Fix transmutes between pointers in different address spaces (e.g. fn ptrs on AVR...
source link: https://github.com/rust-lang/rust/pull/105578
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Contributor
erikdesjardins
commented
Dec 11, 2022
Currently, this causes a verifier error (https://godbolt.org/z/YYohed4bj), since it uses bitcast, which can't convert between address spaces.
Uncovered due to #105545 (comment)
r? @bjorn3
added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
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// It doesn't matter precisely how this is codegenned (as a roundtrip through memory or an addrspacecast), |
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// as long as it doesn't cause a verifier error, e.g. by using `bitcast` (which was the case before). |
Contributor
Author
erikdesjardins
Dec 11, 2022
This is codegenned as
%0 = addrspacecast ptr %x to ptr addrspace(1)I can add a check line instead if you'd prefer
assert_eq!(src.layout.size, dst.layout.size); |
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// NOTE(eddyb) the `from_immediate` and `to_immediate_scalar` |
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// conversions allow handling `bool`s the same as `u8`s. |
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let src = bx.from_immediate(src.immediate()); |
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let src_as_dst = bx.bitcast(src, bx.backend_type(dst.layout)); |
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// LLVM also doesn't like `bitcast`s between pointers in different address spaces. |
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let src_as_dst = if src_is_ptr { |
Contributor
bjorn3
Dec 13, 2022
What if the from type is a pointer and the to type is an integer? Does pointercast work for that?
Contributor
Author
erikdesjardins
Dec 13, 2022
It doesn't, but that's not possible here due to src_is_ptr == dst_is_ptr above. I can change this line to src_is_ptr && dst_is_ptr if that would be clearer
Contributor
bjorn3
Dec 14, 2022
Right
Contributor
bjorn3 commented Dec 14, 2022
|
@bors r+ |
Contributor
bors commented Dec 14, 2022
Commit added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion.
and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties.
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