Use FxHash{Map,Set} instead of the default Hash{Map,Set} everywhere in rustc.
Most of the compiler uses the `Fx` hasher but some places ended up with the default one.
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
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 | | |
This reworks the force-frame-pointer PR to explicitly only consider the
value of the flag if it is provided, and use a target default otherwise.
Something that was tried but not kept was renaming the flag to
`frame-pointer`, because for flag `frame-pointer=no`, there is no
guarante, that LLVM will elide *all* the frame pointers; oposite of what
the literal reading of the flag would suggest.
We apparently used to generate bad/incomplete debug info causing
debuggers not to find symbols of stack allocated variables. This was
somehow worked around by having frame pointers.
With the current codegen, this seems no longer necessary, so we can
remove the code that force-enables frame pointers whenever debug info
is requested.
Since certain situations, like profiling code profit from having frame
pointers, we add a -Cforce-frame-pointers flag to always enable frame
pointers.
Fixes#11906
