[release/10.0-rc1] JIT: fix issue with EH clause class types for fault/filters from C++/CLI (#118905)

* JIT: fix issue with EH clause class types for fault/filters from C++/CLI

C++/CLI appears to leave the CORINFO_EH_CLAUSE ClassToken/FilterOffset union
set to some nonzero value for fault/filter clauses. The JIT currently just
passes this value along to the runtime.

If a method with such a nonzero field is inlined into a dynamic method, this
trips up a check in the runtime where a nonzero entry for such a field is
interpreted as a class handle, even for fault/filter clauses where it should
be ignored.

Tolerate this by zeroing the field in the JIT.

Note this could not have happened in pre .NET10 as methods
with EH could not be inlined, so a dynamic method would never see such
an EH clause, and in non-dynamic methods this field is ignored for
faults and filters.

Fixes #118837.

* review feedback

* zero eh table on alloc/realloc

---------

Co-authored-by: Andy Ayers <[email protected]>

Author: github-actions[bot]

src/coreclr/jit/fgbasic.cpp

@@ -3741,31 +3741,32 @@ void Compiler::fgFindBasicBlocks()
         }
         else
         {
-            HBtab->ebdTyp = clause.ClassToken;
-
-            /* Set bbCatchTyp as appropriate */
-
+            // Set ebdTyp and bbCatchTyp as appropriate
+            //
             if (clause.Flags & CORINFO_EH_CLAUSE_FINALLY)
             {
                 hndBegBB->bbCatchTyp = BBCT_FINALLY;
+                HBtab->ebdTyp        = 0;
             }
             else
             {
                 if (clause.Flags & CORINFO_EH_CLAUSE_FAULT)
                 {
                     hndBegBB->bbCatchTyp = BBCT_FAULT;
+                    HBtab->ebdTyp        = 0;
                 }
                 else
                 {
-                    hndBegBB->bbCatchTyp = clause.ClassToken;
-
                     // These values should be non-zero value that will
                     // not collide with real tokens for bbCatchTyp
                     if (clause.ClassToken == 0)
                     {
                         BADCODE("Exception catch type is Null");
                     }
 
+                    hndBegBB->bbCatchTyp = clause.ClassToken;
+                    HBtab->ebdTyp        = clause.ClassToken;
+
                     noway_assert(clause.ClassToken != BBCT_FAULT);
                     noway_assert(clause.ClassToken != BBCT_FINALLY);
                     noway_assert(clause.ClassToken != BBCT_FILTER);

src/coreclr/jit/jiteh.cpp

@@ -1522,6 +1522,8 @@ void Compiler::fgAllocEHTable()
 
     compHndBBtab = new (this, CMK_BasicBlock) EHblkDsc[compHndBBtabAllocCount];
 
+    memset(compHndBBtab, 0, compHndBBtabAllocCount * sizeof(*compHndBBtab));
+
     compHndBBtabCount = info.compXcptnsCount;
 }
 
@@ -1883,6 +1885,10 @@ EHblkDsc* Compiler::fgTryAddEHTableEntries(unsigned XTnum, unsigned count, bool
 
         EHblkDsc* newTable = new (this, CMK_BasicBlock) EHblkDsc[compHndBBtabAllocCount];
 
+        // Zero the storage
+
+        memset(newTable, 0, compHndBBtabAllocCount * sizeof(*compHndBBtab));
+
         // Move over the stuff before the new entries
 
         memcpy_s(newTable, compHndBBtabAllocCount * sizeof(*compHndBBtab), compHndBBtab, XTnum * sizeof(*compHndBBtab));

src/coreclr/tools/aot/ILCompiler.ReadyToRun/JitInterface/CorInfoImpl.ReadyToRun.cs

@@ -3117,8 +3117,8 @@ private void setEHcount(uint cEH)
 
         private void setEHinfo(uint EHnumber, ref CORINFO_EH_CLAUSE clause)
         {
-            // Filters don't have class token in the clause.ClassTokenOrOffset
-            if ((clause.Flags & CORINFO_EH_CLAUSE_FLAGS.CORINFO_EH_CLAUSE_FILTER) == 0)
+            // Filters, finallys, and faults don't have class token in the clause.ClassTokenOrOffset
+            if ((clause.Flags & (CORINFO_EH_CLAUSE_FLAGS.CORINFO_EH_CLAUSE_FILTER | CORINFO_EH_CLAUSE_FLAGS.CORINFO_EH_CLAUSE_FINALLY | CORINFO_EH_CLAUSE_FLAGS.CORINFO_EH_CLAUSE_FAULT)) == 0)
             {
                 if (clause.ClassTokenOrOffset != 0)
                 {

src/coreclr/vm/jitinterface.cpp

@@ -12734,7 +12734,7 @@ void CEECodeGenInfo::setEHinfoWorker(
     LOG((LF_EH, LL_INFO1000000, "    FilterOffset  : 0x%08lx  ->  0x%08lx\n",            clause->FilterOffset,  pEHClause->FilterOffset));
 
     if (IsDynamicScope(m_MethodInfo.scope) &&
-        ((pEHClause->Flags & COR_ILEXCEPTION_CLAUSE_FILTER) == 0) &&
+        ((pEHClause->Flags & (COR_ILEXCEPTION_CLAUSE_FILTER | COR_ILEXCEPTION_CLAUSE_FINALLY | COR_ILEXCEPTION_CLAUSE_FAULT)) == 0) &&
         (clause->ClassToken != mdTokenNil))
     {
         ResolvedToken resolved{};