[interp] Make InterpreterStub handle being called on threads without a Thread object

src/coreclr/vm/amd64/AsmHelpers.asm

@@ -4,8 +4,6 @@
 include AsmMacros.inc
 include asmconstants.inc
 
-Thread_GetInterpThreadContext  TEXTEQU <?GetInterpThreadContext@Thread@@QEAAPEAUInterpThreadContext@@XZ>
-
 extern PInvokeImportWorker:proc
 extern ThePreStub:proc
 extern  ProfileEnter:proc
@@ -15,7 +13,7 @@ extern OnHijackWorker:proc
 extern JIT_RareDisableHelperWorker:proc
 ifdef FEATURE_INTERPRETER
 extern ExecuteInterpretedMethod:proc
-extern Thread_GetInterpThreadContext:proc
+extern GetInterpThreadContextWithPossiblyMissingThread:proc
 endif
 
 extern g_pPollGC:QWORD
@@ -564,13 +562,16 @@ NESTED_ENTRY InterpreterStub, _TEXT
         mov             rbx, METHODDESC_REGISTER
 
         INLINE_GETTHREAD r10; thrashes rax and r11
+        test            r10, r10
+        jz              NoManagedThread
 
         mov             rax, qword ptr [r10 + OFFSETOF__Thread__m_pInterpThreadContext]
         test            rax, rax
         jnz             HaveInterpThreadContext
 
+NoManagedThread:
         mov             rcx, r10
-        call            Thread_GetInterpThreadContext
+        call            GetInterpThreadContextWithPossiblyMissingThread
         RESTORE_ARGUMENT_REGISTERS __PWTB_ArgumentRegisters
         RESTORE_FLOAT_ARGUMENT_REGISTERS __PWTB_FloatArgumentRegisters
 

src/coreclr/vm/amd64/asmhelpers.S

@@ -443,13 +443,16 @@ NESTED_ENTRY InterpreterStub, _TEXT, NoHandler
 
         INLINE_GETTHREAD // result in rax, it can thrash all argument registers as it can call a helper
         mov             r10, rax
+        test            rax, rax
+        jz              LOCAL_LABEL(NoManagedThread)
 
         mov             rax, qword ptr [r10 + OFFSETOF__Thread__m_pInterpThreadContext]
         test            rax, rax
         jnz             LOCAL_LABEL(HaveInterpThreadContext)
 
+LOCAL_LABEL(NoManagedThread):
         mov             rcx, r10
-        call            C_FUNC(_ZN6Thread22GetInterpThreadContextEv) // Thread::GetInterpThreadContext
+        call            C_FUNC(GetInterpThreadContextWithPossiblyMissingThread)
 
 LOCAL_LABEL(HaveInterpThreadContext):
         mov             r10, qword ptr [rax + OFFSETOF__InterpThreadContext__pStackPointer]
@@ -1708,7 +1711,7 @@ NESTED_ENTRY CallJittedMethodRetVoid, _TEXT, NoHandler
         push_nonvol_reg rbp
         mov  rbp, rsp
         alloc_stack 0x10
-        save_reg_postrsp r10, 0 
+        save_reg_postrsp r10, 0
 END_PROLOGUE
         sub rsp, rcx // total stack space
         mov r11, rdi // The routines list

src/coreclr/vm/arm64/asmhelpers.S

@@ -694,12 +694,14 @@ NESTED_ENTRY InterpreterStub, _TEXT, NoHandler
     mov x21, x0
 #endif
     INLINE_GETTHREAD x20 // thrashes x0 on Apple OSes (and possibly other arg registers on other Unixes)
+    cbz x20, LOCAL_LABEL(NoManagedThread)
 
     ldr x11, [x20, #OFFSETOF__Thread__m_pInterpThreadContext]
     cbnz x11, LOCAL_LABEL(HaveInterpThreadContext)
 
+LOCAL_LABEL(NoManagedThread):
 #ifdef TARGET_APPLE
-    // There Thread::GetInterpThreadContext can destroy all argument registers, so we
+    // GetInterpThreadContextWithPossiblyMissingThread can destroy all argument registers, so we
     // need to save them. For non-Apple, they have been already saved in the PROLOG_WITH_TRANSITION_BLOCK
     // Restore x0 thrashed by the INLINE_GETTHREAD
     mov x0, x21
@@ -708,7 +710,7 @@ NESTED_ENTRY InterpreterStub, _TEXT, NoHandler
 #endif
 
     mov x0, x20
-    bl C_FUNC(_ZN6Thread22GetInterpThreadContextEv) // Thread::GetInterpThreadContext
+    bl C_FUNC(GetInterpThreadContextWithPossiblyMissingThread)
     mov x11, x0
 
 #ifndef TARGET_APPLE

src/coreclr/vm/arm64/asmhelpers.asm

@@ -24,8 +24,7 @@
     IMPORT HijackHandler
     IMPORT ThrowControlForThread
 #ifdef FEATURE_INTERPRETER
-    SETALIAS Thread_GetInterpThreadContext, ?GetInterpThreadContext@Thread@@QEAAPEAUInterpThreadContext@@XZ
-    IMPORT $Thread_GetInterpThreadContext
+    IMPORT GetInterpThreadContextWithPossiblyMissingThread
     IMPORT ExecuteInterpretedMethod
 #endif
 
@@ -1065,12 +1064,14 @@ JIT_PollGCRarePath
         PROLOG_WITH_TRANSITION_BLOCK
 
         INLINE_GETTHREAD x20, x19
+        cbz x20, NoManagedThread
 
         ldr x11, [x20, #OFFSETOF__Thread__m_pInterpThreadContext]
         cbnz x11, HaveInterpThreadContext
 
+NoManagedThread
         mov x0, x20
-        bl $Thread_GetInterpThreadContext
+        bl GetInterpThreadContextWithPossiblyMissingThread
         mov x11, x0
         RESTORE_ARGUMENT_REGISTERS sp, __PWTB_ArgumentRegisters
         RESTORE_FLOAT_ARGUMENT_REGISTERS sp, __PWTB_FloatArgumentRegisters

src/coreclr/vm/threads.cpp

@@ -7702,6 +7702,22 @@ InterpThreadContext* Thread::GetInterpThreadContext()
 
     return m_pInterpThreadContext;
 }
+
+extern "C" InterpThreadContext* STDCALL GetInterpThreadContextWithPossiblyMissingThread(Thread *pThread)
+{
+    CONTRACTL
+    {
+        THROWS;
+    }
+    CONTRACTL_END;
+
+    if (pThread == nullptr)
+    {
+        pThread = SetupThread();
+    }
+
+    return pThread->GetInterpThreadContext();
+}
 #endif // FEATURE_INTERPRETER
 
 /* static */