Improve updating classes for generics by MichalPetryka · Pull Request #88277 · dotnet/runtime

MichalPetryka · 2023-06-30T22:42:53Z

Informs the JIT that object or IEnumerable (and other non generic types) aren't better than List<_Canon>.

Split off from #88163.

ghost · 2023-06-30T22:43:07Z

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

Issue Details

Informs the jit that object and IEnumerable aren't better than List<_Canon>.

Author:	MichalPetryka
Assignees:	-
Labels:	`area-CodeGen-coreclr`
Milestone:	-

MichalPetryka · 2023-06-30T22:43:38Z

@MihuBot

EgorBo · 2023-07-01T12:57:41Z

No diffs so apparently it's not needed?

MichalPetryka · 2023-07-01T16:05:56Z

No diffs so apparently it's not needed?

If you check the diffs instead of the summary, you can see that there are a bunch more variables marked ax exact type. Could the lack of assembly diffs be explained with the fact that inlining of shared generics is currently limited?
Additionally, the previous logic was pretty much flawed, blocking things like updating exactness with same type, blocking updating shared generic with exact, non-shared type and saying that non-shared base types were better than the shared generic.

EgorBo · 2023-07-01T16:17:01Z

No diffs so apparently it's not needed?
If you check the diffs instead of the summary, you can see that there are a bunch more variables marked ax exact type. Could the lack of assembly diffs be explained with the fact that inlining of shared generics is currently limited? Additionally, the previous logic was pretty much flawed, blocking things like updating exactness with same type, blocking updating shared generic with exact, non-shared type and saying that non-shared base types were better than the shared generic.

Could the lack of assembly diffs be explained with the fact that inlining of shared generics is currently limited?

I assume it's possible, but then we'd better experiment when we have that sort of inlining because as of now it's not clear what this change brings. Although, we do support inlining of shared generics in some cases (when they don't need a runtime lookup in fact or when generic methods are in the same Class<T>)

MichalPetryka · 2023-07-05T00:42:08Z

@MihuBot

MichalPetryka · 2023-07-05T02:51:07Z

@EgorBo After the fixes to the jit-diff bot, the PR now has some nice diffs (they mostly aren't reflected in size though since most of them seem to be replacing interface calls with direct ones).

EgorBo · 2023-07-05T12:28:16Z

@EgorBo After the fixes to the jit-diff bot, the PR now has some nice diffs (they mostly aren't reflected in size though since most of them seem to be replacing interface calls with direct ones).

can you show some examples? it is hard to believe an interface call has the same codegen size as a direct one

MichalPetryka · 2023-07-05T12:46:30Z

can you show some examples? it is hard to believe an interface call has the same codegen size as a direct one

@@ -224662,9 +224662,9 @@ G_M64338_IG04:
;; size=9 bbWeight=0.50 PerfScore 1.75
G_M64338_IG05:
mov rdi, r14
- mov rdx, r15
mov rsi, r13
- mov r11, 0xD1FFAB1E ; code for System.Collections.IStructuralEquatable:Equals(System.Object,System.Collections.IEqualityComparer):bool:this+ mov rdx, r15+ mov rax, 0xD1FFAB1E ; code for System.Array:System.Collections.IStructuralEquatable.Equals(System.Object,System.Collections.IEqualityComparer):bool:this
cmp dword ptr [rdi], edi
;; size=21 bbWeight=0.50 PerfScore 2.00
G_M64338_IG06:
@@ -224673,7 +224673,7 @@ G_M64338_IG06:
pop r14
pop r15
pop rbp
- tail.jmp [r11]System.Collections.IStructuralEquatable:Equals(System.Object,System.Collections.IEqualityComparer):bool:this+ tail.jmp [rax]System.Array:System.Collections.IStructuralEquatable.Equals(System.Object,System.Collections.IEqualityComparer):bool:this
;; size=11 bbWeight=0.50 PerfScore 2.25
; Total bytes of code 158, prolog size 19, PerfScore 40.80, instruction count 48, allocated bytes for code 158 (MethodHash=5d2c04ad) for method System.Collections.Immutable.ImmutableArray`1[System.__Canon]:System.Collections.IStructuralEquatable.Equals(System.Object,System.Collections.IEqualityComparer):bool:this (FullOpts)
@@ -224759,17 +224759,17 @@ G_M35883_IG07:
;; size=6 bbWeight=0.50 PerfScore 0.88
G_M35883_IG08:
mov rsi, rax
- mov r11, 0xD1FFAB1E ; code for System.Collections.IStructuralEquatable:GetHashCode(System.Collections.IEqualityComparer):int:this- call [r11]System.Collections.IStructuralEquatable:GetHashCode(System.Collections.IEqualityComparer):int:this+ mov rax, 0xD1FFAB1E ; code for System.Array:System.Collections.IStructuralEquatable.GetHashCode(System.Collections.IEqualityComparer):int:this+ call [rax]System.Array:System.Collections.IStructuralEquatable.GetHashCode(System.Collections.IEqualityComparer):int:this
nop - ;; size=17 bbWeight=0.50 PerfScore 1.88+ ;; size=16 bbWeight=0.50 PerfScore 1.88
G_M35883_IG09:
add rsp, 16
pop rbp
ret ;; size=6 bbWeight=0.50 PerfScore 0.88
-; Total bytes of code 114, prolog size 20, PerfScore 30.98, instruction count 34, allocated bytes for code 114 (MethodHash=2def73d4) for method System.Collections.Immutable.ImmutableArray`1[System.__Canon]:System.Collections.IStructuralEquatable.GetHashCode(System.Collections.IEqualityComparer):int:this (FullOpts)+; Total bytes of code 113, prolog size 20, PerfScore 30.88, instruction count 34, allocated bytes for code 113 (MethodHash=2def73d4) for method System.Collections.Immutable.ImmutableArray`1[System.__Canon]:System.Collections.IStructuralEquatable.GetHashCode(System.Collections.IEqualityComparer):int:this (FullOpts)
; ============================================================

@@ -224863,21 +224863,21 @@ G_M31026_IG05:
xor edi, edi
test r14, r14
sete dil
- xor edx, edx+ xor esi, esi
test r13, r13
- sete dl- xor edi, edx+ sete sil+ xor edi, esi
jne G_M31026_IG09
- ;; size=25 bbWeight=0.50 PerfScore 2.12+ ;; size=26 bbWeight=0.50 PerfScore 2.12
G_M31026_IG06:
test r13, r13
je SHORT G_M31026_IG08
mov rdi, r14
test rdi, rdi
je G_M31026_IG10
- mov rdx, r15
mov rsi, r13
- mov r11, 0xD1FFAB1E ; code for System.Collections.IStructuralComparable:CompareTo(System.Object,System.Collections.IComparer):int:this+ mov rdx, r15+ mov rax, 0xD1FFAB1E ; code for System.Array:System.Collections.IStructuralComparable.CompareTo(System.Object,System.Collections.IComparer):int:this
;; size=33 bbWeight=0.50 PerfScore 1.75
G_M31026_IG07:
pop rbx
@@ -224885,7 +224885,7 @@ G_M31026_IG07:
pop r14
pop r15
pop rbp
- tail.jmp [r11]System.Collections.IStructuralComparable:CompareTo(System.Object,System.Collections.IComparer):int:this+ tail.jmp [rax]System.Array:System.Collections.IStructuralComparable.CompareTo(System.Object,System.Collections.IComparer):int:this
;; size=11 bbWeight=0.50 PerfScore 2.25
G_M31026_IG08:
mov rdi, 0xD1FFAB1E ; System.ArgumentException
@@ -224943,7 +224943,7 @@ G_M31026_IG10:
int3 ;; size=83 bbWeight=0 PerfScore 0.00
-; Total bytes of code 439, prolog size 19, PerfScore 70.28, instruction count 107, allocated bytes for code 439 (MethodHash=f38586cd) for method System.Collections.Immutable.ImmutableArray`1[System.__Canon]:System.Collections.IStructuralComparable.CompareTo(System.Object,System.Collections.IComparer):int:this (FullOpts)+; Total bytes of code 440, prolog size 19, PerfScore 70.38, instruction count 107, allocated bytes for code 440 (MethodHash=f38586cd) for method System.Collections.Immutable.ImmutableArray`1[System.__Canon]:System.Collections.IStructuralComparable.CompareTo(System.Object,System.Collections.IComparer):int:this (FullOpts)
; ============================================================

MichalPetryka · 2023-07-05T12:48:42Z

There are also some inlines that happen to be exactly the same size as before too (and more interface devirts):

@@ -234855,10 +234855,10 @@ G_M65253_IG09:
;; size=6 bbWeight=0.50 PerfScore 2.00
G_M65253_IG10:
mov rdi, r15
- mov r11, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.Internal.IDebuggerDisplay:get_Content():System.Object:this- call [r11]System.Threading.Tasks.Dataflow.Internal.IDebuggerDisplay:get_Content():System.Object:this+ mov rax, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.BatchBlock`1[System.__Canon]:get_DebuggerDisplayContent():System.Object:this+ call [rax]System.Threading.Tasks.Dataflow.BatchBlock`1[System.__Canon]:get_DebuggerDisplayContent():System.Object:this
mov rdx, rax
- ;; size=19 bbWeight=0.50 PerfScore 1.88+ ;; size=18 bbWeight=0.50 PerfScore 1.88
G_M65253_IG11:
mov rdi, r14
mov rsi, 0xD1FFAB1E ; System.Runtime.CompilerServices.DefaultInterpolatedStringHandler:AppendFormatted[System.Object](System.Object):this
@@ -234911,7 +234911,7 @@ G_M65253_IG16:
int3 ;; size=13 bbWeight=0 PerfScore 0.00
-; Total bytes of code 382, prolog size 36, PerfScore 108.16, instruction count 101, allocated bytes for code 382 (MethodHash=8f39011a) for method System.Threading.Tasks.Dataflow.BatchBlock`1+BatchBlockTargetCore[System.__Canon]:get_DebuggerDisplayContent():System.Object:this (FullOpts)+; Total bytes of code 381, prolog size 36, PerfScore 108.06, instruction count 101, allocated bytes for code 381 (MethodHash=8f39011a) for method System.Threading.Tasks.Dataflow.BatchBlock`1+BatchBlockTargetCore[System.__Canon]:get_DebuggerDisplayContent():System.Object:this (FullOpts)
; ============================================================
Unwind Info:
@@ -280039,7 +280039,7 @@ G_M61916_IG07:
call [rax]System.Threading.Tasks.Task:get_Exception():System.AggregateException:this
mov rsi, rax
mov rdi, r13
- mov r11, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.IDataflowBlock:Fault(System.Exception):this+ mov rax, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.BatchBlock`1[System.__Canon]:System.Threading.Tasks.Dataflow.IDataflowBlock.Fault(System.Exception):this
cmp dword ptr [rdi], edi
;; size=35 bbWeight=1 PerfScore 10.25
G_M61916_IG08:
@@ -280049,7 +280049,7 @@ G_M61916_IG08:
pop r14
pop r15
pop rbp
- tail.jmp [r11]System.Threading.Tasks.Dataflow.IDataflowBlock:Fault(System.Exception):this+ tail.jmp [rax]System.Threading.Tasks.Dataflow.BatchBlock`1[System.__Canon]:System.Threading.Tasks.Dataflow.IDataflowBlock.Fault(System.Exception):this
;; size=15 bbWeight=1 PerfScore 4.75
G_M61916_IG09:
mov rdi, rsi
@@ -302525,7 +302525,7 @@ G_M6956_IG07:
call [rax]System.Threading.Tasks.Task:get_Exception():System.AggregateException:this
mov rsi, rax
mov rdi, r13
- mov r11, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.IDataflowBlock:Fault(System.Exception):this+ mov rax, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.BatchedJoinBlock`2[System.__Canon,System.Nullable`1[int]]:System.Threading.Tasks.Dataflow.IDataflowBlock.Fault(System.Exception):this
cmp dword ptr [rdi], edi
;; size=35 bbWeight=1 PerfScore 10.25
G_M6956_IG08:
@@ -302535,7 +302535,7 @@ G_M6956_IG08:
pop r14
pop r15
pop rbp
- tail.jmp [r11]System.Threading.Tasks.Dataflow.IDataflowBlock:Fault(System.Exception):this+ tail.jmp [rax]System.Threading.Tasks.Dataflow.BatchedJoinBlock`2[System.__Canon,System.Nullable`1[int]]:System.Threading.Tasks.Dataflow.IDataflowBlock.Fault(System.Exception):this
;; size=15 bbWeight=1 PerfScore 4.75
G_M6956_IG09:
mov rdi, rsi
@@ -384098,7 +384098,7 @@ G_M65183_IG07:
call [rax]System.Threading.Tasks.Task:get_Exception():System.AggregateException:this
mov rsi, rax
mov rdi, r13
- mov r11, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.IDataflowBlock:Fault(System.Exception):this+ mov rax, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.BroadcastBlock`1[System.__Canon]:System.Threading.Tasks.Dataflow.IDataflowBlock.Fault(System.Exception):this
cmp dword ptr [rdi], edi
;; size=35 bbWeight=1 PerfScore 10.25
G_M65183_IG08:
@@ -384108,7 +384108,7 @@ G_M65183_IG08:
pop r14
pop r15
pop rbp
- tail.jmp [r11]System.Threading.Tasks.Dataflow.IDataflowBlock:Fault(System.Exception):this+ tail.jmp [rax]System.Threading.Tasks.Dataflow.BroadcastBlock`1[System.__Canon]:System.Threading.Tasks.Dataflow.IDataflowBlock.Fault(System.Exception):this
;; size=15 bbWeight=1 PerfScore 4.75
G_M65183_IG09:
mov rdi, rsi
@@ -417014,7 +417014,7 @@ G_M9986_IG07:
call [rax]System.Threading.Tasks.Task:get_Exception():System.AggregateException:this
mov rsi, rax
mov rdi, r13
- mov r11, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.IDataflowBlock:Fault(System.Exception):this+ mov rax, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.BufferBlock`1[System.__Canon]:System.Threading.Tasks.Dataflow.IDataflowBlock.Fault(System.Exception):this
cmp dword ptr [rdi], edi
;; size=35 bbWeight=1 PerfScore 10.25
G_M9986_IG08:
@@ -417024,7 +417024,7 @@ G_M9986_IG08:
pop r14
pop r15
pop rbp
- tail.jmp [r11]System.Threading.Tasks.Dataflow.IDataflowBlock:Fault(System.Exception):this+ tail.jmp [rax]System.Threading.Tasks.Dataflow.BufferBlock`1[System.__Canon]:System.Threading.Tasks.Dataflow.IDataflowBlock.Fault(System.Exception):this
;; size=15 bbWeight=1 PerfScore 4.75
G_M9986_IG09:
mov rdi, rsi
@@ -439687,7 +439687,7 @@ G_M7316_IG07:
call [rax]System.Threading.Tasks.Task:get_Exception():System.AggregateException:this
mov rsi, rax
mov rdi, r13
- mov r11, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.IDataflowBlock:Fault(System.Exception):this+ mov rax, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.JoinBlock`2[System.__Canon,System.Nullable`1[int]]:System.Threading.Tasks.Dataflow.IDataflowBlock.Fault(System.Exception):this
cmp dword ptr [rdi], edi
;; size=35 bbWeight=1 PerfScore 10.25
G_M7316_IG08:
@@ -439697,7 +439697,7 @@ G_M7316_IG08:
pop r14
pop r15
pop rbp
- tail.jmp [r11]System.Threading.Tasks.Dataflow.IDataflowBlock:Fault(System.Exception):this+ tail.jmp [rax]System.Threading.Tasks.Dataflow.JoinBlock`2[System.__Canon,System.Nullable`1[int]]:System.Threading.Tasks.Dataflow.IDataflowBlock.Fault(System.Exception):this
;; size=15 bbWeight=1 PerfScore 4.75
G_M7316_IG09:
mov rdi, rsi
@@ -472255,7 +472255,7 @@ G_M32213_IG07:
call [rax]System.Threading.Tasks.Task:get_Exception():System.AggregateException:this
mov rsi, rax
mov rdi, r13
- mov r11, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.IDataflowBlock:Fault(System.Exception):this+ mov rax, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.TransformBlock`2[System.__Canon,System.Nullable`1[int]]:System.Threading.Tasks.Dataflow.IDataflowBlock.Fault(System.Exception):this
cmp dword ptr [rdi], edi
;; size=35 bbWeight=1 PerfScore 10.25
G_M32213_IG08:
@@ -472265,7 +472265,7 @@ G_M32213_IG08:
pop r14
pop r15
pop rbp
- tail.jmp [r11]System.Threading.Tasks.Dataflow.IDataflowBlock:Fault(System.Exception):this+ tail.jmp [rax]System.Threading.Tasks.Dataflow.TransformBlock`2[System.__Canon,System.Nullable`1[int]]:System.Threading.Tasks.Dataflow.IDataflowBlock.Fault(System.Exception):this
;; size=15 bbWeight=1 PerfScore 4.75
G_M32213_IG09:
mov rdi, rsi
@@ -521748,7 +521748,7 @@ G_M30752_IG07:
call [rax]System.Threading.Tasks.Task:get_Exception():System.AggregateException:this
mov rsi, rax
mov rdi, r13
- mov r11, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.IDataflowBlock:Fault(System.Exception):this+ mov rax, 0xD1FFAB1E ; code for System.Threading.Tasks.Dataflow.TransformManyBlock`2[System.__Canon,System.Nullable`1[int]]:System.Threading.Tasks.Dataflow.IDataflowBlock.Fault(System.Exception):this
cmp dword ptr [rdi], edi
;; size=35 bbWeight=1 PerfScore 10.25
G_M30752_IG08:
@@ -521758,7 +521758,7 @@ G_M30752_IG08:
pop r14
pop r15
pop rbp
- tail.jmp [r11]System.Threading.Tasks.Dataflow.IDataflowBlock:Fault(System.Exception):this+ tail.jmp [rax]System.Threading.Tasks.Dataflow.TransformManyBlock`2[System.__Canon,System.Nullable`1[int]]:System.Threading.Tasks.Dataflow.IDataflowBlock.Fault(System.Exception):this
;; size=15 bbWeight=1 PerfScore 4.75
G_M30752_IG09:
mov rdi, rsi

MichalPetryka · 2023-07-07T21:06:30Z

@MihuBot

MichalPetryka · 2023-07-18T17:55:30Z

@MihuBot

JulieLeeMSFT · 2023-08-28T18:22:06Z

@MihuBot, this is a reminder to review this community PR.

MihaZupan · 2023-08-28T18:34:25Z

@JulieLeeMSFT MihuBot is just an automated tool to build PRs and collect jit-diff results, the mentions are a way to trigger it :)

JulieLeeMSFT · 2023-08-28T20:06:06Z

Then we will wait for a review from @EgorBo.

EgorBo · 2023-08-28T20:10:54Z

Then we will wait for a review from @EgorBo.

I think we already discussed this offile that we don't see a clear value (full diffs?) here and potential risks since it touches very sensitive things

MichalPetryka · 2023-09-01T20:47:16Z

I think we already discussed this offile that we don't see a clear value (full diffs?) here and potential risks since it touches very sensitive things

IIRC the final decision was to wait with this for shared generic inlining (which you were planning to improve in .Net 9).

JulieLeeMSFT · 2023-09-25T20:07:14Z

Converted to draft until it is further ready with clearer value after the shared generic inlining is done.

ghost · 2023-10-25T23:01:13Z

Draft Pull Request was automatically closed for 30 days of inactivity. Please let us know if you'd like to reopen it.

Improve updating classes for generics
ddb3824

MichalPetryka requested a review from MichalStrehovsky as a code owner June 30, 2023 22:42

ghost added area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI community-contribution Indicates that the PR has been added by a community member labels Jun 30, 2023

MihuBot mentioned this pull request Jun 30, 2023
[MichalPetryka] Improve updating classes for generics MihuBot/runtime-utils#66
Open

MihuBot mentioned this pull request Jul 5, 2023
[MichalPetryka] Improve updating classes for generics MihuBot/runtime-utils#77
Open

MichalPetryka mentioned this pull request Jul 5, 2023
Print variable types when dumping the output #88420
Merged

MihuBot mentioned this pull request Jul 7, 2023
[MichalPetryka] [X64] Improve updating classes for generics MihuBot/runtime-utils#108
Open

JulieLeeMSFT assigned EgorBo and MichalPetryka Jul 10, 2023

Merge branch 'dotnet:main' into better-generic
7faccd1

MihuBot mentioned this pull request Jul 18, 2023
[MichalPetryka] [X64] Improve updating classes for generics MihuBot/runtime-utils#138
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build-analysisBot mentioned this pull request Jul 18, 2023
Tracking issue for CI build timeouts #76454
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JulieLeeMSFT added this to the 9.0.0 milestone Aug 14, 2023

MihuBot mentioned this pull request Aug 28, 2023
[X64] [MichalPetryka] Improve updating classes for generics MihuBot/runtime-utils#167
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