Closes#8506.
The `trans::adt` code for statics uses fields with `C_undef` values to
insert alignment padding (because LLVM's own alignment padding isn't
always sufficient for aggregate constants), and assumes that all fields
in the actual Rust value are represented by non-undef LLVM values, to
distinguish them from that padding.
But for nullable pointer enums, if non-null variant has fields other
than the pointer used as the discriminant, they would be set to undef in
the null case, to reflect that they're never accessed.
To avoid the obvious conflict between these two items, the latter undefs
were wrapped in unary LLVM structs to distinguish them from the former
undefs. Except this doesn't actually work -- LLVM, not unreasonably,
treats the "wrapped undef" as a regular undef.
So this commit just sets all fields to null in the null pointer case of
a nullable pointer enum static, because the other fields don't really
need to be undef in the first place.
Error messages cleaned in librustc/middle
Error messages cleaned in libsyntax
Error messages cleaned in libsyntax more agressively
Error messages cleaned in librustc more aggressively
Fixed affected tests
Fixed other failing tests
Last failing tests fixed
Major changes:
- Define temporary scopes in a syntax-based way that basically defaults
to the innermost statement or conditional block, except for in
a `let` initializer, where we default to the innermost block. Rules
are documented in the code, but not in the manual (yet).
See new test run-pass/cleanup-value-scopes.rs for examples.
- Refactors Datum to better define cleanup roles.
- Refactor cleanup scopes to not be tied to basic blocks, permitting
us to have a very large number of scopes (one per AST node).
- Introduce nascent documentation in trans/doc.rs covering datums and
cleanup in a more comprehensive way.
That is, if you have an enum type that is subject to the nullable
pointer optimization, but the null variant has a nonzero number of
fields, and you declare a static whose value is of that variant, then
that used to be an ICE but this change fixes it.
This is needed so that the FFI works as expected on platforms that don't
flatten aggregates the way the AMD64 ABI does, especially for `#[repr(C)]`.
This moves more of `type_of` into `trans::adt`, because the type might
or might not be an LLVM struct.
The previous implementation, when combined with small discriminants and
immediate types, caused problems for types like `Either<u8, i16>` which
are now small enough to be immediate and can have fields intersecting
the highest-alignment variant's alignment padding (which LLVM doesn't
preserve). So let's not do that.
Note that raising an error during trans doesn't stop the compile or cause
rustc to exit with a failure status, currently, so this is of more than
cosmetic importance.
Allows an enum with a discriminant to use any of the primitive integer
types to store it. By default the smallest usable type is chosen, but
this can be overridden with an attribute: `#[repr(int)]` etc., or
`#[repr(C)]` to match the target's C ABI for the equivalent C enum.
This commit breaks a few things, due to transmutes that now no longer
match in size, or u8 enums being passed to C that expects int, or
reflection; later commits on this branch fix them.
- Made naming schemes consistent between Option, Result and Either
- Changed Options Add implementation to work like the maybe monad (return None if any of the inputs is None)
- Removed duplicate Option::get and renamed all related functions to use the term `unwrap` instead
Infers type of constants used as discriminants and ensures they are
integral, instead of forcing them to be a signed integer.
Also, stores discriminant values as uint instead of int interally and
deals with related fallout.
Fixes issue #7994
I removed the `static-method-test.rs` test because it was heavily based
on `BaseIter` and there are plenty of other more complex uses of static
methods anyway.
The removed test for issue #2611 is well covered by the `std::iterator`
module itself.
This adds the `count` method to `IteratorUtil` to replace `EqIter`.
Moves all the remaining functions that could reasonably be methods to be methods, except for some FFI ones (which I believe @erickt is working on, possibly) and `each_split_within`, since I'm not really sure the details of it (I believe @kimundi wrote the current implementation, so maybe he could convert it to an external iterator method on `StrSlice`, e.g. `word_wrap_iter(&self) -> WordWrapIterator<'self>`, where `WordWrapIterator` impls `Iterator<&'self str>`. It probably won't be too hard, since it's already a state machine.)
This also cleans up the comparison impls for the string types, except I'm not sure how the lang items `eq_str` and `eq_str_uniq` need to be handled, so they (`eq_slice` and `eq`) remain stand-alone functions.
Remove all the explicit @mut-fields from CrateContext, though many
fields are still @-ptrs.
This required changing every single function call that explicitly
took a @CrateContext, so I took advantage and changed as many as I
could get away with to &-ptrs or &mut ptrs.
This fixes the strange random crashes in compile-fail tests.
This reverts commit 96cd61ad03.
Conflicts:
src/librustc/driver/driver.rs
src/libstd/str.rs
src/libsyntax/ext/quote.rs
Cases like `Either<@int,()>` have a null case with at most one value but
a nonzero number of fields; if we misreport this, then bad things can
happen inside of, for example, pattern matching.
Closes#6117.
A struct (inc. tuple struct) can be annotated with #[packed], so that there
is no padding between its elements, like GCC's `__attribute__((packed))`.
Closes#1704
The only thing we really lose is that C-like enums with one variant and a
non-zero discriminant now take up space, but I do not think this is a
common usage. As previously noted, that was mostly there for
transitional compatibility with the pre-adt.rs codebase.
Out goes the extra layer of struct wrapping; the destructedness flag is
added to the end of the struct. This means that, if the struct
previously had alignment padding at the end, the flag will live there
instead of increasing the struct size.
Note that in the ByValue case (which can't happen? yet?) we're still
effectively bitcasting, I think. So this change adds a way to assert
that that's safe.
Note also, for future reference, that LLVM's instcombine pass will turn
a bitcast into a GEP(0, 0, ...) if possible.
This change remains separate from the addition of adt.rs, even though
it's necessary for compatibility with pre-trans::adt representation,
to serve as an example of a change to the representation logic.
Later changes on this branch adapt the rest of rustc::middle::trans
to use this module instead of scattered hard-coded knowledge of
representations; a few of them also have improvements or cleanup for
adt.rs (and many added comments) that weren't drastic enough to justify
changing history to move them into this commit.
