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comparison doc/disas_examples/x64.win.disas @ 493:75cb8f79d725
- doc and disas examples update about C++ non-trivial aggregates
| author | Tassilo Philipp |
|---|---|
| date | Mon, 21 Mar 2022 14:46:38 +0100 |
| parents | 79b95db3d68f |
| children | fc614cb865c6 |
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| 492:29d09d10ecd9 | 493:75cb8f79d725 |
|---|---|
| 421 add rsp, 56 ; | | 421 add rsp, 56 ; | |
| 422 ret 0 ; | epilog | 422 ret 0 ; | epilog |
| 423 main ENDP | 423 main ENDP |
| 424 | 424 |
| 425 | 425 |
| 426 | |
| 427 ; ---------- C++ trivial and non-trivial aggrs passed to C funcs ----------> | |
| 428 ; | |
| 429 ; struct Trivial { int a; }; | |
| 430 ; struct NonTrivial { int a; NonTrivial() : a(0) {} NonTrivial(const NonTrivial& rhs) : a(rhs.a) { } }; | |
| 431 ; | |
| 432 ; extern "C" { | |
| 433 ; | |
| 434 ; void f1(struct Trivial s) { } | |
| 435 ; void f2(struct NonTrivial s) { } | |
| 436 ; | |
| 437 ; void f() | |
| 438 ; { | |
| 439 ; struct Trivial t; | |
| 440 ; struct NonTrivial n; | |
| 441 ; int a=1; | |
| 442 ; a += 123; | |
| 443 ; f1(t); | |
| 444 ; a -= 123; | |
| 445 ; f2(n); | |
| 446 ; a -= 12; | |
| 447 ; } | |
| 448 ; } | |
| 449 | |
| 450 | |
| 451 | |
| 452 ; output from godbolt compiler explorer w/ msvc 19.0 | |
| 453 | |
| 454 ; ... snip, removed code of ctor and copy ctor ... | |
| 455 | |
| 456 f1 PROC | |
| 457 mov DWORD PTR [rsp+8], ecx | |
| 458 ret 0 | |
| 459 f1 ENDP | |
| 460 | |
| 461 f2 PROC | |
| 462 mov QWORD PTR [rsp+8], rcx | |
| 463 ret 0 | |
| 464 f2 ENDP | |
| 465 | |
| 466 a$ = 32 | |
| 467 n$ = 36 | |
| 468 t$ = 40 | |
| 469 $T1 = 44 | |
| 470 $T2 = 48 | |
| 471 f PROC | |
| 472 $LN3: | |
| 473 sub rsp, 72 ; prolog | |
| 474 lea rcx, QWORD PTR n$[rsp] ; \ this ptr (NULL) | |
| 475 call NonTrivial::NonTrivial(void) ; | NonTrivial::NonTrivial() / ctor | |
| 476 mov DWORD PTR a$[rsp], 1 ; a = 1 | |
| 477 mov eax, DWORD PTR a$[rsp] ; | | |
| 478 add eax, 123 ; | a += 123 | |
| 479 mov DWORD PTR a$[rsp], eax ; / | |
| 480 mov ecx, DWORD PTR t$[rsp] ; f1 arg 0 (struct Trivial), via reg as small struct | |
| 481 call f1 ; call f1(struct Trivial) | |
| 482 mov eax, DWORD PTR a$[rsp] ; | | |
| 483 sub eax, 123 ; | a -= 123 | |
| 484 mov DWORD PTR a$[rsp], eax ; / | |
| 485 lea rax, QWORD PTR $T1[rsp] ; @@@ unsure | |
| 486 mov QWORD PTR $T2[rsp], rax ; ... @@@ | |
| 487 lea rdx, QWORD PTR n$[rsp] ; \ ptr to dest of copy of n | |
| 488 mov rcx, QWORD PTR $T2[rsp] ; | copy n ptr to n | |
| 489 call NonTrivial::NonTrivial(NonTrivial const &) ; / NonTrivial::NonTrivial(const NonTrivial&) / copy ctor | |
| 490 mov rcx, rax ; f2 arg 0 (ptr to copy of struct NonTrivial), via ptr as non-trivial | |
| 491 call f2 ; call f2(struct NonTrivial) | |
| 492 mov eax, DWORD PTR a$[rsp] ; | | |
| 493 sub eax, 12 ; | a -= 12 | |
| 494 mov DWORD PTR a$[rsp], eax ; / | |
| 495 add rsp, 72 ; \ | |
| 496 ret 0 ; | epilog | |
| 497 f ENDP | |
| 498 | |
| 499 | |
| 500 | |
| 426 ; vim: ft=asm | 501 ; vim: ft=asm |
| 427 | 502 |