Ship runtime using DllImportGenerator

[elinor-fung]

Issues to address after the initial merge (#59579):

• [DllImportGenerator] Fix inconsistencies in signature of updated p/invokes #61062
  • Some arguments converted to pointers for fully blittable signatures, but some left as out/ref and relying on source generation - make sure related functions have consistent arguments
• [DllImportGenerator] Improve handling of blittable signatures in source generator #60596
  • Detect blittable signatures and generate partial extern p/invokes
• Use GeneratedDllImport for p/invokes in runtime with blittable signatures
  • Update analyzer to also flag blittable signatures as candidates for conversion to GeneratedDllImport
  • Remove the mix of DllImport and GeneratedDllImport and the need to think about which to use based on blittability
    • Use GeneratedDllImport for blittable p/invokes in System.Diagnostics.Process, System.Diagnostics.Process, System.Diagnostics.FileVersionInfo, System.Runtime.InteropServices.RuntimeInformation #61532
    • Use GeneratedDllImport for blittable p/invokes in System.IO.Compression, System.IO.Compression.Brotli, System.Net.Http, System.Net.NameResolution #61638
    • Use GeneratedDllImport for blittable p/invokes in System.Console, System.IO.FileSystem.Watcher, System.IO.Pipes #61996
• [DllImportGenerator] Support down-level targets #60662
  • Allow each marshaller to specify its support
  • Fall back to generating partial extern p/invoke if target version is less than required
• Enable DllImportGenerator by default for all source projects instead of just NETCoreApp (closer to an in-box generator experience) and convert to GeneratedDllImport
  • [DllImportGenerator] Enable on projects without System.Memory and System.Runtime.CompilerServices.Unsafe #61704
  • Convert to OleDb assembly and last Cryptography DllImport to GeneratedDllImport #61184
  • Use DllImportGenerator in System.Diagnostics.PerformanceCounter #61389
  • Remove all DLLIMPORTGENERATOR_ENABLED usage. #61476
  • Use GeneratedDllImport in Microsoft.Win32.SystemEvents #61609
  • Update SPCL to use GeneratedDllImport where possible. #61640
  • Use GeneratedDllImport in System.Data.Odbc, System.IO.Ports, System.ServiceProcess.ServiceController #61741
  • Convert Crypto P/Invokes to GeneratedDllImport. #61742
  • Make System.DirectoryServices.AccountManagement use GeneratedDllImport #61805
  • Use GeneratedDllImport in Microsoft.Extensions.Hosting.WindowsServices, System.Drawing.Primitives, System.Management, System.Security.Cryptography.ProtectedData, System.Speech, System.Windows.Extensions #61949
  • Use GeneratedDllImport in System.DirectoryServices #61975
  • Use GeneratedDllImport in System.Diagnostics.EventLog #61990
• Switch usage of CallingConvention field on GeneratedDllImport to UnmanagedCallConv attribute #61134
• [DllImportGenerator] Remove unnecessary initialization of return values in generated code #60698
• Make QCalls respect EntryPoint #59823
• Update struct marshalling logic based on updated design – Add design details regarding dynamic buffers in struct marshalling #60374
  • [DllImportGenerator] Update buffer size field for custom marshalling #63316
• Update interop guidelines doc in repo to describe source generator usage
  • System.Memory and System.Runtime.CompilerServices.Unsafe for array marshalling
  • Add comment about using source-generated p/invokes to interop guidelines #63350
• Enable using live ref pack in source generator unit tests #60605
  • Add infrastructure to zip live ref assemblies, send to Helix, unzip, and resolve against in source generator unit tests

Runtime issues discovered by DllImportGenerator

• Mono leaks native errno value during UnmanagedCallersOnly prolog/epilog #60271
• JIT assert on arm64 when running DllImportGenerator tests: op2->TypeIs(TYP_LONG) #60624
• Windows x86 CoreCLR assert failure: ExecutionManager::IsManagedCode(GetControlPC(pCF->GetRegisterSet())) #60648
• Mono ARM64 JIT inconsistent with sign-extension #60649
• Mono ignores non-public custom attributes in dynamic assemblies #60650
• JIT assert on arm32 when running DllImportGenerator unit tests: remainingSize == 4 #60705
• Test failure Color.RedirectedOutputDoesNotUseAnsiSequences #60819

cc @AaronRobinsonMSFT @jkoritzinsky

[jkotas]

Allow each marshaller to specify its support

Can this be done by checking availability of the APIs required by the given marshaller?

[jkoritzinsky]

Yes, I believe we can design this such that each marshaller can validate that the APIs it uses are available.

[elinor-fung]

Remaining work for DllImportGenerator - including DisableRuntimeMarshalling for blittable/unmanaged reconciliation - is being tracked in #60595.

This is the drop in generated IL stubs on launch of some template applications after the use of DllImportGenerator in runtime libraries (most remaining stubs in the frameworks):

Template	6.0	7.0
console	2	0
webapp	55	18
winforms	65	55
wpf	129	123