rust/compiler/rustc_monomorphize
bors b3df0d7e5e Auto merge of #122580 - saethlin:compiler-builtins-can-panic, r=pnkfelix
"Handle" calls to upstream monomorphizations in compiler_builtins

This is pretty cooked, but I think it works.

compiler-builtins has a long-standing problem that at link time, its rlib cannot contain any calls to `core`. And yet, in codegen we _love_ inserting calls to symbols in `core`, generally from various panic entrypoints.

I intend this PR to attack that problem as completely as possible. When we generate a function call, we now check if we are generating a function call from `compiler_builtins` and whether the callee is a function which was not lowered in the current crate, meaning we will have to link to it.

If those conditions are met, actually generating the call is asking for a linker error. So we don't. If the callee diverges, we lower to an abort with the same behavior as `core::intrinsics::abort`. If the callee does not diverge, we produce an error. This means that compiler-builtins can contain panics, but they'll SIGILL instead of panicking. I made non-diverging calls a compile error because I'm guessing that they'd mostly get into compiler-builtins by someone making a mistake while working on the crate, and compile errors are better than linker errors. We could turn such calls into aborts as well if that's preferred.
2024-03-22 16:55:11 +00:00
..
src Auto merge of #122580 - saethlin:compiler-builtins-can-panic, r=pnkfelix 2024-03-22 16:55:11 +00:00
Cargo.toml Clean up rustc_*/Cargo.toml. 2023-10-30 08:46:02 +11:00
messages.ftl Stop mentioning internal lang items in no_std binary errors 2024-01-10 21:18:54 +01:00