Implement passing arguments by ref for win64 ABI

cranelift/codegen/src/ir/extfunc.rs

@@ -156,6 +156,8 @@ pub struct AbiParam {
     /// ABI-specific location of this argument, or `Unassigned` for arguments that have not yet
     /// been legalized.
     pub location: ArgumentLoc,
+    /// Was the argument converted to pointer during legalization?
+    pub legalized_to_pointer: bool,
 }
 
 impl AbiParam {
@@ -166,6 +168,7 @@ impl AbiParam {
             extension: ArgumentExtension::None,
             purpose: ArgumentPurpose::Normal,
             location: Default::default(),
+            legalized_to_pointer: false,
         }
     }
 
@@ -176,6 +179,7 @@ impl AbiParam {
             extension: ArgumentExtension::None,
             purpose,
             location: Default::default(),
+            legalized_to_pointer: false,
         }
     }
 
@@ -186,6 +190,7 @@ impl AbiParam {
             extension: ArgumentExtension::None,
             purpose,
             location: ArgumentLoc::Reg(regunit),
+            legalized_to_pointer: false,
         }
     }
 
@@ -219,6 +224,9 @@ pub struct DisplayAbiParam<'a>(&'a AbiParam, Option<&'a RegInfo>);
 impl<'a> fmt::Display for DisplayAbiParam<'a> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "{}", self.0.value_type)?;
+        if self.0.legalized_to_pointer {
+            write!(f, " ptr")?;
+        }
         match self.0.extension {
             ArgumentExtension::None => {}
             ArgumentExtension::Uext => write!(f, " uext")?,
@@ -415,6 +423,8 @@ mod tests {
         assert_eq!(t.sext().to_string(), "i32 sext");
         t.purpose = ArgumentPurpose::StructReturn;
         assert_eq!(t.to_string(), "i32 uext sret");
+        t.legalized_to_pointer = true;
+        assert_eq!(t.to_string(), "i32 ptr uext sret");
     }
 
     #[test]