Chrome links .rlibs with /WHOLEARCHIVE or -Wl,--whole-archive to prevent
the linker from discarding static initializers. This works well, except
on Windows x86, where lld complains:
error: /safeseh: lib.rmeta is not compatible with SEH
The fix is simply to mark the .rmeta as SAFESEH aware. This is trivially
true, since the metadata file does not contain any executable code.
Removes the backwards-compatible `LinkSelfContainedDefault`, by
incorporating the remaining specifics into `LinkSelfContained`.
Then renames the modern options to keep the old name.
After #113716, we can make `#![no_builtins]` crates participate in LTO again.
`#![no_builtins]` with LTO does not result in undefined references to the error.
Currently, combining +bundle and +whole-archive works only with
#![feature(packed_bundled_libs)]
This crate feature is independent of the -Zpacked-bundled-libs
command line option.
This commit stabilizes the #![feature(packed_bundled_libs)] crate
feature and implicitly enables it only when the +bundle and
+whole-archive link modifiers are combined. This allows rlib
crates to use the +whole-archive link modifier with native
libraries and have all symbols included in the linked library
to be included in downstream staticlib crates that use the rlib as
a dependency. Other cases requiring the packed_bundled_libs
behavior still require the -Zpacked-bundled-libs command line
option, which can be stabilized independently in the future.
Per discussion on https://github.com/rust-lang/rust/issues/108081
there is no risk of regression stabilizing the crate feature in
this way because the combination of +bundle,+whole-archive link
modifiers was previously not allowed.
Infer `Lld::No` linker hint when the linker stem is a generic compiler driver
This PR basically reverts the temporary solution in https://github.com/rust-lang/rust/pull/113631 to a more long-term solution.
r? ``@petrochenkov``
In [this comment](https://github.com/rust-lang/rust/pull/113631#issuecomment-1634598238), you had ideas about a long-term solution:
> I wonder what a good non-temporary solution for the inference would look like.
>
> * If the default is `(Cc::No, Lld::Yes)` (e.g. `rust-lld`)
>
> * and we switch to some specific platform compiler (e.g. `-C linker=arm-none-eabi-gcc`), should we change to `Lld::No`? Maybe yes?
> * and we switch to some non-default but generic compiler `-C linker=clang`? Then maybe not?
>
> * If the default is `(Cc::Yes, Lld::Yes)` (e.g. future x86_64 linux with default LLD)
>
> * and we switch to some specific platform compiler (e.g. `-C linker=arm-none-eabi-gcc`), should we change to `Lld::No`? Maybe yes?
> * and we switch to some non-default but generic compiler `-C linker=clang`? Then maybe not?
>
I believe that we should infer the `Lld::No` linker hint for any `-Clinker` override, and all the cases above:
- the linker drivers have their own defaults, so in my mind `-Clinker` is a signal to use its default linker / flavor, rather than ours or the target's. In the case of generic compilers, it's more likely than not going to be `Lld::No`. I would expect this to be the case in general, even when including platform-specific compilers.
- the guess will be wrong if the linker driver uses lld by default (and we also don't want to search for `-fuse-ld` link args), but will work in the more common cases. And the minority of other cases can fix the wrong guess by opting into the precise linker flavor.
- this also ensures backwards-compatibility: today, even on targets with an lld default and overriding the linker, rustc will not use lld. That includes `thumbv6m-none-eabi` where issue #113597 happened.
It looks like the simplest option, and the one with least churn: we maintain the current behavior in ambiguous cases.
I've tested that this works on #113597, as expected from the failure.
(I also have a no-std `run-make` test using a custom target json spec: basically simulating a future `x86_64-unknown-linux-gnu` using an lld flavor by default, to check that e.g. `-Clinker=clang` doesn't use lld. I could add that test to this PR, but IIUC such a custom target requires `cargo -Z build-std` and we have no tests depending on this cargo feature yet. Let me know if you want to add this test of the linker inference for such targets.)
What do you think ?
De-duplicate consecutive libs when printing native-static-libs
This PR adds a de-duplicate step just before printing the `native-static-libs`.
This step de-duplicates all the consecutive libs based only on the relevant comparison elements (this exclude spans, ast elements, ...).
Fixes https://github.com/rust-lang/rust/issues/113209
Like for rlibs, the paths on the linker command line need to be relative
paths if the sysroot was specified by the user to be a relative path.
Dylibs put the path in /LIBPATH instead of into the file path of the
library itself, so we rehome the libpath and adjust the rehoming function
to be able to support both use cases, rlibs and dylibs.
When the `--sysroot` is specified as relative to the current working
directory, the sysroot's rlibs should also be specified as relative
paths. Otherwise, the current working directory ends up in the
absolute paths, and in the linker command line. And the entire linker
command line appears in the PDB file generated by the MSVC linker.
When adding an rlib to the linker command line, if the rlib's canonical
path is in the sysroot's canonical path, then use the current sysroot
path + filename instead of the full absolute path to the rlib. This
means that when `--sysroot=foo` is specified, the linker command line
will contain `foo/rustlib/target/lib/lib*.rlib` instead of the full
absolute path to the same.
This addresses https://github.com/rust-lang/rust/issues/112586
Write to stdout if `-` is given as output file
With this PR, if `-o -` or `--emit KIND=-` is provided, output will be written to stdout instead. Binary output (those of type `obj`, `llvm-bc`, `link` and `metadata`) being written this way will result in an error unless stdout is not a tty. Multiple output types going to stdout will trigger an error too, as they will all be mixded together.
This implements https://github.com/rust-lang/compiler-team/issues/431
The idea behind the changes is to introduce an `OutFileName` enum that represents the output - be it a real path or stdout - and to use this enum along the code paths that handle different output types.
Force all native libraries to be statically linked when linking a static binary
Previously, `#[link]` without an explicit `kind = "static"` would confuse the linker and end up producing a dynamically linked library because of the `-Bdynamic` flag. However this binary would not work correctly anyways since it was linked with startup code for a static binary.
This PR solves this by forcing all native libraries to be statically linked when the output is a static binary that cannot link to dynamic libraries anyways.
Fixes#108878Fixes#102993
If `-o -` or `--emit KIND=-` is provided, output will be written
to stdout instead. Binary output (`obj`, `llvm-bc`, `link` and
`metadata`) being written this way will result in an error unless
stdout is not a tty. Multiple output types going to stdout will
trigger an error too, as they will all be mixded together.
Go through an intermediate pair of `cc`and `lld` hints instead of mapping CLI options to `LinkerFlavor` directly, and use the target's default linker flavor as a reference.
Each of `{D,Subd}iagnosticMessage::{Str,Eager}` has a comment:
```
// FIXME(davidtwco): can a `Cow<'static, str>` be used here?
```
This commit answers that question in the affirmative. It's not the most
compelling change ever, but it might be worth merging.
This requires changing the `impl<'a> From<&'a str>` impls to `impl
From<&'static str>`, which involves a bunch of knock-on changes that
require/result in call sites being a little more precise about exactly
what kind of string they use to create errors, and not just `&str`. This
will result in fewer unnecessary allocations, though this will not have
any notable perf effects given that these are error paths.
Note that I was lazy within Clippy, using `to_string` in a few places to
preserve the existing string imprecision. I could have used `impl
Into<{D,Subd}iagnosticMessage>` in various places as is done in the
compiler, but that would have required changes to *many* call sites
(mostly changing `&format("...")` to `format!("...")`) which didn't seem
worthwhile.
Adds support for LLVM [SafeStack] which provides backward edge control
flow protection by separating the stack into two parts: data which is
only accessed in provable safe ways is allocated on the normal stack
(the "safe stack") and all other data is placed in a separate allocation
(the "unsafe stack").
SafeStack support is enabled by passing `-Zsanitizer=safestack`.
[SafeStack]: https://clang.llvm.org/docs/SafeStack.html
Fix local libs not included when printing native static libs
This PR fixes https://github.com/rust-lang/rust/issues/111643 by adding the local used libs to the printed `--print=native-static-libs` output.
It seems that `--print=native-static-libs` doesn't have any test, so I added one. It's very simple and doesn't even tries to compile the result to a binary as I don't know how to handle external library linking in CI. (Note that https://github.com/rust-lang/rust/blob/master/tests/run-make/staticlib-dylib-linkage/Makefile does compile to a binary)
r? `@bjorn3`
Support linking to rust dylib with --crate-type staticlib
This allows for example dynamically linking libstd, while statically linking the user crate into an executable or C dynamic library. For this two unstable flags (`-Z staticlib-allow-rdylib-deps` and `-Z staticlib-prefer-dynamic`) are introduced. Without the former you get an error. The latter is the equivalent to `-C prefer-dynamic` for the staticlib crate type to indicate that dynamically linking is preferred when both options are available, like for libstd. Care must be taken to ensure that no crate ends up being merged into two distinct staticlibs that are linked together. Doing so will cause a linker error at best and undefined behavior at worst. In addition two distinct staticlibs compiled by different rustc may not be combined under any circumstances due to some rustc private symbols not being mangled.
To successfully link a staticlib, `--print native-static-libs` can be used while compiling to ask rustc for the linker flags necessary when linking the staticlib. This is an existing flag which previously only listed native libraries. It has been extended to list rust dylibs too. Trying to locate libstd yourself to link against it is not supported and may break if for example the libstd of multiple rustc versions are put in the same directory.
For an example on how to use this see the `src/test/run-make-fulldeps/staticlib-dylib-linkage/` test.
Currently a `{D,Subd}iagnosticMessage` can be created from any type that
impls `Into<String>`. That includes `&str`, `String`, and `Cow<'static,
str>`, which are reasonable. It also includes `&String`, which is pretty
weird, and results in many places making unnecessary allocations for
patterns like this:
```
self.fatal(&format!(...))
```
This creates a string with `format!`, takes a reference, passes the
reference to `fatal`, which does an `into()`, which clones the
reference, doing a second allocation. Two allocations for a single
string, bleh.
This commit changes the `From` impls so that you can only create a
`{D,Subd}iagnosticMessage` from `&str`, `String`, or `Cow<'static,
str>`. This requires changing all the places that currently create one
from a `&String`. Most of these are of the `&format!(...)` form
described above; each one removes an unnecessary static `&`, plus an
allocation when executed. There are also a few places where the existing
use of `&String` was more reasonable; these now just use `clone()` at
the call site.
As well as making the code nicer and more efficient, this is a step
towards possibly using `Cow<'static, str>` in
`{D,Subd}iagnosticMessage::{Str,Eager}`. That would require changing
the `From<&'a str>` impls to `From<&'static str>`, which is doable, but
I'm not yet sure if it's worthwhile.
Fix Unreadable non-UTF-8 output on localized MSVC
Fixes#35785 by converting non UTF-8 linker output to Unicode using the OEM code page.
Before:
```text
= note: Non-UTF-8 output: LINK : fatal error LNK1181: cannot open input file \'m\x84rchenhaft.obj\'\r\n
```
After:
```text
= note: LINK : fatal error LNK1181: cannot open input file 'märchenhaft.obj'
```
The difference is more dramatic if using a non-ascii language pack for Windows.
Fixes https://github.com/rust-lang/rust/issues/110912
Checking `flavor == RlibFlavor::Normal` was accidentally lost in
601fc8b36bhttps://github.com/rust-lang/rust/pull/105601
That caused combining +whole-archive and +bundle link modifiers on
non-rlib crates to fail with a confusing error message saying that
combination is unstable for rlibs. In particular, this caused the
build to fail when +whole-archive was used on staticlib crates, even
though +whole-archive effectively does nothing on non-bin crates because
the final linker invocation is left to an external build system.
Fixes#35785 by converting non UTF-8 linker output to Unicode using the OEM code page.
Before:
```text
= note: Non-UTF-8 output: LINK : fatal error LNK1181: cannot open input file \'m\x84rchenhaft.obj\'\r\n
```
After:
```text
= note: LINK : fatal error LNK1181: cannot open input file 'märchenhaft.obj'
```
The difference is more dramatic if using a non-ascii language pack for Visual Studio.
The name of NativeLib will be presented
Fixes#109144
I was working on a quick fix, but found change the name from `Option<Symbol>` to `Symbol` make life a little bit easier.
