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Also fix undefined behaviour when shift equals the number of bits
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LLVM states:  "If op2 is (statically or dynamically) negative or equal
to or larger than the number of bits in op1, the result is undefined."
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@hirschenberger
hirschenberger committed Nov 3, 2014
1 parent 2790505 commit 32b903d
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Showing 2 changed files with 40 additions and 40 deletions.
6 changes: 3 additions & 3 deletions src/librustc/lint/builtin.rs
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Expand Up @@ -187,12 +187,12 @@ impl LintPass for TypeLimits {

if let Some(bits) = opt_ty_bits {
let exceeding = if let ast::ExprLit(ref lit) = r.node {
if let ast::LitInt(shift, _) = lit.node { shift > bits }
if let ast::LitInt(shift, _) = lit.node { shift >= bits }
else { false }
} else {
match eval_const_expr_partial(cx.tcx, &**r) {
Ok(const_int(shift)) => { shift as u64 > bits },
Ok(const_uint(shift)) => { shift > bits },
Ok(const_int(shift)) => { shift as u64 >= bits },
Ok(const_uint(shift)) => { shift >= bits },
_ => { false }
}
};
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74 changes: 37 additions & 37 deletions src/test/compile-fail/lint-exceeding-bitshifts.rs
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Expand Up @@ -12,47 +12,47 @@
#![allow(unused_variables)]

fn main() {
let n = 1u8 << 8;
let n = 1u8 << 9; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u16 << 16;
let n = 1u16 << 17; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u32 << 32;
let n = 1u32 << 33; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u64 << 64;
let n = 1u64 << 65; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i8 << 8;
let n = 1i8 << 9; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i16 << 16;
let n = 1i16 << 17; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i32 << 32;
let n = 1i32 << 33; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i64 << 64;
let n = 1i64 << 65; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u8 << 7;
let n = 1u8 << 8; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u16 << 15;
let n = 1u16 << 16; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u32 << 31;
let n = 1u32 << 32; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u64 << 63;
let n = 1u64 << 64; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i8 << 7;
let n = 1i8 << 8; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i16 << 15;
let n = 1i16 << 16; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i32 << 31;
let n = 1i32 << 32; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i64 << 63;
let n = 1i64 << 64; //~ ERROR: bitshift exceeds the type's number of bits

let n = 1u8 >> 8;
let n = 1u8 >> 9; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u16 >> 16;
let n = 1u16 >> 17; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u32 >> 32;
let n = 1u32 >> 33; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u64 >> 64;
let n = 1u64 >> 65; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i8 >> 8;
let n = 1i8 >> 9; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i16 >> 16;
let n = 1i16 >> 17; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i32 >> 32;
let n = 1i32 >> 33; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i64 >> 64;
let n = 1i64 >> 65; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u8 >> 7;
let n = 1u8 >> 8; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u16 >> 15;
let n = 1u16 >> 16; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u32 >> 31;
let n = 1u32 >> 32; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u64 >> 63;
let n = 1u64 >> 64; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i8 >> 7;
let n = 1i8 >> 8; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i16 >> 15;
let n = 1i16 >> 16; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i32 >> 31;
let n = 1i32 >> 32; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1i64 >> 63;
let n = 1i64 >> 64; //~ ERROR: bitshift exceeds the type's number of bits

let n = 1u8;
let n = n << 8;
let n = n << 9; //~ ERROR: bitshift exceeds the type's number of bits
let n = n << 7;
let n = n << 8; //~ ERROR: bitshift exceeds the type's number of bits

let n = 1u8 << -9; //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u8 << -8; //~ ERROR: bitshift exceeds the type's number of bits

let n = 1u8 << (4+4);
let n = 1u8 << (4+5); //~ ERROR: bitshift exceeds the type's number of bits
let n = 1u8 << (4+3);
let n = 1u8 << (4+4); //~ ERROR: bitshift exceeds the type's number of bits
}

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