JIT ARM64: Funclets with "frame type 5" not handled correctly

[jakobbotsch]

Description

Funclets with large frame sizes in functions using stackalloc use an unusual kind of frame. The JIT does not generate correct prolog code for these funclets.

Reproduction Steps

using System;
using System.Runtime.CompilerServices;

public class Program
{
    public static unsafe void Main()
    {
        int* foo = stackalloc int[30];
        try
        {
            Console.WriteLine("try");
            throw new Exception();
        }
        catch (Exception)
        {
            Console.WriteLine("catch");
            foo[0] = 10;
            ManyArgs(new Guid(foo[0], 0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
        }
        Console.WriteLine("after");
    }

    [MethodImpl(MethodImplOptions.NoInlining)]
    private static void ManyArgs(
        Guid g0 = default,
        Guid g1 = default,
        Guid g2 = default,
        Guid g3 = default,
        Guid g4 = default,
        Guid g5 = default,
        Guid g6 = default,
        Guid g7 = default,
        Guid g8 = default,
        Guid g9 = default,
        Guid g10 = default,
        Guid g11 = default,
        Guid g12 = default,
        Guid g13 = default,
        Guid g14 = default,
        Guid g15 = default,
        Guid g16 = default,
        Guid g17 = default,
        Guid g18 = default,
        Guid g19 = default,
        Guid g20 = default,
        Guid g21 = default,
        Guid g22 = default,
        Guid g23 = default,
        Guid g24 = default,
        Guid g25 = default,
        Guid g26 = default,
        Guid g27 = default,
        Guid g28 = default,
        Guid g29 = default,
        Guid g30 = default,
        Guid g31 = default,
        Guid g32 = default,
        Guid g33 = default,
        Guid g34 = default,
        Guid g35 = default,
        Guid g36 = default,
        Guid g37 = default,
        Guid g38 = default,
        Guid g39 = default,
        Guid g40 = default,
        Guid g41 = default)
    {
    }
}

Expected behavior

Prints "try", "catch" and "after".

Actual behavior

"after" is not printed.

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

The JIT generates the following prolog for the funclet:

G_M27646_IG06:              ;; offset=00C0H
        F90007F3          str     x19, [sp,#8]
        A9017BFD          stp     fp, lr, [sp,#16]
        D10983FF          sub     sp, sp, #608
        910043A3          add     x3, fp, #16
        F90133E3          str     x3, [sp,#608]

This overrides caller stack with callee saves.

cc @dotnet/jit-contrib

[ghost]

Tagging subscribers to this area: @JulieLeeMSFT
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

Funclets with large frame sizes in functions using stackalloc use an unusual kind of frame. The JIT does not generate correct prolog code for these funclets.

Reproduction Steps

using System;
using System.Runtime.CompilerServices;

public class Program
{
    public static unsafe void Main()
    {
        int* foo = stackalloc int[30];
        try
        {
            Console.WriteLine("try");
            throw new Exception();
        }
        catch (Exception)
        {
            Console.WriteLine("catch");
            foo[0] = 10;
            ManyArgs(new Guid(foo[0], 0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
        }
        Console.WriteLine("after");
    }

    [MethodImpl(MethodImplOptions.NoInlining)]
    private static void ManyArgs(
        Guid g0 = default,
        Guid g1 = default,
        Guid g2 = default,
        Guid g3 = default,
        Guid g4 = default,
        Guid g5 = default,
        Guid g6 = default,
        Guid g7 = default,
        Guid g8 = default,
        Guid g9 = default,
        Guid g10 = default,
        Guid g11 = default,
        Guid g12 = default,
        Guid g13 = default,
        Guid g14 = default,
        Guid g15 = default,
        Guid g16 = default,
        Guid g17 = default,
        Guid g18 = default,
        Guid g19 = default,
        Guid g20 = default,
        Guid g21 = default,
        Guid g22 = default,
        Guid g23 = default,
        Guid g24 = default,
        Guid g25 = default,
        Guid g26 = default,
        Guid g27 = default,
        Guid g28 = default,
        Guid g29 = default,
        Guid g30 = default,
        Guid g31 = default,
        Guid g32 = default,
        Guid g33 = default,
        Guid g34 = default,
        Guid g35 = default,
        Guid g36 = default,
        Guid g37 = default,
        Guid g38 = default,
        Guid g39 = default,
        Guid g40 = default,
        Guid g41 = default)
    {
    }
}
` `

### Expected behavior

Prints "try", "catch" and "after".

### Actual behavior

"after" is not printed.

### Regression?

_No response_

### Known Workarounds

_No response_

### Configuration

_No response_

### Other information

The JIT generates the following prolog for the funclet:

```asm
G_M27646_IG06:              ;; offset=00C0H
        F90007F3          str     x19, [sp,#8]
        A9017BFD          stp     fp, lr, [sp,#16]
        D10983FF          sub     sp, sp, #608
        910043A3          add     x3, fp, #16
        F90133E3          str     x3, [sp,#608]

This overrides caller stack with fp/lr.

cc @dotnet/jit-contrib

Author:	jakobbotsch
Assignees:	-
Labels:	area-CodeGen-coreclr
Milestone:	7.0.0

[AndyAyersMS]

Also worth noting that very large funclet frames won't do stack probing. OSR hits this in GitHub_21999 because it has to pad the funclet frame with the Tier0 frame size.

[JulieLeeMSFT]

Assigining Arm64 issues to @kunalspathak. Please redistrubte to members.

[BruceForstall]

@kunalspathak Can I take this?

[kunalspathak]

Sure