Reduce maximum repr(align(N)) to 2^29
The current maximum `repr(align(N))` alignment is larger than the maximum alignment accepted by LLVM, which can cause issues for huge values of `N`, as seen in #49492. Fixes#49492.
r? @rkruppe
Fix a warning in libcore on 16bit targets.
This code is assuming that usize >= 32bits, but it is not the case on
16bit targets. It is producing a warning that can fail the compilation
on MSP430 if deny(warnings) is enabled.
It is very unlikely that someone would actually use this code on
a microcontroller, but since unicode was merged into libcore we
have to compile it on 16bit targets.
I've tried to make sure that the code stays the same on x86,
here is an assembly comparison: https://godbolt.org/g/wFw7dZ
r? @SimonSapin
This avoids converting every char to \u{...} form, which bloats the
resulting strings unnecessarily. It also provides consistency with the
existing escape_default() calls in LitKind::token() used for raw
string literals, char literals, and raw byte char literals.
There are two benefits from this change.
- Compilation is faster. Most of the rustc-perf benchmarks see a
non-trivial speedup, particularly for incremental rebuilds, with the
best speedup over 13%, and multiple others over 10%.
- Generated rlibs are smaller. An extreme example is libfutures.rlib,
which shrinks from 2073306 bytes to 1765927 bytes, a 15% reduction.
Fix an unresolved import issue with enabled `use_extern_macros`
This is a kinda ugly special-purpose solution that will break if we suddenly add a fourth namespace, but I hope to come up with something more general if I get to import resolution refactoring this summer.
Fixes https://github.com/rust-lang/rust/issues/50187 thus removing a blocker for stabilization of `use_extern_macros`
Correct initial field alignment for repr(C)/repr(int)
Fixes#50098 following https://github.com/rust-lang/rust/issues/50098#issuecomment-385497333.
(I wasn't sure which kind of test was best suited here — I picked run-pass simply because that was convenient, but if codegen is more appropriate, let me know and I'll change it.)
r? @eddyb
Treat generators as if they have an arbitrary destructor
Conservatively assume dropping a generator touches its upvars, via locals' destructors.
Fix#49918
rustc: return iterators from Terminator(Kind)::successors(_mut).
Minor cleanup (and potentially speedup) prompted by @nnethercote's `SmallVec` experiments.
This PR assumes `.count()` and `.nth(i)` on `iter::Chain<option::IntoIter, slice::Iter(Mut)>` are `O(1)`, but otherwise all of the uses appear to immediately iterate through the successors.
r? @nikomatsakis
This is meant to address rust-lang/rust#49918.
Review feedback: put back comment justifying skipping interior traversal.
Review feedback: dropck generators like trait objects: all their upvars must
outlive the generator itself, so just create a DtorckConstraint saying so.
Module experiments: Add one more prelude layer for extern crate names passed with `--extern`
Implements one item from https://internals.rust-lang.org/t/the-great-module-adventure-continues/6678/183
When some name is looked up in lexical scope (`name`, i.e. not module-relative scope `some_mod::name` or `::name`), it's searched roughly in the next order:
- local variables
- items in unnamed blocks
- items in the current module
- ✨ NEW! ✨ crate names passed with `--extern` ("extern prelude")
- standard library prelude (`Vec`, `drop`)
- language prelude (built-in types like `u8`, `str`, etc)
The last two layers contain a limited set of names controlled by us and not arbitrary user-defined names like upper layers. We want to be able to add new names into these two layers without breaking user code, so "extern prelude" names have higher priority than std prelude and built-in types.
This is a one-time breaking change, that's why it would be nice to run this through crater.
Practical impact is expected to be minimal though due to stylistic reasons (there are not many `Uppercase` crates) and due to the way how primitive types are resolved (https://github.com/rust-lang/rust/pull/32131).
This code is assuming that usize >= 32bits, but it is not the case on
16bit targets. It is producing a warning that will fail the compilation
on MSP430 if deny(warnings) is enabled.
It is very unlikely that someone would actually use this code on
a microcontroller, but since unicode was merged into libcore we
have compile it on 16bit targets.
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
move skolemized regions into global tcx
Experimental branch to move skolemized regions into global tcx. This is probably not what we want long term but may be convenient to unblock @sgrif in the short term.
I'd like to do a perf run, though the main concern I guess would be memory usage.
r? @eddyb
