Rollup merge of #114335 - RalfJung:ptr_comparisons, r=oli-obk

fix and extend ptr_comparison test

r? ```@oli-obk```
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Nilstrieb 2023-08-02 13:46:55 +02:00 committed by GitHub
commit 60399a888d
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2 changed files with 8 additions and 68 deletions

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@ -1,8 +1,5 @@
// compile-flags: --crate-type=lib
// normalize-stderr-32bit: "8 bytes" -> "$$TWO_WORDS bytes"
// normalize-stderr-64bit: "16 bytes" -> "$$TWO_WORDS bytes"
// normalize-stderr-32bit: "size 4" -> "size $$WORD"
// normalize-stderr-64bit: "size 8" -> "size $$WORD"
// check-pass
#![feature(
core_intrinsics,
@ -34,30 +31,13 @@ check!(ne, unsafe { (FOO as *const usize as *const u8).offset(3) }, 0);
// We want pointers to be equal to themselves, but aren't checking this yet because
// there are some open questions (e.g. whether function pointers to the same function
// compare equal, they don't necessarily at runtime).
// The case tested here should work eventually, but does not work yet.
// compare equal: they don't necessarily do at runtime).
check!(!, FOO as *const _, FOO as *const _);
// aside from 0, these pointers might end up pretty much anywhere.
check!(!, FOO as *const _, 1); // this one could be `ne` by taking into account alignment
check!(!, FOO as *const _, 1024);
///////////////////////////////////////////////////////////////////////////////
// If any of the below start compiling, make sure to add a `check` test for it.
// These invocations exist as canaries so we don't forget to check that the
// behaviour of `guaranteed_eq` and `guaranteed_ne` is still correct.
// All of these try to obtain an out of bounds pointer in some manner. If we
// can create out of bounds pointers, we can offset a pointer far enough that
// at runtime it would be zero and at compile-time it would not be zero.
const _: *const usize = unsafe { (FOO as *const usize).offset(2) };
const _: *const u8 =
unsafe { std::ptr::addr_of!((*(FOO as *const usize as *const [u8; 1000]))[999]) };
//~^ ERROR evaluation of constant value failed
//~| out-of-bounds
const _: usize = unsafe { std::mem::transmute::<*const usize, usize>(FOO) + 4 };
//~^ ERROR evaluation of constant value failed
//~| unable to turn pointer into raw bytes
const _: usize = unsafe { *std::mem::transmute::<&&usize, &usize>(&FOO) + 4 };
//~^ ERROR evaluation of constant value failed
//~| unable to turn pointer into raw bytes
// When pointers go out-of-bounds, they *might* become null, so these comparions cannot work.
check!(!, unsafe { (FOO as *const usize).wrapping_add(2) }, 0);
check!(!, unsafe { (FOO as *const usize).wrapping_sub(1) }, 0);

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@ -1,40 +0,0 @@
error[E0080]: evaluation of constant value failed
--> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
|
= note: out-of-bounds pointer arithmetic: alloc3 has size $WORD, so pointer to $TWO_WORDS bytes starting at offset 0 is out-of-bounds
|
note: inside `ptr::const_ptr::<impl *const usize>::offset`
--> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
note: inside `_`
--> $DIR/ptr_comparisons.rs:50:34
|
LL | const _: *const usize = unsafe { (FOO as *const usize).offset(2) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0080]: evaluation of constant value failed
--> $DIR/ptr_comparisons.rs:53:33
|
LL | unsafe { std::ptr::addr_of!((*(FOO as *const usize as *const [u8; 1000]))[999]) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ dereferencing pointer failed: alloc3 has size $WORD, so pointer to 1000 bytes starting at offset 0 is out-of-bounds
error[E0080]: evaluation of constant value failed
--> $DIR/ptr_comparisons.rs:57:27
|
LL | const _: usize = unsafe { std::mem::transmute::<*const usize, usize>(FOO) + 4 };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
|
= help: this code performed an operation that depends on the underlying bytes representing a pointer
= help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
error[E0080]: evaluation of constant value failed
--> $DIR/ptr_comparisons.rs:61:27
|
LL | const _: usize = unsafe { *std::mem::transmute::<&&usize, &usize>(&FOO) + 4 };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
|
= help: this code performed an operation that depends on the underlying bytes representing a pointer
= help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0080`.