[NativeAOT] Implement thunk page generation and mapping for iOS-like platforms

[filipnavara]

Fixes #82090

Marked as draft for the moment since there are still missing bits in the build and test infrastructure. I manually tested it using the PInvoke NativeAOT test compiled for maccatalyst-arm64 and maccatalyst-x64. The PAL interfaces could likely be cleaned up quite a bit since the implementation has different requirements from the old Windows-only code.

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Issue Details

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Fixes #82090

Marked as draft for the moment since there are still missing bits in the build and test infrastructure. I manually tested it using the PInvoke NativeAOT test compiled for maccatalyst-arm64. The x64 code is completely untested but it compiles.

Author:	filipnavara
Assignees:	-
Labels:	area-NativeAOT-coreclr
Milestone:	-

[jkotas]

I manually tested it using the PInvoke NativeAOT test compiled for maccatalyst-arm64 and maccatalyst-x64.

Does this test create enough delegates to hit the mmap path?

[filipnavara]

I manually tested it using the PInvoke NativeAOT test compiled for maccatalyst-arm64 and maccatalyst-x64.

Does this test create enough delegates to hit the mmap path?

No, but I manually modified the thunk allocation to always take the path and it still succeeded.

[filipnavara]

For reference, here are all the build hacks and steps I did to make the test run.

Start with this branch - https://github.com/filipnavara/runtime/tree/build-hacks. It's PR #82086 and bunch of hacks/fixes stacked on top of it.

Build with the following steps:

./build.sh clr+clr.aot
./build.sh clr.nativeaotruntime+clr.nativeaotlibs+libs -os maccatalyst
./dotnet.sh build src/coreclr/nativeaot/BuildIntegration/BuildIntegration.proj /p:TargetOS=maccatalyst
./src/tests/build.sh --os maccatalyst arm64 skiptestwrappers skipgeneratelayout -dir:nativeaot/SmokeTests/PInvoke -nativeaot /p:LibrariesConfiguration=Debug
./artifacts/tests/coreclr/maccatalyst.arm64.Debug/nativeaot/SmokeTests/PInvoke/PInvoke/native/PInvoke

It should fail with

...
2023-02-18 21:54:28.730 PInvoke[37508:4288446] Testing Delegate
zsh: abort

Then merge this feature branch on top, rebuild the runtime, rebuild the test and rerun it:

git merge thunks-1
./build.sh clr.nativeaotruntime+clr.nativeaotlibs+libs -os maccatalyst
./dotnet.sh build src/coreclr/nativeaot/BuildIntegration/BuildIntegration.proj /p:TargetOS=maccatalyst
./src/tests/build.sh --os maccatalyst arm64 skiptestwrappers skipgeneratelayout -dir:nativeaot/SmokeTests/PInvoke -nativeaot /p:LibrariesConfiguration=Debug
./artifacts/tests/coreclr/maccatalyst.arm64.Debug/nativeaot/SmokeTests/PInvoke/PInvoke/native/PInvoke

The test will succeed.

In order to test the mmap part I commented out this line.

[jkotas]

LGTM. Thank you!