diff --git a/src/librustc_mir/hair/pattern/_match.rs b/src/librustc_mir/hair/pattern/_match.rs index fd869d6c334ab..0570cd278f3af 100644 --- a/src/librustc_mir/hair/pattern/_match.rs +++ b/src/librustc_mir/hair/pattern/_match.rs @@ -309,6 +309,7 @@ pub struct MatchCheckCtxt<'a, 'tcx: 'a> { /// outside it's module and should not be matchable with an empty match /// statement. pub module: DefId, + param_env: ty::ParamEnv<'tcx>, pub pattern_arena: &'a TypedArena>, pub byte_array_map: FxHashMap<*const Pattern<'tcx>, Vec<&'a Pattern<'tcx>>>, } @@ -316,6 +317,7 @@ pub struct MatchCheckCtxt<'a, 'tcx: 'a> { impl<'a, 'tcx> MatchCheckCtxt<'a, 'tcx> { pub fn create_and_enter( tcx: TyCtxt<'a, 'tcx, 'tcx>, + param_env: ty::ParamEnv<'tcx>, module: DefId, f: F) -> R where F: for<'b> FnOnce(MatchCheckCtxt<'b, 'tcx>) -> R @@ -324,53 +326,13 @@ impl<'a, 'tcx> MatchCheckCtxt<'a, 'tcx> { f(MatchCheckCtxt { tcx, + param_env, module, pattern_arena: &pattern_arena, byte_array_map: FxHashMap::default(), }) } - // convert a byte-string pattern to a list of u8 patterns. - fn lower_byte_str_pattern<'p>(&mut self, pat: &'p Pattern<'tcx>) -> Vec<&'p Pattern<'tcx>> - where 'a: 'p - { - let pattern_arena = &*self.pattern_arena; - let tcx = self.tcx; - self.byte_array_map.entry(pat).or_insert_with(|| { - match pat.kind { - box PatternKind::Constant { - value: const_val - } => { - if let Some(ptr) = const_val.to_ptr() { - let is_array_ptr = const_val.ty - .builtin_deref(true) - .and_then(|t| t.ty.builtin_index()) - .map_or(false, |t| t == tcx.types.u8); - assert!(is_array_ptr); - let alloc = tcx.alloc_map.lock().unwrap_memory(ptr.alloc_id); - assert_eq!(ptr.offset.bytes(), 0); - // FIXME: check length - alloc.bytes.iter().map(|b| { - &*pattern_arena.alloc(Pattern { - ty: tcx.types.u8, - span: pat.span, - kind: box PatternKind::Constant { - value: ty::Const::from_bits( - tcx, - *b as u128, - ty::ParamEnv::empty().and(tcx.types.u8)) - } - }) - }).collect() - } else { - bug!("not a byte str: {:?}", const_val) - } - } - _ => span_bug!(pat.span, "unexpected byte array pattern {:?}", pat) - } - }).clone() - } - fn is_uninhabited(&self, ty: Ty<'tcx>) -> bool { if self.tcx.features().exhaustive_patterns { self.tcx.is_ty_uninhabited_from(self.module, ty) @@ -1393,11 +1355,6 @@ fn slice_pat_covered_by_constructor<'tcx>( ConstValue::Scalar(val) | ConstValue::ScalarPair(val, _) => val, }; if let Ok(ptr) = val.to_ptr() { - let is_array_ptr = const_val.ty - .builtin_deref(true) - .and_then(|t| t.ty.builtin_index()) - .map_or(false, |t| t == tcx.types.u8); - assert!(is_array_ptr); tcx.alloc_map.lock().unwrap_memory(ptr.alloc_id).bytes.as_ref() } else { bug!("unexpected non-ptr ConstantValue") @@ -1705,26 +1662,63 @@ fn specialize<'p, 'a: 'p, 'tcx: 'a>( PatternKind::Constant { value } => { match *constructor { Slice(..) => { - if let Some(ptr) = value.to_ptr() { - let is_array_ptr = value.ty - .builtin_deref(true) - .and_then(|t| t.ty.builtin_index()) - .map_or(false, |t| t == cx.tcx.types.u8); - assert!(is_array_ptr); - let data_len = cx.tcx - .alloc_map - .lock() - .unwrap_memory(ptr.alloc_id) - .bytes - .len(); - if wild_patterns.len() == data_len { - Some(cx.lower_byte_str_pattern(pat)) - } else { - None + // we extract an `Option` for the pointer because slices of zero elements don't + // necessarily point to memory, they are usually just integers. The only time + // they should be pointing to memory is when they are subslices of nonzero + // slices + let (opt_ptr, n, ty) = match value.ty.builtin_deref(false).unwrap().ty.sty { + ty::TyKind::Array(t, n) => (value.to_ptr(), n.unwrap_usize(cx.tcx), t), + ty::TyKind::Slice(t) => { + match value.val { + ConstValue::ScalarPair(ptr, n) => ( + ptr.to_ptr().ok(), + n.to_bits(cx.tcx.data_layout.pointer_size).unwrap() as u64, + t, + ), + _ => span_bug!( + pat.span, + "slice pattern constant must be scalar pair but is {:?}", + value, + ), + } + }, + _ => span_bug!( + pat.span, + "unexpected const-val {:?} with ctor {:?}", + value, + constructor, + ), + }; + if wild_patterns.len() as u64 == n { + // convert a constant slice/array pattern to a list of patterns. + match (n, opt_ptr) { + (0, _) => Some(Vec::new()), + (_, Some(ptr)) => { + let alloc = cx.tcx.alloc_map.lock().unwrap_memory(ptr.alloc_id); + let layout = cx.tcx.layout_of(cx.param_env.and(ty)).ok()?; + (0..n).map(|i| { + let ptr = ptr.offset(layout.size * i, &cx.tcx).ok()?; + let scalar = alloc.read_scalar( + &cx.tcx, ptr, layout.size, + ).ok()?; + let scalar = scalar.not_undef().ok()?; + let value = ty::Const::from_scalar(cx.tcx, scalar, ty); + let pattern = Pattern { + ty, + span: pat.span, + kind: box PatternKind::Constant { value }, + }; + Some(&*cx.pattern_arena.alloc(pattern)) + }).collect() + }, + (_, None) => span_bug!( + pat.span, + "non zero length slice with const-val {:?}", + value, + ), } } else { - span_bug!(pat.span, - "unexpected const-val {:?} with ctor {:?}", value, constructor) + None } } _ => { diff --git a/src/librustc_mir/hair/pattern/check_match.rs b/src/librustc_mir/hair/pattern/check_match.rs index bafabe4e9972c..800f644f7f595 100644 --- a/src/librustc_mir/hair/pattern/check_match.rs +++ b/src/librustc_mir/hair/pattern/check_match.rs @@ -193,7 +193,7 @@ impl<'a, 'tcx> MatchVisitor<'a, 'tcx> { } let module = self.tcx.hir.get_module_parent(scrut.id); - MatchCheckCtxt::create_and_enter(self.tcx, module, |ref mut cx| { + MatchCheckCtxt::create_and_enter(self.tcx, self.param_env, module, |ref mut cx| { let mut have_errors = false; let inlined_arms : Vec<(Vec<_>, _)> = arms.iter().map(|arm| ( @@ -268,7 +268,7 @@ impl<'a, 'tcx> MatchVisitor<'a, 'tcx> { fn check_irrefutable(&self, pat: &'tcx Pat, origin: &str) { let module = self.tcx.hir.get_module_parent(pat.id); - MatchCheckCtxt::create_and_enter(self.tcx, module, |ref mut cx| { + MatchCheckCtxt::create_and_enter(self.tcx, self.param_env, module, |ref mut cx| { let mut patcx = PatternContext::new(self.tcx, self.param_env.and(self.identity_substs), self.tables); diff --git a/src/test/ui/pattern/slice-pattern-const-2.rs b/src/test/ui/pattern/slice-pattern-const-2.rs new file mode 100644 index 0000000000000..6f9501d025c26 --- /dev/null +++ b/src/test/ui/pattern/slice-pattern-const-2.rs @@ -0,0 +1,24 @@ +// compile-pass + +fn main() { + let s = &[0x00; 4][..]; //Slice of any value + const MAGIC_TEST: &[u32] = &[4, 5, 6, 7]; //Const slice to pattern match with + match s { + MAGIC_TEST => (), + [0x00, 0x00, 0x00, 0x00] => (), + [4, 5, 6, 7] => (), // this should warn + _ => (), + } + match s { + [0x00, 0x00, 0x00, 0x00] => (), + MAGIC_TEST => (), + [4, 5, 6, 7] => (), // this should warn + _ => (), + } + match s { + [0x00, 0x00, 0x00, 0x00] => (), + [4, 5, 6, 7] => (), + MAGIC_TEST => (), // this should warn + _ => (), + } +} diff --git a/src/test/ui/pattern/slice-pattern-const-3.rs b/src/test/ui/pattern/slice-pattern-const-3.rs new file mode 100644 index 0000000000000..e7a30cef57a8e --- /dev/null +++ b/src/test/ui/pattern/slice-pattern-const-3.rs @@ -0,0 +1,24 @@ +// compile-pass + +fn main() { + let s = &["0x00"; 4][..]; //Slice of any value + const MAGIC_TEST: &[&str] = &["4", "5", "6", "7"]; //Const slice to pattern match with + match s { + MAGIC_TEST => (), + ["0x00", "0x00", "0x00", "0x00"] => (), + ["4", "5", "6", "7"] => (), // this should warn + _ => (), + } + match s { + ["0x00", "0x00", "0x00", "0x00"] => (), + MAGIC_TEST => (), + ["4", "5", "6", "7"] => (), // this should warn + _ => (), + } + match s { + ["0x00", "0x00", "0x00", "0x00"] => (), + ["4", "5", "6", "7"] => (), + MAGIC_TEST => (), // this should warn + _ => (), + } +} diff --git a/src/test/ui/pattern/slice-pattern-const.rs b/src/test/ui/pattern/slice-pattern-const.rs new file mode 100644 index 0000000000000..d353f6cddbd0d --- /dev/null +++ b/src/test/ui/pattern/slice-pattern-const.rs @@ -0,0 +1,24 @@ +//compile-pass + +fn main() { + let s = &[0x00; 4][..]; //Slice of any value + const MAGIC_TEST: &[u8] = b"TEST"; //Const slice to pattern match with + match s { + MAGIC_TEST => (), + [0x00, 0x00, 0x00, 0x00] => (), + [84, 69, 83, 84] => (), // this should warn + _ => (), + } + match s { + [0x00, 0x00, 0x00, 0x00] => (), + MAGIC_TEST => (), + [84, 69, 83, 84] => (), // this should warn + _ => (), + } + match s { + [0x00, 0x00, 0x00, 0x00] => (), + [84, 69, 83, 84] => (), + MAGIC_TEST => (), // this should warn + _ => (), + } +}