From ac8ce3e3be305fae748fa7e2c98b4bfaa3f1dd88 Mon Sep 17 00:00:00 2001 From: Bastian Kersting Date: Thu, 15 May 2025 19:09:13 +0000 Subject: [PATCH] Insert checks for enum discriminants when debug assertions are enabled Similar to the existing nullpointer and alignment checks, this checks for valid enum discriminants on creation of enums through unsafe transmutes. Essentially this sanitizes patterns like the following: ```rust let val: MyEnum = unsafe { std::mem::transmute(42) }; ``` An extension of this check will be done in a follow-up that explicitly sanitizes for extern enum values that come into Rust from e.g. C/C++. This check is similar to Miri's capabilities of checking for valid construction of enum values. This PR is inspired by saethlin@'s PR https://github.com/rust-lang/rust/pull/104862. Thank you so much for keeping this code up and the detailed comments! I also pair-programmed large parts of this together with vabr-g@. --- src/base.rs | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/src/base.rs b/src/base.rs index 0b641ba64b7a..1b68c6535da5 100644 --- a/src/base.rs +++ b/src/base.rs @@ -407,6 +407,18 @@ fn codegen_fn_body(fx: &mut FunctionCx<'_, '_, '_>, start_block: Block) { source_info.span, ) } + AssertKind::InvalidEnumConstruction(source) => { + let source = codegen_operand(fx, source).load_scalar(fx); + let location = fx.get_caller_location(source_info).load_scalar(fx); + + codegen_panic_inner( + fx, + rustc_hir::LangItem::PanicInvalidEnumConstruction, + &[source, location], + *unwind, + source_info.span, + ) + } _ => { let location = fx.get_caller_location(source_info).load_scalar(fx);