Add rusty stack protector

[SparrowLii]

MCP: rust-lang/compiler-team#841

This draft PR is a prototype for Rust's stack protection option.

The following are the initially proposed function check rules for rusty mode that require stack protection in Rust(Reference for clang here):

• calls to stack memory allocation (Although there is no direct function in the Rust standard library that provides this functionality)
• obtaining reference/pointer of local variables
  Arrays and references/pointers in Rust are of different types. If you want to use an array to manipulate stack space to cause a buffer overflow, you must first obtain a reference/pointer to it. Therefore, there is no need to specify stack protection rules for arrays in Rust.

Problems that require further discussion：

• How to identify inline scenarios and make corresponding strategy adjustments
• Figure out how the Rust compiler passes large structures (whether it will be optimized to pass by reference)
• How to identify stack memory allocation functions more effectively

And changes to GlobalContext need to be avoided. I'm trying to think of a more convenient way than adding a new query.

r? @ghost

[Noratrieb]

This is not correct for incremental (it's good enough to collect some data but would have to be fixed before merging). One implementation strategy I would try is to use the same mechanism as the (I forgot how exactly it's called) inferred function attrs thing pcwalton implemented a while ago.

[SparrowLii]

Yea, I think so. I'm trying to think of a more convenient way than adding a new query

[SparrowLii]

Thanks! I will learn the strategy you mentioned.

[rcvalle]

Let's just call it strong instead of rusty to avoid confusion, since it's actually the strong equivalent for Rust, and it won't be recommended for anyone to use Clang/LLVM's strong.