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| author | Ralf Jung <post@ralfj.de> | 2019-11-22 22:04:22 +0100 |
|---|---|---|
| committer | Ralf Jung <post@ralfj.de> | 2019-11-22 22:04:22 +0100 |
| commit | be079117f068af74a133dcaaae33ed495f035cc2 (patch) | |
| tree | 6cf2ac7b24b26ec58da4a6fc14a600f72f33c328 | |
| parent | 083b5a0a1bb3b2ee0873697ebf37e88d85faa3e5 (diff) | |
| download | rust-be079117f068af74a133dcaaae33ed495f035cc2.tar.gz rust-be079117f068af74a133dcaaae33ed495f035cc2.zip | |
remove the 'dereferenceable' attribute from Box
| -rw-r--r-- | src/librustc/ty/layout.rs | 8 | ||||
| -rw-r--r-- | src/librustc_target/abi/call/mod.rs | 1 | ||||
| -rw-r--r-- | src/test/codegen/function-arguments.rs | 4 |
3 files changed, 11 insertions, 2 deletions
diff --git a/src/librustc/ty/layout.rs b/src/librustc/ty/layout.rs index b6050a5caf1..e14a78a8c44 100644 --- a/src/librustc/ty/layout.rs +++ b/src/librustc/ty/layout.rs @@ -2526,9 +2526,15 @@ where if let Some(pointee) = layout.pointee_info_at(cx, offset) { if let Some(kind) = pointee.safe { - attrs.pointee_size = pointee.size; attrs.pointee_align = Some(pointee.align); + // `Box` (`UniqueBorrowed`) are not necessarily dereferencable + // for the entire duration of the function, so set their size to 0. + attrs.pointee_size = match kind { + PointerKind::UniqueOwned => Size::ZERO, + _ => pointee.size + }; + // `Box` pointer parameters never alias because ownership is transferred // `&mut` pointer parameters never alias other parameters, // or mutable global data diff --git a/src/librustc_target/abi/call/mod.rs b/src/librustc_target/abi/call/mod.rs index aced12aa32a..1b55676fe4f 100644 --- a/src/librustc_target/abi/call/mod.rs +++ b/src/librustc_target/abi/call/mod.rs @@ -69,6 +69,7 @@ mod attr_impl { #[derive(Copy, Clone, PartialEq, Eq, Debug)] pub struct ArgAttributes { pub regular: ArgAttribute, + /// The dereferenceable size of the pointee. pub pointee_size: Size, pub pointee_align: Option<Align> } diff --git a/src/test/codegen/function-arguments.rs b/src/test/codegen/function-arguments.rs index 7e1791cd4f2..5c9aa48c0a5 100644 --- a/src/test/codegen/function-arguments.rs +++ b/src/test/codegen/function-arguments.rs @@ -65,7 +65,9 @@ pub fn indirect_struct(_: S) { pub fn borrowed_struct(_: &S) { } -// CHECK: noalias align 4 dereferenceable(4) i32* @_box(i32* noalias align 4 dereferenceable(4) %x) +// `Box` can get deallocated during execution of the function, so it should +// not get `dereferenceable`. +// CHECK: noalias nonnull align 4 i32* @_box(i32* noalias nonnull align 4 %x) #[no_mangle] pub fn _box(x: Box<i32>) -> Box<i32> { x |