Hello,
I am working on a verifier for Rust, based on the generated LLVM code. I
am having an issue with code generated similar to the following
struct Point {
pub x: u32,
pub y: u32
}
fn double_point(p: Point) -> Point {
Point { x: 2*p.x, y: 2*p.y }
}
fn main() {
let p = Point { x: 2, y: 3 };
let q = double_point(p);
assert!(q.x == 4 && q.y == 6);
}
The call to the double_point function is what causes the issue, as shown
in the following generated llvm-ir code
%8 = bitcast %Point* %arg to i64*
%9 = load i64, i64* %8, align 4
%10 = call i64 @_ZN5point12double_point17h4b5ca79567fdc22dE(i64 %9)
store i64 %10, i64* %abi_cast
In the verifier's default mode, reads from the i64 don't work correctly,
giving an assertion violation. This code works if the Point structure
uses 64-bit ints instead, since no packing occurs.
My question is: is there is a way to prevent the compiler from
bit-casting the structure to an integer? I am using a December 2016
nightly compiler, and have tried disabling all optimizations.
Thanks,
Mark
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