* Add CoreCLR compilation support for Apple Silicon
    * Use CMAKE_OSX_ARCH rework
    * Set clang -arch flag
    * Workaround uname arch reporting emulated arch

* Fix native code compilation issues
* Implement missing osx-arm64 functionality
* Prototype fix for write no execute issues
* Strip libunwind pointer authentication bits

* Review feedback
* Does not fix Arm64 ABI issues
Co-authored-by: NJan Vorlicek <janvorli@microsoft.com>

* upgrade to net6.0

* add comment and update package version

* address feedback and fix failures

* address feedbacl

* address feedback

In #2249, we started doing alignment of methods to 32-byte boundary for Tier1. However, a method having loops bypass tiering and hence this condition was never executed. Fixed it to make sure we do the alignment for optimized methods only and don't do it for prejitted methods.

* Allow enregistering more structs args

Allow HFAs and other structs with matching fields and registers.

Contributes to #37924

Expand usage of w32subset API partitioning making it possible to include/exclude/use/replace different subset of Win32 API's.

Merge UWP source files into regular Windows specific source files keeping one set of Windows implementation files in upstream repro leverage w32subset.h to support CLASSIC or UWP API subsets.

PR also extend capabilities to replace API usage using HAVE_EXTERN_DEFINED_WIN32* making it possible to exclude and replace API usage in downstream repositories.
Co-authored-by: NlateralusX <lateralusX@users.noreply.github.com>

* Console.Unix: reset terminal at exit in less cases to avoid blocking the parent.

When a parent is fetching the Console.Cursor position, it configures the terminal
to not echo, writes an escape sequence to query the position, and then reads the
position from stdin.

Because this doesn't happen atomically a child process can overwrite the terminal
settings to echo before the parent starts reading. This causes the position to
be echoed to the user, and the parent gets stuck waiting for input on stdin.

Currently terminal settings are reset at exit for applications that use the
Console or Process class. This change tracks whether the application has
changes the terminal settings and only then resets the terminal settings.

This doesn't fix the issue, but makes it less likely to occur.

* TermInfo changes are no longer needed

* Only configure terminal for child if we've touched the settings.

* minor change to comment wording

* add System.Net.Quic assembly and use it in HttpClient

* fix build issue

* remove old quic code from shared directory

* fix Common.Tests project

* fix WinHttp tests

* fix typo
Co-authored-by: NGeoffrey Kizer <geoffrek@windows.microsoft.com>

* Start stopwatch immediately before sending http request

* Remove extra line

* Remove trailing white space

* Introduce a concept of minimum array length into range check

* Some cleanup

* fix potential underflow

* bug fix and cleanup

* Revert string changes

* Allow elimination of arr[0] with  len != 0 test

* Revert "Revert string changes"

This reverts commit 6f77bf8c8acce1f5382bb704875384c6f8e2f984.

* Fix up tests

* reverting lower bound merging as it may be unsound

* Fix CI exposed bug and add a couple of test cases

* code review feedback

* comment nit

* feedback

* Add missing break

* Update function pointer syntax usage to official.

* Fix warnings with new Roslyn
Co-authored-by: NJan Kotas <jkotas@microsoft.com>

* Clear the low bit of "Function Start RVA" on Arm Thumb2 machines in ReadyToRunMethod.cs

* Remove restrictions on InputArchitecture in ReadyToRunReader.cs and R2RDump.cs

RMW intrinsic operands doesn't have to be marked as "delay-free" when they can be assigned the same register as op1Reg (i.e. read-modify-write operand) and one of them is the last use.

One of the problems with BGC sweep is it zeros out the gen2 FL at the beginning which means we might need to increase gen2 size before it builds up enough FL to accommodate gen1 survivors. To lift this limitation I'm changing this to a doubly linked list so we can easily take items off and thread new ones back on.

Note that this is the initial checkin for the feature - there needs to be more stress testing and perf testing done on this so I'm checking in with the feature DOUBLY_LINKED_FL undefined. I've done some stress testing but not a whole lot.

This is only used for gen2 FL, not UOH - we already don't allow UOH allocations while we are sweeping UOH (which should be quite quick). In the future we will make it work so UOH allocs are allowed while it's being swept but that's beyond the scope of this feature (it would require work in the synchronization between the allocator and BGC sweep).

2 new bits were introduced -

Previously we didn't need to care about bgc mark bits at all since we can't possibly compact into the part of the heap that hasn't been swept. But now we can. So if we compact into a free item that hasn't been swept, we need to set the mark bits correctly. So we introduce a new bit:

// This bit indicates that we'll need to set the bgc mark bit for this object during an FGC.
// We only do this when we decide to compact.

Also now we don't have the luxury to allocate a min obj in the plan phase if what's allocated in this alloc context is too short. Previously we have this situation:

SB|MT|L|N

and if we plan allocated a min obj in this free item, we can allocate a min free obj right after it because the min free obj will not overwrite anything of that free item:

SB|MT|L|N
min free:
        SB|MT|Payload

since we don't touch SB. But now we have this:

SB|MT|L|N|P

and if we only allocated 3 ptr size into this free item, and if we want to allocate a min free obj, we'd be over writing P (previous pointer of this free item):

SB|MT|L|N |P
        SB|MT|Payload

One note on this is that we check the "allocated size" with (alloc_ptr - start_region), but start_region is updated every time we pad in the same free item. And it's really only necessary for the actual alloc context start (because we just need to preserve that free item's prev). But this is saved by the fact that in gen2 we don't pad. If we do pad in gen2 it would be good to handle this.

This is handled by set_free_obj_in_compact_bit (which sets the new MAKE_FREE_OBJ_IN_COMPACT bit) in adjust_limit where we set the bit and record the size of the "filler object". and we'll actually make the filler obj in gcmemcopy. This means this feature is as of now ONLY FOR 64-bit as the bit we use to do this means we are taking up 3 bits in MT to do our bookkeeping. We could make it work for 32-bit by finding bits in the gap - I haven't done that.

Major areas changed were -
+ allocate_in_older_generation - this also has a complication wrt repair and commit. I introduced the new added list concept so we can repair and commit quickly, with one exception for bucket 0. For b0 since we do discard items, we do need to set prev of discarded items to PREV_EMPTY because we need to indicate that it's not the freelist anymore. However, we can still recover by going through the original head and set the prev of the discarded items one by one which wouldn't be fast so I choose to not do it - the discarded items are generally very small anyway.

+ gcmemcopy - this needs to care about the bits we added.

+ background_sweep - this takes items off of the FL and thread new ones back on. Since this never happens at the same time as the gen1 GCs using these items we don't need synchronization here.

+ allocator class - obviously this needs to care about the prev field now. The principle is we don't touch the prev field in unlink_item (except for the special b0 case) so when we repair we don't need to go repair the prev fields. When we commit, we do need to set the new prev field accordingly (unless for the added list which we would have already set the prev correctly).

---

Fixed some existing bugs -

The refactor change stopped updating next_sweep_obj but it's incorrect because it's used by the verification code in sos so brought that back.

More accounting to count free_list/obj spaces correctly.

---

TODO

Optimizations we can do in background_sweep -

+ Don't need to actually take items off if we are just going to thread back on the same one (and others from my design notes);

+ If there's a big item we may not want to remove, imagine this simplied scenario - we have 1 2-mb free item on the list and we just removed it. Now current_num_objs happens to be big enough so we left an FGC happen and this FGC is gen1 and now it doesn't find any free space and would have to grow gen2.

It's actually beneficial to switch to using the added list even for singly linked list so we could consider enabling it even when the feature is not on.

- Fix last issue causing significant misbehavior in X86 Crossgen2 testing
  - Correctly report struct types in asCorInfoType for normalized structs
  - Previous efforts would not report the struct if it was normalized, where the correct behavior was to normalize, and report the struct if it isn't an enum

Around September 25 several dozens of Crossgen2 tests started
failing with a runtime error around incomplete instantiation of
GetArrayDataReference. I believe that for generic methods we
should skip the METHOD_ENTRY_DEF_TOKEN shortcut, otherwise we
lose the instantiation information and cause the runtime problem.

I originally thought this may be related to JanK's function
pointer changes but I no longer believe it is the case
(my apologies to Jan for the false accusation). I rather think
that some ambient code change caused a subtle difference in IL
encoding of access to the method that started tripping the
"shortcut" code path.

Thanks

Tomas

* Expose BackgroundService.ExecuteTask

Expose the task that executes the background service, so consumers can check if it is running and/or has ran to competition or faulted.

Use the new ExecuteTask to log exceptions when a BackgroundService fails after await, instead of appearing to hang.

Fix #35991
Fix #36017

Per https://github.com/dotnet/runtime/pull/43058#discussion_r499896492

* fix async logic in MultipleConnectAsync to avoid lock reentrancy issues

* Update src/libraries/System.Net.Sockets/src/System/Net/Sockets/MultipleConnectAsync.cs
Co-authored-by: NStephen Toub <stoub@microsoft.com>
Co-authored-by: NGeoffrey Kizer <geoffrek@windows.microsoft.com>
Co-authored-by: NStephen Toub <stoub@microsoft.com>

- Use target_size_t when determining if a value fits in a byte when value is represented in the function as a ssize_t or cnssval_ssize_t. This drops the upper 32bits of a possibly 64bit size_t when performing the comparison on TARGET_X86 platforms. Those bits are uninitialized if the value not a reloc.

Don't try to stash field values because in R2R case Jit does not try to read them. It happens only in CoreRun for static readonly fields.

* enable superpmi collection pipeline

In #42053, I forgot to push a change to enable the superpmi pipeline.
This change will trigger it every Sunday at 9:00 AM PST.

* fix space changes

* Update Helix SDK manually

For follow up / if you see 504s

* Fix SPMI dump.

* add a message when we have collisions.

Follow-up to https://github.com/dotnet/runtime/pull/43037#discussion_r499726268

We're installing openssl@1.1 from Homebrew so we should check that version.
It looks like CI Macs don't set the /usr/local/opt/openssl symlink anymore.

For newer Windows SDKs, the stdalign.h header is present, but the alignas macr is not
defined unless the compiler adds the std:c11 or newer.

Until we can set the std:c11 flag, work around the missing alignas macro using cmake config.

* accross -> across

* additionaly -> additionally

* adddress -> address

* addrees -> address

* addresss -> address

* aligment -> alignment

* Alignement -> Alignment

* alredy -> already

* argment -> argument

* Argumemnts -> Arguments

Co-authored-by: Nvargaz <vargaz@users.noreply.github.com>

* Reenable MUSL ARM tests

The packages for MUSL ARM should now be available, so reenable the
libraries tests in the CI

* Update DotnetHost and DotnetHostPolicy versions

* Add Linux arm musl to libraries queues

* Reenabling the arm32 queue in the coreclr templates queues

* Updated versions by darc tool, reverted libraries/helix-queues-setup.yml

With https://github.com/dotnet/xharness/pull/315 we can now make the test output similar to the regular xunit desktop runner.
It no longer prints the passed tests by default, only failing tests. To get the old behavior, add the `-v` flag back to xharness in tests.mobile.targets or check the new wasm-console.log file in the xharness-output folder.

```
  XHarness command issued: wasm test --app=. --engine=V8 --engine-arg=--stack-trace-limit=1000 --js-file=runtime.js --output-directory=/Users/alexander/dev/runtime/artifacts/bin/System.Runtime.Handles.Tests/net5.0-Release/browser-wasm/AppBundle/xharness-output -- --run WasmTestRunner.dll System.Runtime.Handles.Tests.dll -notrait category=OuterLoop -notrait category=failing
  info: 21:57:45.3244690 v8 --expose_wasm --stack-trace-limit=1000 runtime.js -- --run WasmTestRunner.dll System.Runtime.Handles.Tests.dll -notrait category=OuterLoop -notrait category=failing
  info: Arguments: --run,WasmTestRunner.dll,System.Runtime.Handles.Tests.dll,-notrait,category=OuterLoop,-notrait,category=failing
  info: console.debug: MONO_WASM: Initializing mono runtime
  info: console.debug: MONO_WASM: ICU data archive(s) loaded, disabling invariant mode
  info: console.debug: mono_wasm_runtime_ready fe00e07a-5519-4dfe-b35a-f867dbaf2e28
  info: Initializing.....
  info: Discovering: System.Runtime.Handles.Tests.dll (method display = ClassAndMethod, method display options = None)
  info: Discovered:  System.Runtime.Handles.Tests.dll (found 14 of 15 test cases)
  info: Starting:    System.Runtime.Handles.Tests.dll
  fail: [FAIL] SafeWaitHandleTests.SafeWaitHandle_False
  info: Assert.False() Failure
  info: Expected: False
  info: Actual:   True
  info:    at SafeWaitHandleTests.SafeWaitHandle_False()
  info:    at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
  info: Finished:    System.Runtime.Handles.Tests.dll
  info:
  info: === TEST EXECUTION SUMMARY ===
  info: Total: 14, Errors: 0, Failed: 1, Skipped: 0, Time: 0.097211s
  info:
  info: 21:57:46.3323620 Process exited with 1
```

library that can be shared between Mono as well as CoreCLR runtime.

Port follows same guidelines setup for event pipe port #34600.
Diagnostic server library is currently hosted as part of event pipe
library but hosting its own runtime shim as well as source files
(so could be split into separate library if ever make sense).
Diagnostic Server have dependencies on event pipe library
(and reuse part of event pipe runtime shim from its how shim).

This is the first PR getting the code from diagnostic server codebase
over to C library.