[rcj1]

Route RuntimeTypeSystem through ExecutionManager.NonVirtualEntry2MethodDesc and remove the portable-only PrecodeStubs contract.

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[pcshrosbree]

I compared this head's reader with the merge base's on six linux-x64 dumps (mini, heap and full; R2R and JIT) from a Checked build at e2d92b2. GetMethodDescForSlot on every vtable slot of every type in the CoreLib and test-app TypeDef maps gave 33,092 identical observations, including minidump slots where both readers throw.

Nit: the description could separate temporary-entry-point validation, which now prefers PrecodeStubs when it is advertised, from the paths that go through NonVirtualEntry2MethodDesc.

Test patch (3 test files; applies to e2d92b2 with git apply; 3324/3324 pass)

diff --git a/src/native/managed/cdac/tests/UnitTests/ExecutionManager/ExecutionManagerTests.cs b/src/native/managed/cdac/tests/UnitTests/ExecutionManager/ExecutionManagerTests.cs
index b8b3d9152b9..8977d747123 100644
--- a/src/native/managed/cdac/tests/UnitTests/ExecutionManager/ExecutionManagerTests.cs
+++ b/src/native/managed/cdac/tests/UnitTests/ExecutionManager/ExecutionManagerTests.cs
@@ -1928,6 +1928,97 @@ public void NonVirtualEntry2MethodDesc_PortableEntryPoint_ReturnsOwningMethodDes
         Assert.Equal(expectedMethodDesc, target.Contracts.ExecutionManager.NonVirtualEntry2MethodDesc(new TargetCodePointer(entryPoint.Address)));
     }
 
+    // The non-portable paths of NonVirtualEntry2MethodDesc, mirroring native NonVirtualEntry2MethodDesc
+    // (src/coreclr/vm/method.cpp): jitted code resolves through the jit manager, a precode range list
+    // resolves through the precode, and an address in no range section resolves to null.
+
+    [Theory]
+    [MemberData(nameof(StdArchAllVersions))]
+    public void NonVirtualEntry2MethodDesc_JittedCode_ReturnsMethodDesc(string version, MockTarget.Architecture arch)
+    {
+        const ulong codeRangeStart = 0x0a0a_0000u;
+        const uint codeRangeSize = 0xc000u;
+        const uint methodSize = 0x450;
+        const ulong jitManagerAddress = 0x000b_ff00;
+        const ulong expectedMethodDescAddress = 0x0101_aaa0;
+
+        MockExecutionManagerBuilder emBuilder = new(version, arch, MockExecutionManagerBuilder.DefaultAllocationRange);
+        MockExecutionManagerBuilder.JittedCodeRange jittedCode = emBuilder.AllocateJittedCodeRange(codeRangeStart, codeRangeSize);
+        ulong methodStart = emBuilder.AddJittedMethod(jittedCode, methodSize, expectedMethodDescAddress).CodeAddress;
+        NibbleMapTestBuilderBase nibBuilder = emBuilder.CreateNibbleMap(codeRangeStart, codeRangeSize);
+        nibBuilder.AllocateCodeChunk(new TargetCodePointer(methodStart), methodSize);
+        MockCodeHeapListNode codeHeapListNode = emBuilder.AddCodeHeapListNode(0, codeRangeStart, codeRangeStart + codeRangeSize, codeRangeStart, nibBuilder.NibbleMapFragment.Address);
+        MockRangeSection rangeSection = emBuilder.AddRangeSection(jittedCode, jitManagerAddress, codeHeapListNode.Address);
+        _ = emBuilder.AddRangeSectionFragment(jittedCode, rangeSection.Address);
+
+        // Strict: resolving jitted code must not consult the precode decoder.
+        Mock<IPrecodeStubs> precodeStubs = new(MockBehavior.Strict);
+        Target target = CreateTarget(emBuilder, configureTarget: targetBuilder => targetBuilder
+            .AddContract<IFeatureFlags>(version: "c1")
+            .AddMockContract(precodeStubs));
+
+        Assert.Equal(
+            new TargetPointer(expectedMethodDescAddress),
+            target.Contracts.ExecutionManager.NonVirtualEntry2MethodDesc(new TargetCodePointer(methodStart)));
+    }
+
+    [Theory]
+    [MemberData(nameof(StdArchAllVersions))]
+    public void NonVirtualEntry2MethodDesc_PrecodeRangeList_ReturnsPrecodeMethodDesc(string version, MockTarget.Architecture arch)
+    {
+        TargetCodePointer precode = new(PrecodeRangeStart + 0x100);
+        TargetPointer expectedMethodDesc = new(0x0101_aaa0);
+        Mock<IPrecodeStubs> precodeStubs = new(MockBehavior.Strict);
+        precodeStubs.Setup(p => p.GetMethodDescFromStubAddress(precode)).Returns(expectedMethodDesc);
+
+        Target target = CreatePrecodeRangeListTarget(version, arch, precodeStubs);
+
+        Assert.Equal(expectedMethodDesc, target.Contracts.ExecutionManager.NonVirtualEntry2MethodDesc(precode));
+    }
+
+    [Theory]
+    [MemberData(nameof(StdArchAllVersions))]
+    public void NonVirtualEntry2MethodDesc_RangeListAddressThatIsNotAPrecode_ReturnsNull(string version, MockTarget.Architecture arch)
+    {
+        TargetCodePointer notAPrecode = new(PrecodeRangeStart + 0x100);
+        Mock<IPrecodeStubs> precodeStubs = new(MockBehavior.Strict);
+        precodeStubs.Setup(p => p.GetMethodDescFromStubAddress(notAPrecode)).Throws(new InvalidOperationException("Invalid precode type"));
+
+        Target target = CreatePrecodeRangeListTarget(version, arch, precodeStubs);
+
+        Assert.Equal(TargetPointer.Null, target.Contracts.ExecutionManager.NonVirtualEntry2MethodDesc(notAPrecode));
+    }
+
+    [Theory]
+    [MemberData(nameof(StdArchAllVersions))]
+    public void NonVirtualEntry2MethodDesc_AddressInNoRangeSection_ReturnsNullWithoutDecoding(string version, MockTarget.Architecture arch)
+    {
+        // Strict with no setups: native returns NULL here without reading the address as a precode.
+        Mock<IPrecodeStubs> precodeStubs = new(MockBehavior.Strict);
+
+        Target target = CreatePrecodeRangeListTarget(version, arch, precodeStubs);
+
+        Assert.Equal(TargetPointer.Null, target.Contracts.ExecutionManager.NonVirtualEntry2MethodDesc(new TargetCodePointer(PrecodeRangeStart + PrecodeRangeSize + 0x100)));
+    }
+
+    private const ulong PrecodeRangeStart = 0x0b0b_0000u;
+    private const uint PrecodeRangeSize = 0x1000u;
+
+    private static Target CreatePrecodeRangeListTarget(string version, MockTarget.Architecture arch, Mock<IPrecodeStubs> precodeStubs)
+    {
+        const ulong jitManagerAddress = 0x000b_ff00;
+        const int stubCodeBlockKindFixupPrecode = 4; // STUB_CODE_BLOCK_FIXUPPRECODE
+
+        MockExecutionManagerBuilder emBuilder = new(version, arch, MockExecutionManagerBuilder.DefaultAllocationRange);
+        MockExecutionManagerBuilder.JittedCodeRange precodeRange = emBuilder.AllocateJittedCodeRange(PrecodeRangeStart, PrecodeRangeSize);
+        MockRangeSection rangeSection = emBuilder.AddRangeListRangeSection(precodeRange, jitManagerAddress, stubCodeBlockKindFixupPrecode);
+        _ = emBuilder.AddRangeSectionFragment(precodeRange, rangeSection.Address);
+
+        return CreateTarget(emBuilder, configureTarget: targetBuilder => targetBuilder
+            .AddContract<IFeatureFlags>(version: "c1")
+            .AddMockContract(precodeStubs));
+    }
+
     private sealed class PortableEntryPointFixture
     {
         public required Target Target { get; init; }
diff --git a/src/native/managed/cdac/tests/UnitTests/MethodDescTests.cs b/src/native/managed/cdac/tests/UnitTests/MethodDescTests.cs
index c5971f3370a..c0871c9a158 100644
--- a/src/native/managed/cdac/tests/UnitTests/MethodDescTests.cs
+++ b/src/native/managed/cdac/tests/UnitTests/MethodDescTests.cs
@@ -77,7 +77,8 @@ private static uint GetMethodDescBaseSize(MockDescriptors.MockMethodDescriptorsB
     private static IRuntimeTypeSystem CreateRuntimeTypeSystemContract(
         MockTarget.Architecture arch,
         Action<MockDescriptors.MockMethodDescriptorsBuilder> configure,
-        Mock<IExecutionManager>? mockExecutionManager = null)
+        Mock<IExecutionManager>? mockExecutionManager = null,
+        Action<TestPlaceholderTarget.Builder>? configureTarget = null)
     {
         var targetBuilder = new TestPlaceholderTarget.Builder(arch);
         MockDescriptors.RuntimeTypeSystem rtsBuilder = new(targetBuilder.MemoryBuilder);
@@ -87,15 +88,15 @@ private static IRuntimeTypeSystem CreateRuntimeTypeSystemContract(
         configure(methodDescBuilder);
 
         mockExecutionManager ??= new Mock<IExecutionManager>();
-        var target = targetBuilder
+        targetBuilder
             .AddTypes(CreateContractTypes(methodDescBuilder))
             .AddGlobals(CreateContractGlobals(methodDescBuilder))
             .AddContract<IRuntimeTypeSystem>(version: "c1")
             .AddContract<ILoader>(version: "c1")
             .AddMockContract(new Mock<IPlatformMetadata>())
-            .AddMockContract(mockExecutionManager)
-            .Build();
-        return target.Contracts.RuntimeTypeSystem;
+            .AddMockContract(mockExecutionManager);
+        configureTarget?.Invoke(targetBuilder);
+        return targetBuilder.Build().Contracts.RuntimeTypeSystem;
     }
 
     [Theory]
@@ -957,6 +958,122 @@ public void Validation_NativeCodeSlot_PrecodeFallback_WrongMethodDesc_Fails(Mock
         Assert.Throws<ArgumentException>(() => rts.GetMethodDescHandle(methodDescAddress));
     }
 
+    // A populated vtable slot resolves through ExecutionManager.NonVirtualEntry2MethodDesc, as in native
+    // MethodTable::GetMethodDescForSlot_NoThrow, whatever kind of entry point the slot holds.
+    [Theory]
+    [ClassData(typeof(MockTarget.StdArch))]
+    public void GetMethodDescForSlot_PopulatedVtableSlot_ResolvesThroughNonVirtualEntry2MethodDesc(MockTarget.Architecture arch)
+    {
+        TargetCodePointer precodeEntryPoint = new(0x0789_ab00);
+        TargetCodePointer jittedEntryPoint = new(0x0789_cd00);
+        TargetPointer precodeMethodDesc = new(0x0101_aaa0);
+        TargetPointer jittedMethodDesc = new(0x0101_bbb0);
+        TargetPointer methodTable = TargetPointer.Null;
+        Mock<IExecutionManager> mockExecutionManager = new();
+        mockExecutionManager.Setup(em => em.NonVirtualEntry2MethodDesc(precodeEntryPoint)).Returns(precodeMethodDesc);
+        mockExecutionManager.Setup(em => em.NonVirtualEntry2MethodDesc(jittedEntryPoint)).Returns(jittedMethodDesc);
+
+        IRuntimeTypeSystem rts = CreateRuntimeTypeSystemContract(arch, methodDescBuilder =>
+        {
+            MockDescriptors.RuntimeTypeSystem rtsBuilder = methodDescBuilder.RTSBuilder;
+            MockEEClass eeClass = rtsBuilder.AddEEClass(string.Empty);
+            eeClass.NumNonVirtualSlots = 0;
+            MockMethodTable mt = rtsBuilder.AddMethodTableWithVtable(string.Empty, [precodeEntryPoint.Value, jittedEntryPoint.Value]);
+            mt.BaseSize = rtsBuilder.Builder.TargetTestHelpers.ObjectBaseSize;
+            eeClass.MethodTable = mt.Address;
+            mt.EEClassOrCanonMT = eeClass.Address;
+            methodTable = mt.Address;
+        }, mockExecutionManager);
+
+        ITypeHandle typeHandle = rts.GetTypeHandle(methodTable);
+        Assert.Equal(precodeMethodDesc, rts.GetMethodDescForSlot(typeHandle, 0));
+        Assert.Equal(jittedMethodDesc, rts.GetMethodDescForSlot(typeHandle, 1));
+    }
+
+    public static IEnumerable<object[]> TemporaryEntryPointValidationData()
+    {
+        foreach (object[] arch in new MockTarget.StdArch())
+        {
+            foreach (bool portableEntrypoints in new[] { false, true })
+            {
+                foreach (bool resolvesToSelf in new[] { true, false })
+                {
+                    yield return [arch[0], portableEntrypoints, resolvesToSelf];
+                }
+            }
+        }
+    }
+
+    // ValidateMethodDescPointer requires a MethodDesc's temporary entry point to resolve back to it.
+    // Without portable entry points it decodes the precode directly, like the legacy DAC's DacValidateMD
+    // (MethodDesc::GetMethodDescFromPrecode), so it does not depend on the ExecutionManager range lookup.
+    // With portable entry points no PrecodeStubs contract is advertised and NonVirtualEntry2MethodDesc is used.
+    [Theory]
+    [MemberData(nameof(TemporaryEntryPointValidationData))]
+    public void Validation_TemporaryEntryPoint_MustResolveToMethodDesc(MockTarget.Architecture arch, bool portableEntrypoints, bool resolvesToSelf)
+    {
+        TargetPointer methodDescAddress = TargetPointer.Null;
+        TargetCodePointer temporaryEntryPoint = new(0x0789_abc0);
+        TargetPointer otherMethodDesc = new(0xDEAD_BEE0);
+        Mock<IExecutionManager> mockExecutionManager = new();
+        Mock<IPrecodeStubs> mockPrecodeStubs = new(MockBehavior.Strict);
+        Target.TypeInfo codeDataType = default;
+
+        IRuntimeTypeSystem rts = CreateRuntimeTypeSystemContract(arch, methodDescBuilder =>
+        {
+            TargetTestHelpers helpers = methodDescBuilder.Builder.TargetTestHelpers;
+            TargetPointer methodTable = AddMethodTable(methodDescBuilder.RTSBuilder);
+            byte chunkSize = (byte)(methodDescBuilder.MethodDescLayout.Size / methodDescBuilder.MethodDescAlignment);
+            MockMethodDescChunk chunk = methodDescBuilder.AddMethodDescChunk(string.Empty, chunkSize);
+            chunk.MethodTable = methodTable.Value;
+            chunk.Size = chunkSize;
+            chunk.Count = 1;
+
+            // MethodDescCodeData holds only the temporary entry point here.
+            codeDataType = new Target.TypeInfo
+            {
+                Fields = new Dictionary<string, Target.FieldInfo> { [nameof(Data.MethodDescCodeData.TemporaryEntryPoint)] = new() { Offset = 0 } },
+                Size = (uint)helpers.PointerSize,
+            };
+            MockMemorySpace.HeapFragment codeData = methodDescBuilder.Builder.CreateAllocator(0x0444_0000, 0x0444_1000)
+                .Allocate((ulong)helpers.PointerSize, "MethodDescCodeData");
+            helpers.WritePointer(codeData.Data.AsSpan(), temporaryEntryPoint);
+
+            MockMethodDesc methodDesc = chunk.GetMethodDescAtChunkIndex(0, methodDescBuilder.MethodDescLayout);
+            methodDesc.Flags = (ushort)MethodClassification.IL;
+            methodDesc.EntryPointFlags = (byte)MethodDescFlags_1.MethodDescEntryPointFlags.TemporaryEntryPointAssigned;
+            methodDesc.CodeData = codeData.Address;
+            methodDescAddress = new TargetPointer(methodDesc.Address);
+        }, mockExecutionManager, targetBuilder =>
+        {
+            targetBuilder.AddTypes(new Dictionary<DataType, Target.TypeInfo> { [DataType.MethodDescCodeData] = codeDataType });
+            if (!portableEntrypoints)
+                targetBuilder.AddMockContract(mockPrecodeStubs);
+        });
+
+        TargetPointer resolved = resolvesToSelf ? methodDescAddress : otherMethodDesc;
+        if (portableEntrypoints)
+        {
+            mockExecutionManager.Setup(em => em.NonVirtualEntry2MethodDesc(temporaryEntryPoint)).Returns(resolved);
+        }
+        else
+        {
+            // The ExecutionManager reports nothing for this address (for example, its range section is not in a
+            // minidump); validation must still succeed through the precode.
+            mockExecutionManager.Setup(em => em.NonVirtualEntry2MethodDesc(temporaryEntryPoint)).Returns(TargetPointer.Null);
+            mockPrecodeStubs.Setup(p => p.GetMethodDescFromStubAddress(temporaryEntryPoint)).Returns(resolved);
+        }
+
+        if (resolvesToSelf)
+        {
+            Assert.Equal(methodDescAddress, rts.GetMethodDescHandle(methodDescAddress).Address);
+        }
+        else
+        {
+            Assert.Throws<ArgumentException>(() => rts.GetMethodDescHandle(methodDescAddress));
+        }
+    }
+
     private static TargetPointer AddMethodTable(MockDescriptors.RuntimeTypeSystem rtsBuilder, ushort numVirtuals = 5)
     {
         MockEEClass eeClass = rtsBuilder.AddEEClass(string.Empty);
diff --git a/src/native/managed/cdac/tests/UnitTests/MockDescriptors/MockDescriptors.RuntimeTypeSystem.cs b/src/native/managed/cdac/tests/UnitTests/MockDescriptors/MockDescriptors.RuntimeTypeSystem.cs
index 81b04ccfe7c..1b865fac4e6 100644
--- a/src/native/managed/cdac/tests/UnitTests/MockDescriptors/MockDescriptors.RuntimeTypeSystem.cs
+++ b/src/native/managed/cdac/tests/UnitTests/MockDescriptors/MockDescriptors.RuntimeTypeSystem.cs
@@ -658,6 +658,32 @@ private TView Add<TView>(Layout<TView> layout, ulong size, string name)
             return layout.Create(fragment.Data.AsMemory(), fragment.Address);
         }
 
+        /// <summary>
+        /// Allocates a method table followed by one vtable indirection and its chunk of virtual slots
+        /// (MethodTable::GetSlotPtrRaw: the indirections start immediately after the MethodTable).
+        /// Sets <c>NumVirtuals</c> to the number of slots given.
+        /// </summary>
+        internal MockMethodTable AddMethodTableWithVtable(string name, ulong[] vtableSlots)
+        {
+            const int SlotsPerIndirection = 8;
+            if (vtableSlots.Length > SlotsPerIndirection)
+                throw new ArgumentOutOfRangeException(nameof(vtableSlots));
+
+            int pointerSize = Builder.TargetTestHelpers.PointerSize;
+            int indirectionOffset = MethodTableLayout.Size;
+            int chunkOffset = indirectionOffset + pointerSize;
+            MockMemorySpace.HeapFragment fragment = TypeSystemAllocator.Allocate(
+                (ulong)(chunkOffset + SlotsPerIndirection * pointerSize), $"MethodTable+vtable '{name}'");
+
+            Builder.TargetTestHelpers.WritePointer(fragment.Data.AsSpan(indirectionOffset, pointerSize), fragment.Address + (ulong)chunkOffset);
+            for (int i = 0; i < vtableSlots.Length; i++)
+                Builder.TargetTestHelpers.WritePointer(fragment.Data.AsSpan(chunkOffset + i * pointerSize, pointerSize), vtableSlots[i]);
+
+            MockMethodTable mt = MethodTableLayout.Create(fragment.Data.AsMemory(0, MethodTableLayout.Size), fragment.Address);
+            mt.NumVirtuals = (ushort)vtableSlots.Length;
+            return mt;
+        }
+
         /// <summary>
         /// Allocates a method table together with a CGCDesc immediately before it in memory.
         /// </summary>

Note

This review was drafted with AI assistance (Anthropic Claude, reviewed with OpenAI Codex). The builds, dumps and test runs behind it were run locally.

[rcj1]

/ba-g unrelated stress fails

[pcshrosbree]

Follow-up with the tests: #135470