This fixes a regression from #53031 where specifying `-C target-cpu=native` is
printing a lot of warnings from LLVM about `native` being an unknown CPU. It
turns out that `native` is indeed an unknown CPU and we have to perform a
mapping to an actual CPU name, but this mapping is only performed in one
location rather than all locations we inform LLVM about the target CPU.
This commit centralizes the mapping of `native` to LLVM's value of the native
CPU, ensuring that all locations we inform LLVM about the `target-cpu` it's
never `native`.
Closes#53322
try to infer linker flavor from linker name and vice versa
This is a second take on PR #50359 that implements the logic proposed in https://github.com/rust-lang/rust/pull/50359#pullrequestreview-116663121
With this change it would become possible to link `thumb*` binaries using GNU's LD on stable as `-C linker=arm-none-eabi-ld` would be enough to change both the linker and the linker flavor from their default values of `arm-none-eabi-gcc` and `gcc`.
To link `thumb*` binaries using rustc's LLD on stable `-Z linker-flavor` would need to be stabilized as `-C linker=rust-lld -Z linker-flavor=ld.lld` are both required to change the linker and the linker flavor, but this PR doesn't propose that. We would probably need some sort of stability guarantee around `rust-lld`'s name and availability to make linking with rustc's LLD truly stable.
With this change it would also be possible to link `thumb*` binaries using a system installed LLD on stable using the `-C linker=ld.lld` flag (provided that `ld.lld` is a symlink to the system installed LLD).
r? @alexcrichton
Previously linker diagnostic were being hidden when two modules were linked
together but failed to link. This commit fixes the situation by ensuring that we
have a diagnostic handler installed and also adds support for handling linker
diagnostics.
Remove `ty_to_def_id`
fixes https://github.com/rust-lang/rust/issues/52341
The uses were mostly convenience and generally "too powerful" (would also have worked for types that weren't interesting at the use site)
r? @eddyb
Preliminary work for incremental ThinLTO.
Since implementing incremental ThinLTO is a bit more involved than I initially thought, I'm splitting out some of the things that already work. This PR (1) adds a way accessing some ThinLTO information in `rustc` and (2) does some cleanup around CGU/object file naming (which makes things quite a bit nicer).
This is probably best reviewed one commit at a time.
Disable LLVM verification by default
Currently -Z no-verify only controls IR verification prior to LLVM codegen, while verification is performed unconditionally both before and after linking with (Thin)LTO.
Also wondering what the sentiment is on disabling verification by default (and e.g. only enabling it on ALT builds with assertions). This does not seem terribly useful outside of rustc development and it does seem to show up in profiles (at something like 3%).
**EDIT:** A table showing the various configurations and what is enabled when.
| Configuration | Dynamic verification performed | LLVM static assertions compiled in |
| --- | --- | --- |
| alt builds | | yes |
| nightly builds | | no |
| stable builds | | no |
| CI builds | | |
| dev builds in a checkout | | |
Currently -Z no-verify only controls IR verification prior to
LLVM codegen, while verification is performed unconditionally
both before and after linking with (Thin)LTO.
Codegen issues commonly only manifest under specific circumstances,
e.g. if multiple codegen units are used and ThinLTO is enabled.
However, these configuration are threaded, making the use of LLVM
debugging facilities hard, as output is interleaved.
This patch adds a -Z no-parallel-llvm flag, which allows disabling
parallelization of codegen and linking, while otherwise preserving
behavior with regard to codegen units and LTO.
