Track addresses of arguments (#53)

WoofWare.PawPrint.Domain/IlOp.fs

@@ -389,8 +389,10 @@ type UnaryConstIlOp =
     | Blt_un of int32
     | Ldloc_s of uint8
     | Ldloca_s of uint8
+    /// Load the address of an argument onto the stack.
     | Ldarga of uint16
     | Ldarg_s of uint8
+    /// Load the address of an argument onto the stack.
     | Ldarga_s of uint8
     /// Unconditionally transfer control to this offset from the next instruction;
     /// like Br but can leave a try/filter/catch block too, and ensures surrounding `finally` blocks execute.

WoofWare.PawPrint/BasicCliType.fs

@@ -72,7 +72,9 @@ type CliValueType =
     | Float64 of float
 
 [<RequireQualifiedAccess>]
-type CliRuntimePointerSource = | LocalVariable of sourceThread : ThreadId * methodFrame : int * whichVar : uint16
+type CliRuntimePointerSource =
+    | LocalVariable of sourceThread : ThreadId * methodFrame : int * whichVar : uint16
+    | Argument of sourceThread : ThreadId * methodFrame : int * whichVar : uint16
 
 type CliRuntimePointer =
     | Unmanaged of unit

WoofWare.PawPrint/EvalStack.fs

@@ -4,6 +4,7 @@ open Microsoft.FSharp.Core
 
 type ManagedPointerSource =
     | LocalVariable of sourceThread : ThreadId * methodFrame : int * whichVar : uint16
+    | Argument of sourceThread : ThreadId * methodFrame : int * whichVar : uint16
     | Heap of ManagedHeapAddress
     | Null
 
@@ -11,7 +12,10 @@ type ManagedPointerSource =
         match this with
         | ManagedPointerSource.Null -> "<null pointer>"
         | ManagedPointerSource.Heap addr -> $"%O{addr}"
-        | LocalVariable (source, method, var) -> $"<variable %i{var} in method frame %i{method} of thread %O{source}>"
+        | ManagedPointerSource.LocalVariable (source, method, var) ->
+            $"<variable %i{var} in method frame %i{method} of thread %O{source}>"
+        | ManagedPointerSource.Argument (source, method, var) ->
+            $"<argument %i{var} in method frame %i{method} of thread %O{source}>"
 
 [<RequireQualifiedAccess>]
 type NativeIntSource =
@@ -65,7 +69,9 @@ type EvalStackValue =
         | EvalStackValue.Float f -> $"Float(%f{f})"
         | EvalStackValue.ManagedPointer managedPointerSource -> $"Pointer(%O{managedPointerSource})"
         | EvalStackValue.ObjectRef managedHeapAddress -> $"ObjectRef(%O{managedHeapAddress})"
-        | EvalStackValue.UserDefinedValueType evalStackValues -> failwith "todo"
+        | EvalStackValue.UserDefinedValueType evalStackValues ->
+            let desc = evalStackValues |> List.map string<EvalStackValue> |> String.concat " | "
+            $"Struct(%s{desc})"
 
 [<RequireQualifiedAccess>]
 module EvalStackValue =
@@ -168,6 +174,10 @@ module EvalStackValue =
                     CliRuntimePointerSource.LocalVariable (sourceThread, methodFrame, whichVar)
                     |> CliRuntimePointer.Managed
                     |> CliType.RuntimePointer
+                | ManagedPointerSource.Argument (sourceThread, methodFrame, whichVar) ->
+                    CliRuntimePointerSource.Argument (sourceThread, methodFrame, whichVar)
+                    |> CliRuntimePointer.Managed
+                    |> CliType.RuntimePointer
                 | ManagedPointerSource.Heap managedHeapAddress -> CliType.ObjectRef (Some managedHeapAddress)
                 | ManagedPointerSource.Null -> CliType.ObjectRef None
             | EvalStackValue.NativeInt nativeIntSource ->
@@ -175,7 +185,11 @@ module EvalStackValue =
                 | NativeIntSource.Verbatim 0L -> CliType.ObjectRef None
                 | NativeIntSource.Verbatim i -> failwith $"refusing to interpret verbatim native int {i} as a pointer"
                 | NativeIntSource.FunctionPointer _ -> failwith "TODO"
-            | i -> failwith $"TODO: %O{i}"
+            | EvalStackValue.UserDefinedValueType fields ->
+                match fields with
+                | [ esv ] -> toCliTypeCoerced target esv
+                | fields -> failwith $"TODO: don't know how to coerce struct of {fields} to a pointer"
+            | _ -> failwith $"TODO: {popped}"
         | CliType.Bool _ ->
             match popped with
             | EvalStackValue.Int32 i ->
@@ -194,6 +208,10 @@ module EvalStackValue =
                     CliRuntimePointerSource.LocalVariable (sourceThread, methodFrame, var)
                     |> CliRuntimePointer.Managed
                     |> CliType.RuntimePointer
+                | ManagedPointerSource.Argument (sourceThread, methodFrame, var) ->
+                    CliRuntimePointerSource.Argument (sourceThread, methodFrame, var)
+                    |> CliRuntimePointer.Managed
+                    |> CliType.RuntimePointer
             | _ -> failwith $"TODO: %O{popped}"
         | CliType.Char _ ->
             match popped with
@@ -241,6 +259,9 @@ module EvalStackValue =
                 | CliRuntimePointerSource.LocalVariable (sourceThread, methodFrame, var) ->
                     ManagedPointerSource.LocalVariable (sourceThread, methodFrame, var)
                     |> EvalStackValue.ManagedPointer
+                | CliRuntimePointerSource.Argument (sourceThread, methodFrame, var) ->
+                    ManagedPointerSource.Argument (sourceThread, methodFrame, var)
+                    |> EvalStackValue.ManagedPointer
         | CliType.ValueType fields -> fields |> List.map ofCliType |> EvalStackValue.UserDefinedValueType
 
 type EvalStack =

WoofWare.PawPrint/ExternImplementations/System.Threading.Monitor.fs

@@ -83,6 +83,8 @@ module System_Threading_Monitor =
                     | ManagedPointerSource.LocalVariable (sourceThread, methodFrame, whichVar) ->
                         state
                         |> IlMachineState.setLocalVariable sourceThread methodFrame whichVar (CliType.OfBool true)
+                    | ManagedPointerSource.Argument (sourceThread, methodFrame, whichVar) ->
+                        failwith "not really expecting to *edit* an argument..."
                     | ManagedPointerSource.Heap addr -> failwith "todo: managed heap"
 
                 (state, WhatWeDid.Executed) |> ExecutionResult.Stepped

WoofWare.PawPrint/NullaryIlOp.fs

@@ -80,6 +80,8 @@ module NullaryIlOp =
         | EvalStackValue.ManagedPointer src ->
             match src with
             | ManagedPointerSource.Null -> failwith "TODO: throw NullReferenceException"
+            | ManagedPointerSource.Argument (sourceThread, methodFrame, whichVar) ->
+                failwith "unexpected - can we really write to an argument?"
             | ManagedPointerSource.LocalVariable (sourceThread, methodFrame, whichVar) ->
                 { state with
                     ThreadState =
@@ -668,6 +670,17 @@ module NullaryIlOp =
                 | EvalStackValue.ManagedPointer src ->
                     match src with
                     | ManagedPointerSource.Null -> failwith "unexpected null pointer in Ldind_u1"
+                    | ManagedPointerSource.Argument (sourceThread, methodFrame, whichVar) ->
+                        let methodState =
+                            state.ThreadState.[sourceThread].MethodStates.[methodFrame].Arguments.[int<uint16> whichVar]
+
+                        match methodState with
+                        | CliType.Bool b -> b
+                        | CliType.Numeric numeric -> failwith $"tried to load a Numeric as a u8: {numeric}"
+                        | CliType.Char _ -> failwith "tried to load a Char as a u8"
+                        | CliType.ObjectRef _ -> failwith "tried to load an ObjectRef as a u8"
+                        | CliType.RuntimePointer _ -> failwith "tried to load a RuntimePointer as a u8"
+                        | CliType.ValueType cliTypes -> failwith "todo"
                     | ManagedPointerSource.LocalVariable (sourceThread, methodFrame, whichVar) ->
                         let methodState =
                             state.ThreadState.[sourceThread].MethodStates.[methodFrame].LocalVariables

WoofWare.PawPrint/UnaryConstIlOp.fs

@@ -409,9 +409,27 @@ module internal UnaryConstIlOp =
                 |> IlMachineState.advanceProgramCounter currentThread
 
             state, WhatWeDid.Executed
-        | Ldarga s -> failwith "TODO: Ldarga unimplemented"
+        | Ldarga s ->
+            let executingMethod = state.ThreadState.[currentThread]
+
+            let ptr =
+                ManagedPointerSource.Argument (currentThread, executingMethod.ActiveMethodState, s)
+
+            state
+            |> IlMachineState.pushToEvalStack' (EvalStackValue.ManagedPointer ptr) currentThread
+            |> IlMachineState.advanceProgramCounter currentThread
+            |> Tuple.withRight WhatWeDid.Executed
+        | Ldarga_s b ->
+            let executingMethod = state.ThreadState.[currentThread]
+
+            let ptr =
+                ManagedPointerSource.Argument (currentThread, executingMethod.ActiveMethodState, uint16<byte> b)
+
+            state
+            |> IlMachineState.pushToEvalStack' (EvalStackValue.ManagedPointer ptr) currentThread
+            |> IlMachineState.advanceProgramCounter currentThread
+            |> Tuple.withRight WhatWeDid.Executed
         | Ldarg_s b -> failwith "TODO: Ldarg_s unimplemented"
-        | Ldarga_s b -> failwith "TODO: Ldarga_s unimplemented"
         | Leave i -> leave currentThread i state
         | Leave_s b -> leave currentThread (int<int8> b) state
         | Starg_s b -> failwith "TODO: Starg_s unimplemented"

WoofWare.PawPrint/UnaryMetadataIlOp.fs

@@ -408,6 +408,7 @@ module internal UnaryMetadataIlOp =
                     match source with
                     | ManagedPointerSource.Null -> failwith "TODO: raise NullReferenceException"
                     | ManagedPointerSource.LocalVariable (sourceThread, methodFrame, whichVar) -> failwith "todo"
+                    | ManagedPointerSource.Argument (sourceThread, methodFrame, whichVar) -> failwith "todo"
                     | ManagedPointerSource.Heap addr ->
                         match state.ManagedHeap.NonArrayObjects.TryGetValue addr with
                         | false, _ -> failwith $"todo: array {addr}"
@@ -575,7 +576,12 @@ module internal UnaryMetadataIlOp =
                             state.ThreadState.[sourceThread].MethodStates.[methodFrame].LocalVariables
                                 .[int<uint16> whichVar]
 
-                        failwith $"todo: local variable {currentValue} {field}"
+                        IlMachineState.pushToEvalStack currentValue thread state
+                    | ManagedPointerSource.Argument (sourceThread, methodFrame, whichVar) ->
+                        let currentValue =
+                            state.ThreadState.[sourceThread].MethodStates.[methodFrame].Arguments.[int<uint16> whichVar]
+
+                        IlMachineState.pushToEvalStack currentValue thread state
                     | ManagedPointerSource.Heap managedHeapAddress ->
                         match state.ManagedHeap.NonArrayObjects.TryGetValue managedHeapAddress with
                         | false, _ -> failwith $"todo: array {managedHeapAddress}"