Fixes issue dotnet#51612 (dotnet#52231)

* Add regression test for dotnet#51612

* Allocate a dummy local when an inlinee needs GSCookie but the root method does not in src/coreclr/jit/fginline.cpp

src/coreclr/jit/fginline.cpp

@@ -1343,7 +1343,6 @@ void Compiler::fgInsertInlineeBlocks(InlineInfo* pInlineInfo)
     compLocallocOptimized |= InlineeCompiler->compLocallocOptimized;
     compQmarkUsed |= InlineeCompiler->compQmarkUsed;
     compUnsafeCastUsed |= InlineeCompiler->compUnsafeCastUsed;
-    compNeedsGSSecurityCookie |= InlineeCompiler->compNeedsGSSecurityCookie;
     compGSReorderStackLayout |= InlineeCompiler->compGSReorderStackLayout;
     compHasBackwardJump |= InlineeCompiler->compHasBackwardJump;
 
@@ -1398,6 +1397,15 @@ void Compiler::fgInsertInlineeBlocks(InlineInfo* pInlineInfo)
     }
 #endif
 
+    // If an inlinee needs GS cookie we need to make sure that the cookie will not be allocated at zero stack offset.
+    // Note that if the root method needs GS cookie then this has already been taken care of.
+    if (!getNeedsGSSecurityCookie() && InlineeCompiler->getNeedsGSSecurityCookie())
+    {
+        setNeedsGSSecurityCookie();
+        const unsigned dummy   = lvaGrabTempWithImplicitUse(false DEBUGARG("GSCookie dummy for inlinee"));
+        lvaTable[dummy].lvType = TYP_INT;
+    }
+
     // If there is non-NULL return, replace the GT_CALL with its return value expression,
     // so later it will be picked up by the GT_RET_EXPR node.
     if ((pInlineInfo->inlineCandidateInfo->fncRetType != TYP_VOID) || (iciCall->gtReturnType == TYP_STRUCT))

src/tests/JIT/Regression/JitBlue/Runtime_51612/Runtime_51612.cs

@@ -0,0 +1,81 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+using System;
+using System.Runtime.CompilerServices;
+
+namespace Runtime_51612
+{
+    class Program
+    {
+        struct PassedViaReturnBuffer
+        {
+            public int _0;
+            public int _1;
+        }
+
+        abstract class Base
+        {
+            public unsafe abstract PassedViaReturnBuffer HasEspBasedFrame();
+        }
+
+        class Derived : Base
+        {
+            public Derived(Exception ex)
+            {
+                _ex = ex;
+            }
+
+            readonly Exception _ex;
+
+            public override PassedViaReturnBuffer HasEspBasedFrame()
+            {
+                DoesNotReturn();
+                PassedViaReturnBuffer retBuf;
+                retBuf = RequiresGuardStack();
+                return retBuf;
+            }
+
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            static unsafe PassedViaReturnBuffer RequiresGuardStack()
+            {
+                int* p = stackalloc int[2];
+
+                p[0] = 1;
+                p[1] = 2;
+
+                PassedViaReturnBuffer retBuf;
+
+                retBuf._0 = p[0];
+                retBuf._1 = p[1];
+
+                return retBuf;
+            }
+
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            void DoesNotReturn()
+            {
+                throw _ex;
+            }
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        static void AssertsThatGuardStackCookieOffsetIsInvalid(Base x)
+        {
+            x.HasEspBasedFrame();
+        }
+
+        static int Main(string[] args)
+        {
+            try
+            {
+                AssertsThatGuardStackCookieOffsetIsInvalid(new Derived(new Exception()));
+            }
+            catch (Exception ex)
+            {
+                return 100;
+            }
+
+            return 0;
+        }
+    }
+}

src/tests/JIT/Regression/JitBlue/Runtime_51612/Runtime_51612.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+  </PropertyGroup>
+  <PropertyGroup>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <DebugType>None</DebugType>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+</Project>