Add methods for checking for full ranges to `Scalar` and `WrappingRange`

Move *_max methods back to util

change to inline instead of inline(always)

Remove valid_range_exclusive from scalar
Use WrappingRange instead

implement always_valid_for in a safer way

Fix accidental edit

7 files changed, 41 insertions, 56 deletions

diff --git a/compiler/rustc_codegen_llvm/src/abi.rs b/compiler/rustc_codegen_llvm/src/abi.rs
index cd55a61cbaf..cf21c2bb6e1 100644
--- a/compiler/rustc_codegen_llvm/src/abi.rs
+++ b/compiler/rustc_codegen_llvm/src/abi.rs
@@ -541,11 +541,8 @@ impl<'tcx> FnAbiLlvmExt<'tcx> for FnAbi<'tcx, Ty<'tcx>> {
             // become 0..0 when the type becomes i1, which would be rejected
             // by the LLVM verifier.
             if let Int(..) = scalar.value {
-                if !scalar.is_bool() {
-                    let range = scalar.valid_range_exclusive(bx);
-                    if range.start != range.end {
-                        bx.range_metadata(callsite, range);
-                    }
+                if !scalar.is_bool() && !scalar.is_always_valid_for(bx) {
+                    bx.range_metadata(callsite, &scalar.valid_range);
                 }
             }
         }
diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs
index da24fe08f0d..8e7be6bcca1 100644
--- a/compiler/rustc_codegen_llvm/src/builder.rs
+++ b/compiler/rustc_codegen_llvm/src/builder.rs
@@ -18,12 +18,12 @@ use rustc_hir::def_id::DefId;
 use rustc_middle::ty::layout::{LayoutError, LayoutOfHelpers, TyAndLayout};
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::Span;
-use rustc_target::abi::{self, Align, Size};
+use rustc_target::abi::{self, Align, Size, WrappingRange};
 use rustc_target::spec::{HasTargetSpec, Target};
 use std::borrow::Cow;
 use std::ffi::CStr;
 use std::iter;
-use std::ops::{Deref, Range};
+use std::ops::Deref;
 use std::ptr;
 use tracing::debug;
 
@@ -464,9 +464,8 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         ) {
             match scalar.value {
                 abi::Int(..) => {
-                    let range = scalar.valid_range_exclusive(bx);
-                    if range.start != range.end {
-                        bx.range_metadata(load, range);
+                    if !scalar.is_always_valid_for(bx) {
+                        bx.range_metadata(load, &scalar.valid_range);
                     }
                 }
                 abi::Pointer if !scalar.valid_range.contains_zero() => {
@@ -555,7 +554,7 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         next_bx
     }
 
-    fn range_metadata(&mut self, load: &'ll Value, range: Range<u128>) {
+    fn range_metadata(&mut self, load: &'ll Value, range: &WrappingRange) {
         if self.sess().target.arch == "amdgpu" {
             // amdgpu/LLVM does something weird and thinks an i64 value is
             // split into a v2i32, halving the bitwidth LLVM expects,
@@ -568,7 +567,7 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
             let llty = self.cx.val_ty(load);
             let v = [
                 self.cx.const_uint_big(llty, range.start),
-                self.cx.const_uint_big(llty, range.end),
+                self.cx.const_uint_big(llty, range.end.wrapping_add(1)),
             ];
 
             llvm::LLVMSetMetadata(
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index 2ca7e8fd7e8..93dc9850fc7 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -20,7 +20,7 @@ use rustc_middle::ty::{self, Instance, Ty, TypeFoldable};
 use rustc_span::source_map::Span;
 use rustc_span::{sym, Symbol};
 use rustc_target::abi::call::{ArgAbi, FnAbi, PassMode};
-use rustc_target::abi::{self, HasDataLayout};
+use rustc_target::abi::{self, HasDataLayout, WrappingRange};
 use rustc_target::spec::abi::Abi;
 
 /// Used by `FunctionCx::codegen_terminator` for emitting common patterns
@@ -1104,7 +1104,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 llval = bx.load(bx.backend_type(arg.layout), llval, align);
                 if let abi::Abi::Scalar(ref scalar) = arg.layout.abi {
                     if scalar.is_bool() {
-                        bx.range_metadata(llval, 0..2);
+                        bx.range_metadata(llval, &WrappingRange { start: 0, end: 1 });
                     }
                 }
                 // We store bools as `i8` so we need to truncate to `i1`.
diff --git a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
index 3d8ea29160b..7bc44729c26 100644
--- a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
@@ -308,8 +308,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                                 // then `i1 1` (i.e., E::B) is effectively `i8 -1`.
                                 signed = !scalar.is_bool() && s;
 
-                                let er = scalar.valid_range_exclusive(bx.cx());
-                                if er.end != er.start
+                                if !scalar.is_always_valid_for(bx.cx())
                                     && scalar.valid_range.end >= scalar.valid_range.start
                                 {
                                     // We want `table[e as usize ± k]` to not
diff --git a/compiler/rustc_codegen_ssa/src/traits/builder.rs b/compiler/rustc_codegen_ssa/src/traits/builder.rs
index afb8ee3c40d..935f2240143 100644
--- a/compiler/rustc_codegen_ssa/src/traits/builder.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/builder.rs
@@ -16,11 +16,9 @@ use crate::MemFlags;
 use rustc_middle::ty::layout::{HasParamEnv, TyAndLayout};
 use rustc_middle::ty::Ty;
 use rustc_span::Span;
-use rustc_target::abi::{Abi, Align, Scalar, Size};
+use rustc_target::abi::{Abi, Align, Scalar, Size, WrappingRange};
 use rustc_target::spec::HasTargetSpec;
 
-use std::ops::Range;
-
 #[derive(Copy, Clone)]
 pub enum OverflowOp {
     Add,
@@ -158,7 +156,7 @@ pub trait BuilderMethods<'a, 'tcx>:
         dest: PlaceRef<'tcx, Self::Value>,
     ) -> Self;
 
-    fn range_metadata(&mut self, load: Self::Value, range: Range<u128>);
+    fn range_metadata(&mut self, load: Self::Value, range: &WrappingRange);
     fn nonnull_metadata(&mut self, load: Self::Value);
 
     fn store(&mut self, val: Self::Value, ptr: Self::Value, align: Align) -> Self::Value;
diff --git a/compiler/rustc_const_eval/src/interpret/validity.rs b/compiler/rustc_const_eval/src/interpret/validity.rs
index 03e0a8e7901..7ae3f98d834 100644
--- a/compiler/rustc_const_eval/src/interpret/validity.rs
+++ b/compiler/rustc_const_eval/src/interpret/validity.rs
@@ -620,38 +620,36 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
         op: &OpTy<'tcx, M::PointerTag>,
         scalar_layout: &ScalarAbi,
     ) -> InterpResult<'tcx> {
-        let value = self.read_scalar(op)?;
-        let valid_range = scalar_layout.valid_range.clone();
-        let WrappingRange { start: lo, end: hi } = valid_range;
-        // Determine the allowed range
-        // `max_hi` is as big as the size fits
-        let max_hi = u128::MAX >> (128 - op.layout.size.bits());
-        assert!(hi <= max_hi);
-        // We could also write `(hi + 1) % (max_hi + 1) == lo` but `max_hi + 1` overflows for `u128`
-        if (lo == 0 && hi == max_hi) || (hi + 1 == lo) {
+        if scalar_layout.valid_range.is_full_for(op.layout.size) {
             // Nothing to check
             return Ok(());
         }
-        // At least one value is excluded. Get the bits.
+        // At least one value is excluded.
+        let valid_range = scalar_layout.valid_range.clone();
+        let WrappingRange { start, end } = valid_range;
+        let max_value = u128::MAX >> (128 - op.layout.size.bits());
+        assert!(end <= max_value);
+        // Determine the allowed range
+        let value = self.read_scalar(op)?;
         let value = try_validation!(
             value.check_init(),
             self.path,
             err_ub!(InvalidUninitBytes(None)) => { "{}", value }
-                expected { "something {}", wrapping_range_format(valid_range, max_hi) },
+                expected { "something {}", wrapping_range_format(valid_range, max_value) },
         );
         let bits = match value.try_to_int() {
             Err(_) => {
                 // So this is a pointer then, and casting to an int failed.
                 // Can only happen during CTFE.
                 let ptr = self.ecx.scalar_to_ptr(value);
-                if lo == 1 && hi == max_hi {
+                if start == 1 && end == max_value {
                     // Only null is the niche.  So make sure the ptr is NOT null.
                     if self.ecx.memory.ptr_may_be_null(ptr) {
                         throw_validation_failure!(self.path,
                             { "a potentially null pointer" }
                             expected {
                                 "something that cannot possibly fail to be {}",
-                                wrapping_range_format(valid_range, max_hi)
+                                wrapping_range_format(valid_range, max_value)
                             }
                         )
                     }
@@ -663,7 +661,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
                         { "a pointer" }
                         expected {
                             "something that cannot possibly fail to be {}",
-                            wrapping_range_format(valid_range, max_hi)
+                            wrapping_range_format(valid_range, max_value)
                         }
                     )
                 }
@@ -676,7 +674,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
         } else {
             throw_validation_failure!(self.path,
                 { "{}", bits }
-                expected { "something {}", wrapping_range_format(valid_range, max_hi) }
+                expected { "something {}", wrapping_range_format(valid_range, max_value) }
             )
         }
     }
diff --git a/compiler/rustc_target/src/abi/mod.rs b/compiler/rustc_target/src/abi/mod.rs
index b0ecd117dd2..4ed8149dadc 100644
--- a/compiler/rustc_target/src/abi/mod.rs
+++ b/compiler/rustc_target/src/abi/mod.rs
@@ -7,7 +7,7 @@ use std::convert::{TryFrom, TryInto};
 use std::fmt;
 use std::iter::Step;
 use std::num::NonZeroUsize;
-use std::ops::{Add, AddAssign, Deref, Mul, Range, RangeInclusive, Sub};
+use std::ops::{Add, AddAssign, Deref, Mul, RangeInclusive, Sub};
 use std::str::FromStr;
 
 use rustc_index::vec::{Idx, IndexVec};
@@ -779,6 +779,14 @@ impl WrappingRange {
         self.end = end;
         self
     }
+
+    /// Returns `true` if `size` completely fills the range.
+    #[inline]
+    pub fn is_full_for(&self, size: Size) -> bool {
+        let max_value = u128::MAX >> (128 - size.bits());
+        debug_assert!(self.start <= max_value && self.end <= max_value);
+        (self.start == 0 && self.end == max_value) || (self.end + 1 == self.start)
+    }
 }
 
 impl fmt::Debug for WrappingRange {
@@ -807,21 +815,10 @@ impl Scalar {
             && matches!(self.valid_range, WrappingRange { start: 0, end: 1 })
     }
 
-    /// Returns the valid range as a `x..y` range.
-    ///
-    /// If `x` and `y` are equal, the range is full, not empty.
-    pub fn valid_range_exclusive<C: HasDataLayout>(&self, cx: &C) -> Range<u128> {
-        // For a (max) value of -1, max will be `-1 as usize`, which overflows.
-        // However, that is fine here (it would still represent the full range),
-        // i.e., if the range is everything.
-        let bits = self.value.size(cx).bits();
-        assert!(bits <= 128);
-        let mask = !0u128 >> (128 - bits);
-        let start = self.valid_range.start;
-        let end = self.valid_range.end;
-        assert_eq!(start, start & mask);
-        assert_eq!(end, end & mask);
-        start..(end.wrapping_add(1) & mask)
+    /// Returns `true` if all possible numbers are valid, i.e `valid_range` covers the whole layout
+    #[inline]
+    pub fn is_always_valid_for<C: HasDataLayout>(&self, cx: &C) -> bool {
+        self.valid_range.is_full_for(self.value.size(cx))
     }
 }
 
@@ -1269,11 +1266,8 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
                 // The range must contain 0.
                 s.valid_range.contains_zero()
             } else {
-                // The range must include all values. `valid_range_exclusive` handles
-                // the wrap-around using target arithmetic; with wrap-around then the full
-                // range is one where `start == end`.
-                let range = s.valid_range_exclusive(cx);
-                range.start == range.end
+                // The range must include all values.
+                s.is_always_valid_for(cx)
             }
         };