[SUA][IRGen] Change IRGen to emit calls to swift_coroFrameAlloc

[t-rasmud]

When TMO is enabled, change IRGen to pass the newly introduced runtime function swift_coroFrameAlloc (and pass an additional argument — the hash value) instead of malloc when it inserts calls to coro_id_retcon_once. The hashValue is computed based on the current function name (computed in getDiscriminatorForString)

rdar://141235957

[aschwaighofer]

You need to cherry-pick swiftlang/llvm-project#10015 to the llvm-project branch that main builds with (stable/20240723) before merging this PR.
You can then test this PR with the llvm PR using cross repo testing: https://github.com/swiftlang/swift/blob/main/docs/ContinuousIntegration.md#cross-repository-testing

For example, something like the following should work:

Please test with following pull request:
https://github.com/swiftlang//llvm-project/pull/22222

@swift-ci test

Please put this behind an IRGen flag -enable/disable-use-type-malloc-for-coro-frame and have it default to not use this feature yet. You can use this commit b49e30c as a model.

For staging/back-deployment purposes, we will need to call through a stub that checks for the presence of swift_coroFrameAlloc in the runtime library (use a weak symbol ref that it checks for null).

The stub functionality can be added in a later commit.

[t-rasmud]

Please test with following pull request:
swiftlang/llvm-project#10041

@swift-ci test

[t-rasmud]

Please test with following pull request:
swiftlang/llvm-project#10041

@swift-ci test

[t-rasmud]

Please test with following pull request:
swiftlang/llvm-project#10041

@swift-ci test

[aschwaighofer]

This looks good to me.

Things to fix in followups:

1.) For staging/back-deployment purposes, we will need to call through a stub that checks for the presence of swift_coroFrameAlloc in the runtime library (use a weak symbol ref that it checks for null).
2.) Compute a 32bit hash (the function used computes a 16bit truncated value, we should add a new one for this purpose)
3.) Pass a properly constructed malloc_type_id value to the runtime function

[t-rasmud]

Please test with following pull request:
swiftlang/llvm-project#10041

@swift-ci test

[t-rasmud]

Please test with following pull request:
swiftlang/llvm-project#10041

@swift-ci test