wil VS riscv-j-extension

Even then, MFC and C++/CX were the only productive ways to use it from Microsoft SDKs.

.NET isn't as convenient as VB 6 was, fully embracing COM as the VBX replacement model, technically introduced in VB5, but still some stuff was lacking.

Then there is Delphi and C++ Builder.

It beat me that having doubled down on COM since how Longhorn went down, and Windows team getting their way doing avoiding .NET to take over, they hardly managed to create nice tooling as the competition.

Editing IDL files with a Notepad like experience, manually merging generated code, and a couple of frameworks that barely go beyond yet another way to do AddRef/Release/QueryInterface and aggregation.

Meanwhile D-BUS, XPC and AIDL, provide much better dev experience.

Pity that Borland products are kind of tainted due to mismanagement decisions, otherwise maybe fixing COM dev experience would already been seriously taken by VS team.

Ah, nowadays WIL is probably the best approach when having only to consume COM.

https://github.com/microsoft/wil

Have a look at WIL for a C++ library used by Microsoft themselves, including kernel development.

I'm digging for more information and it looks like Microsoft's created a way to handle the problems I'm trying to address with this: https://github.com/Microsoft/wil/wiki/RAII-resource-wrappers

Since we are on this subject, those that need a nice C++ library to deal with COM in VC++, are better served with WIL.

Not since Vista.

https://docs.microsoft.com/en-us/cpp/build/reference/kernel-...

> Creates a binary that can be executed in the Windows kernel. The code in the current project gets compiled and linked by using a simplified set of C++ language features that are specific to code that runs in kernel mode.

And then there is WIL, https://github.com/microsoft/wil

https://community.osr.com/discussion/291326/the-new-wil-libr...

> First off, let me point out that this library is used to implement large parts of the OS. There are hundreds of developers here who use it. So unlike, uh, some other things that get tossed onto github, this project is not likely to wither and die tomorrow.

> There are, however, only a handful of kernel developers working on the library, so the kernel support has been coming along much slower. I'd like to expand the existing kernel features in depth ....

> Plus C++ standard library can't be used anyway and auto pointers aren't really that much of a concern at the kernel level

https://github.com/microsoft/wil

"Ah, but that isn't used on the Windows kernel" would be the expected reply, well

https://community.osr.com/discussion/291326/the-new-wil-libr...

"Microsoft's toolchain does not ship a copy of the STL that works in kernel mode. Partly this is because the kernel's CRT doesn't support C++ exceptions. (And partly this is because I/O is wildly different in kernel, so you'd have to rewrite the implementation of all the I/O libraries.)

But for kernel developers, wil ships a subset of an STL implementation. To avoid conflicting with the real STL, it's available under the wistd namespace. The rule of thumb is that wistd::foo is a drop-in replacement for std::foo."

Windows is a mix of legacy C code, which started to be migrated into C++ around the Vista time (hence /kernel in VC++) and .NET/COM (WinRT is basically COM with some extras).

Modern kernel code makes use of WIL.

https://github.com/microsoft/wil

The gains seem to not have been high enough to sustain that project. Nowadays CPUs plan, fuse and reorder so much of micro-code that lower-level languages can sort of be considered virtual as well.

But Java and similar languages extract more freedom-of-operation from the programmer to the runtime: no memory address shenanigans, richer types, and to some extent immutability and sealed chunks of code. All these could be picked up and turned into more performance by the hardware; with some help from the compiler. Sort of like SQL being a 4th-gen language, letting the runtime collect statistics and chose the best course of execution (if you squint at it in the dark with colored glasses)

More recent work about this is to be found on the RISC-V J extension [1], still to be formalized and picked up by the industry. Three features could help dynamic languages:

* Pointer masking: you can fit a lot in the unused higher bits of an address. Some GCs use them to annotate memory (refered-to/visited/unvisited/etc.), but you have to mask them. A hardware assisted mask could help a lot.

* Memory tagging: Helps with security, helps with bounds-checking

* More control over instruction caches

It is sort of stale at the moment, and if you track down the people working on it they've been reassigned to the AI-accelerator craze. But it's going to come back, as Moore's law continues to end and Java's TCO will again be at the top of the bean-counter's stack.

[1] https://github.com/riscv/riscv-j-extension

RISC-V J extension – Instructions for JITs\ (40 comments)

There's a document in there about pointer masking: https://github.com/riscv/riscv-j-extension/blob/master/point...

It seems like the objective of this is to implement different access privileges... but why do you need specialized instructions for this? This is typically done by the OS and memory protection. The pointer masking extension would be to have multiple levels of privilege within a single process? I'm assuming that this is to protect the JIT from a JITted program? Except it's not completely safe, because there might still be bugs in the JIT that could allow messing with the pointer tags. Struggling to think of a real use case.