[NativeAOT-LLVM] Stop generating catch funclets #2399

SingleAccretion · 2023-09-09T18:28:10Z

After #2374 native unwinding will only be performed for second-pass handlers, hence, we do not actually need true funclets for second-pass handlers.

This change is the starting point for realizing the benefits of removing this requirement, those being tighter and smaller LLVM, better code quality and better debugging support.

For now, I only did the mechanical "move the code around" part. In particular:

We now rewrite the funclet info to match our view of the code to be generated.
We eagerly initialize LLVM blocks and move the "generate EH dispatch" code from the end of compilation to its beginning. This is mainly because the LLVM funclet tree requires catchpad instructions for the enclosing handlers to already be generated by the time we're generating handler bodies.
Supporting changes like tracking the handler index in the emit context (since now there is no 1-1 correspondence between handlers and funclets).

What is not included in this change:

Not generating funclets for faults.
Not forcing locals not live into true funclets to the shadow stack.

Diffs from change come mainly from the first commit (generating LLVM blocks in layout order) and are basically LLVM noise, though overall positive. Diffs for the second commit are minimal (-400 bytes code).

Total bytes of base: 3156378
Total bytes of diff: 3154266
Total bytes of delta: -2112 (-0.07% % of base)
Average relative delta: -0.31%
    diff is an improvement
    average relative diff is an improvement

Top method regressions (percentages):
           7 (15.56% of base) : 2834.dasm - S_P_CoreLib_System_Runtime_GCStress__Initialize
          13 (10.92% of base) : 2459.dasm - S_P_CoreLib_System_Collections_Generic_Dictionary_2<System___Canon__IntPtr>__TryGetValue
          13 (10.92% of base) : 2065.dasm - S_P_CoreLib_System_Collections_Generic_Dictionary_2<System___Canon__Bool>__TryGetValue
           7 (10.45% of base) : 2839.dasm - HelloWasm_Program___CallMe
           8 (10.26% of base) : 2443.dasm - S_P_CoreLib_System_Number_BigInteger__ToUInt64
           2 (10.00% of base) : 2568.dasm - S_P_TypeLoader_Internal_TypeSystem_LockFreeObjectInterner__ConvertIntPtrToValue
           6 ( 9.84% of base) : 1873.dasm - S_P_CoreLib_System_Number_BigInteger__DivideGuessTooBig
          96 ( 8.83% of base) : 1073.dasm - S_P_CoreLib_System_Reflection_Runtime_TypeInfos_RuntimeTypeInfo__get_ImplementedInterfaces
          58 ( 8.02% of base) : 2078.dasm - S_P_CoreLib_System_Globalization_CultureData__GetCultureData
          89 ( 6.96% of base) : 1656.dasm - S_P_CoreLib_Internal_Reflection_Extensions_NonPortable_CustomAttributeInstantiator__Convert
          13 ( 6.91% of base) : 2052.dasm - S_P_CoreLib_System_Number__MatchChars
           5 ( 6.33% of base) : 2771.dasm - S_P_TypeLoader_System_Collections_Generic_LowLevelDictionary_2<S_P_CoreLib_Internal_Runtime_TypeManagerHandle__System___Canon>__GetBucket
           5 ( 6.33% of base) : 1192.dasm - S_P_TypeLoader_System_Collections_Generic_LowLevelDictionary_2<S_P_CoreLib_Internal_Runtime_TypeManagerHandle__Int32>__GetBucket
           7 ( 6.03% of base) : 1507.dasm - String__Substring
          76 ( 5.77% of base) : 2421.dasm - S_P_CoreLib_System_Threading_WaitSubsystem_ThreadWaitInfo__Wait
          18 ( 5.71% of base) : 2349.dasm - HelloWasm_Program__TestFilter
          11 ( 5.67% of base) : 1104.dasm - S_P_TypeLoader_Internal_Runtime_TypeLoader_RuntimeSignatureHelper__GetModuleInfo
           2 ( 5.56% of base) : 3004.dasm - S_P_CoreLib_System_Reflection_ParameterInfo__IsDefined
          12 ( 5.56% of base) : 2112.dasm - S_P_CoreLib_System_Globalization_CultureInfo__GetUserDefaultCulture
           2 ( 5.41% of base) : 2903.dasm - S_P_CoreLib_System_ArgumentNullException__ThrowIfNull

Top methods only present in diff:
         110 (     ∞ of base) : 3101.dasm - HelloWasm_Program__TestVirtualUnwindStackNoPopOnNestedUnwindingCatch$F1_Finally
         112 (     ∞ of base) : 3082.dasm - HelloWasm_Program___TestVirtualUnwindStackNoPopOnThrow_g__TestVirtualUnwindStackNoPopOnThrow_NotInTryCatch_229_0$F1_Finally
         105 (     ∞ of base) : 3083.dasm - HelloWasm_Program___TestVirtualUnwindStackNoPopOnUnwindingCatch_g__TestVirtualUnwindStackNoPopOnUnwindingCatch_NotInTryCatch_232_1$F1_Finally
         105 (     ∞ of base) : 3084.dasm - HelloWasm_Program___TestVirtualUnwindStackNoPopOnUnwindingFault_g__TestVirtualUnwindStackNoPopOnUnwindingFault_NotInTryCatch_237_1$F1_Finally
          74 (     ∞ of base) : 3085.dasm - HelloWasm_Program___TestExactUncontainedNestedDispatchIntraFrame_g__TestExactUncontainedNestedDispatchIntraFrame_Fault_246_1$F1_Finally
          98 (     ∞ of base) : 3086.dasm - HelloWasm_Program__TryFinally$F1_Finally
          29 (     ∞ of base) : 3087.dasm - S_P_CoreLib_System_Globalization_CultureInfo__GetCultureInfo_0$F2_Finally
          94 (     ∞ of base) : 3088.dasm - HelloWasm_Program___TestDeepContainedNestedDispatchIntraFrame_g__TestDeepContainedNestedDispatchSingleFrame_TryThree_242_3$F1_Finally
         151 (     ∞ of base) : 3089.dasm - HelloWasm_Program___TestExpandingUncontainedNestedDispatchIntraFrame_g__TestExpandingUncontainedNestedDispatchIntraFrame_NestedThrow_248_1$F1_Finally
          25 (     ∞ of base) : 3080.dasm - S_P_TypeLoader_Internal_Runtime_TypeLoader_TypeLoaderEnvironment__EnsureTypeHandleForType$F1_Finally
         162 (     ∞ of base) : 3090.dasm - HelloWasm_Program___TestClippingUncontainedNestedDispatchIntraFrame_g__TestClippingUncontainedNestedDispatchIntrarame_NestedThrow_247_1$F1_Finally
         370 (     ∞ of base) : 3092.dasm - HelloWasm_Program__TestDeepUncontainedNestedDispatchSingleFrame$F1_Finally
         141 (     ∞ of base) : 3093.dasm - HelloWasm_Program__TestDeepUncontainedNestedDispatchSingleFrame$F3_Finally
         117 (     ∞ of base) : 3094.dasm - HelloWasm_Program__TestExpandingUncontainedNestedDispatchSingleFrame$F1_Finally
         110 (     ∞ of base) : 3100.dasm - HelloWasm_Program__TestVirtualUnwindStackNoPopOnNestedUnwindingFault$F1_Finally
         128 (     ∞ of base) : 3095.dasm - HelloWasm_Program__TestClippingUncontainedNestedDispatchSingleFrame$F1_Finally
         123 (     ∞ of base) : 3096.dasm - HelloWasm_Program__TestExactUncontainedNestedDispatchSingleFrame$F1_Finally
         453 (     ∞ of base) : 3097.dasm - HelloWasm_Program__TestDeepContainedNestedDispatchSingleFrame$F1_Finally
         304 (     ∞ of base) : 3098.dasm - HelloWasm_Program__TestDeepContainedNestedDispatchSingleFrame$F3_Finally
         167 (     ∞ of base) : 3099.dasm - HelloWasm_Program__TestContainedNestedDispatchSingleFrame$F1_Finally

Top method improvements (percentages):
        -102 (-70.83% of base) : 2605.dasm - HelloWasm_Program__TestDeepUncontainedNestedDispatchSingleFrame$F2_Finally
         -17 (-16.67% of base) : 2252.dasm - S_P_CoreLib_System_Reflection_MemberFilter__GetThunk
         -17 (-16.67% of base) : 1671.dasm - S_P_CoreLib_System_Func_2<S_P_CoreLib_System_Reflection_Runtime_Assemblies_NativeFormat_NativeFormatRuntimeAssembly_RuntimeAssemblyKey__System___Canon>__GetThunk
         -17 (-16.67% of base) : 1670.dasm - S_P_CoreLib_System_Comparison_1<S_P_CoreLib_Internal_Runtime_CompilerServices_UnboxingStubTargetsMap_UnboxingStubTargetMapping>__GetThunk
         -17 (-16.67% of base) : 1669.dasm - S_P_CoreLib_System_Comparison_1<S_P_Reflection_Execution_Internal_Reflection_Execution_ExecutionEnvironmentImplementation_FunctionPointerOffsetPair>__GetThunk
         -17 (-16.67% of base) : 1945.dasm - S_P_CoreLib_System_Reflection_Runtime_MethodInfos_CustomMethodInvokerAction__GetThunk
         -17 (-16.67% of base) : 1471.dasm - S_P_CoreLib_System_Func_5<System___Canon__System___Canon__System___Canon__Bool__System___Canon>__GetThunk
         -17 (-16.67% of base) : 1479.dasm - S_P_CoreLib_System_Func_2<System___Canon__System___Canon>__GetThunk
         -17 (-16.67% of base) : 1473.dasm - S_P_CoreLib_System_Runtime_CompilerServices_ConditionalWeakTable_2_CreateValueCallback<System___Canon__System___Canon>__GetThunk
         -17 (-16.67% of base) : 1481.dasm - S_P_CoreLib_System_Func_2<System___Canon__S_P_Reflection_Execution_Internal_Reflection_Execution_ExecutionEnvironmentImplementation_FunctionPointersToOffsets>__GetThunk
         -17 (-16.67% of base) : 1482.dasm - S_P_CoreLib_System_Func_2<System___Canon__Bool>__GetThunk
         -17 (-16.67% of base) : 1483.dasm - HelloWasm_Stack_1_StackDelegate<System___Canon>__GetThunk
         -17 (-16.67% of base) : 1696.dasm - S_P_CoreLib_System_Func_2<Char__Bool>__GetThunk
         -17 (-16.67% of base) : 1488.dasm - S_P_CoreLib_System_Predicate_1<System___Canon>__GetThunk
         -14 (-15.73% of base) : 2250.dasm - S_P_CoreLib_System_Reflection_Runtime_TypeInfos_RuntimeConstructedGenericTypeInfo_TryGetConstructedGenericTypeDelegate__GetThunk
         -14 (-15.73% of base) : 1679.dasm - S_P_CoreLib_System_Func_1<Int32>__GetThunk
         -14 (-15.73% of base) : 2261.dasm - S_P_CoreLib_System_Runtime_RuntimeObjectFactory__GetThunk
         -14 (-15.73% of base) : 2538.dasm - S_P_CoreLib_System_Action__GetThunk
         -11 (-14.86% of base) : 2263.dasm - HelloWasm_Program_DelegateToCallFromUnmanaged__GetThunk
         -11 (-14.86% of base) : 1695.dasm - S_P_CoreLib_System_Buffers_SpanAction_2<Char__IntPtr>__GetThunk

Top methods only present in base:
        -303 (-100.00% of base) : 2619.dasm - HelloWasm_Program__TestDeepContainedNestedDispatchSingleFrame$F5_Finally
         -98 (-100.00% of base) : 1365.dasm - HelloWasm_Program__TryFinally$F2_Finally
        -113 (-100.00% of base) : 2624.dasm - HelloWasm_Program__TestVirtualUnwindStackNoPopOnNestedUnwindingFault$F4_Finally
        -453 (-100.00% of base) : 2618.dasm - HelloWasm_Program__TestDeepContainedNestedDispatchSingleFrame$F9_Finally
         -75 (-100.00% of base) : 1363.dasm - HelloWasm_Program___TestExactUncontainedNestedDispatchIntraFrame_g__TestExactUncontainedNestedDispatchIntraFrame_Fault_246_1$F3_Finally
        -163 (-100.00% of base) : 2416.dasm - HelloWasm_Program___TestClippingUncontainedNestedDispatchIntraFrame_g__TestClippingUncontainedNestedDispatchIntrarame_NestedThrow_247_1$F3_Finally
        -152 (-100.00% of base) : 2414.dasm - HelloWasm_Program___TestExpandingUncontainedNestedDispatchIntraFrame_g__TestExpandingUncontainedNestedDispatchIntraFrame_NestedThrow_248_1$F3_Finally
        -124 (-100.00% of base) : 2615.dasm - HelloWasm_Program__TestExactUncontainedNestedDispatchSingleFrame$F3_Finally
        -106 (-100.00% of base) : 1361.dasm - HelloWasm_Program___TestVirtualUnwindStackNoPopOnUnwindingFault_g__TestVirtualUnwindStackNoPopOnUnwindingFault_NotInTryCatch_237_1$F3_Finally
        -113 (-100.00% of base) : 2627.dasm - HelloWasm_Program__TestVirtualUnwindStackNoPopOnNestedUnwindingCatch$F4_Finally
        -131 (-100.00% of base) : 2613.dasm - HelloWasm_Program__TestClippingUncontainedNestedDispatchSingleFrame$F3_Finally
        -120 (-100.00% of base) : 2611.dasm - HelloWasm_Program__TestExpandingUncontainedNestedDispatchSingleFrame$F3_Finally
        -106 (-100.00% of base) : 1359.dasm - HelloWasm_Program___TestVirtualUnwindStackNoPopOnUnwindingCatch_g__TestVirtualUnwindStackNoPopOnUnwindingCatch_NotInTryCatch_232_1$F3_Finally
         -42 (-100.00% of base) : 2606.dasm - HelloWasm_Program__TestDeepUncontainedNestedDispatchSingleFrame$F4_Finally
         -29 (-100.00% of base) : 1737.dasm - S_P_CoreLib_System_Globalization_CultureInfo__GetCultureInfo_0$F1_Finally
        -113 (-100.00% of base) : 1357.dasm - HelloWasm_Program___TestVirtualUnwindStackNoPopOnThrow_g__TestVirtualUnwindStackNoPopOnThrow_NotInTryCatch_229_0$F4_Finally
         -97 (-100.00% of base) : 1840.dasm - HelloWasm_Program___TestDeepContainedNestedDispatchIntraFrame_g__TestDeepContainedNestedDispatchSingleFrame_TryThree_242_3$F2_Finally
        -151 (-100.00% of base) : 1269.dasm - S_P_CoreLib_Interop_Sys__ReadLink_0$F1_Finally
         -25 (-100.00% of base) : 1107.dasm - S_P_TypeLoader_Internal_Runtime_TypeLoader_TypeLoaderEnvironment__EnsureTypeHandleForType$F2_Finally
        -373 (-100.00% of base) : 2604.dasm - HelloWasm_Program__TestDeepUncontainedNestedDispatchSingleFrame$F5_Finally

2102 total methods with Code Size differences (1202 improved, 900 regressed)

SingleAccretion · 2023-09-09T18:39:32Z

src/coreclr/jit/llvmcodegen.cpp

+            // We have the "unwind" block. Since we're generating things from outer to inner, we already have its
+            // "local" counterpart; it will be the next block.
+            outerUnwindLlvmBlock = outerUnwindLlvmBlock->getNextNode();
+            assert(outerUnwindLlvmBlock != nullptr);


I have switched the terminology away from "dispatch" to "unwind" in a bunch of places because it better represents that this code is involved in handling the second pass ("unwinding the stack") as opposed to the first pass ("dispatching the exception") like it was originally.

SingleAccretion · 2023-09-13T17:33:38Z

@dotnet/nativeaot-llvm

Since it handles adding the operand bundles.

yowl

LGTM, module one typo

src/coreclr/jit/llvmcodegen.cpp

Co-authored-by: yowl <[email protected]>

jkotas · 2023-10-03T00:55:18Z

@SingleAccretion Could you please resolve the conflict?

SingleAccretion · 2023-10-03T09:59:26Z

@jkotas Done.

jkotas · 2023-10-03T10:21:01Z

Thank you

SingleAccretion commented Sep 9, 2023

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SingleAccretion force-pushed the No-Catch-Funclets branch from 687a601 to e283686 Compare September 9, 2023 20:27

SingleAccretion mentioned this pull request Sep 9, 2023

[NativeAOT-LLVM] Exception handling: outstanding tasks #2169

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SingleAccretion force-pushed the No-Catch-Funclets branch 7 times, most recently from f1a5ba3 to ab1bbdf Compare September 13, 2023 16:27

SingleAccretion marked this pull request as ready for review September 13, 2023 17:33

SingleAccretion force-pushed the No-Catch-Funclets branch from ab1bbdf to ec820c6 Compare September 14, 2023 21:47

jkotas added the area-NativeAOT-LLVM LLVM generation for Native AOT compilation (including Web Assembly) label Sep 15, 2023

SingleAccretion force-pushed the No-Catch-Funclets branch from ec820c6 to d6a0321 Compare September 15, 2023 21:25

SingleAccretion added 5 commits September 18, 2023 22:36

wasmjit-diff.ps1 fix

2f2d2fb

Initialize block eagerly

91ee979

Initial version

ee90723

Fix the use-after-free bug

36a6d1c

Use emitCallOrInvoke for all calls

8f157fe

Since it handles adding the operand bundles.

SingleAccretion force-pushed the No-Catch-Funclets branch from d6a0321 to 8f157fe Compare September 18, 2023 20:38

yowl approved these changes Oct 3, 2023

View reviewed changes

src/coreclr/jit/llvmcodegen.cpp Outdated Show resolved Hide resolved

Update src/coreclr/jit/llvmcodegen.cpp

f176072

Co-authored-by: yowl <[email protected]>

Merge branch 'feature/NativeAOT-LLVM' into No-Catch-Funclets

a049552

jkotas merged commit 4940b58 into dotnet:feature/NativeAOT-LLVM Oct 3, 2023
11 checks passed

SingleAccretion mentioned this pull request Nov 28, 2023

[NativeAOT-LLVM] Do not use funclets for faults #2443

Merged

SingleAccretion deleted the No-Catch-Funclets branch December 1, 2023 19:50

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[NativeAOT-LLVM] Stop generating catch funclets #2399

[NativeAOT-LLVM] Stop generating catch funclets #2399

SingleAccretion commented Sep 9, 2023 •

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SingleAccretion commented Sep 13, 2023

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SingleAccretion commented Oct 3, 2023

jkotas commented Oct 3, 2023

[NativeAOT-LLVM] Stop generating catch funclets #2399

[NativeAOT-LLVM] Stop generating catch funclets #2399

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