rustc_codegen_llvm: Add a new 'pc' option to branch-protection
Add a new 'pc' option to -Z branch-protection for aarch64 that enables the use of PC as a diversifier in PAC branch protection code.
When the pauth-lr target feature is enabled in combination with -Z branch-protection=pac-ret,pc, the new 9.5-a instructions (pacibsppc, retaasppc, etc) will be generated.
make codegen help output more consistent
The output of `rustc -C help` generally has one option per line. There was one exception because of a (presumably) forgotten line continuation escape.
Add a new 'pc' option to -Z branch-protection for aarch64 that
enables the use of PC as a diversifier in PAC branch protection code.
When the pauth-lr target feature is enabled in combination
with -Z branch-protection=pac-ret,pc, the new 9.5-a instructions
(pacibsppc, retaasppc, etc) will be generated.
deprecate -Csoft-float because it is unsound (and not fixable)
See https://github.com/rust-lang/rust/issues/129893 for details. The general sentiment there seems to be that this flag has no use and sound alternatives exist, so let's add this warning and see if anyone out there disagrees.
Also show a different warning on targets where it does nothing (as documented since https://github.com/rust-lang/rust/pull/36261): it seems to correspond to `-mfloat-abi` in GCC/clang, which is an ARM-specific option. To be really sure it does nothing, only forward the flag to LLVM for eabihf targets. This should not change behavior but makes me sleep better ;)
Add -Z small-data-threshold
This flag allows specifying the threshold size above which LLVM should not consider placing small objects in a `.sdata` or `.sbss` section.
Support is indicated in the target options via the
small-data-threshold-support target option, which can indicate either an
LLVM argument or an LLVM module flag. To avoid duplicate specifications
in a large number of targets, the default value for support is
DefaultForArch, which is translated to a concrete value according to the
target's architecture.
This flag allows specifying the threshold size above which LLVM should
not consider placing small objects in a .sdata or .sbss section.
Support is indicated in the target options via the
small-data-threshold-support target option, which can indicate either an
LLVM argument or an LLVM module flag. To avoid duplicate specifications
in a large number of targets, the default value for support is
DefaultForArch, which is translated to a concrete value according to the
target's architecture.
We want to allow setting this on the CLI, override it only in MIR
passes, and disable it altogether in mir-opt tests.
The default value is "only for NLL MIR dumps", which is considered off
for all intents and purposes, except for `rustc_borrowck` when an NLL
MIR dump is requested.
Use more slice patterns inside the compiler
Nothing super noteworthy. Just replacing the common 'fragile' pattern of "length check followed by indexing or unwrap" with slice patterns for legibility and 'robustness'.
r? ghost
Gate the type length limit check behind a nightly flag
Effectively disables the type length limit by introducing a `-Zenforce-type-length-limit` which defaults to **`false`**, since making the length limit actually be enforced ended up having a worse fallout than expected. We still keep the code around, but the type length limit attr is now a noop (except for its usage in some diagnostics code?).
r? `@lcnr` -- up to you to decide what team consensus we need here since this reverses an FCP decision.
Reopens#125460 (if we decide to reopen it or keep it closed)
Effectively reverses the decision FCP'd in #125507Closes#127346
Ignore allocation bytes in some mir-opt tests
This adds `rustc -Zdump-mir-exclude-alloc-bytes` to skip writing allocation bytes in MIR dumps, and applies it to tests that were failing on s390x due to its big-endian byte order.
Fixes#126261
Since this codegen flag now only controls LLVM-generated comments rather than
all assembly comments, make the name more accurate (and also match Clang).
In 126578 we ended up with more binary size increases than expected.
This change attempts to avoid inlining large things into small things, to avoid that kind of increase, in cases when top-down inlining will still be able to do that inlining later.
`-Z patchable-function-entry` works like `-fpatchable-function-entry`
on clang/gcc. The arguments are total nop count and function offset.
See MCP rust-lang/compiler-team#704
Deprecate no-op codegen option `-Cinline-threshold=...`
This deprecates `-Cinline-threshold` since using it has no effect. This has been the case since the new LLVM pass manager started being used, more than 2 years ago.
Recommend using `-Cllvm-args=--inline-threshold=...` instead.
Closes#89742 which is E-help-wanted.
