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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /src/test/ui/structs-enums/codegen-tag-static-padding.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/test/ui/structs-enums/codegen-tag-static-padding.rs')
-rw-r--r-- | src/test/ui/structs-enums/codegen-tag-static-padding.rs | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/src/test/ui/structs-enums/codegen-tag-static-padding.rs b/src/test/ui/structs-enums/codegen-tag-static-padding.rs new file mode 100644 index 000000000..8aa087c01 --- /dev/null +++ b/src/test/ui/structs-enums/codegen-tag-static-padding.rs @@ -0,0 +1,59 @@ +// run-pass +#![allow(non_upper_case_globals)] + +// Issue #13186 + +// For simplicity of explanations assuming code is compiled for x86_64 +// Linux ABI. + +// Size of TestOption<u64> is 16, and alignment of TestOption<u64> is 8. +// Size of u8 is 1, and alignment of u8 is 1. +// So size of Request is 24, and alignment of Request must be 8: +// the maximum alignment of its fields. +// Last 7 bytes of Request struct are not occupied by any fields. + + + +enum TestOption<T> { + TestNone, + TestSome(T), +} + +pub struct Request { + foo: TestOption<u64>, + bar: u8, +} + +fn default_instance() -> &'static Request { + static instance: Request = Request { + // LLVM does not allow to specify alignment of expressions, thus + // alignment of `foo` in constant is 1, not 8. + foo: TestOption::TestNone, + bar: 17, + // Space after last field is not occupied by any data, but it is + // reserved to make struct aligned properly. If compiler does + // not insert padding after last field when emitting constant, + // size of struct may be not equal to size of struct, and + // compiler crashes in internal assertion check. + }; + &instance +} + +fn non_default_instance() -> &'static Request { + static instance: Request = Request { + foo: TestOption::TestSome(0x1020304050607080), + bar: 19, + }; + &instance +} + +pub fn main() { + match default_instance() { + &Request { foo: TestOption::TestNone, bar: 17 } => {}, + _ => panic!(), + }; + match non_default_instance() { + &Request { foo: TestOption::TestSome(0x1020304050607080), bar: 19 } => {}, + _ => panic!(), + }; +} |