From 1578955500ab438f80f27361b74a82364caa499f Mon Sep 17 00:00:00 2001 From: Oliver Scherer Date: Tue, 8 Jan 2019 09:25:06 +0100 Subject: [PATCH 1/3] Fix indentation --- src/librustc/ty/context.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs index 4c8f81411163c..a0da7cf2137d0 100644 --- a/src/librustc/ty/context.rs +++ b/src/librustc/ty/context.rs @@ -1767,7 +1767,7 @@ macro_rules! nop_list_lift { impl<'a, 'tcx> Lift<'tcx> for &'a List<$ty> { type Lifted = &'tcx List<$lifted>; fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option { - if self.is_empty() { + if self.is_empty() { return Some(List::empty()); } if tcx.interners.arena.in_arena(*self as *const _) { From 2a1748834e80b2461be4e18d420503d60e687312 Mon Sep 17 00:00:00 2001 From: Oliver Scherer Date: Tue, 8 Jan 2019 12:40:25 +0100 Subject: [PATCH 2/3] Add some size assertions for const eval types --- src/librustc/mir/interpret/pointer.rs | 2 ++ src/librustc/mir/interpret/value.rs | 6 ++++++ src/librustc/ty/sty.rs | 6 ++++++ 3 files changed, 14 insertions(+) diff --git a/src/librustc/mir/interpret/pointer.rs b/src/librustc/mir/interpret/pointer.rs index a046825f088bb..498c0b5b917e9 100644 --- a/src/librustc/mir/interpret/pointer.rs +++ b/src/librustc/mir/interpret/pointer.rs @@ -76,6 +76,8 @@ pub struct Pointer { pub tag: Tag, } +static_assert!(POINTER_SIZE: ::std::mem::size_of::() == 16); + /// Produces a `Pointer` which points to the beginning of the Allocation impl From for Pointer { #[inline(always)] diff --git a/src/librustc/mir/interpret/value.rs b/src/librustc/mir/interpret/value.rs index 76eb43e73d166..896e2ab960cb4 100644 --- a/src/librustc/mir/interpret/value.rs +++ b/src/librustc/mir/interpret/value.rs @@ -32,6 +32,9 @@ pub enum ConstValue<'tcx> { ByRef(AllocId, &'tcx Allocation, Size), } +#[cfg(target_arch = "x86_64")] +static_assert!(CONST_SIZE: ::std::mem::size_of::>() == 56); + impl<'tcx> ConstValue<'tcx> { #[inline] pub fn try_to_scalar(&self) -> Option { @@ -90,6 +93,9 @@ pub enum Scalar { Ptr(Pointer), } +#[cfg(target_arch = "x86_64")] +static_assert!(SCALAR_SIZE: ::std::mem::size_of::() == 24); + impl fmt::Display for Scalar { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { match self { diff --git a/src/librustc/ty/sty.rs b/src/librustc/ty/sty.rs index b98369b62ea37..a42b80e594c64 100644 --- a/src/librustc/ty/sty.rs +++ b/src/librustc/ty/sty.rs @@ -2063,6 +2063,9 @@ pub enum LazyConst<'tcx> { Evaluated(Const<'tcx>), } +#[cfg(target_arch = "x86_64")] +static_assert!(LAZY_CONST_SIZE: ::std::mem::size_of::>() == 72); + impl<'tcx> LazyConst<'tcx> { pub fn map_evaluated(self, f: impl FnOnce(Const<'tcx>) -> Option) -> Option { match self { @@ -2089,6 +2092,9 @@ pub struct Const<'tcx> { pub val: ConstValue<'tcx>, } +#[cfg(target_arch = "x86_64")] +static_assert!(CONST_SIZE: ::std::mem::size_of::>() == 64); + impl<'tcx> Const<'tcx> { #[inline] pub fn from_scalar( From fe50b4eb1d6f7a31c53798bca3d0fa2b0670fa3d Mon Sep 17 00:00:00 2001 From: Oliver Scherer Date: Tue, 8 Jan 2019 13:49:37 +0100 Subject: [PATCH 3/3] `ConstValue::ScalarPair` only needs to represent slices --- src/librustc/ich/impls_ty.rs | 2 +- src/librustc/mir/interpret/value.rs | 24 +++++++---------- src/librustc/mir/mod.rs | 30 ++++++++++------------ src/librustc/ty/structural_impls.rs | 2 +- src/librustc/ty/sty.rs | 4 +-- src/librustc_codegen_ssa/mir/operand.rs | 12 +++------ src/librustc_mir/const_eval.rs | 9 +++---- src/librustc_mir/hair/constant.rs | 4 +-- src/librustc_mir/hair/pattern/_match.rs | 23 +++++++++-------- src/librustc_mir/hair/pattern/mod.rs | 20 ++++++--------- src/librustc_mir/interpret/operand.rs | 4 +-- src/librustc_mir/monomorphize/collector.rs | 7 +---- 12 files changed, 59 insertions(+), 82 deletions(-) diff --git a/src/librustc/ich/impls_ty.rs b/src/librustc/ich/impls_ty.rs index 79c2b89522dbf..bd2349161f74a 100644 --- a/src/librustc/ich/impls_ty.rs +++ b/src/librustc/ich/impls_ty.rs @@ -302,7 +302,7 @@ impl_stable_hash_for!(struct ty::FieldDef { impl_stable_hash_for!( impl<'tcx> for enum mir::interpret::ConstValue<'tcx> [ mir::interpret::ConstValue ] { Scalar(val), - ScalarPair(a, b), + Slice(a, b), ByRef(id, alloc, offset), } ); diff --git a/src/librustc/mir/interpret/value.rs b/src/librustc/mir/interpret/value.rs index 896e2ab960cb4..4ac84bcfd1903 100644 --- a/src/librustc/mir/interpret/value.rs +++ b/src/librustc/mir/interpret/value.rs @@ -22,10 +22,13 @@ pub enum ConstValue<'tcx> { /// Not using the enum `Value` to encode that this must not be `Undef` Scalar(Scalar), - /// Used only for *fat pointers* with layout::abi::ScalarPair + /// Used only for slices and strings (`&[T]`, `&str`, `*const [T]`, `*mut str`, `Box`, ...) /// - /// Needed for pattern matching code related to slices and strings. - ScalarPair(Scalar, Scalar), + /// Empty slices don't necessarily have an address backed by an `AllocId`, thus we also need to + /// enable integer pointers. The `Scalar` type covers exactly those two cases. While we could + /// create dummy-`AllocId`s, the additional code effort for the conversions doesn't seem worth + /// it. + Slice(Scalar, u64), /// An allocation + offset into the allocation. /// Invariant: The AllocId matches the allocation. @@ -33,14 +36,14 @@ pub enum ConstValue<'tcx> { } #[cfg(target_arch = "x86_64")] -static_assert!(CONST_SIZE: ::std::mem::size_of::>() == 56); +static_assert!(CONST_SIZE: ::std::mem::size_of::>() == 40); impl<'tcx> ConstValue<'tcx> { #[inline] pub fn try_to_scalar(&self) -> Option { match *self { ConstValue::ByRef(..) | - ConstValue::ScalarPair(..) => None, + ConstValue::Slice(..) => None, ConstValue::Scalar(val) => Some(val), } } @@ -59,17 +62,8 @@ impl<'tcx> ConstValue<'tcx> { pub fn new_slice( val: Scalar, len: u64, - cx: &impl HasDataLayout ) -> Self { - ConstValue::ScalarPair(val, Scalar::Bits { - bits: len as u128, - size: cx.data_layout().pointer_size.bytes() as u8, - }) - } - - #[inline] - pub fn new_dyn_trait(val: Scalar, vtable: Pointer) -> Self { - ConstValue::ScalarPair(val, Scalar::Ptr(vtable)) + ConstValue::Slice(val, len) } } diff --git a/src/librustc/mir/mod.rs b/src/librustc/mir/mod.rs index f824ab7e5b395..82083b4f69964 100644 --- a/src/librustc/mir/mod.rs +++ b/src/librustc/mir/mod.rs @@ -2702,23 +2702,21 @@ pub fn fmt_const_val(f: &mut impl Write, const_val: ty::Const<'_>) -> fmt::Resul return write!(f, "{}", item_path_str(did)); } // print string literals - if let ConstValue::ScalarPair(ptr, len) = value { + if let ConstValue::Slice(ptr, len) = value { if let Scalar::Ptr(ptr) = ptr { - if let Scalar::Bits { bits: len, .. } = len { - if let Ref(_, &ty::TyS { sty: Str, .. }, _) = ty.sty { - return ty::tls::with(|tcx| { - let alloc = tcx.alloc_map.lock().get(ptr.alloc_id); - if let Some(interpret::AllocKind::Memory(alloc)) = alloc { - assert_eq!(len as usize as u128, len); - let slice = - &alloc.bytes[(ptr.offset.bytes() as usize)..][..(len as usize)]; - let s = ::std::str::from_utf8(slice).expect("non utf8 str from miri"); - write!(f, "{:?}", s) - } else { - write!(f, "pointer to erroneous constant {:?}, {:?}", ptr, len) - } - }); - } + if let Ref(_, &ty::TyS { sty: Str, .. }, _) = ty.sty { + return ty::tls::with(|tcx| { + let alloc = tcx.alloc_map.lock().get(ptr.alloc_id); + if let Some(interpret::AllocKind::Memory(alloc)) = alloc { + assert_eq!(len as usize as u64, len); + let slice = + &alloc.bytes[(ptr.offset.bytes() as usize)..][..(len as usize)]; + let s = ::std::str::from_utf8(slice).expect("non utf8 str from miri"); + write!(f, "{:?}", s) + } else { + write!(f, "pointer to erroneous constant {:?}, {:?}", ptr, len) + } + }); } } } diff --git a/src/librustc/ty/structural_impls.rs b/src/librustc/ty/structural_impls.rs index 258470bf6f860..28f5a65374d98 100644 --- a/src/librustc/ty/structural_impls.rs +++ b/src/librustc/ty/structural_impls.rs @@ -498,7 +498,7 @@ impl<'a, 'tcx> Lift<'tcx> for ConstValue<'a> { fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option { match *self { ConstValue::Scalar(x) => Some(ConstValue::Scalar(x)), - ConstValue::ScalarPair(x, y) => Some(ConstValue::ScalarPair(x, y)), + ConstValue::Slice(x, y) => Some(ConstValue::Slice(x, y)), ConstValue::ByRef(x, alloc, z) => Some(ConstValue::ByRef( x, alloc.lift_to_tcx(tcx)?, z, )), diff --git a/src/librustc/ty/sty.rs b/src/librustc/ty/sty.rs index a42b80e594c64..671a0fc2d5d7a 100644 --- a/src/librustc/ty/sty.rs +++ b/src/librustc/ty/sty.rs @@ -2064,7 +2064,7 @@ pub enum LazyConst<'tcx> { } #[cfg(target_arch = "x86_64")] -static_assert!(LAZY_CONST_SIZE: ::std::mem::size_of::>() == 72); +static_assert!(LAZY_CONST_SIZE: ::std::mem::size_of::>() == 56); impl<'tcx> LazyConst<'tcx> { pub fn map_evaluated(self, f: impl FnOnce(Const<'tcx>) -> Option) -> Option { @@ -2093,7 +2093,7 @@ pub struct Const<'tcx> { } #[cfg(target_arch = "x86_64")] -static_assert!(CONST_SIZE: ::std::mem::size_of::>() == 64); +static_assert!(CONST_SIZE: ::std::mem::size_of::>() == 48); impl<'tcx> Const<'tcx> { #[inline] diff --git a/src/librustc_codegen_ssa/mir/operand.rs b/src/librustc_codegen_ssa/mir/operand.rs index 2026e042ef0eb..8aad4c1f6e1c0 100644 --- a/src/librustc_codegen_ssa/mir/operand.rs +++ b/src/librustc_codegen_ssa/mir/operand.rs @@ -88,9 +88,9 @@ impl<'a, 'tcx: 'a, V: CodegenObject> OperandRef<'tcx, V> { ); OperandValue::Immediate(llval) }, - ConstValue::ScalarPair(a, b) => { - let (a_scalar, b_scalar) = match layout.abi { - layout::Abi::ScalarPair(ref a, ref b) => (a, b), + ConstValue::Slice(a, b) => { + let a_scalar = match layout.abi { + layout::Abi::ScalarPair(ref a, _) => a, _ => bug!("from_const: invalid ScalarPair layout: {:#?}", layout) }; let a_llval = bx.cx().scalar_to_backend( @@ -98,11 +98,7 @@ impl<'a, 'tcx: 'a, V: CodegenObject> OperandRef<'tcx, V> { a_scalar, bx.cx().scalar_pair_element_backend_type(layout, 0, true), ); - let b_llval = bx.cx().scalar_to_backend( - b, - b_scalar, - bx.cx().scalar_pair_element_backend_type(layout, 1, true), - ); + let b_llval = bx.cx().const_usize(b); OperandValue::Pair(a_llval, b_llval) }, ConstValue::ByRef(_, alloc, offset) => { diff --git a/src/librustc_mir/const_eval.rs b/src/librustc_mir/const_eval.rs index 9ed480a9af5bb..f83a930353b73 100644 --- a/src/librustc_mir/const_eval.rs +++ b/src/librustc_mir/const_eval.rs @@ -67,14 +67,11 @@ pub fn op_to_const<'tcx>( op: OpTy<'tcx>, may_normalize: bool, ) -> EvalResult<'tcx, ty::Const<'tcx>> { - // We do not normalize just any data. Only scalar layout and fat pointers. + // We do not normalize just any data. Only scalar layout and slices. let normalize = may_normalize && match op.layout.abi { layout::Abi::Scalar(..) => true, - layout::Abi::ScalarPair(..) => { - // Must be a fat pointer - op.layout.ty.builtin_deref(true).is_some() - }, + layout::Abi::ScalarPair(..) => op.layout.ty.is_slice(), _ => false, }; let normalized_op = if normalize { @@ -103,7 +100,7 @@ pub fn op_to_const<'tcx>( Ok(Immediate::Scalar(x)) => ConstValue::Scalar(x.not_undef()?), Ok(Immediate::ScalarPair(a, b)) => - ConstValue::ScalarPair(a.not_undef()?, b.not_undef()?), + ConstValue::Slice(a.not_undef()?, b.to_usize(ecx)?), }; Ok(ty::Const { val, ty: op.layout.ty }) } diff --git a/src/librustc_mir/hair/constant.rs b/src/librustc_mir/hair/constant.rs index f63c3e2ff6142..21c471d49ee66 100644 --- a/src/librustc_mir/hair/constant.rs +++ b/src/librustc_mir/hair/constant.rs @@ -35,13 +35,13 @@ crate fn lit_to_const<'a, 'gcx, 'tcx>( LitKind::Str(ref s, _) => { let s = s.as_str(); let id = tcx.allocate_bytes(s.as_bytes()); - ConstValue::new_slice(Scalar::Ptr(id.into()), s.len() as u64, &tcx) + ConstValue::new_slice(Scalar::Ptr(id.into()), s.len() as u64) }, LitKind::Err(ref s) => { let s = s.as_str(); let id = tcx.allocate_bytes(s.as_bytes()); return Ok(ty::Const { - val: ConstValue::new_slice(Scalar::Ptr(id.into()), s.len() as u64, &tcx), + val: ConstValue::new_slice(Scalar::Ptr(id.into()), s.len() as u64), ty: tcx.types.err, }); }, diff --git a/src/librustc_mir/hair/pattern/_match.rs b/src/librustc_mir/hair/pattern/_match.rs index 9cc5c93de41d8..7f5b1a761d261 100644 --- a/src/librustc_mir/hair/pattern/_match.rs +++ b/src/librustc_mir/hair/pattern/_match.rs @@ -221,13 +221,16 @@ impl<'a, 'tcx> LiteralExpander<'a, 'tcx> { // unsize array to slice if pattern is array but match value or other patterns are slice (ConstValue::Scalar(Scalar::Ptr(p)), ty::Array(t, n), ty::Slice(u)) => { assert_eq!(t, u); - ConstValue::ScalarPair( + ConstValue::Slice( Scalar::Ptr(p), - n.map_evaluated(|val| val.val.try_to_scalar()).unwrap(), + n.map_evaluated(|val| val.val.try_to_scalar()) + .unwrap() + .to_usize(&self.tcx) + .unwrap(), ) }, // fat pointers stay the same - (ConstValue::ScalarPair(..), _, _) => val, + (ConstValue::Slice(..), _, _) => val, // FIXME(oli-obk): this is reachable for `const FOO: &&&u32 = &&&42;` being used _ => bug!("cannot deref {:#?}, {} -> {}", val, crty, rty), } @@ -788,9 +791,9 @@ fn max_slice_length<'p, 'a: 'p, 'tcx: 'a, I>( max_fixed_len, n.unwrap_usize(cx.tcx), ), - (ConstValue::ScalarPair(_, n), ty::Slice(_)) => max_fixed_len = cmp::max( + (ConstValue::Slice(_, n), ty::Slice(_)) => max_fixed_len = cmp::max( max_fixed_len, - n.to_usize(&cx.tcx).unwrap(), + n, ), _ => {}, } @@ -1432,7 +1435,7 @@ fn slice_pat_covered_by_const<'tcx>( alloc.get_bytes(&tcx, ptr, Size::from_bytes(n)).unwrap() }, // a slice fat pointer to a zero length slice - (ConstValue::ScalarPair(Scalar::Bits { .. }, n), ty::Slice(t)) => { + (ConstValue::Slice(Scalar::Bits { .. }, 0), ty::Slice(t)) => { if *t != tcx.types.u8 { // FIXME(oli-obk): can't mix const patterns with slice patterns and get // any sort of exhaustiveness/unreachable check yet @@ -1440,11 +1443,10 @@ fn slice_pat_covered_by_const<'tcx>( // are definitely unreachable. return Ok(false); } - assert_eq!(n.to_usize(&tcx).unwrap(), 0); &[] }, // - (ConstValue::ScalarPair(Scalar::Ptr(ptr), n), ty::Slice(t)) => { + (ConstValue::Slice(Scalar::Ptr(ptr), n), ty::Slice(t)) => { if *t != tcx.types.u8 { // FIXME(oli-obk): can't mix const patterns with slice patterns and get // any sort of exhaustiveness/unreachable check yet @@ -1452,7 +1454,6 @@ fn slice_pat_covered_by_const<'tcx>( // are definitely unreachable. return Ok(false); } - let n = n.to_usize(&tcx).unwrap(); tcx.alloc_map .lock() .unwrap_memory(ptr.alloc_id) @@ -1784,12 +1785,12 @@ fn specialize<'p, 'a: 'p, 'tcx: 'a>( }, ty::TyKind::Slice(t) => { match value.val { - ConstValue::ScalarPair(ptr, n) => ( + ConstValue::Slice(ptr, n) => ( ptr.to_ptr().ok().map(|ptr| ( ptr, cx.tcx.alloc_map.lock().unwrap_memory(ptr.alloc_id), )), - n.to_bits(cx.tcx.data_layout.pointer_size).unwrap() as u64, + n, t, ), _ => span_bug!( diff --git a/src/librustc_mir/hair/pattern/mod.rs b/src/librustc_mir/hair/pattern/mod.rs index 06a50f35be1cf..7d48cdc1d8aef 100644 --- a/src/librustc_mir/hair/pattern/mod.rs +++ b/src/librustc_mir/hair/pattern/mod.rs @@ -1218,25 +1218,21 @@ pub fn compare_const_vals<'a, 'gcx, 'tcx>( if let ty::Str = ty.value.sty { match (a.val, b.val) { ( - ConstValue::ScalarPair( + ConstValue::Slice( Scalar::Ptr(ptr_a), len_a, ), - ConstValue::ScalarPair( + ConstValue::Slice( Scalar::Ptr(ptr_b), len_b, ), ) if ptr_a.offset.bytes() == 0 && ptr_b.offset.bytes() == 0 => { - if let Ok(len_a) = len_a.to_bits(tcx.data_layout.pointer_size) { - if let Ok(len_b) = len_b.to_bits(tcx.data_layout.pointer_size) { - if len_a == len_b { - let map = tcx.alloc_map.lock(); - let alloc_a = map.unwrap_memory(ptr_a.alloc_id); - let alloc_b = map.unwrap_memory(ptr_b.alloc_id); - if alloc_a.bytes.len() as u128 == len_a { - return from_bool(alloc_a == alloc_b); - } - } + if len_a == len_b { + let map = tcx.alloc_map.lock(); + let alloc_a = map.unwrap_memory(ptr_a.alloc_id); + let alloc_b = map.unwrap_memory(ptr_b.alloc_id); + if alloc_a.bytes.len() as u64 == len_a { + return from_bool(alloc_a == alloc_b); } } } diff --git a/src/librustc_mir/interpret/operand.rs b/src/librustc_mir/interpret/operand.rs index 8741571342f83..e4bee24c88cfa 100644 --- a/src/librustc_mir/interpret/operand.rs +++ b/src/librustc_mir/interpret/operand.rs @@ -555,10 +555,10 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> MemPlace::from_ptr(Pointer::new(id, offset), alloc.align) ).with_default_tag()) }, - ConstValue::ScalarPair(a, b) => + ConstValue::Slice(a, b) => Ok(Operand::Immediate(Immediate::ScalarPair( a.into(), - b.into(), + Scalar::from_uint(b, self.tcx.data_layout.pointer_size).into(), )).with_default_tag()), ConstValue::Scalar(x) => Ok(Operand::Immediate(Immediate::Scalar(x.into())).with_default_tag()), diff --git a/src/librustc_mir/monomorphize/collector.rs b/src/librustc_mir/monomorphize/collector.rs index bc63f8b6ac854..e713ab17c3af5 100644 --- a/src/librustc_mir/monomorphize/collector.rs +++ b/src/librustc_mir/monomorphize/collector.rs @@ -1254,12 +1254,7 @@ fn collect_const<'a, 'tcx>( debug!("visiting const {:?}", constant); match constant.val { - ConstValue::ScalarPair(Scalar::Ptr(a), Scalar::Ptr(b)) => { - collect_miri(tcx, a.alloc_id, output); - collect_miri(tcx, b.alloc_id, output); - } - ConstValue::ScalarPair(_, Scalar::Ptr(ptr)) | - ConstValue::ScalarPair(Scalar::Ptr(ptr), _) | + ConstValue::Slice(Scalar::Ptr(ptr), _) | ConstValue::Scalar(Scalar::Ptr(ptr)) => collect_miri(tcx, ptr.alloc_id, output), ConstValue::ByRef(_id, alloc, _offset) => {