calli target fail to inline

[nxtn]

The callers can be inline after dotnet/coreclr#13756, but the callees can't.

.assembly extern legacy library mscorlib {}

.assembly legacy library calli_inline {}
.class private auto ansi beforefieldinit calli_test
       extends [mscorlib]System.Object
{
  .field private static int32 a
  .method public static int32 f1() aggressiveinlining aggressiveoptimization
  {
    ldsfld int32 calli_test::a
    ret
  }
  .method public static int32 g1() aggressiveinlining aggressiveoptimization
  {
    ldftn int32 calli_test::f1()
    calli int32 ()
    ret
  }
  .method public hidebysig static int32 Main() cil managed aggressiveoptimization
  {
    .entrypoint
    .maxstack  2
    call int32 calli_test::g1()
    call string [mscorlib]System.Console::ReadLine()
    pop
    ret
  }
}

Actual:

push    rsi
sub     rsp,20h

mov     rax,offset calli_test.f1()
call    rax
mov     esi,eax
call    System.Console.ReadLine()
mov     eax,esi

add     rsp,20h
pop     rsi
ret

Expected:

push    rsi
sub     rsp,20h

mov     esi,[]
call    System.Console.ReadLine()
mov     eax,esi

add     rsp,20h
pop     rsi
ret

---

However, when I printed the stack trace from inside the callee, it doesn't show up. Earlier I was using stack trace to determine if a method is inline.

  .method public static int32 f1() aggressiveinlining aggressiveoptimization
  {
    newobj instance void [mscorlib]System.Diagnostics.StackTrace::.ctor()
    callvirt instance string [mscorlib]System.Object::ToString()
    call void [mscorlib]System.Console::WriteLine(string)
    ldsfld int32 calli_test::a
    ret
  }

   at calli_test.Main()

---

(I couldn't figure out how to use jit-dasm in jitutils, it just gave tons of errors!)

category:cq
theme:inlining
skill-level:intermediate
cost:medium

[AaronRobinsonMSFT]

/cc @dotnet/jit-contrib

[hypeartist]

@AndyAyersMS Here is a failing piece of COMPlus_JitDump, can this help?

Invoking compiler for the inlinee method Func`1[Int32][System.Int32]:CallImpl(long,long,long):long :
IL to import:
IL_0000  02                ldarg.0     
IL_0001  03                ldarg.1     
IL_0002  04                ldarg.2     
IL_0003  29 30 00 00 11    calli        0x11000030
IL_0008  2a                ret         

INLINER impTokenLookupContextHandle for Func`1[Int32][System.Int32]:CallImpl(long,long,long):long is 0x00007FF8D7F7D571.
*************** In fgFindBasicBlocks() for Func`1[Int32][System.Int32]:CallImpl(long,long,long):long
Jump targets:
  none
New Basic Block BB08 [0007] created.
BB08 [000..009)
Basic block list for 'Func`1[Int32][System.Int32]:CallImpl(long,long,long):long'

-----------------------------------------------------------------------------------------------------------------------------------------
BBnum BBid ref try hnd                 weight    lp [IL range]     [jump]      [EH region]         [flags]
-----------------------------------------------------------------------------------------------------------------------------------------
BB08 [0007]  1                             1        [000..009)        (return)                     
-----------------------------------------------------------------------------------------------------------------------------------------

*************** Inline @[000035] Starting PHASE Pre-import

*************** Inline @[000035] Finishing PHASE Pre-import

*************** Inline @[000035] Starting PHASE Importation
*************** In impImport() for Func`1[Int32][System.Int32]:CallImpl(long,long,long):long

impImportBlockPending for BB08

Importing BB08 (PC=000) of 'Func`1[Int32][System.Int32]:CallImpl(long,long,long):long'
    [ 0]   0 (0x000) ldarg.0
    [ 1]   1 (0x001) ldarg.1
lvaGrabTemp returning 9 (V09 tmp6) called for Inlining Arg.

    [ 2]   2 (0x002) ldarg.2
    [ 3]   3 (0x003) calli 11000030
In Compiler::impImportCall: opcode is calli, kind=0, callRetType is long, structSize is 0
INLINER: during 'impMarkInlineCandidate' result 'failed this call site' reason 'target not direct managed' for 'Func`1[Int32][System.Int32]:CallImpl(long,long,long):long' calling 'n/a'
INLINER: during 'impMarkInlineCandidate' result 'failed this call site' reason 'target not direct managed'

    [ 1]   8 (0x008) ret

    Inlinee Return expression (before normalization)  =>
               [000065] --CXG-------              *  CALL ind  long  
               [000033] ------------ arg0         +--*  LCL_VAR   long   V06 tmp3         
               [000064] ------------ arg1         +--*  LCL_VAR   long   V09 tmp6         
               [000008] ------------ calli tgt    \--*  LCL_VAR   long   V01 arg1         


    Inlinee Return expression (after normalization) =>
               [000065] --CXG-------              *  CALL ind  long  
               [000033] ------------ arg0         +--*  LCL_VAR   long   V06 tmp3         
               [000064] ------------ arg1         +--*  LCL_VAR   long   V09 tmp6         
               [000008] ------------ calli tgt    \--*  LCL_VAR   long   V01 arg1   

calli target is a pointer to this struct's InstanceMethod (typeof(StructA).GetMethod(nameof(StructA.InstanceMethod)).MethodHandle.GetFunctionPointer()):

	public readonly struct StructA
	{
		private readonly int _v;

		public StructA(int v) => _v = v;

		[MethodImpl(MethodImplOptions.AggressiveInlining)]
		public int InstanceMethod(int a) => a * _v;
	}

[hypeartist]

Seems like this is it (https://github.com/dotnet/runtime/blob/master/src/coreclr/src/jit/importer.cpp#L19673)?

    /* Ignore indirect calls */
    if (call->gtCallType == CT_INDIRECT)
    {
        inlineResult.NoteFatal(InlineObservation::CALLSITE_IS_NOT_DIRECT_MANAGED);
        return;
    }