Fix stackwalking handling of FP on Wasm in R2R code

src/coreclr/vm/codeman.cpp

@@ -1515,6 +1515,11 @@ void EEJitManager::SetCpuInfo()
     }
 #endif
 
+#if defined(TARGET_WASM)
+    CPUCompileFlags.Set(InstructionSet_WasmBase);
+    CPUCompileFlags.Set(InstructionSet_PackedSimd);
+#endif
+
 #if defined(TARGET_X86) || defined(TARGET_AMD64)
     CPUCompileFlags.Set(InstructionSet_VectorT128);
 

src/coreclr/vm/excep.cpp

@@ -10728,7 +10728,7 @@ void SoftwareExceptionFrame::UpdateContextFromTransitionBlock(TransitionBlock *p
 }
 
 #elif defined(TARGET_WASM)
-
+TADDR GetWasmFramePointerFromStackPointer(TADDR sp);
 void SoftwareExceptionFrame::UpdateContextFromTransitionBlock(TransitionBlock *pTransitionBlock)
 {
     LIMITED_METHOD_CONTRACT;
@@ -10740,7 +10740,7 @@ void SoftwareExceptionFrame::UpdateContextFromTransitionBlock(TransitionBlock *p
     if (pTransitionBlock != nullptr)
     {
         m_Context.InterpreterSP = pTransitionBlock->m_StackPointer;
-        m_Context.InterpreterFP = 0;
+        m_Context.InterpreterFP = GetWasmFramePointerFromStackPointer(m_Context.InterpreterSP);
         m_Context.InterpreterIP = GetWasmVirtualIPFromStackPointer(pTransitionBlock->m_StackPointer);
         m_ReturnAddress = m_Context.InterpreterIP;
         m_Context.InterpreterWalkFramePointer = 0;

src/coreclr/vm/wasm/helpers.cpp

@@ -520,12 +520,26 @@ void FaultingExceptionFrame::UpdateRegDisplay_Impl(const PREGDISPLAY pRD, bool u
     PORTABILITY_ASSERT("FaultingExceptionFrame::UpdateRegDisplay_Impl is not implemented on wasm");
 }
 
+TADDR GetWasmFramePointerFromStackPointer(TADDR sp);
+
 void TransitionFrame::UpdateRegDisplay_Impl(const PREGDISPLAY pRD, bool updateFloats)
 {
     pRD->IsCallerContextValid = FALSE;
 
     pRD->pCurrentContext->InterpreterIP = GetReturnAddress();
-    pRD->pCurrentContext->InterpreterSP = GetSP();
+    TADDR sp = GetSP();
+    pRD->pCurrentContext->InterpreterSP = sp;
+
+    // Recover the frame pointer so GC-info readers can locate frame slots, but only when
+    // the stack pointer refers to a real R2R frame. When this frame represents a transition
+    // out of interpreted code, GetSP() returns the address just past the TransitionBlock (the
+    // outgoing argument area) rather than a frame pointer (see TransitionFrame::GetSP). Decoding
+    // that would dereference arbitrary memory, so leave the frame pointer as 0 in that case.
+    TransitionBlock* pTransitionBlock = (TransitionBlock*)GetTransitionBlock();
+    bool hasR2RStackPointer = (pTransitionBlock != NULL) &&
+                              (pTransitionBlock->m_ReturnAddress != 0) &&
+                              (pTransitionBlock->m_StackPointer != 0);
+    pRD->pCurrentContext->InterpreterFP = hasR2RStackPointer ? GetWasmFramePointerFromStackPointer(sp) : 0;
 
     SyncRegDisplayToCurrentContext(pRD);
 
@@ -1514,13 +1528,15 @@ RtlVirtualUnwind (
         PTR_BYTE pUnwindData = dac_cast<PTR_BYTE>(FunctionEntry->UnwindData + ImageBase);
         ContextRecord->InterpreterSP = fp + DecodeULEB128AsU32(&pUnwindData); // Unwind the frame pointer to the callers stack pointer
         ContextRecord->InterpreterIP = GetWasmVirtualIPFromStackPointer(ContextRecord->InterpreterSP);
+        ContextRecord->InterpreterFP = GetWasmFramePointerFromStackPointer(ContextRecord->InterpreterSP);
     }
     else
     {
         // Unwind failed!
         _ASSERTE(FALSE);
         ContextRecord->InterpreterIP = 0;
         ContextRecord->InterpreterSP = 0;
+        ContextRecord->InterpreterFP = 0;
     }
 
     return nullptr;

src/tests/Common/CLRTest.CrossGen.targets

@@ -130,6 +130,10 @@ if [ ! -z ${RunCrossGen2+x} ]%3B then
         echo --targetos:$(TargetOS) >> "$__ResponseFile"
         echo --verify-type-and-field-layout >> "$__ResponseFile"
         echo --method-layout:random >> "$__ResponseFile"
+        if [ "$(CrossGen2OutputFormat)" == "wasm" ]; then
+            echo --codegenopt:JitWasmNyiToR2RUnsupported=1 >> "$__ResponseFile"
+            echo --codegenopt:JitWasmSimdNyiToR2RUnsupported=1 >> "$__ResponseFile"
+        fi
         if [ ! -z ${CrossGen2SynthesizePgo+x} ]%3B then
             echo --synthesize-random-mibc >> "$__ResponseFile"
             echo --embed-pgo-data >> "$__ResponseFile"
@@ -339,6 +343,10 @@ if defined RunCrossGen2 (
     echo --targetos:$(TargetOS)>>!__ResponseFile!
     echo --verify-type-and-field-layout>>!__ResponseFile!
     echo --method-layout:random>>!__ResponseFile!
+    if "$(CrossGen2OutputFormat)"=="wasm" (
+        echo "--codegenopt:JitWasmNyiToR2RUnsupported=1">>!__ResponseFile!
+        echo "--codegenopt:JitWasmSimdNyiToR2RUnsupported=1">>!__ResponseFile!
+    )
     if not "$(CrossGen2OutputFormat)"=="" (
         echo -f:$(CrossGen2OutputFormat)>>!__ResponseFile!
     )