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Rust Remove SafeSliceAccess for Arrays, and fix miri. (#6592)

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* Fix Miri flag passing and bump Rust version.

* Fix Miri problems from Arrays PR.

SafeSliceAccess was removed for Arrays. It's kind of unsound.
It has two properties:
1. EndianSafe
2. Alignment 1

We only need 1. in create_vector_direct to memcpy data.
We both 1. and 2. for accessing things with slices as buffers are built on &[u8]
which is unaligned. Conditional compilation implements
SafeSliceAccess for >1byte scalars (like f32) on LittleEndian machines
which is wrong since they don't satisfy 2.

This UB is still accessible for Vectors (though not exercised our
tests) as it implements SafeSliceAccess. I'll fix this later by
splitting SafeSliceAccess into its 2 properties.

Co-authored-by: Casper Neo <cneo@google.com>
This commit is contained in:
Casper
2021-04-26 19:28:25 -04:00
committed by GitHub
parent c24031c36b
commit c87179e73e
5 changed files with 17 additions and 21 deletions
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11
tests/rust_usage_test/tests/arrays_test.rs
View File

@@ -225,8 +225,8 @@ fn verify_struct_array_alignment() {
let array_table = root_as_array_table(buf).unwrap();
let array_struct = array_table.a().unwrap();
let struct_start_ptr = array_struct.0.as_ptr() as usize;
let b_start_ptr = array_struct.b().safe_slice().as_ptr() as usize;
let d_start_ptr = array_struct.d().safe_slice().as_ptr() as usize;
let b_start_ptr = array_struct.b().as_ptr() as usize;
let d_start_ptr = array_struct.d().as_ptr() as usize;
// The T type of b
let b_aln = ::std::mem::align_of::<i32>();
assert_eq!((b_start_ptr - struct_start_ptr) % b_aln, 0);
@@ -272,8 +272,6 @@ mod array_fuzz {
let arr: flatbuffers::Array<$ty, ARRAY_SIZE> = flatbuffers::Array::follow(&test_buf, 0);
let got: [$ty; ARRAY_SIZE] = arr.into();
assert_eq!(got, xs.0);
#[cfg(target_endian = "little")]
assert_eq!(arr.safe_slice(), xs.0);
}
#[test]
fn $test_name() {
@@ -317,13 +315,10 @@ mod array_fuzz {
let arr: flatbuffers::Array<NestedStruct, ARRAY_SIZE> = flatbuffers::Array::follow(&test_buf, 0);
let got: [&NestedStruct; ARRAY_SIZE] = arr.into();
assert_eq!(got, native_struct_array);
let arr_slice = arr.safe_slice();
for i in 0..ARRAY_SIZE {
assert_eq!(arr_slice[i], *native_struct_array[i]);
}
}
#[test]
#[cfg(not(miri))] // slow.
fn test_struct() {
quickcheck::QuickCheck::new().max_tests(MAX_TESTS).quickcheck(prop_struct as fn(FakeArray<NestedStructWrapper, ARRAY_SIZE>));
}

1
tests/rust_usage_test/tests/integration_test.rs
View File

@@ -1115,6 +1115,7 @@ mod roundtrip_byteswap {
// fn fuzz_f64() { quickcheck::QuickCheck::new().max_tests(N).quickcheck(prop_f64 as fn(f64)); }
}
#[cfg(not(miri))]
quickcheck! {
fn struct_of_structs(
a_id: u32,