Win32AttachOperationRequest seems to be using global new?

[Julian Waters]

Bumping, I'm still curious about this issue

best regards,
Julian

On Tue, Nov 12, 2024 at 10:20 PM Julian Waters <tanksherman27 at gmail.com> wrote:
>
> Hi all,
>
> Win32AttachOperationRequest is created via new, but doesn't specify a custom new inside the class definition. The result seems to be that we use global new on Windows:
>
>   for (int i=0; i<max_enqueued_operations; i++) {
>     Win32AttachOperationRequest* op = new Win32AttachOperationRequest();
>       f1: b9 28 0d 00 00       mov    ecx,0xd28
>       f6: e8 00 00 00 00       call   fb <Win32AttachListener::init()+0x7b>
> f7: IMAGE_REL_AMD64_REL32 operator new(unsigned long long)
>
> Stepping away from gcc's objdump and using the Microsoft dumpbin alongside cl.exe instead, the result is this:
>
>   0000000000000264: B9 28 0D 00 00     mov         ecx,0D28h
>   0000000000000269: E8 00 00 00 00     call        ??2 at YAPEAX_K@Z
>   000000000000026E: 48 89 44 24 28     mov         qword ptr [rsp+28h],rax
>   0000000000000273: 48 83 7C 24 28 00  cmp         qword ptr [rsp+28h],0
>   0000000000000279: 74 11              je          000000000000028C
>   000000000000027B: 48 8B 4C 24 28     mov         rcx,qword ptr [rsp+28h]
>   0000000000000280: E8 00 00 00 00     call        ??0Win32AttachOperationRequest@@QEAA at XZ
>
> undname "??2 at YAPEAX_K@Z"
> Microsoft (R) C++ Name Undecorator
> Copyright (C) Microsoft Corporation. All rights reserved.
>
> Undecoration of :- "??2 at YAPEAX_K@Z"
> is :- "void * __ptr64 __cdecl operator new(unsigned __int64)"
>
> undname "??0Win32AttachOperationRequest@@QEAA at XZ"
> Microsoft (R) C++ Name Undecorator
> Copyright (C) Microsoft Corporation. All rights reserved.
>
> Undecoration of :- "??0Win32AttachOperationRequest@@QEAA at XZ"
> is :- "public: __cdecl Win32AttachOperationRequest::Win32AttachOperationRequest(void) __ptr64"
>
> Visual Studio, lacking the nm utility, obviously doesn't catch this. What was more surprising is that the gcc Link Time check also fails to catch it as well. I had to manually check the output of nm after an unrelated failure and happened to stumble across the symbols _Znwy and _ZdlPvy which both correspond to
>
> operator new(unsigned long long)
> operator delete(void*, unsigned long long)
>
> The delete can be ignored, it's the result of a bug on my experimental branch (It was first discovered there, then I tested it on master). I'm more interested about the new, since it seems to be violating a HotSpot rule. Is this an intentional exception to the rule, or an oversight?
>
> best regards,
> Julian