crossplatform LazyMachState fixes

Author: Max Charlamb

src/coreclr/debug/runtimeinfo/datadescriptor.h

@@ -602,16 +602,14 @@ DEFINE_FRAME_TYPE(HelperMethodFrame_3OBJ)
 DEFINE_FRAME_TYPE(HelperMethodFrame_PROTECTOBJ)
 #undef DEFINE_FRAME_TYPE
 
+#ifdef TARGET_AMD64
 CDAC_TYPE_BEGIN(LazyMachState)
 CDAC_TYPE_SIZE(sizeof(LazyMachState))
 CDAC_TYPE_FIELD(LazyMachState, /*pointer*/, InstructionPointer, cdac_data<LazyMachState>::InstructionPointer)
 CDAC_TYPE_FIELD(LazyMachState, /*pointer*/, StackPointer, cdac_data<LazyMachState>::StackPointer)
 CDAC_TYPE_FIELD(LazyMachState, /*pointer*/, ReturnAddress, cdac_data<LazyMachState>::ReturnAddress)
-CDAC_TYPE_FIELD(LazyMachState, /*pointer*/, CapturedInstructionPointer, offsetof(LazyMachState, m_CaptureRip))
-CDAC_TYPE_FIELD(LazyMachState, /*pointer*/, CapturedStackPointer, offsetof(LazyMachState, m_CaptureRsp))
-CDAC_TYPE_FIELD(LazyMachState, /*CalleeSavedRegisters*/, CalleeSavedRegisters, cdac_data<LazyMachState>::CalleeSavedRegisters)
-CDAC_TYPE_FIELD(LazyMachState, /*CalleeSavedRegistersPointers*/, CalleeSavedRegistersPointers, cdac_data<LazyMachState>::CalleeSavedRegistersPointers)
 CDAC_TYPE_END(LazyMachState)
+#endif // TARGET_AMD64
 
 CDAC_TYPES_END()
 

src/coreclr/vm/amd64/gmscpu.h

@@ -125,8 +125,6 @@ struct cdac_data<LazyMachState>
     static constexpr size_t InstructionPointer = offsetof(LazyMachState, m_Rip);
     static constexpr size_t StackPointer = offsetof(LazyMachState, m_Rsp);
     static constexpr size_t ReturnAddress = offsetof(LazyMachState, _pRetAddr);
-    static constexpr size_t CalleeSavedRegisters = offsetof(LazyMachState, m_Capture);
-    static constexpr size_t CalleeSavedRegistersPointers = offsetof(LazyMachState, m_Ptrs);
 };
 
 inline void LazyMachState::setLazyStateFromUnwind(MachState* copy)

src/native/managed/cdacreader/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/StackWalk/FrameIterator.cs

@@ -39,6 +39,12 @@ public static bool TryGetContext(Target target, Data.Frame frame, [NotNullWhen(t
             case DataType.HelperMethodFrame_3OBJ:
             case DataType.HelperMethodFrame_PROTECTOBJ:
                 Data.HelperMethodFrame helperMethodFrame = target.ProcessedData.GetOrAdd<Data.HelperMethodFrame>(frame.Address);
+                if (helperMethodFrame.LazyMachState.StackPointer is null || helperMethodFrame.LazyMachState.InstructionPointer is null)
+                {
+                    IP = null;
+                    SP = null;
+                    return false;
+                }
                 IP = helperMethodFrame.LazyMachState.InstructionPointer;
                 SP = helperMethodFrame.LazyMachState.StackPointer;
                 return true;

src/native/managed/cdacreader/Microsoft.Diagnostics.DataContractReader.Contracts/Data/Frames/LazyMachState.cs

@@ -14,12 +14,21 @@ static LazyMachState IData<LazyMachState>.Create(Target target, TargetPointer ad
     public LazyMachState(Target target, TargetPointer address)
     {
         Target.TypeInfo type = target.GetTypeInfo(DataType.LazyMachState);
-        InstructionPointer = target.ReadPointer(address + (ulong)type.Fields[nameof(InstructionPointer)].Offset);
-        StackPointer = target.ReadPointer(address + (ulong)type.Fields[nameof(StackPointer)].Offset);
-        ReturnAddress = target.ReadPointer(address + (ulong)type.Fields[nameof(ReturnAddress)].Offset);
+        if (type.Fields.ContainsKey(nameof(InstructionPointer)))
+        {
+            InstructionPointer = target.ReadPointer(address + (ulong)type.Fields[nameof(InstructionPointer)].Offset);
+        }
+        if (type.Fields.ContainsKey(nameof(StackPointer)))
+        {
+            StackPointer = target.ReadPointer(address + (ulong)type.Fields[nameof(StackPointer)].Offset);
+        }
+        if (type.Fields.ContainsKey(nameof(ReturnAddress)))
+        {
+            ReturnAddress = target.ReadPointer(address + (ulong)type.Fields[nameof(ReturnAddress)].Offset);
+        }
     }
 
-    public TargetPointer InstructionPointer { get; }
-    public TargetPointer StackPointer { get; }
-    public TargetPointer ReturnAddress { get; }
+    public TargetPointer? InstructionPointer { get; }
+    public TargetPointer? StackPointer { get; }
+    public TargetPointer? ReturnAddress { get; }
 }