Durandin Vladimir. Lab 3. Option 2.

[Sturmannn]

Implemented Pass, which

Counts the number of machine instructions executed during the execution of a function (excluding program counter increments).

You suggested

To make it easier to select a register to store the counter in a global variable, you can define and initialize it in a function.

But the simple instruction ic = 0 does not allow access to the register, due to the fact that this instruction does not work with registers, but only with memory.
This can be solved by initializing it with a more complex object, but I decided to create my own virtual register for the counter. This allows you to avoid adding initialization of the is variable inside the function.

Example:

// test.cpp
void empty_func() {}

; test.ll
; Function Attrs: mustprogress noinline nounwind optnone uwtable
define dso_local void @_Z10empty_funcv() #0 {
entry:
  ret void
}

# test_input.mir
  bb.0.entry:
    frame-setup PUSH64r killed $rbp, implicit-def $rsp, implicit $rsp
    frame-setup CFI_INSTRUCTION def_cfa_offset 16
    frame-setup CFI_INSTRUCTION offset $rbp, -16
    $rbp = frame-setup MOV64rr $rsp
    frame-setup CFI_INSTRUCTION def_cfa_register $rbp
    $rbp = frame-destroy POP64r implicit-def $rsp, implicit $rsp
    frame-destroy CFI_INSTRUCTION def_cfa $rsp, 8
    RET64

# test_output.mir
  bb.0.entry:
    MOV64mr %0, &ic
    frame-setup PUSH64r killed $rbp, implicit-def $rsp, implicit $rsp
    frame-setup CFI_INSTRUCTION def_cfa_offset 16
    frame-setup CFI_INSTRUCTION offset $rbp, -16
    $rbp = frame-setup MOV64rr $rsp
    frame-setup CFI_INSTRUCTION def_cfa_register $rbp
    $rbp = frame-destroy POP64r implicit-def $rsp, implicit $rsp
    frame-destroy CFI_INSTRUCTION def_cfa $rsp, 8
    %0:gr64 = ADD64ri8 %0, 8, implicit-def $eflags
    RET64