From 5a4d6041ce9c1dc2569265023891b1e1ab0b89d7 Mon Sep 17 00:00:00 2001
From: Jakob Botsch Nielsen <Jakob.botsch.nielsen@gmail.com>
Date: Mon, 19 Apr 2021 20:59:20 +0200
Subject: [PATCH] Fix contract violation when reporting tailcall stub loader
 (#51485)

Fix #51476
---
 src/coreclr/vm/gcenv.ee.cpp |  2 +-
 src/coreclr/vm/method.cpp   | 44 +++++++++++++++++++++++--------------
 src/coreclr/vm/method.hpp   |  1 +
 3 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/src/coreclr/vm/gcenv.ee.cpp b/src/coreclr/vm/gcenv.ee.cpp
index ea327cc73d800..9efb8648a92b9 100644
--- a/src/coreclr/vm/gcenv.ee.cpp
+++ b/src/coreclr/vm/gcenv.ee.cpp
@@ -165,7 +165,7 @@ static void ScanTailCallArgBufferRoots(Thread* pThread, promote_func* fn, ScanCo
         const PortableTailCallFrame* frame = tls->GetFrame();
         if (frame->NextCall != NULL)
         {
-            MethodDesc* pMD = Entry2MethodDesc((PCODE)frame->NextCall, NULL);
+            MethodDesc* pMD = NonVirtualEntry2MethodDesc((PCODE)frame->NextCall);
             if (pMD != NULL)
                 GcReportLoaderAllocator(fn, sc, pMD->GetLoaderAllocator());
         }
diff --git a/src/coreclr/vm/method.cpp b/src/coreclr/vm/method.cpp
index 6b07924ba0f5f..ddbb47779c252 100644
--- a/src/coreclr/vm/method.cpp
+++ b/src/coreclr/vm/method.cpp
@@ -2229,6 +2229,31 @@ PCODE MethodDesc::GetCallTarget(OBJECTREF* pThisObj, TypeHandle ownerType)
     return pTarget;
 }
 
+MethodDesc* NonVirtualEntry2MethodDesc(PCODE entryPoint)
+{
+    CONTRACTL {
+        NOTHROW;
+        GC_NOTRIGGER;
+        MODE_ANY;
+    }
+    CONTRACTL_END
+
+    RangeSection* pRS = ExecutionManager::FindCodeRange(entryPoint, ExecutionManager::GetScanFlags());
+    if (pRS == NULL)
+        return NULL;
+
+    MethodDesc* pMD;
+    if (pRS->pjit->JitCodeToMethodInfo(pRS, entryPoint, &pMD, NULL))
+        return pMD;
+
+    if (pRS->pjit->GetStubCodeBlockKind(pRS, entryPoint) == STUB_CODE_BLOCK_PRECODE)
+        return MethodDesc::GetMethodDescFromStubAddr(entryPoint);
+
+    // We should never get here
+    _ASSERTE(!"NonVirtualEntry2MethodDesc failed for RangeSection");
+    return NULL;
+}
+
 //*******************************************************************************
 // convert an entry point into a method desc
 MethodDesc* Entry2MethodDesc(PCODE entryPoint, MethodTable *pMT)
@@ -2242,27 +2267,14 @@ MethodDesc* Entry2MethodDesc(PCODE entryPoint, MethodTable *pMT)
     }
     CONTRACT_END
 
-    MethodDesc * pMD;
-
-    RangeSection * pRS = ExecutionManager::FindCodeRange(entryPoint, ExecutionManager::GetScanFlags());
-    if (pRS != NULL)
-    {
-        if (pRS->pjit->JitCodeToMethodInfo(pRS, entryPoint, &pMD, NULL))
-            RETURN(pMD);
-
-        if (pRS->pjit->GetStubCodeBlockKind(pRS, entryPoint) == STUB_CODE_BLOCK_PRECODE)
-            RETURN(MethodDesc::GetMethodDescFromStubAddr(entryPoint));
-
-        // We should never get here
-        _ASSERTE(!"Entry2MethodDesc failed for RangeSection");
-        RETURN (NULL);
-    }
+    MethodDesc* pMD = NonVirtualEntry2MethodDesc(entryPoint);
+    if (pMD != NULL)
+        RETURN(pMD);
 
     pMD = VirtualCallStubManagerManager::Entry2MethodDesc(entryPoint, pMT);
     if (pMD != NULL)
         RETURN(pMD);
 
-
     // Is it an FCALL?
     pMD = ECall::MapTargetBackToMethod(entryPoint);
     if (pMD != NULL)
diff --git a/src/coreclr/vm/method.hpp b/src/coreclr/vm/method.hpp
index 5bdea982a7591..60ca2e4b9fb49 100644
--- a/src/coreclr/vm/method.hpp
+++ b/src/coreclr/vm/method.hpp
@@ -2579,6 +2579,7 @@ inline MethodDescChunk *MethodDesc::GetMethodDescChunk() const
                             (sizeof(MethodDescChunk) + (GetMethodDescIndex() * MethodDesc::ALIGNMENT)));
 }
 
+MethodDesc* NonVirtualEntry2MethodDesc(PCODE entryPoint);
 // convert an entry point into a MethodDesc
 MethodDesc* Entry2MethodDesc(PCODE entryPoint, MethodTable *pMT);