Completely remove very unsafe Sxpinfo object (#540)

Author: DavisVaughan

Cargo.lock

@@ -122,7 +122,7 @@ fn generate_source(
     }
 
     // These don't deparse to a `function` call!
-    if unsafe { IS_S4_OBJECT(old.sexp) != 0 } {
+    if harp::utils::r_is_s4(old.sexp) {
         return Ok(None);
     }
 

crates/ark/src/srcref.rs

@@ -12,7 +12,6 @@ rust-version.workspace = true
 
 [dependencies]
 anyhow = "1.0.80"
-c2rust-bitfields = "0.17.0"
 cfg-if = "1.0.0"
 ctor = "0.1.26"
 harp-macros = { path = "./harp-macros" }

crates/harp/Cargo.toml

@@ -76,7 +76,7 @@ impl Binding {
 
             let value = env.find(name)?;
 
-            if libr::ALTREP(value) != 0 {
+            if r_is_altrep(value) {
                 let value = BindingValue::Altrep {
                     object: RObject::from(value),
                     data1: RObject::from(R_altrep_data1(value)),

crates/harp/src/environment_iter.rs

@@ -22,8 +22,6 @@ use crate::object::r_length;
 use crate::r_symbol;
 use crate::utils::r_assert_type;
 use crate::utils::r_str_to_owned_utf8_unchecked;
-use crate::utils::Sxpinfo;
-use crate::utils::HASHASH_MASK;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct RSymbol {
@@ -39,10 +37,6 @@ impl RSymbol {
         r_assert_type(sexp, &[SYMSXP])?;
         Ok(Self::new_unchecked(sexp))
     }
-
-    pub fn has_hash(&self) -> bool {
-        unsafe { (Sxpinfo::interpret(&PRINTNAME(self.sexp)).gp() & HASHASH_MASK) == 1 }
-    }
 }
 
 impl Ord for RSymbol {

crates/harp/src/symbol.rs

@@ -8,7 +8,6 @@
 use std::ffi::CStr;
 use std::ffi::CString;
 
-use c2rust_bitfields::BitfieldStruct;
 use itertools::Itertools;
 use libr::*;
 use once_cell::sync::Lazy;
@@ -50,55 +49,6 @@ pub fn init_utils() {}
 static RE_SYNTACTIC_IDENTIFIER: Lazy<Regex> =
     Lazy::new(|| Regex::new(r"^[\p{L}\p{Nl}.][\p{L}\p{Nl}\p{Mn}\p{Mc}\p{Nd}\p{Pc}.]*$").unwrap());
 
-#[derive(Copy, Clone, BitfieldStruct)]
-#[repr(C)]
-pub struct Sxpinfo {
-    #[bitfield(name = "rtype", ty = "libc::c_uint", bits = "0..=4")]
-    #[bitfield(name = "scalar", ty = "libc::c_uint", bits = "5..=5")]
-    #[bitfield(name = "obj", ty = "libc::c_uint", bits = "6..=6")]
-    #[bitfield(name = "alt", ty = "libc::c_uint", bits = "7..=7")]
-    #[bitfield(name = "gp", ty = "libc::c_uint", bits = "8..=23")]
-    #[bitfield(name = "mark", ty = "libc::c_uint", bits = "24..=24")]
-    #[bitfield(name = "debug", ty = "libc::c_uint", bits = "25..=25")]
-    #[bitfield(name = "trace", ty = "libc::c_uint", bits = "26..=26")]
-    #[bitfield(name = "spare", ty = "libc::c_uint", bits = "27..=27")]
-    #[bitfield(name = "gcgen", ty = "libc::c_uint", bits = "28..=28")]
-    #[bitfield(name = "gccls", ty = "libc::c_uint", bits = "29..=31")]
-    #[bitfield(name = "named", ty = "libc::c_uint", bits = "32..=47")]
-    #[bitfield(name = "extra", ty = "libc::c_uint", bits = "48..=63")]
-    pub rtype_scalar_obj_alt_gp_mark_debug_trace_spare_gcgen_gccls_named_extra: [u8; 8],
-}
-
-pub static mut ACTIVE_BINDING_MASK: libc::c_uint = 1 << 15;
-pub static mut S4_OBJECT_MASK: libc::c_uint = 1 << 4;
-pub static mut HASHASH_MASK: libc::c_uint = 1;
-
-impl Sxpinfo {
-    pub fn interpret(x: &SEXP) -> &Self {
-        unsafe { (*x as *mut Sxpinfo).as_ref().unwrap() }
-    }
-
-    pub fn is_active(&self) -> bool {
-        self.gp() & unsafe { ACTIVE_BINDING_MASK } != 0
-    }
-
-    pub fn is_immediate(&self) -> bool {
-        self.extra() != 0
-    }
-
-    pub fn is_s4(&self) -> bool {
-        self.gp() & unsafe { S4_OBJECT_MASK } != 0
-    }
-
-    pub fn is_altrep(&self) -> bool {
-        self.alt() != 0
-    }
-
-    pub fn is_object(&self) -> bool {
-        self.obj() != 0
-    }
-}
-
 #[harp::register]
 pub extern "C" fn harp_log_trace(msg: SEXP) -> crate::error::Result<SEXP> {
     let msg = String::try_from(RObject::view(msg))?;
@@ -176,15 +126,15 @@ pub fn r_is_null(object: SEXP) -> bool {
 }
 
 pub fn r_is_altrep(object: SEXP) -> bool {
-    Sxpinfo::interpret(&object).is_altrep()
+    unsafe { libr::ALTREP(object) != 0 }
 }
 
 pub fn r_is_object(object: SEXP) -> bool {
-    Sxpinfo::interpret(&object).is_object()
+    unsafe { libr::OBJECT(object) != 0 }
 }
 
 pub fn r_is_s4(object: SEXP) -> bool {
-    Sxpinfo::interpret(&object).is_s4()
+    unsafe { libr::IS_S4_OBJECT(object) != 0 }
 }
 
 pub fn r_is_unbound(object: SEXP) -> bool {

crates/harp/src/utils.rs

@@ -188,6 +188,8 @@ functions::generate! {
 
     pub fn Rf_xlength(arg1: SEXP) -> R_xlen_t;
 
+    pub fn OBJECT(x: SEXP) -> std::ffi::c_int;
+
     pub fn ALTREP(x: SEXP) -> std::ffi::c_int;
 
     pub fn ALTREP_CLASS(x: SEXP) -> SEXP;