. Cfi_endproc.LFE1:. Size func,.-func. GLOBL Main. Type Main, @function

A compilation of several instructions explains:

Call

Push EIP

jmp

Leave

MOV ESP,EBP

Pop EBP

Ret:

Pop EIP

Add esp,4

Pop EIP:

mov EIP, [ESP]

Add esp,4

Stack structure diagram:

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Ebp

Local variable

5; Func Stack Frames

3

return address

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EBP; Save the func ebp

Local variable

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The stack structure of function call