[NativeAOT] Linux/ARM bring-up (3/n) (dotnet#97104)

* Mask thumb bit when setting IP in a context (eg. palContext->SetIp((uintptr_t)&RhpThrowHwEx))

* Set ExInfo.m_pExContext in RhpThrowHwEx

* Remove REGDISPLAY.GetAddrOfIP and it's only usage

* Resolve ARM relocations (also workarounds LLD bug with thumb bit present both in addend and in symbol value)

* Remove REGDISPLAY.pIP/SetAddrOfIP

* Make most of the assembly code PIE compatible

* NativeAOT: Enable DFEATURE_64BIT_ALIGNMENT on linux-arm

* Enable NativeAOT linux-arm build

* Enable DWARF exception handling for linux-arm

* Fix UnwindFuncletInvokeThunk to skip over r2 register saved on stack by RhpCallFilterFunclet

* Fix signature of P/Invoke native code in SafeHandleTest to match the managed one

* Implement missing StackFrameIterator::InternalInit code for ARM

* Fix thumb bit masking in InInterfaceDispatchHelper

* Workaround: Ensure the Thumb bit is set when looking up method info in DWARF. We would fail to lookup methods at their first instruction otherwise.

* Correctly convert the addend for IMAGE_REL_BASED_THUMB_MOV32[_PCREL] into the ELF relocations

* Simplify CMake condition

* Simplify NativeAotSupported conditions

* Fix typo

* Fix IMAGE_REL_BASED_THUMB_MOV32 conversion to ELF

Author: filipnavara

eng/Subsets.props

@@ -112,7 +112,7 @@
 
   <PropertyGroup>
     <!-- CLR NativeAot only builds in a subset of the matrix -->
-    <NativeAotSupported Condition="('$(TargetOS)' == 'windows' or '$(TargetOS)' == 'linux' or '$(TargetOS)' == 'osx' or '$(TargetOS)' == 'maccatalyst' or '$(TargetOS)' == 'iossimulator' or '$(TargetOS)' == 'ios' or '$(TargetOS)' == 'tvossimulator' or '$(TargetOS)' == 'tvos' or '$(TargetOS)' == 'freebsd') and ('$(TargetArchitecture)' == 'x64' or '$(TargetArchitecture)' == 'arm64')">true</NativeAotSupported>
+    <NativeAotSupported Condition="('$(TargetOS)' == 'windows' or '$(TargetOS)' == 'linux' or '$(TargetOS)' == 'osx' or '$(TargetOS)' == 'maccatalyst' or '$(TargetOS)' == 'iossimulator' or '$(TargetOS)' == 'ios' or '$(TargetOS)' == 'tvossimulator' or '$(TargetOS)' == 'tvos' or '$(TargetOS)' == 'freebsd') and ('$(TargetArchitecture)' == 'x64' or '$(TargetArchitecture)' == 'arm64' or '$(TargetArchitecture)' == 'arm')">true</NativeAotSupported>
 
     <!-- If we're building clr.nativeaotlibs and not building the CLR runtime, compile libraries against NativeAOT CoreLib -->
     <UseNativeAotCoreLib Condition="'$(TestNativeAot)' == 'true' or ($(_subset.Contains('+clr.nativeaotlibs+')) and !$(_subset.Contains('+clr.native+')) and !$(_subset.Contains('+clr.runtime+')))">true</UseNativeAotCoreLib>

src/coreclr/CMakeLists.txt

@@ -147,7 +147,7 @@ add_subdirectory(tools/aot/jitinterface)
 
 if(NOT CLR_CROSS_COMPONENTS_BUILD)
   # NativeAOT only buildable for a subset of CoreCLR-supported configurations
-  if(CLR_CMAKE_HOST_ARCH_ARM64 OR CLR_CMAKE_HOST_ARCH_AMD64)
+  if(CLR_CMAKE_HOST_ARCH_ARM64 OR CLR_CMAKE_HOST_ARCH_AMD64 OR CLR_CMAKE_HOST_ARCH_ARM)
     add_subdirectory(nativeaot)
   endif()
 endif(NOT CLR_CROSS_COMPONENTS_BUILD)

src/coreclr/nativeaot/Runtime/CMakeLists.txt

@@ -239,6 +239,9 @@ add_definitions(-DFEATURE_USE_SOFTWARE_WRITE_WATCH_FOR_GC_HEAP)
 if(CLR_CMAKE_TARGET_ARCH_AMD64 OR CLR_CMAKE_TARGET_ARCH_ARM64)
   add_definitions(-DFEATURE_MANUALLY_MANAGED_CARD_BUNDLES)
 endif(CLR_CMAKE_TARGET_ARCH_AMD64 OR CLR_CMAKE_TARGET_ARCH_ARM64)
+if(CLR_CMAKE_TARGET_ARCH_ARM)
+  add_definitions(-DFEATURE_64BIT_ALIGNMENT)
+endif(CLR_CMAKE_TARGET_ARCH_ARM)
 
 add_definitions(-DFEATURE_CUSTOM_IMPORTS)
 add_definitions(-DFEATURE_DYNAMIC_CODE)

src/coreclr/nativeaot/Runtime/EHHelpers.cpp

@@ -27,6 +27,7 @@
 #include "rhbinder.h"
 #include "MethodTable.h"
 #include "MethodTable.inl"
+#include "CommonMacros.inl"
 
 COOP_PINVOKE_HELPER(FC_BOOL_RET, RhpEHEnumInitFromStackFrameIterator, (
     StackFrameIterator* pFrameIter, void ** pMethodStartAddressOut, EHEnum* pEHEnum))
@@ -327,7 +328,7 @@ static bool InWriteBarrierHelper(uintptr_t faultingIP)
         ASSERT(*(uint8_t*)writeBarrierAVLocations[i] != 0xE9); // jmp XXXXXXXX
 #endif
 
-        if (writeBarrierAVLocations[i] == faultingIP)
+        if (PCODEToPINSTR(writeBarrierAVLocations[i]) == faultingIP)
             return true;
     }
 #endif // USE_PORTABLE_HELPERS
@@ -368,7 +369,7 @@ static bool InInterfaceDispatchHelper(uintptr_t faultingIP)
         ASSERT(*(uint8_t*)interfaceDispatchAVLocations[i] != 0xE9); // jmp XXXXXXXX
 #endif
 
-        if (interfaceDispatchAVLocations[i] == faultingIP)
+        if (PCODEToPINSTR(interfaceDispatchAVLocations[i]) == faultingIP)
             return true;
     }
 #endif // USE_PORTABLE_HELPERS
@@ -458,7 +459,7 @@ int32_t __stdcall RhpHardwareExceptionHandler(uintptr_t faultCode, uintptr_t fau
     {
         *arg0Reg = faultCode;
         *arg1Reg = faultingIP;
-        palContext->SetIp((uintptr_t)&RhpThrowHwEx);
+        palContext->SetIp(PCODEToPINSTR((PCODE)&RhpThrowHwEx));
 
         return EXCEPTION_CONTINUE_EXECUTION;
     }
@@ -542,7 +543,7 @@ int32_t __stdcall RhpVectoredExceptionHandler(PEXCEPTION_POINTERS pExPtrs)
 
     if (translateToManagedException)
     {
-        pExPtrs->ContextRecord->SetIp((uintptr_t)&RhpThrowHwEx);
+        pExPtrs->ContextRecord->SetIp(PCODEToPINSTR((PCODE)&RhpThrowHwEx));
         pExPtrs->ContextRecord->SetArg0Reg(faultCode);
         pExPtrs->ContextRecord->SetArg1Reg(faultingIP);
 

src/coreclr/nativeaot/Runtime/StackFrameIterator.cpp

@@ -179,8 +179,7 @@ void StackFrameIterator::InternalInit(Thread * pThreadToWalk, PInvokeTransitionF
 #if !defined(USE_PORTABLE_HELPERS) // @TODO: no portable version of regdisplay
     memset(&m_RegDisplay, 0, sizeof(m_RegDisplay));
     m_RegDisplay.SetIP((PCODE)pFrame->m_RIP);
-    m_RegDisplay.SetAddrOfIP((PTR_PCODE)PTR_HOST_MEMBER(PInvokeTransitionFrame, pFrame, m_RIP));
-    SetControlPC(dac_cast<PTR_VOID>(*(m_RegDisplay.pIP)));
+    SetControlPC(dac_cast<PTR_VOID>(m_RegDisplay.GetIP()));
 
     PTR_UIntNative pPreservedRegsCursor = (PTR_UIntNative)PTR_HOST_MEMBER(PInvokeTransitionFrame, pFrame, m_PreservedRegs);
 
@@ -388,7 +387,6 @@ void StackFrameIterator::InternalInit(Thread * pThreadToWalk, PTR_PAL_LIMITED_CO
     SetControlPC(dac_cast<PTR_VOID>(pCtx->GetIp()));
     m_RegDisplay.SP   = pCtx->GetSp();
     m_RegDisplay.IP   = pCtx->GetIp();
-    m_RegDisplay.pIP  = PTR_TO_MEMBER(PAL_LIMITED_CONTEXT, pCtx, IP);
 
 #ifdef TARGET_ARM
     //
@@ -540,8 +538,6 @@ void StackFrameIterator::InternalInit(Thread * pThreadToWalk, NATIVE_CONTEXT* pC
 
 #ifdef TARGET_ARM64
 
-    m_RegDisplay.pIP  = (PTR_PCODE)PTR_TO_REG(pCtx, Pc);
-
     //
     // preserved regs
     //
@@ -583,8 +579,6 @@ void StackFrameIterator::InternalInit(Thread * pThreadToWalk, NATIVE_CONTEXT* pC
 
 #elif defined(TARGET_X86) || defined(TARGET_AMD64)
 
-    m_RegDisplay.pIP  = (PTR_PCODE)PTR_TO_REG(pCtx, Rip);
-
     //
     // preserved regs
     //
@@ -611,6 +605,19 @@ void StackFrameIterator::InternalInit(Thread * pThreadToWalk, NATIVE_CONTEXT* pC
     m_RegDisplay.pR10 = (PTR_UIntNative)PTR_TO_REG(pCtx, R10);
     m_RegDisplay.pR11 = (PTR_UIntNative)PTR_TO_REG(pCtx, R11);
 #endif // TARGET_AMD64
+#elif defined(TARGET_ARM)
+
+    m_RegDisplay.pR0 = (PTR_UIntNative)PTR_TO_REG(pCtx, R0);
+    m_RegDisplay.pR1 = (PTR_UIntNative)PTR_TO_REG(pCtx, R1);
+    m_RegDisplay.pR4 = (PTR_UIntNative)PTR_TO_REG(pCtx, R4);
+    m_RegDisplay.pR5 = (PTR_UIntNative)PTR_TO_REG(pCtx, R5);
+    m_RegDisplay.pR6 = (PTR_UIntNative)PTR_TO_REG(pCtx, R6);
+    m_RegDisplay.pR7 = (PTR_UIntNative)PTR_TO_REG(pCtx, R7);
+    m_RegDisplay.pR8 = (PTR_UIntNative)PTR_TO_REG(pCtx, R8);
+    m_RegDisplay.pR9 = (PTR_UIntNative)PTR_TO_REG(pCtx, R9);
+    m_RegDisplay.pR10 = (PTR_UIntNative)PTR_TO_REG(pCtx, R10);
+    m_RegDisplay.pR11 = (PTR_UIntNative)PTR_TO_REG(pCtx, R11);
+    m_RegDisplay.pLR = (PTR_UIntNative)PTR_TO_REG(pCtx, Lr);
 #else
     PORTABILITY_ASSERT("StackFrameIterator::InternalInit");
 #endif // TARGET_ARM
@@ -779,10 +786,9 @@ void StackFrameIterator::UnwindFuncletInvokeThunk()
 #ifdef TARGET_X86
     // First, unwind RhpCallFunclet
     SP = (PTR_UIntNative)(m_RegDisplay.SP + 0x4);   // skip the saved assembly-routine-EBP
-    m_RegDisplay.SetAddrOfIP(SP);
     m_RegDisplay.SetIP(*SP++);
     m_RegDisplay.SetSP((uintptr_t)dac_cast<TADDR>(SP));
-    SetControlPC(dac_cast<PTR_VOID>(*(m_RegDisplay.pIP)));
+    SetControlPC(dac_cast<PTR_VOID>(m_RegDisplay.GetIP()));
 
     ASSERT(
         EQUALS_RETURN_ADDRESS(m_ControlPC, RhpCallCatchFunclet2) ||
@@ -908,12 +914,12 @@ void StackFrameIterator::UnwindFuncletInvokeThunk()
 
     SP = (PTR_UIntNative)d;
 
+    // RhpCallCatchFunclet puts a couple of extra things on the stack that aren't put there by the other two
+    // thunks, but we don't need to know what they are here, so we just skip them.
+    SP += EQUALS_RETURN_ADDRESS(m_ControlPC, RhpCallCatchFunclet2) ? 3 : 1;
+
     if (!isFilterInvoke)
     {
-        // RhpCallCatchFunclet puts a couple of extra things on the stack that aren't put there by the other two
-        // thunks, but we don't need to know what they are here, so we just skip them.
-        SP += EQUALS_RETURN_ADDRESS(m_ControlPC, RhpCallCatchFunclet2) ? 3 : 1;
-
         // Save the preserved regs portion of the REGDISPLAY across the unwind through the C# EH dispatch code.
         m_funcletPtrs.pR4  = m_RegDisplay.pR4;
         m_funcletPtrs.pR5  = m_RegDisplay.pR5;
@@ -966,7 +972,6 @@ void StackFrameIterator::UnwindFuncletInvokeThunk()
 
     m_RegDisplay.pFP  = SP++;
 
-    m_RegDisplay.SetAddrOfIP((PTR_PCODE)SP);
     m_RegDisplay.SetIP(*SP++);
 
     m_RegDisplay.pX19 = SP++;
@@ -986,12 +991,11 @@ void StackFrameIterator::UnwindFuncletInvokeThunk()
 #endif
 
 #if !defined(TARGET_ARM64)
-    m_RegDisplay.SetAddrOfIP((PTR_PCODE)SP);
     m_RegDisplay.SetIP(*SP++);
 #endif
 
     m_RegDisplay.SetSP((uintptr_t)dac_cast<TADDR>(SP));
-    SetControlPC(dac_cast<PTR_VOID>(*(m_RegDisplay.pIP)));
+    SetControlPC(dac_cast<PTR_VOID>(m_RegDisplay.GetIP()));
 
     // We expect to be called by the runtime's C# EH implementation, and since this function's notion of how
     // to unwind through the stub is brittle relative to the stub itself, we want to check as soon as we can.
@@ -1170,10 +1174,9 @@ void StackFrameIterator::UnwindUniversalTransitionThunk()
     stackFrame->UnwindNonVolatileRegisters(&m_RegDisplay);
 
     PTR_UIntNative addressOfPushedCallerIP = stackFrame->get_AddressOfPushedCallerIP();
-    m_RegDisplay.SetAddrOfIP((PTR_PCODE)addressOfPushedCallerIP);
     m_RegDisplay.SetIP(*addressOfPushedCallerIP);
     m_RegDisplay.SetSP((uintptr_t)dac_cast<TADDR>(stackFrame->get_CallerSP()));
-    SetControlPC(dac_cast<PTR_VOID>(*(m_RegDisplay.pIP)));
+    SetControlPC(dac_cast<PTR_VOID>(m_RegDisplay.GetIP()));
 
     // All universal transition cases rely on conservative GC reporting being applied to the
     // full argument set that flowed into the call.  Report the lower bound of this range (the
@@ -1262,7 +1265,6 @@ void StackFrameIterator::UnwindThrowSiteThunk()
     ASSERT_UNCONDITIONALLY("NYI for this arch");
 #endif
 
-    m_RegDisplay.SetAddrOfIP(PTR_TO_MEMBER(PAL_LIMITED_CONTEXT, pContext, IP));
     m_RegDisplay.SetIP(pContext->IP);
     m_RegDisplay.SetSP(pContext->GetSp());
     SetControlPC(dac_cast<PTR_VOID>(pContext->IP));
@@ -1355,7 +1357,7 @@ void StackFrameIterator::NextInternal()
         // if the thread is safe to walk, it better not have a hijack in place.
         ASSERT(!m_pThread->IsHijacked());
 
-        SetControlPC(dac_cast<PTR_VOID>(*(m_RegDisplay.GetAddrOfIP())));
+        SetControlPC(dac_cast<PTR_VOID>(m_RegDisplay.GetIP()));
 
         PTR_VOID collapsingTargetFrame = NULL;
 

src/coreclr/nativeaot/Runtime/amd64/AsmOffsetsCpu.h

@@ -71,28 +71,28 @@ PLAT_ASM_OFFSET(90, REGDISPLAY, Xmm)
 
 #else // !UNIX_AMD64_ABI
 
-PLAT_ASM_SIZEOF(1b0, ExInfo)
+PLAT_ASM_SIZEOF(1a8, ExInfo)
 PLAT_ASM_OFFSET(0, ExInfo, m_pPrevExInfo)
 PLAT_ASM_OFFSET(8, ExInfo, m_pExContext)
 PLAT_ASM_OFFSET(10, ExInfo, m_exception)
 PLAT_ASM_OFFSET(18, ExInfo, m_kind)
 PLAT_ASM_OFFSET(19, ExInfo, m_passNumber)
 PLAT_ASM_OFFSET(1c, ExInfo, m_idxCurClause)
 PLAT_ASM_OFFSET(20, ExInfo, m_frameIter)
-PLAT_ASM_OFFSET(1a8, ExInfo, m_notifyDebuggerSP)
+PLAT_ASM_OFFSET(1a0, ExInfo, m_notifyDebuggerSP)
 
 PLAT_ASM_OFFSET(0, PInvokeTransitionFrame, m_RIP)
 PLAT_ASM_OFFSET(8, PInvokeTransitionFrame, m_FramePointer)
 PLAT_ASM_OFFSET(10, PInvokeTransitionFrame, m_pThread)
 PLAT_ASM_OFFSET(18, PInvokeTransitionFrame, m_Flags)
 PLAT_ASM_OFFSET(20, PInvokeTransitionFrame, m_PreservedRegs)
 
-PLAT_ASM_SIZEOF(188, StackFrameIterator)
+PLAT_ASM_SIZEOF(180, StackFrameIterator)
 PLAT_ASM_OFFSET(10, StackFrameIterator, m_FramePointer)
 PLAT_ASM_OFFSET(18, StackFrameIterator, m_ControlPC)
 PLAT_ASM_OFFSET(20, StackFrameIterator, m_RegDisplay)
-PLAT_ASM_OFFSET(178, StackFrameIterator, m_OriginalControlPC)
-PLAT_ASM_OFFSET(180, StackFrameIterator, m_pPreviousTransitionFrame)
+PLAT_ASM_OFFSET(170, StackFrameIterator, m_OriginalControlPC)
+PLAT_ASM_OFFSET(178, StackFrameIterator, m_pPreviousTransitionFrame)
 
 PLAT_ASM_SIZEOF(50, PAL_LIMITED_CONTEXT)
 PLAT_ASM_OFFSET(0, PAL_LIMITED_CONTEXT, IP)
@@ -108,7 +108,7 @@ PLAT_ASM_OFFSET(38, PAL_LIMITED_CONTEXT, R13)
 PLAT_ASM_OFFSET(40, PAL_LIMITED_CONTEXT, R14)
 PLAT_ASM_OFFSET(48, PAL_LIMITED_CONTEXT, R15)
 
-PLAT_ASM_SIZEOF(90, REGDISPLAY)
+PLAT_ASM_SIZEOF(88, REGDISPLAY)
 PLAT_ASM_OFFSET(78, REGDISPLAY, SP)
 
 PLAT_ASM_OFFSET(18, REGDISPLAY, pRbx)

src/coreclr/nativeaot/Runtime/arm/AsmOffsetsCpu.h

@@ -7,28 +7,28 @@
 //
 // NOTE: the offsets MUST be in hex notation WITHOUT the 0x prefix
 
-PLAT_ASM_SIZEOF(140, ExInfo)
+PLAT_ASM_SIZEOF(138, ExInfo)
 PLAT_ASM_OFFSET(0, ExInfo, m_pPrevExInfo)
 PLAT_ASM_OFFSET(4, ExInfo, m_pExContext)
 PLAT_ASM_OFFSET(8, ExInfo, m_exception)
 PLAT_ASM_OFFSET(0c, ExInfo, m_kind)
 PLAT_ASM_OFFSET(0d, ExInfo, m_passNumber)
 PLAT_ASM_OFFSET(10, ExInfo, m_idxCurClause)
 PLAT_ASM_OFFSET(18, ExInfo, m_frameIter)
-PLAT_ASM_OFFSET(138, ExInfo, m_notifyDebuggerSP)
+PLAT_ASM_OFFSET(130, ExInfo, m_notifyDebuggerSP)
 
 PLAT_ASM_OFFSET(4, PInvokeTransitionFrame, m_RIP)
 PLAT_ASM_OFFSET(8, PInvokeTransitionFrame, m_FramePointer)
 PLAT_ASM_OFFSET(0c, PInvokeTransitionFrame, m_pThread)
 PLAT_ASM_OFFSET(10, PInvokeTransitionFrame, m_Flags)
 PLAT_ASM_OFFSET(14, PInvokeTransitionFrame, m_PreservedRegs)
 
-PLAT_ASM_SIZEOF(120, StackFrameIterator)
+PLAT_ASM_SIZEOF(118, StackFrameIterator)
 PLAT_ASM_OFFSET(08, StackFrameIterator, m_FramePointer)
 PLAT_ASM_OFFSET(0c, StackFrameIterator, m_ControlPC)
 PLAT_ASM_OFFSET(10, StackFrameIterator, m_RegDisplay)
-PLAT_ASM_OFFSET(114, StackFrameIterator, m_OriginalControlPC)
-PLAT_ASM_OFFSET(118, StackFrameIterator, m_pPreviousTransitionFrame)
+PLAT_ASM_OFFSET(10c, StackFrameIterator, m_OriginalControlPC)
+PLAT_ASM_OFFSET(110, StackFrameIterator, m_pPreviousTransitionFrame)
 
 PLAT_ASM_SIZEOF(70, PAL_LIMITED_CONTEXT)
 PLAT_ASM_OFFSET(24, PAL_LIMITED_CONTEXT, IP)
@@ -45,7 +45,7 @@ PLAT_ASM_OFFSET(20, PAL_LIMITED_CONTEXT, R11)
 PLAT_ASM_OFFSET(28, PAL_LIMITED_CONTEXT, SP)
 PLAT_ASM_OFFSET(2c, PAL_LIMITED_CONTEXT, LR)
 
-PLAT_ASM_SIZEOF(88, REGDISPLAY)
+PLAT_ASM_SIZEOF(80, REGDISPLAY)
 PLAT_ASM_OFFSET(38, REGDISPLAY, SP)
 
 PLAT_ASM_OFFSET(10, REGDISPLAY, pR4)
@@ -56,4 +56,4 @@ PLAT_ASM_OFFSET(20, REGDISPLAY, pR8)
 PLAT_ASM_OFFSET(24, REGDISPLAY, pR9)
 PLAT_ASM_OFFSET(28, REGDISPLAY, pR10)
 PLAT_ASM_OFFSET(2c, REGDISPLAY, pR11)
-PLAT_ASM_OFFSET(48, REGDISPLAY, D)
+PLAT_ASM_OFFSET(40, REGDISPLAY, D)

src/coreclr/nativeaot/Runtime/arm/ExceptionHandling.S

@@ -62,6 +62,10 @@ NESTED_ENTRY RhpThrowHwEx, _TEXT, NoHandler
         str         r3, [r1, #OFFSETOF__ExInfo__m_pPrevExInfo]      // pExInfo->m_pPrevExInfo = m_pExInfoStackHead
         str         r1, [r0, #OFFSETOF__Thread__m_pExInfoStackHead] // m_pExInfoStackHead = pExInfo
 
+        // set the exception context field on the ExInfo
+        add         r2, sp, #rsp_offsetof_Context                   // r2 <- PAL_LIMITED_CONTEXT*
+        str         r2, [r1, #OFFSETOF__ExInfo__m_pExContext]       // pExInfo->m_pExContext = pContext
+
         mov         r0, r4 	        // restore the exception code
         // r0 contains the exception code
         // r1 contains the address of the ExInfo

src/coreclr/nativeaot/Runtime/arm/GcProbe.S

@@ -1,14 +1,16 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+.syntax unified
+.thumb
+
 #include <unixasmmacros.inc>
 #include "AsmOffsets.inc"
 
 .global RhpGcPoll2
 
 LEAF_ENTRY RhpGcPoll
-    ldr         r0, =RhpTrapThreads
-    ldr         r0, [r0]
+    PREPARE_EXTERNAL_VAR_INDIRECT RhpTrapThreads, r0
     cmp         r0, #TrapThreadsFlags_None
     bne         RhpGcPollRare
     bx          lr

src/coreclr/nativeaot/Runtime/arm/InteropThunksHelpers.S

@@ -42,7 +42,7 @@ NESTED_END RhCommonStub, _TEXT
 // IntPtr RhGetCommonStubAddress()
 //
 LEAF_ENTRY RhGetCommonStubAddress, _TEXT
-          ldr           r0, =C_FUNC(RhCommonStub)
+          PREPARE_EXTERNAL_VAR RhCommonStub, r0
           bx            lr
 LEAF_END RhGetCommonStubAddress, _TEXT