cranelift: Implement pinned reg in interpreter

cranelift/filetests/filetests/runtests/pinned-reg.clif

@@ -0,0 +1,13 @@
+test interpret
+set enable_pinned_reg
+target x86_64
+
+function %read_write(i64) -> i64 {
+block0(v0: i64):
+    set_pinned_reg v0
+    v1 = get_pinned_reg.i64
+    return v1
+}
+; run: %read_write(0) == 0
+; run: %read_write(-1) == -1
+; run: %read_write(0xDEADBEEF_C0FFEEEE) == 0xDEADBEEF_C0FFEEEE

cranelift/interpreter/src/interpreter.rs

@@ -201,6 +201,7 @@ pub struct InterpreterState<'a> {
     pub heaps: Vec<HeapBacking>,
     pub iflags: HashSet<IntCC>,
     pub fflags: HashSet<FloatCC>,
+    pub pinned_reg: DataValue,
 }
 
 impl Default for InterpreterState<'_> {
@@ -213,6 +214,7 @@ impl Default for InterpreterState<'_> {
             heaps: Vec::new(),
             iflags: HashSet::new(),
             fflags: HashSet::new(),
+            pinned_reg: DataValue::U64(0),
         }
     }
 }
@@ -592,10 +594,18 @@ impl<'a> State<'a, DataValue> for InterpreterState<'a> {
                 }
             }
             _ => unimplemented!(),
-        }
+        };
 
         Ok(())
     }
+
+    fn get_pinned_reg(&self) -> DataValue {
+        self.pinned_reg.clone()
+    }
+
+    fn set_pinned_reg(&mut self, v: DataValue) {
+        self.pinned_reg = v;
+    }
 }
 
 #[cfg(test)]

cranelift/interpreter/src/state.rs

@@ -86,6 +86,11 @@ pub trait State<'a, V> {
 
     /// Checks if an address is valid and within a known region of memory
     fn validate_address(&self, address: &Address) -> Result<(), MemoryError>;
+
+    /// Retrieves the current pinned reg value
+    fn get_pinned_reg(&self) -> V;
+    /// Sets a value for the pinned reg
+    fn set_pinned_reg(&mut self, v: V);
 }
 
 #[derive(Error, Debug)]
@@ -187,4 +192,12 @@ where
     fn validate_address(&self, _addr: &Address) -> Result<(), MemoryError> {
         unimplemented!()
     }
+
+    fn get_pinned_reg(&self) -> V {
+        unimplemented!()
+    }
+
+    fn set_pinned_reg(&mut self, _v: V) {
+        unimplemented!()
+    }
 }

cranelift/interpreter/src/step.rs

@@ -407,8 +407,11 @@ where
                 unreachable!()
             }
         }
-        Opcode::GetPinnedReg => unimplemented!("GetPinnedReg"),
-        Opcode::SetPinnedReg => unimplemented!("SetPinnedReg"),
+        Opcode::GetPinnedReg => assign(state.get_pinned_reg()),
+        Opcode::SetPinnedReg => {
+            state.set_pinned_reg(arg(0)?);
+            ControlFlow::Continue
+        }
         Opcode::TableAddr => {
             if let InstructionData::TableAddr { table, offset, .. } = inst {
                 let table = &state.get_current_function().tables[table];