use checked casts and arithmetic in Miri engine
This is unfortunately pretty annoying because we have to cast back and forth between `u64` and `usize` more often that should be necessary, and that cast is considered fallible.
For example, should [this](https://doc.rust-lang.org/nightly/nightly-rustc/rustc/mir/interpret/value/enum.ConstValue.html) really be `usize`?
Also, `LayoutDetails` uses `usize` for field indices, but in Miri we use `u64` to be able to also handle array indexing. Maybe methods like `mplace_field` should be suitably generalized to accept both `u64` and `usize`?
r? @oli-obk Cc @eddyb
Refactor `codegen`
`codegen` in `src/librustc_codegen_llvm/back/write.rs` is long and has complex control flow. These commits refactor it and make it easier to understand.
Because it uses `parse_bool` and defaults to true, it is actually
impossible to set it to false. Inverting its sense to `-Z
no-generate-arange-section` makes it usable.
rustc: keep upvars tupled in {Closure,Generator}Substs.
Previously, each closure/generator capture's (aka "upvar") type was tracked as one "synthetic" type parameter in the closure/generator substs, and figuring out where the parent `fn`'s generics end and the synthetics start involved slicing at `tcx.generics_of(def_id).parent_count`.
Needing to query `generics_of` limited @davidtwco (who wants to compute some `TypeFlags` differently for parent generics vs upvars, and `TyCtxt` is not available there), which is how I got started on this, but it's also possible that the `generics_of` queries are slowing down `{Closure,Generator}Substs` methods.
To give an example, for a `foo::<T, U>::{closure#0}` with captures `x: X` and `y: Y`, substs are:
* before this PR: `[T, U, /*kind*/, /*signature*/, X, Y]`
* after this PR: `[T, U, /*kind*/, /*signature*/, (X, Y)]`
You can see that, with this PR, no matter how many captures, the last 3 entries in the substs (or 5 for a generator) are always the "synthetic" ones, with the last one being the tuple of capture types.
r? @nikomatsakis cc @Zoxc
This adds a missing `!config.obj_is_bitcode` condition to two places
that should have it.
As a result, when `obj_is_bitcode` and `no_integrated_as` are both true,
the compiler will no longer unnecessarily emit asm, convert it to an
object file, and then overwrite that object file with bitcode.
I find the code easier to read if the values in `config` are all used
directly, rather than a mix of `config` values and local variables. It
will also faciliate some of the following commits.
Also, use `config.bitcode_needed()` in one place.
Refactorings to get rid of rustc_codegen_utils
r? @eddyb
cc #45276
After this, the only modules left in `rustc_codegen_utils` are
- `link`: a bunch of linking-related functions (many dealing with file names). These are mostly consumed by save analysis, rustc_driver, rustc_interface, and of course codegen. I assume they live here because we don't want a dependency of save analysis on codegen... Perhaps they can be moved to librustc?
- ~`symbol_names` and `symbol_names_test`: honestly it seems odd that `symbol_names_test` is not a submodule of `symbol_names`. It seems like these could honestly live in their own crate or move to librustc. Already name mangling is exported as the `symbol_name` query.~ (move it to its own crate)
I don't mind doing either of the above as part of this PR or a followup if you want.
Remove some imports to the rustc crate
- When we have `NestedVisitorMap::None`, we use `type Map = dyn intravisit::Map<'v>;` instead of the actual map. This doesn't actually result in dynamic dispatch (in the future we may want to use an associated type default to simplify the code).
- Use `rustc_session::` imports instead of `rustc::{session, lint}`.
r? @Zoxc
Emit 1-based column numbers in debuginfo
* Use byte offsets instead of char position offsets. Resolves#67360.
* Use 1-based offsets instead of 0-based ones. Resolves#65437.
* Consistently omit column information for msvc targets, matching clang behaviour (previously columns have been omitted from `DILocation`, but not from `DILexicalBlock`).
Optimize catch_unwind to match C++ try/catch
This refactors the implementation of catching unwinds to allow LLVM to inline the "try" closure directly into the happy path, avoiding indirection. This means that the catch_unwind implementation is (after this PR) zero-cost unless a panic is thrown.
https://rust.godbolt.org/z/cZcUSB is an example of the current codegen in a simple case. Notably, the codegen is *exactly the same* if `-Cpanic=abort` is passed, which is clearly not great.
This PR, on the other hand, generates the following assembly:
```asm
# -Cpanic=unwind:
push rbx
mov ebx,0x2a
call QWORD PTR [rip+0x1c53c] # <happy>
mov eax,ebx
pop rbx
ret
mov rdi,rax
call QWORD PTR [rip+0x1c537] # cleanup function call
call QWORD PTR [rip+0x1c539] # <unfortunate>
mov ebx,0xd
mov eax,ebx
pop rbx
ret
# -Cpanic=abort:
push rax
call QWORD PTR [rip+0x20a1] # <happy>
mov eax,0x2a
pop rcx
ret
```
Fixes#64224, and resolves#64222.
Add support for LLVM globals corresponding to miri allocations should be named alloc123
Adds support for this request from @eddyb in #69134:
> That is, if -Zfewer-names is false (usually only because of --emit=llvm-ir), we should use the same name for LLVM globals we generate out of miri allocs as #67133 does in MIR output (allocN).
>
>This way, we can easily see the mapping between MIR and LLVM IR (and it shouldn't be any costlier for regular compilation, which would continue to use unnamed globals).
r? @eddyb
cc @oli-obk
Rename rustc guide
This is in preparation for https://github.com/rust-lang/rustc-guide/issues/470
Needs to be merged after we actually rename the guide.
Have used this to rename:
`git grep -l 'rustc_guide' | xargs sed -i 's/rustc_guide/rustc_dev_guide/g'`
`git grep -l 'rustc-guide' | xargs sed -i 's/rustc-guide/rustc-dev-guide/g'`
`git grep -l 'rustc guide' | xargs sed -i 's/rustc guide/rustc dev guide/g'`
Change DIBuilderCreateEnumerator signature to match LLVM 9
* Change DIBuilderCreateEnumerator signature to match LLVM 9 C API.
* Use provided is unsigned flag when emitting enumerators.
