Since RFC 3052 soft deprecated the authors field anyway, hiding it from
crates.io, docs.rs, and making Cargo not add it by default, and it is
not generally up to date/useful information, we should remove it from
crates in this repo.
[debuginfo] Emit associated type bindings in trait object type names.
This PR updates debuginfo type name generation for trait objects to include associated type bindings and auto trait bounds -- so that, for example, the debuginfo type name of `&dyn Iterator<Item=Foo>` and `&dyn Iterator<Item=Bar>` don't both map to just `&dyn Iterator` anymore.
The following table shows examples of debuginfo type names before and after the PR:
| type | before | after |
|------|---------|-------|
| `&dyn Iterator<Item=u32>>` | `&dyn Iterator` | `&dyn Iterator<Item=u32>` |
| `&(dyn Iterator<Item=u32>> + Sync)` | `&dyn Iterator` | `&(dyn Iterator<Item=u32> + Sync)` |
| `&(dyn SomeTrait<bool, i8, Bar=u32>> + Send)` | `&dyn SomeTrait<bool, i8>` | `&(dyn SomeTrait<bool, i8, Bar=u32>> + Send)` |
For targets that need C++-like type names, we use `assoc$<Item,u32>` instead of `Item=u32`:
| type | before | after |
|------|---------|-------|
| `&dyn Iterator<Item=u32>>` | `ref$<dyn$<Iterator> >` | `ref$<dyn$<Iterator<assoc$<Item,u32> > > >` |
| `&(dyn Iterator<Item=u32>> + Sync)` | `ref$<dyn$<Iterator> >` | `ref$<dyn$<Iterator<assoc$<Item,u32> >,Sync> >` |
| `&(dyn SomeTrait<bool, i8, Bar=u32>> + Send)` | `ref$<dyn$<SomeTrait<bool, i8> > >` | `ref$<dyn$<SomeTrait<bool,i8,assoc$<Bar,u32> > >,Send> >` |
The PR also adds self-profiling measurements for debuginfo type name generation (re. https://github.com/rust-lang/rust/issues/86431). It looks like the compiler spends up to 0.5% of its time in that task, so the potential for optimizing it via caching seems limited.
However, the perf run also shows [the biggest regression](https://perf.rust-lang.org/detailed-query.html?commit=585e91c718b0b2c5319e1fffd0ff1e62aaf7ccc2&base_commit=b9197978a90be6f7570741eabe2da175fec75375&benchmark=tokio-webpush-simple-debug&run_name=incr-unchanged) in a test case that does not even invoke the code in question. This suggests that the length of the names we generate here can affect performance by influencing how much data the linker has to copy around.
Fixes https://github.com/rust-lang/rust/issues/86134.
Don't use gc-sections with profile-generate.
When building with profile-generate don't call gc_sections as this can
can sometimes strip out profile data. This missing information in the
prof files can then result in missing functions when using the profile
information.
#78226
r? `@Mark-Simulacrum`
Remove nondeterminism in multiple-definitions test
Compare all fields in `DllImport` when sorting to avoid nondeterminism in the error for multiple inconsistent definitions of an extern function. Restore the multiple-definitions test.
Resolves#87084.
CTFE/Miri engine Pointer type overhaul
This fixes the long-standing problem that we are using `Scalar` as a type to represent pointers that might be integer values (since they point to a ZST). The main problem is that with int-to-ptr casts, there are multiple ways to represent the same pointer as a `Scalar` and it is unclear if "normalization" (i.e., the cast) already happened or not. This leads to ugly methods like `force_mplace_ptr` and `force_op_ptr`.
Another problem this solves is that in Miri, it would make a lot more sense to have the `Pointer::offset` field represent the full absolute address (instead of being relative to the `AllocId`). This means we can do ptr-to-int casts without access to any machine state, and it means that the overflow checks on pointer arithmetic are (finally!) accurate.
To solve this, the `Pointer` type is made entirely parametric over the provenance, so that we can use `Pointer<AllocId>` inside `Scalar` but use `Pointer<Option<AllocId>>` when accessing memory (where `None` represents the case that we could not figure out an `AllocId`; in that case the `offset` is an absolute address). Moreover, the `Provenance` trait determines if a pointer with a given provenance can be cast to an integer by simply dropping the provenance.
I hope this can be read commit-by-commit, but the first commit does the bulk of the work. It introduces some FIXMEs that are resolved later.
Fixes https://github.com/rust-lang/miri/issues/841
Miri PR: https://github.com/rust-lang/miri/pull/1851
r? `@oli-obk`
Handle non-integer const generic parameters in debuginfo type names.
This PR fixes an ICE introduced by https://github.com/rust-lang/rust/pull/85269 which started emitting const generic arguments for debuginfo names but did not cover the case where such an argument could not be evaluated to a flat string of bits.
The fix implemented in this PR is very basic: If `try_eval_bits()` fails for the constant in question, we fall back to generating a stable hash of the constant and emit that instead. This way we get a (virtually) unique name and side step the problem of generating a string representation of a potentially complex value.
The downside is that the generated name will be rather opaque. E.g. the regression test adds a function `const_generic_fn_non_int<()>` which is then rendered as `const_generic_fn_non_int<{CONST#fe3cfa0214ac55c7}>`. I think it's an open question how to deal with this more gracefully.
I'd be interested in ideas on how to do this better.
r? `@wesleywiser`
cc `@dpaoliello` (do you see any problems with this approach?)
cc `@Mark-Simulacrum` & `@nagisa` (who I've seen comment on debuginfo issues recently -- anyone else?)
Fixes https://github.com/rust-lang/rust/issues/86893
When building with profile-generate request that metadata is kept
during the gc_sections call, as this can sometimes strip out profile
data.
This missing information in the prof files can then result in missing
functions when using the profile information.
Improve opaque pointers support
Opaque pointers are coming, and rustc is not ready.
This adds partial support by passing an explicit load type to LLVM. Two issues I've encountered:
* The necessary type was not available at the point where non-temporal copies were generated. I've pushed the code for that upwards out of the memcpy implementation and moved the position of a cast to make do with the types we have available. (I'm not sure that cast is needed at all, but have retained it in the interest of conservativeness.)
* The `PlaceRef::project_deref()` function used during debuginfo generation seems to be buggy in some way -- though I haven't figured out specifically what it does wrong. Replacing it with `load_operand().deref()` did the trick, but I don't really know what I'm doing here.
Simply shift the bitcast from the store to the load, so that
we can use the destination type. I'm not sure the bitcast is
really necessary, but keeping it for now.
I'm not really sure what is wrong here, but I was getting load
type mismatches in the debuginfo code (which is the only place
using this function).
Replacing the project_deref() implementation with a generic
load_operand + deref did the trick.
This makes load generation compatible with opaque pointers.
The generation of nontemporal copies still accesses the pointer
element type, as fixing this requires more movement.
Refactor linker code
This merges `LinkerInfo` into `CrateInfo` as there is no reason to keep them separate. `LinkerInfo::to_linker` is merged into `get_linker` as both have different logic for each linker type and `to_linker` is directly called after `get_linker`. Also contains a couple of small cleanups.
See the individual commits for all changes.
Previously, only the fields would be displayed with no indication of the
variant name. If you already knew the enum was univariant, this was ok
but if the enum was univariant because of layout, for example, a
`Result<T, !>` then it could be very confusing which variant was the
active one.
Improve debug symbol names to avoid ambiguity and work better with MSVC's debugger
There are several cases where names of types and functions in the debug info are either ambiguous, or not helpful, such as including ambiguous placeholders (e.g., `{{impl}}`, `{{closure}}` or `dyn _'`) or dropping qualifications (e.g., for dynamic types).
Instead, each debug symbol name should be unique and useful:
* Include disambiguators for anonymous `DefPathDataName` (closures and generators), and unify their formatting when used as a path-qualifier vs item being qualified.
* Qualify the principal trait for dynamic types.
* If there is no principal trait for a dynamic type, emit all other traits instead.
* Respect the `qualified` argument when emitting ref and pointer types.
* For implementations, emit the disambiguator.
* Print const generics when emitting generic parameters or arguments.
Additionally, when targeting MSVC, its debugger treats many command arguments as C++ expressions, even when the argument is defined to be a symbol name. As such names in the debug info need to be more C++-like to be parsed correctly:
* Avoid characters with special meaning (`#`, `[`, `"`, `+`).
* Never start a name with `<` or `{` as this is treated as an operator.
* `>>` is always treated as a right-shift, even when parsing generic arguments (so add a space to avoid this).
* Emit function declarations using C/C++ style syntax (e.g., leading return type).
* Emit arrays as a synthetic `array$<type, size>` type.
* Include a `$` in all synthetic types as this is a legal character for C++, but not Rust (thus we avoid collisions with user types).
Also an fix issue with tuple type names where we can't cast to them in
natvis (required by the visualizer for `HashMap`) because of
peculiarities with the natvis expression evaluator.
Add support for leaf function frame pointer elimination
This PR adds ability for the target specifications to specify frame
pointer emission type that's not just “always” or “whatever cg decides”.
In particular there's a new mode that allows omission of the frame
pointer for leaf functions (those that don't call any other functions).
We then set this new mode for Aarch64-based Apple targets.
Fixes#86196
Add suggestions for "undefined reference" link errors
This adds a suggestion for "undefined reference to ..." linking errors to install or specify the location to an external library. Since there is no defined error format for linkers, we just check if there was a failure and if that failure contains the string `undefined reference to`. This also makes it impossible to test this, since the output depends on the system linker. The output now looks like:
```
error: linking with `cc` failed: exit status: 1
|
= note: "cc" "-m64" "linking_failure.linking_failure.7rcbfp3g-cgu.0.rcgu.o" "linking_failure.linking_failure.7rcbfp3g-cgu.1.rcgu.o" "linking_failure.linking_failure.7rcbfp3g-cgu.2.rcgu.o" "linking_failure.linking_failure.7rcbfp3g-cgu.3.rcgu.o" "linking_failure.linking_failure.7rcbfp3g-cgu.4.rcgu.o" "linking_failure.linking_failure.7rcbfp3g-cgu.5.rcgu.o" "linking_failure.linking_failure.7rcbfp3g-cgu.6.rcgu.o" "linking_failure.linking_failure.7rcbfp3g-cgu.7.rcgu.o" "linking_failure.linking_failure.7rcbfp3g-cgu.8.rcgu.o" "linking_failure.53u64zklswtfazes.rcgu.o" "-Wl,--as-needed" "-L" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-Wl,--start-group" "-Wl,-Bstatic" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-01ce3ba5c629d02f.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/libpanic_unwind-f1f2102409186354.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/libminiz_oxide-1e8b6b56a999f838.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/libadler-d0e93eb4e14f1d19.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/libobject-1d7e39d75d082b43.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/libaddr2line-ade42e945045b261.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/libgimli-1a65064fccf4ebc1.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd_detect-4d699c310fdfe72d.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_demangle-1cafa68a696ec800.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/libhashbrown-e9f1c8c4dab2f046.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_alloc-ecc1a743be25c7f7.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/libunwind-e074031c4b66b6b6.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcfg_if-9aa6ed9f1d3bfd53.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblibc-7862bf96c2250ca0.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/liballoc-f02ce0dc7895b5fd.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_core-3af9c60917570521.rlib" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore-ca16fc7bb3645684.rlib" "-Wl,--end-group" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcompiler_builtins-d8e1a5b7299604cc.rlib" "-Wl,-Bdynamic" "-lgcc_s" "-lutil" "-lrt" "-lpthread" "-lm" "-ldl" "-lc" "-Wl,--eh-frame-hdr" "-Wl,-znoexecstack" "-L" "/home/smit/rustc-dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-o" "linking_failure" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro" "-Wl,-znow" "-nodefaultlibs"
= note: /usr/bin/ld: linking_failure.linking_failure.7rcbfp3g-cgu.3.rcgu.o: in function `linking_failure::main':
linking_failure.7rcbfp3g-cgu.3:(.text._ZN15linking_failure4main17h52b6e3052e444479E+0x3): undefined reference to `doesnt_exist_thiwthwfyl'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
= help: some `extern` functions couldn't be found; you may need to install or specify the path to some dependencies
= note: use the -L flag to specify the library lookup path
= note: use the cargo:rustc-link-search directive to specify the library lookup path with Cargo (see https://doc.rust-lang.org/cargo/reference/build-scripts.html#rustc-link-search)
error: aborting due to previous error
```
There are several cases where names of types and functions in the debug info are either ambiguous, or not helpful, such as including ambiguous placeholders (e.g., `{{impl}}`, `{{closure}}` or `dyn _'`) or dropping qualifications (e.g., for dynamic types).
Instead, each debug symbol name should be unique and useful:
* Include disambiguators for anonymous `DefPathDataName` (closures and generators), and unify their formatting when used as a path-qualifier vs item being qualified.
* Qualify the principal trait for dynamic types.
* If there is no principal trait for a dynamic type, emit all other traits instead.
* Respect the `qualified` argument when emitting ref and pointer types.
* For implementations, emit the disambiguator.
* Print const generics when emitting generic parameters or arguments.
Additionally, when targeting MSVC, its debugger treats many command arguments as C++ expressions, even when the argument is defined to be a symbol name. As such names in the debug info need to be more C++-like to be parsed correctly:
* Avoid characters with special meaning (`#`, `[`, `"`, `+`).
* Never start a name with `<` or `{` as this is treated as an operator.
* `>>` is always treated as a right-shift, even when parsing generic arguments (so add a space to avoid this).
* Emit function declarations using C/C++ style syntax (e.g., leading return type).
* Emit arrays as a synthetic `array$<type, size>` type.
* Include a `$` in all synthetic types as this is a legal character for C++, but not Rust (thus we avoid collisions with user types).
This PR adds ability for the target specifications to specify frame
pointer emission type that's not just “always” or “whatever cg decides”.
In particular there's a new mode that allows omission of the frame
pointer for leaf functions (those that don't call any other functions).
We then set this new mode for Aarch64-based Apple targets.
Fixes#86196
Change vtable memory representation to use tcx allocated allocations.
This fixes https://github.com/rust-lang/rust/issues/86324. However i suspect there's more to change before it can land.
r? `@bjorn3`
cc `@rust-lang/miri`
Do not emit alloca for ZST locals with multiple assignments
This extends 35566bfd7d to additionally stop emitting unnecessary allocas for zero sized locals that are assigned multiple times.
When rebuilding the standard library with `-Zbuild-std` this reduces the number of locals that require an allocation from 62315 to 61767.
std: Stabilize wasm simd intrinsics
This commit performs two changes to stabilize Rust support for
WebAssembly simd intrinsics:
* The stdarch submodule is updated to pull in rust-lang/stdarch#1179.
* The `wasm_target_feature` feature gate requirement for the `simd128`
feature has been removed, stabilizing the name `simd128`.
This should conclude the FCP started on #74372 and...
Closes#74372
This commit performs two changes to stabilize Rust support for
WebAssembly simd intrinsics:
* The stdarch submodule is updated to pull in rust-lang/stdarch#1179.
* The `wasm_target_feature` feature gate requirement for the `simd128`
feature has been removed, stabilizing the name `simd128`.
This should conclude the FCP started on #74372 and...
Closes#74372
MVP for using rust-lld as part of cc
Will fix#71519. I need to figure out how to write a test showing that lld is used instead of whatever linker cc normally uses. When I manually run rustc using `echo 'fn main() {}' | RUSTC_LOG=rustc_codegen_ssa:🔙:link=debug ./rustc -Clinker-flavor=gcc-lld --crate-type bin -Clink-arg=-Wl,-v` (thanks to bjorn3 on Zulip), I can see that lld is used, but I'm not sure how to inspect that output in a test.
Use preorder traversal when checking for SSA locals
Traverse blocks in topological sort of dominance partial order, to ensure that
local analyzer correctly identifies locals that are already in static single
assignment form, while avoiding dependency on implicit numeric order of blocks.
When rebuilding the standard library, this change reduces the number of locals
that require an alloca from 62452 to 62348.
ignore test if rust-lld not found
create ld -> rust-lld symlink at build time instead of run time
for testing in ci
copy instead of symlinking
remove linux check
test for linker, suggestions from bjorn3
fix overly restrictive lld matcher
use -Zgcc-ld flag instead of -Clinker-flavor
refactor code adding lld to gcc path
revert ci changes
suggestions from petrochenkov
rename gcc_ld to gcc-ld in dirs
As reported in the stabilization issue, MacOS' linker doesn't support the `-s` and `-S` flags to strip symbols anymore. However, the os ships a separated tool to perform these operations.
This change allows the compiler to use that tool after a target has been compiled to strip symbols.
For rationale, see: https://github.com/rust-lang/rust/issues/72110#issuecomment-641169818
For option selection, see: https://www.unix.com/man-page/osx/1/strip/
Signed-off-by: David Calavera <david.calavera@gmail.com>
Remove the install prefix from the rpath set when using -Crpath
It was broken anyway for rustup installs and nobody seems to have noticed.
Fixes https://github.com/rust-lang/rust/issues/82392
Unify duplicate linker_and_flavor methods in rustc_codegen_{cranelift,ssa}.
The two methods were exactly the same so this removes the cranelift copy. This will help make sure both they don't get out of sync.
Driver improvements
This PR contains a couple of cleanups for the driver and a few small improvements for the custom codegen backend interface. It also implements `--version` and `-Cpasses=list` support for custom codegen backends.
- Combine all native library arguments together, to simplify potential support for library deduplication and similar things
- Split arguments into order-independent and order-dependent, to define more precisely what (pre,post,late)-link-args mean
Tweak wasm_base target spec to indicate linker is not GNU and update linker inferring logic for wasm-ld.
Reported via [Zulip](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/wasi.20linker.20unknown.20argument.3A.20--as-needed): we try passing `--as-needed` to the linker if it's GNU ld which `wasm-ld` is not. Usually this isn't an issue for wasm as we would use the WasmLd linker driver but because the linker in question (`wasm32-unknown-wasi-wasm-ld`) ended with `-ld` our linker inferring [logic](f64503eb55/compiler/rustc_codegen_ssa/src/back/link.rs (L957-L1040)) used the `GccLinker` implementations. (UPD: The linker inferring logic actually didn't apply in this case because the linker is actually invoked through gcc in the reported issue. But it's still worth updating the logic I think.)
This change then has 2 parts:
1. Update wasm_base target spec to indicate `linker_is_gnu: false` plus a few additions of `target.is_like_wasm` to handle flags `wasm-ld` does in fact support.
2. Improve the linker detection logic to properly determine the correct flavor of wasm linker we're using when we can.
We need to add the new `target.is_like_wasm` branches to handle the case where the "linker" used could be something like clang which would then under the hood call wasm-ld.
Preserve metadata w/ Solaris-like linkers.
#84468 moved the `-zignore` linker flag from the `gc_sections` method to `add_as_needed` which is more accurate but Solaris-style linkers will also end up removing an unreferenced ELF sections [1]. This had the unfortunate side effect of causing the `.rustc` section (which has the metada) to be removed which could cause issues when trying to link against the resulting crates or use proc macros.
Since the `-zignore` is positional, we fix this by moving the metadata objects to before the flag.
[1] Specifically a section is considered unreferenced if:
* The section is allocatable
* No other sections bind to (relocate) to this section
* The section provides no global symbols
https://docs.oracle.com/cd/E19683-01/817-3677/6mj8mbtbs/index.html#chapter4-19
Partial support for raw-dylib linkage
First cut of functionality for issue #58713: add support for `#[link(kind = "raw-dylib")]` on `extern` blocks in lib crates compiled to .rlib files. Does not yet support `#[link_name]` attributes on functions, or the `#[link_ordinal]` attribute, or `#[link(kind = "raw-dylib")]` on `extern` blocks in bin crates; I intend to publish subsequent PRs to fill those gaps. It's also not yet clear whether this works for functions in `extern "stdcall"` blocks; I also intend to investigate that shortly and make any necessary changes as a follow-on PR.
This implementation calls out to an LLVM function to construct the actual `.idata` sections as temporary `.lib` files on disk and then links those into the generated .rlib.
BPF target support
This adds `bpfel-unknown-none` and `bpfeb-unknown-none`, two new no_std targets that generate little and big endian BPF. The approach taken is very similar to the cuda target, where `TargetOptions::obj_is_bitcode` is enabled and code generation is done by the linker.
I added the targets to `dist-various-2`. There are [some tests](https://github.com/alessandrod/bpf-linker/tree/main/tests/assembly) in bpf-linker and I'm planning to add more. Those are currently not ran as part of rust CI.
Remove special handling of `box_free` from `LocalAnalyzer`
The special casing of `box_free` predates the use of dominators in
analyzer. It is no longer necessary now that analyzer verifies that
the first assignment dominates all uses.
This does not yet support #[link_name] attributes on functions, the #[link_ordinal]
attribute, #[link(kind = "raw-dylib")] on extern blocks in bin crates, or
stdcall functions on 32-bit x86.
rustc: Store metadata-in-rlibs in object files
This commit updates how rustc compiler metadata is stored in rlibs.
Previously metadata was stored as a raw file that has the same format as
`--emit metadata`. After this commit, however, the metadata is encoded
into a small object file which has one section which is the contents of
the metadata.
The motivation for this commit is to fix a common case where #83730
arises. The problem is that when rustc crates a `dylib` crate type it
needs to include entire rlib files into the dylib, so it passes
`--whole-archive` (or the equivalent) to the linker. The problem with
this, though, is that the linker will attempt to read all files in the
archive. If the metadata file were left as-is (today) then the linker
would generate an error saying it can't read the file. The previous
solution was to alter the rlib just before linking, creating a new
archive in a temporary directory which has the metadata file removed.
This problem from before this commit is now removed if the metadata file
is stored in an object file that the linker can read. The only caveat we
have to take care of is to ensure that the linker never actually
includes the contents of the object file into the final output. We apply
similar tricks as the `.llvmbc` bytecode sections to do this.
This involved changing the metadata loading code a bit, namely updating
some of the LLVM C APIs used to use non-deprecated ones and fiddling
with the lifetimes a bit to get everything to work out. Otherwise though
this isn't intended to be a functional change really, only that metadata
is stored differently in archives now.
This should end up fixing #83730 because by default dylibs will no
longer have their rlib dependencies "altered" meaning that
split-debuginfo will continue to have valid paths pointing at the
original rlibs. (note that we still "alter" rlibs if LTO is enabled to
remove Rust object files and we also "alter" for the #[link(cfg)]
feature, but that's rarely used).
Closes#83730
This commit updates how rustc compiler metadata is stored in rlibs.
Previously metadata was stored as a raw file that has the same format as
`--emit metadata`. After this commit, however, the metadata is encoded
into a small object file which has one section which is the contents of
the metadata.
The motivation for this commit is to fix a common case where #83730
arises. The problem is that when rustc crates a `dylib` crate type it
needs to include entire rlib files into the dylib, so it passes
`--whole-archive` (or the equivalent) to the linker. The problem with
this, though, is that the linker will attempt to read all files in the
archive. If the metadata file were left as-is (today) then the linker
would generate an error saying it can't read the file. The previous
solution was to alter the rlib just before linking, creating a new
archive in a temporary directory which has the metadata file removed.
This problem from before this commit is now removed if the metadata file
is stored in an object file that the linker can read. The only caveat we
have to take care of is to ensure that the linker never actually
includes the contents of the object file into the final output. We apply
similar tricks as the `.llvmbc` bytecode sections to do this.
This involved changing the metadata loading code a bit, namely updating
some of the LLVM C APIs used to use non-deprecated ones and fiddling
with the lifetimes a bit to get everything to work out. Otherwise though
this isn't intended to be a functional change really, only that metadata
is stored differently in archives now.
This should end up fixing #83730 because by default dylibs will no
longer have their rlib dependencies "altered" meaning that
split-debuginfo will continue to have valid paths pointing at the
original rlibs. (note that we still "alter" rlibs if LTO is enabled to
remove Rust object files and we also "alter" for the #[link(cfg)]
feature, but that's rarely used).
Closes#83730
For extern providers, both provide and provide_extern are called.
wasm_import_module_map is already provided in provide, so it doesn't
need to be provided in provide_extern.
Reland - Report coverage `0` of dead blocks
Fixes: #84018
With `-Z instrument-coverage`, coverage reporting of dead blocks
(for example, blocks dropped because a conditional branch is dropped,
based on const evaluation) is now supported.
Note, this PR relands an earlier, reverted PR that failed when compiling
generators. The prior issues with generators has been resolved and a new
test was added to prevent future regressions.
Check out the resulting changes to test coverage of dead blocks in the
test coverage reports in this PR.
r? `@tmandry`
fyi: `@wesleywiser`
Remove unused feature gates
The first commit removes a usage of a feature gate, but I don't expect it to be controversial as the feature gate was only used to workaround a limitation of rust in the past. (closures never being `Clone`)
The second commit uses `#[allow_internal_unstable]` to avoid leaking the `trusted_step` feature gate usage from inside the index newtype macro. It didn't work for the `min_specialization` feature gate though.
The third commit removes (almost) all feature gates from the compiler that weren't used anyway.
Previously, we would generate a single struct with the layout of the
dataful variant plus an extra field whose name contained the value of
the niche (this would only really work for things like `Option<&_>`
where we can determine that the `None` case maps to `0` but for enums
that have multiple tag only variants, this doesn't work).
Now, we generate a union of two structs, one which is the layout of the
dataful variant and one which just has a way of reading the
discriminant. We also generate an enum which maps the discriminant value
to the tag only variants.
We also encode information about the range of values which correspond to
the dataful variant in the type name and then use natvis to determine
which union field we should display to the user.
As a result of this change, all niche-layout enums render correctly in
WinDbg and Visual Studio!
Fixes: #84018
With `-Z instrument-coverage`, coverage reporting of dead blocks
(for example, blocks dropped because a conditional branch is dropped,
based on const evaluation) is now supported.
Note, this PR relands an earlier, reverted PR that failed when compiling
generators. The prior issues with generators has been resolved and a new
test was added to prevent future regressions.
Check out the resulting changes to test coverage of dead blocks in the
test coverage reports in this PR.
The special casing of `box_free` predates the use of dominators in
analyzer. It is no longer necessary now that analyzer verifies that
the first assignment dominates all uses.
