Fix TailCallStress mode.

eng/pipelines/libraries/run-test-job.yml

@@ -143,10 +143,7 @@ jobs:
               - jitstress2
               - jitstress2_tiered
               - zapdisable
-              # tailcallstress currently has hundreds of failures on Linux/arm32, so disable it.
-              # Tracked by https://github.com/dotnet/runtime/issues/38892.
-              - ${{ if or(eq(parameters.osGroup, 'Windows_NT'), ne(parameters.archType, 'arm')) }}:
-                - tailcallstress
+              - tailcallstress
             ${{ if in(parameters.coreclrTestGroup, 'jitstressregs' ) }}:
               scenarios:
               - jitstressregs1

src/coreclr/src/jit/gentree.h

@@ -4201,6 +4201,7 @@ struct GenTreeCall final : public GenTree
 #define GTF_CALL_M_ALLOC_SIDE_EFFECTS      0x00400000 // GT_CALL -- this is a call to an allocator with side effects
 #define GTF_CALL_M_SUPPRESS_GC_TRANSITION  0x00800000 // GT_CALL -- suppress the GC transition (i.e. during a pinvoke) but a separate GC safe point is required.
 #define GTF_CALL_M_EXP_RUNTIME_LOOKUP      0x01000000 // GT_CALL -- this call needs to be tranformed into CFG for the dynamic dictionary expansion feature.
+#define GTF_CALL_M_STRESS_TAILCALL         0x02000000 // GT_CALL -- the call is NOT "tail" prefixed but GTF_CALL_M_EXPLICIT_TAILCALL was added because of tail call stress mode
 
     // clang-format on
 
@@ -4315,6 +4316,13 @@ struct GenTreeCall final : public GenTree
         return (gtCallMoreFlags & GTF_CALL_M_EXPLICIT_TAILCALL) != 0;
     }
 
+    // Returns true if this call didn't have an explicit tail. prefix in the IL
+    // but was marked as an explicit tail call because of tail call stress mode.
+    bool IsStressTailCall() const
+    {
+        return (gtCallMoreFlags & GTF_CALL_M_STRESS_TAILCALL) != 0;
+    }
+
     // This method returning "true" implies that tail call flowgraph morhphing has
     // performed final checks and committed to making a tail call.
     bool IsTailCall() const

src/coreclr/src/jit/importer.cpp

@@ -7526,11 +7526,13 @@ enum
     PREFIX_TAILCALL_EXPLICIT = 0x00000001, // call has "tail" IL prefix
     PREFIX_TAILCALL_IMPLICIT =
         0x00000010, // call is treated as having "tail" prefix even though there is no "tail" IL prefix
-    PREFIX_TAILCALL    = (PREFIX_TAILCALL_EXPLICIT | PREFIX_TAILCALL_IMPLICIT),
-    PREFIX_VOLATILE    = 0x00000100,
-    PREFIX_UNALIGNED   = 0x00001000,
-    PREFIX_CONSTRAINED = 0x00010000,
-    PREFIX_READONLY    = 0x00100000
+    PREFIX_TAILCALL_STRESS =
+        0x00000100, // call doesn't "tail" IL prefix but is treated as explicit because of tail call stress
+    PREFIX_TAILCALL    = (PREFIX_TAILCALL_EXPLICIT | PREFIX_TAILCALL_IMPLICIT | PREFIX_TAILCALL_STRESS),
+    PREFIX_VOLATILE    = 0x00001000,
+    PREFIX_UNALIGNED   = 0x00010000,
+    PREFIX_CONSTRAINED = 0x00100000,
+    PREFIX_READONLY    = 0x01000000
 };
 
 /********************************************************************************
@@ -8674,6 +8676,7 @@ var_types Compiler::impImportCall(OPCODE                  opcode,
     {
         const bool isExplicitTailCall = (tailCallFlags & PREFIX_TAILCALL_EXPLICIT) != 0;
         const bool isImplicitTailCall = (tailCallFlags & PREFIX_TAILCALL_IMPLICIT) != 0;
+        const bool isStressTailCall   = (tailCallFlags & PREFIX_TAILCALL_STRESS) != 0;
 
         // Exactly one of these should be true.
         assert(isExplicitTailCall != isImplicitTailCall);
@@ -8740,6 +8743,12 @@ var_types Compiler::impImportCall(OPCODE                  opcode,
                     // for in-lining.
                     call->AsCall()->gtCallMoreFlags |= GTF_CALL_M_EXPLICIT_TAILCALL;
                     JITDUMP("\nGTF_CALL_M_EXPLICIT_TAILCALL set for call [%06u]\n", dspTreeID(call));
+
+                    if (isStressTailCall)
+                    {
+                        call->AsCall()->gtCallMoreFlags |= GTF_CALL_M_STRESS_TAILCALL;
+                        JITDUMP("\nGTF_CALL_M_STRESS_TAILCALL set for call [%06u]\n", dspTreeID(call));
+                    }
                 }
                 else
                 {
@@ -14209,6 +14218,7 @@ void Compiler::impImportBlockCode(BasicBlock* block)
                                     // Stress the tailcall.
                                     JITDUMP(" (Tailcall stress: prefixFlags |= PREFIX_TAILCALL_EXPLICIT)");
                                     prefixFlags |= PREFIX_TAILCALL_EXPLICIT;
+                                    prefixFlags |= PREFIX_TAILCALL_STRESS;
                                 }
                                 else
                                 {

src/coreclr/src/jit/morph.cpp

@@ -7235,7 +7235,7 @@ GenTree* Compiler::fgMorphPotentialTailCall(GenTreeCall* call)
         // We still must check for any struct parameters and set 'hasStructParam'
         // so that we won't transform the recursive tail call into a loop.
         //
-        if (call->IsImplicitTailCall())
+        if (call->IsImplicitTailCall() || call->IsStressTailCall())
         {
             if (varDsc->lvHasLdAddrOp && !lvaIsImplicitByRefLocal(varNum))
             {
@@ -8793,7 +8793,7 @@ GenTree* Compiler::fgMorphCall(GenTreeCall* call)
         assert(!call->CanTailCall());
 
 #if FEATURE_MULTIREG_RET
-        if (fgGlobalMorph && call->HasMultiRegRetVal())
+        if (fgGlobalMorph && call->HasMultiRegRetVal() && varTypeIsStruct(call->TypeGet()))
         {
             // The tail call has been rejected so we must finish the work deferred
             // by impFixupCallStructReturn for multi-reg-returning calls and transform
@@ -8810,23 +8810,14 @@ GenTree* Compiler::fgMorphCall(GenTreeCall* call)
                 lvaGrabTemp(false DEBUGARG("Return value temp for multi-reg return (rejected tail call)."));
             lvaTable[tmpNum].lvIsMultiRegRet = true;
 
-            GenTree* assg = nullptr;
-            if (varTypeIsStruct(call->TypeGet()))
-            {
-                CORINFO_CLASS_HANDLE structHandle = call->gtRetClsHnd;
-                assert(structHandle != NO_CLASS_HANDLE);
-                const bool unsafeValueClsCheck = false;
-                lvaSetStruct(tmpNum, structHandle, unsafeValueClsCheck);
-                var_types structType = lvaTable[tmpNum].lvType;
-                GenTree*  dst        = gtNewLclvNode(tmpNum, structType);
-                assg                 = gtNewAssignNode(dst, call);
-            }
-            else
-            {
-                assg = gtNewTempAssign(tmpNum, call);
-            }
-
-            assg = fgMorphTree(assg);
+            CORINFO_CLASS_HANDLE structHandle = call->gtRetClsHnd;
+            assert(structHandle != NO_CLASS_HANDLE);
+            const bool unsafeValueClsCheck = false;
+            lvaSetStruct(tmpNum, structHandle, unsafeValueClsCheck);
+            var_types structType = lvaTable[tmpNum].lvType;
+            GenTree*  dst        = gtNewLclvNode(tmpNum, structType);
+            GenTree*  assg       = gtNewAssignNode(dst, call);
+            assg                 = fgMorphTree(assg);
 
             // Create the assignment statement and insert it before the current statement.
             Statement* assgStmt = gtNewStmt(assg, compCurStmt->GetILOffsetX());

src/coreclr/tests/issues.targets

@@ -67,9 +67,6 @@
         <ExcludeList Include="$(XunitTestBinBase)/GC/Scenarios/muldimjagary/muldimjagary/*">
             <Issue>https://github.com/dotnet/runtime/issues/5933</Issue>
         </ExcludeList>
-        <ExcludeList Include="$(XunitTestBinBase)/JIT/Regression/JitBlue/GitHub_11408/GitHub_11408/*">
-            <Issue>https://github.com/dotnet/runtime/issues/8017</Issue>
-        </ExcludeList>
         <ExcludeList Include="$(XunitTestBinBase)/baseservices/exceptions/StackTracePreserve/StackTracePreserveTests/*">
             <Issue>https://github.com/dotnet/runtime/issues/11213</Issue>
         </ExcludeList>

src/libraries/System.Collections.Concurrent/tests/ProducerConsumerCollectionTests.cs

@@ -98,7 +98,6 @@ public void Ctor_InitializeFromCollection_ContainsExpectedItems(int numItems)
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [SkipOnCoreClr("https://github.com/dotnet/runtime/issues/39398", RuntimeTestModes.TailcallStress)]
         public void Add_TakeFromAnotherThread_ExpectedItemsTaken()
         {
             IProducerConsumerCollection<int> c = CreateProducerConsumerCollection();

src/libraries/System.Drawing.Common/tests/FontTests.cs

@@ -784,7 +784,6 @@ public void SizeInPoints_Get_ReturnsExpected(GraphicsUnit unit)
         [InlineData(FontStyle.Strikeout | FontStyle.Bold | FontStyle.Italic, 255, true, "@", 700)]
         [InlineData(FontStyle.Regular, 0, false, "", 400)]
         [InlineData(FontStyle.Regular, 10, false, "", 400)]
-        [SkipOnCoreClr("https://github.com/dotnet/runtime/issues/38889", RuntimeTestModes.TailcallStress)]
         public void ToLogFont_Invoke_ReturnsExpected(FontStyle fontStyle, byte gdiCharSet, bool gdiVerticalFont, string expectedNamePrefix, int expectedWeight)
         {
             using (FontFamily family = FontFamily.GenericMonospace)
@@ -818,7 +817,6 @@ public void ToLogFont_Invoke_ReturnsExpected(FontStyle fontStyle, byte gdiCharSe
         [InlineData(TextRenderingHint.SingleBitPerPixel)]
         [InlineData(TextRenderingHint.SingleBitPerPixelGridFit)]
         [InlineData(TextRenderingHint.ClearTypeGridFit)]
-        [SkipOnCoreClr("https://github.com/dotnet/runtime/issues/38889", RuntimeTestModes.TailcallStress)]
         public void ToLogFont_InvokeGraphics_ReturnsExpected(TextRenderingHint textRenderingHint)
         {
             using (FontFamily family = FontFamily.GenericMonospace)

src/libraries/System.Net.HttpListener/tests/System.Net.HttpListener.Tests.csproj

@@ -5,7 +5,6 @@
     <TargetFrameworks>$(NetCoreAppCurrent)-Windows_NT;$(NetCoreAppCurrent)-Unix;$(NetCoreAppCurrent)-Browser;$(NetCoreAppCurrent)-OSX</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
-    <Compile Include="AssemblyInfo.cs" />
     <Compile Include="GetContextHelper.cs" />
     <Compile Include="HttpListenerFactory.cs" />
     <Compile Include="HttpListenerAuthenticationTests.cs" />

src/libraries/System.Security.Cryptography.X509Certificates/tests/RevocationTests/AiaTests.cs

@@ -42,7 +42,6 @@ public static void EmptyAiaResponseIsIgnored()
         }
 
         [Fact]
-        [SkipOnCoreClr("https://github.com/dotnet/runtime/issues/38887", RuntimeTestModes.TailcallStress)]
         public static void DisableAiaOptionWorks()
         {
             CertificateAuthority.BuildPrivatePki(

src/tests/JIT/opt/OSR/tailrecursetry.csproj

@@ -3,6 +3,10 @@
     <OutputType>Exe</OutputType>
     <DebugType />
     <Optimize>True</Optimize>
+    <!-- This test currently fails for TailcallStress. Disable for JIT stress modes until this is fixed.
+         Issue: https://github.com/dotnet/runtime/issues/35687
+    -->
+    <JitOptimizationSensitive>true</JitOptimizationSensitive>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="$(MSBuildProjectName).cs" />

src/tests/profiler/unittest/getappdomainstaticaddress.csproj

@@ -6,10 +6,6 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <CLRTestPriority>0</CLRTestPriority>
     <Optimize>true</Optimize>
-    <!-- This test currently fails for TailcallStress. Disable for JIT stress modes until this is fixed.
-         Issue: https://github.com/dotnet/runtime/issues/37117
-    -->
-    <JitOptimizationSensitive>true</JitOptimizationSensitive>
     <!-- This test provides no interesting scenarios for GCStress -->
     <GCStressIncompatible>true</GCStressIncompatible>
   </PropertyGroup>