kcfi: only reify trait methods when dyn-compatible #146865
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@folkertdev Thanks for fixing this! |
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ping @rcvalle, I think you're the only person that can review this really? |
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@folkertdev sorry for the delay. Thank you for you for your time and working on this! Much appreciated. |
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@bors r+ |
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…patible, r=rcvalle kcfi: only reify trait methods when dyn-compatible fixes rust-lang#146853 Only generate a `ReifyShim` for trait method calls if the trait is dyn-compatible. Until now kcfi would generate a `ReifyShim` whenever a trait method was cast to a function pointer. But technically the shim is only needed for dyn-compatible traits (where the method might end up in a vtable). Up to this point that was only slightly inefficient, but in combination with c-variadic trait methods it is wrong. For c-variadic trait methods the generated shim is incorrect, and that is why c-variadic methods make a trait no longer dyn-compatible: we should simply never generate a `ReifyShim` that is c-variadic. With this change the documentation on `ReifyReason` is now actually correct: > If KCFI is enabled, creating a function pointer from a method on a dyn-compatible trait. This includes the case of converting `::call`-like methods on closure-likes to function pointers. cc `@maurer` `@workingjubilee` r? `@rcvalle`
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Rollup of 7 pull requests Successful merges: - #143900 ([rustdoc] Correctly handle `should_panic` doctest attribute and fix `--no-run` test flag on the 2024 edition) - #145608 (Prevent downstream `impl DerefMut for Pin<LocalType>`) - #146865 (kcfi: only reify trait methods when dyn-compatible) - #147390 (Use globals instead of metadata for std::autodiff) - #147398 (Fix; correct placement of type inference error for method calls) - #147431 (compiletest: Read the whole test file before parsing directives) - #147433 (Fix doc comment) r? `@ghost` `@rustbot` modify labels: rollup
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…patible, r=rcvalle kcfi: only reify trait methods when dyn-compatible fixes rust-lang#146853 Only generate a `ReifyShim` for trait method calls if the trait is dyn-compatible. Until now kcfi would generate a `ReifyShim` whenever a trait method was cast to a function pointer. But technically the shim is only needed for dyn-compatible traits (where the method might end up in a vtable). Up to this point that was only slightly inefficient, but in combination with c-variadic trait methods it is wrong. For c-variadic trait methods the generated shim is incorrect, and that is why c-variadic methods make a trait no longer dyn-compatible: we should simply never generate a `ReifyShim` that is c-variadic. With this change the documentation on `ReifyReason` is now actually correct: > If KCFI is enabled, creating a function pointer from a method on a dyn-compatible trait. This includes the case of converting `::call`-like methods on closure-likes to function pointers. cc ``@maurer`` ``@workingjubilee`` r? ``@rcvalle``
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Rollup of 8 pull requests Successful merges: - #145608 (Prevent downstream `impl DerefMut for Pin<LocalType>`) - #146865 (kcfi: only reify trait methods when dyn-compatible) - #147205 (Add a new `wasm32-wasip3` target to Rust) - #147390 (Use globals instead of metadata for std::autodiff) - #147398 (Fix; correct placement of type inference error for method calls) - #147422 (collect-license-metadata: Print a diff of the expected output) - #147431 (compiletest: Read the whole test file before parsing directives) - #147433 (Fix doc comment) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup of 8 pull requests Successful merges: - #145608 (Prevent downstream `impl DerefMut for Pin<LocalType>`) - #146865 (kcfi: only reify trait methods when dyn-compatible) - #147205 (Add a new `wasm32-wasip3` target to Rust) - #147390 (Use globals instead of metadata for std::autodiff) - #147398 (Fix; correct placement of type inference error for method calls) - #147422 (collect-license-metadata: Print a diff of the expected output) - #147431 (compiletest: Read the whole test file before parsing directives) - #147433 (Fix doc comment) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup of 8 pull requests Successful merges: - #146865 (kcfi: only reify trait methods when dyn-compatible) - #147205 (Add a new `wasm32-wasip3` target to Rust) - #147322 (cg_llvm: Consistently import `llvm::Type` and `llvm::Value`) - #147398 (Fix; correct placement of type inference error for method calls) - #147410 (Update `S-waiting-on-team` refs to new `S-waiting-on-{team}` labels) - #147422 (collect-license-metadata: Print a diff of the expected output) - #147431 (compiletest: Read the whole test file before parsing directives) - #147433 (Fix doc comment) Failed merges: - #147390 (Use globals instead of metadata for std::autodiff) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of #146865 - folkertdev:kcfi-only-reify-dyn-compatible, r=rcvalle kcfi: only reify trait methods when dyn-compatible fixes #146853 Only generate a `ReifyShim` for trait method calls if the trait is dyn-compatible. Until now kcfi would generate a `ReifyShim` whenever a trait method was cast to a function pointer. But technically the shim is only needed for dyn-compatible traits (where the method might end up in a vtable). Up to this point that was only slightly inefficient, but in combination with c-variadic trait methods it is wrong. For c-variadic trait methods the generated shim is incorrect, and that is why c-variadic methods make a trait no longer dyn-compatible: we should simply never generate a `ReifyShim` that is c-variadic. With this change the documentation on `ReifyReason` is now actually correct: > If KCFI is enabled, creating a function pointer from a method on a dyn-compatible trait. This includes the case of converting `::call`-like methods on closure-likes to function pointers. cc ```@maurer``` ```@workingjubilee``` r? ```@rcvalle```
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…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#146865 (kcfi: only reify trait methods when dyn-compatible) - rust-lang#147205 (Add a new `wasm32-wasip3` target to Rust) - rust-lang#147322 (cg_llvm: Consistently import `llvm::Type` and `llvm::Value`) - rust-lang#147398 (Fix; correct placement of type inference error for method calls) - rust-lang#147410 (Update `S-waiting-on-team` refs to new `S-waiting-on-{team}` labels) - rust-lang#147422 (collect-license-metadata: Print a diff of the expected output) - rust-lang#147431 (compiletest: Read the whole test file before parsing directives) - rust-lang#147433 (Fix doc comment) Failed merges: - rust-lang#147390 (Use globals instead of metadata for std::autodiff) r? `@ghost` `@rustbot` modify labels: rollup
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fixes #146853
Only generate a
ReifyShimfor trait method calls if the trait is dyn-compatible.Until now kcfi would generate a
ReifyShimwhenever a trait method was cast to a function pointer. But technically the shim is only needed for dyn-compatible traits (where the method might end up in a vtable).Up to this point that was only slightly inefficient, but in combination with c-variadic trait methods it is wrong. For c-variadic trait methods the generated shim is incorrect, and that is why c-variadic methods make a trait no longer dyn-compatible: we should simply never generate a
ReifyShimthat is c-variadic.With this change the documentation on
ReifyReasonis now actually correct:cc @maurer @workingjubilee
r? @rcvalle